"The Brain" the wrote in message
...
Tough Guy no. 1265 wrote:
Ever seen inside a knot? I accidentally discovered this while
demolishing:

https://www.dropbox.com/s/2tj1znjs37....jpg?dl=0&s=sl


That's a dead knot. The branch died off but remained
attached to the tree and subsequent rings on the trunk
grew around it. Basically its no longer attached to
the subsequent growth and so can be knocked out of
the plank. And so is a source of structural weakness.

Had it been sawn off next to the trunk before it died
off then there would have been a tight or live knot
inside the trunk which would be revealed when the
trunk was sawn. While its of a harder consistency
it's part of the growth and unlike dead knots
doesn't weaken the timber.



michael adams

....