Leaf Area Index Data, South-East Queensland Peri-urban SuperSite, Samford, Core 1 ha, 2014

Canopy leaf area index data were collected by David Tucker using digital cover photography (DCP) for the South East Queensland Peri-urban SuperSite Samford. Nine transects were established within the one hectare plot. A Nikon D5200 single-lens reflex camera and AF-S DX Nikkor 18-55 mmf/3.5-5.6G VR lens was used for recording all images. Camera settings Included ISO200, f8.0, exposure -1.0 and RAW format.

Leaf area index (LAI) can be defined as the total one sided area of leaf tissue per unit area of ground and is a key derived parameter that is associated with water and light interception, radiation transfer, water and carbon exchange (Bréda, 2003). Canopy cover can be defined as the fraction of ground shaded by the vertical projection of tree crowns (Walker et al. 1981). These measures may be used as proxies for actual canopy leaf area. Leaf area index is the preferred measure of cover for vegetation and as a key variable used in total biomass estimation and in carbon cycling prediction models. Indirect measures of LAI include digital photographic methods using flat or hemispherical images, referred to respectively as DCP (digital cover photography) and DHP (digital hemispheric photography).

LAI measurements are carried out at each SuperSite using the most appropriate method for the vegetation type present. Digital Cover Photography (DCP) is recommended for medium stature (10-40 m) vegetation with simple structure. DCP was originally developed for sparse to moderately dense broadleaf forest and has also been tested in sparse savanna woodland. DCP is recommended for these vegetation types and has also been suggested for more dense forests (Pekin and MacFarlane 2009).

Digital Hemispheric Photography (DHP) is recommended for short vegetation (4-8 m) e.g. low banksia woodland, complex (multi strata) and tall vegetation (> 40+ m) using images taken 20 m apart (MacFarlane et al. 2007).

冠层叶面积指数（Canopy Leaf Area Index, LAI）数据由戴维·塔克（David Tucker）采用数字覆盖摄影（Digital Cover Photography, DCP）方法，于昆士兰州东南部城郊超级样地萨姆福德（South East Queensland Peri-urban SuperSite Samford）采集。该1公顷样地内共设置9条样带，所有影像均通过尼康D5200单反相机（Nikon D5200 single-lens reflex camera）搭配AF-S DX尼克尔18-55mm f/3.5-5.6G VR镜头拍摄，相机参数设置为ISO200、光圈f/8.0、曝光补偿-1.0以及RAW格式。

叶面积指数（LAI）指单位地面面积上植物叶片组织的单侧总面积，是与水分和光能截获、辐射传输、水碳交换密切相关的关键衍生参数（Bréda, 2003）。冠层覆盖度定义为树冠垂直投影所遮蔽的地面比例（Walker et al., 1981），二者均可作为实际冠层叶面积的替代表征。叶面积指数是植被覆盖度评估的首选指标，同时也是总生物量估算及碳循环预测模型中的核心变量。叶面积指数的间接测量方法包括采用平面或半球面影像的数字摄影技术，分别对应数字覆盖摄影（DCP）与数字半球摄影（Digital Hemispheric Photography, DHP）。

各超级样地的LAI测量会根据所在地植被类型选用最适配的方法。数字覆盖摄影（DCP）适用于结构简单的中等株高（10~40米）植被。该方法最初为稀疏至中等密度的阔叶林开发，同时也在稀树草原林地中开展过测试，除上述植被类型外，也被推荐用于更为茂密的森林（Pekin & MacFarlane, 2009）。

数字半球摄影（DHP）则适用于低矮植被（4~8米，如低矮班克木林地）、结构复杂（多层冠层）植被以及高度超过40米的高大植被，影像采集间距设定为20米（MacFarlane et al., 2007）。