Florida has received an exceptional amount of rain this summer that has led to flooding on our rivers, creeks, swamps, and other low lying areas. Although trees require water to grow and stay healthy, too much of a good thing can stress our trees causing growth loss, disease, insect outbreaks and in some cases death.
A few tree species, such as bald cypress, is adapted to frequent flooding and will survive this excessively wet summer without harm. However, many of our trees will be stressed for several years even after the high waters recede. The first symptoms usually noticed are leaf yellowing, shoot growth, crown die-back and defoliation.
There are many factors that determine if a tree will survive flooding including species, age, vigor, flood duration, location, soil characteristics and the time of year. Once a tree becomes weakened, it is more prone to insect and disease damage. When the ground becomes saturated, conditions are ideal for fungal problems that lead to root rot diseases. Flooded soil conditions promote reproduction and dispersal of these fungi but also promote the susceptibility of roots to infection. Saturated soils also reduce soil oxygen levels that may cause some roots to die leaving the tree with a smaller root system to recover from the stress.
Many wood boring insects also benefit from weakened trees. Flooding causes widespread reduced resistance to insect damage all at once, creating ideal conditions for wood boring insect populations to reach epidemic levels.
The best way to help flood stressed shade trees in a yard or park is to increase its vigor and prevent other stress factors. There are several ways we can improve tree vigor in our yards, but due to economic returns and practicality this does not apply to pine plantations.
The first thing you can do to help your shade tree is to remove any sediment that may have accumulated. Next, consider aerating the soil so that roots receive the oxygen they need. Once the flood water recedes and rainy weather stops, consider applying light applications of fertilizer during the growing season to help keep your tree growing and healthy. Remember trees need several years to recover from flood damage, and Florida could experience drought again before the tree recovers. While large, established trees typically do not require irrigation, it may be necessary to water your tree for the next few years during times of drought. Also, consider limiting pruning activities and foot/vehicle traffic around the base of the tree for the next few years since it could cause additional root damage.
For more advice on flood damage to your trees, please call Baker County Forester Andy Lamborn at (904) 259-5128 or e-mail firstname.lastname@example.org.