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Weekend Gardener: Trunk damage can girdle trees

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The farm looks like a storm hit recently but it’s really just my husband’s new deer deterrent technique.  It seems to be working.  In the past we have forgone the Irish Spring soap, human hair and coyote urine for more reliable barriers.  Tomato cages, tobacco stakes, wire, spiral plastic trunk wrap, and, yes, an occasional arrangement of lawn chairs have created distance between rutting and browsing deer.  
This year does not seem as bad as year’s past.   I think it is the barking Maremma livestock guardian dog out in the pasture!  We have protected trees, none the less, especially any newly planted in 2012.
I like the country and the deer that roam about but I do not damage to trees so we have a system.  Their hunger sometimes rips trees from the ground; other times they just do a sloppy pruning job.  Their rutting is the worst as the bucks practice their battle moves on the small trunks of young trees, scraping the bark clean off.  If only one side is damaged we wait; if the entire circumference is gone then we have learned to remove it and move on.  They never recover no matter how patient we are.  When the bark and cambium layer of a tree is removed all the way around then the tree is essentially girdled.  No movement of moisture or nutrients will pass the wound.  
So, our new technique to protect trees (since we have run out of all the other devices previously mentioned) is to pile broken branches, twigs and Christmas tree boughs around the base of the trunk.  We prop some against the trunk and lay the rest around the base to create somewhat of a cattle guard.  So far, so good, but it does look funny.
Even if you don’t have deer pressure in the garden there are other circumstances that can result in a similar girdling effect.  Rodents chewing the bark off at the base of the trunk can result in dieback.  When trees are girdled at the base like this they sometimes sucker from the roots.  If the roots are well-established and healthy then I would train one of the suckers as a new main leader; but this time put some wrap or barrier around the base.  When using conventional tree wrap it is important to remove it in the spring.
Oddly enough, a southwestern exposure during the winter can cause some damage.  Sun scald is common during winters when the temperature fluctuates dramatically night and day.  A frigid night followed by a warmish, sunny day causes the bark to split open.  If there is an elongated split on the southwest side (where the sun is) then you likely have a case of sunscald.  A healthy tree can compartmentalize the wound and heal; but trees under stress may find that one more injury is the straw that broke the camel’s back.  Tree wrap and plastic spirals can offset sunscald but, again, remember to remove the protection in the spring.
Girdling of roots can also cause problems for a tree but this damage takes place beneath the soil where we can’t see the problem.  In fact, trees that are planted too deep (which are probably the majority) have a higher incidence of girdled roots; and container grown trees may develop girdle roots in the pot.  So, when you plant a tree check the roots thoroughly for any roots that appear to be wrapped around the base of the trunk or other roots. Do not be afraid to cut these roots away even if they seem larger than the other roots.