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Pacific madrone is one of Douglas County's most abundant tree species, and one of the most abundant trees in terms of questions relating to health. The tree's location — usually on warm sites with shallow rocky soils — leads at least in part as to why so many questions arise regarding its general health. These marginal sites are a tough place for any tree to grow. Madrone is drought tolerant and well adapted to survive long, hot summers with little or no rainfall. Extended droughts, however, may reduce tree vigor and increase susceptibility to diseases.
There are three major groups of diseases that affect madrone: foliage diseases, branch dieback and trunk canker diseases, and, lastly, root diseases.
More than a dozen fungal organisms can cause leaf spots and dead regions on the leaves. These diseases may result in unsightly foliage and usually are not serious. What should you do? Pruning dead branches and raking fallen leaves before the fall rains may help diminish the spread of spores and infection to new leaves.
As for twig dieback and trunk cankers, these diseases are caused by fungi that kill the cambium (the growth layer inside the bark). Initially, the bark looks discolored, then peels off and reveals blackened, cracked wood that almost looks like it's been burned. Madrone twig dieback starts at the branch tips and is associated with drought. Madrone canker occurs on the main trunk or major branches and sometimes on smaller twigs. It usually develops after bark injury, causing cankers to grow around the trunk or branch, which may girdle and kill it. Oftentimes, twig dieback and trunk cankers are present on the same tree. Affected trees may decline rapidly and die in a year or two, but healthier trees may live several years or even decades. Again, what to do? Deep watering may help prevent twig dieback as well as minimize bark injury.
Third on the list are roots and tree trunk diseases. Cankers are usually located near the base of the tree, with a loss of foliage and small, curled leaves being common symptoms. Persistent, moist soil conditions favor the fungus, so trees growing in poorly drained soils are most susceptible. But what do we do?
The main way to avoid root disease problems for trees in your yard is to avoid over-watering. Frequent watering (every day or two) on flat or poorly drained ground, and/or heavy clay soils spells major trouble for your madrone. While some individual trees may do reasonably well in these situations, the risk of developing root disease is much higher. For those extended hot and dry summers, it is best to water deeply every few weeks underneath the drip line of the tree and away from the trunk. The best prescription for Pacific madrone health is full sun, not too much water and avoiding trunk damage.
Steve Bowers is the Forestry Extension agent for OSU Extension Service of Douglas County. He can be reached by e-mail at steve.bowers@oregonstate.edu or by phone at 541-672-4461.
There are three major groups of diseases that affect madrone: foliage diseases, branch dieback and trunk canker diseases, and, lastly, root diseases.
More than a dozen fungal organisms can cause leaf spots and dead regions on the leaves. These diseases may result in unsightly foliage and usually are not serious. What should you do? Pruning dead branches and raking fallen leaves before the fall rains may help diminish the spread of spores and infection to new leaves.
As for twig dieback and trunk cankers, these diseases are caused by fungi that kill the cambium (the growth layer inside the bark). Initially, the bark looks discolored, then peels off and reveals blackened, cracked wood that almost looks like it's been burned. Madrone twig dieback starts at the branch tips and is associated with drought. Madrone canker occurs on the main trunk or major branches and sometimes on smaller twigs. It usually develops after bark injury, causing cankers to grow around the trunk or branch, which may girdle and kill it. Oftentimes, twig dieback and trunk cankers are present on the same tree. Affected trees may decline rapidly and die in a year or two, but healthier trees may live several years or even decades. Again, what to do? Deep watering may help prevent twig dieback as well as minimize bark injury.
Third on the list are roots and tree trunk diseases. Cankers are usually located near the base of the tree, with a loss of foliage and small, curled leaves being common symptoms. Persistent, moist soil conditions favor the fungus, so trees growing in poorly drained soils are most susceptible. But what do we do?
The main way to avoid root disease problems for trees in your yard is to avoid over-watering. Frequent watering (every day or two) on flat or poorly drained ground, and/or heavy clay soils spells major trouble for your madrone. While some individual trees may do reasonably well in these situations, the risk of developing root disease is much higher. For those extended hot and dry summers, it is best to water deeply every few weeks underneath the drip line of the tree and away from the trunk. The best prescription for Pacific madrone health is full sun, not too much water and avoiding trunk damage.
Steve Bowers is the Forestry Extension agent for OSU Extension Service of Douglas County. He can be reached by e-mail at steve.bowers@oregonstate.edu or by phone at 541-672-4461.
