> >there seemed to be a growth response that initially favoured the closer >spacings. This changed with time and the optimum spacing seemed to move from >the densest to less dense stockings as the years went by. Eventually the >densest stockings exhibited less height (and diameter) growth. We >hypothesised that we were witnessing a shelter effect that at first favoured >the densest stockings, then a competition effect as the trees grew to fully >occupy the space then compete for resources. > For what its worth, the same thing happenned in an annually-measured loblolly pine spacing study in South Carolina that included very close spacings; i.e. close spacings were taller early on. Presumed by us to be the "shelter effect" that Ryde mentions. Also, it is worth mentioning that the U.S. Pacific Northwest has been all "abuzz" for a few years now about such an effect in Douglas-fir spacing trials, only it shows up in both diameter and height (greater in closer spacings) and appears well any self-sheltering could occur. Something more "mysterious" is going on there. wade harrison summerville sc 72053.3000@compuserve.com
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