Ed- I don't know if I fully grasped what you were saying, but I tend to agree with you up to a point. There are a few papers out on what I'd refer to as 'gradient analysis' where any given sample of a population is related to its range, or extent. It is generally assumed that as the populations sampled get closer to the edge of the range, the more sensitive they will be to external changes in such environmental gradients as local/regional warming trends and local/regional moisture regimes. That said, if the sub-populations do indeed have broader, more diverse genetics, and survive, that would be great, and they would be a great boon to silviculturists facing local/regional climate change. If they don't, then it's back to Mike's approach...nothing lost. -DOn
From: [email protected] To: [email protected] Subject: [ENTS] Re: Birds are Moving North Too Date: Tue, 10 Feb 2009 15:43:39 -0500 Birds are Moving North Too Mike and Don, I recognize that some trees have a wider geographical distribution than others that this represents a greater tolerance of environmental conditions for them as a species, but I am unsure if that directly corresponds to an individual of that species or a particular sub-population of that species being more tolerant than others in a particular area. One proposition is not the logical extension of the other. So managing to promote the increase of the numbers of these trees that are more tolerant of change as a species, may not really accomplish anything if the individual trees involved are not also more tolerant of change. The questions are how much variation is there between differing populations of a species in different parts of it range, and could specimens from area of the populations range survive or flourish in the environmental conditions found in a different portion of the species range. I don't know the answer, but I can't reasonably make the jump without any other evidence, that species with a broader range are made up of individual trees or subpopulations that are more tolerant of changing conditions. Ed ----- Original Message ----- From: DON BERTOLETTE To: [email protected] Sent: Tuesday, February 10, 2009 2:35 PM Subject: [ENTS] Re: Birds are Moving North Too Mike- True words! -Don From: [email protected] To: [email protected] Subject: [ENTS] Birds are Moving North Too Date: Tue, 10 Feb 2009 06:01:37 -0500 See http://www.boston.com/news/science/articles/2009/02/10/amid_warming_birds_shift_north/ Birds as well as trees and forests will slowly adapt to a warming planet or a cooling one too if that’s the case. For us foresters, it makes sense to promote those mid tolerant to tolerant species that naturally tend to become dominants and codominants with a wide range. Around my neck of the woods that would be mostly red oak and white pine. We can make forests more adaptable to climate change by using the appropriate silviculture to increase the proportion of these more adaptable species while also trying to keep our forests as diverse as possible. Man will adapt too; we always have. Mike _________________________________________________________________ Windows Live™: E-mail. Chat. Share. Get more ways to connect. http://windowslive.com/howitworks?ocid=TXT_TAGLM_WL_t2_allup_howitworks_022009 --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org You are subscribed to the Google Groups "ENTSTrees" group. To post to this group, send email to [email protected] To unsubscribe send email to [email protected] For more options, visit this group at http://groups.google.com/group/entstrees?hl=en -~----------~----~----~----~------~----~------~--~---
