Gentlemen,
I am sure you have heard someone say, "prices keep going up and the quality keeps going down". Well, this is really true in the timber industry.
When I spoke about knots and dry rot and such, I was refering to them in laymen terms. To a laymen, a knot is a knot is a knot and dry rot is dry rot. This is not always the case.
A knot is normally caused by the grouth of a branch/limb or seperation of the tree trunk. Through these limbs, branches and trunk, flow the life blood of the tree, sap/resions. Sometimes, more often now than before, during the grouth of the tree, vines will grow around the trunk and high into the branches. Some people think that this has a really nice look to it. Keep in mind that I am refering to trees that are used most in the building trade such as cedar, redwood, pine, fir and dougfir. What happens when these vines start growing around the tree is that they start to choke off the life blood flowing through the trunk, branches and limbs. The internal cells of the tree will not get the sap and resions that it needs to live on therefore creating what a lot of people refer to as dry rot in the heart of the tree. I have seen pines, cedars and redwoods over 200 feet tall with the inside or heart completely gone because of this. In high winds, these trees can snap like tooth picks.
When these trees are cut and milled, the knots have already started to decay because they could not get the natural resions they needed to survive on. These knots will be soft and porous. If you go to the lumber yard and look around, you'll see what I'm talking about. If your a good contractor, you'll discard any boards with this type of knot.
Now, the term "dry rot". Dry rot to a laymen means rotted wood caused by the elements. Here again, this is not really a true and complete statement. A lot of "rot" can occure while the tree is still growing. This is refered to as root desease. Root desease can cause grey rot, red rot, pink rot, blue rot and a few other rots. These different rots get their name from the minerals in the ground that the tree is growing in. Once the root has been damaged, it will absorb the minerals and create the different color rots. It's an infection much like we can get if we get cut or scratched.
The ones that we run into the most is the grey and blue rot. You will find these on a lot of log homes. If you cut a section off a log and look at the butt end, you may see a pie shape discoloration of blue or grey. If you count the life rings down to the pointed end of the pie, you'll be able to tell when the tree was effected during it's grouth. These discolored areas will be a little softer than the rest of the wood because they were not getting all the saps and resions they needed.
Well, I could go on and on about this subject but I have other work to do. Anyone can put a band aid on but this dosn't make them a Doctor. Cleaning and sealing a piece of wood does not make a Wood Restoration Expert.
Have a great day.
Jim Bilyeu,
Exterior Woodcare