Ray and Joe: I think I lifted the 250 year figure from the meteorological literature, so its nice to see that a meteorologist (Ray) agrees.
A direct hit by a hurricane would be necessary to level a stand of trees and set the developmental stage back to the even-aged sapling stage, and this would only occur in a small swath on the right front quadrant (probably only 20 miles wide) of an incoming hurricane, where winds reached velocities of about 100-110 mph or more. That's why the return time is 250 years. Lesser winds would spread out over a larger area each time a hurricane occurs and have a shorter return time at a given location, but their effect on the forest would be gap creating events analogous to a group selection cut, so such winds (70-90 mph) would be part of the regime that maintains a multi-aged condition over time. The furthest inland I have heard of hurricane damage completely leveling forests is about 125 miles, 75 miles inland is a more common limit for winds strong enough to level a forest, in the 100-110+ mph range (and of course elevation and aspect on which a stand of trees grows has an influence). Western MA probably doesn't get hurricane winds that strong because the eye of the storm would pass over Long Island before hitting shore in CT, and would be somewhat weakened. The derechos that we get in MN with 120 mph winds usually weaken so that maximum winds are only 70-80 mph by the time they reach western MA, so western MA is an area with a relatively mild wind climate, like cove forests of Great Smoky Mountains NP. Lee Ray Weber wrote: > The 250 year figure is based on a "direct hit", not side effects, and that > is a known meteorological number. That would bring in excess of > hurricane force > winds mostly over eastern Massachusetts, We do get some sub hurricane > force > winds at a closer frequency. It was an anomoly to have the two in 1938 > and 1955. > 1955 was more of a flooding issue. > > Ray > > > -----Original Message----- > From: "Joseph Zorzin" <[email protected]> > To: <[email protected]> > Date: Mon, 04 May 2009 10:13:56 -0400 > Subject: [ENTS] Re: Kalanu Prong, Greenbrier, TN GRSM 4-21-2009 > > > > ----- Original Message ----- > From: "Lee Frelich" <[email protected]> > To: <[email protected]> > Sent: Monday, May 04, 2009 9:05 AM > Subject: [ENTS] Re: Kalanu Prong, Greenbrier, TN GRSM 4-21-2009 > > > > > > Joe: > > > > Based on some research I did during the 1990s, for part of New > England > > and other coastal areas hit by hurricanes (perhaps every 250 > years for a > > direct hit at any given location), one would expect about 1/3 of the > > landscape to be covered with even-aged stands in various stages of > > development, about 1/3 in transition to uneven-aged condition, > and the > > remaining third old multi-aged stands, usually referred to as > old growth. > > ********** > Lee, just curious about the 250 year frequency for hurricanes, a > figure I've > heard elsewhere. How dependable is that statistic? > > And, the "hurricane zone" would include about what percentage of > all of New > England? Or, another way to ask that- it would include roughly > what distance > from the shore? > > Your breakdown into thirds seems very reasonable and without any > divine > intervention with better facts, probably the best we can have. > ********** > > > > > > For areas not in the direct path of hurricanes, such as western MA, > > where hurricane winds were not very powerful, and thunderstorm winds > > such as derechos and tornadoes were the common form of disturbance, > > probably about 10% of the stands would be even-aged, 10% in > transition, > > and 80% would be old multi-aged stands. The southern > Appalachians would > > probably have been in this category, because they are far > inland, giving > > protection from the full strength of hurricanes, but not so far > inland > > as to be in tornado alley. > > ********** > that all sounds reasonable > ********** > > > > > > Of course, using a natural heritage definition of old growth, > anything > > that had not been logged, then it would all have been old > growth. Its > > also important to note the 'even-aged' stands after natural > disturbance > > are very different in character than even-aged stands after clearcut > > like the ones that have been done recently in MA, since there is > a lot > > more coarse woody debris, and usually remnant trees of a variety of > > sizes and ages. > > ********** > Right. Do you have a rough estimate of about what percentage of > the New > England landscape was strongly influenced in structure by Native > burning? > > Joe > ********** > > > > > > > Lee > > > > Joseph Zorzin wrote: > >> Question for Bob and Will and the others. Roughly speaking, what > >> percentage of the forests of the East - if we could go back a > >> millennium- would appear to us as "old growth"?? > >> > >> Of course there have always been fires, storms, clearings for > >> villages, etc. I'm just trying to get a sense- if we could go > back and > >> wander around the forests- would they be filled with gigantic > trees, > >> thus looking very different from now, or not? > >> > >> Joe > >> > >> ----- Original Message ----- > >> *From:* [email protected] <mailto:[email protected]> > >> *To:* [email protected] > <mailto:[email protected]> > >> *Sent:* Saturday, May 02, 2009 9:11 AM > >> *Subject:* [ENTS] Re: Kalanu Prong, Greenbrier, TN GRSM > 4-21-2009 > >> > >> Will, > >> > >> A phenomenal report as usual. It would be great to have > a list > >> of all the 20-foot circumference trees in the Smokies. > Information > >> in email communications becomes too scattered. Anyway, > thanks for > >> the great reports. > >> > >> Bob > >> > >> > >> > > > > > > > > > > > --~--~---------~--~----~------------~-------~--~----~ 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] -~----------~----~----~----~------~----~------~--~---
