Ground monitoring the light-shadow windows of a tree canopy to yield canopy light interception and morphological traits

被引:52
作者
Giuliani, R
Magnanini, E
Fragassa, C
Nerozzi, F
机构
[1] Univ Bologna, Dipartimento Colture Arboree, I-40126 Bologna, Italy
[2] ARPA, Serv Meteorol Reg, I-40122 Bologna, Italy
关键词
canopy tomography; canopy reconstruction; computer imaging; gas exchange; global radiation; image processing; light scanner; remote sensing;
D O I
10.1046/j.1365-3040.2000.00600.x
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
Monitoring the light-shadow windows of a tree via a grid system on the ground,vas performed on sunny summer days at high spatial resolution using a custom-built, inexpensive scanner, The measurements were taken with two goals: (1) to quickly and remotely quantify the overall, short-wave solar radiation (300-1100 mn) intercepted by the tree canopy, and (2) to yield such crown geometric: traits as shape, size anti the number of theoretical canopy leaf layers (leaf layer index, LLI) in relation to the section orthogonal to sunbeam direction (sun window). The ground readings at cad measurement over the day were used to project a digitized shadow image. Image processing was applied and the intercepted radiation was calculated as the difference from the corresponding incoming radiation above the canopy. Tree-crown size and shape were profiled via computer imaging by analysing the different shadow images acquired at the various solar positions during the day. It is notable that these combined images yielded the crown features without having to parameterize such canopy characteristics as foliage Extension and spatial distribution.
引用
收藏
页码:783 / 796
页数:14
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