Leaf area density
Computes a leaf area density profile based on the method of Bouvier et al. (see reference)
LAD(z, dz = 1, k = 0.5, z0 = 2)
z |
vector of positive z coordinates |
dz |
numeric. The thickness of the layers used (height bin) |
k |
numeric. is the extinction coefficient |
z0 |
numeric. The bottom limit of the profile |
The function assesses the number of laser points that actually reached the layer z+dz and those that passed through the layer [z, z+dz] (see gap_fraction_profile). Then it computes the log of this quantity and divides it by the extinction coefficient k as described in Bouvier et al. By definition the layer 0 will always return infinity because no returns pass through the ground. Therefore, the layer 0 is removed from the returned results.
A data.frame containing the bin elevations (z) and leaf area density for each bin (lad)
Bouvier, M., Durrieu, S., Fournier, R. a, & Renaud, J. (2015). Generalizing predictive models of forest inventory attributes using an area-based approach with airborne las data. Remote Sensing of Environment, 156, 322-334. http://doi.org/10.1016/j.rse.2014.10.004
z <- c(rnorm(1e4, 25, 6), rgamma(1e3, 1, 8)*6, rgamma(5e2, 5,5)*10) z <- z[z<45 & z>0] lad <- LAD(z) plot(lad, type="l", xlab="Elevation", ylab="Leaf area density")
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