Uncertainty in adaptation to climate change in forest management

Transcription

1 Unertainty in adaptation to limate hange in forest management Emina Krmar 1, Shirley Mah 2, Gordon Nigh 2, Christine Flether 2 and G. Cornelis van Kooten 3 Report from FFESC projet University of British Columbia, Vanouver, BC 2 BC Ministry of Forests, Lands and Natural Resoures Operations, Vitoria, BC 3 University of Vitoria, Vitoria, BC

2 Exeutive Summary The purpose of this study is to develop a oneptual framewor to support deision maing in forest planning under unertainty related to limate hange. There are many possible limate hange senarios, but no single senario an be reommended as the best. This reates onditions of deep unertainty for deision maing. Among various onepts developed to address deision hallenges under deep unertainty, we employ one based on robustness as a riterion for evaluation. Rather than looing for optimal plans assuming that future onditions are nown, the robust approah searhes for good-enough plans under a range of unnown future onditions. For the Quesnel study area, the overall objetive of strategi forest planning is to provide a balane between several ompeteing interests under unertainties related to limate hange. To ahieve this overall objetive, we developed multi-riteria forest planning models that address both a timber supply goal and a diversity-related goal for tree speies in the region. The timber-supply goal was formulated as maximization of a period harvest while maintaining a stable harvest flow over time. The first step in formulation of the diversity-related goal is to define the landsape-level speies omposition targets. In the absene of an established methodology, we define the speies targets in terms of the speies projeted frequeny of ourrene under several limate hange senarios. The eologial goal is then formulated as minimization of an average deviation of the modeled speies frequeny of ourrene from the target speies frequeny of ourrene. In this report we present, assess and ompare the outomes of forest planning models under two renewal options: (i) the status quo option that preserves pre-harvest speies omposition at the landsape-level, and (ii) another that promotes forest resiliene by allowing hanges to the speies omposition. The seond renewal option is introdued in forest management planning as means for adapting to hanging limate. Assuming the status quo renewal option and solving the multi-riteria forest planning model for eah of the individual limate senarios produed a set of alternative forest management plans. Under the onditions assumed, no robust plan was identified. In other words, under the urrent renewal option, there are no forest plans that ahieve both the timber supply and landsape-level speies omposition targets for all of the limate hange senarios onsidered. The examination of riteria values for the forest plans under the status quo renewal option provided insights into limate onditions to whih forest plans were most vulnerable. This examination allows for reduing the initial set of limate senarios. In the next stage, the multi-riteria forest planning model was solved for the individual limate senarios from the redued set under the assumption of an adaptation renewal option that promotes forest resiliene by hanging the landsape-level speies omposition. After analyzing riteria values for the forest plans generated under the adaptation renewal option and the redued set of limate hange senarios, we identified two potential robust plans with riteria values good-enough for all limate senarios from the redued set. Seleting the forest management plan for implementation will depend on other fators that 1

3 are beyond the sope of this projet. Staeholders may request repeating the deision proess with additional and/or different eologial, eonomi and soial goals and riteria. All results of the ase study are valid only under the given assumptions and represent relative rather than absolute values. For example, if the assumptions about the redued growth and yield hanged or if the speies targets varied, the riteria values for the forest plans generated would differ. Forest management deisions under limate hange should be made in aordane with thorough analyses of the riteria values aross different limate hange senarios and assoiated plans. Note that this study addressed only the timber supply and landsape-level speies omposition riteria for evaluating the plan performane. The inorporation of other performane measures suh as additional eologial, eonomi and soial riteria may result in very different deisions. A speial interest for deisions maers and poliy maers is that the proposed framewor is: Iterative as forest plans are generated iteratively over time Interative as staeholders input an be inluded into the model development and into the seletion of robust forest plans Balaning sine the framewor inludes multiple goals allowing for assessment of trade-offs among ompeting interests Deals with unertainty by inluding a range of future limates into deision proess Provides robust forest plans that are good-enough under the worst ase limate senarios There is a lear need for further large-sale, longer-term studies of forest management under unertainty related to limate hange. This study also illustrates a need for eduating the publi and staeholders about deep unertainty and approahes to deal with it. Anowledgements Funding for this projet was provided by the Future Forest Eosystem Sientifi Counil. Administrative support was provided by the Department of Forest Sienes, University of British Columbia in Vanouver. We than Phil Winle for providing a lin to the Quesnel Timber Supply Mitigation Committee, Tongli Wang for generating limate variable/bec zone projetions for the projet study area, Arnold Moy for GIS support and Linda Wong for omputational help. Contat Emina Krmar University of British Columbia Department of Forest Sienes 2424 Main Mall, Vanouver, BC V6T 1Z4 Tel: (604) ermar@mail.ub.a 2

4 Table of Contents Introdution Methodology Forest planning under limate hange in the Quesnel study area Results Disussion and onlusions Literature Appendix List of Tables Table 1. Goals, riteria and objetives of strategi forest managemnt planning under limate hange for the Quesnel study Table 2. Quesnel TSA land base lassifiation Table 3. Tree speies aross Quesnel THLB Table 4. Landsape-level renewal assumptions Table 5. Stand- level renewal assumptions Table 6. Climate hange senarios Table 7. Projeted area (ha) of BEC zone limate envelopes aross Quesnel THLB Table 8. Projeted frequeny of ourrene of three speies in the Quesnel THLB Table 9. Current, projeted and target ourrene frequeny of the three speies in Quesnel THLB Table 10. Average ourrene frequeny (%) of the ey speies for the plans A0-F and limate senarios C Table 11. Minimum period (million m3) for the plans A0-F and limate senarios C Table 12. Maximum deviation (million m3) between period harvests for the plans A0-F and limate senarios C Table 13. Average ourrene frequeny (%) of the ey speies for the plans A1-F and limate senarios C 1 Table 14. Minimum period harvest (million m3) for the plans A1-F and limate senarios C 1 Table 15. Maximum deviation (million m3) between period harvests for the plans A1-F and limate senarios C 1 Table 16. Projeted area (ha) by speies in eah period over the horizon for A1-Plan3 Table 17. Projeted area (ha) by speies in eah period over the horizon for A1-Plan4 3

5 List of Figures Figure 1. Map of the Quesnel TSA Figure 2. Current BEC zones aross Quesnel THLB Figure 3. Projeted limate envelopes for BEC zones aross Quesnel THLB in 2020s for seleted limate hange senarios Figure 4. Projeted limate envelopes for BEC zones aross Quesnel THLB in 2050s for seleted limate hange senarios Figure 5. Projeted limate envelopes for BEC zones aross Quesnel THLB in 2080s for seleted limate hange senarios Figure 6. Minimum period harvest and average speies ourrene frequeny for the A1 plans Figure 7. Maximum flow deviation for the A1 plans Appendix: List of Tables Table A1. Biogeolimati zones in BC Table A2. Average frequeny relative to the target frequeny over the horizon for A0-Plan0 and A0-Plan3 Table A3. Period volume (million m3) over the horizon for A0-Plan0 and A0-Plan3 Table A4. Maximum deviation between the period harvest volumes (million m3) over the horizon for A0- Plan0 and A0-Plan3 Table A5. Average frequeny relative to the target frequeny over the horizon for A1-Plan1 and A1-Plan6 Table A6. Period volume (million m3) over the horizon for A1-Plan1 and A1-Plan6 Table A7. Maximum deviation between the period harvest volumes (million m3) over the horizon for A1- Plan1 and A1-Plan6 4

6 Introdution Managing forests under limate hange is a diffiult tas largely beause of the omplexities and unertainties involved. Unertainty about limate hange is ompounded by the impats that limate hange has on forests and forest eosystems, and on the forest setor and forest-based ommunities. Further, it raises questions whether urrent management objetives are appropriate to future hanges. The basi assumption of this study is that there is unertainty in the timing, loation and magnitude of future limate hange, that impats of limate hange on biophysial forest omponents are unertain, that little is nown about soio-eonomi effets, and, finally, that staeholders attitudes towards and response to limate hange are unertain. Muh has been written about unertainty related to limate hange (Toth 2000, Lemprière et al 2008, Metsaranta et al 2011), but unertainties are rarely expliitly onsidered in real-life limate adaptation planning (Preston et al. 2011). There are many possible limate hange senarios, but no single senario an be reommended as the best, whih is a soure of great unertainty. While some unertainties related to limate hange will derease over time with better information available in the future, other unertainties will remain and beome even deeper, but deisions will nevertheless have to be made. Most traditional deision support tools in forest management are based on the assumption that all parameters are nown with ertainty. This assumption implies that it is possible to generate and ompare the outomes for a range of feasible plans and then selet one plan aording to some evaluation riteria. The rare deision support tools that address unertainty in forest planning and management assume that a probability distribution of unertain parameters is provided and that a plan with the highest expeted utility of the outomes is seleted. In this study, we develop a oneptual framewor for forest management deisions under limate hange using the Quesnel forest distrit as a ase study. For the initial analyses in the ontext of the Quesnel study area, a robust plan is defined as the one that eeps all riteria values within ertain limits under projeted senarios of limate hange. Methodology Multi-Criteria Deision Analysis A forest manager searhes for management plans that balane multiple goals. The suess of a plan in aomplishing different goals is measured using soial, eonomi and environmental indiators. Let a (performane) riterion of plan x be denoted by g ( x), K. The set X of feasible forest management plans is generated under onstraints on land availability, harvest, regeneration, and silviulture ativities, 1

7 the initial and terminal inventories, and the non-negativity onstraints. A planning problem an then be formulated as: Max{ g ( x), K}, subjet to x X (MC) where x is a plan from a set X. The use of maximization does not redue the appliation of the (MC) formulation as minimization is diretly onverted into maximization by Min g( x) = Max[ g( x)], subjet to x X A methodologial approah designed for developing and evaluating alternative plans while aounting for multiple, and often onfliting, goals is referred to as multi-riteria deision analysis (MCDA). More narrowly MCDA an be defined as a tool to help deision-maers identify plans that maximize their satisfation aross several riteria. One way to solve a MCDA problem is to onstrut an aggregate riterion to be optimized. A distane between the urrent riteria values and the target values an be used as the aggregate riterion (Belton and Stewart 2001). In real life problems, multiple riteria are usually in onflit and there are no feasible plans that ahieve simultaneously the highest values for all riteria. Nevertheless, an ideal point that onsists of the best riteria values would be a natural planning target. For any riterion, the upper bound * * g g ( x), x X an be used as the best riterion value g, K, while the lower bound g * g ( x), x X is used as the worst riterion value g *, K. The best riteria values * * g, K are inorporated into an ideal vetor g and the worst riteria values g *, K into a nadir vetor g *. Both ideal and nadir points are used to onstrut the aggregate riterion in terms of the * g g ( x) normalized distane from the desired referene point. Let d ( x) =, K denote the * g g * distane of the urrent riterion value from its best value, normalized by the range of values g g *. The plan x* that minimizes the weighted sum of distanes d (x) is a solution to (MC). In other words, x* is a solution to the program Min S( w, x) = Min w d ( x) where weights w K x X x X K w ( 0,1), K; = 1 reflet the relative importane of the riteria. Dealing with the limate hange unertainty One of the assumptions of the (MC) model is that all parameters are nown with ertainty. When limate hange is expliitly taen into aount, the model an be reformulated as Max{ g ( x), K}, subjet to x X, C (MC_C) * 2

8 Parameter taes the values aross the set of limate hange senarios C. All other parameters and variables are defined as for (MC). Although in theory the set of limate hange senarios C is infinite and the set of assoiated model parameters ontinuous, we assume that taes disrete values from a finite set C. The urrent limate projetions are subjet to large unertainties (Refsgaard et al. 2012). Forest management deisions under limate hange are espeially hard to mae beause of unertainties related to limate projetions as well as unertainties inherent to forest eosystems. These deisions are also influened by a range of staeholders with different interests and different ris pereptions. For many years, unertainty has been reognized by UN Intergovernmental Panel on Climate Change (IPCC) as important (Moss and Shneider 2000; IPCC 2007). The omplex nature of unertainty in the limate-related deision-maing is enapsulated by Shneider (2003): the limate hange debate is haraterized by deep unertainty, whih results from fators suh as la of information, disagreement about what is nown or even nowable, linguisti impreision, statistial variation, measurement error, approximation, subjetive judgment, and disagreement about strutural models, among others. Moreover, limate hange is not just a sientifi topi but also a matter of publi and politial debate, and degrees of unertainty may be played up or down (and further onfused, whatever the ase) by staeholders in that debate. In all management deisions the negative impats of unertainty an be redued with the robust ation plans that try to avoid disasters under the potentially worst ase limate onditions (Dessai and Hulme 2007). The onept of robustness is losely related, but not restrited, to the notions of flexibility, stability and sensitivity (Roy 2010). In this report, we limit the omplex notion of robustness to the onept of satisfiing, a term used to desribe a ross between satisfying and suffiing (Simon 1957). Rather than looing for optimal plans assuming that future onditions are nown, a robust approah searhes for satisfiing or good-enough plans under a range of unnown future onditions. Robust deisions always reflet some degree of pessimism, resulting in redued levels of the objetive (Roy 2010; Groves and Lempert 2007). Robust deision maing is not a speifi tehnique but, rather, an iterative and interative framewor that helps identify and evaluate potential robust plans. The best plans relative to a ertain measure of robustness are alled robust plans (Roy 2010). Commonly used robustness measures are absolute robustness, absolute deviation and relative deviation (Roy 2010). Under the onept of absolute robustness, the robust plan in this report is defined as a plan that maximizes the riteria values for the worst senario. Framewors for forest management planning under limate hange Under limate hange, there is a need for major hanges in the way forest renewal is onduted in British Columbia (Campbell et al 2009). Adaptation to limate hange enompasses management ativities that aim to redue the potential negative impats of limate hange and to apture opportunities arising from 3

9 the potential positive impats of limate hange. Strategi forest planning that onsiders multiple timber and non-timber values should also inlude adaptation to limate hange. Both the physial parameters of limate hange and the response of forest eosystems over the next several deades are highly unertain. As a onsequene, managers are faed with a situation in whih there is no single optimal forest plan. They need a flexible framewor for designing strategi forest plans that tae limate hange into onsideration. Strategi forest management plans ould be designed following the established steps of adaptive management framewor (Taylor et al. 1997). Framewor for (strategi) forest planning under limate hange Generate forest management plans for the urrent planning horizon Step 1: Data olletion Step 2: Define goals, riteria, objetives and targets Step 3: Generate forest management plans that balane multiple goals Step 4: Selet plan(s) that ahieve good-enough outomes for all limate onditions onsidered Step 6: Implement the plan(s) Step 7: Monitor Step 8: Evaluate Next planning horizon Go to Step 1. The plan needs to be evaluated on a short-term basis (i.e. 3-year or 5-year) using speifi assessment riteria based on the initially formulated goals. Further we provide details of Steps 1 to 4: Step D1i: Biophysial, soial and eonomi data; selet limate hange senarios C={ i }, i I Step D1ii: Selet an adaptation option a A Step D2i: Define riteria G={g }, Step D2ii: Set targets Q={q }, K K Step D2iii: Formulate the multiple-riteria model (MC_C) 4

10 Step D3i: Generate forest plans, F ={f }, C by solving (MC_C). Step D3ii: Determine the riteria values g ( f )} for eah g G and eah f F. { Step D4i: Are there forest plans f F 1 F so that g ( f ) q, for all C? Step D4ii: Yes. F 1 F is the set of robust forest plans for target Q. STOP. Step D4iii: No. Are there forest plans g >> ( f ) q? f F 2 F and limate senarios C C so that op Step D4iv: Yes. 2 C op C is the set of limate senarios that provide opportunities for plans f. F Step D4v: No. Are there limate senarios f F? C vl C C so that g < ( f ) q for all forest plans Step D4vi: Yes. C vl C is the set of limate senarios that plans f F are vulnerable to. Set C = C vl. Step D4vii: Have all the adaptation senarios been applied? Step D4viii: Yes. No robust solution for the target set Q. GOTO Step D4x. Step D4ix: No. New adaptation senario a. GOTO Step D2i. Step D4x: Can the targets be relaxed? Step D4xi: Yes. Relax the targets, next Q. GOTO Step D2ii. Step D4xii: No. GOTO Step D4vii. The forgoing framewor allows for gradual adaptation and learning about limate hange and its impats on forest eosystems. Although the strategi forest plan, inluding adaptation to limate hange, is developed for a long planning horizon, implementation addresses only parts of the landsape sheduled for harvesting and renewal in the first few years of the horizon. Implementation of the plan is to be monitored and evaluated after 5 years (or earlier). At this stage, the whole proess is repeated using the newly aquired nowledge about limate hange and the effets that arise when the plan has been implemented. 5

11 Forest planning under limate hange in the Quesnel study area The Quesnel Timber Supply Area (TSA), loated in the entral interior of British Columbia, overs approximately 2 million ha (Figure 1, BC MFR 2007a). The forest industry is the most important setor in the area, with two pulp mills, five large sawmills, a plywood plant, a medium-density fibreboard plant and several smaller, value-added manufaturing operations. Figure 1. Map of the Quesnel TSA The Quesnel ommunity has reently experiened a boom in wood proessing, mainly due to a large amount of mountain pine beetle infested wood that had to be proessed. Forest planning over the long term needs to address timber supply onerns as well as those for the forest eosystems and aim to redue the potential negative impats of limate hange. One way to redue these impats is by failitating the shifting of speies distributions and omposition. Under limate hange, speies distribution and omposition will hange mainly by natural regeneration after harvesting and natural disturbanes. To overome the lower natural establishment rate of ertain speies, planting rules an be hanged to allow for modifiations of the existing speies distribution and omposition. The suess of forest management plans in aomplishing different goals an be measured using soial, eonomi and eologial riteria. For the Quesnel study area, the overall objetive of strategi forest planning is to provide a balane between several ompeteing interests under unertainties related to 6

12 limate hange. The timber supply goal addresses the adequate supply of fiber for mills and satisfying ontratual obligations with the Provine and industry. The eologial goal addresses the landsape-level speies omposition (Mah et al 2012). The goals, riteria and objetives of strategi forest management planning under limate hange for the Quesnel study are presented in Table 1. Table 1. Goals, riteria and objetives of strategi forest managemnt planning under limate hange for the Quesnel study Goal Criterion Objetive Ahieve high period harvest over time (average) PrVol (m3) Max PrVol Maintain stable harvest flow (average) FlowDev (m3) Min FlowDev Meet speies ourrene frequeny target (average) SpFreq (%) Max SpFreq To formulate a strategi planning model, forest over attributes (e.g., speies, site index, age) are aggregated into strata m M. If some forest harateristis are to be emphasized in the model, M an be partitioned aordingly. Denote by M s a set of management strata for seleted speies s S. Let p be a management treatment from the set of treatments P mt appropriate to stratum m in period t, where t T is a deadal period in a planning horizon. Management treatments inlude various ombinations of harvest and reforestation ativities. A deision variable x = xmpt represents the area of forestland in stratum m managed by treatment p in period t. The timber-supply goal is aomplished through the even flow of harvest volume over time oupled with maximization of the period volume beause this drives fiber supply as high as possible. Let v mpt (m 3 /ha) be the merhantable volume from a hetare of stratum m managed by treatment p in period t under assumed limate senario. Denote by Vol t, (x) the harvest volume (m 3 ) in period t and by FlowD (x) the average deviation from the stable flow, both under assumed limate senario. Period harvest: Vol t, ( x) = m M p P mt v mpt x mpt Average harvest flow deviation: FlowD x) avg Vol ( x) Vol ( ) ( = t+ 1, t, x t The eologial goal addresses the landsape-level omposition of ertain speies from set S. The related riterion is formulated as the average deviation of the modeled ourrene frequeny F t s (x) for plan x from the target ourrene frequeny TF of speies s S in period t under limate senario. Both the t s 7

13 modeled ourrene frequeny and the target frequeny of ourrene of speies are expressed as portions (%) of the study area. Average deviation from target frequeny of ourene: TreeD ( x) = avg F ( x) TF When the target frequenyof ourene of speies is fully ahieved, TreeD (x) is zero. In all other ases, TreeD (x) reflets the average deviation from the target frequeny. If the eologial goal is to ahieve the target ourrene frequeny, the riterion TreeD (x) is to be minimized. The multi-riteria model (MC_C) is formulated as t, s t s t s (FREQ) (VOL) (EVEN) subjet to Min TreeD (x) Max Vol t, (x) Min FlowD (x) x X, C. The set X onsists of the tehnial onstraints on land availability, harvest, renewal, and silviulture ativities, the initial and terminal timber inventories, and the non-negativity onstraints. Here is a limate related parameter and C is a set of limate hange senarios. Model implementation Approximately 1 million hetares of the Quesnel TSA are lassified as the timber harvesting land base (THLB). The THLB is divided into strata aording to biogeolimati (BEC) zones, tree speies, site index and age lasses. The forest resoures inlude five dominant speies: interior Douglas-fir, sprue (exept bla sprue), lodgepole pine, some western edar, and deiduous speies (mainly aspen) growing on poor, medium and good produtivity lasses. Land base lassifiation details are presented in Tables 2 and 3. Table 2. Quesnel TSA land base lassifiation Land base lassifiation Area (ha) Perentage of total land base area Total land base area 2,077, % Non-ontributing forest landbase 330, % Timber harvesting landbase (THLB) 992, % 8

14 Table 3. Tree speies aross Quesnel THLB a Speies THLB area (ha) Perentage of THLB Fir 49, % Sprue 139, % Pine 758, % Cedar % Deiduous 43, % Total 992, % a Soure: Cortex et al. (2006) To redue the potential negative impats of limate hange different forest renewal options may be applied to failitate a shift of speies distribution and a hange of speies omposition. For the ase study, two renewal options are analyzed. The status quo option A0 is the one urrently employed for the Quesnel THLB, with regeneration of harvested stands that preserves pre-harvest speies frequeny of ourrene. Another renewal option addresses forest resiliene to hanging limate by promoting hanges to the speies omposition (BC MoFR 2008). For eah of the renewal options, we designed models that determine the area and the period of appliation of harvest/regeneration treatments to meet the objetives over a 100-year planning horizon divided into deades. Management assumptions used in developing models for the Quesnel TSA are based on two douments: a onsulting report developed for the Quesnel TSA (Buell et al. 2006) and silviulture reommendations obtained from Phil Winle (June, Sept 2010). The two silviulture treatments onsidered are natural regeneration and planting. The treatments differ in the landsape level speies omposition under different renewal options (Table 4). Table 4. Landsape-level renewal assumptions Renewal option Treatment Desription A0 A1 Natural all deiduous stands and poor oniferous stands after harvest/natural disturbane pre-harvest speies frequeny of ourrene over the landsape is maintained pre-harvest speies frequeny of ourrene over the landsape is maintained Planting all medium and good oniferous stands after harvest/natural disturbane pre-harvest speies frequeny of ourrene over the landsape is maintained pre-harvest frequeny of ourrene of speies may hange to meet the target frequeny of ourrene of speies and timber supply goals 9

15 In addition to the renewal of fir and sprue stands by preserving the pre-harvest omposition, we added the possibility to plant speies that are adaptable to limate hange. Table 5. Stand- level renewal assumptions a Speies/Site Regeneration delay (years) Regeneration method Fir (good, medium) 2 Plant Sprue (good, medium) 2 Plant Pine (good, medium) 2 Plant Cedar (good, medium) 2 Plant Fir, Sprue, Pine (poor) 2 Natural Deiduous (all) 2 Natural a Soure: Buell et al (2006) The limate hange senarios set C onsists of the eleven senarios presented in Table 6. The no hange senario is used to reate referene levels for the outomes, while the remaining ten senarios are those reommended for appliation in BC (Spittlehouse and Murdo 2010). The no hange limate senario is based on the assumption that the average limati onditions observed for will prevail in the future. Table 6. Climate hange senarios Model Emissions Run Desription 0 No hange 1 CGCM3 A2 4 Warm and wet 2 HadCM3 B1 1 Cool and moist 3 HadGEM A1B 1 Hot and dry 4 GFDLCM21 A2 1 5 CSIROMK30 B1 1 6 NCARCCSM30 A1B 5 7 GISS-EH A1B 3 8 CGCM3 A2 5 9 ECHAM5 B MRICGCM232A B1 5 The projeted BEC limate envelopes aross Quesnel THLB for the limate hange senarios are presented in Table 7. All projetions are made for the seleted eleven limate hange senarios and three projetion periods 2020, 2050 and

16 Table 7. Projeted area (ha) of BEC zone limate envelopes aross Quesnel THLB Projetion period BG BWBS CWH ESSF ICH IDF IMA MH MS PP SBPS SBS /50/ Figure 2 illustrates the urrent distribution of BEC zones aross the Quesnel THLB; Figures 3, 4 and 5 illustrate projeted distributions of BEC zone limate envelopes for the seleted limate hange senarios and the respetive projetion periods 2020s, 2050s and 2080s. All projetions presented in Table 7 and illustrated by Figures 3, 4 and 5 were generated by Climate BC/WNA (Wang 2011). 11

17 Figure 2. Current BEC zones aross Quesnel THLB No hange Warm & wet Cool & moist Hot & dry Figure 3. Projeted limate envelopes for BEC zones aross Quesnel THLB in 2020s for seleted limate hange senarios 12

18 No hange Warm & wet Cool & moist Hot & dry Figure 4. Projeted limate envelopes for BEC zones aross Quesnel THLB in 2050s for seleted limate hange senarios No hange Wet & Warm Cool & Moist Hot & Dry Figure 5. Projeted limate envelopes for BEC zones aross Quesnel THLB in 2080s for seleted limate hange senarios 13

19 Speies omposition The renewal option A1 an be onsidered adaptation of forest management to the hanging limate. One of the first steps in integrating this adaptation option into a planning proess is to define the landsapelevel speies omposition targets (Mah et al 2012). In the absene of an established methodology, we define the targets in terms of the projeted frequeny of ourrene of tree speies at the landsape-level under seleted limate hange senarios. We projeted the frequenies of ourrene of the three speies (lodgepole pine, sprue and interior Douglas fir) in the Quesnel study area for the referene period , and the 2020s, 2050s and 2080s similar to Hamann and Wang (2006) and Wang et al. (2012). The ourrene frequeny of major speies in British Columbia has been estimated for eah BEC zone (Hamann et al. 2005). By assoiating the ourrene frequeny of the ey speies for the Quesnel study area with the projeted limate envelopes for the eleven limate hange senarios (Table 6), we projeted the future ourrene frequeny of these speies assuming no barriers to speies migration (Table 8). Table 8. Projeted frequeny of ourrene of three speies in the Quesnel THLB Projetion period Sprue Pine Fir C#0 2020/2050/ % 44.7% 9.1% C# % 27.2% 15.6% % 18.2% 23.4% % 10.6% 30.4% C# % 38.1% 8.8% % 27.2% 8.9% % 23.2% 10.5% C# % 32.3% 11.6% % 12.4% 44.4% % 10.2% 39.1% C# % 7.1% 29.8% % 6.6% 20.3% % 4.3% 1.8% C# % 7.8% 46.3% % 7.5% 38.4% % 6.9% 33.8% C# % 6.2% 27.2% % 4.7% 11.8% % 4.9% 11.9% C# % 7.4% 38.2% % 6.7% 31.0% % 4.6% 11.3% C# % 6.7% 29.8% 14

20 % 5.5% 11.4% % 4.5% 4.1% C# % 7.8% 43.0% % 6.9% 32.2% % 6.9% 32.2% C# % 7.8% 32.6% % 7.7% 39.3% % 6.7% 28.9% Note that the projeted ourrene frequenies of sprue, pine and fir under no hange limate senario (=0) differ signifiantly from the urrent speies frequeny in the area (Table 3). The urrent ourrene frequeny 76.5% of pine-leading stands is signifiantly higher than the projeted ourrene frequeny of pine in the study area. Note that the landsape omposition dominated by older pine stands has been onsidered as one the auses of the reent MPB epidemi (Safranyi and Carroll 2006). Maintaining similar tree speies omposition in the future may ause further eologial, eonomi and soial hallenges in the area. We set up the target ourrene frequeny equal to the projeted frequeny of ourrene of tree speies under speifi limate senario. As an example, the urrent, projeted and target ourrene frequenies for three speies under no hange (=0) limate senario are presented in Table 9. Table 9. Current, projeted and target ourrene frequeny of the three speies in Quesnel THLB Speies Sprue Pine Fir Current frequeny of ourrene 5.0% 76.5% 14.09% Projeted ourrene frequeny ( under =0) 5.0% 44.7% 9.10% Target ourrene frequeny ( under =0) 5.0% 44.7% 9.10% Forest growth and yield Growth and yield of the tree speies suitable for the projeted BEC zone limate envelopes was estimated using TIPSY v.4.1d (BC MFR 2007b). The reent results for lodgepole pine show a redution in yield of approximately 10% on the sites maladapted to the projeted limate (O Neill and Nigh 2011). We deided to ouple these results with some estimates of tree deay and mortality, inset infestation and wild fires due to potentially severe drought and other extreme events. To inorporate the negative impats of limate hange on tree speies distributed outside the projeted BEC zones, the stand yield estimates are redued by 30%. 15

21 The management problem for Quesnel was formulated as a series of multi-riteria linear models (Krmar et al. 2009; Krmar and van Kooten 2008). The model was oded in GAMS (Brooe et al. 2004) and solved using the CPLEX solver on the GAMS platform. Results A MCDA model developed by Krmar et al. (2005) was modified and adjusted to inlude impats of limate hange. For eah of the two adaptation options, a series of linear models was developed and oded in GAMS. For eah adaptation option, several forest management plans were generated assuming that future limate will follow patterns projeted by different limate hange senarios. Several outomes were alulated for eah management plan to evaluate the timber supply and eologial impats. Timber supply impats were assessed by the period harvest volume and flutuations of harvest volumes between periods. Eologial impats were assessed in terms of the tree speies ourrene frequeny relative to the target tree speies ourrene frequeny. Results under renewal option A0 Model (MC_C) designed for the Quesnel study area was solved for eah senario from set C={ i, i=0,1,..,10} thereby produing eleven individual forest plans A0-F={A0-plan i, i=0,1,..,10}. Assuming that different limates may our in the future, average ourrene frequeny of the ey speies relative to the target ourrene frequeny, minimum period harvest volume and maximum flow deviation were determined for eah individual plan. Tables 10, 11 and 12 inlude the riteria values for the eleven forest plans and limate hange senarios from set C under renewal option A0. Constrution of the tables is desribed in detail in the Appendix using A0-Plan0 and A0-Plan3 as examples. We desribe in detail the implementation of the framewor for forest management planning under limate hange to the Quesnel study area. Assume that deision-maers set up the desired values for the three riteria -- average ourrene frequeny of speies, minimum period harvest volume and maximum flow deviation between periods -- at 70%, 26 million m 3 and 1 million m 3. For limate senario =3, the average ourrene frequeny of speies is below a desired value of 70%. This an be interpreted as the vulnerability of the A0-F plans in terms of the ourrene frequeny of 1 2 speies for the limate senarios from C vl ={ 3}. For limate senarios from C vl ={1, 3, 4, 8}, minimum period harvest is below a desired value of 26 million m 3. On the other hand, maximum deviation between period harvests exeeds 1 million m 3 3 for limate senarios from C vl ={1, 3, 4, 6, 8}. This means that the A0-F plans are vulnerable in terms of the harvest flow to limate senarios fromc 3 vl. The set of vulnerability of the A0-F plans with regard to all riteria is defined as the union of the individual vulnerability sets, C = C = {1, 3, 4, 6, 8}. vl vl 16

22 Upon the framewor implementation, no robust forest plans are found among A0-F plans for all limate senarios from C. However, the initial set C of eleven limate senarios was redued to a subset C vl of five limate senarios to whih forest plans were partiularly vulnerable aross all riteria. None of the A0-F plans an be onsidered a robust plan for limate senarios from both sets C and C vl beause the riteria values are far from the desired values espeially under limate senarios =1 or =3. Table 10. Average ourrene frequeny (%) of the ey speies for the plans A0-F and limate senarios C A0-Plans /Plan Min Table 11. Minimum period (million m3) for the plans A0-F and limate senarios C A0-Plans /Plan Min

23 Table 12. Maximum deviation (million m3) between period harvests for the plans A0-F and limate senarios C A0-Plans /Plan Max The Quesnel forest planning problem is further analyzed for the redued set C vl while introduing a new renewal-adaptation option A1. Results under adaptation option A1 To inrease the period harvests, redue flutuations of harvest flow over time and meet the targets for speies ourrene frequeny, we generated a set A1-F={ A1-Plani, i=1,3,4,6,8} of forest plans under the renewal-adaptation option A1 assuming that limate may follow patterns projeted by one of the senarios from C 1 = C vl = {i, i=1,3,4,6,8}. Tables 13, 14 and 15 inlude values of three riteria average ourrene frequeny of the ey speies, minimum period harvest volume and maximum harvest flow deviation alulated for the five forest plans from A1-F and limate hange senarios from C 1. Constrution of the tables is desribed in details in the Appendix using A1-Plan1 and A1-Plan6 as examples. Table 13. Average ourrene frequeny (%) of the ey speies for the plans A1-F and limate senarios C 1 A1 Plan1 A1 Plan3 A1 Plan4 A1 Plan6 A1 Plan8 1 81% 83% 80% 83% 73% 3 78% 85% 77% 85% 69% 4 80% 85% 80% 85% 73% 6 83% 84% 82% 84% 75% 8 81% 82% 81% 81% 74% min aross 78% 82% 77% 81% 69% max min= 82% 18

24 Table 14. Minimum period harvest (million m3) for the plans A1-F and limate senarios C 1 A1-Plan1 A1-Plan3 A1-Plan4 A1-Plan6 A1-Plan min aross max min= Table 15. Maximum deviation (million m3) between period harvests for the plans A1-F and limate senarios C 1 A1-Plan1 A1-Plan3 A1-Plan4 A1-Plan6 A1-Plan max aross min max= After examining the riteria values in Tables 13, 14 and 15, two plans are seleted as the potential robust plans. The plans A1-Plan3 and A1-Plan4 both ahieve superior values for the period harvest volumes and average frequeny of ourrene of the ey speies ompared to other plans from A1-F, but are somewhat inferior to other plans from A1-F in terms of the maximum harvest flow deviation (Figures 6 and 7). Both plans have the average frequeny of ourrene of the ey speies relative to the target frequeny over 77%, minimum period harvest volume above 30 million m 3 and maximum flow deviation between periods does not exeed 0.5 million m 3. Note that all three riteria values ahieved for A1-Plan3 and A1- Plan4 are improved relative to the desired riteria values under the renewal option A0 (no adaptation). 19

25 A1-Plan1 A1-Plan3 A1-Plan4 A1-Plan6 A1-Plan8 0.9 Avg Spe Freq (%) Min period volume (mil m3) Figure 6. Minimum period harvest and average speies ourrene frequeny for the A1 plans A1-Plan1 A1-Plan3 A1-Plan4 A1-Plan6 A1-Plan8 0.6 Max Flow dev (mil m3) Climate hange senario Figure 7. Maximum flow deviation for the A1 plans The potential robust plans are also examined from the perspetive of the projeted ourrene of speies over time (Tables 16 and 17). A1-Plan3 was generated as a solution of the (MC_C) program assuming that future limate will follow the limate pattern projeted by the senario =3 (HadGEM-A1B). The plan involves intensive harvest of pine followed by reforestation using a ombination of fir and pine. Fir planting dominates planting of pine over the whole horizon and this dominane is partiularly signifiant 20

26 in the first half of the horizon. In the first period, all harvested pine stands are reforested by fir. In period 2, harvested pine stands are reforested with fir and a small portion with pine. Starting in period 4, reforestation with pine inreases and reahes approximately one third of the area of fir plantations. The original pine stands inlude fir and pine in the ratio of 5:2 by the end of the planning horizon (Table 16). Table 16. Projeted area (ha) by speies in eah period over the horizon for A1-Plan3 Period Speies F a 49,469 49,469 49,469 49,469 49,469 49,469 49,469 49,469 49,469 S b 139, , , , , , , , ,821 P 758, , , , , , ,379 92,508 10,441 C d D e 43,769 43,769 43,769 43,769 43,769 43,769 43,769 43,769 43,769 FPL f 148, , , , , , , ,191 SPL g 7,234 PPL h 51,288 51, , , , , ,875 a fir; b sprue; pine; d edar; e deiduous; f original pine stands planted by fir; g original pine stands planted by sprue; h original pine stands planted by pine A1-Plan4 was determined as a solution of the (MC_C) program assuming that future limate will follow the limate pattern projeted by the senario =4 (GFDLCM21-A2). A1-Plan4 involves intensive harvest of pine followed by planting using a ombination of fir, sprue and pine. In the first period, harvested pine stands are planted with approximately equal portions of fir and sprue. After the pine harvest in period 2 the stands are planted with approximately equal portions of pine, fir and sprue. In period 3, the area planted with fir and sprue almost doubles relative to the fir and sprue planting in the previous period. From period 4, the area replanted with pine inreases steadily. By the end of planning horizon, the original pine stands are overed with approximately equal portions of pine, fir and sprue (Table 17). Table 17. Projeted area (ha) by speies in eah period over the horizon for A1-Plan4 Period Speies F a 49,469 49,469 49,469 49,469 49,469 49,469 49,469 49,469 49,469 S b 139, , , , , , , , ,821 P 758, , , , , , ,186 63,364 10,441 C d D e 43,769 43,769 43,769 43,769 43,769 43,769 43,769 43,769 43,769 FPL f 74,964 74, , , , , , ,419 SPL g 88,624 88, , , , , , ,806 PPL h 90,938 98, , , , , ,074 a fir; b sprue; pine; d edar; e deiduous; f original pine stands planted by fir; g original pine stands planted by sprue; h original pine stands planted by pine 21

27 The A1-Plan4 seems lie a suitable one for implementation beause of the fewer hanges of the urrent renewal patterns ompared to A1-Plan3. Seleting the forest management plan for implementation will depend on other fators that are beyond the sope of this projet. Staeholders may request repeating the deision proess with additional and/or different eologial, eonomi and soial goals and riteria. Disussion and onlusions We developed a framewor for supporting forest management planning under limate hange. The framewor addresses unertainty of the limate hange projetions and its impat on forest management deisions. Unertainty related to limate projetions affets a number of variables and parameters involved in forest planning. Our study expliitly addresses unertainty regarding the speies omposition and forest produtivity, both related to the limate projetion unertainty. Note that other unertainties inherent to forest planning are beyond the sope of the study. All results of the ase study are valid only under the given assumptions and represent relative rather than absolute values. No potential positive impats of future limate on forest produtivity (Nigh et al. 2004) are taen into aount. If these impats were onsidered or if the assumptions about the redued growth and yield hanged, the projeted riteria values would liely differ signifiantly. Forest management deisions under limate hange should be done in aordane with thorough analyses of the riteria values aross different limate hange senarios and assoiated plans. Note that, in this study, we used only the timber supply and landsape-level speies omposition as the performane measures for the plan evaluation. The inorporation of other performane measures, suh as additional eologial, eonomi and soial riteria, may lead to different deisions. A speial interest for deisions maers and poliy maers is that the proposed framewor is: Iterative as forest plans are generated iteratively over time Interative as staeholders input an be inluded into the model development and into the seletion of robust forest plans Balaning sine the framewor inludes multiple goals allowing for assessment of trade-offs among ompeting interests Deals with unertainty by inluding a range of future limates into deision proess Provides robust forest plans that are good-enough under the worst ase limate senarios 22