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Thursday, September 20, 2012

Snap! A young pecan tree breaks in the wind.

     Last week we had a few summer thunderstorms that packed some pretty good winds. Following the storm, I found a young trees snapped in half (photo above). How frustrating!

     My first thought was to see if I could discover why this tree, out of all the trees on the farm, broke in two.  I took a close look at the fractured stump (photo at right). I noted that much of the break was splintered except for two areas of smooth breaks on the southwest side of the tree (yellow arrows). From the appearance of the wood, these smooth breaks were probably present inside the tree even before the tree broke over in the wind. This observation was cause for further investigation.
     I used a chain saw to cut through the trunk of the tree just below the break (photo at left). I found discolored wood on the south by southwest side of the tree. The tree became prone to wind breakage because nearly 1/3 of the tree's supporting wood was dead and starting to rot. What caused this wood decay? The sun.
     This tree was a victim of  overzealous tree pruning. To get lower limbs out of the way of mowing or other tractor operations, too many low limbs were removed from this tree all at one time. This exposed a previously shaded trunk to intense heating by the midday and afternoon summer sun. This heat build up on the south and southwestern portions of the trunk killed the cambium halting all wood and bark growth. The resulting dead tissues attracted wood rotting fungi and the tree was unable to heal over the sun-scalded trunk.
   Now that we've lost the entire top of this young tree and the remaining stump is severely damaged by wood rot, I've decided to cut this tree off at ground level and allow a stump sprout to form a new trunk. In a couple of years, we'll need to re-graft the tree. With all the root energy this tree will have to push new growth, we should be back to nut production in no time.