Combining ?Naturalness Concepts? with Close-to-Nature Silviculture

Forstw. Cbl. 122 (2003), 421−431 Eingereicht am 1. 4. 2003© 2003, Springer-Verlag Akzeptiert am 6. 10. 2003ISSN 0015-8003

Combining ‘Naturalness Concepts’ with Close-to-NatureSilviculture

Die Kombination der Konzepte der „Natürlichkeit“ mit dem

naturnahen Waldbau

A. H. COLAK, I. D. ROTHERHAM and M. CALIKOGLU

Summary

This paper summarizes key aspects of ‘naturalness concepts’ and their relationships to ‘close-to-naturesilviculture’. For perhaps 20�30 years, associated with concerns over apparently increasing biologicaland ecological problems (floods, avalanches, forest die-back, and other calamities) there has been anincreasing debate in forestry centered on efforts to bring forest and woodland management back tomore ‘natural’ approaches. Conservation and other management in parallel to these arguments areflawed unless based on sound conceptual foundations, and to this end basic principles and conceptshave been developed. ‘Naturalness’ is one such concept. However, whilst this is an important term inhelping to understand the key processes at work it has proved difficult to integrate with ideas of‘close-to-nature silviculture’. This paper explores the issues and proposes more effective integration ofapproaches. Possible ways in which the concept can aid conservation management of woods and forestsare suggested.

Keywords: Hemeroby, natural likeness, nature protection, forest management.

Zusammenfassung

Die vorliegende Arbeit faßt die wichtigsten Aspekte des Konzeptes der „Natürlichkeit“ und derenBeziehungen zum „naturnahen Waldbau“ zusammen. Seit etwa 30 Jahren werden im Forstwesen unterden Eindruck von scheinbar wachsenden biologischen und ökologischen Problemen (Überschwemmun-gen, Lawinen, Waldsterben und andere Umweltkatastrophen) zunehmend Debatten darüber geführt,wie die Waldnutzung wieder „naturnäher“ gestaltet werden könnte. Im Zusammenhang mit diesenDiskussionen wären aber Schutz und Nutzung mangelhaft, wenn diese nicht auf soliden Grundlagenund Konzepten beruhen würden. Solche Grundlagen und Konzepte wurden aber schon entwickelt.„Natürlichkeit“ ist ein solches Konzept. Obwohl dieser Begriff wichtig für das Verständnis der Auswir-kungen von Schlüsselprozessen wäre, erwies es sich als schwierig, „Natürlichkeit“ mit den Ideen des„naturnahen Waldbaues“ zu verbinden. Die vorliegende Arbeit untersucht diesen Problemkreis undschlägt eine wirksamere Einbindung entsprechender Methoden vor. Wege werden aufgezeigt, wie diesesKonzept zur Erhaltung von Gehölzen und Wäldern eingesetzt werden kann.

Schlüsselwörter: Hemerobie, Naturnähe, Naturschutz, Waldbewirtschaftung.

1 Introduction

The general principles and development history of ‘close-to-nature silviculture’ are knownto many managers of woods and forests. However, the specific interactions of the con-cepts and of their associated processes remain somewhat elusive and there are significantdifferences in approaches in the UK, the USA and mainland Europe. Five principlescharacterize the approach (SCHÜTZ 1999[a], 1999[b]): (1) use of local yield potential; (2)silvicultural intervention combining timber use and tending goals; (3) continual renewal;(4) maximizing the use of natural regeneration; and (5) a liberal felling policy. However,there are significant issues when discussing ideas such as naturalness and natural forest.THOMSEN (2001) provides a useful overview of the characteristics of a natural forest. Thishighlights the recent shift in emphasis of management in many forest areas away from aprimary goal of wood production to a more holistic approach embracing richer wildlife

DOI 10.1007/s10342-003-0007-1

422 A. H. Colak, I. D. Rotherham, M. Calikoglu

resources and greater biodiversity. The shift in forest priorities suggests the need for anevaluation of some basic concepts. This might include that of the forest concept itself,the aspects of a forest that are important for key wildlife species, and how the principlesguiding management can be applied in practice. THOMSEN (2001) based this overview onobservations in Denmark and Central Europe. It is also clear that there may be majordifferences between ‘natural forest’, ‘close-to-nature sylvicultural systems’ to make man-aged woodland more ‘natural’, and indeed the practical manifestation of ‘naturalness’ as aconcept. These affect the inter-relationships where they occur between the concepts andreality, and influence the ability of a forester or manager to intervene effectively in chang-ing the way a woodland is developing.

In the UK this shift in thinking is evidenced by publications such as HART (1995) onalternative sylvicultural systems, and HELLIWELL (1999) on the application of continuouscover forestry. These approaches go hand-in-hand with interest in the nature of forestedand wooded landscapes, demonstrated by PETERKEN (1996) with a synthesis of ideas onthe nature and growth of ‘natural’ woods � in Europe and North America. This wasfollowed by the Dutch ecologist FRANS VERA (2000) looking at the relationship betweengrazing animals and forest history in Europe. Both the latter had a huge impact onthinking by professionals, academics and the public in understanding the nature of wood-land. The debate generated in recent years has been enormous. However, in Britain andespecially in middle Europe this has in fact been ongoing for a considerable time. For20�30 years researchers and managers have attempted to resolve issues of the nature andhistory of wooded landscapes, and to seek appropriate methods of conservation andmanagement. The relationship between management history and the contemporary re-source, the tensions between human impacts and traditional management (in medievalcoppice woods for example), and reduced intervention or abandonment of some woodshave all been considered. HARDING and ROSE (1993) presented overviews of so-called ‘pas-ture woodlands’ and the importance of their character and conservation management. Inparticular the impacts of grazing on vegetation and on tree regeneration are considered.Aspects of such ancient treed landscapes such as old, dead wood are noted as being ofhuge importance to many plants and animals. Others such as KIRBY and DRAKE (1993)and SPEIGHT (1989) presented coherent arguments for the value of dead wood resourcesin other types of forest, and note the commonly impoverished nature of modern managedforests and many traditionally managed coppices.

Today the real problem for a site manager is how to put these principles into practice.In this context one of the most important issues is the degree of naturalness of forestecosystems. This is because it is more difficult to practice close-to-nature silviculture in aforest that is significantly modified from its potential ‘natural’ structure (SCHMIDT 1998).There are also on-going debates about natural forest forms, and for example difficultiesin the determination of the causes of semi-open forest areas, perhaps due to large herbi-vore effects or to other natural causes. However, PETERKEN (1996) presents a detailedaccount of the definitions of natural woodland, and this provides a firm basis of theoryfrom which practical management can be derived. In order to address the conceptual andindeed practical issues of defining ‘naturalness’ and the significant problems for boththe theoretician and the pragmatist, PETERKEN explores ideas of ‘Original-naturalness’,of ‘Present-naturalness’, of ‘Past-naturalness’, of ‘Potential-naturalness’, and of ‘Future-naturalness. He also discusses the problems for a woodland manager in that many siteslie in between these types. PETERKEN then introduces the more familiar concepts of ‘semi-natural’ (suggesting a range of from 5�95% naturalness for individual sites), and makingthe point that many different aspects of a forest or wood can be evaluated in terms of its‘naturalness’. In this context he also introduces a seven-point scale of naturalness for past-natural woodlands derived from wood-pasture or wood-meadow, from high forest, andfrom coppice. These concepts are placed in both European and North American contexts.

423Combining ‘naturalness concepts’ …

PETERKEN defines the basic terminology that is applied and sets his ideas within the muchearlier system adopted by THOREAU for a woodland classification with origins based backin 1860.

PETERKENS’ work gives the essential underpinning for the application of naturalnessconcepts or close-to-nature systems to contemporary forestry. In particular he assessesthe roles of natural processes and functioning in forest ecosystems. The question is thenhow to apply these concepts in practice within the theoretical framework. Obviously inforestry practice close-to-nature silviculture is only in part connected to naturalness con-cepts. Many other factors influence the approaches taken. In close-to-nature forestry,stands are grouped and zoned by taking into consideration their ’natural likeness’. Natural-ness as a concept has a more comprehensive scope. It implies ’natural likeness’ but alsoincludes a broader concept called ’hemeroby’. This problem has exposed a serious concep-tual gap in both theoretical background and in practice. Genuine multi-purpose forestmanagement necessitates flexible solutions to integrate silvicultural survey informationand management on a more varied scale than in the past (SCHÜTZ 1999[a]). It is this issuethat the present paper seeks to address.

To help integrate close-to-nature silviculture and naturalness might itself be a part ofsuch a flexible solution. This could involve setting targets to help determine the degreeof naturalness of a forest ecosystem in relation to close-to-nature silviculture. Suggestedtargets are summarized in Figure 1.

Fig. 1. Targets in determining the naturalness levels.

Abb. 1. Ziele zum Bestimmen des Grades der Natürlichkeit.


The approaches may be further complicated by the understanding, viewpoints or needsof the different potential landowners and managers. The desire to develop a more naturalapproach to forest management and structure may be led by conservation-minded organ-izations and perhaps governmental agencies. Their aspirations may be at odds with indi-vidual landowners and commercial managers. This in itself adds a note of urgency to thedebate. If approaches are to have sufficient coherence and achieve real change on theground then a common and shared agenda is needed. To achieve this requires dialogue,and this necessitates clear definitions and conceptual frameworks.

2 Hemeroby and natural likeness

Human impacts affect vegetation in different ways and some of these may occur overhundreds or thousands of years. Resulting from these long-term impacts, ingrainedanthropogenic influences on contemporary vegetation in many areas of the world may beso deep that they seem little modified and even ‘natural’. However, during the MiddleAges and later periods, changing land use practices caused major alterations to bothnatural and semi-natural ecosystems. In this context determination of the degree of an-tiquity or primevalness of forest ecosystems, along with patterns of utilization and arti-ficiality ratios, and assessments of spatial distributions of these are important startingpoints for close-to-nature silviculture. To this end the mapping of zones such as biotopes

Fig. 2. Naturalness of forest ecosystems.

Abb. 2. Natürlichkeit von Waldökosystemen.


becomes important in constructing a forest inventory to help inform and determine man-agement against agreed objectives.

Systems for describing levels of both hemeroby and natural likeness help in assessingthe effects of different patterns of utilization on vegetation (KOCH et al. 1998). THOMASIUS

(1992) suggested that the hemeroby concept may be important in helping the realizationof silvicultural targets in this context.

Concepts and approaches again underpin this process of assessment and of manage-ment. Attempts to determine the naturalness of landscapes and vegetation themselveshave a long history, and this spills over into their influence on management. THOREAU in1860 considered woodlands in terms of their origins, and in 1904 BERNATSKY dividedforests into formations according to impacts directly due to people and those associatedwith grazing of range animals. The term ‘hemeroby’ (from two Greek words ‘hemeros’meaning ‘cultivated’ and ‘bios’ meaning ‘life’) was first used by the Finnish botanist JALAS

in 1955, and was introduced to botanical terminology around twenty-five years ago. It hassince been used in scientific writings as a complementary term for ‘naturalness’. It isuseful as a unifying concept in relation to forest or other land management. As a measureof human influence on ecosystems assessment of hemeroby level can be based on theextent of the impacts of anthropogenic influences. It is used in reference to systems thatare self-regulated under the prevailing conditions (KOWARIK 1988, 1999). An advantage ofthe term hemeroby is that it is used exclusively in scientific literature. It is therefore lesslikely to be confused than is the term ‘naturalness’ (GRABHERR et al. 1997). Natural likenessand hemeroby are often used synonymously although their semantic origins are different(Figure 2).

3 Naturalness levels (Hemeroby classes and natural likeness classes) and

their determination

Hemeroby classes may be defined to indicate differing intensities of cultural effects. JALAS

(1955) was the first to divide the degree of hemeroby into different categories: ‘ahemerob’,‘oligohemerob’, ‘mesohemerob’ and ‘euhemerob’. SUKOPP (1972) added ‘polyhemerob’ and‘metahemerob’. Today, some of these groups are divided into sub-groups as ‘α’ and ‘β’.The hemeroby classes presently used are given in Table 1 following SUKOPP (1972), BLUME

and SUKOPP (1976), DIERSCHKE (1994), PITTERLE et al. (1994[a], 1994[b]), KOCH et al. (1998),JESCHKE and WEGENER (1998), and COLAK (2001). Hemeroby assessment may apply toboth vegetation and to site conditions.

DIERSCHKE (1994) suggests that these hemeroby classes supplement the degree of natu-ral likeness in determining anthropogenic influence on vegetation.

LEIBUNDGUT (1990) described the natural likeness of forest ecosystems as a conditionin which the stand structure remains in a nearly natural state, but with clear anthropogenicimpacts on the species mix and/or age structure. This approach can be developed furtherto give five classes according to natural likeness (Table 2).

The determination of naturalness levels is one of key issues discussed by PETERKEN

(1996). The indicators used in the determination of naturalness level are biotic or abioticcharacteristics (positive indicators) and catastrophic events or disturbances (negative indi-cators). Because of the complexity of naturalness, factor combinations are used insteadof a single factor. It is worth noting, and with the rapid spread of alien species increasinglyimportant, that since exotic species cannot reflect the potential natural state of the area,and are introduced by human activity, they are used as negative indicators (KOWARIK 1999).Criteria for determining the naturalness levels are summarized in Table 3.




Table 2. Determination of natural likeness classes.

Tabelle 2. Bezeichnung der Naturnähestufen.

Natural likeness classes

Natural Naturally formed forests not altered by human directly or indirectly. Potential natu-ral vegetation is dominant.

Near-natural These are forests which are close the natural structure in terms of species mixture(Close-to-natural) and stand composition. There are minor alterations to the vegetation.

Semi-natural Forests partly altered particularly in mixture and stand composition but retainingtheir natural structure. There are obvious deviations from the potential natural vege-tation.

Altered With these forests their natural characteristics are scarcely recognizable, with signifi-cantly altered ecological conditions. The natural potential vegetation is not present.

Artificial Such forests are formed artificially with almost no degree of naturalness. Secondarypine plantations replacing mixed hardwood forest are examples.

Table 3. Criteria used in the determination of naturalness levels.

Tabelle 3. Die zum Bestimmen des Grades der Natürlichkeit verwendeten Kriterien.

Hemeroby classses

Criterion (KOCH et al. 1998, THOMASIUS 1992, GRABHERR et al. 1997)

1. Recent impact of man2. Naturalness of tree composition and ground flora3. Tree species and ground layer species diversity4. Proportion of the neophytes and the therophtys5. Indicator species (plant, animal, fungus)6. State of development7. Forest structures

* Age structure* Species structure* Spatial structure

8. Soil properties9. Type of tree regeneration

10. Amount of dead wood11. Clear-cut areas

Natural likeness classes

Criterion (KÖRPEL et al. 1988, SCHERZINGER 1996)

1. Potential natural vegetation2. Structural richness suited to natural life stages of natural forests3. Forest dynamics4. Self renovation potential (natural regeneration, humification, water economy etc.)5. Species diversity of the flora and fauna

4 Conclusions

There are many issues to debate in terms of the relationships between environmental andanthropogenic factors and their histories in influencing the nature of wooded landscapes.This critical evaluation is important in determining the degree to which semi-natural,ancient woods enclosed and managed for coppice since medieval times, or grazed medie-


val forests, parks and chases, or other pasture woods are indeed ‘close-to-nature’. Thesefactors are discussed by PETERKEN (1996) and VERA (2000), and by other authors. How-ever, the balances between the factors themselves and also their perception, vary dramati-cally across Europe and around the world.

Furthermore, whilst the application of close-to-nature principles is increasingly con-sidered (HART 1995, THOMSEN 2001, for example), the context of the forest industry andits changing demands raises new challenges. There is an increasingly broad spectrum ofsituations in which it is desired to apply these ideas. These range from the recovery ofsemi-natural, broad-leaved woods with twentieth century coniferous planting in England,to the more close-to-nature natural management of working forest in Turkey, and fromplanted new native species woodland in Britain, to planted coniferous forest in the Scott-ish Highlands. In all these situations and more, it is useful to be able to relate close-to-nature sylviculture to the concepts (often abstract) of naturalness.

In this context it is useful that assessment according to the degree of hemeroby canbe applied in many situations where nature and people interact. According to GRABHERR

et al. (1997): ‘In principle the concept of hemeroby is generally applicable and free of anyconnotations’. This approach can be therefore be applied to vegetation science and inecosystem analyses, and in assessments for both nature conservation, and for woodlandor forest management.

For sustainable forest management in particular, the use of hemeroby classes is veryhelpful in guiding management towards close-to-nature silviculture. As noted, natural like-ness is particularly useful in helping to define close-to-nature forest systems. Furthermoreit relates also to hemeroby and through this to the general concept of naturalness. It issuggested therefore that it should be possible to organize and indeed broaden approachesto close-to-nature silviculture through guidance based on considerations of hemeroby.

If it is desired to bring a forest ecosystem closer to its natural potential state, or toconserve its actual state (for example in selecting nature conservation areas, in determiningthe boundaries of less altered ecotopes, or by increased naturalization), then natural like-ness can be a useful tool to this end (SCHMIDT 1997). In some cases it may be that themanagement approaches derived from concepts and indicators of hemeroby or naturallikeness alone cannot meet the targets set. In this case it may be that further criteriaspecific to factors such as species rarity or extinction, and related management prescrip-tions are needed to guide forest work on the ground (KOWARIK 1999).

A problem in determining the degree of forest naturalness is that similar stand types orcharacteristics may be associated with both natural development and with anthropogenicexploitation. Separation and recognition of these in different places and different timesmay be important in understanding forest dynamics. For example, in some circumstancesuneven aged stand structures result from anthropogenic grazing by domesticated animals(KIRBY 1994), and may present as similar to what are actually more natural stands. Similarlyhuman impact may have influenced landscapes and vegetation over very long time-periods,and (increasingly recognized in both Eurasia and North America) and it is unclear howranking according to degrees of naturalness can be effectively applied. KOWARIK (1999)stated that in a forest ecosystem there is a lower level of naturalness if species variationsoriginated through human activities. He concluded that a vegetation type changed byhuman influence to an irreversible degree, or which has for a long time had new species(neophytes) as a consequence of these impacts, could be described as natural vegetation.With this definition a plant community can be considered as ‘natural’ vegetation eventhough it is not in its original unaffected stage. PETERKEN (1996) also gives useful guidanceon classification according to naturalness in terms of history, origin, management andstructure.

If it is desired that a forest is to be managed according to close-to-nature silvicultureprinciples, then maps of naturalness zones, of biotopes, and of key sites will be central to


the process. Forestry activities such as silvicultural conversion, restoration, and close-to-nature silvicultural operations, can be effectively organized using naturalness zone mapsas a guide. With naturalness maps prepared according to hemeroby classes for five- orten-year periods, it is possible to predict human impacts on forest ecosystems, and soinfluence the degree to which close-to-nature silvicultural practices may meet forestrymanagement and conservation targets set. Furthermore, the use of naturalness maps withbiotope maps can assist in the prediction at a landscape scale of any likely variations,deviations or conservation risks. It is argued that these naturalness maps should be pre-pared in the context of the broad issues discussed earlier. In preparing naturalness mapsthe following factors should be taken into account: (1) Natural forest conditions; (2)Relevant natural life stages and processes; (3) Any zones from which management isremoved, and for which only natural successional development is allowed, should becarefully monitored.

Incorporation of recent developments in technology to take full advantage of the powerand precision of Geographic Information Systems, Geographic Location Systems, andportable computers, will further support and facilitate this approach to better informingsite management and monitoring.

Finally it is suggested that this approach helps to give a useful and unifying frameworkto direct management, to assist in setting realistic targets, and in both monitoring andevaluating progress.

6 Acknowledgements

The authors wish to thank Prof. Dr. Peter A. SCHMIDT (Dresden, Germany) for scientificReview and Dr. Josef SENN (WSL, Swiss) for help in preparing the Germany version ofthe manuscript. The anonymous referees are also thanked for their insight and theirhelpful comments.

7 References

BERNATSKY, J. (1904): Anordnung der Formationen nach ihrer Beeinflussung seitens der menschlichenKultur und der Weidetiere. Engler’s Bot. Jahrbuch, 94/1, 1�8.

BLUME, P., SUKOPP, H. 1976: Ökologische Bedeutung anthropogener Bodenveränderungen. SchriftreiheVegetationskunde, Bonn-Bad Godesberg, 10, 7�89.

COLAK, A., H. 2001: Nature Protection in Forest (Terms-Principles-Strategies-Measurements). ForestMinistry. Milli Parklar ve Av-Yaban Hayat? Genel Müdürlügü Yayini, Ankara (in Turkisch).

DIERSCHKE, H. 1994: Pflanzensoziologie. Grundlagen und Methoden. UTB, Grosse Reihe, Stuttgart.GRABHERR, G., KOCH, G., KIRCHMEIR, H. 1997: Bildatlas „Naturnähe Österreichischer Wälder“. Bundes-

ministerium für Land- und Forstwirtschaft, Wien. Sonderdruck zur österreichischen Forstzeitung,1/17, 1�39.

HARDING, P., T., ROSE, F. 1986: Pasture-Woodlands in Lowland Britain − A review of their importancefor wildlife conservation. Institute of Terrestrial Ecology, Monks Wood Experimental Station, Hun-tingdon.

HART, C. 1995: Alternative silvicultural systems to clear cutting in Britain. Forestry Commission Bulletin,115, HMSO, London, 89 pp.

HELLIWELL, R. 1999: Continuous Cover Forestry. Journal of Practical Ecology and Conservation, 3/1, 59�62.

JALAS, J. 1955: Hemerobe und hemerochore Pflanzenarten. Ein terminologischer Versuch. Acta Soc.Fauna Flora Fenn. 72/11, 1�15.

JESCHKE, L., WEGENER, U. 1998: Möglichkeiten und Grenzen des Naturschutzes in der Kulturlandschaft.In: WEGENER, U., (Eds.), Naturschutz in der Kulturlandschaft. Schutz und Pflege von Lebensräumen.Gustav Fischer V., Stuttgart, 456 pp.

KIRBY, K. 1994: Die Bewertung von Wäldern und Gehölzbeständen. In: Usher, M., B., Erz, W., (Eds.),Erfassen und Bewerten im Naturschutz. Probleme-Methoden-Beispiele. Quelle & Meyer V., Heidel-berg-Wiesbaden.


KIRBY, K., J., DRAKE, C., M. (Eds.) 1993: Dead wood matters: the ecology and conservation of saproxylicinvertebrates in Britain. English Nature Science, 7, English Nature, Peterborough.

KOCH, G., KIRCHMEIR, H., GRABHERR, G., REITER, K. 1998: Hemerobie, Österreichischer Waldökosys-teme. Österreichische Akademie der Wissenschaften. Veröffentlichungen des österreichischen MAB-Programms. Band 17. Universitätsverlag Wagner, Innsbruck.

KOWARIK, I. 1988: Zum menschlichen Einfluß auf Flora und Vegetation. Theoretische Konzepte undein Quantifizierungsansatz am Beispiel von Berlin (West). Landschaftsentwicklung. Umweltfor-schung, Berlin, 56, 280 pp.

KOWARIK, I. 1999: Natürlichkeit, Naturnähe und Hemerobie als Bewertungskriterien. In: KONOLD, W.,BÖCKER, R., HAMPICKE, U. (Eds.), Handbuch Naturschutz und Landschaftspflege. Ecomed,Landsberg, 1�18.

KÖRPEL, J., FEICKERT, G., U., SPANDAU, L., STRASSER, H. 1988: Praxis der Eingriffsregelung: Schadenersatzan Natur und Landschaft?, Ulmer V., Stuttgart.

LEIBUNDGUT, H. 1990: Waldbau als Naturschutz. Haupt V., Bern und Stuttgart.PETERKEN, G., F. 1996: Natural Woodland − ecology and conservation in northern temperate regions.

Cambridge University Press, Cambridge.PITTERLE, A., BRESCHAR, R., FUXJÄGER, C., VOITLEITHER, J. 1994[a]: Waldbauliche Maßnahmen im Nation-

alpark „Kalkalpen“-Kernzone. Institut für Waldbau, Wien, 134 pp.PITTERLE, A., ZEHETBAUER, H., FRANK, D., HOLZINGER, A. 1994[b]: Waldbau in Nationalparken.

Wesentlichste Waldgesellschaften und deren Behandlung in Kern- und Außenzonen („Donau-Auen,Thayatal, Kalkalpen und Hohe Tauern“). Eine Studie des Waldbau � Institutes. Universität fürBodenkultur, Wien, 47 pp.

SCHERZINGER, W. 1996: Naturschutz im Wald. Qualitätsziele einer dynamischen Waldentwicklung. Prak-tischer Naturschutz. Verlag Eugen Ulmer, Stuttgart.

SCHMIDT, P., A. 1997: Naturnahe Waldbewirtschaftung. Ein gemeinsames Anliegen von Naturschutzund Wirtschaft? Naturschutz und Landschaftsplanung, 29/3, 75�83.

SCHMIDT, P., A. 1998: Potential natural vegetation as an objective of close to natural forest management?Forstw. Cbl. 117, 193�205.

SCHÜTZ, J.-Ph. 1999[a]: Naturnaher Waldbau: gestern, heute, morgen. Schweiz. Z. Forstw. 150/12,478�483.

SCHÜTZ, J.-Ph. 1999[b]: Close-to-nature silviculture: is this concept compatible with species diversity?Forestry, Vol.72/4, 359�366.

SPEIGHT, M. 1989: Saproxylic intertebrates and their conservation. Council of Europe, Strasbourg, Nat-ure and Environment Series, 42.

SUKOPP, H. 1972: Wandel von Flora und Vegetation in Mitteleuropa unter dem Einfluß des Menschen.Berichte über Landwirtschaft, Band 50, 112�139.

THOMSEN, K. 2001: Characteristics of a natural forest. In: Tools for Preserving Woodland Biodiversity.NACONEX, The Corporation of London, London, 14�19.

THOMASIUS, H. 1992: Prinzipien eines ökologisch orientierten Waldbaus. Forstw. Cbl. 111, 141�155.THOREAU, H., D. 1860: The Succession of Forest Trees. Excursions. Boston and New York, 1906.VERA, F. 2000: Grazing Ecology and Forest History. CABI Publishing, Oxon, UK.

Author’s address: Ass. Prof. Dr. Alper Hüseyin COLAK (Corresponding author) and Dr. Mehmet CALIKOG-

LU, Department of Silviculture, Faculty of Forestry, Istanbul University, TR-34473, Bah-ceköy, Istanbul, Turkey, Tel.: ++90�212�2261100, Fax: ++90�212�2261113, email:[email protected] and [email protected];Dr. Ian D. ROTHERHAM, Centre for Environmental Conservation and Outdoor Leisure,SLM, Sheffield Hallam University, England, Tel.: ++0114�2252874, Fax: ++0114�2252881, email: [email protected].

Documents

Combining ?Naturalness Concepts? with Close-to-Nature Silviculture