Weird question on phenology

Richard Winder rwinder at PFC.Forestry.CA
Wed Oct 5 11:56:36 EST 1994


In article <36q9ir$868 at balsam.unca.edu>, STRAUSS at uncavx.unca.edu 
(Robert Strauss) writes:
>Please forgive me if this is not appropriate to this group, though I think I
>would get more erudite thoughts here, than in rec.gardens.
>
>In Asheville, this year, the trees are coloring very early. In fact, the Maples
>(Sugar maples) began earlier than in the north (i.e., NY State). I had always
>assumed this would be related to weather conditions. I.e., Asheville (NC) is
>warmer than further north. At least then interior north. This year, however, I
>began wondering. Is it possible that plants have a "length of season" that is
>fairly fixed? So that in NY, for example, the season might be 5.5 months, and
>here it might be 6.1 months. Season being from first leafing out until color
>comes. Thus, my idea is that this year, since we had a very early spring here,
>and did NOT have (for once!) a late frost, the season has been reached and
>plants have been green for their fixed time, so they are turning.
>
>Any ideas? I have collected observations (phenology) since 1961, though that
>was in NYC.

You might be right about there being some type of "timer" or "memory" that 
could influence dormancy- I've seen apple trees bloom very late the
year after being bitten hard by late frost.  In the Raleigh area, it is well
known that oaks will produce a heavy crop of acorns in years following drought-
it would seem that trees can "remember" seasons. However, photoperiod is a 
fairly predictable influence.  Stresses which are usually cited as offsetting 
this influence include water limitations and temperature extremes (you could 
also probably add disease and predation).  Then there is elevation- the 
spruce growing on top of Mt. Mitchell are usually found much further north- 
it is conceivable that even lower elevations of the southern Appalachians 
could get the jump on more northern lattitudes, given the right environmental 
stresses.  	-RSW


  RICHARD WINDER                    Title: Research Scientist
  Canadian Forest Service           Phone: (604) 363-0773
  Victoria, B.C.                    Internet: RWINDER at A1.PFC.Forestry.CA



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