DATE:    10/7/99
CONTACT: Dr. Don Ham, (864) 656-2480
EDITOR:  Giles Singleton, (864) 656-3876

Saving Trees from Drought and Heat 

     CLEMSON -- While rain has returned to most of the state in
recent weeks, the extreme heat and severe drought experienced
throughout South Carolina this summer placed tremendous stress on
landscape trees. Many are still suffering.
     Organic mulch around trees will improve water infiltration
into the soil and reduce the amount of water that runs off during
fall and winter rains. The mulch will also help conserve soil
moisture during the next hot, dry summer, assuring that more
moisture is available for tree growth for a longer period.
Mulching newly transplanted and young trees is especially
important, since water is usually the limiting factor in 
successfully establishing new, healthy landscape trees.
     Fall is a good time to replenish mulch around your landscape
trees or to apply it for the first time. During the warm summer
months, organic mulch decomposes, making beneficial elements
available for tree growth but reducing some of the other
attributes of mulch.
     Mulch is simply organic matter applied over the root zone of
a tree. The larger the mulch area, the better it is for the tree.
Mulch acts as a blanket to hold moisture, protect against harsh 
soil temperatures, help prevent mechanical injury from mowers and
string trimmers, and reduce competition from grass and weeds. A
two- to four-inch layer is ideal.  
     Good choices are wood chips, shredded bark, shredded leaf
litter, or pine straw. Remember, organic materials do not have to
be composted before using if they are applied as surface mulch.
Additional nitrogen is not needed unless "green" or non-composted
organic material is incorporated into the soil.
     Mulch should be placed at a uniform depth, and care should
be taken so that none is against the tree trunk. Putting mulch
against the trunk may cause disease problems on the living bark
at the base of the tree, especially with young trees. A mulch-free
area, one to two inches wide at the base of the tree, is
sufficient to avoid moist bark conditions and prevent infection. 
     Avoid creating  "mulch volcanoes" too commonly seen around
young landscape trees.
     Mulching large areas around mature trees, out as far as the
branch spread or drip line, is also very helpful. Often mulching
is the only treatment that will prevent or reverse the health
decline so common in mature trees in our harsh urban
environments. Mulch improves soil conditions so new root growth
is increased along with the overall health of the tree. 
     Using mulch is a simple concept that works. Nature does it
every day in the forest!   Dr. Don Ham, Extension urban forestry 
specialist.
     For more information on urban tree care, check out
http://depts.clemson.edu/extfor/programs/urban_tree_care/
or  http://depts.clemson.edu/for/arboriculture.htm . 
                  ***********************
     If you have questions or comments on gardening-related
issues, write to PSA News & Publications, Box 340129, A-101 Poole
Agricultural Center, Clemson University, Clemson, S.C. 29634-0129. 
     You might also want to look for other "Buds and Blooms"
columns under 1999 News Releases at: www.clemson.edu/agcomm . 
                              END