Drought Conditions Lead to Tree Injury

Greater Boston is experiencing drier than average conditions and the U.S. Seasonal Drought Outlook predicts little chance for improvement. Taking a proactive approach for important plants can help prevent long-term damage or death. Supporting trees with proper cultural practices, monitoring for pests and disease, and reasoned care can significantly increase plant viability and survival. Greater Boston is experiencing drier than average conditions and the U.S. Seasonal Drought Outlook predicts little chance for improvement.  Image: WBZ Boston

Trees vary in their ability to tolerate drought. While all plants are at risk during long periods of drought, some are more susceptible. Drought affects plants in various ways. Drought stresses plant’s inner processes, often starting with root damage. Fine diameter absorbing roots can be compromised so drastically that trees are unable to absorb water.

As root systems begin to fail and unable to uptake water, a tree’s circulation becomes compromised. With less water and nutrients available for photosynthesis, it is unable to produce adequate food and what little food is produced isn’t available due to the compromised circulation, which can send the tree into a spiral of decline.

To compensate for the imbalance caused by root-loss, crown thinning and branch dieback within the canopy is common. Symptoms of drought injury may be sudden or take years to be revealed. Visual signs include: wilting, yellow, curling, marginally scorch leaves or drop early leaf fall.

Besides reducing growth, water stressed plants drastically decrease their resistance to opportunistic pathogens. Often, drought stress may not kill a tree outright, but set it up for more serious secondary insect and disease infestations in following years.   Bark beetles, borers, and other insects and pathogens infest stressed trees more easily than healthy, vigorously growing trees.

Visual signs of drought injury include: wilting, yellow, curling, marginally scorch leaves or drop early leaf fall.

Preventative actions are far more effective when preformed prior to a stressed state. To help protecting drought-stressed trees from pests a good practice is to maintain a 2-3-inch layer of composted, wood chip mulch over the root zone. This helps retain soil moisture longer and provides a nutritional source for the soil. Important trees may benefit from treatment to protect against wood-boring insects.

Prudent deep watering with soaker hoses, as opposed to brief, surface watering, is important. Effective targeted watering techniques are critical. Water trees and lawn separately as each has uniquely different requirements. Applying the right amount of water, based on the weather and tree needs, is the key to using water efficiently.

Care for drought stressed trees and plants

  • Learn the cultural requirements of your plants. Some plants are more drought sensitive than others
  • Know your soil. Observe how quickly soil dries out after a rain or watering.
  • Mulch plants with a 2-3 inch layer of organic mulch to reduce soil evaporation, temperature fluctuations and conserve moisture.
  • Irrigate slowly so water percolates down into the soil.  Infrequent, deep soakings are preferable.
  • Reduce the use of high-nitrogen fertilizers which contain salts that can damage stressed tree tissues
  • Prune out dead wood to reduce attacks by insect and disease pests.
  • Prevent any further stress from construction activities, lawn herbicide applications, or foot-traffic over the root zone.

Our Certified Arborists at BTSE can help assess your drought-stressed trees and work with you to develop a plan to help care for your landscape to mitigate the effects of drought.