I have recently experimented with the automated delineation of trees from high resolution imagery and also from Lidar. Since I have also derived the approximate height of each point from the LiDAR derived height layer, I would now like to get the inter-tree distance between each tree and its nearest five neighbors. My intent is to then use this as a tree specific measure of density/spacing to derive a more accurate estimate of each tree's diameter. Since there are from 500 - 5000 stems per hectare and I am dealing with approximately 70,000 hectares, the processing may be significant. While I have some ideas on how this might be accomplished, I don't have a super-computer at my disposal to complete all of the calculations.
If anyone has any ideas on an efficient process for making these calculations, your input would be greatly appreciated.