Pruning Logs for Lumber

Reader Contribution by David Boyt
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We’re finally getting a good hard rain, and things are really greening up–most appropriate for St. Patrick’s day.  It seems like I’m always running way behind where I should be on taking care of trees.  They’re like children– they grow so slowly you scarcely notice, until suddenly, you’re grandpa!  Not only does my son have a toddler and a crawler, but the walnut trees I planted when we first moved here thirty years ago are producing nuts and sprouting up saplings of their own.  So grow my family tree, and my family’s trees.

I was going to try to prune at least 1,000 young walnut trees this year, but have managed only about 100 that so far, which is a shame.  It is one of the most pleasant jobs on a tree farm.  The trees manage to continue growing without pruning, and with no set deadline, my attention usually shifts toward more pressing matters.  I have about another three weeks before they break dormancy.  I can prune them while they are actively growing, but the risk of fungal attack on the open wound is greater, and I avoid it, when I can.  Besides, by then, I’ll have brush hogging, gardening, and, of course sawmilling to do.

Pruning, to me, is a quiet, thoughtful process.  I seldom resort to a chain saw, relying instead on a few hand tools.  Most versatile is the pole saw for high branches.  It cuts quickly, and gives my arms and shoulders a good workout.  The hand saw is good for the lower branches and has a very aggressive cut.  A pair of loppers makes quick work of the smaller branches.  All my pruning tools together cost less than $200.  Pruning trees for lumber is a different from fruit or nut trees.  Of course there will still be plenty of walnuts to plant and eat, even when the trees are managed for lumber.  With a decent walnut tree worth around $1,500 and exceptional trees several times that, the fifteen minutes spent now to get a young tree to that point in the next 100 years is a small investment.  What if I could manage just fifty trees per year and the next owners (hopefully my own “saplings”) continue the tradition?  Ice storms, tornados, fire, disease, and even family situations can make it a risky investment, especially over the span of a century.  Still, I can imagine few things I’d rather be doing.  What would the payoff be, say, for whacking a little ball around a golf course, or spending the day in front of a 50″ television watching football?

Pruning trees for lumber starts at the top.  The first thing to look at is the leader.  If it is forked and I can reach it with a pruning saw, I’ll remove the weaker or more crooked side of the fork.  The idea is to shape the tree as straight as possible.  It is amazing how a tree will straighten itself out after pruning.  Large low branches come off next.  The “rule of thumb” is that low branches larger than my thumb come off.  Branches that grow at a sharp angle to the stem also need pruning.  They are weaker and more susceptible to breaking off in an ice storm, and can strip the bark down along the trunk as they go.  Removing other branches can help straighten the tree.  Experts advise leaving at least 30% of the branches, but I often take off more than that.  It does slow down the growth for a few years, but it may be five years before I get back to a given tree.



The biggest mistake most people make when pruning a tree is cutting the branch of flush with the stem.  This does two things.  First it means that the tree has a larger area to heal over, and more chance for disease to enter.  Second, it can stimulate growth of another branch that you’ll have to come back and prune later.  There is a “collar” where the branch flares out next to the tree.  The idea is to cut just outside the collar at an angle to the stem.  You can do a lot of damage to a tree if the branch strips off bark when it falls.  When possible, I hold the branch to support it as it comes off, make an undercut with the saw, or cut a heavy branch several inches from the tree, then make a second cut just above the root collar.  If you do it correctly, the tree will heal in a few years, leaving a “cat face” like the one I’m pointing to in the photo above.  In ten years, even this trace of pruning will disappear.  Trees are incredibly resilient, so taking off a “wrong” branch isn’t a huge issue.  Walnut trees are prolific sprouters.  If I come across one that is just too crooked to ever make a good tree, I just cut it off a couple inches above the ground, and let it sprout back a good straight stem.  This is called “coppicing”.  With a good strong root system already in the ground, the new stem grows quickly, as long as I don’t hit it with the mower.  With the sawmill, I have a constant supply of stakes for marking trees.

Although I doubt I’ll ever mill any wood from trees that I planted myself, it does give me a sense of bringing things full circle.  Around these parts, people still save on posts by simply stringing fence wire from tree to tree.  While this makes sense at the time, repeated encounters with nails, staples, fence wire, and even ceramic insulators make cutting the wood from these trees a difficult and frustrating task.  Often the fence itself is long gone, and the tree has grown around the wire, hiding it entirely.  Still, I couldn’t resist milling up a good walnut log that came from a yard but obviously had wire hanging from it.  I ordered some bi-metal blades from Norwood.  They are specially designed to cut through wire without damage.  I cut through more than fifty strands of fence wire in that log, and the blade was still cutting fine, when it stalled on a 3/8″ bolt embedded in the wood.  The dark swirls of grain that grew around the wood look like ocean waves.  There is enough wood for several table tops, or a good-size table and several benches.

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