Testing the Application of Terrestrial Laser Scanning to Measure Forest Canopy Gap Fraction
Testing the Application of Terrestrial Laser Scanning to Measure Forest Canopy Gap Fraction
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DOI：
10.3390/rs5063037
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发表时间：
2013-06
期刊：
影响因子：
--
通讯作者：
F. A. Ramirez;R. Armitage;F. Danson
中科院分区：
文献类型：
--
作者：
F. A. Ramirez;R. Armitage;F. Danson
地面激光扫描仪（TLS）有可能彻底改变植被冠层三维结构的测量，以应用于生态学、水文学和气候变化。这种潜力一直是最近研究的主题，试图从TLS数据测量森林生物物理变量，并与半球摄影的二维数据进行比较。本研究提出了一个系统的比较森林冠层空隙率估计来自TLS测量和半球摄影。研究中使用的TLS数据集于2008年4月至2009年3月在英国柴郡的德拉米尔森林获得。来自TLS数据的冠层空隙率估计值的分析突出了测量结果的重复性和一致性，与那些从重合的半球照片。比较还表明，仅考虑TLS数据集中登记的命中和未命中数量计算的估计值始终低于半球照片的估计值。为了检验这种差异，研究了TLS记录的强度值中可用的潜在信息，并提出了一种新的估计林隙分数的方法。新方法产生的间隙分数更接近半球摄影估计的值，但研究也强调了单次返回TLS数据在此应用中的局限性。
Terrestrial laser scanners (TLS) have the potential to revolutionise measurement of the three-dimensional structure of vegetation canopies for applications in ecology, hydrology and climate change. This potential has been the subject of recent research that has attempted to measure forest biophysical variables from TLS data, and make comparisons with two-dimensional data from hemispherical photography. This research presents a systematic comparison between forest canopy gap fraction estimates derived from TLS measurements and hemispherical photography. The TLS datasets used in the research were obtained between April 2008 and March 2009 at Delamere Forest, Cheshire, UK. The analysis of canopy gap fraction estimates derived from TLS data highlighted the repeatability and consistency of the measurements in comparison with those from coincident hemispherical photographs. The comparison also showed that estimates computed considering only the number of hits and misses registered in the TLS datasets were consistently lower than those estimated from hemispherical photographs. To examine this difference, the potential information available in the intensity values recorded by TLS was investigated and a new method developed to estimate canopy gap fraction proposed. The new approach produced gap fractions closer to those estimated from hemispherical photography, but the research also highlighted the limitations of single return TLS data for this application.