The Future of Wood Extractives

Two examples are illustrative Shortly after the turn of the century, one of the ten largest companies in the United States was totally dependant upon extractives for its raw material (23). The Central Leather Company, successor to the United States Leather Company, had tanneries scattered all over the state of Pennsylvania, each of which extracted tannin from the bark of the eastern hemlock Tsuga canadensis). Today not only is it the only one of the ten companies no longer in existence, but there is not a single producer of native tannin in North America. 

The gum naval stores industry showed a similar pattern. During 1908, the peak year of production in the United States, more than 120000 tons of spirits of turpentine and 600000 tons of rosin were produced. Due to competition from wood naval stores after World War I and sulfate turpentine and tall oil after World War II, gum naval stores production declined to less than 4000 tons in 1985. The United States government, recognizing the inevitable demise of this product, completed the liquidation of its stocks in 1972, terminated the Naval Stores Conservation Program, and closed the Agricultural Research Service s Olustee (Florida) Research Laboratory in 1973 (44). 

If we were limited to these two examples, it might be concluded that the commercial future of wood-based extractive industries is doubtful. On the other hand, natural rubber production has continued as a major activity in a number of countries in spite of all the attempts to replace it with synthetic substitutes. Carbohydrate gums and mucilages continue to be collected, refined, and utilized in applications unimagined only a few years ago. Almost all of the world s tall oil and sulfate turpentine that can be conveniently captured is sold to fractionators who convert it to a myriad of saleable products and intermediates (Chap. 10.1). 

2 Requirements for Future Wood Extractives Business Ventures 

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Future research. From an industrial standpoint, the major requirements of p-mannanases are thermostability and the ability to hydrolyse crystalline and/or amorphous mannan to low DP oligosaccharides. Enzymes with such properties could find application in such processes as coffee extraction and in enzymic treatment of wood pulp. 

The unextractable acid in wood plays a major role in the catalysis of the urea-formaldehyde polycondensation reaction. The significance of this indication must be viewed in contrast to previous investigations which have attempted to correlate properties of wood with the properties or amounts of extractives. It would not be prudent to generalize regarding the effect of unextracted acids because only seven species were studied. However, in future studies these observations may be found to be generally true for most, if not all, species. 

In terms of volume and value, the most significant wood-based extractives industries are natural rubber, resin and terpenes, carbohydrate gums, and tannins. The reasons for survival, growth, or decline in the future for each of these industries are quite different and are illustrative of the business principles described in the preceding section. 

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