Q. We have two birch trees in our backyard. Both were planted at the same time about eight years ago. Towards the end of summer, the tree behind the bird feeders started to turn yellow and the leaves dropped until now it is almost bare; the other one remains full of healthy green leaves. We are wondering if the bird feeders have anything to do with the dropping of the leaves or is there another explanation.
S. N. of Belleville
A. There are several reasons this could be happening. First, even though both trees are birch trees, they will have different genetics if grown from seed—unless they were both grafted from the same adult tree. Second, there could be differences in the soil chemically or in its soil structures, which may make one site drier and causing the tree to lose its leaves. Sunflower seeds found in birdseed mixes can cause certain herbaceous plants to die, but so far there is not any information of sunflower seeds having an effect on trees.
Q. I have a 40-year-old birch tree that lost its leaves in early September. Since then it has developed clusters of green leaves that look like oak leaves. I asked an arborist and he said he had not seen this before.
D. G. of Belleville
A. There is a birch dieback disease that was first noticed in 1932 in New Brunswick, Canada. It was caused by environmental changes, such as a sudden exposure to full sun, higher air and soil temperatures, lower relative humidity and higher wind velocity. Shallow rooting over time also proved to be another cause. There was one final flush of budding-out of leaves of the birch trees before the trees died. But no mention was made about a different shape of leaves such as oaks
The widespread outbreak of dieback was unrelated to logging or to any other human disturbance. Other Maritime Provinces in the East also experienced this phenomenon from 1920 to 1950 and this was thought to been caused by a rise of 1.0 to 1.4 degree Celsius with a climatic warming trend. This information on birch trees dieback was found in the book “Diseases of Trees and Shrubs,” published by Cornell University Press.
Things to do this week:
Rake or mulch leaves as most of the leaves have begun to fall to prevent dieback in lawn and turf grass areas.
Also prepare to gather mulch to place around the base of rosebushes after the soil has frozen solid to keep any thawing and heaving from occurring for the reminder of winter which could kill the plants.
Charles Giedeman is a local contributing writer. Send your gardening questions to Suzanne Boyle, Belleville News-Democrat, P.O. Box 427, 120 S. Illinois St., Belleville, IL 62222-0427, or email them to firstname.lastname@example.org.