ARTICLE Modeling the effects of varied forest management regimes on carbon dynamics in jack pine stands under climate change Weifeng Wang, Changhui Peng, Daniel D. Kneeshaw, Guy R. Larocque, Xiangdong Lei, Qiuan Zhu, Xinzhang Song, and Queju Tong Abstract: Climate change and its potential effects on ecosystems justify the need to implement forest management strategies that increase carbon (C) sequestration. A process-based model, TRIPLEX-Management, was used to investigate how to increase C sequestration within managed jack pine (Pinus banksiana Lamb.) forests. The simulations included a constant climate scenario and two climate change scenarios generated from the Coupled Global Climate Model (CGCM 3.1). A total of 36 forest management scenarios (a control where no forest management occurred, five varied rotation length harvesting-only regimes, and combina- tions of six thinning regimes and five rotation lengths) were simulated under each climate scenario for nine sites characterized by stocking levels from 0.3 to 0.7. A significant increase in C sequestration was generated under the climate change scenarios compared with those under constant climate. Mean annual net ecosystem productivity (NEP) varied with rotation length, but was not changed by precommercial thinning. Future studies should consider life cycle analysis of harvested wood products as in this study they were assumed to be a permanent C sink. Climate warming might enhance limited positive effects of forest thinning on C sequestration. Shortening rotation length from 70–80 years to 50 years might enhance NEP, increase wood production, and decrease the risk of climate change impacts on jack pine forests. Résumé : Les changements climatiques et ses effets potentiels sur les écosystèmes justifient le besoin d'implanter des stratégies d'aménagement qui augmentent la séquestration de carbone (C). Le modèle basé sur les processus TRIPLEX-Management a été utilisé pour déterminer comment augmenter la séquestration de C dans des forêts aménagées de pin gris (Pinus banksiana Lamb.). Les simulations ont inclus un scénario de climat constant et 2 scénarios de changement climatique générés a ` partir du modèle « Coupled Global Climate Model » (CGCM 3.1). Un total de 36 scénarios d'aménagement forestier (témoin sans aucun aménage- ment forestier, cinq régimes de longueurs différentes de rotation avant récolte, et des combinaisons de six régimes d'éclaircie et de cinq longueurs de rotation) ont été simulés sous chacun des scénarios de climat pour neuf sites caractérisés par des niveaux de densités relatives de 0.3 a ` 0.7. Une augmentation significative dans la séquestration de C a été obtenue sous les scénarios de changement climatique comparés aux scénarios témoins avec limat constant. La productivité moyenne nette de l'écosystème a varié avec la longueur de rotation, mais n'a pas été affecté par l'éclaircie précommerciale. L'analyse du cycle de vie des produits de la récolte n'a pas été considérée dans cette étude, car il a été assumé qu'ils constituaient des réservoirs permanents de C. Le réchauffement climatique peut engendrer des effets positifs limités de l'éclaircie sur la séquestration de C. Une diminution de la longueur de rotation de 70–80 années a ` 50 années peut accentuer la productivité nette de l'écosystème, augmenter la production de bois et diminuer le risque des impacts des changements climatiques sur les forêts de pin gris. Introduction The influence of forest management practices on forest carbon (C) cycling is now widely accepted (Brown et al. 1996; Liu et al. 2011). Within the context of global climate change, this recogni- tion has sparked the development and evolution of forest man- agement strategies as a means of mitigating global climate change (Malmsheimer et al. 2008; D'Amato et al. 2011; Law and Harmon 2011). Two general approaches have been proposed to mitigate climate change relative to existing forests: (1) increase C stocks on-site or in harvested wood products (e.g., Seidl et al. 2007; Chen et al. 2008) and (2) substitute fossil fuels with bioen- ergy (e.g., Malmsheimer et al. 2008; Hudiburg et al. 2011). None- theless, traditional silvicultural research has focused primarily on timber production, thus leaving a knowledge gap in current ef- forts to develop sustainable forest management strategies that will increase C stocks on-site as well as in harvested wood C under conditions of a changing climate. Forest management is an anthropogenic disturbance that has great potential to affect the C cycle (Liu et al. 2011). For example, forest thinning can be used early in stand development to en- hance individual-tree diameter and volume growth, but not nec- essarily increase the overall C stock. It is thus equivocal as to whether thinning increases the overall C stock as increased growth is offset by tree removal (e.g., Tong et al. 2005; Lei et al. 2007). Stand-replacing harvests would also lead to C losses directly or indirectly through the conversion of C stored in living trees to C stored in harvested wood, as well as through the decomposition of logging debris, litterfall, and soil organic C (Amiro et al. 2010; Received 2 August 2012. Accepted 4 March 2013. W. Wang.* Institut des Sciences de l'Environnement, Université du Québec a ` Montréal, Case Postale 8888, Succ. Centre-Ville, Montreal, QC H3C 3P8, Canada. C. Peng. Institut des Sciences de l'Environnement, Université du Québec a ` Montréal, Case Postale 8888, Succ. Centre-Ville, Montreal, QC H3C 3P8, Canada; Laboratory for Ecological Forecasting and Global Change, College of Forestry, Northwest Agriculture and Forest University, Yangling, Shannxi 712100, China. D.D. Kneeshaw. Centre d'étude de la forêt, Université du Québec a ` Montréal, Case Postale 8888, Succ. Centre-Ville, Montreal, QC H3C 3P8, Canada. G.R. Larocque. Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, PO Box 10380, 1055 du P.E.P.S., Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada. X. Lei. Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing, 100091, China. Q. Zhu. Laboratory for Ecological Forecasting and Global Change, College of Forestry, Northwest Agriculture and Forest University, Yangling, Shannxi 712100, China. X. Song. State Key Laboratory of Subtropical Forest Science and Zhejiang Provincial Key Laboratory of Carbon Cycling and Carbon Sequestration in Forest Ecosystems, Zhejiang Agriculture and Forestry University, Lin'an, Zhejiang 311300, China. Q. Tong. FPInnovations, 3800 Wesbrook Mall, Vancouver, BC V6S 2L9, Canada. Corresponding author: Changhui Peng (e-mail: peng.changhui@uqam.ca). *Present address: Earth System Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA. 469 Can. J. For. Res. 43: 469–479 (2013) dx.doi.org/10.1139/cjfr-2012-0320 Published at www.nrcresearchpress.com/cjfr on xx xxx 2013. Can. J. For. Res. Downloaded from www.nrcresearchpress.com by MCGILL UNIVERSITY on 05/03/13 For personal use only.