ECOSYSTEM (SITE) CLASSIFICATION: PRINCIPLES, CONCEPTS, RATIONALE, SYSTEM, AND ITS DEVELOPMENT; APPLICATIONS IN FOREST RESOURCES MANAGEMENT

Transcription

1 Tullamore, Ireland June 2008 ECOSYSTEM (SITE) CLASSIFICATION: PRINCIPLES, CONCEPTS, RATIONALE, SYSTEM, AND ITS DEVELOPMENT; APPLICATIONS IN FOREST RESOURCES MANAGEMENT K. Klinka Professor Emeritus, UBC Forest Sciences Department, Vancouver, BC

2 Preamble Without classification there can be no science of vegetation (Daubenmire 1959) Without classification there is no science of ecosystems and ecology. And indeed, no science (Krajina 1960) We ought to make full use of what has been already discovered, while endeavouring to find what has not (Unknown)

3 Outline 1. Principles, Concepts, and Rationale 2. Development of Ecosystem Classification 3. The Classification System 4. Application of the Classification

4 1. Principles, Concepts, and Rationale What is ecosystem? How to study ecosystems? How to classify ecosystems? Rationale for ecosystem classification

5 1. Principles, Concepts, and Rationale What is ecosystem? Classification requires that the concept of what is to be studied be defined; different concepts (definitions) would result in different classifications (and confusion) Local ecosystem: a landscape segment relatively uniform in climate, soil, vegetation, animals, and microorganisms

6 A Local Ecosystem

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8 1. Principles, Concepts, and Rationale Vegetation and soils are the most easily studied ecosystem components and thus form the basis for ecosystem classification Local ecosystem; what is the size of local a ecosystem? Ecosystem sampling the sampling of vegetation (sample plot) and soils (pedons) Regional ecosystem: a group of contiguous local ecosystems affected by the same regional climate

9 1. Principles, Concepts, and Rationale If a population of ecosystems in the landscape is very large and the variation within a population is great, we group individual ecosystems that are alike in selected characteristics Classification frames classes of similar ecosystems, and characterizes and names these classes. When there are too many classes, a hierarchy of classes is created Some property must chosen as the basis for grouping differentiating characteristics; it should be associated with a number of co-varying properties, i.e., accessory characteristics

10 1. Principles, Concepts, and Rationale What is the difference between taxonomic and interpretive classifications? Taxonomic classification are developed from bottom to top What are the characteristics of a good classification? Classification organizes ecosystems in way that shows the greatest number of relationships in the most important properties Classification establishes order. Order wherever it reigns, brings intellectual beauty with it (Duhem 1974)

11 1. Principles, Concepts, and Rationale Understanding forest ecosystems means understanding vegetationenvironment relationships and vegetation succession Forest (Ecosystem) management requires ecosystem-specific approach The application of an ecosystem-specific approach requires that a forest be stratified into ecologically uniform segments. In consequence, management of that forest can be simplified and, at the same time, given a sound ecological foundation A consistent and ecological meaningful stratification requires, in turn, an appropriate ecosystem classification system

12 2. Development of Ecosystem Classification - Approaches Environmental approach (soil, landform, and site classification) Vegetation approach (vegetation classification) Combined approach (ecosystem or ecological classification) Developed by V.J. Krajina and his students ( ) who sampled and analyzed ecosystems across British Columbia They considered all useful approaches and concepts of used by Cajander, Braun-Blanquet, Clements, Pogrebnyak, and Sukachev The resulting uniform classification system improved our understanding of vegetation-environment relationships and vegetation succession and provided a framework for ecosystem-specific management in British Columbia

13 V.J. Krajina

14 2. Development of Ecosystem Classification The system was adopted by the BC Ministry of Forests around 1976 The reason for the adoption was providing applicable tools (field guides, indicator plant species, and training) for ecosystem identification and silvicultural decision-making The system gave impetus to develop comparable versions across Canada A modified version of the system (Ecological Site Classification) is used in Great Britain since 2001)

15 3. The Classification System What is biogeoclimatic ecosystem classification? The system that organizes ecosystems according to relationships in climate, vegetation, site quality, (and time). The system includes three independent but integrated classification: climatic, vegetation, and site The system is vegetation driven as plants integrate best the combined influence of numerous environmental factors

16 3. The Classification System Concepts and elements of the system: Site factors that directly affect vascular plants Site quality and ecological equivalence Climate Soil moisture regime Soil nutrient regime Zonal concept Indicator plants Edatopic grid

17 Structure and Hierarchies of the System

18 A topographic sequence showing location of vegetation units along the local climatic, soil moisture, and soil nutrient gradients. A site-specific chronosequence of vegetation units along the time gradient. A section of landscape showing locations of three biogeoclimatic subzones (1, 2, and 3) recognized on the basis of distribution of zonal ecosystems. Each segment features a variety of ecosystems (as shown on the left) where vegetation may be in various successional stages (as shown on the right).

19 3. The Classification System Vegetation Classification Plant orders recognized in coastal BC: Quercus garryana Pseudotsuga menziesii - Mahonia nervosa Tsuga heterophylla - Rhytidiadelphus loreus Tsuga mertensiana Thuja plicata - Tiarella trifoliata Populus trichocarpa Pinus contorta

20 Vegetation Classification - a Pinus contorta ecosystem

21 Zonal Classification - Zones of British Columbia 1. Alpine Tundra 2. Spruce-Willow-Birch 3. Boreal White and Black Spruce 4. Sub-boreal Pine Spruce 5. Sub-boreal Spruce 6. Mountain Hemlock 7. Engelmann Spruce Subalpine Fir 8. Montane Spruce 9. Bunchgrass 10. Ponderosa Pine 11. Interior Douglas-fir 12. Interior Western Hemlock 13. Coastal Douglas-fir 14. Costal Western Hemlock

22 Zonal Classification - Zones of British Columbia

23 Site Classification - Edatopic Grid

24 Site Classification - a Cladina/slope-rocky site

25 Site Classification - a Lysichitum/gleysolic site

26 4. Application of the Classification The system is widely used because it provides the best tool for the application of the ecosystem concept Research carried out in support of the classification and its applications: quantitative characterization of soil moisture and nutrient regimes, shade tolerance, and forest productivity Silvicultural prescriptions identifying sites are legal documents for any crown-land area to be treated The classification has been followed by ecosystem mapping (GIS) The classification provided a framework for a variety of research as well as for portability of knowledge and past experience and research

27 4. Application of the Classification Site Identification 1. Stratify an area into environmentally uniform segments. 2. Identify biogeoclimatic unit (subzone) for each site by locating the site on a large scale zonal map. 3. Estimate soil moisture and nutrient regimes of each site by considering selected environmental properties and indicator plant species. 4. Consider other environmental factors which may influence vegetation and/or management. 5. Identify site unit on the appropriate edatopic grid.

28 4. Application of the Classification Identifying quality of a cutover site

29 4. Application of the Classification - Site Identification Actual vegetation unit: Epilobium (stand initiation stage) Zonal unit: Very Wet Maritime Coastal Western Hemlock (CWHvm) subzone Soil moisture regime: fresh Soil nutrient regime: medium Other environmental factors: zonal Site unit: Hemlock Blueberry/zonal 01/zonal

30 4. Application of the Classification Regional Guides Edatopic grids for the CWHdm subzone upland sites, fluctuating water table sites, and floodplains

31 4. Applications of the Classification - Instructions of Silvics Edaphic amplitude of Populus tremuloides

32 4. Application of the Classification Tree Species Selection Selecting the best tree species for regenerating a forest is a critical management decision. It requires that Ecological characteristics of forest trees, sites and ecosystems are known, and The management intent, strategy, and objectives are defined The criteria adopted for the tee species selection are: Maximum sustainable productivity Crop reliability Silvicultural feasibility

33 4. Application of the Classification Tree Species Selection What is the climatic amplitude of potential species? What is the edaphic amplitude of these species? What is the shade tolerance of these species? What are protection requirements of these species? What is the growth pattern of these species? What is the reproduction capacity of these species? The species (or their combination) are selected that are ecologically viable, conform to the management goals, and fulfil the adopted criteria

34 4. Application of the Classification Climatic Considerations

37 4. Application of the Classification Edaphic Considerations

40 4. Application of the Classification Site Preparation

41 4. Application of the Classification Tree Species Selection Douglas-fir is a protection-requiring on very dry sites

42 4. Application of the Classification Tree Species Selection Western hemlock is to be avoided on very dry, moderately dry, wet sites, and nitrogen-rich sites.

43 4. Application of the Classification Tree Species Selection Western redcedar is to be avoided on very dry and moderately dry sites but favoured on all other sites

44 4. Application of the Classification Tree Species Selection Western redcedar is easy to regenerate by planting but may require protection from browsing

45 4. Application of the Classification Tree Species Selection Second-growth western redcedar stands are rare in the CWHdm subzone

46 4. Application of the Classification Forest Productivity Productivity of crop tree species on different sites is one of the most desirable information for forest management Providing and predicting site indices for all crop tree species for all site units in the province was one of the most important contribution of the classification to forest management (Dr. H. Chen s presentation) Inquiry into productivity of mixed-species stand showed that the growth of structurally stratified mixture of shadeintolerant and shade-tolerant tree species will likely surpass that of single-species stands

47 4. Application of the Classification Forest Productivity Site index of coastal Douglas-fir on coastal sites in relation to site quality trophosequences

48 4. Application of the Classification Forest Productivity Response of coastal Douglas-fir on coastal sites to nitrogen fertilization An edatopic grid showing six site series, pretreatment foliar N (%) and sulphate-s (ppm), and isolines of relative basal area response indicating the third-year basal area response of Douglas fir to fertilization with nitrogen.

49 Conclusions Classification does not increase our knowledge about things; knowledge is only obtained by studying the things Classification provides a logical tool to organize existing knowledge in a way that is easily retained in memory and is easy to convey through instructions A good classification should display intellectual economy of thoughts; i.e., establishing order out of apparent disorder and facilitate perceiving relationships among the things studied