Nationally, the urban and community forests are in a state of rapid decline. About 52% of street trees are dead or dying. The average tree life of the urban areas is about five times less than in rural areas. The growing national awareness of the importance and benefits of trees and their role in maintaining a healthy environment magnifies the need for urban forestry training programs. The Southern University Urban Forestry Program (funded by USDA Forest Service, Southern Region) is set up to address the critical need for high quality, user-oriented urban forestry training for minority students, and to bridge the gap between minority participation and national forestry resources, education and management programs. This unique program places major emphasis on experiential learning activities in addition to sound academic education. The four-year curriculum will be centered around forestry, horticulture, urban and community planning and landscape architecture.
Flowering dogwood is an important tree of forests and urban landscapes in the eastern United States. This native tree blooms early in the spring as new leaves unfold. The inflorescence consists of petallike subtending bracts of red, pink, or white
Throughout the world the nature of man has been to cluster in highly urbanized centers. The U.S. is no exception, with more than 203 million people living on less than 1% of the land mass. During the past decade this concentration of people in or near urban growth centers has continued while an increasing percentage of land area in many states has reverted to forest cover.
Studies have shown that many people prefer landscapes with vegetation over those devoid of plants. Few studies have looked specifically at adolescents or people of different ethnic heritages. Understanding preferences of such groups could help in designing horticultural education programs for these populations. In this study, high school students were asked to rate their preferences for a series of plant-dominated and urban-dominated slides.
Students generally gave higher ratings to the plant scenes than the urban scenes, indicating that they preferred the plant scenes. Their preferences were similar to what would be predicted from studies with adults. Hispanic students rated urban scenes and formal plant scenes, such as a garden with sculptured shrubs, significantly higher than did Anglo students. Hispanics rated informal scenes, such as a deciduous forest with no ground cover, significantly lower than did Anglo students.
This research protocol was approved by the WSU Human Subjects Institutional Review Board. Financial support was provided in part by the U.S. Department of Agriculture Forest Service Urban and Community Forestry Program on the recommendation of the
More than 70 biogenic hydrocarbon (BHC) compounds are known to be emitted by plants, but only a few are emitted in relatively large quantities. The magnitude of BHC emissions from individual trees is affected by ambient light and temperature, species-specific emissions rates, and leafmass. Like other volatile organic compounds (VOC), BHC emissions react with oxides of nitrogen (NOx) to form ozone and, thus, can contribute to urban air pollution. On average, BHC emissions are as reactive or more reactive than the VOC emissions from automobiles and can have higher ozone-forming potential. An accurate estimate of the overall magnitude of BHC contributions is important in formulating strategies to reduce peak ozone concentrations because an effective strategy will take into account the relative strengths of NOx and VOC emissions. The choice between NOx and VOC controls is crucial since an incorrect emphasis may result in non-attainment of ozone-reduction goals and control measures for either NOx or VOC involve enormous costs. As part of a program to develop a reliable BHC emission inventory for the Central Valley of California, a quantitative investigation of the leafmass of urban trees was conducted. Twenty-one trees in Bakersfield, Calif., were harvested and leaves removed, dried, and weighed. Leaf masses per tree ranged from 1.5 to 89.6 kg. Leaf mass densities (dry leaf mass per area of crown projection) ranged from 150 to 3200 g·m-2, as much as eight times greater than leaf mass densities for deciduous forests and more than twice those for coniferous forests. These data suggest the BHC contributions of urban trees may be underestimated if their foliar masses are calculated using forest-based leaf mass density data.
In a unique partnership. the University of Kentucky Dept. of Horticulture, the Cooperative Extension Service, and the Kentucky State Division of Forestry are teaming up to produce two training packages for “train-the-trainer” workshops throughout the state. The workshops will be open to people interested in urban/community trees and arboriculture.
The first training session will be held in 1993 and will cover five modules: 1) Designing the planting site to compensate for a disturbed environment; 2) Species selection for the existing site; 3) Scientific planting techniques; 4) Post-planting care: and 5) Integrated pest management.
The second training session will be held in 1994 and will cover the following topics: 1) Establishing a scientific management program for the urban forest; 2) Preparation and administration of grants: 3) Fund-raising and efficient use of volunteers; 4) Developing an urban tree inventory; 5) Recognition of hazard trees; and 6) Selecting quality nursery stock.
The training packages will consist of a written manual, videos, and slide sets. Training sessions are open to foresters, county agents, city planners, developers, and others in Kentucky who are interested in returning to their communities and training others on the topics covered.
1 Soil physicist. 2 Urban forest researcher. 3 Professor. The cost of publishing this paper was defrayed in part by the payment of page charges, Under postal regulations, this paper therefore must be hereby marked advertise ment solely to indicate
Urban sprawl of the greater Phoenix metropolitan area is rapidly replacing agricultural and non-irrigated desert vegetation with an irrigated urban forest comprised of a mixture of woody ornamental plant materials. Our objective was to estimate and compare the carbon acquisition potential (CAP) of residential landscape plants to the dominate plant species found in adjacent agricultural and desert sites. Maximum shoot and leaf gas exchange measurements were made at monthly intervals for one year (Aug. 1998 to July 1999) using a portable photo-synthesis system. Concurrent diel gas exchange measurements were made seasonally. Gas exchange measurements were made on alfalfa at agricultural sites, blue palo verde, creosote bush and bur sage at desert sites, and on a mixture of 19 different woody ornamental tree, shrub and ground cover species at residential sites. A trapezoidal integration model was used to estimate daily CAP at each site based on maximum assimilation flux values and seasonally adjusted diel assimilation patterns. Annual landscape CAP was then calculated as the summation of estimates of daily CAP. Calculated annual CAP was highest at agricultural sites (159.0 mol/m2 per year), lowest at desert sites (35.3 mol/m2 per year), and intermediate at residential landscape sites (99.3 mol/m2 per year).
As forests, agricultural fields, and suburban and urban lands are replaced with impervious surfaces resulting from development, the necessity to recover green space is becoming increasingly critical to maintain environmental quality. Vegetated or green roofs are one potential remedy for this problem. Establishing plant material on rooftops provides numerous ecological and economic benefits, including stormwater management, energy conservation, mitigation of the urban heat island effect, and increased longevity of roofing membranes, as well as providing a more aesthetically pleasing environment in which to work and live. Furthermore, the construction and maintenance of green roofs provide business opportunities for nurseries, landscape contractors, irrigation specialists, and other green industry members while addressing the issues of environmental stewardship. This paper is a review of current knowledge regarding the benefits of green roofs, plant selection and culture, and barriers to their acceptance in the United States. Because of building weight restrictions and costs, shallow-substrate extensive roofs are much more common than deeper intensive roofs. Therefore, the focus of this review is primarily on extensive green roofs.