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玻利维亚过去30年土地覆被变化 被引量:1
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作者 Timothy J.Killeen veronica calderon +7 位作者 Liliana Soria Belem Quezada Marc K.Steininger Grady Harper Luis A.Solórzano Compton J.Tucker 田玉军 马国霞 《AMBIO-人类环境杂志》 2007年第B11期565-571,577,共7页
利用5个时段的Landsat图像对玻利维亚东部低地所有山区树木生长线(大约3000m)以下的陆地景观的土地覆被变化进行研究,包括湿润森林、泛滥森林、季节性旱地林、云雾林及灌丛地和草地。2004年玻利维亚东部森林砍伐面积为45 411km^2,大约... 利用5个时段的Landsat图像对玻利维亚东部低地所有山区树木生长线(大约3000m)以下的陆地景观的土地覆被变化进行研究,包括湿润森林、泛滥森林、季节性旱地林、云雾林及灌丛地和草地。2004年玻利维亚东部森林砍伐面积为45 411km^2,大约占原始森林覆盖面积的9%,另外有9042km^2的灌丛、热带稀树草原生境转为它用,占土地覆被总历史变化的17%。玻利维亚土地覆被变化速度从20世纪60年代的400km^2/a上升到2001~2004年间的大约2900km^2/a。本研究为玻利维亚提供监测未来土地覆被变化的可靠空间数据,这是建议的补偿机制,即补偿通过减少森林砍伐来降低碳排放的国家的前提。对比最近和以前各时期的土地覆被变化,发现20世纪90年代颁布的有关森林保护政策并没有对降低森林砍伐起明显的作用,在有些保护区内森林砍伐事实上增加了。全国范围内土地覆被变化的速度继续呈线性上升趋势,但是在圣克鲁斯区上升速度更快,这与该地区动农业机械化和养牛业的扩展有关。 展开更多
关键词 土地覆被变化 玻利维亚 森林覆盖面积 森林砍伐 热带稀树草原 上升速度 补偿机制 上升趋势
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Spanish National Monuments with Traditional Timber Roofs: Restoration versus Reconstruction
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作者 Javier Garabito Jose Carlos Garabito +3 位作者 Victor Echarri Angel Rodriguez Jesus Gadea veronica calderon 《Journal of Civil Engineering and Architecture》 2011年第9期828-834,共7页
We prioritize interventions in the roof structure in order to prevent subsequent deterioration of the monument. This presentation refers to interventions in two Spanish National Monuments: the Collegiate Church of Ro... We prioritize interventions in the roof structure in order to prevent subsequent deterioration of the monument. This presentation refers to interventions in two Spanish National Monuments: the Collegiate Church of Roa de Duero and San Esteban's church of Los Balbases. The Collegiate Church was built during the 16th century. It is considered the jewel of the villa. It is a "hallenkirche" model with three big naves of the same height covered by beautiful starry vaults. The intervention consisted of restoring the wooden roof structure, preserving the original 16th centary structure, by replacing the damaged elements. It was restored according to archaeological criteria. San Esteban's church is a 13 century Gothic style church with a Latin cross plan. It has three naves with a transept of great slenderness. It preserves Romanesque remains. Opposite to the previous intervention we decided to rebuild the roof because the former roof was totally distorted due to bad executed works during the past Century. In this way we regain the original shape of the church. These interventions aim to improve constructive and structural conditions as well as retrieve the image of both monuments. We have studied the visual impact of interventions through virtual recreations. The intervention criteria are very different, restoration versus structttral reconstruction. 展开更多
关键词 RESTORATION ROOF timber structure HERITAGE laminated wood.
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