What is Silviculture? Silvics + Culture

Transcription

1 What is Silviculture? Silvics + Culture

2 What is Silviculture? Principles vs Practices Art and Science of directing forest establishment, composition and growth ---- (Smith Textbook) Cultural treatments involved in controlling establishment, growth, composition & quality of forest stands for one or more objectives timber, wildlife, recreation, watershed, aesthetics, soil stabilization, etc.

3 What is Silviculture? The art of producing and tending forest stands by applying scientifically acquired knowledge to direct forest establishment, growth, quality and health Applying different treatments to make forests more productive or useful to landowners and society on a sustainable basis

4 The art and science of directing the establishment, growth, composition, health, and quality of forest stands to meet the objectives of the owner/manager and society on a sustainable basis.

5 CONCEPTS Nothing more than applied ecology A set of tools to accomplish the goals of the owner/manager Just as valid for wildlife habitat, watershed, & recreation management as for timber Has biological, economic, and social aspects Silviculture is a decision-making process

6 Ecology Social Economic Silviculture

7 Silviculture Definition Terminology Art and Science Summary Directing forest establishment, composition, health, growth & quality Objective(s) of the landowner Integrating ecology/biology, economics and social aspects (sustainable basis)

8 Purpose Make forests permanently useful to mankind ---- sustainable Create & maintain a forest that will best fulfill the objectives of the landowner To improve or modify on nature or to restore ecosystems --- influencing growth, composition, and structure of stands. How do we do this???

9 Purpose How accomplished? 1. Control of stand composition 2. Control of stand density 3. Intensive cultural practices

10 Purpose Why necessary? ---- time & money Avg. rate of production of US forests is 39 cubic feet/acre/yr ---- includes poorlystocked, degraded and slow producers Contrast with a southern pine plantation to 250 ft 3 /acre/yr Through silviculture we could easily double the rate of production to 75 ft 3 /acre/yr

11 Silviculture and Other Aspects of Resource Management Silviculture & its relation to biology, harvesting, management & economics What you do in one area will influence all other areas of management --- integrated Relationship of Forests to Stands to Individual Trees --- appreciation of scale!

12 Silviculture Vs. Forest Management Silviculture --- Biological aspects of forestry --- stand is the unit of consideration Forest Management --- Business end of forestry --- includes financial & economic considerations --- unit is the forest

13 Management Terminology Stands --- biological unit, contiguous group of trees sufficiently uniform in species composition, age classes & conditions to be a homogeneous & distinguishable unit. Any silvicultural treatment is likely to affect all trees in the same manner

14 Management Terminology Forest --- management unit, a collection of stands. The unit for sustainability is the forest, not the stand --- Stands may be used in obtaining a sustained yield cut from the forest

15 Economics Main reason why you cannot make a silvicultural decision based solely on biological grounds Economics will (should) influence your silvicultural decision. Will often limit or determine them. Long term investments ---- risk? Usually several silvicultural operations (pathways) will accomplish the objectives, but economics of that operation will probably determine which one is used

16 In Silviculture We are managing: Sunlight Stand Density or Spacing Utilizing Site Productivity

17 % Sunlight Small Opening Size Large Selection Shelterwood Seed Tree Clearcut Shade Tolerant Species Shade Intolerant

18 Stems per Acre 6 inches trees 8 inches trees 10 inches trees 12 inches trees 14 inches trees 18 inches trees 20 inches 30 to 50 trees

19 Silviculture Is not cookbook Infinite variation --- Components??? Must be able to think & assess situation and be able to improvise, apply the basic knowledge that I hope you obtain from this course to more complicated situations in the field

20 Silviculture More than fiber production In many cases, other uses may be the more valuable product of the forest We can not under-emphasize any product of the forest on social or economic grounds Total resource management, not just vegetation management ---- ENVIRONMENT

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26 Subject Matter of Silviculture 1. Stand Establishment ---- Regeneration 2. Intermediate Operations 3. Harvest Cutting 4. Protection

27 Establishment Protection

28 Succession Orderly replacement of communities (textbook definition from Clement) Annuals >>> Perennials >>> Shrubs >>> Saplings >>> Poles >>> Sawtimber Pioneers >>> Intermediates >>> Climax

29 Succession Why do we rarely reach a climax stage?

30 Succession Why do we rarely reach a climax stage? Disturbance (both natural and mancaused) is rampant on the landscape Through silviculture we influence succession by controlling the environment through cutting in all its forms

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32 Source: National Weather Service

33 Source: Kim Coder, University of Georgia Average Number of days with thunderstorm events each year

34 Succession Generally, we manage and promote the earlier stages of succession WHY?

35 Succession Pioneers Intermediates Climax Intolerant Tolerant Fast-Growing Slow-Growing Light-Seeded -----usually----- Heavy-Seeded Short-Lived Long-Lived Natural Pruners Limby Will not Reproduce Will Reproduce in Own Shade in own Shade

36 Succession Autogenic Succession --- colonization, alteration of the environment, displacement of species Allogenic Succession --- occurs after a disturbance --- usually sets succession back to an earlier stage Rate of Succession

37 Succession Autogenic Succession --- colonization, alteration of the environment, displacement of species Allogenic Succession --- occurs after a disturbance --- usually sets succession back to an earlier stage Rate of Succession Species Early vs. Late Succession Environment Climate & Site Productivity

38 Why Does Succession Occur???

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40 Developing Wildlife Habitat Components Accomplished by controlling stand structure and forest structure Stand structure --- ages, sizes and density within a stand --- i.e., diversity Forest structure --- sizes and spatial arrangement of stands within the forest

41 Developing Wildlife Habitat Components Browse Herbaceous Vegetation (herbage) Hard and Soft Mast Shelter / Cover All occur at different stages of stand development

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43 Developing Wildlife Habitat Components Importance of Vertical Stand Structure Birds --- feeding and nesting Diversity in single-aged, single-species stands vs older, mixed species stands Through silvicultural treatment can create older stages of canopy structure. How?

44 Developing Wildlife Habitat Components Importance of Modifying Stand Structure Species Composition Sizes and Spatial Arrangements Edge vs Interior Corridors

45 Developing Wildlife Habitat Summary Components Wildlife Travel and Move Create Diversity of Vertical & Horizontal Habitat Structure Delineation of stands of different characters to compose the entire forest habitat

46 Developing Wildlife Habitat Summary Components Habitat Diversity is the KEY, through manipulation of different stand structures, both horizontal and vertical structure. Populations vs individual wildlife species

47 Silvicultural Systems and Methods of Regeneration System vs Method Regeneration vs Reproduction Classification of Regeneration Methods origin, form, and size/geometry of cut

48 Silvicultural Systems and Methods of Regeneration Even-aged system Clearcut Seed Tree Shelterwood Two-aged system Uneven-aged system Group Selection Single-Tree Selection

49 Silvicultural Systems and Methods of Regeneration What determines even-aged vs uneven (multi-age) form? 1. Height Differences (crown class) 2. Competition 3. Diameter Distributions (graphs) 4. Geometry & Size of Cut

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51 Choosing a Regeneration Method With most species, we have choices as to the method that we use. WHY? Factors 1. Desires of the owner 2. Biological Considerations 3. Economics ***

52 % Sunlight Small Opening Size Large Selection Shelterwood Seed Tree Clearcut Shade Tolerant Shade Intolerant

53 Summary So what are we doing in managing a forest? Initiate disturbances generally to satisfy an objective(s) Influence structure and species composition of regenerating stands Manage structure and understory composition to provide desired conditions in the future