Red Pine Needles Turning brown/red only at their tips

Asked July 2, 2015, 8:40 PM EDT

We live in North Eastern Ontario and have a roughly 5 acre, 30 year old pine plantation. Until this year there has been no issue whatsoever with tree health and vigour. We take the dog for a walk through this plantation every day and recently, we've noticed that a large number of trees are half green/half red. These trees are randomly spread throughout the plantation and appear to have to pattern or reason. Red trees exist surrounded by perfectly healthy looking trees (in close proximity) and there are also some that are in clumps. The trees in question appear to be growing as good as the ones unaffected. White pine also exist in the plantation (although fewer in number) and none appear to have the same affliction.
Its hard to imagine this being a fungal root infection because, I would think, that the all parts of the needles would turn red at the same time as opposed to only the top half. As well, this years growth would not be just as vigorous as ever?
We're worried that this is a problem that could spread to healthy trees and eventually kill the plantation or, weaken it to the point where bark beetles may move in. Any help/suggestions as to what it may be or what to do would be appreciated.
I should mention that over the last 2 years we have thinned the stand twice. both times in December and we have always removed all slash and taken bark off logs. We have been careful to not introduce anything. But its possible we've failed somehow.

Outside United States trees and shrubs canada pine trees horticulture

4 Responses

Dear gardener,

Thank you for contacting us. I am looking into your question, however it would be helpful if you would confirm the species of pine affected (red pine, etc.)

Dear gardener,

Please excuse my previous inquiry as I did not notice that you specified red pines in your title.

There are several fungal diseases that may be affecting your pines. To get a definitive diagnosis, you should consult with a certified arborist. It is also possible that your local conservation district may be able to offer advice given that you have some acreage.

There is no treatment available for most pests and diseases, and those that are available are restricted to authorized users in Ontario. Your practice of culling trees and branches is your best line of defense and treatment. The affected wood should be removed or burned if possible.

Thank you for your response Lynne.

I have more information that only causes the mystery to grow however. We did end up getting an Arborist to come look at the trees and his initial guess was a blight of some kind, which, as I understand it, is a fungal infection. However, he took a couple samples and sent them away for analysis at a University here in Ontario. The results came back as 'no fungus detected'. Apparently they were quite sure it was a fungus and tried hard to confirm that but to no avail. After which they inspected the samples further and said that they noticed 'small feeding tubes' under the bark of the branches but they couldn't confirm what it was as they were empty. It is important to note that the samples they were working with were, at most, a centimeter thick. Both the people in the lab, the Arborist, and myself do not know what this could be. Any ideas on your end?

Thank you in advance for your time.

Dear Gardener,

You've consulted with people that have more expertise in this area than I. Sometimes it comes down to treating the symptoms, especially when dealing with fungal diseases. There are so many, and often the weather is a big factor.

Treatment for most fungal diseases is the same, and sanitation is probably most important: Disinfect pruners after each and every cut. Remove any plant debris and destroy it rather than compost (bury or burn where possible.) And always use several inches of wood chips as a mulch within the drip line to prevent reinfection from rain splash.