Ecological succession as a criterion for the selection of urban trees /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1992.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | This dissertation determines the value of successional stage as a criterion for selecting urban trees. Tree inventories were obtained from thirty cities in northeast and north central United States. The cities were then classified by potential natural vegetation (PNV), forest cover type, and eco-region. Tree inventories were then contrasted and compared to the potential (predicted) vegetation. It was found, that in cities where the potential natural vegetation type was forest, the species predicted were different than those existing in the urban areas. Maple species predominate and there was an absence of the predicted beech, oak species, and hickory species. Cities that were classified as having a PNV of grassland or prairie had tree species where none where predicted. Hills' numbers (NO, N1, N2) were calculated as a measure of the diversity of the city tree species. The resultes were an average of 58.67 species (NO), 9.08 very abundant species (N2), and 15.55 abundant species (N l). These numbers indicate a low species diversity. A N2 above 12 is recommended based upon the results of this study. Six cities had a N2 above 12 Individual species were then classified by longevity, size class, growth rate, and successional (seral) stage. Contingency tables were constructed and seral stage contrasted with the other categories. Chi-square tests of independence were run. In all cases where categories failed to be independent gamma, a measure of association, was applied to the tables. It was found that as seral stage got later longevity and size class increased, while growth rate decreased. The species were also cross-classified by value class based upon the location of the city. The same tests were run. For six of the ten value classes the classifications failed to be independent. Of these, all exhibited a mild tendency to increase in value class as seral stage got later. Species recommendations were made for each city. Short lists, comprised of species selected using seral stage as a criterion, were compiled for this purpose. A separate list was constructed for each city. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Forestry." |
| Physical Description: | ix, 177 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |