Open Access Thesis
Trees--Iowa--Black Hawk County;
This study investigates the history and role of the native forest in an urban area of about 100 square miles, encompassing the cities of Waterloo, Cedar Falls, and Evansdale in Black Hawk County, Iowa. It examines various human influences in an attempt to determine how important each has been in preserving or destroying the natural forest.
The original forests in the study area were concentrated along the rivers and adjacent bluffs. The most serious impacts to the upland forests have been agriculture, residential and commercial development, whereas the floodplain forests have been most affected by industrial expansion, gravel mining, flood control and highway projects. Overall, from 1855 to 1983, 70% of the forest loss was caused by agriculture and logging, and 30% by activities related to urban development.
A detailed analysis was performed using six aerial photo sets from 1937 through 1983, in order to determine more precisely the changes in woodland and their causes. Forest areas were designated as either dense (75-100% canopy cover) or open (5-75%), and acres of forest loss were measured and assigned to nine possible causes.
In the 1930's, patches of dense and open forest were equally prevalent in both upland and lowland areas. But the upland woods gradually became more open as development took place within them, while lowland forests became thicker and more extensive due to diminished grazing.
Over the 46-year period, forest loss was 1.7 times greater than forest regeneration. The greatest cause of total woodland loss was flood control, followed by agriculture, gravel mining, commercial/ industrial development, and highway construction. When only dense woodland was considered, flood control and gravel mining were the most prominent causes, followed by highway construction, and commercial/ industrial development. The predominance of flood control reflects a major effort under way over the last 20 years. The highway work in progress since the end of the study period, however, has now made highway construction the greatest cause of forest destruction.
Private actions were the predominant factors in forest loss until the mid-1960's, but since then, actions by the public sector (primarily highway and flood control projects) have surpassed them.
Forest preservation through parks has been much more effective in floodplains than in the uplands, partly because floodplains are less attractive for development, and partly because the uplands were urbanized during a time when cities were not interested in acquiring natural areas for parks (the 1950's and early '60's). County and state parks specialize more than city parks in the preservation of natural forest areas. An analysis of city parks revealed that significantly more woodland is present in donated parks than in purchased parks.
Knowledge of the causes of woodland loss and preservation should prove useful to planners and citizens interested in preserving their natural woodland heritage.
Year of Submission
Master of Arts
Department of Geography
C. Murray Austin, Chair
1 PDF file (viii, 178 pages)
©1988 Alice Christine Robbins
Robbins, Alice Christine, "Native trees in an urban area: A case study of the Waterloo metropolitan area Black Hawk County, Iowa" (1988). Theses and Dissertations @ UNI. 941.