It's true that old-growth wood is stronger and denser than modern wood, but it's absolutely not true that obsolete windows made of old-growth wood are better than modern windows or should be retained in a restoration if not required by code. Wood is a terrible material to make window frames out of, and there's simply nothing you can do to a single-glazed window that makes it comfortable to live with.

We have this thing called "building science" now, you can do better than just copying your grandpa.

A company called Invent Wood (based on research out of UMD) is creating “densified” wood that solves a lot of these problems. They have a process that collapses the cell walls in wood and compresses it to a quarter of its thickness, which gives something like a 10x increase in tensile strength, making it stronger than (a certain type of commonly used) steel by volume and weight. It’s also significantly harder than wood (nearly as hard as the carbon steel people use for knives), doesn’t warp, and is resilient to impacts.

My intuition is that trees need wood to serve purposes greater than just structural integrity. It needs to transport water and nutrients. But for building, we don’t care about these channels and it’s better if we collapse them to encourage stronger hydrogen bonding between cellulose chains.

It sounds like a lot of the benefits of “old growth” wood can be manufactured now. This is probably a good thing for preserving nature; there’s a greater demand for wood with these properties than a supply of old trees. Better to leave the great old trees intact and do cool engineering on cheap trees that grow quickly.

Recent Hacker News discussion:

https://news.ycombinator.com/item?id=44020832

I've lost many a titanium drill bit to old growth wood in my 1921 home. Insanely difficult and hard stuff. It's crazy that we consider it the same material.

You also have to remember that new 2x4s are actually 1.5x3.5 while older ones were actually 2x4! Its fun to do work on an old house and actually get the correct measurement of 2x4 xD