Drought and Heat May Have a Long-Lasting Effect on Urban Trees

Easter red cedar vs Leyland cypress

Native Eastern Red Cedar (left) has proven to be more drought and heat tolerant than it’s non-native counterpart, Leyland Cypress (right)

It may be a few years before we fully understand the impact of last summer’s drought and heat on our urban forest.  The immediate effect is quite blunt.  Whether from relentless heat or lack of water, many trees have died.  The most obvious losses include Southern Magnolias, Leyland Cypress, Japanese Black Pine, and other broadleaf evergreens and conifers that continue to retain their damaged brown foliage.  It will be May before we can better assess deciduous trees.

We have made some early observations that could help you in caring for your trees or factor into selecting replacements.  Trees that are generally in good health have not been as negatively impacted by the drought and heat as those already stressed.  This is apparent when comparing mistletoe infested Cedar Elms with their clean counterparts.  The same can be said of Bradford Pears and other trees that are highly susceptible to Cotton Root Rot.

Trees native to North Central Texas fared better than most introduced tree species.  Post Oaks are the first to come to mind.  Even on non-irrigated sites, Post Oaks’ leaves remained glossy and green until fall.  Pecans seem to have fared well, too—some even producing a crop.  The exception to this observation would include Crepe Myrtles.  From the old standards to the latest improved varieties, Crepe Myrtles are proven tree selections.  However, Silver Maples have reconfirmed their place as a poor choice for local landscapes.

Magnolia Heat and Drought stress

Heat and drought damage to many Magnolia trees is severe enough to consider removal

Mulch continues to serve as a tree care staple.  A simple 2 to 4 inch layer of mulch covering a tree’s critical root zone retains moisture and insulates soils.  Both newly planted and well-established trees have benefited from the buffering effects of properly mulched trees.  There is added benefit in the nutrients made available to a tree’s root system when mulch decomposes into compost.

Adequate watering, regular fertilization, and appropriate tree care are practices that have a measurable effect on a tree’s ability to address stress.  Should you have questions or concerns about the trees in your landscape, a Certified Arborist is available to assist you.  Simply call our office or complete a service request.