Archive for Thursday, June 26, 2008

Decline in tree’s health difficult to spot, even harder to reverse

June 26, 2008


Do you know a tree in your life that has become a friend? Maybe it waved its graceful arms when you passed by or welcomed you into the shade beneath its boughs.

Trees are amazingly resilient and often outlive their planter, but they do die eventually. One of the hardest things I ever have to do is to tell someone that their tree - their dear old friend - is dying.

In most cases, once decline is evident in a mature tree, it is too late to reverse the process. Decline is characterized by branch dieback, heavy seed crops and fall coloration early in the season. Sometimes fully developed leaves are smaller than average and more sparse on the tree. These symptoms may appear subsequently over a period of several years.

Tree decline and death in established plantings is almost always a result of a combination of factors. Weather-related incidents, like last year's late freeze, stress the tree but are not preventable. Summer droughts and moisture fluctuations reduce photosynthesis and deplete the tree's food reserves over time.

To keep your trees as healthy as possible, water over extended dry periods - even in the winter when temperatures are above freezing. Mulch the tree (doughnut-shaped rings) to reduce moisture fluctuations.

Avoid cutting into the roots for any kind of construction, and do not pile large amounts of soil over the root systems.

Be careful with lawn equipment. Injury to the base of the tree from string trimmers and lawn mowers damages the vascular system and wounds never completely heal. In extreme cases, this damage can completely kill a tree.

If you have a young tree that was planted too deeply, pull soil and mulch away from the base. You should be able to see the top of a horizontal root(s) emerging at the base of the tree if it is at the proper depth.

Test your soil. Nutrient levels and pH play an important role in the overall health of the tree. Many trees (and soils) in our area do not require additional nutrients.

Insects are more attracted to stressed trees than healthy ones, so keeping your trees healthy with good maintenance practices will lessen damage. Avoid planting species that are especially prone to borers and other serious pests.

Diseases are also more problematic in already stressed trees. Good pruning, and following the above maintenance, will go a long way in disease prevention.

Keeping your trees as healthy as possible will prolong their lives, but planning for the future is also a good idea. Plant new trees nearby (not underneath) before the old ones die so that they have some time to grow.

Questions about tree diseases and decline can be answered by Douglas County Extension Master Gardeners at 843-7058, 1 p.m.- 4 p.m. Monday-Friday, or by e-mailing anytime.

- Jennifer Smith is the Douglas County Extension AgentHorticulture for K-State Research & Extension. She can be reached at 843-7058 or <a href=""></a>.


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