Wednesday, January 09, 2013

Winter walk in chert woods

 It was a breezy but quiet 45 degree morning earlier this week when I set out to the woods for a round of winter birding. Highlights of the day include the 14 cedar waxwings sitting still on a gnarly old post oak and the two hermit thrushes that we always see in the same area, year after year for nine years. The diversity of the chert woodlands and the dolomite glades is evident even in winter when the notable stalks of goldenrods and asters and the showy Sporobolus clandestinus remain erect even after a four inch snow event. Winter botany is becoming easier the longer I stay in Missouri.

There have been discussions in recent years from folks unaware of exactly how natural communities exist on the landscape. I've been privy to one conversation with foresters who told me that if we cut trees on a north and east facing slope, the same plant community that exists on a southwest facing slope will occur. Visiting my favorite burned woods this week, I witnessed the effects of those north facing exposures with their closed canopy (though frequently burned) structure. The December 31 snow event is a thing of the past here, except for on the north slopes. Slope, aspect, topography all play roles in the establishment of distinct natural communities. We'll never see a warm season grass-widely spaced post oak-dominated dry chert woods on those north slopes. Some of the dry woodland elements are there, but they're structurally distinct from the harsh environments of the southwest slopes--the trees are closer together, more erect, and there are species differentiations, as well. Fire behaves differently on north slopes compared to south slopes, and since fire is responsible for shaping natural communities, it only makes sense that north and east slopes will have different character than exposed southwest slopes...

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