Published: July 18, 2009 05:11 pm      

Answers To Go: How to help trees survive the drought

Each week hundreds of people call or visit the San Marcos Public Library to find information. “Answers To Go” highlights recently received questions. Please visit the library at 625 East Hopkins, call 393-8200 for information over the phone, or e-mail us through our Web page at www.sanmarcostx.gov/library.



Q. My trees are beginning to lose their leaves. What’s the best way to water trees? Is there anything else I should be doing to reduce drought damage?



A. According to the folks at Texas A&M, you are correct in interpreting the likely cause of your leaf loss: “Early signs of drought damage are yellowing leaves and premature leaf drop all over the crown.

“As the damage progresses, leaves will die from the bottom of the tree upward and from the inside of the canopy outward. Sometimes leaves simply wilt, or "burn" along their edges.

“Trees need a deep, thorough soaking. A watering schedule that is adequate to maintain a lawn will not maintain a tree.

“Marty Baker, a Texas Agricultural Extension Service Horticulturist, recommends applying water in a donut-shaped pattern starting three-to-five feet from the base of medium to large trees, to about five feet beyond the tree's dripline.

“Drought stress also can be relieved by removing any weeds and grass beneath trees - which compete for water - and replacing them with a three-to-four inch cover of mulch.” (Source: http://easttexasgardening.tamu.edu/tips/trees/helptree.html)

Apparently Colorado residents have their own Aggies. They provide directions on mulching around trees: “Use 4 inches of organic mulch to reduce moisture loss. Pull back mulch 6” from the trunk of the tree.

“Use wood chips, shredded bark, leaves or evergreen needles as mulch – avoid the use of stone or rock near trees as this increases air temperatures and moisture loss from leaves and stems.” (Source: www.coopext.colostate.edu/4DMG/Trees/caring.htm#2)

It is very dry and very hot. We may see some trees lose all their leaves. Does that mean those trees are dead? Not necessarily.

Let’s return to our Texas A&M experts: “Drought-stressed trees may exhibit signs of dieback or decline. This may be the tree's way of coping with a stressful situation. If the roots are unable to supply enough moisture and nutrients to the crown of the tree, the crown will usually begin to die back to bring the tree's crown and root system into a more favorable balance.

“It should be mentioned that it is often difficult to determine if a tree has died from drought stress or has simply become dormant and appears to be dead. Two simple tests can be done to help determine if a drought-stressed tree is alive or possibly dead.

“First, collect some small twigs about one-eighth inch in diameter and try to break the individual twigs. If they snap and break like dead, dry twigs it could mean the tree has died.

“On the other hand, if the twigs bend and don't break with a snap, the tree may still be alive. Second, use your fingernail to scrape bark from a small twig or branch. If the tissue under the bark is green and moist, the tree may still be alive.

“To be absolutely sure the tree is not dead, wait until the next spring to see if it sprouts a new crop of leaves.” (Source: http://txforestservice.tamu.edu/main/popup.aspx?id=1283



Early signs of drought damage are yellowing leaves and premature leaf drop.