Growth responses to planting density and management intensity in loblolly pine plantations in the southeastern USA Lower Coastal Plain
Growth responses to planting density and management intensity in loblolly pine plantations in the southeastern USA Lower Coastal Plain
复制标题
美国东南部沿海平原火炬松人工林的生长对种植密度和管理强度的响应
DOI：
10.1007/s13595-011-0045-7
复制
发表时间：
2011
影响因子：
3
通讯作者：
B. Borders
中科院分区：
文献类型：
--
作者：
Dehai Zhao;Michael B Kane;B. Borders
1995年在美国东南部的下海岸平原建立了一项文化/密度研究，以评估集约化造林和当前操作实践对火炬松人工林在广泛的种植密度（741- 4448株/公顷）范围内的生长和产量的影响。操作制度包括垫料和除草剂的应用在现场准备和施肥在种植和在第八和第12生长季节。集约化管理方案具有额外的完全竞争控制、梢蛾控制和更多的重复施肥处理。方法采用裂区试验设计，对14个样地的平均胸径、平均树高、平均优势高、成活率、林分断面积和林分蓄积量进行了混合效应模型分析。结果在种植后的最初几年内，管理强度和种植密度的影响不显著。在以后的几年里，管理强度和种植密度显着影响响应变量，它们的相互作用只显着的平均胸径（DBH）。胸径对集约经营的反应在最低密度时最大。集约经营使平均胸径、平均高、优势高、林分断面积和蓄积量增大。密集管理的地块在12岁时死亡率更高。平均胸径、平均树高、优势高和成活率对密度的响应为负，而断面积和蓄积对密度的响应为正。然而，种植密度超过2，224棵树/公顷时没有显著差异。·结论结果表明，管理强度和种植密度显着影响火炬松生产力在沿海低平原，和他们的影响是加性的性质，由于一般缺乏相互作用。
Abstract• BackgroundA culture/density study was established in 1995 in the Lower Coastal Plain of the southeastern USA to evaluate the effects of intensive silviculture and current operational practices on the growth and yield of loblolly pine plantations across a wide range of planting densities (741–4,448 trees/ha). The operational regime consisted of bedding and herbicide application in site preparation and fertilizer applications at planting and in the eighth and 12th growing seasons. The intensive management regime had additional complete competition control, tip moths control, and more repeated fertilization treatments.• MethodsThe data from 14 locations from this split-plot experiment design with repeated measurements were analyzed with a mixed-effects model approach in terms of average DBH, average height, average dominant height, survival, stand basal area, and stand volume.• ResultsIn the first few years after planting, there were no significant effects of management intensity and planting density. In later years, both management intensity and planting density significantly impacted response variables, and their interaction was only significant for average diameter at breast height (DBH). Responses to intensive management in DBH were greatest at the lowest planting densities. Intensive management resulted in larger average DBH, average height, dominant height, stand basal area, and volume. Intensively managed plots had more mortality at age 12. There were negative average DBH, average height, dominant height, and survival responses but positive stand basal area and volume responses to increasing planting density. However, there were no significant differences for planting densities above 2,224 trees/ha.• ConclusionsThe results demonstrate that both management intensity and planting density significantly affect loblolly pine productivity in the Lower Coastal Plain, and their effects are additive in nature due to the general lack of interactions.