I wonder whether the unexpected pattern seen in the oaks around DC this
year is due to factors which can complicate the masting pattern.
A few years ago I co-authored a paper using time series of masting in
relation to climate records (G. Piovesan & J.M. Adams in Ecological
Research).
My recollection of the work is getting hazy now a few years after we
published it - and I am too lazy to look up the paper again right now -
but I think that the pattern we found with beech (Fagus) across Europe and
in North America was that the likelihood of masting was significantly
increased if a wet summer occurred during two years BEFORE the mast crop
(the year before flower primordia formed)... this suggests that a build-up
of carbohydrate in the trees predisposes them to masting if the necessary
drought trigger is present the next summer. So a run of moderately dry
years leading up to a potential drought trigger year could suppress
masting.
Also, if masting had already occurred the previous year or two - even with
the 'correct' drought trigger present - the masting would fail to occur.
Presumably, the trees were exhausted of their carbohydrate or nutrient
supply and unable to produce a seed crop.
Why is this relevant to the present topic on oaks? A drought year may not
predictably result in masting during the year when the acorns form. I
wonder then if what happened with the oaks around DC this year was due to
one of these fairly predictable complications to the pattern.
Jonathan Adams
>>
>> A front-page article in today's Washington Post
>> http://www.washingtonpost.com/wp-dyn/content/article/2008/11/29/AR200811
>> 2902045.html?hpid=topnews
>> describes the failure of the acorn mast this year over a large area
>> around Washington, D.C. Also hickory nuts. It should have been
>> (based on historical patterns) a good year for the oaks. Was there a
>> similar failure in other parts of the US (or elsewhere)?
>>
>> David Inouye
>>
>
>
>
> --
> James Crants, PhD
> Scientist, University of Minnesota
> Agronomy and Plant Genetics
> Cell: (734) 474-7478
>
