北方带、温带和热带森林斑块的森林结构和坠落的木质碎片  

Forest Structure and Downed Woody Debris in Boreal,Temperate,and Tropical Forest Fragments

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

机构地区：[1]美国林业局FS国际热带林业研究所 [2]USDA FS的ⅡTF兼任波多黎各大学里约彼德拉斯校园生物系教师 [3]美国农业部林业局洛矶山研究站莫斯科林业科学实验室 [4]USDA FS北方生态合作研究组太平洋西北研究站 [5]博南扎溪Bonanza Creek长期生态研究长期生态研究计划的项目经理 [6]中国

出　　处：《AMBIO－人类环境杂志》2008年第7期507-517,539,共11页

摘　　要：森林破碎化丰富了森林类型多样性,增加了森林边缘长度,从而影响了累计可燃物的异质性。这种异质性影响我们如何管理可燃物、火灾和森林。理解沿气候梯度,以及在同一气候带里的木质生物量破碎化的相对重要性,将提高我们管理森林可燃物及预测森林火灾的能力。本研究沿北方带、温带和热带的气候梯度,按不同湿度,即干旱林和潮湿林;不同结构,即开放冠层(年轻的)对郁闭冠层(年老的);不同大小,即小型(10～14hm^2)、中型(33～60hm^2)、大型(100～240hm^2),来评估林段中森林可燃物的特点。沿斑块林边缘,我们由外向内测定了一系列横断面样地的半腐层、枯枝落叶层、细碎和粗糙木质残体、死立木和活体生物量。本研究目的是确定沿森林横断面纵深的森林结构和可燃物的特点有何不同,并是否随温度、湿度、结构和斑块大小的变化而有所不同。结果表明,粗木质残体、细木质残体、死立木和活体树木生物量与年平均温度值之间不存在线性关系。温带的生物量最大。北方带森林的地面可燃物(半腐层和枯枝落叶层)与温度和生物量之间呈线性关系。我们对数据进行5维多因素方差分析后发现,温度、湿度和年龄/结构对森林地面可燃物、落下的木质碎片以及活体树木生物量均有重大影响。斑块大小影响了森林地面燃料生物量和活树生物量。距离森林边缘的远近仅在一些样本体中影响明显。但也有一些例外的情况,即森林边缘和内部没有明显的区别。Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges.This heterogeneity has implications in how we manage fuels,fire,and forests.Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients,will improve our ability to manage forest fuels and predict fire behavior.In this study we assessed forest fuel characteristics in stands of differing moisture,i.e.,dry and moist forests,structure,i.e.,open canopy (typically younger) vs.closed canopy (typically older) stands,and size,i.e.,small (10-14 ha), medium (33 to 60 ha),and large (100-240 ha) along a climatic gradient of boreal, temperate,and tropical forests.We measured duff,litter,fine and coarse woody debris,standing dead,and live biomass in a series of plots along a transect from outside the forest edge to the fragment interior.The goal was to determine how forest structure and fuel characteristics varied along this transect and whether this variation differed with temperature,moisture,structure,and fragment size.We found nonlinear relationships of coarse woody debris,fine woody debris,standing dead and live tree biomass with mean annual median temperature.Biomass for these variables was greatest in temperate sites.Forest floor fuels (duff and litter) had a linear relationship with temperature and biomass was greatest in boreal sites.In a five-way multivariate analysis of variance we found that temperature,moisture, and age/structure had significant effects on forest floor fuels,downed woody debris, and live tree biomass.Fragment size had an effect on forest floor fuels and live tree biomass.Distance from forest edge had significant effects for only a few subgroups sampled.With some exceptions edges were not distinguishable from interiors in terms of fuels.

关 键 词：粗木质残体 森林结构 斑块大小 热带森林 北方 温带 森林可燃物 枯枝落叶层 

分 类 号：S715[农业科学—林学] S718.5