Thread: Read Wood Grains

Originally Posted by justonething

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1. The direction of the wood grain of a tree trunk is from the bottom to the top of the trunk;
2. The direction of the wood grain is from the outer growth rings to inner growth rings;
3. The direction of the wood grain around a knot is from the outside rings towards the centre of the knot;

Are these observations correct?

Can't argue with those statements. In simplistic terms, a tree trunk is just a cylinder of little pipes (the vessels that carry sap up & down) stuck together with glue (lignin). The pipes try to run straight up & down, but have to duck & dive a bit around any obstacles like dead knots (which successive growth eventually cover over) & into branches, but essentially they run from the roots to the branch tips continuiously. Each growing season, a new layer of cells is laid down all around the trunk - the only living cells capable of reproducing themselves are out there in a very thin layer that makes bark on one side & "wood" on the other. Various factors cause uneven laying down of cells, or cause them to align a bit differently in successive seasons forming rowed grain (which is often the most difficult to read), curly grain, or all sorts of other weird effects.

I find the best way to 'read' a typical flat-sawn board is to look at the edge. In most woods you can easily see if the grain is parallel to the face, or if it is rising towards one face or the other. It's most obvious when the edge is somewhere close to matching a radial cut, but it's usually easy enough to see. Not uncommonly, the grain goes one way at the beginning, then the opposite way 3 or 4 hundred mm further along, then switches back again, so no matter which way you plane, you'll be planing 'uphill' or 'into' the grain (among the various terms the old blokes I knew used) for part or parts of your stroke. That's when you'll be thankful you learned to sharpen well & set a tight cap-iron....

Cheers,