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GIS ASSESSMENT OF MUNICH'S URBAN
FOREST STRUCTURE FOR URBAN PLANNING
byStephen Pauleit And Friedrich Duhme
Abstract. A geographic information system (GIS) was developed and applied to assess the spatial pattern and environmental functions of the urban forest in the city of Munich. Urban land cover types were delineated as the underlying spatial units, characterized by physical and land-use attributes such as the percentage cover of built-on land and vegetation. The urban forest was described as the cover of trees and shrubs and the maximum age of trees. The survey was coupled with statistical databases and environmental data such as a habitat survey and thermal infrared photography. Trees and shrubs covered approximately 5,400 ha (13,300 ac) of land, or 18% of Munich's surface area. The spatial pattern of the urban forest was closely linked with the general zoning of different land use and building density. The relationship between cover, size, and age of woody vegetation and the incidence of woodland indicator birds was used to assess the role of the urban forest for urban nature conservation, and potential habitat links of closely neighboring woodlands were identified by means of the GIS. Furthermore, it was shown that the urban forest can effectively reduce air temperatures during hot summer days. Specific urban forestry programs and quantitative targets were proposed for urban zones. These would increase the forest cover to 22% of the city's surface area. An estimate for the overall costs for the establishment of the additional forest areas is given.
SPECIFICATION OF SOIL VOLUME
AND IRRIGATION FREQUENCY FOR URBAN TREE CONTAINERS USING CLIMATE DATA
by Arthur T. DeGaetano
Abstract. Typically, limitations in soil volume deprive urban trees of water supplies adequate to meet evapo- transpirational demand, resulting in suboptimal tree survival, health, and development. Proper sizing of urban tree containers can mitigate these unfavorable consequences. Current recommendations of appropriate soil volumes for urban trees are based on average climate conditions and therefore do not address daily and annual variations in weather. The method developed in this paper uses daily climatological data to estimate the soil volume necessary to provide some minimal amount of moisture during the driest growing season likely to be encountered during an urban tree's expected lifespan. This method allows a range of historic weather conditions to be taken into account. For example, in New York City, without irrigation a medium-sized tree (6-m [20-ft] crown diameter) grown in 17 m3 (600 ft3) of soil would face a water deficit (<50% available water capacity) every other year. When provided with 27.4 m3 (967 ft3) of soil, this tree would face a deficit only once in 10 years. If only 4.3 m3 (152 ft3) of soil volume can be supplied, such a tree, when irrigated approximately once every 5 days, would face a water deficit (<70% available water capacity) once in 10 years.
URBAN FORESTRY RESEARCH IN EUROPE:
AN OVERVIEW
by Cecil C. Konijnendijk, Thomas B. Randrup, and Kjell Nilsson
Abstract. A comprehensive European overview of recent and ongoing research in Europe was carried out within the framework of COST Action E12, "Urban Forests and Trees," a pan-European research network. This paper presents some of the main findings of a comparative analysis of 20 individual country reports. The analysis shows that research on urban forests and urban trees in Europe has a wide scope and is rather fragmented and uncoordinated. Universities and state research institutes, mostly with a forestry or horticultural background, dominate the research. Relevant research is primarily funded from state and municipal sources. Significant differences exist between countries with regard to the level of activity, research topics and institutions involved.
SURVIVAL AND GROWTH OF TRANSPLANTED
LARGE- AND SMALL-CALIPER RED OAKS
byDaniel K. Struve, Laura Burchfield, and Cathy Maupin
Abstract. Red oak (Quercus rubraL.) of 2 caliper sizes, 8.4 and 3.6 cm (3.3 and 1.4 in.), and 2 vigor classes (high and low) within the small-caliper trees, were transplanted to compare growth and establishment over a 4-year period. Possible confounding factors such as pre-transplant vigor, genetics, relative root-ball to backfill volume, and relative canopy to root-ball volume were controlled to determine whether small-caliper trees establish more rapidly than large-caliper trees. Large-caliper trees had high mortality, 58%, while no small-caliper trees died. Based on trunk caliper and height growth after transplanting, surviving large-caliper trees established faster than small-caliper treesÑdemonstrating that transplanted large-caliper red oaks can establish as rapidly as small-caliper red oaks.
BRACE RODS FOR CODOMINANT STEMS:
INSTALLATION LOCATION AND BREAKING STRENGTH
by E. Thomas Smiley, Craig M. Greco, and James G. Williams
Abstract. The location at which brace rods should be installed to reduce the risk of breakage in codominant stems traditionally has been below the crotch. In this study, codominant stems were pulled apart with measured force to determine if crotch strength was increased by installing a rod above the crotch rather than in the traditional rod location below the junction. With both red oak (Quercus rubra) and red maple (Acer rubrum), the strength of the codominant stem was increased significantly by installing the rod above the crotch a distance equal to the diameter of one of the stems. Brass rods tended to fail more than steel rods in oak but may be useful in small, weaker-wooded trees.
FERTILIZER RATE AND TYPE IMPACTS
MAGNOLIA AND OAK GROWTH IN SANDY LANDSCAPE SOIL
by Edward F. Gilman, Thomas H. Yeager, and Donald Kent
Abstract. Southern magnolia (Magnolia grandiflora) planted as
3-L (1-gal) liners into sandy soil did not respond to nitrogen applications
above 20 g N/m2 (4.2 lb N/1,000 ft2) per year the
first 2 years after planting. The 40 g N/m2 (8.3 lb N/1,000
ft2) per year rate resulted in greater height than the 20-g
(4.2-lb) rate in the third year and greater height and trunk diameter the
fourth year after planting. Nitrogen rates greater than 40 g N/m? did not
result in more growth. Seedling magnolia and 10- to 13-cm (4- to 5-in.)
caliper field-grown live oak (Quercus virginiana) trees receiving
nitrogen soon after transplanting responded the first year of application
by growing faster than those that received no nitrogen. Nitrogen source
had little impact on growth or tissue nitrogen concentration (1.4%) of
10- to 13-cm-caliper live oak in the first 3 years after field transplanting,
and there was no N source effect on root extension from the trunk. All
fertilizers containing nitrogen promoted growth. Nitrogen applications
increased trunk growth on 23-cm (9-in.) caliper live oak beginning about
16 months after transplanting with a tree spade. Potassium and/or phosphorus,
when applied in conjunction with nitrogen, had no effect on growth.