林带空间配置与布局优化研究

农田防护林(林带)的空间配置与布局是影响防护林结构和防护效益发挥并持续的关键因素．为达到农田防护林防护效益最大并持续的经营目标。在保证林分多样性和稳定性的条件下．林带必须具有空间上布局的合理性和时间上的连续性．经过多年防护林营林研究实践．在对1992年于辽宁省昌图县双井子乡设计营造的试验示范林带调查的基础上．对农田防护林单条林带方向的设置、带内树木的空间搭配方式、树种组成形式，多条林带或林网的带间距离以及大面积或区域防护林体系的空间景观布局等进行了综合研究．结果表明，单条林带和林网走向都应以垂直主害风作为设计的原则；林带内树木的空间搭配以“品”字型为佳，在不同树种混交的同一条林带中，可利用“边行优势”将生长相对缓慢的树种配置于边行．生长相对迅速的树种配置于内行；多条林带或林网空间配置参数——带间距离的设计应以林带达到初始防护成熟龄时的树高作为成林高．以林带结构变化规律和降低害风比例作为林带设计关键参数；区域防护林体系的空间布局应以景观生态学原理为基础．对林网体系进行评价与调控．

Optimization of spatial arrangements and patterns for shelterbelts or windbreaks

Spatial arrangements and patterns of shelterbelts or windbreaks are the key factors influencing the shelterbelt structures, shelter benefits, and shelterbelt sustainability. In order to keep the shelter benefits and achieve the sustainability of shelterbelts, it is necessary to keep the reasonable arrangements and patterns in spatiality and the continuation in time. Based on the investigations on the shelterbelts, which were established in 1992 as the models in Shuangjingzi Township, Changtu County, Liaoning Province, and combined with the experiences and practices of shelterbelt management, the authors studied and summarized the arrangements and patterns of shelterbelts, which included the direction of a single shelterbelt and shelterbelt networks, the arrangement of tree composition in a shelterbelt, and the mixture of tree species for shelterbelts. Additionally, the spacing intervals between shelterbelt and the spatial patterns for regional shelterbelts were also discussed. The results indicated that the direction of both single shelterbelt and shelterbelt networks should be perpendicular to the disaster winds. It is better for the structure of a shelterbelt to arrange the trees in triangle form in a shelterbelt. According to the edge effect, the tree species which grow slowly should be arranged in the edge lines, but the tree species which grow fast should be arranged in the inner lines of the mixed shelterbelts. Optimal spacing intervals between windbreaks could be predicted from the indices of a given windbreak structure (porosity), percentage of desired wind speed reduction, and tree growth model (model for determining initial protective maturity age). The patterns of shelterbelts in large scale should be evaluated and arranged according to the principles of landscape ecology. The results mentioned above would provide the evidences for shelterbelt sustainable management.