![\"canopyheight\"](\"http:\/\/generic.wordpress.soton.ac.uk\/tda\/wp-content\/uploads\/sites\/91\/2016\/02\/canopyheight.jpeg\")
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This LiDAR image shows a canopy height profile across a narrow transect through a 500-year-old-growth Douglas fir forest. Each dot represents a return of a laser pulse. The colours indicate height in meters above the ground. This structural variability creates a wide range of habitats for different wildlife and plant species. (Image courtesy of Tom Spies and Keith Olsen, Oregon State University College of Forestry)<\/p>\n
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Reflection<\/h3>\nThe figure below shows LIDAR points for\u00a0two different vegetation types and different growth stages in different colours. Can you first identify the vegetation types and then the colour of LIDAR point related to growth stage?<\/p>\n
![\"leaf_off_lefon\"](\"http:\/\/generic.wordpress.soton.ac.uk\/tda\/wp-content\/uploads\/sites\/91\/2016\/02\/leaf_off_lefon.gif\")
<\/a><\/p>\nThe figure above shows cross section of LIDAR data through a single deciduous tree (A) and coniferous tree (B) including ground returns. The green dots represent leaf-on returns and the brown dots represent leaf-off returns. Note that: for deciduous trees there is a higher difference between these points compared to coniferous tree.<\/p>\n<\/div><\/div>
Incorrect<\/span><\/div><\/div><\/div><\/div>\n
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What can be measured?<\/h3>\n
Forest can be characterised by the attributes of a single or a group of tress. Basic attributes for a tree includes canopy height, diameter at breast height (dbh), crown diameter, basal area ( cross section at dbh), volume, biomass and leaf area Index. These are summarised in table below (Dubayah and Drake, 2000).\u00a0Some of these can be directly measured from the LiDAR data where as others need to be estimated through statistics or modelling. These information are being increasingly used\u00a0 by the United states forest service in assessing forest fire fuel and habitat.<\/p>\n
<\/p>\n
The figure below shows LIDAR points for\u00a0two different vegetation types and different growth stages in different colours. Can you first identify the vegetation types and then the colour of LIDAR point related to growth stage?<\/p>\n
The figure above shows cross section of LIDAR data through a single deciduous tree (A) and coniferous tree (B) including ground returns. The green dots represent leaf-on returns and the brown dots represent leaf-off returns. Note that: for deciduous trees there is a higher difference between these points compared to coniferous tree.<\/p>\n<\/div><\/div> <\/p>\n Forest can be characterised by the attributes of a single or a group of tress. Basic attributes for a tree includes canopy height, diameter at breast height (dbh), crown diameter, basal area ( cross section at dbh), volume, biomass and leaf area Index. These are summarised in table below (Dubayah and Drake, 2000).\u00a0Some of these can be directly measured from the LiDAR data where as others need to be estimated through statistics or modelling. These information are being increasingly used\u00a0 by the United states forest service in assessing forest fire fuel and habitat.<\/p>\n <\/p>\n<\/a><\/p>\n
\nWhat can be measured?<\/h3>\n