Why are the pine needles turning yellow and dropping in my area?


Many of my pine trees and many others in the area have turned unusually yellow and are dropping huge amounts of needles. I don’t remember ever seeing it this bad. Is this something I need to be concerned about?


Jonathan Foster, Home Horticulture Outreach Professional

There are numerous reasons why a white pine might brown or lose needles, both biotic (i.e., pests or pathogens) and abiotic (i.e., environmental). Road salt from winter is a common culprit, and you can often see its effects alongside major thoroughfares like I-95. Environmental conditions that promote relatively warm area above frozen ground can also dehydrate coniferous trees, which remain metabolically active a lot rate through the winter months–they can lose water through their needles without being able to replenish it from the hard ground below. This is happening more often with our increasingly volatile winter temperatures.

However, another likely culprit is something termed white pine needle disease complex, a major problem for white pines across New England. It’s a suite of multiple pathogens whose success is being driven by our warming climate here in Maine–you can read more about it on the UMass-Amherst Extension page “Dieback of Eastern White Pine.” The Maine Forest Service is aware of this issue and might be able to offer more advice on managing larger number of pines that are being affected–you can contact them here. If it’s a smaller number of trees on your property, I recommend contacting a ME-licensed arborist to see if a fungicide treatment would be appropriate.

There is some indication that trees are beginning to adapt to the situation by increasing photosynthetic rates in surviving needles and storing carbon resources in lieu of vigorous growth. But at the moment, WPND remains a major concern for Maine gardeners and landowners.

I’m sorry not to have more positive news to share, but I wish you happy gardening, nonetheless.