This module is connected to SamsaraLight library. It loads detailed inventory files, computes the light intercepted by trees and the light transmitted to ground cells or virtual sensors. This model is particularly useful to perform sensitivity analysis of SamsaraLight model and to analyze the effect of partial harvest on the distribution of light among the trees and regeneration. Functions are also available to compare light prediction versus light measures.

• The angle between North direction and x axis clockwise must be 0, 90, 180, or 270.
• The angle between y axis and x axis clockwise must be 90.
• The crown radius must be defined along the cardinal directions (N,E,S,W).

If your plot was mapped with a different coordinate system, then you must transform yourself the coordinates of trees and plot extents. In this latter case, I recommend to set samsaraLightLoader to use a north-to-X-angle of 90°, i.e. Y axis corresponds to North direction. Additionally, I recommend adding a virtual buffer stand (with random virtual trees) in the corner of the rectangular Capsis plot where you do not have any information.

Normally, an up-to-date example of inventory file is available in the capsis/data/samsaralightloader directory. the good spelling of keywords is very important and case sensitive. The order of the information included in this file is equally very important and must be as described below.

• plotName : the name of your plot (not really important)
• date : the date of your inventory (not really important)
• cellWidth : the width of the cell. Smaller the cells, longer is the simulation
• plotXMin, plotXMax, plotYMin, plotXMin : The extent of the rectangular plot
• plotSlope : The angle, in degree, of the ground slope to the horizontal
• plotAspect : The angle, in degree, from north direction to the direction looking downwards the slope, clockwise.
• plotNorthToXAngle : The angle, in degree, from north direction to x axis, clockwise. Either 0, 90, 180, or 270.
• plotLattitude : the lattitude of your site
• plotLongitude : the longitude of your site
• addVirtualBufferStand : In the case of the inventory zone is smaller than the capsis plot defined by the above extent, setting addVirtualBufferStand to true add virtual trees outside of the inventory zone. (optional)

A table with 3 columns:

• species code : a unique code for each species. The ones use in the tree records.
• species name : a name for each species (to be displayed in charts)
• species color : the RGB color of crown in stand visualizations.

A table with two columns: x and y values of the vertex of the inventory zone. All vertex must be given in a clockwise order.

A table with 7 columns:

• sensor id
• x
• y
• h : height of the sensor above ground
• PACL total
• PACL diffuse
• PACL direct

To be completed…

A table with 14 columns:

• tree id
• species code
• x coordinate in m
• y coordinate in m
• tree diameter at 1.3m in cm
• tree height in m
• height of the base of tree crown in m
• height of the maximum crown extension
• crown radius in North direction in m and > 0
• crown radius in East direction in m and > 0
• crown radius in South direction in m and > 0
• crown radius in West direction in m and > 0
• crown openness, a value between 0 and 1
• crown leaf area density in m²/m³

see SamsaraLight documentation.

TO DO

download a capsis release with samsaraLightLoader

Ligot, G., Balandier, P., Courbaud, B., Claessens, H., 2014. Forest radiative transfer models: which approach for which application? Can. J. For. Res. 44:385-397. link

Ligot, G., Balandier, P., Courbaud, B., Jonard, M., Kneeshaw, D., Claessens, H, 2014. Managing understory light to maintain a mixture of species with different shade tolerance. For. Ecol. Manage. 327:189-200.

Gauthier Ligot
Université de Liège Gembloux Agro-Bio Tech, Gembloux, Belgium