What Drives Conversion of Tropical Forest in Carrasco Province,Bolivia?

本文运用1986～2002年4张中等分辨率的卫星图像，对玻利维亚卡拉斯科省的郁闭林转化（CCF）进行监测。1986～2002年，森林向无林地的年转化率为1．5％。若包含向疏林的转化，则年CCF率为其2倍，达到3．1％。本文在一个空间模型中检验了郁闭林转化的五个预测因子：土地所有权状况、与道路的距离、与村落的距离、地形、和土壤耕作适宜性。结果，在所检验的5个预测因子中，只有3个是郁闭林转化的可靠预测因子：土地所有权状况、与道路的距离、与村落的距离。大学保护区和原住民土地的郁闭林转化明显低于国家公园和无权属土地。此外，空间模型还表示出：森林离道路和村落越远，郁闭林转化越少。地形和土壤耕作适宜性对郁闭林转化缺乏预测能力，因此从此空间模型中排除。

The conversion of closed forest (CCF) in Carrasco Province,Bolivia,is monitored using a series of four midresolution satellite images from 1986 to 2002.The conversion of forests into nonforests from 1986 to 2002 is 1.5% annually.Inclusion of conversions into open forest doubles the annual CCF rate to 3.1%.Five predictors for CCF are tested in a spatial model:land tenure regime,distance from roads, distance from settlements,topography,and soil suitability for farming.Only three out of the five predictors tested are found to be required:land tenure regime,distance from roads,and distance from settlements.University reserve and indigenous land show substantially and significantly less CCF than national park and untitled land.In addition the spatial model shows that the greater the distance of forest from roads or settlements,the less CCF.Topography and soil suitability for farming lack predictive power for CCF and are therefore excluded from the spatial model.