What Makes A Good Crotch?
When I cut wood, I am always on the lookout for the unique. I don’t always know what I am going to find, but I know that the less it looks like wood or “regular” wood the easier it is to sell. And, even though I like to cut anything and everything wood, it just makes good sense to cut the stuff that sells. Often the lumber goes up in value because of things that happen to it after it is dead, like spalting and bug intrusions, but a lot of good things happen when the tree is alive and growing too, like burls and curly figure. I guarantee, if I ever cut a curly log, with burls, that is spalted and full of bugs, that it will sell – quickly and at a good price (for me, that is).
Every log has wood in it somewhere that is at least a little irregular. You just need to know where to look. One place that holds a lot of promise is the crotch area, another is the stump and a third is at the base of large branches.
All of these areas have one thing in common – None are regular, plain, or straight-grained. Some are better than others, but none are regular. They stand out because the grain is figured, usually referred to as curly (at least by me). The curliness happens when two directions of wood grow into each other. It is a little hard to explain, but easy to see, especially in a crotch.
A crotch is an area on a tree where a single trunk splits into two, forming a “Y” shape or an upside-down pair of legs, similar to your own crotch. In this magical area, the tree is short on space for the material that is added to the tree as it grows. With each year of growth and the addition of another annual ring of thickness, things get crowded. Wood pushes against wood and the grain starts to buckle in different directions. It shimmers in the light and looks like waves of liquid. The crotch, in particular, can be large and somewhat predictable. If the crotch is built well, the wood inside will be worth the work.
Notice I said, “If it is built well” – not all crotches are. The good news is that usually everything you need to know about the inside of the crotch is labeled on the outside. You just need to be able to read it. Here are a few keys to the language:
1. Bigger is better. The bigger and wider the crotch, the bigger and wider the figured wood. Wider crotches are also longer. Every ring of growth adds to the width, but also pushes the crotch up, adding to the length.
2. Pointed isn’t the best. Between the two branches, at their intersection, things should be rounded, not pointed. Round inside curves show that the crotch is increasing in length every year as one piece and not two pieces crashing into each other. I like to think of a really good crotch as being “U”-shaped as compared to “Y” or “V”-shaped. A truly “U”-shaped crotch is difficult to find.
3. Parallel is worse. If the branches that meet to form the crotch are close to parallel, the crotch will be long, but broken into two separate pieces. Bark from each branch gets forced into the wood as the crotch grows over it. A 90 degree angle between the two branches is ideal. Think perpendicular, not parallel. Parallel is just two branches growing next to each other, not a crotch.
4. Bulges are the worst. If a crotch is forming correctly, with no bark inclusions, the crotch itself will be flat on the outside where the branches meet. A bad crotch will have a bulge, indicating that the crotch has bark in it (bark inclusion) and the tree had trouble growing over it. It may look like one solid piece on the outside, but the inside will be divided into two pieces with bark down the middle (not exactly what you are looking for in a crotch).
Besides the size, all of the other concerns above (#2 through #4) are regarding bark inclusions (which we are trying to avoid). Without bark inclusions, crotches are a single piece of highly-figured wood. With long bark inclusions, the crotch is usually unimpressive, not figured and broken.
For most of you, deciding how or whether to mill a crotch will never be an issue. At the same time, I have run into plenty of people who want to have logs milled and are especially excited about a crotch section that just won’t pan out. If you find yourself trying to decide how to cut up a tree with a crotch in it, I hope this proves to be helpful. Notice how I gently worded that and didn’t say, “Don’t mill it.” I would never say that.