Abiotic Problems of Trees

Abiotic Problems of Trees

Author(s): Mark Harrell, Rachel Allison, Laurie Stepanek
Photo of tree experiencing drought

Abiotic disorders are caused by nonliving events, such as drought stress, sunscald, freeze injury, wind injury, chemical injury, nutrient deficiency, or improper tree care, like overwatering or improper planting. Use this guide as a quick reference to help isolate your tree's issue(s). 

PDF Download
File DownloadDownload to Print

Scorch/Drought

Identification

  • Brown areas appear around leaf edges and extend into the area between leaf veins.
  • Needles turn brown uniformly, beginning at the tip.
  • On needles, generally, no spots or bands are present in areas that are still green.
  • Green color fades from needles.
  • Spruce needles may redden, especially in areas facing south and the upper side of branches.
  • Symptoms are more common in late summer, in years with low rainfall, in areas with hot, reflective surfaces (pavement, brick) and in newly planted trees.

Control

  • Provide additional water—generally about 1 inch each week during the summer over the root area if not provided by rain.
  • Mulch with wood chips or bark chips.

Sunscald

Identification

  • Long, vertical trunk injury on the south or southwest side of the tree.
  • Most common on recently transplanted trees or those planted too deeply.

Control

  • Improve tree health by mulching with wood or bark chips and watering about 1 inch per week.
  • Avoid overwatering.

Girdling root

Identification

  • Tree in poor condition.
  • The trunk has no flare on one side at the ground.
  • Root is pressing into the trunk at the ground line or a few inches below.

Control

  • Remove the girdling root if it can be done without seriously harming the tree.

Sapsucker injury

Identification

  • Mostly on pines and spruces.
  • Holes about 1/4 inch in diameter in the bark in horizontal or vertical rows.
  • Caused by species of woodpeckers that feed on tree sap (sapsuckers).

Control

  • No direct control.
  • Improve health by mulching and watering about 1 inch per week. Avoid overwatering.

Roots too deep

Identification

  • Caused by the tree being planted too deeply or soil being added above the roots.
  • Tree in poor condition.
  • Branches die and the tree may die.
  • Trunk at the ground is straight-sided like a pole, without the normal trunk flare.
  • Branches may originate at or below the soil line.
  • The gap appears between the trunk and soil when a small tree is rocked back and forth.
  • The tree becomes more susceptible to diseases and insect pests.

Control

  • No treatment is very effective.
  • Tree health can be improved somewhat if part of the soil can be removed from above the roots without damaging the roots.
  • Very young trees can be lifted with a tree spade.

“Mower blight”

Identification

  • The bark is missing, damaged or loose near the ground at the level that would be hit by a lawn mower or string trimmer.
  • Large dead areas of bark may be present near the ground.
  • The tree may be in poor condition.
  • Branches may die back from the ends.

Control

  • Avoid hitting the tree with a lawn mower or string trimmer.
  • Place a mulch bed around the base of the tree to reduce the grass and weeds that grow there and eliminate the need to mow near the tree.

Chlorosis

Identification

  • On pin oak, silver maple and many other broadleaf trees and evergreens.
  • Leaves are yellow and may have green veins.
  • Yellowest leaves are at the branch tips.
  • Severely affected leaves may have brown areas.
  • Branches may not leaf out and eventually die.

Control

  • Provide iron or other nutrient known to be deficient with trunk injections, soil treatments, or sprays.*
  • Improve soil conditions by mulching with wood chips and watering about 1 inch per week.
  • Avoid overwatering.

Overwatering/ Saturated soil

Identification

  • Foliage may turn yellow.
  • Foliage may die and drop, especially in the interior.
  • The soil is very wet for days or weeks at a time.
  • Often caused by frequent watering.

Control

  • Water 1 inch per week, applied slowly at one time, or 1/2 inch applied twice per week.
  • Redirect excess water away from the tree.

Herbicide injury

Identification

  • Leaves and shoots may be distorted, discolored or dead.
  • Hackberry and oak leaves may have holes and ragged edges.
  • Often more than one species is affected.
  • Herbicide exposure may occur from drift or from being taken up by the roots from the soil.

Control

  • Identify the source of the herbicide and prevent another exposure.
  • Improve tree health by mulching with wood or bark chips and watering about 1 inch per week.
  • Avoid overwatering.

Winter desiccation

Identification

  • Mostly on evergreens.
  • Needles turn brown.
  • Browning is often more on one side of the tree in the direction of a heat source during the winter, such as the side of a building or rock groundcover.

Control

  • Promote good tree health by mulching and watering during dry periods of summer and fall.
  • Replace rock mulch with wood or bark chips.

Freeze injury

Identification

  • Leaves turn dark and limp after a spring freeze.
  • Branches fail to leaf out in the spring after a sudden early freeze the previous autumn or after a warm spell in the winter.
  • Evergreen needles turn brown in mid to late winter, often only on last year’s growth.
  • Bark may be killed and drop off.

Control

  • No direct control.
  • Improve tree health by mulching with wood or bark chips and watering about 1 inch per week.
  • Avoid overwatering.
Tags:
Tree issues