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ECONOMIC ANALYSIS OF URBAN TREE
REPLACEMENT DECISIONS
by Jessie L. Scott and David R. Betters
Abstract. Urban forest managers often are required to make decisions about whether to retain or replace an existing tree. In part, this decision relies on an economic analysis of the benefits and costs of the alternatives. This paper presents an economic methodology that helps address the tree replacement problem. The procedures apply to analyzing the benefits and costs of existing trees as well as future replacement trees. A case study, involving a diseased American elm (Ulmus americana) is used to illustrate an application of the methodology. The procedures should prove useful in developing economic guides for tree replacement/retention decisions.
A STRATEGY TO ESTABLISH TREES
AMONG HIGH-DENSITY HOUSING
by Hal St. G Appleyard
Abstract. High-density housing (HDH) ranks as one of the most hostile of planting environments. The best success rates are realized after the implementation of a planned tree-planting strategy. A strategy converts what is commonly addressed as an annual one-off task into an all- encompassing process of events, which when placed into a logical order provide optimal circumstances for ensuring successful tree establishment. The tree-planting strategy developed in Lambeth, United Kingdom, based on observations and consultation with users, has proved to reduce failure rates. It is possible to apply the principles of the strategy developed for HDH to the range of planting environments presented to the tree manager.
TREE CONDITION ASSOCIATED WITH
TOPPING IN SOUTHERN ILLINOIS COMMUNITIES
by Dean A. Karlovich, John W. Groninger, and David D. Close
Abstract. Twenty-seven percent of trees surveyed in southern Illinois communities showed evidence of topping. Topped trees were nearly 3 times more frequently classified as likely to fail structurally than those individuals not subjected to topping. Frequency of broken branches in the crown, evidence of insect or disease infestation, and cavities in the bole were also greater in topped trees. While the design of this study did not allow determination of a cause-and-effect relationship, increased incidence of conditions associated with tree failure was observed in topped versus nontopped trees.
THE EFFECT OF BIOBARRIER®
ON MYCORRHIZAE IN OAK AND SWEETGUM
by Karel Jacobs, Bill Rao, Brian Jeffers, and Donna Danielson
Abstract. The effect of Biobarrier® herbicide-impregnated barrier fabric (Reemay, Inc., P.O. Box 511, Old Hickory, TN 37138-3651) on mycorrhizae occurrence was assessed on established pin oak (Quercus palustris) and sweetgum (Liquidambar styraciflua) trees. Trenches were dug through 24 tree root systems, and in 12 of the root systems, trenches were lined with Biobarrier. Seventeen months later roots were collected from within and adjacent to the trenches. Microscopic examination revealed that ectomycorrhizae occurred on roots of all 12 oak trees, regardless of the presence or absence of the barrier fabric. Similarly, roots from all sweetgum trees, except for 1 control tree (no barrier fabric), had vesicular endomycorrhizae.
A PRODUCTIVITY TIMING SYSTEM
FOR TREE CLIMBING TRAINING
by Ronald E. Zillmer, Jeffrey L. Boeder, and Kevin G. Genich
Abstract. The City of Milwaukee Forestry Division manages more than 200,000 street trees and 120 mi (193 km) of landscaped boulevards. Tree pruning is a major operation that accounts for the pruning of more than 58,000 trees per year, with a majority of such work done by rope and saddle. Our program for current and newly hired employees consists of intense training during a 6-month probationary period. The cornerstone of this training program is based on building climbing proficiency and demonstrating the ability to prune a predetermined number of trees per day within certain size classes. To refine our climbing training program, we developed a unique productivity timing system utilizing a pruning study conducted by the University of Wisconsin-Stevens Point in 1992. Over 50% of our current urban forestry specialists (arborists) have been trained under this timing system. A detailed account of the evolution of our system of tree climbing training and productivity assessment will be presented and should be applicable to other urban forestry programs around the world.
CULTURAL BACKGROUND AND LANDSCAPE
HISTORY AS FACTORS AFFECTING PERCEPTIONS OF THE URBAN FOREST
by Evan D.G. Fraser and W. Andrew Kenney
Abstract. Because a large proportion of the urban forest grows on private property, it is necessary to have broad community support for urban forestry. As people from all over the world live in Canadian cities, it was hypothesized that people with different cultural backgrounds would have different perceptions of the urban forest. This hypothesis was tested by (1) researching different landscaping traditions; (2) interviewing members of four different communities; and (3) conducting vegetation inventories. Inventory and interview data provided a consistent picture of the four communities. The British community reacted the most positively to shade trees. They also expressed the greatest willingness to plant shade trees, had the most shade trees per square meter on their properties, and were the only group that liked naturalized parks (hiking paths). The Chinese community showed less yard maintenance than the other communities, and many of the Chinese indicated that they did not want to add trees to their property. The Chinese responded more favorably than the other groups to photographs depicting landscapes free of trees. Italian and Portuguese communities emphasized fruit trees and vegetable gardens, and responded negatively toward shade trees when these were in conflict with their gardens. These cultural differences are largely consistent with the traditional use of trees in British, Mediterranean and Chinese landscaping, and appear to be maintained among North American immigrant populations.
IOWA COMMUNITIES BENEFIT FROM AN
EXTERNALLY FUNDED TREE-PLANTING PROGRAM
by Mark A. Vitosh and Janette R. Thompson
Abstract. In 1990, investor-owned utilities in Iowa began distributing funding dedicated to tree planting to communities through the nonprofit, volunteer-coordinating organization Trees Forever. To assess the impact of this tree-planting program, a questionnaire was mailed to 268 Trees Forever volunteers in communities throughout Iowa in 1996. The objectives of this study were to measure increases in community forestry activities in towns that received tree-planting funds through the organization Trees Forever and to gather opinions about project administration through funding agencies external to the community. The response rate for the survey was 63%. Four-fifths of the communities responding to questions about community forestry activities showed an increase in some forestry-related activities (e.g., volunteer tree-planting group, tree board, fund-raising activities, tree inventory) after they received external tree-planting funds through Trees Forever; two-fifths of them added as many as four new activities. Also, four-fifths of the survey respondents agreed that their community tree-planting program would not have started without external funding, in this case from utility companies. Our results suggest that the benefits of tree-planting programs are enhanced by assistance provided to communities by a funding agency or a volunteer-coordinating organization.
EFFECTS OF HORTICULTURAL OIL
AND FOLIAR- OR SOIL-APPLIED SYSTEMIC INSECTICIDES ON EUONYMUS SCALE IN
PACHYSANDRA
by Clifford S. Sador and D. Casey Sclar
Abstract. The relative abilities of horticultural oil, acephate, and
imidacloprid to control euonymus scale (Unaspis euonymi) throughout
the canopy of Japanese pachysandra (Pachysandra terminalis) were
compared. Distribution of scales and the level of parasitism were also
determined. Horticultural oil gave the greatest level of control (99%)
when applied in the dormant season followed by an application that targeted
mobile stages of the insects during the summer. Summer applications of
acephate gave good control (66%), while imidacloprid was not effective.
Most of the live and parasitized scales were observed in the middle and
basal portions of the plant canopy. Rates of parasitized scales never exceeded
25% in the control plots. Rates of parasitism were too low to distinguish
differences among rates of parasitism in the 4 treatments.