What is killing our white pine trees?


I am looking for some help identifying what is killing our white pines trees.

The disease is spreading slowly from tree to tree, but once infected it seems to only take 1 or 2 seasons to completely kill a tree.

The trees appear to be rotting from the inside out. The trees needles turn yellow, then brown, and fall off. The bark then starts to fall off the trunks. When we cut the trees down, the insides are rotted out.

The arborist we had to help remove some of the dying trees from around the cabin wasn't able to identify the disease; and none of the common white pine diseases I googled seem to match the symptons.

I've attached some pictures of some infected trees. Any suggestions or recommendations would be appreciated.


These two trees were alive and well in April.
20170905_143010.jpg 20170905_142441.jpg 20170905_142341.jpg


Well-Known Member
I'm seeing some blue stain fungi in the sapwood which is indicitive of conifer bark beetles. Pine sawyer beetles introducing pine wood nematodes may be another coffin nail. The interior decay is a brown cubical rot type fungi and is indicitive of much earlier wounding and decay introduction.

When you get into borers and bark beetles, you need to investigate long term weather and environmental factors as well as site conditions and any previous construction type work done near the trees. In short, you should consider what factor(s) affected the tree and resulted in enough stress to weaken the tree to the point where the insects became attracted to the trees.
Hi JD3000.

Thank you for the response. I will do some research on the beetles.

In terms of stressers, the trees are located on the south end of an island and are quite secluded. We haven't done any construction. However, we just went through two very dry growing seasons which might have triggered some stress in the trees. The trees on the north end are all healthy and fine and would have undergone the same weather. Its very alarming to see dying trees spread slowly across the land.

If you think of any other possible causes of stress please let me know!

Thanks again



Well-Known Member
Hmmm south side is exposed to more direct sunlight and would dry out faster than the north especially when weather has been dry.
Hi JD3000

The island is 1.25 hectares, so I think some do get a lot of exposure, but it is still heavily forested and most of the south end is somewhat protected by other trees. But it may have started on a single pine and spread from there.

I looked up some information on the beetles. It looks like the dry weather plus the presence of sawyer beetles (I've seen the beetle larva while cutting up the trees) points to pine wilt. However, some websites say that white pines are not susceptible to pine wilt.

They say pitch pines are susceptible, but we have lots of those and they are currently enjoying the extra sunlight from the dying white pines.

Is it possible we have a nematoad strain that prefers the white pines?

I'm heading out there tonight and will be back to civilization on Monday. I will check for more signs of pine wilt or other sources of a potential stressor that might be attracting the beetles.

Hopefully the heavy rainfall we had this year will give the healthy pines the strength to fight off any morw infections.

Thanks again for the help, now I have some direction to go in.



Well-Known Member
white pine is resistant to Bursaphelenchus xylophilus, not immune.

And don't disregard the bark beetles. The blue stain is usually diagnostic of their presence. Turns out nematodes can also feed on blue stain fungi in pine wood as well.
It's a sick sad world.