Q. Dear Pete: My wife and I planted vine maples along the east and west sides of our home in 2003. We are unable to comprehend why the leaves of two of three trees are turning orange prematurely (before fall). Is there some way to determine if they are suffering disease or simply individuating (like teenage children)? The photos attached show: Two vine maples are on the east side of the house. The southernmost tree is orange. The northernmost tree appears green and healthy. The third tree, on the west side of the house, isn’t very leafy and what few leaves it has are orange. Do trees have receding foreheads? I don’t know how to discriminate soil-based issue vs. fungus vs. disease. I’d like to keep these trees. Any ideas? Thanks for your prompt response. Sincerely, Charles Mann – Tacoma, WA
A. I am sorry to say that Jung won’t apply in this case because your Vine Maples (Acer circinatum) are not individuating but rather indicating. But without some detailed observation it is difficult to say what problem is being indicated. The general term for what you are describing is called Maple Decline. There is some detective work that goes into the diagnosis and I can give you some clues as to how to narrow it down. You may be best served hiring a professional certified arborist to verify the problem. The first thing to consider is drought. These plants trees prefer moist soil especially if they are in full sun. They can get by with less soil moisture when they are shaded. If the all three trees are getting adequate water during our dry summer then the next possibility is root girdling. Root girdling can occur if the trees were grown too long in a small container the roots being to wrap around the sidewalls. If these roots are not pulled apart, scored (slicing outside of root ball with a knife) or otherwise manipulated out of this pattern they will continue to circle and enlarge. Over time this will slowly “choke” the tree to death. The way to check this is to slowly excavate (think like an archeologist) soil away from the base of the tree for several inches. You can use some water from a spray bottle to help clean away soil for a better view of the roots. At this time you can also be looking for signs of disease. Start from the trunk and work your way down to the exposed roots looking for loose bark, cracks or fissures, discoloration, oozing. This would indicate a collar rot / basal canker which is a fungal disease. If you find girdling roots consult a certified arborist to see if it is feasible too surgically remove the offending root(s). If you see symptoms of disease there is currently not a cure but there are measures you can take to help the tree fight this off. One is leaving the base and root collar (where the main roots meet the trunk) exposed so that the base of the tree stays dry. Keep the trees well watered periods of low rainfall. Other causes of maple decline can be physical injury from a lawn mower or string trimmer, herbicide injury, or soil fertility problems to name a few. Again a certified arborist is trained to narrow down the possibilities systematically.