Timbers converted

Primitive people very likely encountered vinegar-like Hquids in hoUows in rocks or downed timber into which berries or fmit had fallen. Wild yeasts and bacteria would convert the natural sugars to alcohol and acetic acid. Later, when eady peoples had learned to make wines and beers, they certainly would have found that these Hquids, unprotected from air, would turn to vinegar. One can postulate that such eady vinegars were frequendy sweet, because the fmit sugars would have been acted on simultaneously by both bacteria and yeast. Only since the middle 1800s has it been known that yeast and bacteria are the cause of fermentation and vinegar formation. 

For some uses, the anisotropy of timber and its variability due to knots and other defects are particularly undesirable. Greater uniformity is possible by converting the timber into board such as laminated plywood, chipboard and fibre-building board. 

The major part is used as firewood or timber only 13% is further processed by mechanical and chemical treatment. The common process to convert wood into wood pulp is the Kraft process, which uses a mixture of sodium hydroxide and sodium sulfide to separate lignin and cellulose. The resulting cellulose is predominantly used for the production of paper and board. Only a small percentage (4%, 4—5 million tonnes) is further processed chemically. 

Among the hexachlorooctahydronaphthalene type compounds, aldrin [309-00-2] was one of the earliest pesticides. It was first synthesized in the United States in 1948. It was produced by Diels-Alder reaction from acetylene and hexachlorocyclopenta-diene. Aldrin readily converts into dieldrin [60- 57-1] on exposure to sunlight or bac-terias. Both aldrin and dieldrin were widely used from 1950 to 1970 for protecting com and cotton crops. They were also used to protect citrus plants and combat soil pests and locust and in the preservation of timber. Because of their high toxicity and hazard to human health, the production of these pesticides ceased in the United States in 1974. After 1974, the uses of these pesticides were limited to control termites. All uses of these... 

Between the cutting of timber and subsequent acid conditions, more than 130 km (50 sq. miles) were completely defoliated (6). Around the turn of the century processes were developed that allowed the SO2 to be captured and converted to sulfuric acid. This not only put an end to first example of acid rain in this country, it also proved to be a profitable endeavor that continued even after the mines were closed and sulfur had to be shipped in to Ducktown for the manufacture of sulfuric acid This is just one case that demonstrates well the advantages of benign synthesis. If it had been possible to obtain both copper and sulfuric acid initially, the damage could have been averted. 

Forests have been used unsustainably for millennia. Forests have been converted to pasture for livestock, used to smelt ores, or to manufacture timber, tar, and other products. Trees have been turned into charcoal and removed from mountain tops to mine the ores below. Forestry originated in attempts to prevent the overuse of forests. For example, in the eleventh century, William the Conqueror established forest laws governing the usage of vegetation and wild game. 

European Standard EN 152-1, 1988. Laboratory method for determining the protective effectiveness of a preservative treatment of converted timber against blue stain in service (brushing procedure). 

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