THE SILVICULTURAL SYSTEM

Transcription

1 THE SILVICULTURAL SYSTEM Ralph D. Nyland Distinguished Service Professor - Silviculture Department of Forest and Natural Resources Management SUNY College of Environmental Science and Forestry Syracuse, NY Nyland All rights reserved Use of all or parts of this document prohibited without express consent of Ralph D. Nyland SILVICULTURE... the methods for establishing and maintaining healthy communities of trees and other vegetation.. that have value to people 1

2 whatever the values What silviculturists do... CONTROL establishment, composition, structure, and growth FACILITATE harvesting, management, and use PROTECT sites and trees SALVAGE dead and diseased trees, and potential mortality 2

3 ... controlling natural patterns of stand development to favor a landowner SILVICULTURE works with stands STAND A community of trees sufficiently uniform in composition, constitution, age, spatial arrangement site quality, or other conditions that distinguish it so forming a silvicultural or management entity After Ford-Robertson 1971, Helms

4 So silviculture deals with stands homogeneous in some condition or characteristic Treating one stand at a time the silviculture 4

5 Easily identified on the ground US For. Serv. managed as individual units to enhance the desired values 5

6 After US For. Serv. each according to a unique plan FOREST MANAGEMENT deals with the collection of stands that comprise a forest or some other management unit 6

7 To make the whole forest more useful Integrating silviculture across an entire forest the forest management 7

8 Forest management... Like this... across time and space to serve the interests of people 8

9 But always keep Einstein s observation in mind if we are to solve problems that plague us, our thinking must evolve beyond the level where when we created those problems in the first place. (from McDonough and Braungan Page 165) Thus when planning silviculture and forest management After Urban et al

10 integrated across a compartment and throughout a forest 10

11 always thinking about the landscape with important influences coming from outside to affect our options for managing stands and forests 11

12 and others of the stand and forest dictating what we can contribute to the larger area Remember Hummel (2006) calls this LANDSCAPE SILVICULTURE... developing prescriptions for individual stands, but evaluating them collectively based on objectives for the landscape as a whole 12

13 How to do this the silviculture THE SILVICULTURAL SYSTEM the plan for managing a stand over the long run... the way we control, facilitate, protect, and salvage in a stand To control conditions and enhance the desired values 13

14 THE SILVICULTURAL PLAN the end point of a deliberate problem solving process that starts with the objectives for management THE PROBLEM SOLVING PROCESS: 1. Determine the landowner s objectives 2. Evaluate existing stand conditions 3. Identify the options 4. Quantify the likely outcome of each one 5. Drop unsuitable options 6. Explain the viable alternatives 7. Help the landowner decide 8. Implement the prescription 9. Evaluate the results Nyland

15 REMEMBER - Learn the objectives the rest will follow from your thoughtfulness and creativity for a desirable outcome 15

16 So what does a system involve? ALL SYSTEMS HAVE THREE COMPONENTS after Nyland et al Harvest a means to ALL SYSTEMS HAVE THREE COMPONENTS after Nyland et al

17 in a never-ending cycle Requiring all the critical parts Nyland 2002 SILVICULTURE SEPARATES FORESTRY FROM EXPLOITATION Continuity over time Sustained values The systems differ for three broad groups of stands (Definitions follow Helms 1998, Nyland 2002) 17

18 EVEN-AGED A community of trees having no or only small differences in ages by convention with a spread of ages not exceeding 20% of the rotation length ROTATION the planned number of years between formation of a stand (even-aged) and its final cutting (regeneration) at a specified degree of maturity 18

19 Starting with young ones getting older 19

20 and finally mature Aging with a clear pattern of development through time within a single stand 20

21 and in each even-aged stand across a forest So All trees in a stand regenerated at the same time all developing to maturity together all coming of age at the same time 21

22 Even-aged lodgepole pine SEPARATED IN TIME The silvicultural system for even-aged stands 22

23 With even-aged stands tend when immature reducing the crowding Thinning favors the biggest and best trees to promote their growth 23

24 ... with tending (e.g., thinning) to influence stand development With even-aged stands tend when immature regenerate when mature replacing the entire stand 24

25 like the shelterwood method when an even-aged stand matures One kind of even-aged reproduction method 25

26 ... giving rise to a new even-aged community NEVER do all three at the same time... for EVEN-aged silviculture 26

27 UNEVEN-AGED A community with trees that differ markedly in their ages by convention the spread of ages exceeds 25% of the planned lifespan for an age class each stand having trees of different ages including young trees 27

28 intermixed with an older one and another 28

29 and even another and often more all growing together in the same stand 29

30 but only one reaching maturity at a time with ages and sizes interspersed across a stand 30

31 and in uneven-aged stands across a forest So Parts regenerated at different times young, middle-aged, and old all present each comes of age at a different time 31

32 Uneven-aged lodgepole pine CONCURRENT The silvicultural system for uneven-aged stands 32

33 With uneven-aged stands both tend and regenerate each time Periodically regenerating the mature trees thinning the younger age classes 33

34 SELECTION METHOD... the uneven-aged reproduction method... coupled with tending of the three or more age classes within a stand 34

35 ALWAYS do all three things with EACH entry... for UNEVEN-aged silviculture... concurrent treatments TWO-AGED A community with trees of two distinct age classes separated in age by more than 20% of the life span for each one 35

36 A young age class beneath older trees through time the younger trees develop 36

37 getting bigger and bigger we eventually remove the old trees and thin the remaining age class to regenerate a new one and start again 37

38 like this So Two distinct age classes present great difference in age between the two each comes of age at a different time 38

39 Two-aged lodgepole pine USUALLY CONCURRENT SOMETIMES ALONE The silvicultural system for two-aged stands 39

40 REGENERATE a new age class while TENDING the other... but may TEND separately at intermediate stages At maturity remove the old trees and thin the younger ones 40

41 to regenerate new ones and start again Conceptually, these designations imply at least two important concepts: 1. We apply different KINDS of treatments or interventions at different stages of stand or age class development and these occur in a logical SEQUENCE 41

42 2. To adequately control stand establishment, composition, and development (growth) we must also plan for the proper TIMING of the treatments to insure the sought-after effects TIMING and SEQUENCE as well as KIND We do this through the SILVICULTURAL SYSTEM 42

43 Pursuing the options through silviculture But what about intensity? Financial factors often control intensity the inputs of money, people, and other resources 43

44 J.D. Irving, Ltd. even when using efficient methods to implement the treatments With intensity reflecting the inputs of funds, resources, and technology Appreciable inputs Few inputs 44

45 And remember Stone s advice... And remember Stone s advice... Each site can repay only certain levels of investments Domesticated forest After Stone

46 The better sites support a higher intensity of use and repay with higher returns Careful planning can integrate economic and ecologic factors Look at one model... to highlight the challenges... and the concerns 46

47 THE SILVICULTURE SURFACE... a concept for management CONCEPT DRIVEN INPUTS SILVICULTURE MERE MERE CUTTING CUTTING ECOLOGICALLY IRREVERSIBLE After Nowak, Briggs, Germain, and Nyland 2000 Figure 2-7, in Nyland 2002 But the concept basis likely diminishes like this CONCEPT DRIVEN INPUTS SILVICULTURE MERE CUTTING ECOLOGICALLY IRREVERSIBLE After Nowak, Briggs, Germain, and Nyland

48 THE OBJECTIVE to satisfy the economic benefits but in an ecologically acceptable way Economically viable... ecologically sound 48

49 Yet economic constraints may limit actions CONCEPT DRIVEN INPUTS SILVICULTURE MERE CUTTING ECOLOGICALLY IRREVERSIBLE... keeping you in a limited box So move as high on the silviculture surface as financial and other institutional constraints allow at the moment 49

50 But keep things off the slope CONCEPT DRIVEN INPUTS SILVICULTURE MERE CUTTING ECOLOGICALLY IRREVERSIBLE After Nowak, Briggs, Germain, and Nyland 2000 Exploitation often pushes stands over the edge 50

51 Take care to cause no irreversible ecologic change insuring - trees after trees - stable soils - protected landforms (e.g., intact drainages) Silviculture makes the difference 51

52 Background reading: Chapter 2, in Nyland, R.D Silviculture: Concepts and Applications. Waveland Press. Long Grove, IL 2ed. Sources cited: Ford-Robertson, F.C. (Ed.). 1971, Terminology of Forest Science, Technology, Practice and Products. Multilingual For. Terminol. Ser. No. 1, Soc. Am. For. Wash., DC. Helms, J.A The Dictionary of Forestry. Soc. Am. For. Bethesda, MD. Hummell, S.S Seeing the bigger picture: Landscape silviculture may offer comparable solutions to conflicting objectives. US For. Serv., Pacific NW Res. Stn., Science Findings 85. Koten, D.E Lecture notes. Faculty of Forestry, SUNY Coll. environ. Sci., and For., Syracuse, NY. McDonough, W., and M. Braungart Cradle to Cradle: Rethinking The Way We Make Things. North Point Press, NY. Nyland, R.D., C.C. Larson, and H.L. Shirley Forestry and Its Career Opportunities. McGraw-Hill Book Co., NY. 4ed. Stone, EL Soil and man s use of forest land. In pp. 1-9, Forest Soils and Forest Land Management. B. Bewrnier and C.H. Winget (Eds.). Laval Univ. Press. Ste-Foy, QU. Urban, D.L., R.V. O Neill, and H.H. Shugart Landscape ecology: A hierarcial perspective can help scientists understand spatial patterns. Biosci. 37(2):