Potential impacts of regional climate change on site productivity of Larix olgensis plantations in northeast China

Abstract

© iForest -Biogeosciences and Forestry IntroductionUnderstanding how climate change affects forest site productivity is of great importance for adaptive forest management under climate change conditions. Forest site productivity, as a quantitative estimate of the potential for producing plant biomass at a site, is a significant indicator of forest quality, as well as an important variable of forest growth models in forest management (Skovsgaard & Vanclay 2008). However, site productivity presents great spatial and temporal variability (Skovsgaard & Vanclay 2013). Climate change directly or indirectly affects forest productivity due to rising atmospheric CO2 concentration and temperatures, changes in the amount and timing of precipitation and the interactions of forest ecosystems (Kirilenko & Sedjo 2007, Medlyn et al. 2011. Experiments, observations and models indicate that the forest productivity changes with climate change, but the direction and magnitude of the effects are still uncertain (Medlyn et al. 2011). Using dominant height as a measure of site productivity, Bontemps et al. (2009) reported an increase of more than 50% in common beech at the end of the 20 th century in north-eastern France, whereas Badeau et al. (1995) found an increase of 27%. Charru et al. (2010) found an increase of 27.8% in stand basal area increment between 1977 and 1987, and a decrease of approximately 5% between 1987 and 2004. Both positive and negative estimated impacts on forest growth have been reported depending on the climate scenarios employed (Lutz et al. 2013).One of the most widely used indicators of forest site productivity in forest management is the site index (SI), which is the mean height of the dominant trees growing on a site at a reference age (Carmean 1975, Skovsgaard & Vanclay 2008. The site index is assumed to be constant over time, and thus included as a driving variable in forest growth and yield models. In reality, the site index often varies greatly due to changes in the genetic make-up of stands, climatic conditions and management practices (Monserud & Rehfeldt 1990, Valentine 1997, Weiskittel et al. 2011). Empirical models have been developed to estimate the site index from climate, soil and vegetation information, thus allowing the possibility of predicting changes in the site index, forest growth and forest yield under climate change (McKenney & Pedlar 2003, Nigh et al. 2004, Monserud et al. 2006, 2008, Albert & Schmidt 2009, Aertsen et al. 2011, Nothdurft et al. 2012. The climate variables that influence the site index vary with species and sites, as do the magnitude of these variables (Messaoud & Chen 2011). Nigh et al. (2004 developed climate-sensitive site index models of three species (spruce, lodgepole pine and Douglas fir) in the interior of British Columbia, Canada. They found that the site index for all species increased as the temperature rose, and that site index increased with precipitation for the two latter species. Monserud et al. (2006) found that the strongest linear predictors of site...

Spatial Heterogeneity of Climate Change Effects on Dominant Height of Larch Plantations in Northern and Northeastern China

“…Although temperature is also a key factor in forest growth [48,49], the correlation between temperature and forest growth was inconsistent in previous studies, even for larch in China. Shen et al [30] found an opposite result to the present study, i.e., that temperature showed a negative effect on site index of Larix olgensis in Jilin, China. However, Zhang et al [49] found a significantly positive correlation between temperature and tree-ring width for Dahurian larch in Inner Mongolia, northeastern China.…”

“…PWM showed a positive effect on the maximum dominant height, and TWQ showed a positive effect on the rate of dominant height growth. Many studies have found that precipitation is a key factor that has often been shown to have positive effects on the growth of larch plantations [30,47]. For example, the positive effects of precipitation on stand dominant height growth were also found for jack pine and black spruce [24], and these findings are consistent with those of the present study.…”

“…Uncertainty in the model prediction of dominant height/site index under climate change was also observed in previous studies. Shen et al [30] found that the average site index of Larix olgensis A. Henry ranged from 0.3 m (2.2%) to´0.8 m (´5.9%) by 2050 and from 0.5 m (3.7%) to´1.6 m (´11.8%) by 2070 in Jilin province, China. Albert and Schmidt [55] predicted a change in site index for the period 2041-2050 that varied from´1.19 m to´2.87 m (´4.4% to´10.5%) with decreasing precipitation and from´0.24 m to 2.05 m (´0.8% to 7.7%) with increasing temperature.…”

“…New growth models that incorporate climate variables may be the first step in providing pivotal information on how to adapt to climate change. Shen et al [30] developed a climate-sensitive site index model for Jilin Province (mid-northeastern China). As forest response to climate change differs according to social conditions [31] and the extreme topographical conditions in northern and northeastern China, it is necessary to assess the spatial heterogeneity so as to include specific adaption measures in forest management.…”

Impacts of climate change on the potential forest productivity based on a climate-driven biophysical model in northeastern China

“…Zhao et al (2009Zhao et al ( , 2011 predicted that the NPP of coniferous and broad-leaf mixed forests in northeastern China had an increasing trend under future climate warming, using the GLOPEM-CEVSA model. Shen et al (2015) studied the potential impacts of regional climate change on productivity of Larix olgensis in northeastern China using a generalized additive model (GAM) and found that the change of mean site productivity of Larix olgensis would vary from 2.2 to -5.9% by 2050 and from 3.7 to -11.8% by 2070 under three BC-RCP scenarios with rising temperature and increasing precipitation. Although all RCPs scenario simulations indicated that forest PP would increase by the end of this century in response to future climate changes, the magnitude of this increase varies markedly among different areas (PP increased by 8.19-15.30% in SE, 1.38-9.36% in CB, 3.48-11.56% in SW from the present to 2070).…”