Ramezani Habib, Ramezani Farhad
Department of Forest Resource Management, Swedish University of Agricultural Sciences, SLU, SE-901 83, Umeå, Sweden,
Environ Monit Assess. 2015 Mar;187(3):116. doi: 10.1007/s10661-015-4283-2. Epub 2015 Feb 18.
National forest inventories (NFIs) have traditionally been designed to assess the production value of forests as well as forest biodiversity. However, in this study, the aim is to show a new application of NFIs, namely the estimation of the landscape metric contagion. This metric is commonly calculated on raster-based land cover/use maps. In this study, a sample-based dataset from the Swedish NFI was used. The estimated contagion metric is based on a distance-dependent function so that the value of the metric is small for longer distances, whereas the corresponding estimated variance is large for longer distances. With this procedure, comparisons can be made for different landscapes at a given time and or to compare any given landscape over time. The main advantages are that the approach can be applied where raster-based land cover/use maps of the landscape are not available and that the data obtained from NFIs (e.g., land cover type) typically are of high quality in comparison with remotely sensed data due to being based on direct observation in the field survey. The procedure applied here accommodates both the patch-mosaic and the gradient-based model approach to landscape structure.
国家森林资源清查（NFIs）传统上旨在评估森林的生产价值以及森林生物多样性。然而，在本研究中，目的是展示国家森林资源清查的一种新应用，即景观指标蔓延度的估算。该指标通常是在基于栅格的土地覆盖/利用地图上计算的。在本研究中，使用了来自瑞典国家森林资源清查的基于样本的数据集。估算的蔓延度指标基于距离相关函数，因此对于较长距离该指标的值较小，而相应的估算方差对于较长距离则较大。通过此程序，可以在给定时间对不同景观进行比较，或者比较任何给定景观随时间的变化。主要优点是该方法可以应用于没有景观的基于栅格的土地覆盖/利用地图的情况，并且与遥感数据相比，从国家森林资源清查中获得的数据（例如土地覆盖类型）通常由于基于实地调查中的直接观测而具有高质量。这里应用的程序兼顾了景观结构的斑块镶嵌和基于梯度的模型方法。
