Tag Archives: Trees

Trees are Air and Water

Trees are made from air and water. How much of the wood comes from air and how much comes from water? Let’s do the calculations.

Dry wood is mostly cellulose, chains of C6.H10.O5, molecular weight 6*12+10*1+5*16 = 162.

The production of cellulose, in overview, is 12*C.O2 (from air) + 10*H2.O (water) –> 2*C6.H10.O5 + 12*O2 (back to air). Each C.O2 has weight 44, each H2.O has weight 18, and each O2 has weight 32. Thus the formula, in terms of molecular weights, is 12*44 (carbon dioxide from air) + 10*18 (water) –> 2*162 (cellulose) + 12*32 (oxygen back to air).

Multiplied out, 528 grams of carbon dioxide from the air, plus 180 grams of water, makes 324 grams of cellulose and releases 384 grams of oxygen back to the air. The process uses 75 percent air and 25 percent water, by weight.

Incidentally, notice that the number of C.O2 gas molecules consumed in the formation of cellulose, equals the number of O2 gas molecules released. There is no change in air pressure as a result of tree growth. If there were an excess or deficit of gas molecules resulting from plant growth, we might expect some interesting breezes and weather effects near forests and fields. Every aspect this world fits together! I have a naturalist friend who says he can tell there is lots of oxygen in the area behind my house — which is surrounded by lush woods and growing plants. Maybe so. I used to be able to detect low oxygen in the stacks of a poorly ventilated library, where the many book pages were slowly oxidizing.

The above is not, however, the full story about the constituents of wood. Living trees are not dry wood. They contain about 50 percent by weight of water. So let’s revisit the calculation. Consider an amount of living tree, let’s say 200 grams. Half of it (100 grams) is 75 percent from air and 25 percent from water. The other half (100 grams) is 100 percent water. The total amount of living tree comes 37 percent from air and 63 percent from water.

There’s even more. Dry wood is not free of water. It contains about 12 percent water. So again consider an amount of dry wood, let’s say 200 grams. The majority of it, say 88 percent or 176 grams, comes 75 percent from air and 25 percent from water. The remaining 12 percent, 24 grams, is moisture trapped within the “dry” wood. Total water content of the 200 grams, as water or as cellulose partly derived from water, is 34 percent. The dry wood is two-thirds (66 percent) derived from air, and one-third water or derived from water.

Conclusion: Dry wood is mostly derived from air. Green wood is mostly either water or derived from water.

Here’s a nice tree experiment from about 350 years ago. It exemplifies scientific patience and careful observation. It also indicates how, despite careful and accurate observation, one can make a mistake by using the wrong model.

This experiment was performed by Jan (Johannes) Baptista van Helmont, and reported in 1648. Van Helmont wished to determine which of the four elements (earth, water, air, fire) was the predominant contributor to plants. More exactly, he believed that plants were mostly made from water, and wished to validate his hypothesis. Here is his report of his experiment, which took five years:

Van Helmont: “That all plants immediately and substantially stem from the element water alone I have learnt from the following experiment. I took an earthern vessel in which I placed two hundred pounds of earth dried in an oven, and watered with rain water. I planted in it the stem of a willow tree weighing five pounds. Five years later it had developed a tree weighing one hundred and sixty-nine pounds and and three ounces. Nothing but rain (or distilled water) had been added. The large vesel was placed in earth and covered by an iron lid with a tin-surface that was pierced with many holes. I have not weighed the leaves that came off in the four autumn seasons. Finally I dried the earth in the vessel again and found the same two hundred pounds of it diminished by about two ounces. Hence one hundred and sixty-four pounds of wood, bark and roots had come up from water alone.”

That quote is from William H. Brock’s book “The Chemical Tree: A History of Chemistry”, which has also been published under the alternative titles “The Fontana History of Chemistry” or “The Norton History of Chemistry”. It begins the introduction of Brock’s book and justifies his title “The Chemical Tree”. A well-written book, enjoyable reading.

Van Helmont’s mistake, is that his model did not include the invisible air, which it turns out contributes about three-quarters of the mass of the tree material. He also excludes sunlight (= energy = fire) from his contributing elements. And of course the earth is also necessary, for nutrients and trace materials, and for support and context for the tree’s life (growth medium). One might say, in the four-element categorization, that trees depend upon all four of the basic elements, and could not flourish were availability of any one of those elements blocked.

We make advances by relying upon our predecessors. Van Helmont was a creative and careful experimenter. But all experiments benefit from prior experiments and also from sincere critiques from others.

An article in Plant Science Bulletin by David Hershey has a very interesting discussion of Van Helmont’s experiment. There are predecessors, contemporaries and later scientists who made related experiements. Hershey draws some conclusions about the scientific process, and also about the teaching process. The best formatting of the article is at this URL:
http://helmont1.tripod.com/hersheypsb49-3.htm
but it is also available at Plant Science Bulletin, vol 49 no 3 (2003), at this URL:
http://botany.org/PlantScienceBulletin/psb-2003-49-3.php
The Hershey article also quotes the above paragraph of Van Helmont’s in a 1662 translation, rather archaic language but useful as there are subtle differences between the 1662 translation and the more recent translation. If I could read Latin, perhaps there would be other subtleties to discover. However, there are other avenues of investation to pursue, and Latin does not make my priority list. German though … very important for science, of the past century and contemporary work.

Let’s have a photo of Jan Baptista van Helmont:

There’s a story behind this portrait. It has been mis-identified as Robert Hooke (of whom no portrait exists). However, one can see by comparing with other images of Van Helmont, for example in one of his books, that this portrait is Van Helmont.

Articles from Wikipedia about wood drying (re moisture content), about cellulose, about Van Helmont:
https://en.wikipedia.org/wiki/Wood_drying
https://en.wikipedia.org/wiki/Cellulose
https://en.wikipedia.org/wiki/Jan_Baptist_van_Helmont

Best wishes,
Ken Roberts
22-Jun-2015

Log Slice Table 2

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The top for the new log slice table is mostly finished. Here is a photo. It is about 55 cm diameter.

Those interesting black lines are something that elm wood has. That’s one reason I like to use it. They are not the rings — the rings can be seen, and counted, though they are not prominent visually. This tree was about 40 years old.

To supplement the comments on finishing which I made in the previous post: I put four coats of spar urethane on the top. Spar urethane is intended for marine use — outdoors or indoors — and is very durable. The first coat was applied to the top only, and really soaks into the wood, because it is being applied to end grain. The second, third, and fourth coats are applied pretty thickly, and the sides (edges) of the slice are also urethaned at the same time. Just an extremely light hand sanding is done to each coat, prior to applying the nexct — the sanding is so light it is invisible, and just develops a bit of tooth on the surface. Coats at intervals of about 12 hours. After the fourth coat, the top surface is smooth and sealed.

As it happens, in the upper left corner of this photo, if you look at the enlarged image, you can see the little tool (for rug hooking?) that I use to clean the bark off the log slices.

Now I will wait several days for the urethane drying to complete, then turn the slice over, and seal the bottom surface. Then make the legs.

Best wishes,
Ken Roberts
03-July-2014

Log Slice Table

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Here’s a log slice table that’s pretty easy to make. What you need is a thick slice of some interesting wood — elm is a good choice as it has curious lines within it. And you need a router and a portable belt sander. Let the wood sit for a long time — years perhaps — to ensure it is thoroughly dried out inside. The next time you have a tree cut down, ask the workmen to save you 3-4 slices of the trunk, each slice about 15-20 cm thickness.

The second photo shows the log slice being flattened using the router. The wood box provides a sturdy frame with two flat rails, the slider for the router moves at right angles to that, and you draw the router back and forth to mill the log slice flat. The little wooden strips on top, alongside the router, keep the router from drifting so far to one side that you might gouge out the slider boards.

The router bit is one of the square-bottom profiles; I like to use a 1.2-cm bit, as a 1.8-cm bit chatters too much. Very small depth cuts, maybe 4-6 mm, are made on each traverse. After one level has been taken off, a thin board (foamboard or plywood) can be put under the log, to raise it up for the next round. You are essentially being your own milling machine, without the cost or complexity of a real machine. The tradeoff is your time — it will take several hours to get the log slice just right. I like to flip the slice over a couple of times, to ensure that each face is being milled parallel to the other, with no unwanted bevels at the edges.

Once the log slice is the right thickness with two parallel faces, I like to remove the bark around the edge, so it does not flake off later. I use a small tool with about a 1-mm diameter rounded blunt tip — originally intended for rug hooking, I think. Then sand the faces, and finish them with urethane. Both top and bottom, and the edges, so the log slice does not absorb moisture unevenly.

To attach the legs (which can be anything you find convenient and attractive), I make a plywood flat which can be screwed underneath the log slice, with its profile about 2-3 cm inside the profile of the base of the log slice. Screws are run down through that flat, into the legs. Then the flat is screwed to the base of the log slice. One final coat of urethane, including the legs, and the table is complete.

I’ve made three of these log slice tables in the past, for personal use and gifts, and the one I’m making presently will be the fourth, another gift. It’s been a really enjoyable activity. If you make one of these tables, I hope you have fun.

Perhaps I should mention cautions. Protective goggles and ear muffs, of course. More importantly, there are lots of wood chips flying about — you might want to consider a dust mask. And some woods (eg, black cherry) are poisonous when breathed in as sawdust. Check the woodworking websites if you’re in doubt about the wood which you’re working with. As with any power tool, know where each of your hands is positioned at all times when you are going to use the tool.

Best wishes,
Ken Roberts
29-Jun-2014

Woodpecker Holes

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When a woodpecker drills a hole, looking for a bug, and there is no bug … move a bit aside and try again! Here is a photo of a line of holes in the trunk of a pine tree (trunk diameter about 25 cm).

It reminds me of my experiences, sometimes, when trying to locate a stud behind the drywall to put up some shelf or other heavy object that must be anchored firmly. I tap, listen, feel the springiness of the wall, then drill a tiny hole. No resistance? Move a bit left or right and try again. Behind some of the shelves in my house there is a line of little holes.

Best wishes,
Ken Roberts
05-May-2014

Easter Egg Tree

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It’s the Easter season, so here’s an easter egg tree which makes an enjoyable craft project. The tree is made from copper wire, obtained by stripping ordinary #14 electrical wire. The base is two pieces of oak. The top piece of the base is hollowed out in its middle, to about half-thickness, and holes are drilled in it for the wires to pass thru. The wires are about 1 meter long, so go down, and then come up another hole. Wires are twisted together to make the tree trunk and branches. Attaching the second base piece hihes the wires underneath. A bit of stain and urethane, felt on the bottom, and the tree is ready to decorate. The little eggs are purchased. We also use the same tree at Christmas season, with little ornaments (angel sold as candle-holders) instead of easter eggs. A fun project to make, for oneself or to give to a friend.

Best wishes,
Ken Roberts
18-Apr-2014

Beech Leaves in Winter

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Deciduous trees, most types of them, lose their leaves in the fall. But the Beech tree is different — it loses its leaves in the spring. A beech retains its leaves, dried up and pale yellow in colour, over the winter. The beeches look very nice out among all the other leafless trees in the woods. When spring comes, the new leaf shoots will push the old leaves off the branches.

Today I noticed that a beech was losing its leaves out at the ends of branches, but still had old leaves nearer the trunk. That is an indication that the tree’s spring growth, of new leaves, starts earlier at the ends of branches. The photo below shows the beech which I first noticed.

Also, here is a closeup of a smaller beech nearby that one. You can see the old leaf, and the new leaf shoot just starting.

You can identify a beech twig, by the way, by the angle between a twig and a smaller twig growing off it — the angle is consistently about 70 degrees.

Those beech trees I’m talking about are the species known as American Beech, which is the only type of beech tree which is native to North America. You can read about beech trees in either of two excellent books — R. C. Hosie, “Native Trees of Canada”, 8th edition, 1990, pp 176-177, or the book which later replaced Hosie: J. L. Farrar, “Trees in Canada”, 1995, pp 268-269. Either book is excellent. The Farrar edition has colour photographs which is a convenience.

Waiting for spring…

Best wishes,
Ken Roberts
29-Mar-2014

Observable vs Observation

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If a tree falls in the forest, does it make a sound? Does that depend upon someone being there to hear? That is a classic example of the mixup of two distinct ideas — the idea of an observable, and the idea of an observation.

First of all — consider a specific tree — you know, that shagbark hickory with the funny bend in its trunk, the one near the path. Is that tree standing? Cannot say. It was there yesterday afternoon, but no-one has gone to check since then, and we do not have a TV camera watching the tree. Even if we did have such a camera watching the tree, we could not say if the tree is standing NOW — only that it was standing a second ago, whatever is the lag time between the camera’s recording and the image rebroadcast and viewing by us.

Still, no doubt, whether the tree (that particular hickory) is standing, is an observable — ie capable of being observed at various times. At certain times in the past, the tree may have been observed — via a person or via proxy, eg a TV camera/recorder. Those are observations. One observable, and several observations, at specific times, or possibly no observations. Most of the time no observations, though. We do not watch the tree all the time. We’re not likely to misplace the tree, to confuse it with another tree. But what about the may apple plant at its base? Which one of the hundreds of may apple plants are we talking about? The one with a single leaf? Or the one with a pair of leaves? Or were those two observations actually of the same may apple plant, at different stages of its growth? Observing a living creature, plant or animal, is as unrepeatable as stepping into the same river twice.

All this is preliminary, just to get some distinctions in mind. I have minimal training in philosophy, and there are subtle distinctions that escape me. But I can at least know that we are at risk of serious confusion if we make no distinction between an observable (capable of being observed), and an observation (time-specific event of data gathering).

Is the moon there even if we are not looking at it? Yes, I would say so — the moon is an observable, even if we do not make an observation. Was the moon there a million years ago, when we were not around to observe it? Yes, it was an observable. Sometimes nature will deliver us a delayed observation. That lunar meteorite which I spoke of several weeks ago, was an observation — I observed the meteorite quite recently, but the sample of lunar rock which was propelled into space by an asteroid impact, was a sample taken between last month and perhaps a billion years prior to last month. That meteorite, with some dating work, is late-arriving evidence that the moon was there a long time ago, before there were people around to observe it.

Best wishes,
Ken Roberts
05-March-2014