Dear Patrick At 20:50 06.06.98 -0700, you wrote: >I have travelled extensively through Germany, Austria, and Switzerland and I >have never seen single tree selection in coniferous forests. In Switzerland about 9% of the forest area is managed by the single tree selection. We call it Plenter forest. Today this is mainly in the zone of silver fir-Norway spruce-Beech forest. But it works also in higher altitudes in pure spruce forests and in mixtures with larch and cembran pine. In northeastern Switzerland they practice it in forests with up to 50 % of broadleaved species on flat terrain where not proctection function in the proper sense is needed. We have research plots in all those forest types. If you did not see it: please come again. I'll show it to you. This is an invitation! >In the >mountains (Alps), the most common method of harvest is by skyline carriage. >This is a form of small group selection or mini-clearcuts along the path of >the skyline. It could also be called a form of shelterwood harvest. The >point is, these forest types regenerate best when full sunlight is allowed >to reach the seedlings. Single tree selection cannot provide this >requirement. This is not correct. Even on steeper slopes, where skyline carriage is used, this can be a single tree selection system or a group selection system. Most of the trees are much more shadow tolerant than we think. Two weeks ago I saw in the Netherland very rich natural regeneration of Douglas fir under a closed canopy of Douglas fir. They want to treat these forest with a selection system and I am shure they will manag ist. >In Switzerland, where they say clearcutting is not allowed, they get around >it by leaving some trees, say 20% of the stand, and calling it shelterwood, >when the new trees have greened up the site the remaining mature trees are >removed. This is essentially clearcutting. No, this is not. 1. There is much more than 20 % of the trees left, when they do what you call a shelterwood cut. 2. In a clearcut as we understand it, the stand is removed completly. In the selection or group selection system or perhaps better in the continuous cover system the remaining trees have are left on the site as long as possible. 3. We are not talking about mature trees. This is a subjective, anthropocentric term) This is a word I don't like because it suggests overmaturity or immaturity of a forest. How can one pretend to know this of a tree or a stand? Big trees are only removed when the regeneration is needed on a certain place. The aim ist to get a contiuous, well structured forest. > >>In the South West of Germany the allowed area for clearcuts has been >>reduced to 1 ha (2.5acres). If you want to exceed this you have to apply >>for a permission. > >1 ha is still a clearcut. The reason for the small size is mainly aesthetic >and subjective and has nothing to do with silviculture. All over the world, >foresters are being required to adopt harvesting and silvicultural systems >that are not optimal for regeneration due to public opinion that is based on >aesthetic and conjectural opinion. At least 1 ha of clearcuts seems to me much better than 10, 20 or even biger. In Europe and especially in Switzerland you will never find clearcuts in the size of clearcuts in Canada or the USA. The reason for not doing clearcuts is not asthetic and subjective. The reason for doing selection cuts is to maintain a contiuous cover. This is to maintain a continuous protection function where this is needed on steep slopes. And this is in big part of Switzerland the case where in the valley below the forest are villages, traffic infrastructures, tourisme etc. Thus the decision which silvicultural system has to be applied is a management decision and not based on a subjective public opinion. And by the way: Selection forests or even forests treated by a selective thinning (not identical with what you understand by this term) are quit close to a sustainable forest management in a fairly broad sense. >Don't get me wrong, I'm not against >single tree selection where it makes sense silviculturally, but this is in a >minority of forests. I do not agree with this. I'm shure that there are much more possibilities and on a big part of our forests. It has to be a management decision where to practice single tree selection. And I am convinced that it would be also possible in a lot of your forests, even in so called old growth (which is also a anthropocentric, subjective term). Selection cutting would be possible from a ecologial point of view in a big part of our forests, not only in a minority of them. I am also convinced that it is a economicaly interesting management system. This can be shown by real data from a lot of forest management units. If you really want to know more about this - one can also just close his eyes and his mind, that one does not see what he doesn't want to see - you should come again. I will show a a lot of examples and I'am shure Marc would do the same and other colleagues through Europe too. There are many examples of this. Best regards Andreas ********************************************************** Andreas Zingg Dipl. Forsting. ETH ¦ Research Forester Eidg. Forschungsanstalt für ¦ Swiss Federal Institute Wald, Schnee und Landschaft ¦ for Forest, Snow and Land- WSL ¦ scape Research WSL CH-8903 Birmensdorf ¦ CH-8903 Birmensdorf Schweiz Switzerland ---------------------------------------------------------- Tel. ++41 +1 739 23 35 Fax ++41 +1 739 22 15 E-mail andreas.zingg@wsl.ch
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