Dependences of longleaf pine (Pinus palustris) natural reproduction on environments above ground

来源 :Journal of Forestry Research | 被引量 : 0次 | 上传用户:mxf12
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
We studied relations between natural seedling reproduction and above ground environment in a longleaf pine ecosystem. Forty-eight 0.05 ha circular plots were sampled under single-tree selection, grouptree selection and control stands in three main longleaf pine areas in south Alabama, USA. We measured six above-ground environment factors, viz. canopy closure, stand density, basal area, average tree height, understory cover and PAR under canopy. We employed forward, backward and stepwise selection regression to produce one model. Three main variables: canopy closure, stand density and basal area, were left in the model; light, PAR and understory cover were not incorporated into the model at the 0.10 significance level. Basal area was a positive parameter, while canopy closure and stand density were negative parameters. Canopy closure was the main parameter in the model. The model proved to be meaningful, and has potential to provide useful guidance for future work. We studied relations between natural seedling reproduction and above ground environments in a longleaf pine ecosystem. Forty-eight 0.05 ha circular plots were sampled under single-tree selection, grouptree selection and control stands in three main longleaf pine areas in south Alabama, USA. canopy closure, stand density, basal area, average tree height, understory cover and PAR under canopy. We employed forward, backward and stepwise selection regression to produce one model. Three main variables: canopy closure , stand density and basal area, were left in the model; light, PAR and understory cover were not incorporated into the model at the 0.10 significance level. Basal area was a positive parameter, while canopy closure and stand density were negative parameters. Canopy closure was the main parameter in the model. The model proved to be meaningful, and has potential to provide useful guidance for future work.
其他文献
在定性研究方面,一个主要的挑战就是"反面的"案例(如非革命、非战争)的选择.这些案例包含在试图解释可以得到与研究相关的结果(如革命、战争)的分析之中.尽管很多人都认为反
在氮气气氛下利用TG-DSC联用方法对干燥基、空干基和收到基褐煤煤样以及纯水(常态水)进行分析,得到单位质量水分析出所需的能耗曲线.研究结果表明,常态水析出所需能量基本保
采用树脂转移模塑(RTM)工艺制备先进复合材料的关键是高性能树脂基体的选择.以N,N’-二氨基二苯甲烷双马来酰亚胺(BDM)、O,O′-二烯丙基双酚A(DBA)和双酚A型氰酸酯(CE)为树脂
分析不对称接地状态下调节串联电压和串联电感控制线路电流等于正常电流的可能性,并提出一种新型的故障电流控制器,它由并联变压器、串联变压器、可调电感和有载调节开关构成
树脂基复合材料在厚度方向上较低的导电及导热性能限制了其在防静电、电磁屏蔽等领域的应用.采用多壁碳纳米管(MWNTs)改性T700/环氧复合材料,研究了MWNTs对复合材料基本力学
文章分析了绿色建筑的起源和三大特征,对绿色建筑设计观进行了阐述,并对绿色建筑和绿色设计的前景进行了展望。 The paper analyzes the origin and three characteristics
Forest gaps, openings in the canopy caused by death of one or more trees, have a profound effect on forest regeneration and drive the forest growth cycle. It is
轰燃是火灾蔓延的危险信号,尤其是在地下建筑内更容易造成群死群伤事故和巨额财产损失.本文总结归纳了轰燃的主要危害,从理论上分析了火灾荷载密度和开口尺寸对其发生的影响
采用溶胶-凝胶法在不同基体表面制备了叠层式TiO2/SnO2复合纳米薄膜。用扫描电子显微镜(SEM)、X射线衍射(XRD)对复合薄膜表面形貌和晶体结构进行表征。采用紫外-可见吸收光谱
文章报道了塔里木河中游胡杨林土壤原生动物的种类组成、优势类群、相似性系数等,与中国典型地带土壤原生动物进行比较.结果共观察到原生动物5个纲7个目13个属17个种.