3 July, 2016
The Ultimate Guide to Preventing Tree DroughtBy
Paul at Tree Care
As droughts continue to plague many areas of the country, homeowners are wondering: What can be done to keep trees healthy during unusual dry spells?
Do trees reside on your property? Are you worried your trees may unnecessarily suffer during the summer months when rain may not fall for weeks on end?
If you are lucky enough to have trees on your property, then it's only natural to raise concerns such as these regarding the welfare of your trees. After all, your trees are a living and breathing addition to your property, so raising these concerns and subsequently taking steps to maintain your trees really is the right thing to do.
In some countries, droughts last for up to 3-5 years in duration. If you live in such a country, it's essential you take precautions to protect your trees from dehydration and drought stress.
In this post, we outline steps you can take to keep your trees in good health, particularly during periods of severe drought. This includes keeping your trees hydrated and away from pests and disease.
How drought damages trees
Prolonged drought will initially damage your trees roots. Because roots are deep below the soil line, this damage will be invisible to you. Thus, many people will be totally unaware of this initial drought-inflicted damage that's occurred to trees on their property. It may take up to two years for the signs of drought distress to become visible to the naked eye.
However, evolution has dealt trees a generous survival mechanism in the form of closing leaf stomata. These stomates are designed to conserve water in times of drought, thus protecting the tree from total dehydration. However, if the drought is severe enough, the tree will deplete all of these water reserves to the point where the tree is no longer able to support itself. This is because feeder roots beneath the ground will die off due to dehydration.
This is a process known as ‘drought stress.' This process is more than capable of killing your tree. However, you will typically observe a number of tell-tale signs of this process before it is too late. For instance, you will notice undersized leafs, as well as a scored appearance in leafs. Many leafs will turn a dark colour, eventually dropping off.
When your tree is weak due to dehydration, it becomes vulnerable to pest attacks. Botanist believe pests are able to sense chemicals omitted from a distressed tree. This sends a signal to pests to attack the tree. Pest burrow into the tree in order to lay eggs.
To prevent pest attack, we recommend your apply a layer of wood chips over the root zone out to the drip line. This chip wood will conserve water for the tree to access. If you cannot buy chip wood, buy organic mulch instead.
Distressed trees are likewise vulnerable to attack by fungal pathogens. These pathogens are now able to bypass the trees defences because bark is weakened. Clumps of fungal pathogens effectively starve the tree of water.
When it comes to drought stress, certain trees are more vulnerable than others. Furthermore, recently transplanted trees are particularly vulnerable to drought stress. In fact, we recommend you supplement transplanted trees' water supply for at least two years after the transplantation took place.
Steps you can take to prevent drought stress
Now we outline steps you can take to reduce the risk of drought stress.
Step 1: Assess the situation for each tree
Apart from the size of your trees, here's a list of additional factors influencing how much water your trees will require to stay hydrated:
- Shade exposure
- Local climate
- Sun exposure
- Location of your tree e.g. on flat land vs. a dry slope
- How well the tree has been planted
- Competition for water from neighbouring trees and plants
Assess each of your trees' situation with reference to the above factors and concentrate on assisting those trees most at risk.
Step 2: Implement an irrigation system
The first step you should take is to ensure your trees are not likely to dehydrate. To achieve this, we recommend you utilise a soaker hose, drip irrigation or soil injections. These techniques are known as ‘deep watering'. Such equipment is purchased inexpensively from your local gardening shop. We recommend you deep-water your trees up to a depth of around one-foot. Furthermore, we recommend you water the tree around the drip line, and 3-5 foot beyond the drip line for evergreens. The aim is to get the water below the surface and towards the roots
Don't dig holes in the soil in an attempt to channel water to the roots. This action will do more damage than good to your tree.
Do not attempt to merely ‘water' your trees with a normal garden hose. However, an irrigation system or soaker hose is still a poor substitute for rainfall, particularly when your trees are very large. This is because your watering solution is unlikely to provide enough water to completely rehydrate your trees. As a general rule, you must supply your tree with 10 gallons of water per inch of trunk diameter. For large trees, it's unlikely you will be able to provide this much water unless you have access to an industrial irrigation system.
Step 3: Apply a layer of ‘mulch' to the ground surrounding your tree
Remove the lawn turf and replace this with organic mulch or wood chip. Mulch or wood chip preserves water much better than lawn turf. This means your tree will have more water to draw from as the drought continues. Furthermore, lawn grass consumes water before it reaches your tree. This forces trees to grow excess foliage grown to bypass lawn grass. This, we recommend you make life easier on your trees by removing lawn grass.
Step 4: Reduce excess foliage, weak branches, and diseased plant material by pruning the canopy of the tree
If you notice limbs are dying, it's essential for you to remove them without delay. This is because dying or died tree limbs are likely to contain deadly diseases or pest. These diseases and pest are likely to spread and could kill off your tree entirely.
Source: Liverpool Tree Care