Stephen G. Boyce Southeastern Forest Experiment Stat Ion
Total Page：16
File Type：pdf, Size：1020Kb
United States Department of Agriculture Forest Service Stephen G. Boyce Southeastern Forest Experiment Stat ion General Technical Report SE-35 GOAL FOR MANAGEMENT / 1 Management Actions 2- 1 ENVIRONMENT \ 0' \- 1 Inventories 4' ---.---,-- _ (Sensors) December 1985 Southeastern Forest Experiment Station 200 Weaver Boulevard Asheville, North Carolina 28804 Forestry Decisions Stephen G. Boyce Chief Forest Ecologist, Retired U.S. Department of Agriculture, Forest Service and Adjunct Professor of Natural Resources School of Forestry ar;d Environmental Studies Duke University Durham, North Carolina Contents Chapter Preface ...................... vii Acknowled~roent .................. ix 1 Introduction The Homan Use of Forests ............ 1 The New Direction ............... 7 Decision and Control .............. 9 Complexity ................... 21 2 Structure of the Decision and Control System Overview .................... 25 Control Loop .................. 25 Decision Loop ................. 26 Cybernetic Foundation ............. 30 Negative Feedhack Loop ............. 33 Feed-Forwa rd Loop ............... 31 Positi ve Feedback Loop ............. 39 Cybernetic Structure for Directed Systems ... 42 Concept of Dynamic Plans ............ 48 3 Ecosystem Dynami cs Overview .................... 51 An Operational Def~nitio~of Ecosystems .... 53 Three Elements of Ecosystem Dynam~cs ...... 56 Continuity ................. 56 I rreversi bi 1 ity ............... 57 Structure .................. 57 Four Btonornic Theor~cs ............. 59 Ind~v~ dual ist1 c Systems ........... 59 Or-yanlzation of Forest Commu~lt7es ..... 68 Flows of Energy and Materials ........ 72 Mu3tipleBenefits .............. 7G Validat~onof the Blon~micTh~or~cs ...... 78 Hypothesis for Falsifrcatson of Theor~es.... 79 Xndlv~dualisticTheory ........... 79 Organization Theory ............. 79 Flow Theory ................ €3:) Vu'tlple ReneF~ts Theory .......... 8G 4 Silvicultural Applications OVPTVIPW .................... 81 Rir,qomc Theories That Underlie S~lv;c~i'it.ure. 81 Steady-State and a R~qulatedForest ..... 84 Sustained Benefrts ............. 85 Selective Mortal~ty............. 87 Ei01 oqi ca 1 Potent 3 a l ............ 89 Rate of Tlrnher Harvest ............. 91 S~ngleRotatloq Perrod ........... 92 Superimposed Yotat 1 or Per1 ods ........ 94 Size of Openiqgs .............. 96 !P-Place Eqhancerne~ts ............. 97 Tl?~rln~ngs.................. 9,Q Changes IR Genotypes and Type Ccrvcrsions . 9lt: iii Natural Regeneration .............. 99 Relation of DYNAST Model to Regeneration Systems ................. 101 Selection Regeneration System ........ 102 Group Selection Regeneratron System ..... 103 Shelt~rwnodRegeneration System ....... 104 Seed-Tree Regeneration System ........ 104 Clearcut Regeneration System ........ 105 Translating Information into Management PI ans . 106 Complexity of Planning ........... 107 Co~straintof Complexity .......... 10Y Translation Process ............. 109 States of Forest Organization Ov~rview.................... 113 Organization and Structure Re1 ated to Benefits and Impacts ........... 113 An Algorithm for Timber ............ Ilh Potential Timber Index (PTI) ........ 121 Meaningfi~!ness of PTI ............ 1'24 Limiting Complexity ............. 124 Small Openings Affect the PTI ........ 127 PTI Projections ............... 129 Water Yield Algorithm ............. 132 Sediment Movement Algorithm .......... 138 Habitat Algorithm for a Game Species ...... 142 Habitat Algorithm for a Nongarne Spec1t.s .... 149 Use of Forest Organization in Management Goals . 153 Cash Flows From SI 1vi cul ture Overview .................... 155 Prescriptions for Si lviculture ......... 157 Displays for Decisions ............. 159 White Boxes for Silviculture .......... 165 White Boxes for Cash Flows ........... 172 Dynamic Form of Economic Functions ....... 174 Net Present Value .............. 180 Profitability Index ............. 181 Equivalent Annual Rent ........... 181 Realizable Rate of Return .......... 183 Applications to Other Forests ......... 1n7 Dynamic Analytic Silvf cul ture Technique (DY RAST ) Overview .................... 185 System Dynamics Method ............. 186 Definition of the Question ........... 188 System Dynamics Solution ............ 192 White Boxes .................i94 Interdisciplinary Teams ........... 198 A Simple Model ................. 200 Structure of the DYNASf Model Ov~rvi~w.................... 2G3 Frat crr-es .................... 204 Inventory .................. 205 The Big Ivy For~st ............. 205 Travsformatinn of a Hahitat .......... 707 Symbols and Equatrons ............. 210 Trapsformation of a Forest Type ........ 216 DYWAC>T-FAM ................. 270 Familiar Rotat~onRes~rlts .......... 216 lls~of the Negative Feedback Loop ...... 227 Successi on Rates .............. 231) Supplementary lnformat~on.......... 230 Timber Potentla1 ................ 231 Yotentla1 Tlrnber index ........... 231 Timber and R~omassVolumes ......... 234 Variable Rates of T~mber Harvest ...... 235 Cash Flows ................... 236 Net Present Value. NPV ........... 236 Inflow Equations. IN ............ 238 Outflow Equatlovs. OT ............ 239 Exercises .................. 233 Opening Size ................ 240 Values for Initial Inflows and Outflows I . 241 Plantations. Genetically Improved Trees. and Th~nnlngs .............. 241 WBTOB. the Hab~tatMACRO ............ 243 OBTAH. the Forest Type MACRO .......... 247 PTISO. the Tinher and Opecings MACRO ...... 251 Forest Type Sectors .............. 251 Supplementary Information .......... 258 Renef it and Impact lnformat ion ....... 258 Cash Flow Algorithm ............. 250 Program Control s Sector ........... 260 Analytic Silv?culture Controls ....... 260 Sequence of the Sectors ........... 262 Exercises Without Type Convers~on ...... 203 Forest Type Revers~onsand Conversions ..... 264 A Checklist for Silvic"1ture Controls ..... 267 Conservation of Bi01 ogical Oi versi ty Overview .................... 209 Defining Biolog~calDiversity ......... 270 Relation of Divers~tyto Benefits ....... 271 Diversity in Land Management Planning ..... 277 Diversity in tbe Nat iocal Forest Ma~ageme~t Act (NFMA) ................ 281 The Important Points .............. 282 Page 10 The Use of Biologicat Diversity Overview .................... 285 Forest Eudemonjcm ............... 255 Diversity. Eudemonism. and Management ..... 287 The Highlards Example ............. 288 Predatcry Arthropods ............ 213 Discussion of Findings ........... 293 Translation of the Highlands Data ....... 295 Use of Divers~tyto Evaluate Effects ...... 301 Literature Cited ...................... 303 Index ........................... 313 Checklist for Figures and Table .............. 318 Preface Conservation rather than liquidation is the theme of forestry. Scheduled removals of game and timber are for the purpose of having food, shelter, heat, and other benefits in perpetuity, From this theme came the rallying phrases for forestry: "sustained yield,'"%he greatest good for the greatest number ," "mu1 tiple benefits," "even flow," "regulated forests," and "1 iving in harmony with natrlre." The ideals expressed by these phrases are simple and appeal ing; implemen- tation is very difficult* This book describes a new di rection for implementing the theme of forestry. The sched- uling of harvest and culture found so useful is preserved, What is new is the question that leads to decisions and to control of the forests. In- stead of asking, "'How much game, timber, this, and that do we want to produce?," we ask, "'If we do this, what will we have?" Decisions are answers to the questions: Wow will this or that schedule of culture change the forest over time? What monetary returns wif l we have? What will be the stream of benefits? What wi 11 be the potential produeivity of the forest? This simple change in questioning the choice of decisions and the use sf controls changes the way we view a forest* Rather than viewing a for- est as a manufacturing plant putting together timber, game, and other benefits at the will of managers, a forest is viewed as a biological sys- tem that sel f-organizes in response to culture. Control becomes a process of using culture to di - rect the sel f-organizing forces to transform the forest from the present state through a stream of desired future states, Each state of forest or- gani zation provides some combi nation of materi al s for harvest and some physical structure for non- harvestahle benefits. This new direction is the basis for providing game and nongame animals; trees for timber; shrubs and herbaceous plants; and, possibly most impor- tant, conservation of a wide variety of germ plasm for the livelihood of man. This new direction depends on the concept that behavior of complex ecosystems, such as forests, is princi pal ly caused by structure--how the component parts are con- nected. These connections di rect the flows of information, energy, and materials through feed- back loops to integrate the behavior of the sys- tems' elements. The result is a decision and control procedure that crosses forestry disci - pli nes without conf 1i ct . Optimal strategy is derived by subjective decisions determined by insights, vnl ue judgments, experience, and acumen of interested parties. The responsi bi1 it i es of admi nist rators are not usurped in mathematical expressions; mental models and scientifical ly derived relationships are communi - cated expl icitly; people make the decisions. Many people