Pan William, Carr David, Barbieri Alisson, Bilsborrow Richard, Suchindran Chirayath
Department of International Health, Johns Hopkins Bloomberg School of Public Health.
Popul Res Policy Rev. 2007 Dec 1;26(5-6):635-659. doi: 10.1007/s11113-007-9045-6.
This study tests four hypotheses related to forest clearing over time in Ecuador's northern Amazon: (1) a larger increase in population over time on a farm (finca) leads to more deforestation; (2) rates of forest clearing surrounding four primary reference communities differ (spatial heterogeneity); (3) fincas farther from towns/communities experience lower rates of forest clearing over time; and (4) forest clearing differs by finca settlement cohort, viz., by year of establishment of the finca. In this paper, we examine the relationship between forest clearing and key variables over time, and compare three statistical models-OLS, random effects, and spatial regression-to test hypotheses. Descriptive analyses indicate that 7-15% of forest area was cleared on fincas between 1990 and 1999; that more recently established fincas experienced more rapid forest clearing; and that population size and forest clearing are both related to distance from a major community. Controlling for key variables, model results indicate that an increase in population size is significantly related to more forest clearing; rates of forest clearing around the four major communities are not significantly different; distances separating fincas and communities are not significantly related to deforestation; and deforestation rates are higher among more recently established fincas. Key policy implications include the importance of reducing population growth and momentum through measures such as improving information about and provision of family planning services; increasing the low level of girls education to delay and reduce fertility; and expanding credit and agricultural extension services to increase agricultural intensification.
(1)随着时间推移,农场(庄园)人口增长幅度越大,森林砍伐就越多;(2)四个主要参考社区周边的森林砍伐率存在差异(空间异质性);(3)随着时间推移,距离城镇/社区较远的庄园森林砍伐率较低;(4)森林砍伐因庄园定居群组而异,即因庄园建立年份而异。在本文中,我们研究了森林砍伐与关键变量随时间的关系,并比较了三种统计模型——普通最小二乘法(OLS)、随机效应模型和空间回归模型——以检验假设。描述性分析表明,1990年至1999年间,庄园上7%至15%的森林面积被砍伐;较新建立的庄园森林砍伐速度更快;人口规模和森林砍伐都与距主要社区的距离有关。在控制关键变量后,模型结果表明,人口规模的增加与更多的森林砍伐显著相关;四个主要社区周边的森林砍伐率没有显著差异;庄园与社区之间的距离与森林砍伐没有显著关系;较新建立的庄园森林砍伐率更高。关键的政策影响包括通过以下措施减少人口增长和增长势头的重要性:改善计划生育服务的信息提供和服务;提高女童教育水平以延迟和降低生育率;扩大信贷和农业推广服务以提高农业集约化程度。