Tree Care After Storms: Signs of Damage and How to Help

trees in a street in Bristol submerged in water

The good news is that most trees are extremely resilient and adapt well to changing weather conditions over time–except when abrupt changes happen all at once! Let’s take a look at what types of sudden changes in weather can resort to damage to your trees, how to look out for signs of such damage and then how to help your trees recover from them. We always advise engaging a tree surgeon like Top Tree Surgeons Bristol for further advice or if tree removal ends up being the outcome.

Storms can be either very strong gale-force winds and/or ones that also result in flooding. The impact of a storm on a tree and shrubs is mostly influenced by wind speed and direction and the duration and amount of rainfall. The age and health of a tree and how exposed it is to the elements can also influence how much it is able to weather a storm. Flooding can also impact a tree less if the occurrence is in winter when the tree is dormant as opposed to summer when it is actively growing.

Storms that result in flooding

Some areas naturally experience flooding on a regular basis each year. The trees native to these environments are able to withstand floods because they have evolved to be able to survive wetter environments and extended periods of submersion in water. The problem occurs when non-native trees which are not appropriate for the environment or have yet to adapt to the environment are introduced. Alternatively, areas that previously had little to moderate rainfall might now be experiencing more flooding incidents due to a change in weather conditions.

Negative impact of flooding

Flooding has a number of negative impacts on trees as addressed below.

Reduction in soil oxygen

As oxygen is gradually replaced with water, flooding causes a reduction in the amount of oxygen in the soil content. This prevents the tree roots from accessing adequate amounts of oxygen. The high levels of moisture also contribute to competition for air in the roots zone. The waterlogged roots, and the death of root hairs results in reduced water and nutrient uptake for the plants once the tree is no longer water clogged. A qualified arborist can tell you whether there has been root dieback.


Vulnerability to diseases

The root system’s ability to defend against pathogens is also reduced during a flood event, which means that the tree becomes more vulnerable to diseases externally and from within. Flood events can also lead to high levels of bark beetle infestation as they are attracted by trees weakened by flooding. The beetles chew through the trunk in search of food sources such as cambium and xylem tissue where larvae hatch and grow before cutting off nutrients to the rest of the tree resulting in death.

Root rot

High water tables associated with flooding promote root rot due to lack of oxygen in the soil.

Breakdown of soil structure and nutrients

The impact of flooding on soil structure is also a major concern, as flooding results in loss of organic material and loosens soil, making it less able to support the tree. Flooding often results in landslides which can cause additional damage or topple trees that have already been weakened by flood events. Flooding can remove nutrients from soil, as well as create anaerobic conditions which prevent nitrogen-fixation and reduce carbon content.

Changes in soil pH

Soil pH is key to the survival of plants. The right soil pH ensures that the maximum amount of nutrients and chemicals are carried in the soil ready for absorption by the plants. Water clogged soil that’s alkaline in nature decreases in alkalinity and naturally acidic soil increases in acidity. This prevents the existence of adequate soil nutrients and chemicals needed by the plant to heal.


Moving debris

During a flood, debris, sediments, sand and other objects are carried that can cause physical damage to the trees.

Signs of flood damage on trees

It may be useful to enlist the help of an arborist to assess the symptoms being exhibited by the trees. Symptoms of tree damage can resemble signs of other conditions and might not present themselves until two years after the event. If you are aware that flooding has taken place, then here are sure-fire signs to look out for when examining your trees:

1. The tree might have come into leaf much later than expected. New leaves might be underdeveloped when they do come through. Leaves may have oedemas on them or turned yellow showing the absence of Chlorophyll, a process called chlorosis. As a result of root dieback, it might be difficult for a plant to absorb water, despite the flood. This can result in the leaves having a burnt and brown appearance.

2. The roots may be discoloured and adventitious roots might have also developed at the root crown in response to the stress of being submerged.

3. The bark can start to turn grey and it might also be peeling away from the trunk or branches because the water has travelled up the tree trunk and entered through cracks in the bark where it can lead to rotting.

Caring for flood damaged trees

It is not always clear right away if a tree that has been waterlogged will survive. It could die right away or die slowly over a few years. Sometimes it is clear right off the bat that the tree is dead, unstable and requires felling. Other instances, it might be best to wait and see whether the tree springs back into life, providing it isn’t unstable and posing a risk of toppling. It is advisable to seek the advice of a professional arborist about pruning the tree to stimulate growth. To stimulate growth, it might be helpful to prune the tree. Over-pruning can be a stressor for trees so do seek advice from a professional arborist about whether to do so.

Remove any build up of sand and slit. Apply mulch around the base of the tree to help remove excess water and cover any exposed roots with high quality top soil and composted material to increase nutrients and improve the soil structure. For more advice and care from a qualified arborist, contact Top Tree Surgeons Bristol.


Storms that do not result in flooding

When there has been no flooding but a storm has occurred, the main damage to the trees will be primarily from strong winds. When looking at storm damaged trees in general, first assess what type of damage has occurred. They may include the following:

– Fallen tree branches, downed limbs and broken tops and trunks
– Leaves ripped off from a site where they may not grow back again
– Branches and leaves might be strewn across your garden

If the damage to your tree is because it has been struck by lightning then expect the following damages:
– Leaves could be burnt and brown
– Branches may have been scorched or blown off completely, leaving only the charred stub of a branch

Caring for storm damaged trees

Regular tree maintenance can help mitigate against the damage caused by storms. The tree maintenance to prevent storm damage include:

– Trimming the tree of any branches that are dead or dying, which reduces weight on existing branches as well as reducing fire risk

– Pruning back to a natural shape and form so that winds can pass through without causing damage. This also increases air circulation around the trunk and root system

– Watering more during dry spells in order to reduce stress caused by water loss from leaves evaporating due to lack of moisture

– Fertilising with organic fertilisers such as compost for nutrient deficiencies caused by drought.

It is important to consider how your trees might be able to withstand any type of storm. Flood damage advice and regular maintenance from an expert arborist should add to the care tips shared above.

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