Long Term Forest Monitoring Lee Frelich
July 23, 2009


This website has a story from the BBC about a large plot of 25 hectares
(61.75 acres, 30,000 trees) Yosemite National Park where every tree > 1
cm in diameter will be mapped to monitor tree mortality and forest
change: http://www.forestrycenter.org/headlines.cfm?RefID=106485

This joins a number of other such large mapped plots including Barro
Colorado Island, Panama, and the ones I helped set up and am now
monitoring in Sylvania Wilderness, Upper Michigan. We set up 4 plots
there during 1988 in hemlock and sugar maple forests that have never
been logged that total 27 hectares (66.7 acres, also about 30,000
trees). We recently resurveyed them and will have several studies to
publish in the next year regarding forest change since 1988. Basically,
hemlock and yellow birch have not reproduced at all during the census
period, and probably not since the 1940s. Sugar maple is taking over in
the smaller size classes, even though there are also a lot fewer young
sugar maples than there were in the 1980s. The overall density is going
down. Excessive deer grazing and increasing drought frequency are the
likely causes. Earthworms have not yet invaded these study plots, so we
can't blame the lack of reproduction on them, although their invasion
front is nearby and will go through the plots soon.


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