Thursday, November 21, 2013

Can't See the Forest for the Trees

There is a Japanese proverb used in temple carpentry, "木を買わず山を買え", ki wo kawazu yama wo kae, which translates as "don't buy the tree, buy the mountain". This proverb is known to have been uttered by Nishioka, Tsunekazu, who was tasked with the rebuilding of Yakushi Temple in Nara.

The meaning of the proverb relates to the building of a large complex of structures, like a temple compound, a situation in which you will have buildings, and portions of buildings, which are in a variety of unique environmental situations. Those conditions might be south facing, or north facing, or down in a valley, or up on a hill, there might be places where the columns are crowded together or spaced widely apart, etc. The idea behind the proverb "don't buy the tree, buy the mountain" is trees that are to be used in such buildings, and compounds of buildings should ideally come from a place which replicates the idiosyncrasies of conditions as closely as possible. So it's not a matter of choosing trees for cutting into building components on a one-by-one basis, each tree considered more or less the same as the next, but rather to make one's assessment each tree on the basis of where that tree grew in relation to its environment and to other trees around it. As environment has an effect upon which genetic traits are expressed more strongly in the tree, and which growth form is seen in a given tree. A tree growing in a damp place, or a windy place, in a grove with other trees or alone with no competition for sunlight, or on a slope, will all vary in how they form. There's no reason to believe that trees aren't every bit as varied in terms of how they turn out based on the mix of inherent and environmental factors they experience than are people.

Since the environment in which a building is situated also places similar varied conditions upon the timbers in the building - a sunny side, a windy side, a damp place, etc., it makes sense to take a broad view than a narrow one when choosing the trees which will form the basis for wooden structures.  In optimum circumstances then, the role of the master carpenter is to take the variances of the environment in which the trees were grown into consideration, and select the use and position of the material cut from those trees in the building, or even in the compound of buildings, most carefully.

As one tree has its north-, east-, south- and west-facing sides, one could divide the trunk of that tree into four posts which are placed in the building as the northwest, northeast, south east and southwest posts. Moving up from the consideration of a single tree to the mountainside covered with trees, and imagining we might take an entire tree and convert it into a single large post, say, we can similarly place the trees from the north side of the hill to the north side of the building, and so forth. The challenge with such an approach however is that of labeling. Not only do the trees need to be tagged so their position in the originating environment is clearly indicated, but the north, east, south and west faces of the trunk must also be indicated. After cutting, these delineations must be maintained in the sawn timber. For any of that to have a hope of working, the master carpenter would do well to be present from the outset and oversee the processes of conversion, and that is a rarity today, even in Japan.

Most workers in wood are buying their lumber from a dealer in sawn lumber, and never see the log from which the timber was obtained, let alone the place in which the log grew. And neither did the dealer for that matter. And sometimes not knowing those things can lead to poor outcomes. We've all bought wood which had a lot of reaction in it, rendering tremendous waste and frustration instead of smooth progress in our work.

Trees are structures adapted to resist loads from gravity, which increases as they get larger - I refer to compression loads. The lowest portion of the tree trunk is subject to the greatest compression loads as the mass of the tree lay above. A tree is stressed by the wind, on a regular basis, which induces bending and or torsional loads. Other bending loads can be induced if the tree grows at a lean, or has become curved at the bottom of the trunk in response to ground creep on a hillside. The middle of the trunk, considered lengthwise, takes the most of these bending loads, as it is able to flex more than the butt of the tree. The thinner the trunk, the more it will bend and yield to wind, gravity and snow loads. 

Given these differences in how the loads are apportioned in a tree, it makes sense to consider which timbers in a structure come from which portion of the tree trunk. Posts should, logically, come from the lower end of the tree, a little bit up from where the most pronounced flare at the very butt end is located. The section of trunk above that bottom 10~14' would be a good place from which to obtain beams, as beams are subject to bending and torsional loads to a greater extent than compression in most cases. The role of the master carpenter is to assess a given tree trunk in light of such considerations, considering the timbers required and make decisions about where the trunk is to be crosscut and which timbers come from which section. Some projects will require posts and beams, some will also require wide planks, and how one might choose to cut trees for a project would be factoring in such things.

All of this makes good sense, however all of this is almost an impossibility in this culture, as we simply do not consider trees in their individuality, rather we see it more often as a material to be purchased by the cubic meter, or linear foot, and only have the coarsest divisions to consider, like flatsawn vs quartersawn, etc.. It's a very rare opportunity for a woodworker to even pick the logs from which the timbers are sawn, let alone pick the logs in the forest, or select from what portions of the mountain the timbers are cut. The people who make the decisions about where and which trees are cut are making those decisions not on the basis of fiber quality and best use, but in terms of things like property rights, landscape design (so as not to horrify too many people driving by the cut block), forestry regulations, the amount of cubic meters permitted to to be cut, the health of the trees to a certain extent, straightness of the logs, and which lengths are convenient to fit on the logging truck. The people who saw the logs into timber are generally considering volumetric conversion efficiency as it is most profitable to do so, or, less commonly and especially in certain woods more than others, based on obtaining quartersawn or rift sawn material for particular needs. Obviously, if you're processing 50,000 board feet of material or more a day, say, then slight changes in cutting process for a few percentage points improvement in conversion rate can make a significant difference to the bottom line. And since the bottom line is really all that matters in such concerns, it is inevitable that they move in that direction. 

On a personal note, I've had arguments and hassles with sawyers in the past because I've asked them to saw for quality when their habit, as it soon becomes apparent, is to saw for volume and profit. The easiest thing to do is to lay the log down on the deck and run through and through as many cuts as possible, with as few flips, set-ups and rotations of the log as possible. Get it done fast and move onto the next one is the mantra, even when it is a one-man sawing business with a Woodmizer. You may as well be cutting styrofoam for all the consideration generally given to the nuances of the tree's fibers. How the tree is constructed by nature seems almost besides the point, and this is too bad really.

Also, it might be worth noting that since the vast majority of lumber is either going to be used in largely unmodified form (as with framing lumber), or is going to be processed almost entirely by machine and power abrasion when it is further converted after sawing and drying, the issue of grain orientation becomes less of a factor than it is when the wood is to be worked by hand tools. Only a very small percentage of people are going to work wood that way, so it hardly makes sense to consider their needs in terms of how timber might be cut. And of course, it is worth considering the fact that wood was worked by riving, using straight-grained timber  - this was the norm for millenia, and the saw was a relatively late comer on the scene, coming well after other carpentry tools had been developed. The saw allowed a move away from following the grain of the wood, allowed wood without straight grain to be conveniently worked, and in many ways this seeming technological advance was in fact a negative in terms of the craftsmanship side of the picture, in terms of working wood truly according to its nature. Such was pointed out by H. Phleps in his work The Craft of Log Building: A Handbook of Craftsmanship in Wood, and I agree. But there is no going back in that regard, and our forestry practices do not tend toward the production of large, knot-free straight grained slowly-grown timber.

I'm just pointing out that the people choosing the trees to be cut, the people cutting those trees and converting those trees into lumber are all people who are NOT working the material and building the structures. How could they possibly know what might be most ideal from those end-use perspectives? So they perform their work with other imperatives in mind. And on the end at which the timber is being fabricated, the framer or furniture maker typically knows very little about the place from which the timbers originated, and had no option to consider anything other than a cost/board foot equation and maybe select grain to an extent. We work bubinga or redwood, or hornbeam or pond cypress and we may never have even seen one of those trees growing, producing cones, nuts, flowers, or such. It's just so disconnected.

So, carpenters tend to end up largely oblivious to the organisms from which they obtain their material, and such is the same, I would observe, for many other artisans. How many blacksmiths have mined ore and smelted their own iron? How many potters have dug their own clay out of the ground? I'm sure a few, but not most. Some crafts, like basket-making, do feature, at least more commonly, a much more direct link between the artisan and their material, but it seems more the exception than the rule. That link, if it was there, would be of some benefit to the maker I'm sure. I'm not suggesting it makes sense for a woodworker to also be a logger, skidder operator, trucker, sawyer, and dryer of timber, but at least to try to have an increased familiarity with those aspects  - this seems a worthwhile avenue of investigation, does it not?

The point here is that, the way the system has been set up, the woodworker ends up in many cases with little real connection to the trees they use, and the planting of pine boughs atop the timber frame (which may not be made from pine in any case) remains, I suppose, a quaint custom at best, and strikes a slightly bittersweet chord for me. This situation is unfortunate, and it is a result of the inexorable process of division of labor (specialization) in our society. There is little in the way of a constructive feedback loop happening here, except on the industrial scale, where big woodcutting outfits, like Weyerhouser and Fletcher challenge, own the cutting rights to vast swaths of land and also run large mills of various kinds, and thus their concerns alone drive much of the decision making in regards to how the forest is treated. And the evidence would seem to show it hasn't been treated all that well, has it?

That's another issue of course, and I guess for this post I'm choosing not to head down that path any further. The path I do want to head down is to look at logs and their conversion into timber. In the next post or three in this series we'll do that.  It seems like a topic worthy of some exploration, and I hope you'll stay tuned.

6 comments:

  1. Guilty as charged. I'm a woodworker disconnected from much of the lumber I have but have chosen to change my lumber buying habits. I'm buying from two dealers, Dan who goes back to the MidWest a few times a year and brings back lumber he and his brother haves from their land on the Missouri Breaks and a local sawyer one man Woodmizer who harvest trees of his on land up on Moscow Mountain which I drive by most days. Used to be able to see Moscow Mountain from the house but our trees grew to tall and dense.

    Thanks for the wake up. Being more connected is a goal. To that end I've been carving wooden spoons and that requires a very fresh piece of timber thereby connecting me with its harvest, usually. Thanks again for the post and I look forward to the "next".

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    1. Will,

      thanks for sharing your thoughts. It's hard to be as connected to many facets of our modern life, given the way things are set up. I think one of the common points between woodworkers is an appreciation for trees and a liking for working with a natural material, and the more we can know about that material, perhaps, the more we can appreciate it.

      ~C

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  2. Looking forward to this series of posts!

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    1. Jamie,

      thanks - good to hear from you - and I'll do my best in regards to the next posts in the series.

      ~C

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  3. I enjoyed reading this. As a framing carpenter most guys might know wood shrinks across the grain and that's about it. The vast knowledge of timber you described was refined over generations and is probably a thing of the past... Problem is, most guys reading this are probably old farts like me. We are fascinated with wood and woodworking, if we are lucky we will leave behind a couple of pieces for furniture for our kids, and our tools will end up on Ebay.

    Sad thing is, a lot of kids now may be able to read your post and spout off all kinds of bits of knowledge, but... I have worked with young guys who don't have the common sense to nail a couple 2x4's together without splitting the ends out, yet they want to second guess and debate every single detail that comes up in a day.

    Thanks for the read.

    Steve



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    1. Steve,

      your well-considered comment was good to receive. I'm not really sure if the reader base here is tilted towards young or old, however I do have the impression that fewer and fewer young people have much exposure to working with their hands in any context, and very rarely at school, and thus it is often the case that they develop little appreciation for the vast pool of knowledge that has built up in the various mechanical arts over time. It's unfortunate but whatcha gonna do?

      I feel lucky to have grown up in a family where it was normal to take things apart and fix them, to take on construction projects of all sorts. I think to have formed, at an early age, the idea that things like that can be tackled and that tinkering is a good thing, was a key piece of the puzzle for me, and I suspect something similar for many others who work with their hands.

      ~C

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