Culvenor Darius S, Newnham Glenn J, Mellor Andrew, Sims Neil C, Haywood Andrew
CSIRO Land & Water, Private Bag 10, Clayton South, VIC 3169, Australia.
Victorian Department of Environment and Primary Industries, 8 Nicholson Street, East Melbourne, VIC 3002, Australia.
Sensors (Basel). 2014 Aug 14;14(8):14994-5008. doi: 10.3390/s140814994.
An automated laser rangefinding instrument was developed to characterize overstorey and understorey vegetation dynamics over time. Design criteria were based on information needs within the statewide forest monitoring program in Victoria, Australia. The ground-based monitoring instrument captures the key vegetation structural information needed to overcome ambiguity in the estimation of forest Leaf Area Index (LAI) from satellite sensors. The scanning lidar instrument was developed primarily from low cost, commercially accessible components. While the 635 nm wavelength lidar is not ideally suited to vegetation studies, there was an acceptable trade-off between cost and performance. Tests demonstrated reliable range estimates to live foliage up to a distance of 60 m during night-time operation. Given the instrument's scan angle of 57.5 degrees zenith, the instrument is an effective tool for monitoring LAI in forest canopies up to a height of 30 m. An 18 month field trial of three co-located instruments showed consistent seasonal trends and mean LAI of between 1.32 to 1.56 and a temporal LAI variation of 8 to 17% relative to the mean.
开发了一种自动激光测距仪，用于表征上层和下层植被随时间的动态变化。设计标准基于澳大利亚维多利亚州全州森林监测计划的信息需求。这种地面监测仪器获取了关键的植被结构信息，有助于克服利用卫星传感器估算森林叶面积指数（LAI）时的模糊性。该扫描激光雷达仪器主要由低成本、商业上可获取的组件开发而成。虽然635纳米波长的激光雷达并非理想地适用于植被研究，但在成本和性能之间存在可接受的权衡。测试表明，在夜间运行期间，对距离达60米的活树叶的距离估计可靠。鉴于该仪器的天顶角扫描角度为57.5度，它是监测高度达30米的森林冠层中LAI的有效工具。对三个共置仪器进行的为期18个月的野外试验显示出一致的季节趋势，平均LAI在1.32至1.56之间，相对于平均值的LAI时间变化为8%至17%。
