Transcript Multiple use

Maintaining Terrestrial Biomes
• In the United States, the government
manages public lands including forests,
parks, and refuges.
• Their use varies from resource extraction
to farming to recreation.
• Multiple use lands include those in the
– National Forest System
• Managed by the U.S. Forest Service
– National Resource Lands
• Managed by the Bureau of Land
Management
– National Wildlife Refuges
• Managed by the U.S. Fish and Wildlife
Service
Permitted activities include:
• logging
• mining
• oil and gas extraction
• livestock grazing
• farming
• recreation
• How should they be managed? Who
should be permitted to use the lands?
Ongoing controversy…
Examples:
• Northern Spotted Owl
– Endangered species
– Habitat: Old-growth forests
Of pacific northwest
Versus:
• Jobs and harvesting resources: the oldgrowth trees are of high commercial value
Should we “drill baby drill”???
ANWR
• Some public lands are restricted in use
– National Park System
• Managed by the National Park Service
(NPS)
• First established National Park???
– Only camping, hiking, fishing, and boating
(motorized cars/boats are allowed)
Yosemite
The Grand Canyon
Denali
Arches
Volcano
Carlsbad Caverns
Big Bend
Glacier
The Badlands
Great Smokey Mountains
• Other public lands are very restricted –
meant to be preserved in their natural
condition
– National Wilderness Preservation System
• Established by the Wilderness Act (1964)
• Managed by multiple agencies (BLM,
USFWS, USFS, and NPS)
– National Wild and Scenic Rivers (1968)
– Non-motorized recreation ONLY
Types of Forests:
• Old-growth: has not been cut/disturbed by
human activity for hundreds of years.
– Example: Redwood
Forest
• Second-growth: forest that has grown
back after it had been cut/removed by
human activities.
• Since 1600, 90% of the virgin forests that
once covered much of the lower 48 states
have been cleared away. Most of the
remaining old-growth forests in the lower
48 states and Alaska are on public
lands. In the Pacific Northwest about 80%
of this forestland is slated for logging.
– Global Deforestation Lecture, The University
of Michigan: Global Change
• Tree plantation or tree farm:
– Monoculture (example: Christmas tree farm)
• (example: apple orchard)
Types of Forest Management:
• Even-aged: Maintaining trees at about the
same age and size (tree plantation)
– Goal: economically desirable species
• Uneven-aged: Maintaining a variety of
trees at many ages and sizes
– Goal: sustainable production
Types of Tree Harvesting:
• Selective cutting: medium or mature trees
in uneven-aged stand cut singly or in small
groups.
• Shelterwood cutting: remove all mature
trees in an area in a series of cuttings.
– First cut: mature trees (mostly canopy trees)
– Second cut: more mature canopy trees but
leaves a few mature trees to “shelter” the
young trees (which are shade tolerant)
– Third cut: remove remaining mature trees now
that the younger ones are growing to maturity
• Seed-tree cutting: harvesting nearly all
trees in one cutting, but leaving a few
uniformly distributed seedlings.
• Strip cutting: removes all trees in an area
in a single cutting (in a strip)
• Clear cutting: removes ALL trees in a
single area. MOST devastating to an
ecosystem; causes massive soil erosion if
done on sloped land.
Types of Forest Fires
• Surface: Usually burn only undergrowth
and leaf litter on forest floor.
• Ground: surface fire that goes
underground (most common in areas that
contain peat – northern peat bogs).
Difficult to detect and extinguish.
(peat bog)
• Crown: May start on ground but eventually
burn up whole tree and leap tree-top to
tree-top.
• MOST DANGEROUS!
Prescribed burning:
• Controlled burning of flammable materials
to prevent build-up of fire-prone debris.
• Used to prevent major fires in populated
areas, but remember, not all fire is bad –
some plants and even biomes need fire to
regenerate.
– Grasslands and Chaparral
– Aspen trees in Yellowstone
Healthy Forests Initiative (HFI):
• Passes by Congress in 2003
• Timber companies are allowed to cut down
economically valuable large trees in return
for clearing away fire-prone underbrush.
• Removes large, more fire-resistant trees.
• Leaves fire-prone slash: unwanted
branches, tops, stumps.