LITERATURE REVIEW FOR 20

POTENTIALLY VIABLE PLANT SPECIES TO

BE USED AS A BIO-DIESEL FEEDSTOCK

Luke Asgill & Erond Perez

Table of Contents

List of Figures ................................................................................................................................................. i

List of Tables ................................................................................................................................................. ii

1. Introduction .......................................................................................................................................... 1

2. Current Biodiesel Fuel Production & Use ............................................................................................. 2

3. Potentially Viable Plant Species to be used as Biodiesel Feed-Stocks .................................................. 4

3.1 Calophyllum Inophyllum (Beauty Leaf) ............................................................................................... 5

3.2 Aleurites Moluccana (Candle Nut Tree) .............................................................................................. 7

3.3 Syagrus Romanzoffiana (Queen Palm) ................................................................................................ 9

3.4 Murraya Exotica (Mock Orange) ....................................................................................................... 11

3.5 Cordyline Manners-Suttoniae (Cordyline) ........................................................................................ 13

3.6 Grevillea Banksii (Grevillea) .............................................................................................................. 15

3.7 Elaeocarpus Grandis (Blue Quandong) ............................................................................................. 17

3.8 Ochna Serrulata (Ochna) ................................................................................................................... 19

3.9 Brachychiton Bidwilli ......................................................................................................................... 21

3.10 Koelreuteria Formosana (Chinese Rain Tree) .................................................................................. 23

3.11 Santalum Album (Sandalwood) ...................................................................................................... 25

3.12 Argemone Mexicana (Mexican poppy) ........................................................................................... 27

3.13 Petalostigma Pubescens (Quinine bush) ......................................................................................... 29

3.14 Brachychiton Acerifolius (Flame Tree) ............................................................................................ 31

3.15 Jagera Pseudorhus (Jagera) ............................................................................................................ 33

3.16 Ricinus Communis (Castor Oil Seed) ............................................................................................... 35

3.17 Atalaya Hemiglauca (Whitewood) .................................................................................................. 37

3.18 Dianella Caerulea (Blue Berry Lily) .................................................................................................. 39

3.19 Pongamia Pinnata (Karanja) ........................................................................................................... 41

3.20 Cocos Nucifera (Coconut Palm) ....................................................................................................... 43

4. Discussion & Evaluation of the Viability for use as a Biodiesel Feed-Stock ........................................ 45

4.1 Harvesting & Potential Yield Analysis: .......................................................................................... 45

4.2 Cultivation Analysis: ...................................................................................................................... 48

4.3 Plant Analysis Summary: ............................................................................................................... 49

4.4 Comparative Analysis: ................................................................................................................... 50

5. Conclusions & Recommendations ...................................................................................................... 52

6. References (Prepared using Mendeley Desktop) ................................................................................ 53

Appendices .................................................................................................................................................. 57

Appendix i Primary Information Regarding Cultivation and Yields of the Native or Naturalised Plant

Species .................................................................................................................................................... 57

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List of Figures

Figure 1 - Calophyllum Inophyllum growing along a beach front, and in a park and its distribution in

Australia. ....................................................................................................................................................... 5

Figure 2 - The fruit & kernels of Calophyllum Inophyllum. ........................................................................... 6

Figure 3 - The Aleurites Moluccana tree, its dispersion throughout Australia and the kernels that it

produces. ...................................................................................................................................................... 7

Figure 4 - The Syagrus Romanzoffian tree, an inflorescence of the fruit produced, and its current and

potential distribution. ................................................................................................................................... 9

Figure 5 - Seeds of a Syagrus Romanzoffiana tree. .................................................................................... 10

Figure 6 - The Murraya Exotica's current and potential distribution in Australia, a full grown shrub, and

the fruit produced. ...................................................................................................................................... 11

Figure 7 - Seed produced from the fruit of a Murraya Exotica tree. .......................................................... 12

Figure 8 - The distribution of Cordyline Manners-Suttoniae, the panicles of fruit produced and a fully

grown tree................................................................................................................................................... 13

Figure 9 - The seeds removed from a fruit of the Cordyline Manners-Suttoniae tree. .............................. 14

Figure 10 - The fruit and distribution of Grevillea Banksii in Australia. ...................................................... 15

Figure 11 - Seeds taken from a Grevillea Banksii plant............................................................................... 16

Figure 12 - The racemes of flowers bloomed from Elaocarpus Grandis. On the right, a full grown tree and

the current and potential distributions on the bottom left. ...................................................................... 17

Figure 13 - Fruit and kernel of Elaeocarpus Grandis. .................................................................................. 18

Figure 14 - The Ochna Serrulata shrub, with its yellow flowers and the fruits produced. In the bottom

right, is the distribution of the shrub in Australia. ...................................................................................... 19

Figure 15 - Seeds produced by an Ochna Serrulata shrub. ......................................................................... 20

Figure 16 - Brachychiton Bidwilli, its current distribution and its potential distribution in Australia. ....... 21

Figure 17 - The dried fruit and seeds within of a Brachychiton Bidwilli shrub/tree. .................................. 22

Figure 18 - The current and potential distribution of Koelreuteria Formosana, the fruit it bears and a full

grown tree................................................................................................................................................... 23

Figure 19 - Seeds extracted from the fruit of a Koelreuteria Formosana tree. .......................................... 24

Figure 20 - The Santalum Album (or Sandalwood) tree, its current distribution in Australia and the small

clusters of fruit produced. .......................................................................................................................... 25

Figure 21 - The dried fruit and seeds contained from Santalum Album. ................................................... 26

Figure 22 - The current and potential distribution of the Mexican poppy and a fully grown shrub. ......... 27

Figure 23 - The fruit produced by an Argemone Mexicana plant and the seeds contained. ..................... 28

Figure 24 - A full grown shrub with matured fruits and the current distribution of Petalostigma

Pubescens. ................................................................................................................................................... 29

Figure 25 - Peeled back dry skin of a fruit from a Petalostigma Pubescens plant, reveealing the endocarp.

.................................................................................................................................................................... 30

Figure 26 - The current distribution of Brachychiton Acerifolius in Autralia, a fully blooming tree and the

large fruits produced................................................................................................................................... 31

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Figure 27 - Seeds extracted from a fruit of the Brachychiton Acerifolius. .................................................. 32

Figure 28 - Jagera Pseudorhus, its fruits and the current distribution within Australia. ............................ 33

Figure 29 - Seeds produced by Jagera Pseudorhus..................................................................................... 34

Figure 30 - Ricinus Communis, the seeds produced and its current and potential distribution through

Australia. ..................................................................................................................................................... 35

Figure 31 - Seeds produced by Ricinus Communis. ..................................................................................... 36

Figure 32 - The current distribution of Atalaya Hemiglauca, a full grown tree and the fruits yielded. ..... 37

Figure 33 Fruits produced by Atalaya Hemiglauca. ................................................................................. 38

Figure 34 - Dianella Caerulea, its flowers and a distribution map for New South Wales........................... 39

Figure 35 - Seeds produced by Dianella Caerulea. ..................................................................................... 40

Figure 36 - Pongamia Pinnata, a cluster of the pod fruits and a map of the trees current distribution. ... 41

Figure 37 - Seeds produced by Pongamia Pinnata. .................................................................................... 42

Figure 38 - Full grow Cocos Nucifera trees, the bunches of fruit produced and the current distribution in

Australia. ..................................................................................................................................................... 43

Figure 39 - A cracked open coconut revealing the white copra within. ..................................................... 44

Figure 40 - Graphical Representation of the Oil and Seed or Kernel Yields. .............................................. 46

Figure 41 - A comparison of the oil content by mass. ................................................................................ 47

List of Tables

Table 1 - Basic information covering the cultivation and yields of two currently emplyed biodisel feed-

stocks [4750]. ............................................................................................................................................ 51

Table 2 - Summarised, tabular representation of the key information presented in Section 3. ................ 58

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1. Introduction

Transportation has always been a critical aspect of society granting longer, faster and more effective

travel, in turn allowing trade to flourish. The diesel engine, one of the primary devices utilised for travel

in modern society, was firstly integrated into society after petroleum mining and oil refining techniques

developed. Petroleum based diesel (or petrodiesel) has long since been the fuel of choice for not just the

diesel engine, but in many cases, for transportation as a whole. Petroleum mining and the production of

diesel fuel from petroleum were and still are a more cost-beneficial alternative to the biodiesels originally

used. It is due to its wide spread use and cost superiority that petroleum based diesel, as well as other

products derived from petroleum, have become established as a major constituent of the global economy.

However, since industrialising, concerns around petrodiesel and its use continue to grow.

In 1993, legislative action was put in place to reduce on road diesel fuel sulphur levels to 500 ppm. The

primary reason for this stems from the amount of particulate matter produced from exhaust pipes due to

the oxidisation of sulphur particles within the combustion chamber. This particulate matter had an evident

effect on human health. Aside from such direct health effects, there is the constant concern over peak oil.

Though peak oil speculations are difficult to make, it is inadvertently clear that demand for petroleum

based products continues to grow while the known supply continues to diminish. Furthermore, with an

increasing demand and a fluctuating supply, costs for petrodiesel continue to increase which can impose

significant strains on the global economy, particularly in the mining and transportation sectors. Even more

prominent recently, has been the climate change issues. Concerns for the global climate, or more heavily

on local climates, due to rising average temperatures have put pressure on the petroleum based diesel

industry. Diesel powered engines produce more polluting emissions than alternative technologies, such

as gasoline, electric or fuel-cell powered engines.

It is because of the recent climate concerns that alternative energy sources and technologies to currently

employed ones are being sought after. Organically based diesel fuels (or biodiesels), such as those derived

from plant matter, are one such alternative. Biodiesel fuels are produced from renewable sources

negating concerns over peak oil and thus limiting potential pressure on the economy. Also, the most

publicly apparent harmful emission to the environment is carbon dioxide and as biodiesels are generated

and burnt on a closed carbon cycle (just as much or less CO2 is produced when burning biodiesels as the

plants they are derived from consume), the use of such fuels helps appease concerns over local and global

climates. In addition, the use of biodiesel fuels does not need a reform or change of current infrastructure

and technologies, unlike electric, solar or fuel cell powered vehicles. This is particularly so for domestic

environments.

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2. Current Biodiesel Fuel Production & Use

The idea of using biofuels in an internal combustion engine dates back to

1929 when Rudolph Diesel first fired his newly invented diesel engine with raw

vegetable (peanut) oil. However, Diesel and others discovered that fuelling a diesel

engine with vegetable oils could reduce atomization, lower heating value and

worsen combustion and cause other long-term problems including pump wear and

carbon/coke deposits.

In recent years, biofuels producers have achieved significant improvements in

crop production and processing efficiencies and today the volume of biofuels

produced in a specific planted area is several times higher than it used to be.

Improved production methods and technologies are expected to increase

efficiencies even further.

One of the main goals of developing the biofuels sector is sustainability. The

sustainability driver is based on the three pillars of economic, social and

environmental sustainability. In economic terms, biofuels production has to be cost-

effective and competitive. In social terms, biofuels development can create a

massive new demand in the agricultural economy. As biofuels production is an

agricultural process, the same elements and inputs contribute to its overall

efficiency as for existing agricultural production systems. [1]

Biofuel production is ever increasing. According to the latest official statistics, global production of

biofuels reached over 34 million tons (Mtoe) of oil in 2007 which accounts for 1.5% of total road related

fuel consumption. By 2015, biofuel production is projected to reach 60 Mtoe and over 90 Mtoe by 2030.

Currently, Brazil and USA are the leaders in biofuel production in which both countries produce mainly

bioethanol [1].

Production of biofuel is a global trend and many other countries also support and participate in

production. Israel focuses on non-edible feedstock such as Jatropha, Castor, cellulosic biomass and algae

for production and aims to process 4-5% of the global biofuel market by 2012. In China, the government

made E10 blends mandatory in five provinces which accounts for 16% of the nations passenger cars.

Thailand mandated a 10% ethanol mix in gasoline, in 2007. Due to this, the palm oil industry now has

plans to supply an increasing portion of national diesel fuel requirements for both Malaysia and Indonesia.

In Canada, government made plans for 45% of the countrys gasoline consumption to contain 10% ethanol

by 2010. India has made goals to reduce its dependence on coal and petroleum to meet its increasing

energy demand; partly by encouraging Jatropha cultivation, which is one of the crucial components of

Indias energy policy. The Indian government is hoping Jatropha biodiesel will replace 20% of its diesel

consumption by 2011 [2]. Finally, in Australia, the government aimed to increase its ethanol and biodiesel

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consumption to 350 mega litres by 2010 by actively encouraging users of government vehicles to purchase

E10 and allowing E5 blends to be sold unlabelled, subject to the results of vehicle testing. Furthermore,

REDI awarded a funding of 5 million AUD for development of high-yield sugarcane for bioethanol

production [3].

Though biofuel production and use has many advantages, there are also a number of drawbacks. For one,

it could impede upon land use for food and other crops since the feed-stocks could also enter the animal

or human food chain. This has caused much controversy over biofuel production, as it is criticized for the

potential to cause food shortages and price rises. There is also the concern over capital costs as most

biofuel production processes cannot supply more than a few per cent of energy requirements sustainably,

while potential biofuel processes that can supply more energy and result in better environmental gains,

have establishing costs of around 750 million AUD. To add to this, there are issues concerned with fuel

properties such as the corrosiveness of ethanol, increase in fuel consumption, pre-ignition knocking, the

need for engine modification, and its modest net energy gain. Lastly, the stability of biofuels; as biodiesel

is chemically an ester molecule, there is every possibility that in the presence of air or oxygen, it will be

hydrolysed to alcohol and acid which causes reduction in flash point and increase in total acid number

along with a number of other undesirable property changes. Consequently, all these make methyl ester

fuels relatively unstable in storage and cause damage to various engine components [2].

Energy efficiency and energy balance of biofuels must be considered as well. Production of biofuels from

raw materials requires energy for farming, transport, a conversion process to achieve the final product,

production or application of fertilizers, pesticides, herbicides and fungicides, all of which also have

environmental consequences. The energy balance of a biofuel is determined by the amount of energy

consumed during the production of the fuel compared to the amount of energy released when it is used

[2].

Though there are a number of potential drawbacks to using biodiesel fuels, most of these relate to

chemical or tribological properties of the fuels produced from the organic sources. This paper focuses on

cultivation requirements and potential oil yields of the organic sources themselves. The potential of

twenty native or naturalised Australian plant species will be examined for their ability to be grown in great

abundance, without impeding upon important crops and their potential yearly oil yields. The purpose of

this paper is to identify a number of plant species viable for use as biodiesel feed-stocks and thus, to serve

as a basis for further research into the fuel quality of viable biodiesel fuel sources.

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3. Potentially Viable Plant Species to be used as Biodiesel Feed-Stocks

For any plant to be considered as a viable candidate for use as a biodiesel fuel source, several standards

must be met. The ecology of which the perspective plant can thrive is the first and most important aspect.

The ecology of a plant dictates where the plant can actually be cultivated, imposing certain limits on its

viability. If applicable areas available for cultivation are limited or occupy land necessary for other

important crops, such as food crops, the plant cannot be considered as an applicable candidate. Thus, to

be suitable, a plant must have wide dispersal ability, whether that be by having a tolerance to a range of

environments and soil types or matching the ecology of available or desired areas. Secondly, cultivation

requirements are a key aspect. The extent of irrigation or drainage systems, weeding, fertilising, trimming

or pruning, planting, growth rates, propagation, and watering needs, have a major effect on large scale

production. In particular, the ability to harvest and collect the fruits and the difficulty to extract either the

seeds or kernels has a major effect on the viability of the plant.

Aside from environmental and cultivation requirements, the potential yields per hectare must also be

considered. This is affected by the number of harvests possible per year, the amount of seeds or kernels

attained per harvest and finally, the oil content of the seeds or kernels. A final consideration that must be

taken into account is the economic necessities revolving around the production of oil from the plants. The

primary costs incorporate the costs of cultivation, which depend on the factors aforementioned and the

costs of oil extraction from collected seeds or kernels. The following pages discuss the ecology and

cultivation requirements of twenty native or naturalised Australian plants that possess potential to be

viable sources of biodiesel fuel.

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3.1 Calophyllum Inophyllum (Beauty Leaf)

Calophyllum Inophyllum, or more commonly known as Beauty Leaf, is a moderately sized tree ranging

between 8-20 m tall that is most notable for its decorative leaves and fragrant flowers, as can be seen in

Figure 1 below [4][5]. The tree grows in tropical and sub-tropical climates (typical temperature range of

18-33 oC) close to sea level. In Australia, Beauty Leaf trees grow in free draining soils near shorelines;

however, it has been seen to grow in various different clay soils both within Australia and various parts of

southern and more central Asia such as Sri Lanka and India [4][5]. Figure 1 below, illustrates the areas in

which Calophyllum Inophyllum has been identified to grow naturally throughout Australia [6]. The areas

seen in Figure 1 all have annual rainfalls that meet the 1000-5000 mm requirement for Calophyllum

Inophyllum to flourish [7]. In most of these areas, the plant grows along hard clay slopes cascading down

to a beach front [4].

Figure 1 - Calophyllum Inophyllum growing along a beach front, and in a park and its distribution in Australia.

The Beauty Leaf tree bears fruits twice a year, the time of which depends upon when the tree was planted

as it is an evergreen. With two yields per year, a healthy tree produces around 8000 fruits, each of which,

contain a kernel within a hard husk [5][6][7]. Both the fruit and kernels produced by the Beauty Leaf tree

can be seen in Figure 2 on the ensuing page.

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Figure 2 - The fruit & kernels of Calophyllum Inophyllum.

Cultivation of Calophyllum Inophyllum:

Calophyllum Inophyllum can be transplanted from nurseries very successfully; although, for the purpose

cultivation, it is more beneficial to grow the trees from direct seeding. The Beauty Leaf tree is a moderately

quick growing tree that can grow up to 1 m tall within a year. It has also been seen to flourish even with

the presence of weeds and other species, so the plant can be grown in mixed cultures and weeding is not

necessary [4][7].

As mentioned, Calophyllum Inophyllum has the ability to grow in a range of clay soils as well as sand, thus

genotypes can be grafted to meet soil types of various locations. Furthermore, this tree can withstand

soils holding a medium to low fertility, although it can only cope with low levels of salinity [5][7]. The

watering requirement is between 1000-5000 mm per year, which is best dispersed throughout the year

to attain the highest yields and maintain the health of the trees.

The fruits are harvested either directly from the tree once they have fully matured or once they have

fallen off [7]. As a number of animals have been noted to eat the fruit, it is safe practice to harvest the

fruits from trees just before they fully mature. The kernels themselves are contained in a hard shell, as

seen from Figure 2 above. These shells must be dried thoroughly so that they can be broken and the

kernels extracted [6][7].

The kernels extracted from the fruit have a dry weight of about 5 g, which, with around 4000 fruits per

harvest (or 8000 per year, as fruits are produced twice a year), results in around 40 kg of kernels, per tree,

per year [5][6]. The spacing of the trees should be 5x5 m, allowing 400 trees per hectare. With 400 trees

per hectare a total of 16000 kg of kernels can be produced per year [6][7]. These kernels contain about

46% useful oil on a unit mass basis, which means each tree can yield approximately 18.4 kg of oil, thus

resulting in about 7360 kg of oil per year, per hectare [6].

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3.2 Aleurites Moluccana (Candle Nut Tree)

The tree seen in Figure 3 below is the Aleurites Moluccana, which has come to be known as the Candle

Nut tree for the traditional use of its waxy seeds and kernels as natural candles. Aleurites Moluccana

grows naturally in both subtropical and tropical dry or wet forest climates, reaching altitudes of up to 700

m [6][8]. In order to flourish, this tree requires an annual rainfall of 640-4300 mm and prefers light or

medium textured soils such as basalt, red loams, sand, limestone, and stone clay [9]. Also seen in Figure

3 below, is the dispersion of the Candle Nut tree in Australia [6]. The Aleurites Moluccana begins bearing

fruit after about 3-4 years of age. The fruits are typically 5-8 cm in diameter and contain two seeds. The

fruits are usually fully mature and begin dropping off the tree between March and May [8][9].

Figure 3 - The Aleurites Moluccana tree, its dispersion throughout Australia and the kernels that it produces.

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Cultivation of Aleurites Moluccana:

Aleurites Moluccana is a moderately fast growing tree reaching up to 1.5 m growth each year and attaining

a maximum height of 10-15 m [8][9]. It is best planted at the beginning of the rainy season from 3-4 month

old nursery raised seedlings. Being nursery raised, the seeds undergo a sowing treatment which hastens

the germination process [9]. It is crucial that lands are cleared of weeds before transplanting the young

trees for cultivation. The trees should also be spaced in 7x7 m blocks for the purposes of oil cropping; this

results in just over 200 plants per hectare [9].

The Aleurites Moluccana tree requires little to no irrigation, it does however, require extensive weeding

during its first year of growth. For every year after the first, until it is fully grown, weeding should be

continued 2-4 times a year [9]. Upon fully maturing, the tree requires little to no maintenance depending

on the aggressiveness of weeds. In regards to its watering requirements, the tree needs 640-4300 mm of

annual rainfall [8][9].

With good conditions, around 7000 fruits can be yielded by any one tree. This totals to 14000 seeds and

thus kernels per tree, per year [9]. The fruits can be collected from the ground around the trees after they

have fully matured and dropped off [9]. Tarps can be utilised by placing them on the floor around the

trees, stopping them from being hidden amongst surrounding foliage. The kernels are extracted by

cracking the hard shells of the seeds once fully dried.

The kernels have a dry weight of about 6 g, which, on a per hectare basis, yields around 16800 kg of dried

kernels per year [9]. As the kernels produced by the Candle Nut tree contains approximately 47% oil on a

unit mass basis, a total of 7900 kg of oil can be produced per year, per hectare [6]. It should be noted that

the oil extracted from candlenuts possess high levels of linoleic acid which presents issues with its use as

a biodiesel fuel [6].

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3.3 Syagrus Romanzoffiana (Queen Palm)

Syagrus Romanzoffiana, the Queen Palm has been declared as a weed by the Australian Government for

its rapid propagation through south-east Queensland [10]. The tree, seen in Figure 4 below, is a tall slender

palm reaching heights around 20 m. It is tolerant towards a number of rainforest conditions such as,

subtropical, tropical, and wetlands. It generally grows near rivers, lakes and other sources of water,

particularly along coastal regions [10][11]. Syagrus Romanzoffiana grows on a range of soil types from

sand to heavy cracking clays and can survive in a wide range of temperatures (from sub-zero temperatures

to low 40s) [10].

Figure 4 - The Syagrus Romanzoffian tree, an inflorescence of the fruit produced, and its current and potential distribution.

The Queen Palms rapid dispersion is attributed to its rapid growth, the large number of fruits and seeds

produced, and the tendency of a number of bird species to collect and spread the seeds. The Queen Palm

can bear fruits throughout the year depending on the conditions. The fruits grow in an inflorescence off

panicles that can grow up to 2 m long [10][11]. The number of fruits contained on any inflorescence ranges

greatly from tree to tree [11]. Although the current distribution of Syagrus Romanzoffiana is limited to

south-east Queensland and north-east New South Wales, the figure above illustrates the potential

distribution of the tree which covers the entire coast of Queensland and a large section of the Northern

Territory [10].

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Cultivation of Syagrus Romanzoffiana:

This plant is most suited for acidic, well-drained soils, thus drainage systems are a necessary requirement

for large scale cultivation [11]. However, as illustrated in Figure 4 above, this tree has substantial

propagation abilities, partly due to its adaptability to a large range of soil types, tolerance to a range of

temperatures, and moderately low watering requirements of 400-2000 mm per year [10][11].

Syagrus Romanzoffiana grows best in full sunlight and is tolerant to mild salinity, but suffers severe

mineral deficiencies on alkaline soils. This tree can quickly deteriorate without proper maintenance, such

as consistent watering throughout the year and maintaining the soil quality [11]. The tree, as mentioned

previously, has a rapid growth rate and responds well to ample moisture and plenty of sunlight. It should

be spaced by 5x5 m, allowing 400 trees per hectare [6][11].

With proper conditions and maintenance, especially watering, sunlight, and soil conditions, around 2000

kg of fruit can be produced per hectare per year, assuming two harvests a year [6]. The fruits can be

collected by cutting the panicles that they grow off from the tree or by collecting them from the floor

once they have fully matured. The fruits are about 2.5-3 cm long and have a diameter of 1-2 cm and

contain a stringy or hairy kernel, seen below [11].

Figure 5 - Seeds of a Syagrus Romanzoffiana tree.

The kernels contained within are extracted by allowing the fruit to ferment, peeling away the soft flesh,

then letting the kernel and husk dry. Once fully dry, the husks surrounding the kernels are easily removed.

Alternatively, the entire seed can be crushed and oil extracted from the resulting mixture of kernel and

husk. This method, although easier, is not as desirable as the husks tend to soak up some of the oil [6][11].

The kernels obtained from Syagrus Romanzoffiana, contain between 41 and 47% oil on a unit mass basis.

Thus, with approximately 2000 kg of kernels per year, per hectare around 820-940 kg of oil can be

produced [6]. This value can vary quite greatly depending on the conditions in which the tree is grown,

the number of harvests made per year, and the method of harvesting.

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3.4 Murraya Exotica (Mock Orange)

Originating from southern and central Asia, Murraya Exotica is a shrub distinguished by its ornate, white

flowers and citrus smelling leaves [12]. The evergreen shrub grows at elevations up to 1300 m on well

drained soils comprised from sedimentary or igneous rocks, such as limestone. It usually grows to a height

of 2-3 m but can grow into a small tree of, at most, 12 m [12]. This shrubs large dispersal throughout

Australia is due to the propagation of its seeds by birds, and can be seen in Figure 6 below. Also seen in

the figure below is the ripened fruit which has a distinctive red colour. Although Murraya Exotica flowers

irregularly throughout the year, the main flowering period is during late spring and early autumn [12]. The

fruits reach a size of about 0.8-2 cm long and contain one or two hairy seeds which have a dry weight of

about 0.06 g [6].

Murraya Exotica is a resilient shrub that can withstand temperatures down to -4 oC and survive through

extended periods of drought. Its annual rainfall requirement is 750-1900 mm [12].

Figure 6 - The Murraya Exotica's current and potential distribution in Australia, a full grown shrub, and the fruit produced.

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Cultivation of Murraya Exotica:

The shrub is grown from direct seeding (transplanting from nurseries is not recommended, especially for

cultivation for oil cropping) and grows at a moderate pace. The shrub however, does not cope well in

mixed cultures and thus weeding is a necessity during its growth [6][12]. Murraya Exotica grows best in

partial shade on limestone.

As seen on the preceding page, this plant has a very large dispersion, growing with low annual rainfalls of

750-1900 mm and on a range of well drained soils. This plant has further potential to be cultivated all

through eastern and central Queensland and the northern sections of Western Australia and Northern

Territory.

The shrubs should be spaced 2x2 m allowing 2500 plants per hectare. A healthy shrub can produce around

2500 fruits or 5000 seeds in a year. The seeds are small, as seen in Figure 7 below, and have a weight of

0.06 g, yielding 750 kg of seeds per hectare, per year [6]. The dried seeds have an oil content of about

22%, which yields a total of 165 kg of oil per hectare, per year [6].

Figure 7 - Seed produced from the fruit of a Murraya Exotica tree.

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3.5 Cordyline Manners-Suttoniae (Cordyline)

Commonly referred to as simply Cordyline, the Cordyline Manners-Suttoniae is a small tree that somewhat

resembles palm trees. It is an evergreen tree that typically grows in rainforests, but has also been seen in

various other forest climates [13]. The tree grows near swamps or other areas with poorly drained soils.

The tree usually grows to about 2-3 m tall, but sometimes reaches up to 5 m [13].

Figure 8 - The distribution of Cordyline Manners-Suttoniae, the panicles of fruit produced and a fully grown tree.

The figure above illustrates the panicles of fruit which can be produced throughout the year. These

panicles reach lengths of about 25 cm and the fruits have a diameter of around 1-1.5 cm [13]. Also seen

in Figure 8 is the current distribution of the Cordyline tree within Australia [6].

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Cultivation of Cordyline Manners-Suttoniae:

This small tree grows best in well shaded areas with a plentiful supply of water. It is easily identifiable

when this tree does not have sufficient shading as the leaves quickly scorch under direct sunlight. The tree

can however, withstand dry conditions so long as irrigation systems are utilised appropriately [13].

Cordylines continue to flourish in the presence of other species and so can be grown in mixed species as

an understory plant [13]. Each tree takes up a very small amount of space allowing for a total of around

10000 trees per hectare [6]. The fruits can be collected by picking them directly from the tree by cutting

off the panicles that they grow on and the seeds, as seen in Figure 9 below, can be extracted with relative

ease as the fruits are fairly soft.

Figure 9 - The seeds removed from a fruit of the Cordyline Manners-Suttoniae tree.

On a per hectare basis, around 3000 kg of seeds can be produced by Cordylines. The seeds have an oil

content, per unit mass, of about 12% [6]. Considering this plant can bloom numerous times throughout

the year, if three harvests are made per year, a total of 360 kg of oil can be produced per year, per hectare.

P a g e | 15

3.6 Grevillea Banksii (Grevillea)

Grevillea Banksii is a resilient, evergreen shrub that typically grows in sub-tropical climates. The shrub is

moderately sized and can survive with minimal rainfall. The shrub grows on free draining soils and features

characteristic red tooth brush like panicles, as illustrated in the figure below. These flowers can bloom

throughout the year and can often grow into small trees possessing a number of primary stems [14].

As seen in Figure 10, the Grevillea has been naturalised in central, eastern Queensland. With its resilience

towards marginal rainfalls, the shrub can be expected to continue to propagate through south-east

Queensland and towards the drier, central regions of Queensland.

Figure 10 - The fruit and distribution of Grevillea Banksii in Australia.

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Cultivation of Grevillea Banksii:

This shrub grows best in light, gritty free-draining soils in areas with plentiful sunlight. The soil should also

possess low levels of phosphates [14]. Furthermore, although this plant may be drought tolerant, in order

to maintain consistent and profitable yields for cropping, deep watering systems should be employed [14].

This plant is grown with the greatest success from trimmed, nursery raised plants. Grevillea can however,

be grown fairly successfully when grown directly from seeding [14]. The seeds seen below are removed

from their fruits which are collected by trimming the brush like panicles once fully matured.

Figure 11 - Seeds taken from a Grevillea Banksii plant.

A total of about 2500 shrubs can be grown in a hectare of land. As this shrub blooms throughout the year,

several harvests can be made on a yearly basis. Per harvest, a Grevillea shrub can yield about 0.5 kg of

seeds, if two harvests are made per year. Thus, per hectare, 2500 kg of seeds can be produced from

Grevillea Banksii shrubs. These seeds contain approximately 15% oil on a unit mass basis, which yields 375

kg of oil per year, per hectare [6].

P a g e | 17

3.7 Elaeocarpus Grandis (Blue Quandong)

With characteristic bell shaped flowers and bright blue fruits, the Elaeocarpus Grandis is a large tree that

grows in sub-tropical rainforests conditions near moist, scrubby water courses. This tree grows at

elevations up to 800 m, with a temperature range of 5 to 35 oC [15][16]. The current and potential

dispersal of Elaeocarpus Grandis is displayed in Figure 12 below. As seen, the areas that this tree currently

grows are within sub-tropical and tropical parts of Queensland. With similar conditions all along the coast

of Queensland and Northern Territory, as well as the northern end of Western Australia, this tree has the

potential to be grown in a large area.

Figure 12 - The racemes of flowers bloomed from Elaocarpus Grandis. On the right, a full grown tree and the current and potential distributions on the bottom left.

Also known as the Blue Quandong, this tree flowers between March and June. The flowers grow off

Racemes as seen above. The distinctive blue fruits that are produced after flowering are about 2-3 cm in

diameter and contain 4-5 seeds [15].

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Cultivation of Elaeocarpus Grandis:

The tree is grown from sowing the seeds; however, it can take up to 12 months before the seeds

germinate. Elaeocarpus Grandis grows rapidly with an ample water supply. This tree grows best on alluvial

soils, but it can also be grown very successfully on various soils derived from basalt [16]. Alluvial soils are

primarily utilised for vegetable cropping which could pose limitations on the propagation of Elaeocarpus

Grandis for oil cropping.

The Elaeocarpus Grandis requires an annual rainfall of 1000-3500 mm and does not cope well with

extended periods without watering. Thus, in order to successfully cultivate this plant for oil cropping,

irrigation systems are necessary. Also, this tree quickly deteriorates in cold climates [16]. Around 350 trees

can be grown per hectare of land [6][15].

The fruits should ideally be picked from the tree upon maturing as this is when they contain the most oil.

Although, as the tree can grow up to 35 m tall, directly picking the fruits from the tree can be inconvenient

or too difficult. Alternatively, the fruits can be collected from the floor once they have dropped off the

tree.

The seeds or entire kernel, seen below, contained within the fruit are easily extracted by peeling away the

fleshy fruit. In a year, a healthy plant can yield about 2 kg of kernels, resulting in 700 kg of kernels per

year, per hectare. The kernels contain, on a unit mass basis, about 38% oil, thus a total of about 270 kg of

oil can be produced per year, per hectare [6].

Figure 13 - Fruit and kernel of Elaeocarpus Grandis.

P a g e | 19

3.8 Ochna Serrulata (Ochna)

The Ochna plant is a small understory shrub that grows in subtropical climates, in particular evergreen or

scrub forests. The tree features short-lived yellow flowers which make way for fruits that droop down

from receptacles [17][18]. This plant grows at elevations up to 800 m; however, it does not cope well in

cold climates [18]. The current and potential dispersal of Ochna Serrulata is displayed in Figure 14 below,

along with images of the flowers, fruit and shrub.

Figure 14 - The Ochna Serrulata shrub, with its yellow flowers and the fruits produced. In the bottom right, is the distribution of the shrub in Australia.

The fruits seen above mature and fall off the tree by early summer. As seen, these fruits grow off

receptacles yielding 5 or 6 fruits on each. The fruits themselves contain around 8 seeds each of which are

about 8 mm long. Thus from any receptacle, around 40-48 seeds can be obtained [17].

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Cultivation of Ochna Serrulata:

This is a slow growing shrub that, for purposes of cultivation, requires regular watering. The shrub should

receive a plentiful amount of sunlight and cannot withstand droughts [17]. This drought intolerance is

illustrated in the distribution map on the previous page; the potential distribution only reaches up to the

central coast of Queensland as beyond this point, extended periods without rainfall are expected.

Ochna Serrulata must be grown from direct seeding, where the seeds must be planted as soon as they are

gathered [17]. The shrub grows to a height of 1-3 m and takes up a surface area of about 4 m2. Thus, in a

hectare, up to 2500 plants can be grown [6][18]. The fruits should be collected once they have dropped

off of the plant (during the beginning and until the middle of summer).

The seeds extracted from the fruits, and seen below, are removed simply by squishing the fleshy fruit and

consequently squeezing out the seeds. These seeds contain approximately 30% oil. Each shrub produces

about 0.4 kg of seeds in a year, which totals to around 1000 kg of seeds per hectare, per year. With 30%

oil content, just over 300 kg of oil can be produced per year, per hectare [6].

Figure 15 - Seeds produced by an Ochna Serrulata shrub.

P a g e | 21

3.9 Brachychiton Bidwilli

Brachychiton Bidwilli is a perennial plant, usually classed as a shrub but can grow into a small tree. It grows

in dry rainforests and along various coastal regions, such as along central and southern Queensland [19].

This plant generally grows on free-draining soils, but can grow on other variants of sand, loam, clay or

gravel soils [20]. This is a fairly resilient plant that can cope with droughts and has the potential to be

grown throughout Australia [19]. The current and potential distribution of Brachychiton Bidwilli is

presented in Figure 16 . The shrub or tree, flowers in late summer or early spring, after which, the fruits

mature between March and May. Each of the fruits produced contain a number of hairy seeds [19].

Figure 16 - Brachychiton Bidwilli, its current distribution and its potential distribution in Australia.

P a g e | 22

Cultivation of Brachychiton Bidwilli:

Best grown from direct seeding, as opposed to being grafted from nurseries, this large shrub grows up to

4 m tall and 3 m wide. Approximately 2700 plants can be grown in a hectare [6]. Brachychiton Bidwilli

grows best in sand or clay soils and requires minimal maintenance [20]. Although this plant can survive

without regular rainfall, to maintain consistent yields, it should be supplied with a constant supply of

water. Furthermore, the acidity of the soil must be within a pH of 6.5-8.5 [20].

This plant can grow in partial shade and in mixed cultures as an understory plant. Due to its tolerance to

dry conditions and capability of growing in mixed cultures, Brachychiton Bidwilli holds a wide propagation

potential. As mentioned, the fruits produced mature between March and May. These fruits should be

collected by picking them from the tree during this time; they can still be collected from the ground if they

have already dropped off. The seeds are extracted from the fruits by breaking them apart once they have

dried. As seen in the figure below, the fruits have a hard shell which splits open, revealing the hairy seeds

within.

Figure 17 - The dried fruit and seeds within of a Brachychiton Bidwilli shrub/tree.

A healthy shrub or tree can produce up to 0.6 kg of seeds in a year, totalling to about 1600 kg of seeds per

hectare. The seeds have an oil content of 15%, yielding just over 240 kg of oil at most, per year, per hectare

[6].

P a g e | 23

3.10 Koelreuteria Formosana (Chinese Rain Tree)

The Chinese Rain tree is a moderately sized tree growing up to 18 m tall. Formally known, Koelreuteria

Formosana, this tree typically grows in temperate climates, however it can tolerate a range of conditions

allowing it to be grown in a range of ecosystems [21]. Such conditions range from frost to high heats and

from well-drained to wet soils. Koelreuteria Formosana has also been observed to grow well in areas with

high levels of air pollution [21]. The potential distribution of this plant in Australia is illustrated below.

Displayed in Figure 18 below is a Koelreuteria Formosana tree and the fruits it produces. These fruits grow

from February to March and mature by mid-year. The fruit grows in drooping clusters and grows to about

50 mm in length [21].

Figure 18 - The current and potential distribution of Koelreuteria Formosana, the fruit it bears and a full grown tree.

Cultivation of Koelreuteria Formosana:

P a g e | 24

As mentioned, this tree can survive under a fairly wide range of conditions, however, it thrives in warm

climates under full sunlight. Also, this tree can thrive on a number of different soil varieties, but ideally,

the soil should be free-draining [21]. As Koelreuteria Formosana is drought tolerant it has low watering

requirements.

This tree can be successfully grown from direct seeding or transplanting from nurseries. It can grow up to

18 m tall once fully grown and requires little maintenance. Furthermore, Koelreuteria Formosana can be

grown in mixed cultures. On a per hectare basis, about 400 trees can be grown.

The seeds taken from Koelreuteria Formosana are spherical in shape and have a diameter of around 5

mm. These seeds can be seen in Figure 19 below and contain an oil content of about 22% per unit mass

[6]. The fruits that the seeds are drawn from can be collected from the tree upon maturing or gathered

from the surrounding area as they drop off.

Figure 19 - Seeds extracted from the fruit of a Koelreuteria Formosana tree.

P a g e | 25

3.11 Santalum Album (Sandalwood)

Sandalwood, formally known as Santalum Album, is a medium sized hemi-parasitic tree that grows to a

height of 8 m. Sandalwood grows in subhumid, low-land wet or dry tropics, hence why it is found along

the more coastal regions of the Northern Territory, as seen in Figure 20 [22]. This hemi-parasitic tree can

survive extended periods of drought when attached to suitably drought tolerant host plants. Also seen in

the figure below is the fruit produced by this tree. Santalum Album has two fruiting seasons; the heavy

fruiting season is from December to February and the light fruiting season is from January to March. These

fruits are urn shaped and grow in small clusters [22]. The fruits are red when ripening and turn a deep,

dark purple once fully matured.

Figure 20 - The Santalum Album (or Sandalwood) tree, its current distribution in Australia and the small clusters of fruit produced.

P a g e | 26

Cultivation of Santalum Album:

Being a parasitic plant, it requires a host plant in order to grow and flourish, especially during

establishment. It is grown with greatest success by transplanting from nurseries. Santalum Album grows

on self-draining, light to medium textured soils with full sunlight. Each plant needs a total area of around

4x5 m, accommodating 500 trees per hectare [6][22].

In order for this plant to flourish, it requires a warm to hot climate, having a mean temperature of 23-27 oC. Santalum Album has low watering requirements of 1250-1750 mm annually and can survive periods

of drought of around 5-6 months in length, so long as the host plant is appropriately selected. As such,

once established this plant has very little maintenance or upkeep requirements [22].

The fruits yielded are collected once they have fully matured. The matured fruits can be collected by

trimming the small clusters off the tree or by simply collecting them off the surrounding floor. The fruits

are about 7 mm in diameter and contain a single seed. The seeds are extracted by removing the soft flesh

of the fruit after they have been dried. The dried fruit and seeds within can be seen in the figure below.

Figure 21 - The dried fruit and seeds contained from Santalum Album.

A healthy, mature tree can yield around 40 kg of seeds in a year. Thus, with of 500 trees per hectare,

20000 kg of seed can be produced per year, per hectare. The seeds obtained have an oil content of around

25%, providing a total of 5000 kg of oil per year, per hectare [6].

P a g e | 27

3.12 Argemone Mexicana (Mexican poppy)

Argemone Mexicana, seen in Figure 22 below and commonly known as Mexican poppy is an herbaceous

species which is considered as a weed in Australia. This small shrub, usually growing to 1 m tall, is found

in great number in Western Australia [23]. The shrub grows in pastoral areas such as along or near river

beds, on moist flats and on sand dunes. Occurring mainly in regions with a pronounced dry season and on

open waste grounds, this plant has, as seen below, an extremely large potential distribution through

Australia [24].

The Mexican poppy has two fruiting season in the year; the first being during summer and the second

throughout autumn. The fruits have an ovoid shape and a large number of spikes or prickles as can be

seen in Figure 23 [24].

Figure 22 - The current and potential distribution of the Mexican poppy and a fully grown shrub.

P a g e | 28

Cultivation of Argemone Mexicana:

This shrub is grown best by sowing seeds just below the soil surface at a depth of around 3 mm. Sowing

should be done in late spring and to ensure success, the soil should be moist with a temperature around

25 oC [24][25]. As mentioned, Mexican poppy is often found on open waste lands, hence this shrub can

grow well on soils with low fertility. Furthermore, this plant grows best under full sunlight [24].

Being drought tolerant, this plant has very low annual rainfall needs, however extensive weed

management is a necessity. This plat cannot survive in mixed cultures and quickly deteriorates in the

presence of other weeds [24]. To add to this, the Mexican poppy is a poisonous plant and thus, plantations

must be made away from sources of wheat and other feed stocks so as to avoid contamination [23].

The shrubs are small and only need 1x0.5 m blocks, giving up to 20000 plants per hectare [6]. In a year, a

healthy shrub can produce between 40 and 90 fruits. The fruits seen below can contain about 400 seeds

each. These seeds are spherical in shape and possess a diameter of about 1 mm [25]. The seeds can be

collected by picking the fruits, once matured, off the tree, allowing them to dry and then cracking open

the shell. Alternatively, the seeds can be separated from the entire plant, as the whole shrub can be

harvested and dried.

With 20000 plants per hectare, 40-90 fruits per plant and around 400 seeds per fruit which have a weight

of approximately 0.006 g, a total of 2100-4200 kg of seed can be produced per year, per hectare. The

seeds have, on a unit mass basis, 24% useful oil, providing an annual yield of 540-1080 kg of oil, per hectare

[6].

Figure 23 - The fruit produced by an Argemone Mexicana plant and the seeds contained.

P a g e | 29

3.13 Petalostigma Pubescens (Quinine bush)

The Quinine bush is usually a small tree, growing to typically 3-4 m tall. The tree is found in great

abundance throughout the central highland areas of Queensland. It has also been found in great numbers

through the coastal soils of both Queensland and the Northern Territory [26]. The current distribution of

Petalostigma Pubescens is displayed below. Considering its already large dispersal and the different

conditions in which the plant has been seen to flourish, this small tree has potential to be propagated all

through Western Australia as well.

The Quinine bush blooms during the winter season, this can however depend on the region the plant is

grown [26]. The fruits produced turn orange in colour upon maturing. The fruits can be seen beside the

distribution map, in Figure 24 below.

Figure 24 - A full grown shrub with matured fruits and the current distribution of Petalostigma Pubescens.

P a g e | 30

Cultivation of Petalostigma Pubescens:

Petalostigma Pubescens can be easily grown from either direct seeding without the necessity of sowing

treatments or by transplanting plants from nurseries. As seen by its large dispersal, this plant can tolerate

a wide range of soil conditions. Furthermore, it can also tolerate a variety of conditions from minimal

annual rainfall to tropical conditions. Petalsostigma Pubescens, however, does not cope well with frost

and colder conditions [26].

The Quinine bush has been found to flourish even with partial shading, making it ideal for establishment

as an understory plant [26]. The small tree or bush is rather small and so, a total of about 3300 plants can

be grown per hectare [6].

The orange fruits of the Quinine bush are about 2-4 cm in diameter and contain around 10 seeds in each.

A typical tree or bush produces a fairly large quantity of fruits, yielding around 0.4-0.5 kg of seeds in a

year. The fruits should be picked directly from the tree before fully maturing [26]. The fruit has a tough

outer skin which should be dried thoroughly and then peeled away. An example of the dried outer skin of

one of these fruits can be seen in Figure 25.

Figure 25 - Peeled back dry skin of a fruit from a Petalostigma Pubescens plant, revealing the endocarp.

As mentioned, a typical tree or bush can yield about 0.4-0.5 kg of seeds in a year. Thus, with 3300 plants

per hectare, 1300-1650 kg of seeds can be produced per year, per hectare. These seeds have an

approximate 21% oil content, which results in 270-350 kg of oil, per hectare, per year [6].

P a g e | 31

3.14 Brachychiton Acerifolius (Flame Tree)

Brachychiton Acerifolius, the Flame tree (see below), is a medium sized tree reaching a height of 30-35 m,

although in colder climates it is typically much smaller. The tree features spectacular floral displays after

hot and dry periods [27]. Brachychiton Acerifolius is a hardy plant that can grow in a range of soils and

thrives in temperate to tropical climates. This tree is wide spread through subtropical rainforests from

northern New South Wales and all the way through Queensland, as seen in Figure 26 below [28].

The Flame tree flowers in late spring to early summer. The fruits following flowering have a capsular shape

and leathery texture. These fruits are large and contain 10-15 seeds [29].

Figure 26 - The current distribution of Brachychiton Acerifolius in Australia, a fully blooming tree and the large fruits produced.

P a g e | 32

Cultivation of Brachychiton Acerifolius:

This plant is best propagated from seeding and does not require any form of pre-treatment. The tree can

grow in a large range of soils including heavy clays and sand. It may take however, 5-8 years before a tree

will begin flowering. Alternatively, plants can be grafted using scions from well flowering, mature plants.

Grafted trees flower much earlier than those grown from direct seeding [30].

The Brachychiton Acerifolius is tolerant to both dry conditions and heavy rainfall. It can cope with

droughts, however, it does not deal well with colder temperatures. To add to this, the tree is not tolerant

to harsh or salty winds. Furthermore, the tree does not deal well with medium to high levels of salinity

[30].

For cultivation, trees should be spaced 4x3 m apart, accommodating just over 830 plants per hectare. In

a year, a healthy tree can produce around 2 kg of seeds [6]. These seeds are extracted from the fruit by

allowing the fruit to dry and cracking open the outer shell. Care should be taken when collecting the seeds

as they can cause irritation. The fruits should be picked from the tree when they turn a coppery brown

colour.

Figure 27 - Seeds extracted from a fruit of the Brachychiton Acerifolius.

The hairy seeds seen above contain 20% oil. Thus, with 2 kg of seed per plant and 830 plants per hectare,

a total of around 330 kg of oil can be produced per year, per hectare [6].

P a g e | 33

3.15 Jagera Pseudorhus (Jagera)

Jagera Pseudorhus (see Figure 28) commonly referred to as Jagera is a tall shrub or small tree reaching 6-

10 m in height that usually grows in well-developed highland and mountain forests. In Australia, Jager

occurs from north-eastern Queensland to north-eastern New South Wales as seen below. This shrub

flowers between April and May, giving way for a large number of fruits. These fruits feature fine hairs (see

below) that can irritate the skin [31][32].

Figure 28 - Jagera Pseudorhus, its fruits and the current distribution within Australia.

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Cultivation of Jager Pseudorhus:

Jager grows very well in open fields and is planted from fresh seeds. To ensure successful germination the

seeds must be planted as soon after collecting them as possible. This plant can be adapted for a wide

range of free-draining soils and climate conditions, as evident from its large dispersal. This shrub or tree

can also tolerate partial shading, however it responds best to full sunlight [32].

The Jager Pseudorhus is fairly drought tolerant but, for cultivation purposes regular watering is necessary

[32]. The small tree or shrub occupies about 4x3 m of land allowing for just over 830 plants per hectare

[6]. In regards to harvesting, the fruits are fairly large and easy to collect from the tree directly. Care should

be taken when gathering the fruits due to the irritating hairs surrounding them. Each fruit contains a

number of small seeds seen in Figure 29. The seeds are taken out of the fruits by simply peeling open the

relatively tough outer layer.

Figure 29 - Seeds produced by Jagera Pseudorhus.

A healthy shrub can produce around 0.5 kg of seeds in a year. This results in a total of 415 kg of seed per

hectare, per year. The seeds have a useful oil content of 34% totalling to a yearly oil yield of 141 kg per

hectare [6].

P a g e | 35

3.16 Ricinus Communis (Castor Oil Seed)

Ricinus Communis (see Figure 30) is a moderately sized shrub that grows to 1-4 m tall. Growing mainly in

riparian habitats such as along water courses and flood plains, this shrub has been declared as a weed for

its rapid propagation and resilience to a number of unfavourable conditions [6][33][34]. The Castor oil

seed shrub is drought tolerant and can flourish in range of temperatures from 7 oC to 28 oC [35]. Due to

its survivability, Ricinus Communis has a very large dispersal through Australia, as illustrated below.

Flowering occurs during late spring and early summer with the fruits being produced by late summer.

Although, Ricinus Communis can bloom throughout the year depending on the conditions, summer is the

main period [34].

Figure 30 - Ricinus Communis, the seeds produced and its current and potential distribution through Australia.

P a g e | 36

Cultivation of Ricinus Communis:

This plant is grown from seedlings, which require a rich soil along with daytime temperatures above 20 oC

[35]. The shrub grows best in well-drained, moisture retentive clays or sandy loam, under full sunlight.

The shrub also prefers high temperatures and humidity [35]. Not only is the plant drought tolerant but it

can also grow in soils with high levels of salinity. In addition, Castor oil seed can tolerate short periods of

sub-zero temperatures [36].

Being a weed, Ricinus Communis can grow very well in mixed cultures and in partial shading, allowing it

to be grown as an understory plant for trees possessing minimal foliage. Ricinus Communis should ideally

be spaced 2x1 m for cultivation purposes, accommodating 5000 plants per hectare [6].

A typical healthy shrub can produce a total of about 0.2 kg of seeds in a year. This results in approximately

1000 kg of seed per hectare, per year [35]. The fruits are easily harvested by picking them directly from

the shrubs or simply collecting them from the surrounding area. The seeds are then taken out of the fruits

by cracking them open. This can be done almost immediately after being picked as they are already dry

by the time they are picked. Care should be taken when collecting the seeds as they contain ricin, a potent

poison.

Figure 31 - Seeds produced by Ricinus Communis.

The seeds gathered (and seen above) have a high oil content of about 50% per unit mass. Thus, with 1000

kg of seed, 500 kg of oil can be produced per year, per hectare by Ricinus Communis [6][37].

P a g e | 37

3.17 Atalaya Hemiglauca (Whitewood)

The tree seen in Figure 32 is known as Whitewood, a small tree reaching to about 6 m in height. Formally

Atalaya Hemiglauca is a very drought tolerant tree growing throughout the open plains and alluvial flats

of the central regions of Australia as seen below [38]. Atalaya Hemiglauca flowers from spring until early

summer. This tree produces a large quantity of fruits that resemble propeller blades [38]. These fruits (see

below) contain around two or three seeds in each.

Figure 32 - The current distribution of Atalaya Hemiglauca, a full grown tree and the fruits yielded.

P a g e | 38

Cultivation of Atalaya Hemiglauca:

The Whitewood tree is easily grown from seedlings in a wide range of soils seen throughout central

Queensland and Northern Territory [38]. It can also be transplanted from nurseries. This tree requires full

sunlight and grows best on coarse sands or clay loams. As mentioned, it is highly drought tolerant and can

also tolerate light frost [38].

This is a fairly small tree, occupying 3x2 m blocks, allowing approximately 1660 trees per hectare [6]. The

fruits can be collected by picking them directly from the tree. In a year, a healthy tree can produce about

2 kg of seed; this results in 3320 kg of seed per hectare, per year [6]. The seeds themselves may be too

inconvenient to be taken out of the fruits due to the tight containment of the seeds. Instead, the entire

fruit can be dried and used. Below is an image of the dried fruit.

Figure 33 Fruits produced by Atalaya Hemiglauca.

The Whitewood seeds contain around 15-20% oil on a unit mass basis. Thus, with 3320 kg of seed per

hectare, per year, a total of around 500-650 kg of oil can be produced [6].

P a g e | 39

3.18 Dianella Caerulea (Blue Berry Lily)

Dianella Caerulea is an herbaceous shrub growing to a height of about 0.5-1.3 m, commonly referred to

as the Blue berry Lily for the characteristic purple berries [39]. The soft blue flowers bloom during spring,

followed by the berries [40]. The Blue berry Lily can be found on the east coast of Australia from Torres

Straight island to Tasmania and is most common through New South Wales [39]. A dispersal map of this

plant through New South Wales is displayed below along with an image of the blue flowers.

Figure 34 - Dianella Caerulea, its flowers and a distribution map for New South Wales.

P a g e | 40

Cultivation of Dianella Caerulea:

The Blue berry Lily is easily propagated via direct seeding in a wide range of environments. This plant is

known as one of the hardiest plants, tolerating droughts, frost, high humidity and heat [41]. Furthermore,

Dianella Caerulea, can flourish in partial shading and as it grows amongst grasses, it is a suitable

understory species [41].

Once established very little maintenance is required, however, slow release fertilizer should be used every

spring or just before the flowering season [41]. For cultivation purposes a spacing of 1x0.5 m should be

employed, accommodating a total of 20000 plants per hectare [6]. In a year, a typical plant will produce

around 0.11 kg of seed. The seeds can be collected by stripping the stalks that they grow off. The collected

fruits should be either dried or fermented before extracting the seeds.

Figure 35 - Seeds produced by Dianella Caerulea.

The seeds seen above contain about 19% oil. Considering a plant yields 0.11 kg of seed per year, in a

hectare up to 400 kg of oil can be produced [6].

P a g e | 41

3.19 Pongamia Pinnata (Karanja)

Growing in the north eastern and central regions of Australia, Karanja is a moderately sized tree growing

up to 15-25 m tall [42]. The tree prefers humid and sub-tropical environments with an average

temperature of 27-38 oC. Pongamia Pinnata has been noted to have an annual rainfall requirement of

500-2500 mm [42]. With the relatively high mean temperature the dispersal of this plant is fairly limited

as seen in Figure 36.

The fruits produced by Pongamia Pinnata grow in clusters as seen below. These fruits feature a pod like

nature with a tough outer shell; they also mature by January-February and contain a number of small

seeds [42][43].

Figure 36 - Pongamia Pinnata, a cluster of the pod fruits and a map of the trees current distribution.

P a g e | 42

Cultivation of Pongamia Pinnata:

Karanja is easily cultivated by sowing the seeds in most soil types. The seeds require no pre-treatments

and germinate anywhere between seven days and one month after sowing [42]. Karanja can grow under

either full sun or partial shade and responds well to regular watering [44]. During the first year of growth,

weed control is necessary [42]. Due to nitrogen fixing properties, Pongamia Pinnata requires very little

care once it has been established [42]. As this tree does not deal well with weeds, it is not suitable for

mixed cultures. Trees should be spaced 5x5 m, which is equivalent to 400 trees per hectare [43].

The fruits should be collected once mature directly from the tree. The bunches of fruit are easily collected

by cutting the main stems connecting to the branches off the tree. The fruits are then dried so that the

pods can be cracked open easily, revealing the seeds (see below). Mature trees can yield 8-24 kg of seed

per year [42].

Figure 37 - Seeds produced by Pongamia Pinnata.

Per hectare, a total of 3200-9600 kg of seed can be yielded per year. The seeds contain, on a unit mass

basis, 22% oil. Thus, 700-2200 kg of oil can be produced per year, per hectare of Pongamia Pinnata [6].

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3.20 Cocos Nucifera (Coconut Palm)

Thought by many to be one of the worlds most useful plants, the Coconut Palm cultivated throughout

the world for different reasons, such as food, wood, handicrafts and others [45]. Formally known as Cocos

Nucifera, the tree grows to about 20-22 m tall and prefers warm, humid tropical or subtropical climates

[45]. Cocos Nucifera typically grows in areas with an average temperature of 27 oC and an annual rainfall

of 1500-2500 mm, such as along the central coast of Queensland [45][46].

Fruit is produced throughout the year at regular intervals. The fruits grow in clusters of about 10 coconuts

and each tree can have a number of clusters at any one time. In a year, a mature tree yields 50-80 fruits

[45][46]. The clusters of fruit can be seen alongside a dispersal map below.

Figure 38 - Full grow Cocos Nucifera trees, the bunches of fruit produced and the current distribution in Australia.

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Cultivation of Cocos Nucifera:

Cocos Nucifera is grown from planting the seeds just before they fully mature and right after they have

been collected [45]. This palm is very adaptable, being able to be grown in almost any soil type so long as

waterlogging does not occur within 1 m of the surface [45]. The plant is also tolerant to salt sprays and

medium to high levels of salinity such as in coastal sandy soils [45][46]. Furthermore, the Coconut Palm is

one of the few trees that can withstand cyclonic winds.

During the first few years of growth manure should be regularly supplied to ensure good growth and high

yields [46]. The tree also responds well to regular watering. Once established little care is required to

maintain the health of this plant. These trees can last up to 50 years producing consistent yields each year

so long as they are taken care of appropriately [45][46]. For cultivation purposes, trees should be spaced

7.5x7.5 m apart allowing for up to 180 plants per hectare [46].

The fruits are best collected before maturing by climbing up and cutting down the bunches of fruits. The

fruits can be collected from around the tree once they matured; however, there is the risk of other

coconuts falling during collection [46]. The part of the coconut used to extract oil from is the copra (flesh

of the fruit). In order to get the copra, the fruits thick outer husk must be broken open. The large seeds

inside must also be cracked open, following which, the copra can be ground away from the hard shell of

the seed.

Figure 39 - A cracked open coconut revealing the white copra within.

A healthy tree produces around 35 kg of seeds per year [46]. Each seed contains about 50% oil on a unit

mass basis, meaning each tree yields 17.5 kg of oil in a year. So, per hectare approximately 3150 kg of oil

can be produced per year [6].

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4. Discussion & Evaluation of the Viability for use as a Biodiesel Feed-

Stock

At the onset of the preceding section (Section 3) the key aspects that define what makes a plant species

viable as a biodiesel feed-stock were presented. They are: the environments in which they can be grown,

specific cultivation requirements, in particular harvesting of the seeds or kernels, and the costs associated

with the various aspects of the oil production process.

In order to determine whether a plant species is viable depends greatly upon where, for what purpose

and how the plant species is grown and used. Though much of what determines a plant species to be

viable is relative to a number of external factors, there are generic aspects, properties and requirements

that apply to any plant species in any situation. Such aspects include the application of fungicides,

herbicides, pesticides and other similar maintenance necessities which depict part of the core productivity

requirements. To add to this, the ecosystems to which a plant is suited can be compared and contrasted

irrespective of external factors. Furthermore, the seed or kernel and oil yields per year and the

corresponding requirements for harvesting the seeds or kernels constitute the primary factor to be

considered, as they have implications for productivity requirements and potential gains.

Thus, the base criteria that the plants will be evaluated with are:

1) Seed yields

2) Oil yields

3) Ease of Cultivation

4) Ease of Harvesting

5) Range of Ecosystems in which they can survive

4.1 Harvesting & Potential Yield Analysis:

On the ensuing page is a graph depicting both the yearly oil and seed or kernel yields per hectare. Several

implications can be gained from this graph. Firstly, the seed or kernel yields for each plant grant insight

into the amount of work, energy and cost needed to harvest the seeds or kernels; the greater the seed

yield, the greater the work, energy and cost needed. Conversely, the seed/kernel yields also help illustrate

the productivity, in particular the output, of each plant species. As seen from Figure 40, Santalum Album

clearly has the highest work and energy input due to its 20000 kg seed yield per hectare, per year. To add

to this, Santalum Album has the highest harvesting and processing costs based on the seed/kernel yields.

Examining the yields of Pongamia Pinnata, it can be seen that it also has a relatively high seed yield and

thus work and energy input requirement. Again, due to its relatively high seed yield, it has one of the

greater productivities. From the larger seed yield, a comparatively higher oil yield can be expected,

resulting in a higher rate of work and output.

The oil yields reinforce implications drawn from the seed yields. As expected, both Santalum Album and

Pongamia Pinnata have relatively high oil yields due to their high seed yields. Although, looking at Cocos

P a g e | 46

Nucifera, it can be seen that while it has a slightly lower seed yield, it has a much greater oil yield than

Pongamia Pinnata. This demonstrates that Cocos Nucifera has a higher productivity than Pongamia

Pinnata; the former provides more than double the output for more or less the same input. Thus, the

difference between the seed/kernel yields and the oil yields provides a quantitative means of comparing

the productivities of different species irrespective of external factors.

Figure 40 - Graphical Representation of the Oil and Seed or Kernel Yields.

Figure 41 compares the oil content per unit mass of each plant, which helps illustrate the comparative

analysis of the plant species productivity. In much the same way that Cocos Nucifera has a higher

productivity than Pongamia Pinnata, both Calophyllum Inophyllum and Aleurites Moluccana have greater

productivities than Santalum Album, even with its superior seed yield, due to their much higher oil

contents. To add to the productivity, a basic cost-benefit comparison can be made. A plant such as Syagrus

Romanzoffian has a much greater cost-benefit than Brachychiton Bidwilli as both plants have similar seed

yields and hence work, energy and cost requirements however, Syagrus Romanzoffiana has a much

greater oil yield (more is being gained for every bit that is going in). So, a high oil yield with a comparatively

low seed yield, such as Cocos Nucifera, would maximise the productivity and thus the cost-benefit.

Following this, from Figure 41, Aleruties Moluccana, Calophyllum Inophyllum and Cocos Nucifera hold the

greatest viability, closely followed by Santalum Album and Pongamia Pinnata.

0

5000

10000

15000

20000

25000

We

igh

t (k

g)

Comparison of Oil Yields Per Hectare, Per Year

Seed Yields

Oil Yields

P a g e | 47

0

10

20

30

40

50

60

Oil

Co

nte

nt

Pe

r U

nit

Mas

s (%

)Oil Content of Each Plant Species

Figure 41 - A comparison of the oil content by mass.

P a g e | 48

4.2 Cultivation Analysis:

The preceding discussion has revealed a number of plants are superior based on their productivity and

cost-benefit, as evident from seed/kernel and oil production. Appendix i contains the primary information

relating to the cultivation requirements of the plant species. Due to the previous discussion, five plants

were highlighted as they had the most significant oil and seed/kernel yields and that this implied that they

also have a higher productivity. This however, does not draw any connections from either the specific

cultivation requirements of each plant or the costs of collecting and processing the seeds/kernels.

As seen from Table 1, both Calophyllum Inophyllum and Aleurites Moluccana, though they grow in a large

number of different soil conditions and a fairly wide range of climates, neither can be grown very well in

the more central regions of Australia. On the other hand, plants such as Atalaya Hemiglauca, Argemone

Mexicana and Ricinus Communis can be grown almost anywhere in Australia; particularly Ricinus

Communis and Argemone Mexicana as they can both be grown on infertile waste lands. Most of the plant

species studied currently grow along the east coast through Queensland and many reaching down into

New South Wales.

Looking back at Figure 41, it can be seen that Argemone Mexicana has the sixth highest oil and seed yields

per hectare, per year, making it a very versatile plant that can provide a moderate productivity. Looking

at Santalum Album and referring back to the map in Figure 20, this plant grows in a very limited region,

primarily due to its hemi-parasitic nature. So, although this plant has one of the highest oil yields, it has

limited propagation. Similarly, Elaeocarpus Grandis grows best on alluvial soils, which poses severe

limitations on its propagation as alluvial soils are widely used for vegetable crops.

Another factor to be considered is the collection of the fruits from the plants and the difficulty of

extracting the seeds or kernels. Many of the plants yield small soft fruits which can be easily picked by the

bunch off the plants and then squashed revealing the seeds. On the other hand, there are many fruits or

seeds such as those from Calophyllum Inophyllum or Aleurites Moluccana that have tough endocarps and

so must be dried thoroughly in order to retrieve the desired raw product. Another such example is

Brachychiton Bidwilli which has fruits featuring a tough outer skin. Although some fruits need to be dried

out in order to gain the seed or kernel there is not much difference in the work required. The only concern

is with Argemone Mexicana and Ricinus Communis. Argemone Mexicana fruits feature large prickles and

a tough skin making both collection of the fruits and extraction of the seeds a potential risk, requiring

additional work relative to other plant fruits, while Ricinus Communis fruits contain a potent poison, ricin.

Furthermore, plants such as Syagrus Romanzoffiana and Cocos Nucifera are harvested by the bunch from

their respective trees. This makes collection of the fruits very easy. Once again, the fruit from Calophyllum

Inophyllum and Aleurites Moluccana are picked one by one making for a much more laborious harvest.

P a g e | 49

A final deliberation must be made on account of the costs associated with the plant species. There are

many costs that cannot be predetermined without knowing specific details about where the plant is to be

cultivated (external factors) however, in Table 1 is a column that contains the wholesale costs of the seeds

per kg. This cost provides great insight into the ease of fruit collection and cultivation of the plants; lower

costs imply wide spread cultivation of the plant and demonstrate greater productivities. This however,

does not take into consideration that many of the plants under consideration have never been cultivated.

Nevertheless, from these costs, Cocos Nucifera, Aleurites Moluccana and Syagrus Romanzoffiana have

the lowest seed costs which clearly demonstrate the wide spread cultivation of these plants and the ease

of harvesting, particularly so with Cocos Nucifera costing less than 1 AUD per kg when bought in bulk. The

costs range up to 1633 AUD per kg of seed for Elaeocarpus Grandis.

Thus, based on the above considerations, Cocos Nucifera, Atalaya Hemiglauca, Aleurites Moluccana,

Callophyllum Inophyllum and Syagrus Romanzoffiana possess the greatest viability. Cocos Nucifera,

Aleurites Moluccana, Calophyllum Inophyllum and Syagrus Romanzoffiana, can all be grown along the

coast of Queensland and the Northern Territory and if provided with sufficient watering (or irrigation) can

be grown towards the more central regions of Australia. It should also be noted that both Cocos Nucifera

and Calophyllum Inophyllum are two of the only plants that can withstand cyclonic winds.

The above conclusion does not include the possibility of mixed species plantations. Many of the smaller

shrubs and trees can grow in partial shade as understory plants allowing for the cultivation of multiple

crops at once. This may alter the yields of each plant due to the sharing of resources and minerals and

would