FORESTRY: ENVIROTHON
About 30% of the world is forested today, but the ratio
between forest and population varies immensely.
More than one half of the world's softwood timber (the
major forest product) comes from North America and
Europe—an area with only a fourth of the world's
population.
The forested area of the United States has shrunk in
300 years from about one half to one third of the total
land acreage.
The United States and Canada share 16% of the world's
forests; the former Soviet Union contains 21%, Africa
has 20%, and Latin American has 24%.
FOREST PRODUCTS
FORESTS: ASSESSING
THE RESOURCE
Depending on “what you want” from a forest will
determine what you will and won’t do to it……
Minimally even if you were to preserve the forest
you have to know what’s there. That inventory could
be the trees (and all other life and non-life there:
smaller plants, animals, bacteria, fungi,
soils, hydrology, etc.)
WHAT SPECIES?
Measuring the diversity or species composition of your forest is
almost always a basic and prime concern. One way to identify trees
particularly if the species are new to you is to use a KEY. Some items
that appear in keys that are useful to know are:
Leaf shape
Branching pattern
Leaf type
WHAT SPECIES?
Other useful characteristics to help identify trees are:
Bark characteristics
Fruits
Flowers
WHAT SPECIES?
Tree form
Smell (leaves, bark)
Leaf tips
Leaf bases
Site
Buds, twigs
ETC…….
Tree diameter and heights using
Biltmore stick/Merritt hypsometer
TREE DIAMETER (DBH):
D-tape
measure at
4.5 ft from
ground….
TREE HEIGHT (TOTAL):
Suunto Clinometer
Two measurements:
-One at ground level
-The other the very
top of the tree
HEIGHT=TOP MEASUREMENT – BOTTOM MEASUREMENT
(BE CAREFUL: THERE ARE + and – READINGS YOU CAN GET!)
TREE AGE (at breast height):
Increment corer
TREE AGE (at breast height) CONT’D:
We bore the tree at breast height
4.5 feet from the ground….
TREE AGE (at breast height) CONT’D:
You can bring the cores back to the lab, mount and sand them
and do some DENDROCHRONOLOGY (study of tree rings)..
POINT SAMPLING
SILVICULTURE
“the art and science of controlling the establishment,
growth, composition, health, and quality of forests and
woodlands to meet the diverse needs and values of
landowners and society on a sustainable basis through
the application of silvics”
SILVICS:
….the life history and general characteristics of forest trees
and stands, with particular reference to environmental factors….
SILVICULTURE CONTROLS:
Stand composition
Stand density
Restock underproductive areas
Protection and salvage
Control rotation length
Facilitate the harvest, management, and use of the forest
Protection of the site and indirect benefits
SILVICULTURAL SYSTEMS
CAN BE DIVIDED INTO THREE BROAD GROUPS:
REGENERATION SYSTEMS
Uneven-aged systems
Even-aged systems
Group or Individual Selection systems
Clearcut systems
Coppice systems
Seed tree systems
Shelterwood systems
INTERMEDIATE CUTS
Thinnings, cleanings
SALVAGE/PROTECTION
Clearcut
-usually INTOLERANT
trees regenerated
-create or promote evenaged stands
-best with light seeded
spp.
-trees are overmature
BE CAREFUL:
-Can promote shrubs
-can overexpose sensitive
sites
-slash can impair
regeneration.
-erosion on steep slopes
CLEARCUTS
In strips…..
or patches:
Jack pine clearcut
in Manitoba to
mimic natural fire
pattern
Coppice
You are ASEXUALLY
reproducing the forest:
stump sprouts
Seed Tree
The trees you leave as seed
sources should represent the
species you want and are the
‘best’ there….
What are the dangers to this
process?
Shortleaf seed tree (15 per acre)
SHELTERWOOD
Preparatory cuts
These may be one or several light cuts to
improve the vigor and wind firmness of
potential leave-trees to prepare for the next
cuttings. Establishment, regeneration or
seeding cut
Establishment, regeneration or seeding cut
This cutting, which may be the first cutting
in some unmanaged stands, is to provide
growing space for establishing regeneration
while maintaining shelter for developing
seedlings. Trees chosen to be retained after
this cut should be vigorous and wind firm.
Overstory removal cut(s)
Once regeneration is established and
stocking is acceptable, removal of the
sheltering overstory is a common option.
Alternatively, all or some of the sheltering
residual overstory can be permanently or
temporarily reserved from future cutting to
satisfy management objectives.
SHELTERWOOD
Shelterwood on Douglas fir in West (note slope of land)
SELECTION
single tree
Usually this and group are for TOLERANT trees and uneven-aged stand
SELECTION
single tree
Single tree selection : red spruce,
hemlock, and balsam fir
SELECTION
group
Group selection: old growth
spruce fir forest
INTERMEDIATE CUTS
Treatment of stand during part of the rotation not included
in regeneration period….
Intermediate cuts are used for:
-improve existing stand
-regulate growth
-provision for early
financial returns
If regulate growth then called thinnings
If regulate species composition: young stands: release cuttings
old stands: improvement cuts
If take branches off: pruning
INTERMEDIATE CUTS
Many types of thinnings:
Low (German)
Crown (French)
Selection
Geometric
Free
CROWN CLASSIFICATION
Low Thin
Trees are removed from the
lower crown classes
Mimics natural mortality
You can work in a range of
Thinnings:
A-B thin without risk of
reducing wood production
C-D stimulate growth of
remaining trees (not just
salvage)
CROWN THIN
Remove trees in middle and
upper crown classes
Most trees cut are Codominant
but can take out interfering
Intermediates or Dominants
Crown thinning favors nearly the
same trees as Low thins but
removes a few strong
competitors rather than eliminate
the weak (As Low thin does)
Crown thin is more flexible but
demands greater expertise…
SELECTION THIN
-Dominant trees are removed to stimulate lower crown classes
-Vigorous trees favored in Crown and Low are the very ones likely
to be cut here
-Be careful: limited use, could become High grading!
MECHANICAL THIN
Aspen stand in which 5 meter wide strips are removed to thin…
PRUNING
Very expensive and intensive BUT in
certain circumstances you could get more
money for the wood (no knots)
RELEASE CUTS/TREATMENT
Done when stand is young to remove species not desired…..
Pine stand above – releasing
pines by using brush saw on
undesirable species- the final result
is the bottom picture
IMPROVEMENT CUTS
BEFORE (LEFT) and AFTER (RIGHT) of HARDWOOD STAND
In Mississippi- get rid of poorly formed species or undesirable species and shrubs…