Evapotranspiration and canopy characteristics of two lodgepole pine stands following mountain pine beetle attack
Evapotranspiration and canopy characteristics of two lodgepole pine stands following mountain pine beetle attack
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DOI：
10.1002/hyp.9870
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发表时间：
2014-04
影响因子：
3.2
通讯作者：
Mathew G. Brown;T. A. Black;Z. Nešić;V. Foord;D. Spittlehouse;A. Fredeen;R. Bowler;N. Grant
中科院分区：
文献类型：
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作者：
Mathew G. Brown;T. A. Black;Z. Nešić;V. Foord;D. Spittlehouse;A. Fredeen;R. Bowler;N. Grant
在过去的十年中，不列颠哥伦比亚省（BC）经历了有记录以来最大的山松甲虫（MPB）爆发。本研究使用涡度相关（EC）技术，以检查的影响MPB攻击的蒸散量（E）和相关的冠层特征的两个lodgepole松树林与二级结构（树木，树苗和幼苗生存的攻击）位于BC中部。MPB‐06是一个85年的几乎纯松树林，于2006年首次受到攻击，到2010年，约80%的树木已经死亡。MPB‐03是一个110年的林分，其上层林由超过90%的松树和发达的子树冠组成，于2003年首次受到攻击，到2007年，松树树冠死亡率超过95%。EC测量于2006年8月在MPB-06和2007年3月在MPB-03开始，并持续了四年。MPB-06的年度总E范围为226 mm至237 mm，MPB-03的年度总E范围为280 mm至297 mm，表明四年来两个地点的年度变化相对较小。增加E从幸存的植被（二级结构，灌木和草本植物）的加速生长补偿减少E由于死亡的上层。月平均日间冠层传导率、Priestley-Taylor（α）和冠层-大气解耦系数（Ω）在生长季节稳步增加，分别达到约5 mm s−1、0.75和0.12的最大值。潜在蒸散量使用在高土壤含水量下获得的取决于蒸汽压亏缺的α来近似。计算出的水分亏缺表明，在两个地点，幸存的树木和林下植物的供水受到一定的限制。在生长季节的根区排水率相对较低的降水。版权所有© 2013约翰威利父子有限公司.
Over the past decade, British Columbia (BC), has experienced the largest mountain pine beetle (MPB) outbreak on record. This study used the eddy‐covariance (EC) technique to examine the impact of the MPB attack on evapotranspiration (E) and associated canopy characteristics of two lodgepole pine stands with secondary structure (trees, saplings and seedlings surviving the attack) located in central BC. MPB‐06, an 85‐year‐old almost pure stand of pine trees, was first attacked in 2006, and by 2010, ~80% of the trees had been killed. MPB‐03, a 110‐year‐old stand with an overstory consisting of over 90% pine and a developed sub‐canopy, was first attacked in 2003 and by 2007 had > 95% pine canopy mortality. EC measurements began in August 2006 at MPB‐06 and in March 2007 at MPB‐03, and continued for four years. Annual total E ranged from 226 mm to 237 mm at MPB‐06, and from 280 to 297 mm at MPB‐03, showing relatively little year‐to‐year change at both sites over the four years. Increased E from the accelerated growth of the surviving vegetation (secondary structure, shrubs and herbs) compensated for reduction in E due to the death of the overstory. Monthly average daytime canopy conductance, the Priestley–Taylor (α), and the canopy–atmosphere decoupling coefficient (Ω) steadily increased during the growing season reaching approximate maximum values of 5 mm s−1, 0.75 and 0.12, respectively. Potential evapotranspiration was approximated using a vapour pressure deficit‐dependent α obtained at high soil water content. Calculated water deficits indicated some water‐supply limitation to the surviving trees and understory at both sites. Rates of root zone drainage during the growing season were low relative to precipitation. Copyright © 2013 John Wiley & Sons, Ltd.