Russ: There are several causes of sugar maple decline. Multi-year droughts are always a problem wherever they occur within the range of the species. Acid rain on certain soil types, leading to calcium deficiency can also contribute. In the north, European earthworm invasion is one of the main causes of decline. The worms make the soil more dense, warmer, drier and more nutrient poor (Phosphorous cycling is disrupted by earthworms and apparently this contributes to sugar maple decline). All of these changes in the ecosystem exacerbate the impacts of droughts, and also will reinforce the impacts of a changing climate. We have a study in review that shows a 30% decline in sugar maple ring widths due to earthworm invasion.
Sugar maple (like most tree species) has strong ecotypic differentiation by latitude, which does make it vulnerable to climate change. In other words, local populations of sugar maple cannot tolerate the range of conditions the species as a whole can withstand, so even a modest northward shift in range of the species will put all populations out of sync with the climate. I don't think sugar maple is going to go extinct, but its niche within its current range is likely to be reduced by all these factors. Lee [email protected] wrote: > ENTS: > > I'm not certain about the pending extinction of sugar maple. It is an > extremely common tree in areas far south of New England and most > generally the trees appear to be healthy. Because we are closer to > the sources of acid deposition and pollution from coal fired power > plants that are causing great harm the north woods I would at least > want to consider that air pollution rather than climate change is a > major factor in northern sugar maple decline. > > Russ > > ------------------------------------------------------------------------ > Feeling the pinch at the grocery store? Make dinner for $10 or less > <http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001>. > > --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
