Transcript Forest Managementx

Forest Management: Issues with
harvesting trees for wood-based
products
Area of forest Ecosystems
• About one half of the forests that covered the
earth are gone
• Each year another 16 million hectares
disappears
• Today, forests cover ~1/4 of world’s total land
area
Some definitions…
• Ecological (or ecosystem) services: Natural
services or natural capital that support life on
the earth and are essential to the quality of
human life
• Economic services: resources and
opportunities available that support the
functioning of the world’s economies
Importance of Forests
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Ecological services:
Support energy flow and nutrient cycling
Reduce soil erosion
Absorb and release water slowly
Purify water and air
Influence local and regional climate
Store atmospheric carbon
Provide numerous wildlife habitats
• Forests remove _____ from and add _____ to
the atmosphere.
a.
oxygen . . . carbon dioxide
b. nitrogen . . . oxygen
c.
carbon dioxide . . . sulfur dioxide
d. carbon dioxide . . . oxygen
e. nitrogen . . . carbon dioxide
Importance of Forests
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Economic Services:
Fuelwood
Lumber
Pulp for paper
Mining
Livestock grazing
Recreation
Jobs
• Which of the following is not an economic
service provided by forests?
a.
purification of water and air
b. fuelwood
c.
lumber
d. mining
e. jobs
Types of Forests
• Old-growth: uncut or regenerated forest that
has not been seriously disturbed by human
activities or natural disasters for at least
several hundred years
– <10% - 22% of world’s forest
From Scientific American…
• According to a study done in 2008, “Old
growth forests in the U.S. Pacific Northwest as
well as Canada and Russia consume 8-20% of
the global terrestrial carbon sink, or roughly
440.9 million tons of carbon per year”
• We release 1.8 billion tons through
deforestation and crop-clearing a year…
Remaining Old Growth Forest – each
dot represents 25,000 acres
• Second-growth
• A stand of trees resulting from natural
succession (the return of species to an area
that has been disturbed)
• Tree farm or plantation:
• Farm of trees – all roughly the same age and
generally one or two species that are
harvested by clear-cutting as soon as they are
commercially valuable
How are trees harvested?
• Selective cutting: harvesting intermediate-age
or mature trees singly or in small groups
– Reduces crowding, disease, encourages growth of
younger trees
• Clear cutting: Removes all trees in an area
• Strip cutting: clear cutting a strip of trees with
the corridor narrow enough to allow natural
regeneration within a few years
Which of these methods do you think
is the most damaging and why?
• Selective Cutting
• Clear Cutting
• Strip Cutting
• Certified Sustainably Grown Timber must
a.
eliminate dead trees within the forest
b. must include a minimum number of roads
within the forest system
c.
ensure that cutting has not exceeded longterm forest regeneration
d. All of the above.
e. None of the above.
Clear cutting in Washington
Issues with Deforestation
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Decreased soil fertility due to erosion
Runoff of eroded soil into aquatic systems
Extinction of species with specialized niches
Loss of habitat
Regional climate change from clearing
Release of CO2 into the atmosphere
Acceleration of flooding
Cattle pasture in the Brazilian Amazon
Solutions
We can use forests more
sustainably by
emphasizing:
Economic value of
ecological services.
Harvesting trees no faster
than they are replenished.
Protecting old-growth and
vulnerable areas.
Figure 10-12
An example of the 3 lenses of true
sustainability
• Less than 1.5% of original tree cover remains intact
• Why????
Deforestation in Haiti
• Haiti is still ranked as the poorest country in the Western
Hemisphere – 80% live below the poverty line, 54% in
abject poverty
• Haiti’s electricity sector only covered 10% of its population
in 2006
• Wood became and continues to be the principal energy
source in Haiti - accounting for 70% of energy consumption
• Deforestation leads to erosion – an estimated 6,000
hectares of soil lost each year to erosion (1 ha = 10,000 m2
= 2.47105 acres)
• Also exposure to natural disasters – hurricanes, landslides,
etc.
• MIT researcher Amy Smith has been working
with Haitians in developing a way to make
charcoal for cooking from the waste fibers of
sugar cane
• Burns cleaner than wood charcoal
• Saves trees, reduces lung disease and
premature deaths
Managing Forests
• Forests on federal and state lands are managed
according to multiple use doctrine
– i.e. land is available for recreation and maintains a healthy
forest ecosystem in the midst of forest harvest
• Good news: Forests in the US cover more area than
they did in 1920
– Considered to be the great environmental story of the US
– US timber companies and conservation organizations are
working together to protect large areas of forest
– Every year more wood is grown in the US than cut
– Protected forests make up about 40% of total forest area
Forest Management Cont.
• Fire management – controversial
• Are all forest fires bad???
• Fire suppression can lead to highly destructive crown
fires from the accumulation of brush and smaller trees
• Also, many species need fires to survive
– Ex: Several species of pine trees release their seeds only
after the fire heats its cone to melt their waxy seals
– Blazing star, wild lupine, sandplain gerardia (endangered
species) also need fire to reproduce
– Fires return nutrients quickly to the soil (oak trees rely on
this)
– Also help open up and maintain meadow habitats and
grasslands
• Solutions:
• Controlled burns or prescribed fires : start small,
contained surface fires to clear out brush
• Allow fires in public lands to burn as long as the
fires do not threaten human structures and life
• Healthy Forests Restoration Act: (2003) allows
timber companies to cut down economically
valuable trees in 71% of the total area in national
forests in return for clearing away smaller brush
• Many fire scientists believe this will actually
encourage large fires as timber companies
remove the larger fire resistant trees and leave
behind slash piles and smaller trees/brush