Water-saturated soil can cause root rot, asphyxiate, kill, or prevent a tree from getting enough nutrition and oxygen because trees get air and nutrients through their roots. In addition, standing water can make the soil too spongy, causing roots to lose grip. So how long can trees last in standing water?
Most tree species can endure standing water for one to four months in the dormant season. However, one to two weeks of flooding during the growing season, particularly during warmer weather, can seriously damage less tolerant as well as young trees and even kill some species.
Read on for a detailed view of how standing water affects your trees and how long they can last in it. We’ll also look into rehabilitating flood-affected trees and recomposing the soil.
Effects of Standing Water on Trees
For all intents and purposes, standing water drowns your trees. The water directly damages the roots, and weakens trees over time. Trees affected by standing water may even show stunted growth for years.
When still water inundates a tree’s roots, it prevents them from breathing normally, which leads to wilting and disease. Let’s take a more detailed look at how standing water affects a tree.
Oxygen Starvation
Normally, trees use the water they absorb from the ground through their root systems for vital functions such as photosynthesis, transpiration, and respiration. However, a tree can drown in too much water, leading to death.
Insufficient oxygen prevents roots from growing and functioning properly, eventually killing them. However, dense, woody roots are more likely to survive a flood than thin, slender ones.
Dead roots leave scars on the tree, through which pathogenic fungi can penetrate and cause disease.
A tree that has lost too many roots due to illness or direct flood damage is more susceptible to drought in the next growing season. Additionally, it loses its strength gradually until it cannot survive strong winds.
Disrupted Soil Microbial Balance
Standing water lacks oxygen. Therefore, it prevents the growth of fungi such as mycorrhiza, which boosts trees’ root network expansion and food intake. These fungi require high soil oxygen levels to survive.
Not only does standing water inhibit the development of beneficial fungi, but it also promotes the growth and multiplication of harmful fungal pathogens, which cause water-borne tree diseases, such as:
- Pythium
- Fusarium
- Phytophthora
- Downy mildew
Insects are attracted to stressed trees because unhealthy trees have reduced tannis and alkaloids, making them easier to digest for insects like borers.
Standing Water Causes Toxic Gas Accumulation
Standing water hinders air circulation around the root system. Because of this restriction, the trees build up dangerous gases like nitrogen, hydrogen, and methane around their roots. As a result, the roots’ ability to feed and aerate the tree eventually declines due to suffocation.
Long-term flooding will eventually result in the death of additional roots. The tree will become weaker because of this circumstance. More roots will die with an extended stay, eventually killing the tree.
Signs of Damage Due to Standing Water on Trees
You should be able to tell if trees with less woody roots will survive within one to two weeks of standing in stagnant water. Impacted trees will start to exhibit damage. Woody plants, however, might take more time (one to two months) to show any symptoms.
The signs of trees overstaying in stagnant water include:
- Leaf wilting
- Branch dieback
- Yellowing or browning of leaves
- Leaf curling and pointing downward
- Reduced new leaf size
- Early fall color
- Defoliation
In the worst scenario, a tree may slowly deteriorate and eventually die over the next few years.
The long-term indicators of standing water harming your tree can be similar to those of underwatering or drought situations.
While some trees never fully recover from flood damage, others might do so in as little as a year. However, trees that experience flooding may become more vulnerable to subsequent problems, such as the growth of fungus and infestations of wood-boring insects.
How To Rehabilitate Trees Affected by Stagnant Water
A flooding event will highlight any spots on your property where the water collects or drains too slowly. Here are steps you can take to get rid of stagnant water and rehabilitate the trees already affected by the flooding.
Redirect Water Away From Your Trees
Check the downspouts on your property and see if any rainwater is falling from these spouts onto your trees. If so, adjust them so the water is drained away instead of collecting in and around your trees.
You can also build a French drain which is great for carrying away surface water from areas prone to flash flooding. The layers of stones and shingles in the French drain will ensure that water doesn’t stagnate around your trees.
Remove Debris and Damaged Limbs
First clear the water, then clean up the area and return it to its normal state as much as you can.
Remember to clear out any silt deposited by the flooding as it can damage your trees if its thick enough.
Make a recovery plan for your tree depending on what type it is, and what its requirements are. For instance, a tree that is used to wet conditions may not need as much work as a tree that typically grows in arid areas.
Deal With Unstable and Diseased Trees
Waterlogged soil is a safety hazard. Once soil is saturated with water, its structural integrity and compaction is affected. Trees in standing water may also develop sodden roots as we’d discussed earlier, which means that these trees might be in danger of tipping over.
Remove the dead and dying trees and limbs before falling on their own and causing damage, and contact professionals for immediate removals. Do not apply pruning paint or sealer.
Recompose the Soil
Use a rototiller to break the soil in the affected region.
Apply mulch, compost, or other organic material over the soil you disturbed before turning the rototiller on it once more. This procedure ensures that the soil is not compacted, lets air into the soil, and adds water-absorbing organic material to help with water drainage.
Prevent Diseases and Pests
Many tree diseases, pests, and insect infestations occur in humid, moist weather. To reduce the odds, remove any dead or dying branches that could serve as an entry spot for disease-causing organisms or insect pests. Use appropriate disease control measures and monitor for pest infestation.
Plant Flood-Tolerant Tree Species
Do you live near a floodplain? If, despite taking all the necessary precautionary and preventive measures, your site still keeps stagnant water, then planting bottomland or floodplain tree species is a sound alternative for you.
Some trees that can tolerate standing water include:
- Elms
- River birch
- Red maple
- Bur oak
- Sweetgum
- Eastern cottonwood
Read this article for a list of trees and their level of tolerance to flooding: Can Too Much Water Kill a Tree? What You Should Know
Frequently Asked Questions
- Are there fruit trees I can plant in water? Yes. Pawpaw, Jackfruit, Monkey Jack, and Carambola are fruit species that can tolerate waterlogged conditions to some extent.
- Which trees can I grow in a swampy area? Perennial Joe, Pye weed, Horsetail, Corkscrew rush, Northern Blue Flag, Papyrus, Marsh marigold. Swamp Sycamores, Bald Cypress, and Swamp Magnolias (Magnolia virginiana) are a few examples of trees that thrive in swampy, moist environments.
- How long should I water my trees? If you just planted your trees, you should water them more frequently than established ones. Once the roots have grown out and your trees are settled, you can water them weekly.
- Can sun-heated stagnant water harm my trees? In hot, sunny weather, stagnant water, especially if it is shallow, can heat up and kill young trees in a matter of hours. Remove extra water as soon as possible to give trees the best chance of surviving after floods.
In Conclusion
Your trees’ physical and physiological harm from a flooding incident may take two to five years to completely heal. Continued soil moisture monitoring and protection from pests and pollution during the restoration phase will help the soil’s regeneration process. Check your trees often for any issues.
If the tree begins to yellow or loses leaves on a sizable portion of its limbs, see an arborist to determine if your tree can be saved or if it should be cut down before it falls over.
