Wood harvesting

Annua.1 Production. The United States is the largest single producer of lumber with about 25% of all the logs cut in the world. The current soft housing and constmction markets as well as environmental pressures to limit logging are reducing the percentage. Still the value of wood harvested was about 12.6 biUion in 1989. 

Table IV. Biomass and nutrient losses associated with wood harvest (fuel wood or timber export) and fire in selected forest ecosystems.

The additional wood demand of 17.1 Mio m3 corresponds to 27% of the total German wood harvest in 2006 (62.3 Mio m3). The wood harvest of 2007 of 76.7 Mio m3 cannot be used as typical reference due to the windfall of the storm Kyrill . The harvested wood volume in 2006 has already doubled in comparison to the long-term average of the 1990s (approximately 34 Mio m3) [9],... 

While the harvesting of trees for energy alone is likely to be too expensive, the unutilised forest of Canada could theoretically double the present wood harvest, though this would have to come from the area of the forest classified as tertiary below. 

The major releases of terrestrial carbon result from the oxidation of vegetation and soils associated with the expansion of cultivated land. The harvest of forests for fuelwood and timber is less important because the release of carbon to the atmosphere from the oxidation of wood products is likely to be balanced by the storage of carbon in regrowing forests. The balance will occur only as long as the forests harvested are allowed to regrow, however. If wood harvest leads to permanent deforestation, the process will release carbon to the atmosphere. 

Probably the most common worldwide use of oak is as fuel. Oak burns very hot, providing up to 23 million BTU per cord. Charcoal made of oak was extremely important to small local industries during the nineteenth century. Most hardwood forests are managed for fuel wood harvesting or lumber, with oaks considered the most valuable species. 

North Carolina Wood harvesting and pulp mill residues (black liquor)... 

Almost 70% of the land biomass is produced in forests (ca. 27 Gt C/y). The major part of the production are falling and rotting leaves etc. the valuable wood and woody parts make up only about a quarter or less. With a world forestry management including afforestation, a sustainable wood harvest of about half of the up-growth can be expected. This corresponds to an about three-fold increase compared to the present production of timber plus commercial firewood (ca. 2 Gt/y). 

Model Number 1 — Traditional Round Wood- This model exemplifies many small wood harvesting operations and consists of two men and one skidder. One man is responsible for felling and cutting the tree to... 

The total world wood resources is estimated to be about lO" tons. About 10 tons is felled per year. The largest proportion of wood is used as fuel or in the construction industry. About one sixth of the wood harvested is used as a source of cellulose for paper and pulp. Lignin has only slight significance as a raw material, hemicellulose has none. 

Wood consists essentially of cellulose (Section 31.5), lignin (Section 32.3), hemicelluloses (Section 31.5.1), and water. The major uses of wood are for fuel and as a construction material. Also, of all the wood harvested, about one-sixth (150 million tons per year) serves as a source of cellulose for paper and pulp. For this purpose, it first has to be freed from lignin and hemicelluloses by certain digestion or disintegration methods (Section 32.3). 

In contrast with the crops mentioned, essentially all of the wood harvested is destined for industrial uses, rather than food/feed uses. Production of wood for lumber in the United States amounts to about 170 million tons per year while U.S. pulpwood production (destined for all kinds of paper uses) is about 90 million tons/year. A wide variety of industrial chemicals such as turpentine, gums, fats, oils, and fatty acids are produced as byproducts of pulp manufacture. 

For functional products [7], wood is an important material for construction. Two-thirds of the wood harvested is used for this purpose. The remainder is used for paper pulp and as chemical raw material. 

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