What Could Go Wrong? Beware Dead Trees

Bark beetles killed this pine just this spring. My intention was to fell it against its lean, but the tree had another idea. I learned how quickly the fiber in dead pines deteriorates.

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We leave bug-killed trees as wildlife snags, generally. They fall within a couple of years and become ground logs, the bottom of the food chain. But when dead trees are close to roads or structures they pose a hazard. In this case, 2 trees on either side of a road died of pine beetle infestations, and one taught me a lesson.

I wanted to drop this 11” Ponderosa pine uphill, away from the road, where I could come back later to skid it out. The tree had a slight lean downhill. There were no hazards in either direction, and I had 360° of escape routes – it was just a matter of convenience to throw the tree uphill.

No problem. The tree was green just a few months ago, before the beetle eggs under its bark hatched and killed it. It should still have good fiber for a hinge. What could go wrong?

This fall would require a wedge. There’s not much room for a wedge in these small-diameter pines. I bored the tree two directions: from side to side to set the hinge; and front to back for the wedge. (I have a video in the works showing this technique for felling leaners where the DBH is less than the length of a felling wedge.) My hinge was about 1.5 inches thick, and 3-4 inches remained on either side of the wedge.

As I was hammering the wedge I saw a tiny but unexpected movement in the tree. I stepped back to watch the tree twist on its stump and fall in the direction of its lean. What happened?

This technique of boring through the face cut allows the use of
a wedge in small-diameter back leaners.

The fiber was brittle in the outer 10 growth rings, where the strength of the hinge typically comes from. The wedge jacked up the tree and broke the hinge loose on one side.

The tree, now connected only by about 5 square inches of hinge on the other side, twisted and fell. The remaining hinge tore out of the stump.

Maybe boring through the hinge was a mistake, and that extra 1/3 of the hinge would have kept the tree on target. Maybe the relief cut under the wedge was too small -- having a wedge lifting directly under the hinge is what broke the already-weak fiber. The heartwood was blue, which comes from a fungus, I believe. It’s hard to say whether there was enough strength in that center fiber to prevent the hinge from failing anyway.

The lesson was that I don’t have many weeks between the time a tree dies and the time when it can no longer be safely coaxed to fall against its lean. That doesn’t mean they can’t be felled safely.

A week later I was cutting some beetle killed trees for my neighbor. I dropped them all toward their favor, within 15°. They all went down without incident, right where I aimed them.

The strongest parts of the hinge had already decayed.

This side of the hinge ripped out of the stump as the tree fell.

When felling dead trees, be ready for anything.