Written by:
Certified Arborist Will Martens WI-0646A
Why do forest grown trees have a longer life than trees in the urban forest?
American Forests estimates that the average life expectancy of a downtown urban street tree is just 13 years, while their forest counterparts can live up to 100 years or more.
-Jun 24, 2019
What is the reason for this difference?
First, a note about planting: If the tree plant is planted with a basket or burlap, or if it’s planted too deep or way too shallow then it’s going to need help to live a long life. Once it has been planted, there are many ways that the urban environment can impact the tree. Much of the trees vulnerabilities are associated with the soil in which it is growing.
Activities in an urban area can change a soil’s physical, chemical, or biological characteristics. Construction and landscape maintenance are the most common of these. The activities related to construction and landscape maintenance result in soil compaction, diminished fertility and major changes to the ways that the soil drains. Drainage problems, coupled with poorly timed irrigation systems can cause soil moisture problems. Foot traffic from pedestrians and lawn mowers compact the soil. All of these resulting issues can lower the life expectancy of urban trees.
Though it may sound like these forces are far too much to overcome, that is not the case! There are a number of practices and products that can help a tree live longer in the harsh urban environment. The answer to soil compaction is the Air-spade. This tool uses compressed air to gently blow away the soil from the roots. Even heavily compacted soil is no match for the 120 psi that the air-spade can produce. Once the roots have been exposed, an arborist can examine the roots and make a determination if any root procedures are needed. The removal of stem-girdling roots on poorly planted trees can correct old mistakes and give the tree a better shot at a longer life. Mulch can be mixed in to change the soil profile and keep compaction from happening again. Growth regulators can be used to help the tree develop more fine fibrous roots which will help the tree take up more of the nutrients that are available to the tree in the soil. Fertilizers can increase the fertility of the soil.
In fact, it has been shown that trees living in urban conditions can be helped to grow even faster than their forest-grown counterparts. But we don’t want them to live fast and die young. There are many tools available to help your trees battle the conditions present in the urban environment and Hoppe Tree Service can help. Our Certified Arborists are trained in the diagnosis and treatment of problems associated with living in the urban forest. Contact us today.
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