Distribution of tree species can result in many factors including environmental variables, biotic interaction and management. Better understanding of these interacting factors is crucial in planning management interve...Distribution of tree species can result in many factors including environmental variables, biotic interaction and management. Better understanding of these interacting factors is crucial in planning management interventions especially in managed landscapes: this study on the effect of soil properties on tree species distribution in Kilimanjaro, Tanzania will aid in this. Standard tree inventory procedures and soil sampling techniques were used to survey 48 plots from altitudinal level of 680 to 1690 m a.s.l. along 25 km long transect. All trees ≥ 5 cm at DBH were recorded, while soils were sampled from top and subsoils (0 - 20 and 21 - 50 cm depths). Tree species distribution index was assessed through abundance and frequency, while species interaction with environmental variables was assessed using Detrended Correspondence Analysis. Distribution index indicated that 77% of tree species were categorized as rare, while 10% and 13% were categorized as occasional and abundant respectively. Soil organic carbon and moisture content have shown high correlation with tree species (r > 0.8, p < 0.01), while ExMg, soil pH, P, ExCa, ExK, ExNa and bulky density indicated less correlation (r < 0.2, p < 0.001). The DCA-1 axis explained nearly 70% of the relationships between soil properties and tree species distribution: suitability of tree species were influenced by soil properties across the land use systems which exhibited different soil types. Different tree species communities correspond differently with soil properties between the land use systems. Fewer tree species spread in the lowland, which is known to have saline soils. Therefore, despite intensive human management of the landscape, tree species indicated distribution patterns in line with the soil properties.展开更多
[目的]为了提高森林景观模拟的真实性和实用性,为森林景观规划和森林经营管理提供可靠依据。[方法]以新疆霍城县果子沟林场作为试验区,以林区内主要树种雪岭云杉为树木建模对象,以小班为单位对果子沟林场进行三维可视化模拟。通过外业...[目的]为了提高森林景观模拟的真实性和实用性,为森林景观规划和森林经营管理提供可靠依据。[方法]以新疆霍城县果子沟林场作为试验区,以林区内主要树种雪岭云杉为树木建模对象,以小班为单位对果子沟林场进行三维可视化模拟。通过外业测量获取林木的树高、胸径、冠幅以及冠高等测树因子。从冠形和叶片角度入手对雪岭云杉的外形特征进行分析。使用单曲线方程对冠形进行模拟,使用泊松分布模型模拟树叶在树冠内的分布情况。然后,使用林相图提取小班边界。利用外业调查数据和CTS系统构建不同形态的树木模型。通过林分分布规则、小班属性以及林场内植被分布规则对林木的空间分布进行模拟。最后,使用SQL SERVER 2005作为数据管理平台,使用八叉树作为三维场景管理,结合LOD、视点替换、及地形分页等三维场景渲染及优化技术,对果子沟林场进行三维可视化模拟。模拟面积达300 km2,平均帧率20 FPS以上。[结果]模拟结果较好地反映了小班的空间分布格局,直观地体现出小班内部林木的空间位置分布,具有一定的实用价值。展开更多
文摘Distribution of tree species can result in many factors including environmental variables, biotic interaction and management. Better understanding of these interacting factors is crucial in planning management interventions especially in managed landscapes: this study on the effect of soil properties on tree species distribution in Kilimanjaro, Tanzania will aid in this. Standard tree inventory procedures and soil sampling techniques were used to survey 48 plots from altitudinal level of 680 to 1690 m a.s.l. along 25 km long transect. All trees ≥ 5 cm at DBH were recorded, while soils were sampled from top and subsoils (0 - 20 and 21 - 50 cm depths). Tree species distribution index was assessed through abundance and frequency, while species interaction with environmental variables was assessed using Detrended Correspondence Analysis. Distribution index indicated that 77% of tree species were categorized as rare, while 10% and 13% were categorized as occasional and abundant respectively. Soil organic carbon and moisture content have shown high correlation with tree species (r > 0.8, p < 0.01), while ExMg, soil pH, P, ExCa, ExK, ExNa and bulky density indicated less correlation (r < 0.2, p < 0.001). The DCA-1 axis explained nearly 70% of the relationships between soil properties and tree species distribution: suitability of tree species were influenced by soil properties across the land use systems which exhibited different soil types. Different tree species communities correspond differently with soil properties between the land use systems. Fewer tree species spread in the lowland, which is known to have saline soils. Therefore, despite intensive human management of the landscape, tree species indicated distribution patterns in line with the soil properties.
文摘[目的]为了提高森林景观模拟的真实性和实用性,为森林景观规划和森林经营管理提供可靠依据。[方法]以新疆霍城县果子沟林场作为试验区,以林区内主要树种雪岭云杉为树木建模对象,以小班为单位对果子沟林场进行三维可视化模拟。通过外业测量获取林木的树高、胸径、冠幅以及冠高等测树因子。从冠形和叶片角度入手对雪岭云杉的外形特征进行分析。使用单曲线方程对冠形进行模拟,使用泊松分布模型模拟树叶在树冠内的分布情况。然后,使用林相图提取小班边界。利用外业调查数据和CTS系统构建不同形态的树木模型。通过林分分布规则、小班属性以及林场内植被分布规则对林木的空间分布进行模拟。最后,使用SQL SERVER 2005作为数据管理平台,使用八叉树作为三维场景管理,结合LOD、视点替换、及地形分页等三维场景渲染及优化技术,对果子沟林场进行三维可视化模拟。模拟面积达300 km2,平均帧率20 FPS以上。[结果]模拟结果较好地反映了小班的空间分布格局,直观地体现出小班内部林木的空间位置分布,具有一定的实用价值。
