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Background

Once the harvest of peat from a bog has been

completed, restoration is an important step in its

management. The goal of restoration is to re-establish

an ecosystem with the same ecological functions as

the original bog, that is to say a wetland dominated

by typical bog plants and accumulating peat.

In the absence of restoration efforts, harvested sites

remain denuded or become colonized by forest or

agricultural plants. Without appropriate intervention,

bog plants become re-established slowlier or not

at all.

guide_restauration_final_EN.indd 1 13-08-20 14:43


3

This guide describes the six steps of bog restoration:

1 - Planning p. 4

2 - Preparing the land p. 8

3 - Collecting plant materials p. 14

4 - Spreading the Sphagnum moss p. 18

5 - Spreading the straw p. 20

6 - Blocking drainage p. 22

Fertilization p. 23

Monitoring p. 24

Budget p. 26


44

1 Planning

Restoration of peat bogs involves a considerable

investment of human and monetary resources. In order

to obtain the expected results in the field and stay

within the budget, the restoration project must be

planned at the earliest possible stages of production

on the site; that is, the restoration plan should be

established as soon as exploitation of the bog begins.

Purchasing straw• The price of straw varies greatly from year to year and from re-

gion to region. It is thus a good idea to stock up on straw when prices are low, and plan for transporting the straw in advance, if necessary. It may also be advantageous to order straw from a nearby farmer a year in advance.

• If straw is stockpiled in advance, it must be kept dry to avoid spoilage.


55

Restoration work• Restoration operations involve a lot of movement of machinery

in the post-harvest areas to be restored and in the natural areas used as donor sites. It is thus crucial that the machinery be able to move easily without sinking into the surface. When the ground is too soft, the costs of the restoration project skyrocket (see Budget section, p. 26–27).

• Collecting plant materials and spreading the Sphagnum mosses and straw can be done when the ground is still frozen in early spring.

• The restoration activities should be included in the plans for the company’s normal operations in order to manage the availability of machinery and manpower. It is best to restore large areas to reduce the cost per hectare and facilitate rewetting of the restored site.

It is preferable to carry out restoration work shortly after

harvesting operations have ceased, in order to slow

the decomposition and oxidation of the remaining

peat. However, it is also preferable to restore large

areas that can be efficiently rewetted rather than

small areas for which rewetting may be incomplete.

Hence the importance of planning the sequence of

opening and closing the fields and integrating these

processes into the plans for the company’s operations.


66

The chances of successful restoration of the site will be

increased by certain conditions:

• Acidic residual peat (pH 5.1 or less) with a low to medium level of decomposition (H5 or less on the von Post scale).

• Large enough to be efficiently rewetted or isolated from areas still being harvested with respect to drainage.

• Source of good quality plant material readily available in suffi-cient quantities.

• Not adjacent to fields still being harvested, because dust from harvesting impairs regrowth of Sphagnum mosses

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Conducive to restoration

Not conducive to restoration

pH Scale

Strongly acidic Acidic Neutral Basic Strongly

basic


77

H1: Undecomposed: structure of plants unaltered; yields clear, slightly brown or yellowish water when squeezed.

H2: Almost undecomposed: structure of plants distinct; yields clear, slightly brown or yellowish water when squeezed.

H3: Very slightly decomposed: structure of plants distinct; yields slightly turbid, yellow-brown water when squeezed; no peat extruded between fingers; resi-due not soggy.

H4: Slightly decomposed: structure of plants distinct; yields very turbid water when

squeezed; no peat extruded between fingers; residue rather soggy.

H5: Moderately well decomposed: structure of plants still evident but becoming difficult to identify; yields turbid brown water when squeezed; some peat extruded between fingers; residue very soggy.

H6: Well decomposed: structure of plants indistinct but more evident than in the residue; about one third of peat sample extruded between fingers.

H7: Strongly decomposed: structure of plants indistinct but some still identifiable; about half of peat sample extruded between fingers.

H8: Very strongly decomposed: plant structure very indistinct; about two-thirds of peat sample extruded between fingers; residue almost entirely composed of tough root fibres and wood.

H9: Almost completely decomposed: hardly any identifiable plant structures; almost all the peat sample extruded between fingers.

H10: Completely decomposed: no identifiable plant structures; all the peat sample extruded between fingers.

Blond peat

Brown peat

Peat humus

Marshy woody peat

Reed and sedge peat

Mud

Mineral subsoil

Von Post Scale

H1

H2

H3

H4

H5

H6

H7

H8

H9

H10


88

2 Preparing the land

Re-profiling fields

Site preparation begins with using a levelling auger

(leveller) to modify the surface profile of the harvested

peat fields, which typically have a convex, domed

shape.

This step is essential for three reasons: • The convex shape promotes rapid drainage of peat fields to

facilitate harvest. For restoration to be successful, the fields must be flattened so that the water will be evenly distributed.

• Sphagnum mosses need a lot of water and low mineral content to grow well. Exposing the mineral subsoil should thus be avoided. Flattening the fields also helps create an even layer of residual peat, spreading it toward the edges of the fields, where there is usually less remaining peat.


9

Branch leaves

Branches

The water rises in the branches through capillary action

Crust formation

• The levelling auger can also freshen the surface and reduce the amount of surface crust. Good contact between fresh residual peat and the introduced Sphagnum mosses is essential, because the new plants obtain water through capillary action.


1010

If the land is not flat, it may be advantageous to

create berms or dikes during site preparation, and

to fill the secondary drainage ditches with peat.

On sloping sites, creating berms or dikes perpendicular

to the slope helps spread water over the site and

reduces the extent of areas that are either too flooded

or too dry.

Berms and drainage


1111

The drainage ditches can be filled using an auger

and a grader.

This step is even more important if the ditches have

become colonized by herbaceous plants. Filling

the ditches helps eliminate the undesirable plants,

which might otherwise compete with the regrowth of

Sphagnum mosses and other bog plants.

Undesirable plants

If the restoration site has been retired from production

for some time, undesirable plants may have become

established in the fields and drainage ditches. These

plants should be eliminated either with the levelling

auger or by repeated passes with a harrow, followed

by the levelling auger.


1212

Pools

Pools can contribute to the biodiversity of the restored

bog. Although there are no set rules on what form

such pools should take, here are a few useful tips:

• A rectangle approximately 6 to 8 metres wide, 12 to 15 metres long, and 1 to 2 metres deep is the easiest to create using machinery and is large enough to provide habitat for many wildlife species.

• The pool should be deep enough (1–2 m) to hold water during dry summer months, but it is important that any excavation not reach the mineral subsoil.

• To provide varied habitat, one bank of the pool should be gently sloping and the other should be steep.

• Finally, it is a good idea to include partially submerged materials (e.g., tree trunks with branches) in pools to encourage colonization with diverse species.

If the secondary drainage ditches do not reach the

mineral subsoil, they can be left as is or widened,

turning them into elongated pools.

6 to 8 m

12 to 15 m

1 to 2 m


1313


1414

3 Collecting plant materials

Choosing the donor site

If you plan on opening a new peat bog, make

plans to use the surface vegetation as donor

material to restore retired sites.

The donor site must have plants that are

appropriate for bog restoration, namely abundant

Sphagnum and Polytrichum mosses (see Practical

Identification Guide, pages 18 and 22). The choice

of a suitable donor site is a critical factor for the

success of the restoration project. The donor site

must be accessible, sparsely wooded and as close

as possible to the restoration site to reduce

transportation costs.

To estimate the required size of the donor site, use a

1:10 ratio as a rule of thumb. That is, it is estimated

that fresh surface vegetation collected from 1 m2 is

sufficient to spread over 10 m2 of the restoration site.


1515


1616

Harvesting of plant material

Once the donor site is selected, it is measured and

marked out with stakes and ribbons. The surface

vegetation is then shredded to a depth of no more

than 10 cm using a rotovator. Only the top 10 cm is

used for several reasons:

• The fragments of Sphagnum mosses in the top 10 cm have the best regenerative potential, whereas it is best to avoid the deeper, decomposing fragments.

• This limits the impact on the collection site, allowing it to recover more quickly.

• The hummock-forming Sphagnum mosses (i.e., Sphagnum fuscum and S. rubellum) are the most suitable for restoration.

Once the material is shredded, it is picked up with a

mechanical shovel or front loader to be transported

close to the restoration site. If the material cannot be

spread the same day, it must be piled up to keep it

from drying out.


1717

SPHagnUM FUSCUM

SPHagnUM RUBellUM Gill

es

Ayo

tteG

ille

s A

yotte


1818

4 Spreading the Sphagnum mosses

The plant material is usually spread using a manure

spreader (rear- or side-discharge). It is critical that

the right amount of Sphagnum moss fragments be

spread, covering the ground with a continuous thin

layer, 1 to 2 cm thick, without clumps.

The fragments of fresh vegetation should be in close

contact with the remaining layer of peat to ensure

that the Sphagnum moss does not dry out.

As much as possible, avoid creating ruts on soft

ground and do not drive over the freshly spread plant

material.


1919


2020

5 Spreading the straw

The freshly spread fragments of vegetation would be

exposed to harsh conditions unless protected with

mulch. Oat straw is often used because its long stems

provide adequate protection and good results.

The straw should form a layer of air above the ground

to keep the Sphagnum mosses cool and moist while

allowing enough light to penetrate to encourage

plant growth. If too thick, the layer of straw can

smother the plant fragments and interfere with esta-

blishment of the new vegetation, so using the right

amount is important. For each hectare of the restora-

tion site to be covered, the recommended amount

is 3,000 kg of straw, the equivalent of 20 large round

bales (5 feet in diameter).


2121

The straw should be spread at the same time as

the Sphagnum moss fragments, preferably using a

side-discharge bale processor. Driving machinery

over the newly spread plant fragments is not

recommended, so the straw should be spread

after every two or three passes of the manure

spreader, depending on how far the bale processor

blows the straw. Driving over mulched surfaces

causes less damage than driving over the exposed

Sphagnum moss fragments.


2222

6 Blocking drainage

Adequate water is essential to successful restoration,

so blocking drainage ditches is crucial and should be

done properly.

Take the following precautions to ensure that the

blocking dams are watertight:

• Use moist, well-decomposed peat (i.e., peat harvested from a fairly deep level).

• Remove all vegetation on both sides of the ditches.

The blocking dam must:

• be compacted with heavy equipment,

• be 2 to 3 metres wide,

• be higher than the surrounding ground surface.


23

It is best to wait until the very end of the restoration

work before blocking the drainage ditches, even if

doing so results in driving on a small planted area,

because once the ditches are blocked the ground-

water level can rise quickly, which would interfere

with completion of the rest of the work.

Fertilization

In some cases, fertilization can increase the chances

of the restoration succeeding. When a site has

undergone frost heaving of the peat layer, an

application of 15 kg per hectare of granular rock

phosphate during the summer following the

restoration work is recommended. This can be done

using an all-terrain vehicle equipped with a fertilizer

spreader. Rock phosphate stimulates the rapid

growth of Polytrichum mosses, which help stabilize

the ground surface.


2424

Monitoring

Restoration is not always completely successful on the

first try, so the restored site should be monitored for a

few years (1 to 5 years) after completion of the initial

work.

• In the first year, hydrological wells can be installed to monitor the level of the water table. Ideally, it should be less than 20 cm below the surface. If the water table is too low, the restoration will be compromised. To correct the situation, the blockage of the drainage ditches should be checked and modified where needed.

Stopper with attached cord

Fastener

Water level gauge

PVC pipe, perforated over its entire length

Nylon stocking

Height of the water table


25

• In the second or third year, the Sphagnum and Polytrichum mosses that are becoming established on the site can be seen. The presence of bog species should be monitored by setting up quadrats. Early in the restoration, the main species of interest are Sphagnum mosses, so quadrats measuring 25 X 25 cm are adequate. The plant species present in each quadrat are inventoried and the total area covered by any vegetation is estimated. The area covered by species grouped by vege-tation strata (Sphagnum spp., liverworts and brown mosses, heaths, grasses, trees and shrubs) is also estimated. A plant inventory should be made once a year, at the end of the growing season. The progress of the restoration should also be documented with photographs.

Regrowth of vegetation after one year.


26

Time devoted to each operation (in hours):

Operation 2010-2013 Industry Projects Average Preparing the land 7.3 4.1

Collecting 12.7 12.2 plant material

Spreading 9.6 6.6 the Sphagnum

Spreading the straw 6.6 6.1

Blocking drainage 1.5

Total hours per hectare 37.7 29.0

Budget

The budget data presented in the following tables

was compiled from two sources. The “2010-2012

Projects” data are derived from restoration work

carried out as part of the projects coordinated by the

Peat Moss and Agri-Environmental Cluster, whereas

the “Industry Average” data are taken from a report

commissioned by Environment Canada*.

* Golder Associates, March 2012. Évaluation des coûts

de la restauration des tourbières au Canada.


27

Cost of restoration operations:

Operation 2010-2013 Industry Projects Average Preparing the land $635 $306

Collecting $1,079 $863 plant material

Spreading $902 $489 the Sphagnum

Spreading the straw $422 $465

Blocking drainage $138

Other expenses $894 $1,362

Total cost per hectare $4,070 $3,485

Key points for restoration cost reduction:

• Plan the work (purchasing straw, collecting plant material, preparing the site when the ground is frozen, etc.).

• Plan for restoration well in advance, so that large areas can be restored at the same time.

• Equipment operator training and supervisor experience (information regarding goals and objectives).

• Conservation and monitoring of a well-located collection site.

• Use of appropriate machinery.

• As weather conditions can affect the restoration activities, allow some leeway in the work schedule so that each operation can be carried out at the right time.


2828

acknowledgements

This document was prepared as part of the implementation of the action plan of the Peat Moss and Agri-Environmental Cluster of the ACCORD program and its financial partners, Canada Economic Development for Quebec Regions and the Ministère des Finances et de l’Économie du Québec.

We are grateful to the photographers who contributed images, especially Gilles Ayotte, and to the editors and reviewers of the text, Stéphanie Boudreau, Geneviève Potvin and Rémy Pouliot.

Author: Marlies Hähni, project manager, geographer, M.Sc. Environmental Science.

Partners

Canada EconomicDevelopment for Quebec Region s


Peatland Restoration - Operations Manual ©2013

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cover EN.indd 1 13-08-20 15:50€¦ · residual peat and the introduced Sphagnum mosses is essential, because the new plants obtain water through capillary action. guide_restauration_final_EN.indd