Tom's Blog

Tuesday, November 18, 2014

White-tailed Deer: Another reason to do an oak woods burn!

A neighbor scouting for deer in the North-facing oak woods that we had recently burned spotted nine female deer with their heads down, feeding. Eating on what? Acorns, of course. Everyone knows that acorns (hard mast in hunter terminology) are a favorite deer food: “the ecological equivalent of manna from heaven”. But you don’t usually see that many in a woods all together.

What is unusual here?
  • As I posted last month, this is a big mast year for red oaks, at least at Pleasant Valley Conservancy. 
  • The North Woods at Pleasant Valley consists primarily of red oaks, so right now the forest floor is full of acorns.
  • Two weeks ago we burned the whole North Woods.
  • Burning does two things for the acorns
    • It gets rid of the leaves so the ground is bare and the acorns are visible
    • The heat roasts the acorns and makes them more palatable.
  • Deer love acorns

Acorns in the red oak group taste bitter because of their high tannin content. One way to get rid of the tannins apparently is by roasting. “Acorns roasting on the open fire”?

My neighbor also managed to attract two fawns to him by a few of the right type of “clucks”. Pretty tame!

There is a question about the effect of fire on acorn viability. According to some U.S. Forest Service work, temperatures where oak leaves are burning can range from <79 to="">371 C. Viability tests on acorns collected after a prescribed burn showed that “patchy, low-intensity dormant season burns in oak forests reduced the viability of red oak acorns located on the leaf litter surface, but did not generally affect acorns in the duff or mineral soil.” Greenberg et al. Acorn viability following prescribed fire in upland hardwood forests. Forest Ecology and Management 275 (2012) 79-86.

In a good mast year lots more acorns are on the ground than needed for oak reproduction. The benefits of fire for oak growth must far outweigh any harmful effects.

It may still be possible to see a forest floor full of acorns. Unit 11B, the savanna just south of the upper road, has mostly red oaks, and a few weeks ago the ground was full of acorns. You should hear the ground crunch under your feet as you walk through these woods. Unless the squirrels have already packed them all away!


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