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Group Selection Harvests, Patch cuts. Objectives. To understand the concepts behind group selection To understand how to set-up group selection cuts in the field. Multi-cohort Management. Age structure Species composition Disturbance regime . Partial disturbances. dead. Tree height.
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Objectives • To understand the concepts behind group selection • To understand how to set-up group selection cuts in the field
Multi-cohort Management • Age structure • Species composition • Disturbance regime
dead Tree height Full Sun Overstory density Full shade Stand Age
Tree height Full Sun Overstory density Full shade Stand Age
EDGE UNCUT OPEN GAP
Estimate of impacted area y x x+y
Area lost = x2 Total area impacted = (x+y)2 Area with reduced growth (edge) = [ (x+y)2 - x2] or [2xy + y2] y x x+y
Yield Time Yield
Total yield Yield Time
Regeneration • Natural • Planting
Slash disposal • Pile and burn? • costly
Veg Management • Difficult • Usually manual
Precommercial thinning • Inefficient • Can only cover part of the area
Equipment • Skidders • Cable