Variable retention glossary and government resources

Variable retention : a relatively newsilvicultural system that follows nature's model by always retaining part of the forestafter harvesting. Standing trees are left in a dispersed or aggregated form to meetobjectives such as retaining old growth structure, habitat protection and visual quality.Variable retention retains structural features (snags, large woody debris, live trees ofvarying sizes and canopy levels) as habitat for a host of forest organisms. There are twotypes of variable retention:

Dispersed retention - retains individual trees scattered throughout a cutblock,
Aggregate (group) retention - retains trees in clumps or clusters.

The main objectives of variable retention are to retain the natural range of stand andforest structure and forest functions. With retention systems, forest areas to be retainedare determined before deciding which areas will be cut. This system offers a range ofretention levels. The system also provides for permanent retention of trees and otherstructures after regeneration is established. Variable retention can be implemented with arange of harvesting systems and can be combined with traditional silvicultural systemssuch as shelterwood or selection.

[Ministry of Forests -- Government of British Columbia]

Board of Forestry - General Information
Final Rule Language Variable Retention - 2003 (35K PDF), Final Rule Language

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Pressure-induced retention variations in reversed-phase alternate ...
A new model of chromatographic retention that appropriately accounts for this

Questionnaire Regarding State DOT Approaches for Dealing with ...
...(CA - the Department utilizes a variable retention percentage on progress

CLINICAL PHARMACOLOGY/BIOPHARMACEUTICS REVIEW
...demonstrating a highly variable retention of cisplatin at the tumor site.

Announcement of Publications - June 1998
A hierarchical approach to habitat modeling, with regard to variable retention,

Natural Connections > JERRY FRANKLIN BIO
Alternative silvicultural approaches to timber harvesting: variable retention

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