Climate‐diameter growth relationships of black spruce and jack pine trees in borealOntario,Canada

Abstract

To predict the long-term effects of climate change - global warming and changes in precipitation - on the diameter (radial) growth of jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] B.S.P.) trees in boreal Ontario, we modified an existing diameter growth model to include climate variables. Diameter chronologies of 927 jack pine and 1173 black spruce trees, growing in the area from 47°N to 50°N and 80°W to 92°W, were used to develop diameter growth models in a nonlinear mixed-effects approach. Our results showed that the variables long-term average of mean growing season temperature, precipitation during wettest quarter, and total precipitation during growing season were significant (alpha = 0.05) in explaining variation in diameter growth of the sample trees. Model results indicated that higher temperatures during the growing season would increase the diameter growth of jack pine trees, but decrease that of black spruce trees. More precipitation during the wettest quarter would favor the diameter growth of both species. On the other hand, a wetter growing season, which may decrease radiation inputs, increase nutrient leaching, and reduce the decomposition rate, would reduce the diameter growth of both species. Moreover, our results indicated that future (2041-2070) diameter growth rate may differ from current (1971-2000) growth rates for both species, with conditions being more favorable for jack pine than black spruce trees. Expected future changes in the growth rate of boreal trees need to be considered in forest management decisions. We recommend that knowledge of climate-growth relationships, as represented by models, be combined with learning from adaptive management to reduce the risks and uncertainties associated with forest management decisions.

Integrating regional climate change into allometric equations for estimating tree aboveground biomass of Masson pine in China

“…Previous studies indicated that the relationship between mean annual precipitation and tree AGB or net primary productivity, on the most of sites, could be described by a nonlinear, concave-down function (Hsu et al 2012). The decline in the AGB was likely an indirect effect mediated by the availability of other resources (Hsu et al 2012;Subedi and Sharma 2013). While additional moisture usually increases tree biomass in dry-to-mesic ecosystems, increasing precipitation in humid ecosystems may reduce tree biomass by decreasing radiation, increasing nutrient leaching, or reducing soil oxygen availability (Schuur 2003;Hsu et al 2012).…”

“…While additional moisture usually increases tree biomass in dry-to-mesic ecosystems, increasing precipitation in humid ecosystems may reduce tree biomass by decreasing radiation, increasing nutrient leaching, or reducing soil oxygen availability (Schuur 2003;Hsu et al 2012). Increasing precipitation may also reduce the diffusion of oxygen through water-filled pores, as well as decomposition rates (Subedi and Sharma 2013). In addition, the results that an increase in precipitation led to the decrease of AGB could be also explained by biological traits of Masson pine.…”

“…The climatic impacts on AGB of each sample tree under climate change scenarios should be then analyzed. However, in practice, in addition to climatic zones and climatic-related variables, other factors, such as tree height, crown size, development stage, forest types, site characteristics, stand structure, stand density (including tree recruitment and death), and competition, might significantly contribute to the variation in the individual tree D (Subedi and Sharma 2013;Ashraf et al 2015). Some of these factors interact with each other and vary with future climate change, which would result in the complexity and very large uncertainty in future AGB estimates of sample trees for this method when D growth is considered.…”

“…Global climate change affects all aspects of forest community structure and ecosystem production, such as seedling establishment (Daniels and Veblen 2004), tree growth and mortality Subedi and Sharma 2013;Lei et al 2016), tree species distribution (Hamann and Wang 2006;Sinervo et al 2010), competition among species (Hamann and Wang 2006;Boisvert-Marsh et al 2014;Monleon and Lintz 2015), and forest biomass and productivity (Jiang et al 2015;Tian et al 2016). Forests play an important role in mitigation of climate change by removing carbon from the atmosphere and storing it in biomass.…”

Responses in allometric growth of two dominant species of subalpine meadow—Arundinella anomala and Miscanthus sinensis—to climate warming in Wugongshan Mountains, China

“…以全球变暖和大气CO 2 浓度升高为主要特征的 全球变化正持续影响着陆地生态系统的结构和功 能, 威胁着人类的生存与健康, 因而备受世界各国 政府和科学家的普遍关注 (Oreskes, 2004;Bellard et al, 2012;Eklöf et al, 2012)。 大量的监测和模型模拟 研究表明, 20世纪开始的全球温室效应不断继续着, 而且有不断扩大的趋势(IPCC, 2007)。 全球平均地表 温度在20世纪已经增加了大约0.6 K (Houghton et al, 2001), 并且在未来几十年可能还会快速地上升 (Zwiers, 2002)。研究表明, 冬春季节增温可显著改 变植物物候 (Morin et al, 2010;Yu et al, 2010;Fu et al, 2015;Wheeler et al, 2015)、生长和功能特征 (Dorji et al, 2013;Subedi & Sharma, 2013)、开花和 繁殖 (Cook et al, 2012)、生理生态 (Fan et al, 2015), et al, 2008), 因此被认为是生物界中普遍存在的一 种规律 (West et al, 1999;Niklas & Enquist, 2002 …”