Monday, February 8, 2016

How Wood is Made

The early years of the Wood Collectors Society newsletter were full of excellent material. There were a lot of wood scientists, experts, and collectors who for the first time had a outlet for their literary skills.

The following article is one of those gems. Written by IWCS member #14, Dr. Emanuel Fritz, this article is an excellent example of how complex science used to be so well simplified that even the most casual student could understand the subject. Dr. Fritz was a legend in California, and when he passed away in 1988 at the age of 102, the Los Angeles Times ran this obituary.
Emanuel Fritz, 102, a forestry and conservation authority who was known as "Mr. Redwood." Fritz helped create California's forest program and was co-founder of the Regional Parks Assn., the forerunner of the East Bay Regional Park system near San Francisco. He was a professor of forestry emeritus at UC Berkeley, having joined the faculty in 1919 and retired in 1954. Fritz lived the longest of any professor at Berkeley, the university said. Fritz's contribution to the field of forestry was honored this year by the Redwood Region Logging Conference 50 years after he founded it. He advised elected and appointed officials on the need to balance demands for lumber in a rapidly growing state with the need to preserve old-growth groves, replant logged areas and set aside areas for protection. On Thursday in Berkeley.
Here is his article from the November, 1949, edition of the newsletter of the Wood Collectors Society.

How Wood is Made
Dr. Emanuel Fritz, Member #14 

Wood is a complex aggregation of millions of cells. Essentially the individual cell of wood is not much different from the cell of any plant. Each has walls and a cell cavity. Each, when formed, contains protoplasm and other substances, essential in the life process. Wood cells are often large enough to be visible without the aid of the microscope -- for example, sugar pine and redwood among the conifers, and oak and chestnut among the hardwoods. More often, the cells are so small as to require a hand lens to make them distinguishable. Even in a wood like oak or redwood, some cells are large, others quite small.

Cells are generally box-like, closed all around except for the "pits", window-like openings, on side and end walls. Where a window has glass to close the "opening", the cell has a very thin membranous tissue, much thinner than the cell wall around it.

When the cell is first formed, its wall is extremely thin and the cell itself has still to grow in size. As the cell grows to its final size, its walls thicken. This thickening occurs inward; that is, more tissue is piled up or added to the inner surface. Cells in the summerwood portion of a wood like Douglas-fir or longleaf pine have much thicker walls than the cells in the springwood of the same growth ring. Such extra thickening causes the cell cavity, or "lumen", to be very much smaller in the cells of the summerwood.

All wood cells come from the "cambium". As they are generated - by cell division - they become specialized, or differentiated, and several types of cells are thus developed. Some will function primarily for strength; others for conduction; still others for food storage. (These will be discussed in a later paper.)

The cambium is a remarkable organization. Nature causes it to do things that make it appear almost human in intelligence. When nature steps on the gas in the spring, the cambium jumps into action and keeps in action until the season's tank is dry. Then the cambium rests, like a car in a garage. The cambium is really a single row of cells between the wood and the bark. This row of cells belongs as much to the bark as it does to the wood. It is common to both. But it is the only layer on the trunk of a tree that has the power to multiply and yet remain the same. Each cambium cell splits in half. These two small halves each begin to grow larger. One of them will grow into another cambium cell like its predecessor. Another will grow into a wood cell, a ray cell, a vessel segment or another type of cell. This is where "intelligence" comes in. How does the tree, (or the cambium cell), know when it is time to make wood or bark, or any one of the several types of cell making up wood and bark? Don't write me about it. I don't know.

When the cambium is engaged in the above business, naturally, there are some freshly created cells that are not yet fully grown either as to size or wall thickness. But there is only that uni-cellular row which we call cambium and which can continue the business of making new cells. Collectively, all the young cells hatched from the cambium, from the most recently created to the one still finishing up its growth, make up what we call the cambium (or cambial) zone. This zone of course will be several cells thick. It is quite weak, and for that reason the bark is easily peeled from a tree in the spring time. Don't confuse the cambium (or cambial) zone with the cambium. Only the latter possesses generative tissue, i.e., the ability to give birth to new cells. The cambial zone includes the cambium itself and the new and incomplete cells recently born from it.

The new cells stay put, once they have reached their full size. But the new cambium layer itself moves farther and farther away from the center of the tree. It's a sort of centrifugal displacement.

Obviously, the new wood cells pile up against the outside of last year's growth ring. But the new bark cells are formed against the inner face of the older bark. The bark moves outward. It can't stretch as the circumference of the trunk increases, so the older parts crack and the result is the grooves or fissures one associates with the bark of pines, cedars, oaks, hickories, etc. (The bark of the beech, birch, eucalyptus, and madrone are somewhat different, but they too move outward as the wood cylinder increases in diameter.)

The above is in non-technical terms. We crawl before we walk. If the editor is satisfied with this modest note, maybe we can later add some technical terms from time to time. But first of all we ought to look at a cross section of a tree trunk and discuss it. That would make this note too long, so we'll take it up next time. 


Tuesday, January 26, 2016

Hobby Pays Off For W.F. Pond, Member #13

Many people who come to love the hobby of wood collecting have professional backgrounds in which a knowledge of wood science is tangential to their work. Here's an example of how one such early member of IWCS used his knowledge of wood chemistry to drive the development of a new product for his company. By William F. Pond, from Volume 2, Number 11 (1949) of the Bulletin of the Wood Collectors Society.

Several people have asked me at times; "Bill, what pleasure can you get out of collecting a few old sticks of wood?" They do not know of the intense pleasure of collecting a "few old sticks of wood." If they did, I might wake up some morning and find my holly, mimosa, and dogwood trees had been cut during the night. Neither do these people know how my knowledge of trees and wood, meager as it is, was recently of the utmost value to me in my daily work.

Last year, it was found, quite by accident, that a certain inorganic chemical we manufacture when used in conjunction with certain of the natural tannins and saponins, greatly reduced the deposition of scale in boilers in condenser tubes. Scale is the enemy of efficient boiler operation. The typical boiler scale consists largely of calcium sulfate, calcium carbonate, magnesium sulfate, magnesium carbonate, along with some silica, and the oxides of iron and manganese. Deposited as a hard, tenacious scale, this pest results in lowered heat transfer, more fuel consumption, not to mention corrosion.

The discovery seemed so fraught with possibilities, it was assigned to my department as a research project. Several hundred gallons of various hard waters were obtained for this study. These waters were notoriously bad actors. Several of the various tannins and saponins were obtained and the study started.

A period of eight months was spent on this study, during which period some three hundred laboratory experiments were carried out. Many gallons of water containing various combinations of chemicals were greatly reduced in volume by boiling and the nature of the scale examined. At the end of the eight months period, the outlook was very favorable, so operations were started on a pilot plant scale, which confirmed the favorable results obtained in the laboratory. Naturally, our thoughts next turned toward a patent, and here especially, is where my smattering of botany came to the rescue. Before we cover this, however, let's take a look and see how botany, (especially dendrology) entered the picture from the first.

The tannins are astringent, aromatic compounds, acid in character. These tannins precipitate the alkaloids, mercuric chloride, and the heavy metals. Added to solutions of ferric compounds, they form black or blue inks. Dissolved in strong alkalies, as caustic potash, they are excellent oxygen absorbers. The best known and commonest tannin is tannic acid, which chemically, is penta-digalloyl glucose, C14H10O9. Gallotannic acid, C76H52O46 is a closely related body. The list of tannins is quite lengthy; a few more may now be mentioned:

di-beta-resorcylic acid
hamamelitannin
ipecacuanhic acid
fraxitannic acid
m-digallic acid
Maclurin
Quercin

Chemically, these tannins are therefore compounds, containing several benzol rings hooked up with a monosaccharide. The chemistry of the tannins is far from complete and frequently new data becomes available.

The saponins are glucosides of the type formula C32H54O18. Glucosides, incidentally, are chemical compounds which on hydrolysis yield an acid and a monosaccharide, mostly of the type glucose or maltose. The plant world is full of glucosides. Amygdalin is found in the bark of Prunus serotina. Salicin is found in certain species of Salix and Populus. The saponins are white powders, soluble in water, the solution foaming like soap when stirred or shaken. They are toxic and have antiseptic properties. Sasanqua saponin, C73H118O22 ' 3H20 from Camelia sasanqua is a typical one.

With the information our research had yielded, we found it would be necessary to know the botanical sources of these tannins and saponins. Knowing that I dabbled in botany and particularly dendrology, this assignment was given to me. Searching through the chemical texts and my own library on dendrology, it was not a difficult task to make a list of those species yielding commercial tannins and saponins. The following lists showing some of these commercial sources (by no means a complete list) are now offered:


TANNINS

1. Rhus copallina        (Anacardiaceae)        l. 17-38
2. Pistacia spp.             "                  g. 30-40
3. Schinopsis spp.           "                  e. 35-65
4. Aspidosperma spp.      (Apocynaceae)         l. 27-30
5. Alnus firma (minibari)  (Betulaceae)         f. 25-28
6. Terminalia chebula      (Combretaceae)       n. 30-40
7. Terminalia oliveri           "               b. 30-35
8. Larix europoea           (Pinaceae)          b. 9-10
9. Larix occidentalis           "               b. 10-12
10. Tsuga canadensis            "               b. 7-16
11. Castanea dentata         (Fagaceae)         b. 6-8
12. Quercus agrifolia           "               b. 19
13. Quercus aegilops            "      e.30-65; a. 17-40
14. Quercus cirris              "               g. 35
15. Quercus infectoria          "               g. 24-60
16. Quercus rubra               "               b. 25-30
17. Quercus tinctoria           "               b. 25-30
18. Quercus prinus              "               --------
19. Lithocarpus densifolia      "               --------
20. Acacia angica           (Leguminosae)       b. 20-25
21. Acacia binervata            "               b. 30
22. Acacia catechu              "               e. 60
23. Acacia decurrens            "               b. 20-61
24. Acacia microbotrya          "               b. 12-47
25. Acacia pycnantha            "               b. 40-50
26. Caesalpinia coriaria (Jacq.) Schl. -- Libidia coriaria:
      (Divi-divi; libi-libi) (Leguminosae)      p. 30-50
27. Pterocarpus spp. (Kino)     "               e. 40-60
28. Xylocarpus granatum      (Meliaceae)        b. 21-48
29. Eucalyptus spp.          (Myrtaceae)        --------
30. Rumex hymenosepalis      (Polygonaceae)     r. 25-30
31. Braguiera spp.          (Rhizophoraceae)    b. 22-52
32. Rhizophora spp.                "            b. 21-58
33. Nauclea gambir             (Rubiaceae)      --------

The small letters to the right mean: a - acorns; b - bark; e - extract; f - fruit; g - galls; l - leaves; n - nuts; p -pods; r - roots.

The numbers in the extreme right column refer to the percentage of tannins obtainable.

SAPONINS

A partial list of the commercial saponins is now offered showing the botanical sources;

1. Saponaria officinalis             (Caryophyllaceae)
2. Quillaja saponaria                (Rosaceae)
3. Mimusops globosa                  (Sapotaceae)
4. Bumelia retusa                    (Sapotaceae)
5. Sapindus spp.                     (Sapindaceae)

The above list is by no means complete, but it will serve to show the source of a few of the saponins. The Sapotaceae is the source of many of the commercial saponins. Incidentally, the drupe of Melia azedarach contains a saponin like body.

With our research now completed and our botanical nomenclature in order, we were able to make the patent application in which it was necessary to name the botanical sources of the commercial tannins and saponins. It was rather interesting to note the reactions of the various other chemists in the organization. Soon they were reeling off the terms Quercus, Terminalia, Schinopsis, etc., like old hands.

So, when my friends wonder why I find pleasure in collecting a few old sticks of wood, I can say I find it profitable in two ways, viz., the intense pleasure it affords me which cannot be measured in terms of the dollar, and finally, it came to my rescue when confronted with a difficult chemical research problem.

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