Monday, October 15, 2007

Squirrels fallen on hard times

Last spring, after the oaks and the forest understory had flowered, Missouri froze. A hard, killing frost reduced the spring woods to crinkly black leaves and desiccated flowers. Foresters speculated about the impacts such a late freeze would have on acorn production this fall. I didn't think we'd see a single white oak acorn, personally. My sister agency released the 2007 Mast Report last week and in it, they announced that white oak acorn production is down 58.5%. Even though their Mast Report only covered the Ozarks and other significantly forested areas (which leaves out southeast Missouri), I'm finding the same low numbers of white oak acorns in my small patch of woods as the rest of the state.

Red oak acorns, on the other hand, are only down 8% from last year's crop. White oak acorns are formed the same year as the flowers are formed. Red oaks, the group that includes scarlet oaks, Shumard's, and pins, take two years to produce acorns. This year's production is based on last year's flowering event. Of course, next year will be a bad one for red oak acorns since this year's flowers were killed by the frost.

As a courtesy to hunters interested in mast-eating mammals like squirrels and deer, foresters in my sister agency have produced Mast Reports since 1960. Foresters report that this year's production is the lowest in recorded history. Squirrels will be impacted more dramatically than deer. Squirrels distinguish between white and red oak acorns; red oak acorns are higher in fat, but also high in the distasteful tannins. White oak acorns have less fat and also fewer tannins.

While squirrels prefer fatty red oak acorns, if the white oak acorns are more abundant, they will eat more of them just after acorn drop. White oaks send out taproots days and weeks after they fall, while red oaks sprout the following spring. Since the tannins in white oak acorns are concentrated in the taproot, squirrels tend to eat them first, and store red oak acorns for the winter. Recent research has shown that squirrels will only eat the top part of the red oak acorn (about 60% of it) to avoid the concentrated tannins at the embyronic end. Even though squirrels eat the bulk of an acorn, the remaining part can still produce a tree. Estimates suggest that 74% of all buried acorns are never found again.

With white oak acorn populations impacted by the frost, squirrels will be forced to eat and store red oak acorns if they plan on eating this winter. If you live in an area impacted by the Easter freeze, I recommend stocking up on peanuts, suet and corn for your squirrel feeders. This winter, you should do it not just for selfish viewing reasons, but because they actually need the help.

1 comment:

Anonymous said...

I cannot believe all this interesting,enlightening info about the acorn population.amazing!