FOR200H1 Lecture Notes - Lecture 9: Soil Structure, Pioneer Species, Electronic Body Music
26 May 2018
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Monday, December 7, 2015
FOR200 - Lecture 9
Forest Harvesting
-A general term for the removal of biomass from the forest for utilisation; comprising
cutting, sometimes further initial processing (topping and trimming), and extraction
-Different for privately owned forests - then loggers pay for stumpage
•but we focus on logging on crown land
-Sometimes trees are cut from the base, and sometimes there is whole tree logging
(the whole biomass is utilised and the tree is pulled up from the root
Manual and mechanic harvesting
-Traditionally everything was done manually
-Now, most things are mechanised
-but that is dependent on topography
-this makes the process safer and cheaper, but makes it so that there’s less people
working in the forest
Risks associated with harvesting
-Stresses the forest by opening up the canopy, increasing light, temperature, wind
speed and decreasing relative humidity
-There are some species found in the acadian forest that cannot survive living in a
clearcut
-All the nutrients are found in the biomass so the harvesting exports nutrients out of
the forest
-you can create conditions for erosion, landslides, etc.
-Soil damage, compaction, erosion, silt and sedimentation
-people try to combat this by transferring nutrients to the harvesting sites
-heavy machines can cause a lot of damage
!1
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Monday, December 7, 2015
-Injuries to residual trees, seedlings and saplings, fine roots and scarring
-Adverse effects on ecosystem - habitat destruction, fragmentation
Harvesting Systems
Harvesting is a type of silviculture
Silviculture is the practice of controlling the establishment, growth, composition, health,
and quality of forests to meet diverse needs and values.
Even Aged Silvicultural Systems:
-Over 80% of the trees harvested in Canada are harvested this way
-Clearcutting systems, involving the removal of all trees
-this is used 90% of the time
-it’s also usually mechanised
-you plant in tree seedlings from a greenhouse and leaving one old growth tree
behind to reforest the whole forest
-Shelterwood systems, involving the retention of an overstory of mature trees while an
understory of regeneration becomes established; such an understory is called
advance growth and often occurs naturally in old forests;
-you’re essentially cutting the trees down in two stages
-you take 50% of the trees and then come back for the rest later
-you can moderate some of the microclimatic changes
-it is critically necessary for saplings to grow a little
-you go back after 20 years and cut the second half of trees
-so you have 2 age groups of trees
-it’s like a delayed clearcut
-the seeds that come from the trees that are left behind are adapted to the
conditions in which it will live (genetic advantage)
-Seed-tree systems, involving the leaving of a selected number of individual or groups
of trees of superior form together with a receptive seedbed;
!2
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
A general term for the removal of biomass from the forest for utilisation; comprising cutting, sometimes further initial processing (topping and trimming), and extraction. Different for privately owned forests - then loggers pay for stumpage: but we focus on logging on crown land. Sometimes trees are cut from the base, and sometimes there is whole tree logging (the whole biomass is utilised and the tree is pulled up from the root. This makes the process safer and cheaper, but makes it so that there"s less people working in the forest. Stresses the forest by opening up the canopy, increasing light, temperature, wind speed and decreasing relative humidity. There are some species found in the acadian forest that cannot survive living in a clearcut. All the nutrients are found in the biomass so the harvesting exports nutrients out of the forest. You can create conditions for erosion, landslides, etc. Soil damage, compaction, erosion, silt and sedimentation.
