307 Relative crown distance
Relative crown distance is crown diameter related distance to surrounding trees in main directions (CDRD_N).
The relative distance between trees explains to a high degree the variability of characteristic defoliation data of deciduous trees.
Scores are given for each perpendicular direction.
It is recommended to start with the tree standing closest to the sample tree in a clockwise procedure.
Dead trees are taken into account, as long as they are in the crown condition sample.
Calculation: (Score1 + Score2 + Score3 + Score4) / 4 = CDRD_N
Crown diameter is a relative measure used to analyse crown stand structure in four perpendicular directions.
Score values are to be averaged.
If detailed stand structure information including crown projection maps of single trees is available, crown diameter related distance of sample trees can be calculated from this information.