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Is there something hiding in your tree? Have you seen it — under the bark, in the roots, in the wood, or maybe clinging to the leaves? How do you know if anything is there at all?
Can you tell the difference between healthy and unhealthy trees? Healthy trees are vigorous, resilient, and in balance with their environments. Unhealthy trees are stressed, have low vigor, and are otherwise out of balance with their environments. If you’re planting any trees, make sure they are the right species from the appropriate seed source and in the right location under the right environmental condition.
Diagnosis of pathogens — diseases, insects, viruses, bacteria, etc. — can be challenging. Symptoms, signs, and patterns of damage are vital to proper diagnosis. Symptoms are the tree’s response to the pathogen. These can be thinning foliage, decrease in growth rate, pitch streaming, yellow foliage, etc. Signs are evidence of the pathogen, such as insect galleries or fruiting bodies of the fungus. Is the pattern of damage only on one side of the tree, in the upper crown, on a single branch, in several trees close together, etc.?
To get started with diagnosis, you need to know the species of tree at which you are looking, the relative age of the tree, how it’s been growing during the past few years, any recent activity to the tree (fertilizing, pruning, chemical application, etc.), where the tree is located, and what part of the tree is affected. This is just for starters. The list of questions goes on and on.
Factors affecting tree health include biological factors (insects, diseases, or animals), abiotic factors (drought, wind, soil, temperature), and cultural practices (watering, pruning, fertilizing, spraying).
You should be familiar with your trees’ growth requirements. Know their tolerances to drought, shade, moisture, soil pH, heat, frost, etc. Knowledge of the common tree diseases and insects in your area will help you look for appropriate signs and/or symptoms of damage. You should also be aware that more than one pathogen can be present in a tree at a time. Some disorders interact with each other or predispose trees to other problems. For example, overcrowding may predispose a tree to root disease. Bark beetles and root disease are often found together, and it can be unclear which one entered the tree first.
Giving your tree proper care and protecting it from injury is a good step in keeping it healthy. Ensure trees have adequate, but not too much, moisture, control competing vegetation (grass, weeds, etc.) around bases of the trees, and reduce density of trees to provide suitable quantities of nutrients and water.
Remember that you want healthy trees, but also understand that some tree mortality is normal and unavoidable.
If you are interested in learning more about insect and disease diagnosis in your trees, join us on Feb. 16 for “Bugs & Crud: What’s Lurking in Your Trees.” For more information, contact our office at 672-4461 or register by e-mailing holly.burton@oregonstate.edu. The registration deadline is Feb. 12.
Can you tell the difference between healthy and unhealthy trees? Healthy trees are vigorous, resilient, and in balance with their environments. Unhealthy trees are stressed, have low vigor, and are otherwise out of balance with their environments. If you’re planting any trees, make sure they are the right species from the appropriate seed source and in the right location under the right environmental condition.
Diagnosis of pathogens — diseases, insects, viruses, bacteria, etc. — can be challenging. Symptoms, signs, and patterns of damage are vital to proper diagnosis. Symptoms are the tree’s response to the pathogen. These can be thinning foliage, decrease in growth rate, pitch streaming, yellow foliage, etc. Signs are evidence of the pathogen, such as insect galleries or fruiting bodies of the fungus. Is the pattern of damage only on one side of the tree, in the upper crown, on a single branch, in several trees close together, etc.?
To get started with diagnosis, you need to know the species of tree at which you are looking, the relative age of the tree, how it’s been growing during the past few years, any recent activity to the tree (fertilizing, pruning, chemical application, etc.), where the tree is located, and what part of the tree is affected. This is just for starters. The list of questions goes on and on.
Factors affecting tree health include biological factors (insects, diseases, or animals), abiotic factors (drought, wind, soil, temperature), and cultural practices (watering, pruning, fertilizing, spraying).
You should be familiar with your trees’ growth requirements. Know their tolerances to drought, shade, moisture, soil pH, heat, frost, etc. Knowledge of the common tree diseases and insects in your area will help you look for appropriate signs and/or symptoms of damage. You should also be aware that more than one pathogen can be present in a tree at a time. Some disorders interact with each other or predispose trees to other problems. For example, overcrowding may predispose a tree to root disease. Bark beetles and root disease are often found together, and it can be unclear which one entered the tree first.
Giving your tree proper care and protecting it from injury is a good step in keeping it healthy. Ensure trees have adequate, but not too much, moisture, control competing vegetation (grass, weeds, etc.) around bases of the trees, and reduce density of trees to provide suitable quantities of nutrients and water.
Remember that you want healthy trees, but also understand that some tree mortality is normal and unavoidable.
If you are interested in learning more about insect and disease diagnosis in your trees, join us on Feb. 16 for “Bugs & Crud: What’s Lurking in Your Trees.” For more information, contact our office at 672-4461 or register by e-mailing holly.burton@oregonstate.edu. The registration deadline is Feb. 12.
Raini Rippy is an extension forester for OSU Extension Service in Douglas County. She can be reached by e-mail at raini.rippy@oregonstate.edu or at 541-672-4461.
