Follow by Email

Thursday, July 28, 2016

CONNECTICUT’S LAST VIRGIN FOREST


The tree stumps so prominent in my 1976 plot were now gone without a trace.  They were leftovers from the 1938 hurricane, which passed nearly over this low hill bordering Connecticut and Rhode Island.  Until that time, the site had been cloaked in a stand of old growth that had never been logged, although storms like the 1815 hurricane had similarly taken their toll, as evidenced by growth rings on stumps recorded by Harvard botanist Hugh Raup shortly after the 1938 storm.  These were still visible to me 38 years later.  It was the last forest in Connecticut with any claim of being virgin although, to be sure, it was one with a dynamic history of growth, disturbance and regeneration.

I first visited this site in July of 1976, when I was quantitatively analyzing Connecticut’s newly defined critical habitats.  The site had grown up to a dense, even-aged stand of young trees, most of which could trace their beginning to 1938.  During my investigation, the prevailing forest cover was of trees just under 40 years old and with an average diameter at breast height (dbh) of 18 cm.  Except- all the old trees had not been blown down.  There were still a handful of much bigger trees that had clearly started growing long before that time.  There was a monumental sassafras with a 62.3 cm dbh - two feet across- quite something for a tree that typically appears in southern New England forests as a scrawny understory tree. There was also a mammoth white oak with a dbh of 86.6 cm- approaching three feet in diameter- a black oak of 53.3 cm dbh, a red maple of 72.9 cm dbh and a ‘red’ pignut hickory of 72.9 cm dbh.

To characterize this site and to provide a baseline for future investigation, I established a 10 x 20 m plot that was clearly delineated by the presence of a massive boulder at its northeast corner (remember, these were the days before GPS).  I found 11 canopy trees of three species that had a mean diameter of 25.9 cm.  The giant sassafras was the largest of them.  Saplings included the same species found in the canopy: white oak, black oak and sassafras, although it appeared that red maple might grow in importance as a canopy tree. The site was also a very xeric one, with a shrub layer dominated by a dense stand of huckleberry. 

This brings us to today- 28 July 2016- when I again visited the site and re-surveyed my old plot, still easily distinguishable from the presence of the boulder and immense sassafras.  Over the intervening 40 years, the forest had changed, with only seven canopy trees now averaging 37.4 cm dbh being present.  One of these was indeed a red maple of 18.1 cm dbh- a 1976 understory tree that had, as predicted, invaded the canopy.  Furthermore, the old sassafras, although still an imposing presence within the plot, was recently dead, with its uppermost branches now carpeting the forest floor.  The shrub layer was still strongly dominated by huckleberry, although the tall blueberry I had identified in the plot turned out to be Vaccinium atrococcum rather than the V. corymbosum I had mistaken it for in 1976- silly me; the latter is a wetland shrub, as I knew, and this was no wetland.  The former is much more of an upland species in southern New England.

In general, the canopy of the site as a whole had greatly thinned and now resembled that of typical mature forests in the region.  Indeed, with a present prevailing canopy age of about 80 years, it should .  As I investigated the vicinity, I found a number of substantial tree specimens.  I measured 22, which had an average dbh of 62.2 cm compared with 49.9 cm dbh for 24 trees in 1976.  The largest was now an 83.9 cm dbh red maple.

I have now lived long enough to witness first hand the process of forest succession- not inferred it from forest stands of different ages, but directly observed it by examining the same plot over a very long series of years.  This raises an issue: this site, with its long and periodically catastrophic history, does indeed represent a virgin stand despite not looking terribly different than a hundred others in the vicinity.  Periodic disruption is part of the natural process that keeps this woodland in a state of more or less dynamic equilibrium.  Fortunately for those of us interested in such things, it is now owned by a land trust, so we can continue to follow its evolution for decades to come.

Robert J. Craig

No comments:

Post a Comment