Saturday, May 21, 2011

Clear cutting &Silvicultural Systems

Young seedlings are establishing in the clear cut forest in the foreground while the back ground shows a large clear cut. Clear cuts in forests in BC tend to generate negative reactions from the public. Clear cuts in the landscape tend to give a feeling that there is something amiss. Foresters, the Government and forest corporations tend to dismiss these impressions as layman's reactions.

The professional explanation to counter concerns usually follows the following lines. Clear cutting is a legitimate silvicultural system in forest management. A silvicultural system is defined as the tending process by which the forest is removed and replaced by a regenerated forest. There are four general types of silvicultural system. Clear cutting silvicultural systems involve the complete felling of an area of forest, harvesting and regeneration, often by planting seedlings within a short space of time. Shelterwood silvicultural systems involve gradual removal of the forest in two or more fellings over a period of years. The new forest establishes under the reduced cover. The third type is selection silvicultural systems that involve a gradual removal of trees and regeneration that occurs continuously without creating large visible openings in the forest. An uneven aged forest with a range of ages and sizes of trees remains standing at all times. Finally there are coppice silvicultural systems that are applied to trees such as willows and poplars that tend to sprout new shoots from cut stumps.

Those with green leanings will favor selection silvicultural systems. However, selection silvicultural systems cannot be applied to all forests. Some species of trees will not regenerate and grow in the shade of other trees. Often trees of this type grow in forests that have fires or other natural disturbances that create large openings and they are adapted to become established in the open. Some areas of forests have root rots and other diseases that can be exacerbated by shelterwood and selection silvicultural systems.

You need all the silvicultural systems to manage a forest and clear cutting needs to be one of them. Discussion by folk from the BC forestry establishment on clear cutting usually ends there, but the unease about clear cutting remains. When lots of folk feel uneasy about something, there is usually some justification that not be immediately evident.

The BC forestry establishment has responded to this unease by inventing a completely new kind of silvicultural system called the variable retention silvicultural system. It involves leaving some individual trees or patches of trees within the area to be harvested. The idea is to introduce some diversity of ages and leave some islands of older growth to help accommodate biological diversity. Even dead or dying trees can be left standing to provide habitat for woodpeckers and cavity nesters. There is a legitimate intent to accommodate biological diversity but there is also a political intent to try to make clear cutting more acceptable.

Supporters of the variable retention silvicultural system usually make no attempt to place this supposedly new eco-forestry silvicultural system within the existing classical scheme of clear cutting, shelterwood or selection silvicultural systems. Shelterwood and selection silvicultural systems were first developed by European foresters led by Gayer ( 1880, 1886) with the intent of having systems that were more akin to natural indigenous forests. They were practicing what is now called eco-forestry. A large variety of shelterwood and selection systems have been used and adapted by foresters to produce variable forest ecosystems. Considerable local knowledge and skill is required and some even incorporate long term treatments of whole forest valleys to reduce windthrow. BC's supposedly new variable retention silvicultural system is little more than clear cutting with a politically correct excuse.

In BC, most forest harvesting is clear by cut and there are few examples of other silvicultural systems being applied successfully. Clear cutting is usually the least costly method of harvesting and requires less skill and local knowledge than shelterwood or selection systems. A silvicultural system is a system of tending a forest. The context is one where there is professional forester with responsibility and some freedom to manage a specific forest. In the case of shelterwood and selection silvicultural systems, the forester would have gained experience from a predecessor and would put considerable effort into passing that information on to his replacement. Unfortunately no such system of local professional forest stewardship exists over public forest lands in BC.

The main reason for having most of BC's forests in public ownership was to enable the trustee, the BC Government, to ensure a wise system of forest stewardship. Instead, BC Government administrations have created a political system of entitlements to BC public forests. Government partnered with commodity producing forest corporations in a scheme of industrial forest management that is imposed on the forest. It follows the industrial assembly line concept. Clear cutting is the low cost, low skills fit for the model.

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