干旱河谷地区退耕还林调查与生态还林分析

退耕还林工作全面展开已经有4~5年,其执行效果如何?如何及时总结退耕还林中存在的问题和经验进行更好的退耕还林决策呢?利用遥感和地理信息系统技术结合采访调查,及时的、客观反映了退耕还林的执行情况。本文以长江上游生态脆弱区——川藏边缘的横断山区X县为例,应用“3S”技术对退耕还林的成果进行了监测,得出:由于种种原因,该地区退耕还林中可能上报的退耕面积不实,超出实际退耕面积;耕地中很大比例的坡度小于25o的耕地纳入到退耕地中。研究也分析了退耕还林对当地社会、经济等影响,调查和有关研究证实,大面积退耕还林使该地区财政收入大比例较少,农民对国家的补贴依赖性强,一旦停止钱粮补助,农民将失去生活来源,很可能导致毁林复耕。多数农户强烈表达了希望延长粮食补助的愿望,本研究认为经济补偿机制的关键应该放在如何调动农民调整产业结构和发展后续产业的积极性上,否则再长时间的连续补偿也无济于事。对已经大面积退耕的区域,加紧发展后续产业和产业结构调整势在必行,对正在计划退耕的地区,应该将退耕还林作为一个系统工程考虑,退耕还林应该是一个长期的、逐步实施的过程,必须综合各种原则和因素、分清楚轻重缓急,一步步实施,相应的经济补偿机制也需要调整。

Investigation and Analysis of Farmland Afforestation by RS and GIS in Western of Sichuan Province, China

It had been fouror five years since the beginning of practiceof conversion farmlands to forest.But how about the effect of that implementation? According to the survey results coming from different periods of remote sensing data(one in 1999,the other in 2003),some conclusions were drawn as follows: ①In order to get more public subsidyof reforestationor regrassation,the local government often reported the farmlandarea much more than actual reforested area.In our research region,only average 25.4%(the bias of estimation is-15.4%) of farmlandsarea had been reforested actually,however,the local government reported that was 51.98%.②The most serious problems in the reforestation are: only choosing canopy forest species(most of them are climax species) in reforesting;Planting few pure tree speciesin the whole region and not considering the adaptation of variation ecotype to different local environment conditions.we surveyed and discussed the effect of farmland afforestation on local economy and society.The impacts of the farmland afforestation on local societyand local economy were also reported and discussed.This research discussedthe current state and the problems and found neither general income increase nor income structure improvement.These findings raise concerns oneconomic sustainability of the program.According to the results of remote sensing investigation and field-inventory data,how to make use of some theories of ecology and theirs applications to reforestation in local region was analyzed.