Drought is a common occurrence in many parts of the world. The lack of rainfall can cause plants, including trees, to suffer from drought stress. This can lead to several problems for the tree, including decreased growth, early leaf fall, and even death. In this blog post, we will discuss the signs of drought stress in trees and what you can do to help protect them from this condition.
Is it really a drought?
What classifies a drought? The term is loosely used to signify a period without proper rainfall and lack of adequate water. But are you going through a drought? According to the National Drought Mitigation Center, a drought is “a prolonged period of below-average precipitation in a given region, resulting in prolonged shortages in water supplies.”
Droughts can be further classified as:
Meteorological: A meteorological drought is defined as an extended period of abnormally dry weather conditions. Meteorological droughts are usually declared when an area experiences 70% or more days with less than normal precipitation.
Agricultural: An agricultural drought occurs when the lack of moisture affects crop production. Agricultural droughts can also impact livestock and forestry.
Hydrological: A hydrological drought happens when surface and subsurface water resources decline significantly. This can happen due to a lack of rainfall or increased demand from humans and animals.
What are drought stresses?
Drought stresses are plants’ physiological changes in response to drought conditions. These changes can negatively impact the plant’s growth, development, and survival. Some of the most common drought stresses include:
- Reduced photosynthesis: This is one of the most important effects of drought stress on plants. Photosynthesis is the process by which plants convert light into energy they can use for growth and development. When there is not enough water available, plants cannot open their stomata (pores) to take in carbon dioxide from the atmosphere. This reduces the photosynthesis that can take place, ultimately slowing down the plant’s growth.
- Stomatal closure: As we just mentioned, one of the main effects of drought stress is stomatal closure. Stomata are tiny pores on the surface of leaves that allow gases to exchange between the atmosphere and the leaf. When water is scarce, plants close their stomata to prevent further water loss. This can reduce the amount of carbon dioxide the plant takes for photosynthesis, ultimately slowing down growth.
- Wilting: Wilting is another common effect of drought stress. When a plant doesn’t have enough water, its leaves will droop or wilt. This happens because the plant’s cells cannot hold onto enough water, causing them to collapse. Wilting can lead to leaf drop and reduced photosynthesis.
- Leaf drop: As the name suggests, leaf drop is when a plant sheds its leaves prematurely due to drought stress. This can happen due to wilting or as a way for the plant to conserve water. Leaf drops can lead to reduced photosynthesis and growth.
What are the signs of drought stress in trees?
There are several signs that you can look for to determine if your tree is experiencing drought stress:
- Reduced growth: One of the most common signs of drought stress in trees is reduced growth. This can be evidenced by smaller leaves, shorter branches, and slower overall growth. Trees may also produce fewer seeds or fruits during periods of drought stress.
- Early leaf fall: Another common sign of drought stress is early leaf fall. This can happen due to wilting or as a way for the plant to conserve water. Leaf drops can lead to reduced photosynthesis and growth.
- Wilting: As we mentioned, wilting is another common sign of drought stress. When a tree doesn’t have enough water, its leaves will droop or wilt. This happens because the plant’s cells cannot hold onto enough water, causing them to collapse. Wilting can lead to leaf drop and reduced photosynthesis.
Trees experiencing drought stress may also exhibit other symptoms such as yellowing leaves, bark shedding, and increased susceptibility to pests and diseases. Drought also has several long-term effects. If drought conditions persist, trees may eventually die.
If you think your tree is experiencing drought stress, it’s important to take action immediately. Some of the things you can do to help your tree include:
- Watering: One of the best things you can do for a drought-stressed tree is to water it deeply and regularly. This will help replenish the tree’s lost water and encourage new growth.
- Mulching: Mulching around your tree’s base will help conserve moisture and protect the roots from heat stress.
- Fertilizing: Applying a slow-release fertilizer can help trees recover from drought stress by providing them with the nutrients they need to grow.
- Pruning: Pruning can help reduce stress on a drought-stressed tree by removing dead or dying branches. This will also help the tree to direct its energy toward new growth.
If you take these steps, you can help your tree to recover from drought stress and encourage new growth. Remember, it’s important to act quickly if you think your tree is experiencing drought stress, as these conditions can lead to long-term damage or even death. For more information on how to care for your trees during periods of drought, contact a certified arborist in your area. Understanding drought stresses in trees is important for proper care.