Last week I was in California speaking at a conference of the Western Chapter International Society of Arboriculture, including urban foresters, botanists, wood workers, and lovers of wood. I was speaking about my experiences harvesting wood on our farm and how that wood ends up in the furniture I design and build. Following the conference I led 20 people in building small tables, all from local urban wood.
We learned about the nitty gritty of how trees grow, and the different cell structures of hard and soft woods. Finally I understand the scientific basis for why quarter sawn lumber is more stable than flat sawn and moves half as much — because of the ray cells. They run radially from the heart of the tree to the outside and act like steel reinforcing. It's the exposed ray cells that shimmer on quatersawn faces .
Naturally figured woods were talked about, and the question came up about how birdseye maple comes about. In my experience the birdseyes can be dense in one part of a perfect log, and then dissipate away. No one yet understands why they form. One theory is the tree gets damaged and lots of dormant buds form but never sprout. But birdseye logs rarely show such damage, or any bark imperfections at all!
This is the first half of the talk I gave.
Nearly every aspect of my life connects to trees and wood. Primarily I am a furniture designer and maker and have been for over 40 years. I’m also a teacher, teaching all over the world about hand tools and techniques. For almost 25 years I have been a contributing editor at Fine Woodworking magazine writing about design and technique, along with 2 books about indispensable hand tools.
We live on a small farm in Vermont with about 13 acres of productive forest. From it has come much of the wood to build our house, and nearly all the wood for 2 barns, and my brick shop (it has a heavy wooden structure and wood roof, floors and ceilings). Our forest supplies us with the fuelwood that keeps us warm and cooks some of our food, fenceposts, habitat for wild turkeys, bobcats, and bear, and maybe most importantly tranquility during my almost daily walk among the trees. I once imagined I knew every tree in our forest.
For 37 years I have been harvesting, milling, and drying wood for my furniture. While not all of what I use comes directly from our forest, a great deal does, and much of the rest is local. We grow over 20 species of good hard and soft woods — oak, ashes, maples (some of the best hard or sugar maple in the world I am told), cherry, birches, aspen, butternut, beech, basswood, white pine.
In an average year I harvest 2 - 3000 board feet of logs during the winter months. Some years it has been closer to 5,000, which is a lot of wood — a good start on a modest sized barn. I fell trees in the winter when the woods are more open and accessible. Snow cushions the fall of good logs (that can suffer damaging shock cracks if dropped too hard) and makes moving them easier and cleaner. Clean logs make clean lumber, and keeps my sawyer Don Lawrence happy. He arrives every spring with his portable Woodmiser sawmill. He can pull right up alongsidea log, roll it on, and saw it with a blade so thin hardly any wood is wasted. We’ve sawn 36” diameter butt logs that yielded board after board 21+ inches wide, but more often logs 14 - 24” in diameter. We saw a lot of 5/4 thick hardwood for furniture. It’s a useful dimension to mill to 1”, or resaw into 7/16” panels. We cut 6/4 for legs or heavier structural parts, and 8/4 for still heavier parts or for resewing into thinner parts. A variety of thicknesses to choose from is efficient and cuts down on waste. Building materials are anything from 1” boards to 2X4, 3X7, 6X6. We always saw for quality, for clear straight grained wood over wide flat sawn boards. And when it is worth it we turn and turn the log to get maximum quarter sawn boards, for their alluring fleck pattern, linear grain, and better stability.
Making your own lumber is not quick, nor is it easy. Green wet lumber is heavy. Each board needs to be carefully stacked and separated with 1”X1” stickers, in a place with lots of airflow. Spring is the ideal time for this with the air cool and dry, so there is less chance of molds that can start growing almost overnight. I air dry in stacks as long as I can, but always at least a year to the inch of thickness. After that lumber moves into the top of my shop or one of the barns and can be stacked without stickers. Typically I dry to somewhere around 11% moisture content outside, and to about 7 or 8% in my shop.
So let’s deal with the question of air dried vs kiln dried. Is one better? Kiln drying might slightly improve a board’s stability and does hasten the time from sawing to using it. It will set the sap on softwoods like white pine that can bleed resins. Still, I much prefer air dried wood. Putting a plane to it I can immediately feel the difference. The fibers are more elastic and flexible, so my shavings are fluffy and continuous. End grain cuts cleanly, not into tiny bits but real shavings. Even shavings and sawdust from my machines are bigger, less dusty, so healthier for me. Air dried wood steam bends with far more flexibility than kiln dried, and thin laminates flex better for cold bending — a process I use to produce curved elements for my furniture. Air dried lumber has richer color. Steaming walnut for instance, leaches out the subtle reds, purples, and browns (darkening the light sapwood).
And lastly air dried wood is stable. What exactly do I mean by “stable”? A stable part doesn't warp or change shape unexpectedly. Far more important than the inherent stability of the species — and they are all different — is using my experience to choose the best wood species for what I am making, and the best grain for my parts. Even grain, quatersawn or rift sawn, no knots or wild grain — this is what I look for. The dried boards tell you a lot, by how flat they are.
Some species have issues. These are the ones I avoid sawing and using because they can warp unpredictably. Beech is one that I love but don’t trust. Aspen is another, where some trees are exceptional and the rest yield boards that warp into shapes you might use to plank a boat. Warp is the result of uneven shrinkage or stress, which all goes back to the tree and the way it grew. Each board mirrors that tree, from curving grain lines due to a gentle bend of the trunk, to knots, uneven growth, or some other anomaly.
Wood will likely warp in some way as it dries from green (wet) to equilibrium to where it lives (8%?), be it a dry climate or a wet one. Wood never stops absorbing or giving up moisture, and changing shape. Some woods have cell structures that give them high stability, such as mahogany or walnut. It’s no mystery why so much of the highest style antique furniture made here and in England was made from mahogany, and to a lesser extent walnut, only some from cherry, and little out of curly maple, a less stable species. Of course mahogany and walnut are handsome, but they are also exceptionally stable, and in mahogany’s case, once came in boards 2 - 5’ wide.
PART 2 further explains the advantages of sawing your own lumber, and woods that I especially love and why.