Effect of Vegetation Management and Site Conditions on Volume, Biomass and Leaf Area Allometry of Four Coniferous Species in the Pacific Northwest United States
Effect of Vegetation Management and Site Conditions on Volume, Biomass and Leaf Area Allometry of Four Coniferous Species in the Pacific Northwest United States
复制标题
植被管理和立地条件对美国西北太平洋地区四种针叶树种体积、生物量和叶面积异速生长的影响
作者：
C. Gonzalez;Herman N. Flamenco;M. Wightman
异速生长方程是计算树木和林分水平属性（例如地上生物量或茎体积）的有用工具，使用可从林分库存数据获得的简单测量值。这些方程往往是特定于物种的，并且可能受到场地条件和造林处理的影响。森林植被管理措施（VM）是美国西北太平洋地区重新造林计划的重要组成部分；然而，还没有研究调查这些处理对作物树木异速生长的影响。在这项研究中，我们评估了两种对比 VM 处理对生长在俄勒冈州中部海岸山脉 (CR) 的 16 年树龄花旗松、西部铁杉、西部红杉和大冷杉树以及生长在俄勒冈州喀斯喀特山麓 (CF) 的 15 年树龄花旗松和西部红杉树的异速生长的长期影响。 VM处理包括仅接受种植前除草剂施用的对照和由种植后连续五年的植被控制组成的VM处理。本研究中建立的方程是特定于物种的，除西部红杉叶子生物量外，不受 VM 的影响。对于西部红雪松，种植后在没有 VM 的地块上生长时，直径相似的树丛具有更多的叶子生物量。花旗松和西部红杉的异速生长也受到地点的影响，直径和高度相似的树木在 CR 地点生长时比在 CF 地点生长时具有更大的茎体积。发现阀杆体积的差异是阀杆锥度差异的结果。林分断面积和叶面积指数之间存在很强的关系，对于所有测试的物种来说都是相同的，并且不受地点的影响。本研究中提出的方程可用于计算年龄相似的研究物种的茎体积、叶面积以及单株树和组成生物量。
Allometric equations are useful tools for calculating tree and stand-level attributes, such as above-ground biomass or stem volume, using simple measurements that can be obtained from stand inventory data. These equations tend to be species-specific and can be affected by site conditions and silvicultural treatments. Forest vegetation management treatments (VM) are an important component of reforestation programs in the Pacific Northwest of the United States; however, no study has investigated the impact of these treatments on crop tree allometry. In this study we assessed the long-term effects of two contrasting VM treatments on the allometry of sixteen-year-old Douglas-fir, western hemlock, western redcedar, and grand fir trees growing in Oregon’s central Coast Range (CR) and fifteen-year-old Douglas-fir and western redcedar trees growing in Oregon’s Cascade foothills (CF). The VM treatments included a control which received only a pre-planting herbicide application and a VM treatment consisting of five consecutive years of vegetation control after planting. The equations developed in this study were species-specific and were not affected by VM with the exception of western redcedar foliage biomass. For western redcedar, tress of similar diameter had more foliage biomass when growing on plots without VM after planting. The allometry of Douglas-fir and western redcedar was also found to be affected by site, such that trees of similar diameter and height had larger stem volume when growing at the CR site than the CF site. This difference in stem volume was found to be the result of differences in stem tapering. There was a strong relationship between stand basal area and leaf area index that was the same for all species tested and was unaffected by site. The equations presented in this study are useful for calculating stem volume, leaf area and individual tree and component biomass for stands of the studied species that are of similar age.