湿润及干旱的北方带、温带、热带森林斑块中美洲山杨木(Populus tremuloides Michx.)的腐烂分解  

Decay of Aspen(Populus tremuloides Michx.)Wood in Moist and Dry Boreal,Temperate,and Tropical Forest Fragments

作　　者：Grizelle González William A．Gould Andrew T．Hudak Teresa Nettleton Hollingsworth 刘琪（译） 王大伟（译） 

机构地区：[1]美国农业部USDA林业局FS国际热带森林研究所ⅡTF [2]美国农业部林业局落基山脉研究站莫斯科林业科学实验室 [3]中国

出　　处：《AMBIO－人类环境杂志》2008年第7期518-527,共10页

摘　　要：本研究对山杨木的腐烂分解进行了实验:1)量化了湿润及干旱的北方带(美国阿拉斯加和明尼苏达)、温带(美国华盛顿和爱达荷)热带(波多黎各)森林类型中美洲山杨木桩(Populustremuloides)的总量残留百分比、分解常数和性能强度;2)因为斑块大小、森林年龄(和/或结构)以及大中等尺度上的气候均与木材的分解相关,测定了斑块化对木材分解速率的影响。斑块大小代表了某一气候地区的景观变化程度。总的说来,小斑块的平均面积为10～14hm^2,中等斑块的为33～60hm^2,大斑块的为100～240hm^2。结果发现:1)热带山杨木桩分解最快,温带最慢;2)在北方带和温带斑块中,干旱林的总量残留百分比显著高于潮湿林的,而在热带斑块中则相反;3)在北方带、温带干旱和热带潮湿林中,森林斑块大小不影响杨木桩的总量残留百分比;4)北方带、温带和热带斑块的边缘和内部,杨木分解没有显著差异。本研究结论如下:1)在广阔的气候梯度下,水汽条件是木材分解的重要控制因素,而且二者之间关系可能是非线性的;2)特殊有机体的存在(白蚁)可能会比单凭气候因子预测的更明显地改变木材分解速率。对木材分解的生物防治可能更是热带地区木材分解的重要预测指标,而非生物限制似乎是寒冷森林斑块木材分解的重要决定因素。In this study,we set up a wood decomposition experiment to i) quantify the percent of mass remaining,decay constant and performance strength of aspen stakes (Populus tremuloides) in dry and moist boreal (Alaska and Minnesota,USA),temperate (Washington and Idaho,USA),and tropical (Puerto Rico) forest types,and ii) determine the effects of fragmentation on wood decomposition rates as related to fragment size,forest age (and/ or structure) and climate at the macro- and mesoscales. Fragment sizes represented the landscape variability within a climatic region. Overall,the mean small fragments area ranged from 10-14 ha,medium-sized fragments 33 to 60 ha,and large fragments 100-240 ha.We found that:i) aspen stakes decayed fastest in the tropical sites,and the slowest in the temperate forest fragments,ii) the percent of mass remaining was significantly greater in dry than in moist forests in boreal and temperate fragments,while the opposite was true for the tropical forest fragments,iii) no effect of fragment size on the percent of mass remaining of aspen stakes in the boreal sites,temperate dry,and tropical moist forests, and iv) no significant differences of aspen wood decay between forest edges and interior forest in boreal,temperate and tropical fragments.We conclude that:i) moisture condition is an important control over wood decomposition over broad climate gradients;and that such relationship can be non linear,and ii) the presence of a particular group of organism (termites) can significantly alter the decay rates of wood more than what might be predicted based on climatic factors alone.Biotic controls on wood decay might be more important predictors of wood decay in tropical regions,while abiotic constraints seems to be important determinants of decay in cold forested fragments.

关 键 词：斑块大小 热带森林 腐烂分解 温带 北方 干旱 杨木 湿润 

分 类 号：S718.54[农业科学—林学] Q149[生物学—生态学]