does anyone have information on the topic of tree stand density as related to the probability of future tree failure. I have listened to Shigo, Methaney and Clark, etc., but am curious as to "micro-climate" and density. Thanks

Reply to post by Bill Cassel, on June 26, 1998 at 12:54:45:

No specific literature comes to mind. I think the most important characteristics to look for in stand-grown trees is live crown ratio and height/diameter ratio. In general, we consider a 30% LCR a minimum for tree stability when the stand is open (that is, for Pacific Coast conifers). I would expect that the greater the stand density, the smaller the LCR and the less stable the tree.

Reply to post by Nelda Matheny, on June 26, 1998 at 12:54:45:

I agree with Nelda, but would add that relative canopy position is also very important. Dominant conifers will typically be more stable than codominants, which are themselves more stable than subdominants, which are all more stable than suppressed trees. I see a lot of sites where people think they can save the smaller (suppressed) trees and remove the overstorey. Generally the suppresed trees have very small root systems and are very unstable once they are beyond the "pole" stage of development. While I do not recall much forestry literature on the edge failure, the nature of canopy position, and stand dynamics in general is relevant and there is a considerable literature on that, mainly from the biomass production viewpoint, and how the forest manager should thin out a stand to cull the weak trees and encourage the strong ones. You can translate that type of information fairly readily into stand and individual tree stability. The LCR will be a reflection of canopy position to some extent, but within any one stand, there will be microsite variations that can alter stability issues. The other factor to consider will be soil types and soil hydrology. Creating a new edge can radically alter soil hydrology depending on soil type, slope, aspect, and the nature of the disturbance.

Julian Dunster

Reply to post by Bill Cassel, on June 26, 1998 at 12:54:45:

Have you posed this query in either the forestry or agroforestry newsgroups?


jps