Economics of boreal Scots pine management under changing climate

Transcription

1 Economics of boreal Scots pine management under changing climate Sampo Pihlainen 1 * Olli Tahvonen 1 Annikki Mäkelä 1 1 Department of Forest Sciences, University of Helsinki, Latokartanonkaari 7, PL 27, *sampo.pihlainen@helsinki.fi Economic-ecological optimization group (Olli Tahvonen)

2 Research consortium funded by the Academy of Finland as a part of Finnish Climate Change Research Programme (FICCA) Economically Optimal Adaptation of Forest Management in the Changing Climate (EconAda) Raisa Mäkipää (coordinator), Tapio Linkosalo, et al., Finnish Forest Research Institute (Metla) Olli Tahvonen (principal investigator), Sampo Pihlainen et al., University of Helsinki

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4 Articles in my thesis Economics of boreal Scots pine management under changing climate (Manuscript)

5 Introduction Climate change poses an immense challenge to the mankind. Forests have an outstanding role in its mitigation (IPCC 2007) Current decisions anticipate future growth conditions for a long time horizon Scots pine (Pinus sylvestris L.) is one of the most abundant tree species in the world Its significance increases with climate change because of its heat tolerance (Lutz et al. 2013)

6 Literature review: timber Forest growth increases in Fennoscandia limiting factors: short growing season and low temperature and nitrogen Kellomäki et al Climatic Change Timber yields increase in Fennoscandia Kellomäki et al For. Ecol. Manage. Pussinen et al For. Ecol. Manage. Garcia-Gonzalo et al Climatic Change Garcia-Gonzalo et al Ecol. Modell. Kellomäki et al Phil. Trans. R. Soc. Alam et al Scand. J. For. Res. Increase in yields is higher in northern areas Beuker et al Silva Fennica Kellomäki and Väisänen 1997 Clim. Change Briceño-Elizondo et al For. Ecol. Manage. Briceño-Elizondo et al Environmental Science and Policy Matala et al Ecol. Modell. Decreasing yields are also found Talkkari and Hypén 1996 For. Ecol. Manage. Talkkari 1996 Silva Fennica Talkkari 1998 For. Ecol. Manage.

7 Literature review: carbon Carbon stock in vegetation increases in Fennoscandia Karjalainen 1996 For. Ecol. Manage. Mäkipää et al Can. J. For. Res. Pussinen et al For. Ecol. Manage. Garcia-Gonzalo et al Clim. Change Garcia-Gonzalo et al Ecol. Modell. Alam et al Scand. J. For. Res. Matala et al European Journal of Forest Research Mäkipää et al J. For. Plann. Overall forest carbon stock may decrease because of the decrease in the soil carbon stock Mäkipää et al Can. J. For. Res. Pussinen et al For. Ecol. Manage. Karjalainen 1996 Biomass and Bioenergy Increasing forest carbon stock is also found Briceño-Elizondo et al Environmental Science and Policy

8 Literature review: adaptation The impact of climate change on timber production and carbon storage is usually studied assuming no adaptation in forest management. Adaptive strategies can be divided in three categories: resistance resilience Millar et al. (2007 Ecological Applications) response adaptation on the extensive margin Guo and Costello (2013 JEEM) adaptation on the intensive margin We study optimization of harvest schedules, thinning prescriptions and initial stand density Before the adaptation in the sense of selecting the most suitable species can be made one must first know the full economic potential of each tree species in changing climate. cf. Guo and Costello (2013 JEEM) and Hanewinkel et al. (2012 Nature Clim. Change)

9 Literature review: adaptation of management Management scenario comparisons in changing climate: Kellomäki and Kolström 1993 For. Ecol. Manage. Kellomäki et al For. Ecol. Manage. Nuutinen et al Clim. Change Briceño-Elizondo et al For. Ecol. Manage. Briceño-Elizondo et al Environmental Science and Policy Garcia-Gonzalo et al Climatic Change Garcia-Gonzalo et al Ecol. Modell. Garcia-Gonzalo et al For. Ecol. Manage. Garcia-Gonzalo et al Forst Jagdzeitung Alam et al Scand. J. For. Res. Optimization of forest management in changing conditions: Pukkala and Kellomäki 2012 Forestry (optimization with two thinnings in changing climate, all rotations equal) Goetz et al Ecol. Econ. (uneven-aged in changing climate) McConnell et al Land Econ. (evolving timber prices and costs in current climate) Löfgren 1985 For. Ecol. Manage. (biotechnological improvements in current climate)

10 Gaps in the literature: 1. No dynamic optimization in changing climate* except Pukkala and Kellomäki 2012 Forestry (all rotations equal) Goetz et al Ecol. Econ. (uneven-aged) 2. No optimization of thinnings* except Pukkala and Kellomäki 2012 Forestry (fixed number of thinnings) 3. No carbon storage objective* 4. Value of adaptation controversial* cf. Guo and Costello 2013 JEEM *Gap exists for any tree species This is the first study of economic optimization of even-aged forest management under changing climate to allow successive rotations to change with climate change to include carbon storage objective

11 Model: growth model Individual-tree process-based growth model Mäkelä 2002 Tree Physiol. Mäkelä and Mäkinen 2003 For. Ecol. Manage. Climate change in the model (Bergström et al. 2011) 4.5 C increase in temperature in the next hundred years 100% increase in CO 2 emissions by the year 2050 and a slight decrease after that enhanced nutrient turnover in the soil organic matter effects of drought Growth model includes a direct link between tree growth and climate change coefficients for photosynthesis, respiration of trees and the biomass allocation to roots Value of coefficient 1,3 1,2 1,1 1,0 0,9 0,8 0, Time, yrs coefficient for photosynthesis coefficient for respiration coefficient for biomass allocation to roots Temperature increase, oc Time, yrs

12 Model: optimization problem The size-age-structured rotation model in changing climate: ( r) k1 k1 k2 k1 k2 k3 max V = ç W1+ b W2 + b W b J, 0, a, s, ü a a ìn k t ïg, d= 1,2,3, ï í dts a ý ïsa= 1,..., ka, ï ïîa= 1,2,3 ïþ æ è t t + t Aö r ø ( h,d ) t + t + t å ka n g tka t é ù sa t a ê åå v ivts it a s t a s t a s ú å c t a s = 1 i= 1 v= 1 t= 0 where W = b p D h - C + b p Q - w, a = 1, 2,3, a ë û % subject to the process-based growth model* ( difference equations). Optimized variables for each rotation: initial density; rotation period; number, timing, type and intensity of thinnings *Mäkelä (2002) and Mäkelä and Mäkinen (2003)

13 Model: CO 2 subsidy system Monetary value via subsidy-based instrument n 2 ì Q = måí( q z 1 - q, -1z 1, -1) + å é ë1-bf ( r) ûx h î { ù } f t it i t i t i t i t it i= 1 f= 1 ü ý þ Net subsidy system Carbon in timber products decays at some rate, Similar to the scheme currently enforced in New Zealand 0< b 1

14 Results: without thinnings Fertile site Infertile site Climate specification Current Changing 1 st rotation 2 nd rotation 3 rd rotation Changed MT VT MT VT CT When no thinnings are allowed, optimal rotations shorten with changing climate. Interest rate 3% MT1300 = Fertile site in Southern Finland VT1300 = Average fertility site in Southern Finland MT1100 = Fertile site in Central Finland VT1100 = Average fertility site in Central Finland CT1300 = Infertile site in Southern Finland

15 Results: with thinnings (a) (b) (c) Volume, m 3 ha Volume, m 3 ha Volume, m 3 ha Stand age, y Stand age, y Stand age, y Current climate and no climate change First rotation in changing climate Second rotation in changing climate Changed climate Average fertility site in Southern Finland, interest rate 3%. Carbon price per ton of CO 2 is (a) 0, (b) 20, (c) 100. (a) With optimal thinnings and without carbon subsidies optimal rotation first lengthens with changing climate, then shortens optimal rotation in changed climate is longer than in current climate optimal number of thinnings increases (b-c) With optimal thinnings and with carbon subsidies optimal rotation shortens with changing climate stocking increases with changing climate intensity of thinnings increases with changing climate thinnings are performed earlier in changing climate cf. Tahvonen et al Can. J. For. Res.

16 Results: value of adaptation MT1300 VT1300 MT1100 VT1100 CT1300 p OPT, CUR, Gain, OPT, CUR, Gain, OPT, CUR, Gain, OPT, CUR, Gain, OPT, CUR, Gain, c % % % % % Note: pc denotes CO 2 price. Adaptation yields notably higher bare land values. Using current climate solutions in changing climate leads to too heavy harvests. Interest rate 3% MT1300 = Fertile site in Southern Finland VT1300 = Average fertility site in Southern Finland MT1100 = Fertile site in Central Finland VT1100 = Average fertility site in Central Finland CT1300 = Infertile site in Southern Finland

17 Results and discussion: carbon and timber Our result: average carbon stock without carbon subsidies % higher in changing climate 38-80% higher in changed climate Comparisons decrease in Karjalainen 1996 Biomass and Bioenergy 10 % increase in Mäkipää et al Can. J. For. Res. increase in Garcia-Gonzalo et al Clim. Change decrease in Mäkipää et al J. For. Plann. Our result : timber yield without carbon subsidies % higher in changing climate % higher in changed climate Comparisons 30% increase in Kellomäki et al For. Ecol. Manage. 40% increase (in North) in Beuker et al Silva Fennica 26-50% increase in Briceño-Elizondo et al For. Ecol. Manage.

18 Thank you! Further information: