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The preceding pages provide an
overall description of each scenario. In the
pages that follow the emphasis is on amongscenario comparisons. Six major components of the landscape are examined: natural
vegetation, riparian areas, agriculture,
forestry, urban areas, and rural residential
development. For each, we describe key
landscape characteristics (e.g., housing
density, acres of wetlands) as well as the
assumptions and methods used to generate
the landscape patterns represented in the
scenarios. Some landscape components
involved complex computer models. For
example, changes in agricultural lands are
derived from a land allocation model
designed to mimic the crop selection
decisions made by agricultural producers.
Input data included the suitability of the
land for different types of crops, availability
of water and crop requirements for water, a
crop’s expected cost and returns and, for the
Conservation 2050 scenario, environmental
considerations, such as pesticide and
fertilizer requirements. For other landscape
components, on the other hand, the process
of landscape generation was relatively
simple and direct. For example, in Plan
Trend 2050 and Development 2050, the
distribution and types of natural vegetation
in the lowlands are determined largely by
default. That is, the natural vegetation that
occurs circa 1990 remains through 2050 as
long as it is not converted to urban or rural
residential development or modified by
agriculture or forestry land uses.
Scenario Comparisons
PNW Ecosystem Research Consortium
S
N
Map 29.
Pre-EuroAmerican Scenario
Note: legend above right pertains to all maps on this
and facing page. For an explanation of the crossreferencing of this legend with historical classifications,
see pp. 162-65 of Appendices.
Unknown
Rural non-vegetated unknown
Urban non-vegetated unknown
Forest closed mixed
Forest closed hardwood
Light duty roads
Secondary roads
Primary roads
Railroad
Rural structures
Residential & commercial
Industrial
Commercial/Industrial
Commercial
Residential > 16 DU/ac
Residential 9 - 16 DU/ac
Residential 4 - 9 DU/ac
Residential 0 - 4 DU/ac
Built features
Conifer Woodlot
Christmas trees
Orchard
Urban tree overstory
Turfgrass
Irrigated perennial
Bare/fallow
Pasture
Late field crops
Hayfield
Field crop
Burned grass
Grass
Row crop
Sugar beet seed
Radish seed
Mint
Hops
Double cropping
Berries & vineyards
Nursery
Grains
Irrigated annual rotation
Grass seed rotation
Hybrid poplar
Agriculture
Wet prairie
Wet shrub
Oak Savanna
Flooded/marsh
Natural shrub
Natural grassland
Upland Forest semi-closed hardwood
Forest closed conifer older than 200 yrs.
Forest closed conifer 81 - 200 yrs.
Forest closed conifer 61 - 80 yrs.
Forest closed conifer 41 - 60 yrs.
Forest closed conifer 21 - 40 yrs.
Conifers 0 - 20 yrs.
Upland Forest semi- closed conifer
Unknown
Barren
Snow
Topographic shadow
Permanent lentic water
Stream orders 5 - 7
Main channel non-vegetated
Upland Forest open
Natural & native vegetation
Upland Forest semi-closed mixed
Water
ater & physiographic features
Map 30.
Land Use / Land Cover ca. 1990
Scenario Comparisons
J. Baker D. Hulse
Willamette River Basin Atlas
2nd Edition
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It is impossible to predict with complete accuracy exactly where land conversions will occur, from natural vegetation to human use, or between different types of human use (e.g., agriculture to rural residential, or low density to high
density housing), or from human use to natural vegetation, in the case of ecosystem restoration. For example, we cannot
say for certain that houses will be built on parcels “a,” “b,” and “c,” only that houses are more likely to be built on
certain types of land (e.g., with gentle slopes and adequate drainage) and in certain areas (e.g., with ready access to
Map 31.
Conservation 2050
Map 33.
Development 2050
will be converted. The methods used to generate and depict the 2050 landscapes work in a similar manner. Thus, the
scenarios cannot be viewed as maps of exactly what the landscape will be like in the future if the specified policies are
implemented. However, they bracket a plausible range of the overall patterns likely to occur under the corresponding
scenario assumptions.
major roads and employment centers). There is an element of chance that affects whether any particular suitable parcel
Map 32.
Plan Trend 2050
TRAJECTORIES OF CHANGE
Maps 29-33. Scenario Comparisons
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