Clearing in the Gray's River Watershed, 1905-1996
study explores the patterns of land clearing in the 80,000 acre
Gray's River watershed in southwest Washington between the years
1905 and 1996. The exploration consists of three parts. First, a
description is presented of how the natural forest ecosystem functions,
including succession, the role of old-growth and second-growth in
the forest ecosystem, and natural and man-made disturbances to natural
this study presents original data documenting the patterns of forest
cutting within the Gray's River watershed. In 1905 there were an
estimated 65,000 acres of old-growth forest, but by 1996 only 1,476
acres, 2% of the old-growth remained in the watershed. Harvest levels
reached a climax in the late 1970's when, on average, 2,258 acres
of forest were removed each year.
this study assesses the current and future forest by considering
three different likely scenarios for timber harvesting. This work
concludes that disruptions of the forest ecology and the healthy
functioning of the watershed are likely to be permanent conditions
in the Gray's River watershed.
Between Snapshot & Composite Change Data
study evaluates how spatial and temporal data obtained from historic
map evidence function in two change detection applications that
focus on the snapshot and composite data models.
snapshot method is not conducive since it is only temporal coincidence
that is being queried, not causation as defined in the composite
model with a temporal topology that defines begin and end events
for database states. The capacity of the snapshot model is extenuated
with the use of temporal joining. This study demonstrates the use
of temporal joining with an example describing changes to surface
water in Portland, Oregon between 1880 and 2000.
composite method integrates time data and space data into a database
that functions with various object states separated by events. The
example demonstrating this capability is the Gray's River watershed
forest cover. Even though the composite model demonstrated uses
cartographic time in a static rollback form, it is useful for determining
how events changed object states based on map evidence.