oak death from drought

Oak trees dying due to drought

Updated: August 11, 2022

Abiotic factors that contribute to the decline of trees and shrubs

A plant problem that is NOT caused by a disease or insect organism is called an "abiotic" injury. 

  • Tree and shrub problems, to a large degree, are not due to diseases or insects. Professionally, the causes are often referred to as abiotic (Latin word meaning “without life”) causes. Simply, we can refer to them as stress factors.
  • It may take a long time for symptoms to appear or it can appear very suddenly. But, by the time it becomes obvious that a tree or shrub is dying, it is often too late to correct the problem.
  • Diagnosing abiotic plant problems can be difficult. Multiple factors may be involved, including evidence of insects or disease. 
  • There could be both abiotic problems and evidence of an insect or disease issue. As stressed plants are more susceptible to disease and insect infestations. 
  • Determining the difference between the “symptom” and the “sign” of a problem is the first step in making a diagnosis.
  • Careful site selection, proper planting, protecting trunks and roots from mechanical damage, watering during plant establishment, and during dry weather are some ways to protect plants from stress factors.
  • It is important to recognize stress symptoms early to prevent further decline.
  • Trees planted in natural areas and native soil have a much longer lifespan than trees planted in a typical home or commercial landscape.

Symptoms and signs

Symptoms

curled leaves from drought stress
Symptoms of drought-stress leaves, leaf curl and leaf scorch

A “symptom” is an unnatural change in a plant’s appearance or growth caused by one or more factors. Example: wilting of leaves or early fall color.

  • Small leaf size
  • Wilted leaves
  • Early fall color
  • Early leaf drop
  • Very slow growth
  • Poor foliage color
  • Scorched or leaves that appear burnt
  • Sparse growth
  • Branch die-back
  • Large crops of fruit or nuts
  • Development of suckers or water sprouts
  • Combination of any of the above
  • Death of the plant

Signs

cottony camellia scale
Cottony camellia scale, Brian Kunkel, University of Delaware, Bugwood.org

A “sign” is the actual presence of organisms such as insects, mites, or mushrooms. Examples: Insect droppings on leaves; the white coating on crepe myrtle leaves caused by the powdery mildew fungus.

  • Active insect infestation
  • Insect feeding damage
  • Evidence of insect's presence, like the remains of eggs or pupal cases
  • Mushrooms
  • White coating on leaves caused by powdery mildew fungus

Stress factors

Many of these issues will not kill plants but weaken them causing poor growth and potential failure to thrive. Sometimes they also predispose them to disease and insect problems.

Environmental

  • Air polution on ash

    Air Pollution Damage

  • Stewartia drought

    Drought and Excessive Heat Stress

  • tree with one branch showing fall color

    Early Fall Coloration

  • freeze damage to saucer magnolia

    Freeze damage

  • lightening strike damage on a tree trunk

    Lightning Damage

  • storm damage - broken tree branches

    Storm Damage

  • Magnolia foliage with winter scorch

    Winter Damage on Landscape Plants

Physical damage

  • sunscald damage on the trunk of a fruit tree

    Broken Branches and Lower Trunk Damage

  • Leaf scorch on dogwood

    Chlorine Toxicity

  • Construction damage on tree

    Construction Damage

  • construction damaged tree roots

    Damaged Tree Roots

  • guy wire embedded in a tree trunk

    Embedded Wires, Nylon Cord, and Wire Baskets

  • girdling root

    Girdling Roots

  • graft failure on cherry

    Graft Failure

  • herbicide damage on spruce

    Herbicide Damage

  • Natural Gas Injury

  • phytotoxicity symptoms on blue spruce

    Phytotoxicity Damage

  • damaged container plant

    Poor Quality or Damaged Plants

  • salt damage on juniper shrubs

    Salt or Fertilizer Damage

Poor plant care and site conditions

  • flooded tree

    Excess Water Problems

  • construction grade changes to tree planting

    Grade Change Problems

  • crapemyrtle poor flowering

    Trees and Shrubs Failing to Flower

  • nutrient deficiency

    Nutrient Deficiency

  • flooded soil under oak trees

    Poor Draining Soil and Site Problems

  • azaleas dying due to poor planting location

    Problems Due to Poor Care After Planting

  • Paths typically contain compacted soil

    Problems Caused by Compacted Soil

  • yellowing foliage due to low light

    Problems Caused by Low Light on Trees & Shrubs

  • tree planted too deeply

    Trees Planted Too Deeply

Miscellaneous

  • Algae and lichens on tree trunk

    Algae and Mosses (They do not kill trees or shrubs)

  • burls

    Burls (They do not kill trees)

  • yellowing needles on pine - normal needle cast

    Evergreen Foliage Yellowing (this can be normal)

  • surface roots

    Surface Tree Roots (This can be normal root growth)

    Photo: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

  • slime flux

    Tree Trunks with Wet Wood or Slime Flux

  • Walnut Toxicity - Juglone

  • water sprouts

    Water Sprouts or Suckers on Trees (Can be a sign of stress)

Additional resource

Mississippi State University | Tree Health Assessment and Risk Management

Adapted from publication HG 201 Homeowner Landscape Series: Common Cultural and Environmental Problems in Landscapes, Authors: Dave Clement, Ph.D., Principal Agent, University of Maryland Extension and Mary Kay Malinoski, Principal Agent (retired), University of Maryland Extension. And publication HG 86 Common Abiotic Plant Problems, Author: Raymond Bosmans, Professor Emeritus University of Maryland.

Edited by Jon Traunfeld, HGIC Director and University of Maryland Extension Specialist. Complied by Debra Ricigliano, HGIC.