Timber harvesting is the cutting and removal of trees. Harvesting activities should be conducted to ensure long-term maintenance of water quality. Using the Forest Water Quality Guidelines in a timber sale contract protects your property and helps ensure availability of forest resources for future generations.
HARVESTING SYSTEMS
Generally, harvesting systems fall into three categories: ground-based,
cable and aerial. Choose the harvesting system best suited to site conditions,
cost-effectiveness and your management objectives.
Ground-based Systems
Ground-based harvesting systems are typically used on gentle terrain,
stable soils and in areas with adequate access. Ground based systems are
generally used on slopes less than 40% and skidding distances less than
600 feet for tracked machines and 1200 feet for rubber tired equipment.
Although used infrequently, harvesting by horses can be used in smaller timber. Requires relatively flat, level ground.
Rubber tired grapple skidder: The most commonly used and least expensive system. Skidders may cause excessive soil damage (i.e. compaction) if operating in wet conditions.
Tracked grapple dozer: Suitable for use on moderate slopes. May cause less damage than rubber tired skidders when soils are wet.
Feller-buncher: Mechanical harvesters can minimize damage to residual trees, water & soil.
Delimber/Processor: This equipment begins the manufac turing process in the forest by cutting trees to exact lengths.
Cable Systems
Cable harvesting systems are generally used on steep slopes, broken topography or where ground-based equipment cannot operate. Cable harvesting systems are typically used on slopes in excess of 40% and yarding distances of 1000 feet. They lift logs off the ground and move them to a landing where they are loaded and hauled away.
Cable harvesting system using a tower and drum assembly.
A high-lead or skyline logging system.
Aerial Systems
Where road construction, unstable terrain and steep slopes preclude standard harvest methods, aerial harvesting systems can be effective. Aerial harvesting systems are also used for high-value selective logging and in areas where aesthetics are important.
Photo at right shows a spruce salvage sale using helicopter to haul the logs to a landing. Aerial harvesting systems are the most expensive.
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