>Is there someone in this very interesting discussion about logging, who has >data regarding the energy consumption >(and related greenhouse gas emissions) of making products from wood as >compared to making them from other materials? > >Best regards > >Bernhard Schlamadinger Dependence on how you make the calculation. Energy budget calculations are difficult to make. If you just want to compare on a weight basis there are statistical information avialable on this matter. To make the energy budget much more must be included. If one considers the total energy content wood and tree should compare quite nicely (J/kg) If the the plastic is considered as produced by energy (fossile fuels) and the wood is "free", plastic is a high energy product. Wood dried in open air is, of course, using less energy than artificially dried. Once more comparing wood and plastic products the latter is usually lighter than the corresponding wood one, e g a garden chair. It is also a matter of lifetime; does a plastic chair last longer than a wood chair? Then, how does aluminum chair compare, which in principle is expected to last for ever? What about recycling? Old wood products can be used as fire wood and the stored energy released or, in principle, old wood can be recycled for paper and / or pulp production allthough I have never heard of that. Plastic can be recycled and your chair might appear once more in your garden as a chair or as glass (made of plastic) in which you have your drink. Even more complicated is a comparision to e g concrete or bricks. By weight and volume these materials are much more energy intensive than wood but they last longer. On the contrary a house made of wood is much lighter than a concrete one. A house made of wood is usually better isolated than a concrete one, compared by weight, some important for us swedes these days, that is the *use* of the products can be included in the calculation as well. Finally, is a long lasting house interesting - there are some economicl considerations also. I am myself convinced that wood is superior in most of these aspects. Kjell P Kjell Pernestal Dept of Physics phone ++46 18 18 31 66 Univ Uppsala fax ++46 18 18 35 24 Box 530 E-mail Kjell.Pernestal@fysik.uu.se S-751 21 UPPSALA, Sweden (try also kjp@forsmark.uu.se)
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