Growth Decline Linked to Warming-Induced Water Limitation in Hemi-Boreal Forests

Abstract

Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii), sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year) over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.

Diverse responses of forest growth to drought time‐scales in theNorthernHemisphere

“…In fact, some authors suggested that warming-related drought could cause this recent divergence between temperature and growth at high northern latitudes (Barber et al, 2000;Wu et al, 2012). This would explain that these forests (represented by negative loadings in the first three PCs) show negative correlations with the SPEI since higher precipitation corresponds to cloudiness, lower solar radiation and, in general, lower temperature, which is the major constrain of tree growth in these areas.…”

“…Thus, forests that show a short time-scale response to drought are probably affected by periods of summer water stress, which are increasing in frequency and severity as a consequence of global warming (Dai, 2011;Trenberth et al, 2014). Since forests located in humid regions commonly show a low acclimatization to water-deficit conditions (Maherali et al, 2004), even short drought episodes, here illustrated by short SPEI time-scales, are probably affecting forest growth (Wu et al, 2012).…”

Responses of radial growth to temperature in Larix gmelinii of the Da Hinggan Ling under climate warming

“…)和利 用落叶松树轮宽度指数重建夏季温度变化 (Chen et al, 2013), 然而对气候变暖后相同生境的落叶松 生长特性和模式的南北差异研究很少; 最后, 关于 落叶松相关种属的生长与气候变化关系的研究多集 中于与我国临近的西伯利亚地区 (Andreu et al, 2007;Kujansuu et al, 2007;Sano et al, 2009;Wu et al, 2012;Bryukhanova et al, 2013) (Fritts, 1976;吴祥定, 1990), 并用精度为 化越敏感 (Fritts, 1976;Cook & Kairiukstis, 1990) 图4 落叶松年轮宽度指数与温度的相关关系。A, 大兴安岭南部落叶松年轮宽度指数与温度的相关系数。B, 大兴安岭中部 落叶松年轮宽度指数与温度的相关系数。 C, 大兴安岭北部落叶松年轮宽度指数与温度的相关系数。P6, 前一年的6月; P7, 前一年的7月; P8, 前一年的8月; P9, 前一年的9月; P10, 前一年的10月; P11, 前一年的11月; P12, 前一年的12月; BG, 生长季前; CG, 当年生长季; PA, 上年秋季; PG, 上年生长季; PW, 上年冬季; T m , 月/季度平均温度; T max , 月/季度平均最 高温度; T min , 月/季度平均最低温度。 Fig. 4 Correlations between tree-ring width index in Larix gmelinii and temperature.…”

To leak or not to leak? : Land‐Use Displacement and Carbon Leakage from Forest Conservation

“…Together with warmer temperatures, carbon fertilization is assumed to have caused recent increases in global forest growth (McMahon et al 2010). In other regions, higher temperatures and reduced precipitation can cause increased fire frequency and greater vulnerability to pests and diseases, which might constrain plant growth and survival rates (e.g., Wu et al 2012;AndersonTeixeira et al 2013) 4 . Human-induced changes in terrestrial sink and source functions go back to active management and land-use decisions that lead to a reduction or an increase in biomass and carbon stocks.…”