Protecting Your Trees From Drought Stress with Oak Bros Tree Care!
McLean County is currently in a "severe drought", according to the U.S. Drought Monitor. A severe drought affects many plants trees, specifically, have a significantly harder time recovering from drought injury both during the current growing season and multiple growing seasons after. Subsequent droughts create a cumulative effect that some trees may never recover from. Droughts create a lack of soil moisture, which reduces a tree's ability to absorb water and nutrients.
As dry soil conditions persist, the small root hairs in the upper ~18 inches of soil that are responsible for the majority of water uptake begin to die. As these root hairs die the water absorbing capacity of a tree is greatly reduced. Newly transplanted trees suffer acute drought stress due to having a lower amount of fine roots removed during the planting process. Established and/or mature trees suffer from cumulative effects of drought. Below are the effects of acute and chronic drought stress:
- Leaves turning brown along the edges (scorch).
- Leaves turning yellow/brown and eventually falling off.
- Increased susceptibility to secondary insect infestations, particularly wood-boring insects.
- Increased susceptibility to secondary, root-rotting organisms, such as Armillaria and Phytophthora Root Rots, due to death of roots.
- Tree canopy declines due to root death.
What can homeowners do to help reduce drought stress on their trees?
Watering during drought conditions will be absolutely necessary. How much water a tree needs is not an exact science because all trees and soil types are different but the rule of thumb is that trees require at least 1 inch of rain per week. Water needs to be applied to the surface at a very slow rate for a long period of time; we refer to this as "low and slow". Open-end hoses with a pencil-thin trickle and soaker hoses are excellent methods of watering low and slow. 5-gallon buckets with a few very small holes drilled through the bottom can help you keep track of how much volume you are applying. For smaller trees, watering bags provide a known watering volume. These must be used carefully, however, to ensure the membranes inside the bags aren't clogged or broken.
What shouldn't homeowners do?
Watering only with lawn irrigation. Lawn irrigation systems are designed to run for a short period of time during the week. While this does provide moisture to soil, turf roots absorb the majority of the water applied. In addition, this encourages tree roots to grow closer to the surface which increases future drought injury susceptibility. Do not be encouraged to fertilize your trees, especially with nitrogen. Nitrogen stimulates the already-stressed tree to grow, expending resources it doesn't have, and increases susceptibility to insect infestations. As a rule of thumb, trees should never be targeted with a nitrogen-based fertilizer unless a soil and/or tissue analysis dictates a soil or leaf is deficient in nitrogen.
What can Oak Bros do to help reduce drought stress on your trees?
We've carefully designed our plant health care program around reducing drought stress and conditioning soils to function better during drought conditions so that your trees are able to thrive instead of survive. Below are a few services our Soil Program provides to reduce drought stress and susceptibility:
- Deep-root fertilization (spring and fall applications) with multiple carbon sources that increase the water-holding capacity of soils, which reduces drought susceptibility. In addition to carbon sources, we utilize plant specific plant hormones that promote the production of root hairs to aid in water and nutrient absorption.
- Vertical mulching: utilizing a high-pressured air-tool we create small holes under a tree's canopy to decompact soil, introduce oxygen, and stimulate root growth. These holes are filled with carbon sources which increase the water-holding capacity of soils, which reduces drought susceptibility.
- Soil application of a plant growth regulator. The plant growth regulators we utilize decrease a tree's twig length over a 3-year span in order to force the tree to use its "growing energy" for better tree health-related functions. Our plant growth regulator thickens leaf surfaces and promotes the production of root hairs, both of which reduce drought susceptibility.
- Consultation Services: Treatment without diagnosis is malpractice. Our plant health care team, led by our Board Certified Master Arborist, is highly trained in accurate diagnostic techniques that you won't find anywhere else in our region. An accurate diagnosis ensures that your trees receive the best management plan for past, current, and future stress; our soil program is built around reducing drought susceptibility so that your trees thrive.