Wood You Happen to Know?

I find it somehow ironic that the two trees that cause the most allergy-related grief in this country are also the ones whose wood is most commonly used for building. In my native Oregon houses are usually made of fir or spruce lumber. Here in Japan, however, the overwhelming majority use sugi (Japanese cedar, though it's actually related to the redwood) and/or hinoki (Japanese cypress).

I have discussed this issue (between sneezes) before, but the main reason sugi and hinoki are so prevalent in Japan is because of the post-war reconstruction effort. In fact, they were originally nowhere near as widespread as they are now, but virtually all of Japan's forests were logged into extinction from the closing months of WWII on account of a chronic shortage of wood. All of these were subsequently replanted with sugi and/or hinoki, partly because of their value as timber, but mainly because they grow so fast. However, though both trees are notorious for their evil pollen attacks on humanity, the wood they produce is really quite different.


Planks of sugi

Sugi wood is the cheaper of the two and by far more common. It is reddish-pink in color, coarse grained, and has a wonderful, sweet, oily fragrance similar to cedar (which may be why it's called the "Japanese cedar" even though it's more closely related to the California redwood). It is lightweight, resilient, and highly resistant to decay. However, it is actually kind of brittle. Though it holds up well against constant pressure, it is relatively easy to split with a sharp blow and easy to cut with a saw. That makes sugi a very workable wood but also limits its reliability in some applications.


A hinoki board

Hinoki wood is less common, of course, and it is highly prized. High-quality types can be very expensive. It is a very beautiful, yellow-white or pale pink wood with a smooth or marbled grain, and it has a tangy, lemon-like scent when fresh cut. Like sugi, it resists both decay and insect pests, but it is also a heavier and far stronger wood. It can be quite hard to split with impact alone and can withstand a considerable amount of bending. Depending on the quality and the grain, it can also be hard to cut with a saw. Needless to say, hinoki is an excellent wood for building, but its expense and sometimes limited availability mean it isn't universally used.

When my home renewal project started, I noticed that the overwhelming majority of the boards that we tore out, including the main beams, were sugi (albeit of good quality). The rebuild, however, has mainly made use of hinoki for the main beams and planks (mainly because my wife and I are more willing to pay for it!). Some of those new support pillars are as beautiful as they are heavy...and hopefully will last a long time. Meanwhile, sugi's role has mainly been restricted to the smaller planks and slats in the walls and ceiling. Those do tend to get cut a lot, meaning the area around the saws tends to smell pretty good!

My only regret was that the house used to have beautiful hinoki plank flooring. We had a small child when we first moved in, so I decided to reduce the draftiness and hardness by covering all of it with vinyl on the ground floor. I'd hoped simply to take the vinyl off later, but when the renewal project started we found the flooring tape had made mincemeat of the hinoki's surface. My uncle-in-law declared it useless and replaced it with veneer flooring (which he claims is stronger and safer anyway). The original hinoki floor can still be seen in the upstairs hallway, however, so I guess it's not a total loss.

Incidentally, cleanup has also revealed another important difference between the two woods. Sugi ignites readily and burns both very quickly and very hotly, making it an excellent firestarter. As for hinoki, its shavings and chips burn well, but boards of any size don't ignite so easily and tend to burn only very slowly. A lot of older and/or cheaper Japanese houses use sugi as their primary (if not sole) building material, which probably explains why they tend to wind up piles of ash quickly if any fire breaks out. Newer homes, on the other hand, tend to have hinoki frames, making them a bit more fire resistant. Even so, the best way to avoid having one's house burned down is not to do anything that might cause it to catch fire in the first place!

The main construction is DONE!!! All we have left is the little tidbits of interior decorating...and figuring out where to put everything. Then I promise I'll post some pictures!