What is causing the white pines to turn brown in my neighborhood?
I have noticed that many white pines in my neighborhood are turning brown. They are not near traffic (so not salt) and are very old white pines. What may be causing this? They are turning completely brown, not just dropping seasonal needles.
Viña Lindley, Food Systems & Home Horticulture Professional
Thank you for your question. Your observation about the white pines in your neighborhood suffering premature needle loss is, unfortunately, an issue that we’ve been hearing about from many parts of the state. According to the Maine Forest Service, the damage is likely caused by white pine needle damage disease complex (WPND) and results in pine needles prematurely turning brown and dropping off otherwise healthy trees. As the name suggests, there are four different organisms causing the damage. The conditions that favor their establishment are prolonged periods of wet weather in the spring during the time that the pines needles are elongating. The symptoms don’t present until the following year, which helps explain why we’re seeing so much damage but haven’t had a wet spring. The spore-producing structures erupt from infected needles the year after they initially become established, which then infect the current year’s new growth and the cycle keeps repeating. It is possible that the on-going drought conditions are actually making things worse, because the trees are generally less able to combat disease pressures when they are also stressed by lack of water. The good news is that if there are green tips and candles the tree/s will survive and produce more needles but it will look thin and wispy for this season. If the tree/s are not showing signs of new growth then, in all likelihood, they will not survive. While fungicidal application is an option it would probably be impractical to try to apply a fungicide in very large, old trees.
Here is a fact sheet about WPND for more information.