Saturday, February 15, 2014

Tree Rings

Our last winter storm (Feb 12th) just brought us a bunch of snow, but no damage to trees or structures.  That was not the case for the ice storm a just over a week before (Feb. 4-5).  Besides losing power for a couple of days we lost a number of trees in the surrounding woods.  Some were standing snags, but a number were live trees.  Also, a lot of branches fell out of the White Pines. 

While beautiful, the ice from this storm stuck to the trees and caused a lot of damage.

Last spring I used available branches
 to build tomato supports.
I've just started cleaning up the mess and am imagining what can be done with all this fallen trees and branches.  I have been setting aside some of the straighter pine limbs to use as vertical supports in the vegetable garden (tepees for beans and cucumbers and trellises for tomatoes).  I am leaving the pine boughs out now in hopes that the deer will eat them, rather than go after my Rhododendrons and Yews.

The Black Cherry with its scaly bark is on the left.
On the right is the Black Locust with deeply furrowed bark.
This Locust was more than 40' tall.
The main use for the fallen trees will be as firewood.  The fallen snags could be used this year, but the live trees will need to be cut and aged for at least a season to dry out.  One of the trees that came down was a  20-30 year old black cherry easily identified by its bark, the lenticels on the branches and the unpleasant  odor where the bark had been stripped off.  I needed to do a little reading to ID the other tree.  I assumed it was one of the many red oak trees here, but the branches had thorns on them. 

Thorns on Black Locust are paired up.  
That suggested some type of locust tree.  Turns out it is a Black (aka Yellow) Locust, Robinia pseudoacacia.  The bark is deeply furrowed and the smaller branches are armed with pairs of thorns.  The 'yellow' part of the common name became evident as I was using the chain saw.  The wood chips had a definite yellow color to them.

Black Locust is considered an invasive species in New England, but here in the Mountains of Maryland we are within its native range.  The trees are subject to wind throw (as happened here) and the wood is weak and brittle.  On the plus side it is very rot resistant, so the old branches could be good supports in the garden.  As the wood burns very hot,  it will also make good firewood.

This section of the truck was growing horizontally.  Note how far off-center the growth rings are.
The wood under the greater tension is more compact (top) compared to the bottom side.

This section taken from straight portion of the truck shows even growth.

As I sawed through the twisty parts of the upper leader I noticed how the growth rings were off center.  This reminded me of a talk given at New England Grows in 2012 by E. F. Gilman from the University of Florida on Advanced Pruning Strategies.  They had done studies on how different pruning methods would affect the mechanical stress on trees.  Check out this link to the work.  In that presentation he showed that wood under tension, known as reaction wood, has thicker cell walls and is denser than wood on the opposite side of a branch.  By comparison, the growth rings on the straight trunk are well centered and evenly sized.

Can you help me identify this tree?

I was not able to identify the dead tree that was knocked down.  It has light colored bark that is generally smooth, but cracked into smaller pieces.  The interior wood is evenly white and it was very easy to split. There were no smaller limbs remaining to see the branching pattern.  I welcome any suggestions as to what this might be.  I think there are additional specimens out there which I will check out once the snow melts.

No comments: