Thursday, December 12, 2013

Wildlife Travel Corridors

According to Mike Parker, a wildlife biologist, something magical happens when a wildlife corridor is more than 60 feet (20 meters) wide.

Large animals feel more secure traveling along them, especially as the corridor matures and develops more vertical structure.  That is, dense, brushy edges with taller trees and more openness through the center.

Smaller animals have greater nesting success in the wider corridors as well.  A predator can harvest a narrow corridor as efficiently as you can select a package of bacon at Krogers.  The predator has no trouble finding the nest because it only has to search in one dimension.  The +60' wide corridor with vertical structure is baffling to predators.  A raccoon or possum might smell a bird nest, but dang, it is a lot of work to find it.

So, how can chestnuts and oaks be integrated into a wildlife corridor?

It is convenient to divide oaks and chestnuts into two categories.  Lets call them "orchard types" and "timber types".  A cross-section through a wildlife corridor might look like the graphic below.  S=Shrub, O=Orchard type tree, T=Timber type tree.  The number represent the number of feet between rows within the corridor.  Distance between rows is very flexible and depends, in part, on climate and soil moisture issues.

5'-S-5'-O-10'-T-20'-T-10'-O-5'-S-5'    Note that this creates a "mounded" appearance in cross-section.

I can only speak for Eaton Rapids, Michigan.  Shrubs are sometimes omitted.  Sometimes they are autumn olive, brambles, filberts, pawpaws or dogwood.
  • Orchard trees I have used include Chinese Chestnuts (C. mollisima) and Sawtooth Oak (Q. acutissima).  I have also seen some Gambel Oak (Q. gambelli)  that would work great in this application. Other, non oak/chestnut trees include apple, pear, American plum, persimmon and mulberry.
  • Timber trees include Sawtooth Oak (Q. acutissima), Burr Oak(Q. macrocarpa), Swamp White Oak(Q. bicolor), English Oak(Q. robar), Hybrid Chestnuts (with American or European somewhere in their ancestry).  I also sprinkle in Black Locust (Robinia psuedoacacia) for nitrogen fixing capability and to provide "sacrifice" trees to open up canopy as the trees size up.

Note to readers:

Writing can be very intimidating.  One of my goals is to "lower the bar" for writing...a bit like watching Uncle Billy water ski.  Watching somebody else flail away, and seeing that they are having a good time while flailing will make it easier (I hope) for others to contribute.

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