Lumber Stress in "Fence-Row" Trees

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Cherry trees growing on a fence-line may have lumber stress (and interesting grain) March 14, 2005

What built-in stresses can be expected in a single row of trees grown along a fence? I have 65 acres of timber (cherry, oak, maple ash, etc.) in large stands on a farm in Ohio that I plan to selective harvest to improve the stand (by thinning and removing over–mature and damaged trees) over the next few years. I have sought the advice of our local state forester in developing my harvesting plan. I plan to cut the trees, pull the logs out to a landing site, pay a local portable sawmill to cut the logs into boards, and deliver the lumber to a local kiln to maximize my return on this resource.

My concern is for several large cherry trees that are growing along some of the fields. I was told that sometimes trees not grown in a stand, such as those growing along fence lines, do not benefit from the density where the masts may be smaller, the tree packing tighter, and rapid vertical growth due to the competition for sunlight. Fence line trees are subjected to the full brunt of wind and weather. These trees grow in all directions, with limbs at all levels, rather than shooting for the sky, and that exacerbates the effect of the wind and weather further.

I was told that stresses can develop within the wood under these conditions that make drying and use more challenging. The fence line trees vary from saplings to over 40 inches in diameter and with heights in excess of 80 feet. Should I assume that all of this is blocking material or firewood? Can I make an assessment during harvest? (I am aware of the fencing impacts and the possible presence of metal for the first 8 to 10 feet with regard to the sawing operations and safety.) Even if dried properly, can this wood distort more than normal later if used for furniture or cabinetry? Maybe the opposite is possible. Since these trees have been stressed more than typical trees, the built-in strain compensates for the stresses.

Do you have any thoughts on this matter? When I see a building expansion or new development underway, and the cleared trees are hauled off to a dump, I think it is a terrible loss. I would like to ask the owner for these trees and turn them into useful boards. But if these trees are less useable, only suitable for firewood, then I will look at this issue in a different light (fireplace light).

Forum Responses
(Value Added Wood Processing Forum)
From contributor F:
You have been advised correctly regarding open grown trees. They will tend to have a good deal more stress than stand trees. They will, however, have a good deal more interesting grain than stand trees. Don't pass up the opportunity to really cash in on what may be some beautiful turning wood. Some of those crotches will yield magnificent pieces of wood! If you do decide to plank the wood in these trees, just make the planks thick (or make cants) so they can be resawn after they cure out for a considerable time. You may want to wax the ends of the prime stuff so they don't check badly. Don't use for firewood!

From contributor J:
The grown-in tree stresses are usually found in trees that are growing on slopes. Crooked stems show compression wood on the lower side of a log and tension wood on the other side (upslope side). Wider rings are on the lower side. Cutting boards from these types of logs will cause the boards to splay out, making a crooked board as the saw opens the cut. These crooked boards are very useful to a cabinetmaker who makes chair legs and rocking chair rockers. Lightning strikes and tornados can also play havoc to a tree by causing broken hearts and splits and lengthwise cracks (shakes), some of which may be unseen until you open the log. You are wise to get the services of a professional forester to help you with your woodlot questions.

From contributor F:
Here in the Northwest, most all trees grow on slopes. Growing on slopes has little to do with inherent stresses under normal site conditions (classes). If that was the case, all lumber sawn here would be stressed. It is not. Larger growth rings occur, typically, on the backside of the stem, away from the sun (where the growth is faster), since the sun inhibits growth proportionally. This is why a stem will grow toward the sun. The sun inhibits the growth on the front side and the back side grows faster, bending the stem toward the light source, hence, larger growth rings on the backside. Open grown stems are stressed primarily due to the larger limbs that do not die off to lack of sunlight as they would if grown in a stand. Large, open grown stems such as those found in pastures, along fence lines, etc. produce some spectacular patterns in their woods.