Douglas-Fir Biomass Allocation and Net Nutrient Pools 15–20 Years after Organic Matter Removal and Vegetation Control
Douglas-Fir Biomass Allocation and Net Nutrient Pools 15–20 Years after Organic Matter Removal and Vegetation Control
复制标题
有机物去除和植被控制 15-20 年后花旗松生物质分配和净养分库
作者：
K. Littke;T. Harrington;S. M. Holub;W. Littke;R. Harrison;E. Turnblom
花旗松（Pseudotsuga menziesiivar.）对太平洋西北部沿海的menziesii（Mirbel）Franco）种植园林进行了集中管理，以提高森林产品的产量。然而，这些管理技术的长期影响在该地区受到的研究关注有限。三个附属的长期土壤生产力研究网站安装在道格拉斯冷杉林，了解有机物去除和植被控制对土壤生产力的影响随着时间的推移。马特洛克和福尔里弗位于美国华盛顿，莫拉拉位于俄勒冈州。有机物去除处理包括传统的树干只收获（BO），整棵树去除（WT），和整棵树加粗木质残体去除（WT+）（瀑布河只）。五年的年度植被控制（AVC）进行了比较，与传统的初始植被控制（IVC）在所有网站的治疗。道格拉斯冷杉生物量分配到树叶，分支，和干成分建模使用15- 20岁的树木从这项研究沿着与5- 47岁的树木从以前的研究在这些网站上。在所有地点，模型预测表明，WT处理的道格拉斯冷杉生物量比BO处理少7.1至9.7 Mg ha−1。在所有地点，AVC处理的道格拉斯冷杉生物量比IVC处理的多1.5至20.5 Mg ha−1。花旗松碳和氮生物量始终较低的WT治疗，但没有显着变化，在整个网站的营养库。AVC治疗导致更大的花旗松营养池，但有一个网站的钙，镁，钾的净损失，由于较低的森林地面和土壤碱阳离子池。虽然WT去除没有显着影响网站营养，在道格拉斯冷杉生物量的减少在所有网站和增加入侵苏格兰扫帚（Cytisus scoparius（L.）链接）生物量在马特洛克表明，保留收获残留物的标准做法是有益的。使用密集的植被控制，以提高花旗松生物量和营养必须保持土壤盐基阳离子的平衡。
Douglas-fir (Pseudotsuga menziesiivar. menziesii (Mirbel) Franco) plantation forests of the coastal Pacific Northwest have been intensively managed to improve the yield of forest products. However, the long-term effects of these management techniques have received limited research attention in this region. Three affiliate Long-Term Soil Productivity study sites were installed in Douglas-fir forests to understand the impacts of organic matter removals and vegetation control on soil productivity over time. Matlock and Fall River are located in Washington, USA and Molalla is located in Oregon. Organic matter removal treatments included traditional bole-only harvest (BO), whole tree removals (WT), and a whole tree plus coarse woody debris removal (WT+) (Fall River only). Five years of annual vegetation control (AVC) was compared with a conventional initial vegetation control (IVC) treatment at all sites. Douglas-fir biomass allocation to foliage, branch, and stem components was modeled using 15- to 20-year-old trees from this study along with 5- to 47-year-old trees from previous studies on these sites. Across all sites, model predictions indicated that the WT treatment had 7.1 to 9.7 Mg ha−1 less Douglas-fir biomass than the BO treatment. There was 1.5 to 20.5 Mg ha−1 greater Douglas-fir biomass in the AVC treatment than in the IVC treatment at all sites. Douglas-fir carbon and nitrogen biomass were consistently lower in the WT treatment, but there were no significant changes in overall site nutrient pools. The AVC treatment resulted in greater Douglas-fir nutrient pools yet there was a net loss in site calcium, magnesium, and potassium due to lower forest floor and soil base cation pools. While WT removals did not significantly affect site nutrition, the decrease in Douglas-fir biomass at all sites and increase in invasive Scotch broom (Cytisus scoparius (L.) Link) biomass at Matlock suggests that the standard practice of retaining harvest residuals is beneficial. The use of intensive vegetation control to improve Douglas-fir biomass and nutrition must be balanced with retaining soil base cations.