Wood hardening?

Re: Wood hardening?

Bill Howatt

Short answer is I don't really know but the dryer the wood the harder it is.

Chipper a local dump handles certain diameter but they will only chip the wood at that diameter if it is not dry - dead is considered dry.

Bill

Re: Wood hardening?

Keith Newton

Here are a couple of things. Hardness of any wood is greater the drier it is, and softer when wet. As for the pine getting harder, I'm not sure about all of it, but from my experience doing some demolition of older structures, the pine up in the roof is probably harder than floor joist at the same age. Besides having a lower MC up in the heat of the attic, woods which have been exposed to high heat, especially for long periods become brash, which results in abrupt breaking, when otherwise you would expect more bending or flexibility.

Back to the Cherry, I don't have any answer for the cause of the less density, but from my observation, the lighter less dense will need a good wash-coat before staining to keep from being blotchy, where that with higher extractives within the cells is more forgiving. Some of the richest / darkest cherry that I've ever gotten was from pretty large urban trees which probably had more leaves than I would expect to see on a tree in a forest which is competing for light with it's neighbors.

I don't believe the premis

Bill Tindall, E.Tn.

I can not think of any chemical reaction that would harden wood with age. Possibly with pine the resin might harden with age but I don't regard resin as being very hard under any circumstance.

Re: Wood hardening?

John K Jordan

I have no idea of the reason, but I have a thick walnut board (maybe 3"x10") that came out of an old house. The guy who gave it to me said it was used as a mantel and he thought it was close to 100 years old. It is not only very hard but dulled a new Starrett 3/4" bi-metal bandsaw blade in just a few cuts.

Of course, it is unknown if the wood was that hard and abrasive when it was "young". But I've never worked any other walnut like it.

Also, of course, how hard it seems is a very subjective thing. The Wood Database puts the Janka Hardness of walnut at 1,010 lbf. If I knew how to rig up such a test I could compare. But again, whatever number I got would apply to just that piece of wood and prove nothing about if and how it changed. Someone would have to do a very long experiment to see if a given piece changed!

What Michael Dresdner said:

http://www.woodworkersjournal.com/age-make-wood-harder/

Deb Alden said it does:

https://www.bobvila.com/articles/463-the-beauty-of-reclaimed-lumber/

The only other Google hits I found give a variety of opinions on forums such as this one.

JKJ

Re: Wood hardening?

Barry Irby

As a Home Inspector near Richmond, Va I get to look at a lot of houses well over a century old. Did research on the methods and materials. Found studies that indicated structural lumber (pine) remained stable for about 75 years and then some change occurred allowing joists to sag and compress.

I would also think there would be some variation in density and hard ness with changes in growing conditions. Altitude, soil chemistry, shading, air pollution, etc, could all have effects.

Local cherry has lots of little "defects", dark dots and streaks. I "never" get a nice clear board. I am working my way through about two thousand feet we cut off the farm.

Re: Wood hardening?

Larry Clinton At Frankfort, (Central) Indiana

Personally I think the "old growth" wood is harder initially, due in fact to being from a denser woods. The forests where old growth trees grew were normally crowded and caused the trees to grow much more slowly therefore having very tight growth rings, therefore being both heavier and harder.

When I was a young lad I used to help cut firewood from my Aunt's woods in Northern Indiana. This was an old growth woods with about 90% Oak trees. This was also very poor soil (yellow sand). The trees grew quite close to each other and an 8" dia. tree often exceeded 50 years of age.

Most were very tall for diameter and straight due to fighting for sunlight. This was some of the heaviest and hardest domestic wood I have ever seen.

I am quite sure some of the same variety of oak grown in the open in good soil would have been at least 3 or 4 time larger in diameter.

The house I was born in was built from local oak with rough sawn lumber. When I had to nail into any of the structural lumber in the house I had to pre-drill every hole as it was impossible to drive a nail even when lubricated with wax.

I don't think the age of the lumber after sawing had any real effect beyond the drying, I think the wood was just very hard and dense to begin with, and today's lumber, mostly cut from second or third plantings is far less dense / hard as cut.

Backwards from my experience

Bill Tindall, E.Tn.

I used to work a lot of white oak. Lumber that had close rings was light and soft. I could easily nail it, even with finish nails. Makes perfect sense. "Spring wood" or "early wood" is the non porous wood made in the fast growth early part of the season. The width of this ring depends on how fast the trees is growing. This ring could be 1/4" or more in good growing conditions. This wood is dense/hard. Late wood is the porous part of the annual ring laid down late summer. It is about the same thickness regardless of growing conditions. The fraction of porous late wood in a slow growing tree will be much greater than in a tree that is growing rapidly.

The oak with the finish nail has about 16 rings per inch, very slow growth.

In my experience, for walnut, poplar and the oaks, rapidly growing trees produce wood that is more dense than deep forest slow growing trees. The difference is as great in a "field grown" poplar vs a "deep woods poplar" as it is in oak.

Not by my u-grad & grad classes

ebd

Botany/Plant Anatomy/Plant Physiology major.

Re: Backwards from my experience *LINK*

Larry Barrett

I agree with your general premise - fast growth produces stronger, heavier wood than slow growth, at least for hardwood. But I think you have the earlywood - latewood descriptions backwards. Early wood is usually quite porous, latewood quite dense.

See the Forest Products Lab Handbook, page 3-5 as an example.


https://www.fpl.fs.fed.us/documnts/fplgtr/fpl_gtr190.pdf

Bill that is exactly the opposite

Keith Newton

of what R Bruce Hoadley shows on the first page of chapter 1.

In a ring porous wood like Oak, the open pores are the Spring, or Earlywood, and more dense cells are Summer into Fall. There are no new cells added when the leaves are off. Thus a nice wet Summer like we're having here in AR at the present will produce a thicker layer of heavier more dense cells.

In softwoods like yellow pine, the soft portion of the ring is Spring or Earlywood, and the darker portion is the Latewood.

I stand corrected...

Bill Tindall, E.Tn.

thanks, but the conclusion remains the same.