Monday, March 17, 2014

East Field

Fields at Blue Jay Barrens are mowed to achieve certain management objectives.  The mowing last fall was the second in a series of activities intended to clear the field of unwanted trees and shrubs.  I am currently evaluating the effectiveness of the first two steps and estimating the time required to complete the next step. 

Sometime later in the spring I’ll be cutting and stump treating young Red Maple and Ash that are rapidly infiltrating some of the wetter areas of the field.

The prairie grasses grew very well last year and left considerable dead material on the ground after the mower passed.  By next fall, all of this dead material will have decomposed.  The nutrients and organic matter will cycle back into the soil.  The disappearance of this material is an indicator that the soil ecosystem is healthy and functioning as it should.

Small cedars were cut from this field prior to the fall mowing.  Most of those cedars were in the one to two foot height range, but I cut every little cedar that I could find.  While mowing, I discovered and cut more small cedars that had been missed earlier.  The heavy snows this winter managed to flatten the grass and allow more small cedars to become visible.  Now I’m cutting very small cedars that I was unable to see earlier.  This field will be as cedar free as I’m able to make it.

There are some trees and shrubs that are left undisturbed.  Prairie Rose, Rosa setigera, is untouched with the hope that it will produce a nice floral display next summer.  I believe that I’ve finally reached the point where mature native roses outnumber the invasive non-native Multiflora Rose.

It’s plants like this Shrubby St. Johnswort, Hypericum prolificum, that make mowing difficult.  A watchful eye is required to spot small plants hidden in the grass.  If it weren’t for the dark colored seed capsules, I would not see this plant before the mower ran it over.  I do manage to run over a few desirable woodies, so it’s fortunate that most woody plants will grow back if mowed off.  It’s the sound the mower makes when cutting something more substantial than grass that alerts me to the fact that I’ve shortened something meant to be left tall.

Deerberry, Vaccinium stamineum, is fairly easy to see.  Besides watching in front of the mower, I also keep a watch to the side that has yet to be cut.  When I spot a plant that should be saved, I mark it with a blue flag that is easy to see the next time I pass that way.

Larger trees and shrubs are found primarily around the outer margins of the field.

Flowering Dogwood, Cornus florida, which used to be a common woodland understory plant, lost their battle to disease and survived as only a few scattered individuals growing in the open field.  My management in favor of this species has resulted in a healthy population of mature Dogwoods.  Many have grown into small trees that produce a showy display and a hefty crop of berries.

Many of the open field shrubs host bird nests.  This nest is looking rather weathered, but I’m guessing from the thistle down that it housed a family of Goldfinches.

Oaks are the second most abundant type of woody plant left in the fields.  Many of the prairie species in the field have relationships with oaks.  I thought it desirable to give some space to the oaks while I learned about these relationships.  The oaks can always be cut out later if that turns out to be the best management option.

One positive association of which I’m aware is that between the oaks, Allegheny Mound Ants and Edwards’ Hairstreak Butterflies.  I’ve written before about this relationship.  Searching the list of blog subjects in the right hand column will provide you with more details.  Without oaks and ant hills, you cannot have the butterflies.  The butterflies were first seen in this field ten years ago and have been increasing in number.  Apparently the decision to grow oaks has had some beneficial effects.

In some places the tree canopy is blocking enough sunlight to change the composition of the ground cover.  These changes are being monitored and a future decision may have to be made about the removal of some of the larger trees. 

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