Silvics and Silvicultural Systems Flashcards
what is thinning
overcrowding of young stands
Crown thinning is removal of larger trees
low thinning is thinning from below
what is pruning
cutting lower branches for high grade logs (free of knots); higher densities at early stages may do the same job
what is sanitation cutting
removal of infected or attacked trees from the stand and leave the healthy trees to grow
what is silvics
- Involves understanding how trees grow, reproduce, and respond to environmental changes
- Study of the history of trees and forests
what is the general procedure for wood production
o logging operation involves cutting trees down (felling)
o sawing trees up into proper lengths bucking)
o dragging it over the ground (skidding)
o dragging them to a road where it piled for loading into a truck (decked)
what is whole tree harvesting (WTH)
drag whole tree to road and than construct bucking
What is stem only harvesting (SOH)
conduct bucking then drag stem to road
what are the differences between WTH and SOH
o Amount and size of materials (slash) left on the site
o Has implications for nutrients, habitat, and tree growth
what is Silviculture
- Art and science of controlling the establishment, growth, composition, and quality of forest vegetation for the full range of forest resource objectives
what is a silvicultural system
planned treatments during whole life of a stand designed to achieve specific stand structural objectives
specific harvesting regenerations, stand tending methods to get a predictable yield of benefits from the stand over time
what are even aged stands
o One age class, some two aged classes ins open stands
o Well defined canopy with uniform height
o Bell shaped diameter distribution
o Regeneration period is <20% of rotation length
what are uneven aged stands
o At least three age classes
o Differs in height age and diameter
o Uneven and highly broken/irregular canopy
o Inverted J form of diameter distribution
o Regeneration period occurs throughout entire rotation
what are even aged systems
clear-cutting
patch cut
seed tree
shelter wood
coppice
retention
what is clear cutting
Stand removed in one harvest; new even aged stands are regenerated after harvest with previously cleared block
Used to replace old stands with new vigorous stand ASAP
Stand tending operations are easily incorporated into system
Concerns: loss of old growth and environmental impacts
what is a patch cut
small areas cut
selection cut
what is seed tree
Entire cutting unit managed as it is with clear-cut systems
For designated time period those trees selected for supplying seed aren’t harvested
Trees left just for supply seed for next crop
Seed trees are harvested in removal cut once regeneration established
Uniform and group seed system
what is shelter wood
Old stand removed in series of cuttings to promote even aged new stand under shelter of the old one
central feature is that over storey leave-trees are left on site to protect regenerating understorey until understorey doesn’t need protection
what is coppice
Main regeneration method is vegetative sprouting of either suckers form the root system of trees or shoots from the cut stumps
what is retention
Aggregate retention
Dispersed retention
what is the uneven aged system called
selection
what is selection
mature timber is removed either as single scattered individuals or small groups at short intervals
Repeated indefinitely where in even aged stand is maintained
what is variable retention
Borrow aspects of both even and uneven aged regeneration cutting systems
- min 50% cut block or one tree length
- irregular retention boundary gives forest influence
-regeneration in open area even aged from natural seed or planting
what are fundamental management techniques for variable retention
reduce ecological impact of harvesting by retaining elements of stand and forest structure
Reduce aesthetic impact of harvesting to gain public acceptance
