为准确掌握广东省森林干扰与森林恢复的动态特征,文章基于谷歌地球引擎(Google Earth Engine,GEE)云平台构建Landsat长时序年度无云地表反射率影像集,采用LandTrendr(Landsat-based detection of Trends in Distur-bance and Recovery)...为准确掌握广东省森林干扰与森林恢复的动态特征,文章基于谷歌地球引擎(Google Earth Engine,GEE)云平台构建Landsat长时序年度无云地表反射率影像集,采用LandTrendr(Landsat-based detection of Trends in Distur-bance and Recovery)算法提取广东省1990—2020年森林干扰与森林恢复的时空分布特征,并分析其演变的驱动因素,比较不同森林类型的干扰与恢复特征。结果表明:(1)1990—2020年,广东省的森林干扰总面积约为1.35×10^(4)km^(2),集中分布在广东省西部、东部和中部小范围地区,干扰面积最大的3个城市分别为韶关、梅州、清远市;森林恢复总面积约为1.91×10^(4)km^(2),集中分布在广东省北部和西部地区,恢复面积最大的3个城市分别为韶关、清远、肇庆市。(2)广东省森林干扰与森林恢复均集中发生在海拔小于等于600 m的地区,高海拔地区的森林面积较为稳定;广东省森林干扰集中发生在坡度小于等于25°的地区,森林恢复集中发生在坡度小于等于35°的地区。(3)广东省森林干扰在1996年后发生较为频繁,其中2011年的森林干扰面积最大;森林恢复主要集中在2001—2016年,其中2012年的森林恢复面积最大。(4)广东省的森林干扰与森林恢复主要受雨雪冰冻灾害、台风、病虫害等自然因素以及森林火灾、城市化、采伐、林业政策等人为因素的综合影响,其中雨雪冰冻灾害对广东省北部地区的常绿针叶林的影响较大,但该类型的森林恢复也较快。展开更多
Western Sichuan sub-alpine is an extension of Qinghai-Tibet Plateau to southeastern China and is covered with forests in the valleys, mainly dark coniferous ones. As a result of long-term over-logging on a large scale...Western Sichuan sub-alpine is an extension of Qinghai-Tibet Plateau to southeastern China and is covered with forests in the valleys, mainly dark coniferous ones. As a result of long-term over-logging on a large scale, they have been greatly reduced and degraded. In this paper, in order to analyse the influences of forest management and topography factors on sub-alpine forest restoration in west Sichuan, Miyaluo was selected as a case study area. The cutting volume, artificial regeneration area and tending area from 1953 to 2000 were collected, forest survey and plot investigation were taken in 7 watersheds. The results showed that sub-alpine forest restoration in west Sichuan was influenced by both forest management and natural regeneration. Taking Miyaluo as an example, forest management could be divided into two stages, cutting period (1953—1978) and restoration period (1978—now), and cutting period also could be divided into period Ⅰ (1953—1965) and period Ⅱ (1966—1978). In cutting period with logging on a large scale and fast regeneration, artificial regeneration could not catch up with cutting, tending could not catch up with regeneration, the young growth tending was worse and survival rate was low, especially in period Ⅰ. That resulted in the mosaic patch of plantations, natural secondary forests and ones from both artificial and natural regeneration in cutting area. The pattern was influenced by aspect. Spruce from artificial regeneration was dominant on half-sunny and sunny slope; birch and firs from natural regeneration were on half-shady and shady slopes. In restoration period, cutting was little and stopped at last, artificial regeneration was little; survival rate was high from well tending to young growth. Spruce regenerated artificially in 1980s and at the beginning of 1990s had closed to young forests after successive tending with many years. In sub-alpine forest regions, the regeneration methods and species should be selected according to the habitat types that changed with altitude and aspect. In the sites that restoration can be go on naturally, natural regeneration should be promoted to ensure the persistence and stability of forests.展开更多
文摘为准确掌握广东省森林干扰与森林恢复的动态特征,文章基于谷歌地球引擎(Google Earth Engine,GEE)云平台构建Landsat长时序年度无云地表反射率影像集,采用LandTrendr(Landsat-based detection of Trends in Distur-bance and Recovery)算法提取广东省1990—2020年森林干扰与森林恢复的时空分布特征,并分析其演变的驱动因素,比较不同森林类型的干扰与恢复特征。结果表明:(1)1990—2020年,广东省的森林干扰总面积约为1.35×10^(4)km^(2),集中分布在广东省西部、东部和中部小范围地区,干扰面积最大的3个城市分别为韶关、梅州、清远市;森林恢复总面积约为1.91×10^(4)km^(2),集中分布在广东省北部和西部地区,恢复面积最大的3个城市分别为韶关、清远、肇庆市。(2)广东省森林干扰与森林恢复均集中发生在海拔小于等于600 m的地区,高海拔地区的森林面积较为稳定;广东省森林干扰集中发生在坡度小于等于25°的地区,森林恢复集中发生在坡度小于等于35°的地区。(3)广东省森林干扰在1996年后发生较为频繁,其中2011年的森林干扰面积最大;森林恢复主要集中在2001—2016年,其中2012年的森林恢复面积最大。(4)广东省的森林干扰与森林恢复主要受雨雪冰冻灾害、台风、病虫害等自然因素以及森林火灾、城市化、采伐、林业政策等人为因素的综合影响,其中雨雪冰冻灾害对广东省北部地区的常绿针叶林的影响较大,但该类型的森林恢复也较快。
文摘Western Sichuan sub-alpine is an extension of Qinghai-Tibet Plateau to southeastern China and is covered with forests in the valleys, mainly dark coniferous ones. As a result of long-term over-logging on a large scale, they have been greatly reduced and degraded. In this paper, in order to analyse the influences of forest management and topography factors on sub-alpine forest restoration in west Sichuan, Miyaluo was selected as a case study area. The cutting volume, artificial regeneration area and tending area from 1953 to 2000 were collected, forest survey and plot investigation were taken in 7 watersheds. The results showed that sub-alpine forest restoration in west Sichuan was influenced by both forest management and natural regeneration. Taking Miyaluo as an example, forest management could be divided into two stages, cutting period (1953—1978) and restoration period (1978—now), and cutting period also could be divided into period Ⅰ (1953—1965) and period Ⅱ (1966—1978). In cutting period with logging on a large scale and fast regeneration, artificial regeneration could not catch up with cutting, tending could not catch up with regeneration, the young growth tending was worse and survival rate was low, especially in period Ⅰ. That resulted in the mosaic patch of plantations, natural secondary forests and ones from both artificial and natural regeneration in cutting area. The pattern was influenced by aspect. Spruce from artificial regeneration was dominant on half-sunny and sunny slope; birch and firs from natural regeneration were on half-shady and shady slopes. In restoration period, cutting was little and stopped at last, artificial regeneration was little; survival rate was high from well tending to young growth. Spruce regenerated artificially in 1980s and at the beginning of 1990s had closed to young forests after successive tending with many years. In sub-alpine forest regions, the regeneration methods and species should be selected according to the habitat types that changed with altitude and aspect. In the sites that restoration can be go on naturally, natural regeneration should be promoted to ensure the persistence and stability of forests.
