Branching Out: Keeping A Healthy Environment Through Tree Care

Trees in Troubled Waters: Can Trees Survive Flooding?

Has your property and the surrounding area recently suffered flooding? If so, and if you have trees on your land, you are probably wondering whether your trees will survive or if you will need to hire a tree lopper.

Although flooding does kill trees, many factors will decide the fate of your tree in the aftermath of a flood. If you are worried about your trees due to a recent flood occurring in your area, the following considerations will help you to decide how best to approach the issue.

Tree Species Matters

In the Bolivian rainforest, annual floods caused by logjams kill just under 1,000 hectares worth of trees per year. If there are 2,500 trees per hectare, that equates to 2.5 million trees per year! The main cause of death is choking or suffocation. Tree roots require oxygen. Flooding deprives tree roots of oxygen and makes the soil more acidic.

Some tree species, however, can survive for weeks during a flood. Here is a short list of some of the most flood-tolerant trees:

  • Sydney blue gum (Eucalyptus saligna)
  • River red gum (Eucalyptus camaldulensis)
  • Swamp gum (E. robusta)
  • Red maple (Acer rubrum)
  • Silver maple (Acer saccharinum)

Many species of tree can only survive for a few days or less in flood conditions. Here are just a few of them:

  • Red oak (Quercus rubra)
  • Black oak (Quercus velutina)
  • White oak (Quercus alba)
  • Norway spruce (Acer platanoides)
  • Norway spruce (Picea abies)
  • Colorado spruce (Picea pungens)

Timing Is Important

Flooding that occurs when trees are dormant, which is typically in winter for most trees, may not do as much damage to trees as flooding that occurs during growing season. Many species of tree wake up in spring, producing leaves and blossoms. If their soil is disturbed by flooding then, they could die within a few days or suffer damage.  

Tree Health Plays a Part

Healthy trees—for example, those that have not suffered any recent diseases, pest attacks or over pruning damage—will fare better during a flood. If, for instance, a tree recently suffered through a drought during the summer months, a flood may finish it off.  

Adult Trees Fare Better

Young trees that are yet to establish a strong root system are ill-prepared to deal with flooding. The erosion of the soil around their roots, the increase in soil acidity and the lack of oxygen will be too much for a young tree to handle. Likewise, over mature trees, i.e. those that are old and failing, will not survive prolonged periods of flooding.

Well-established and virile adult trees stand the best chance of surviving a flood.

If you are worried about your trees, you should hire an arborist. A qualified and experienced arborist will be able to properly assess your trees and suggest a suitable plan of action.