摘要
瑞典约有55%的土地面积被森林所覆盖。目前,瑞典的森林覆盖没有统一的和地理学上明晰的描述。现存的独立性数据源是Landsat TM和SPOT HRV卫星数据、地图蒙片(map mask)和森林清查样地。它们在一起,使森林变量(如材积和林分年龄)的计算机估计成为可能。这些估计的精确度在像素水平上是低的,但在林分水平上较高。在规划木材资源应如何加以利用或出于监测目的时,这类基于栅格的森林数据对政府来说是有帮助的。本文描述了以有效成本建立森林变量估计全国数据库的生成流程。我们在林分水平上评价了瑞典西南部某地森林变量估计的精确度。结果表明,总材积估计的整体均方根误差为33%,年龄估计的整体均方根误差为23%。
About 55% of the land area in Sweden is covered by forest.Presently,there is no uniform and geographically explicit description of the forest cover for Sweden. Independent data sources already existing are satellite data from Landsat TM and SPOT HRV,map masks and forest inventory plots.Together,they provide the possibility of computing estimates of forest variables such as stem volume and stand age.The accuracy for these estimations will be low on the pixel level,but higher on a stand level.This type of raster-based forest data is useful for authorities when planning how timber resources should be utilized or for monitoring purposes. The production line that was developed to create a countrywide database of forest variable estimates in a cost-efficient way is described.Accuracy of forest variable estimates for an area in southwestern Sweden was assessed at stand level. Results showed 33% overall root mean square error for the estimates of total wood volume,and 23% for the age estimates.
