Re: best trees for lally columns
What Phil said.
I'd add that there is a significant difference between old-growth and second-growth cedar even within the same species. Second-growth isn't nearly as rot resistant or strong as old-growth cedar. Where you might get by without preservatives on old-growth, they are a necessity with second-growth.
Also, every species of tree has two types of wood:
- Heartwood -- in the center of the tree; this is the "old" wood that has hardened and doesn't contribute much to the life of the tree. It is naturally stronger and more rot-resistant.
- Sapwood -- toward the outer rings of the tree; this is the "young" wood which carries sap to the living parts of the tree. It is softer; more likely to warp, crack, and check; and has poor rot resistance. It isn't nearly as strong as heartwood.
In most species, sapwood and heartwood are different shades (lighter/darker). Generally speaking, the tighter the grain, the stronger the wood. For each "ring", there is summer wood and winter wood. The winter wood is harder and darker and more rot-resistant; summer wood is softer and whiter, and usually wider. Part of what makes old-growth better is that the ratio of summer wood to winter wood is lower, so the percentage of hard, strong winter wood is higher. Dense forest canopies and competition for nutrients is what causes "old growth" to grow slower in the summer than second-growth, yielding the tighter grain.
Last edited by Fencepost; 08-07-2014 at 12:53 PM.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.