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Valuation of Tree Aesthetics
on Small Urban-Interface Properties
by Richard Thompson, Richard Hanna, Jay Noel , and Douglas Piirto
Abstract. A model was developed to predict the value contribution of forest condition on small urban-wildland interface properties. Sample data were collected on property transactions in the Lake Tahoe Basin of California between 1990 and 1994. A variant of the stand density index (SDI) and a tree health measure were added to a list of traditional property characteristics (i.e., location, house size, lot size) to express the influence of tree care on property value. These aesthetic characteristics were statistically significant despite the expected dominant influence of the traditional characteristics. Values for the forest density and health characteristics were estimated and reveal a contribution to property value between 5% and 20%.
Benefit-Cost Analysis of Modesto’s
Municipal Urban Forest
by E. Gregory McPherson, James R. Simpson, Paula J. Peper , and
Qingfu Xiao
Abstract. This study answers the question: Do the accrued benefits from Modesto’s urban forest justify an annual municipal budget that exceeds $2 million? Results indicate that the benefits residents obtain from Modesto’s 91,179 public trees exceeded management costs by a factor of nearly 2. In fiscal year 1997?1998, Modesto spent $2.6 million for urban forestry ($14.36/resident, $28.77/tree), and 74% of this amount was for mature tree care. Total annual benefits from Modesto’s urban forest were $4.95 million ($27.12/ resident, $54.33/tree). Net benefits for FY 1997?1998 were $2,329,900 ($12.76/resident, $25.55/tree). Annual air-pollutant uptake was 154 metric tonnes (3.7 lb/tree), with an implied value of $1.48 million ($16/tree). Aesthetics and other benefits had an estimated value of $1.5 million ($17/tree). Building shade and cooler summer temperatures attributed to street and park trees saved 110,133 MBtu, valued at $870,000 (122 kWh/tree, $10/tree). Smaller benefits resulted from reductions in stormwater runoff (292,000 m3 or 845 gal/tree, $616,000 or $7/tree) and atmospheric carbon dioxide (13,900 t or 336 lb/tree, $460,000 or $5/tree). Due to the population’s relatively even-aged structure and heavy reliance on mature Modesto ash for benefits, management strategies are needed that may reduce net benefits but increase diversity and stability.
Greenhouse and Field Growth
of Northern Red Oak Seedlings Inside Different Types of Treeshelters
by William E. Sharpe, Bryan R. Swistock, Kelly A. Mecum, and Michael
C. Demchik
Abstract. Greenhouse and field experiments were used to measure growth and survival of northern red oak seedlings (Quercus rubra L.) inside brown translucent, clear acrylic, and woven wire treeshelters compared to the growth and survival of unsheltered seedlings. In the greenhouse, seedlings grown in brown plastic and clear acrylic shelters had significantly reduced stem, leaf, and root development compared to unsheltered seedlings. Seedlings in clear shelters grew taller than control seedlings, but none were self-supporting after removal of the shelters. Reduced growth in the brown shelters was attributed to an 80% reduction in photosynthetically active radiation (PAR). In the field study, 2-year-old red oak seedlings grown in brown and clear shelters experienced lower mortality (55% and 40%, respectively) than unsheltered seedlings (60%), but most were unable to support themselves after removal of the shelters because of increased height growth and inadequate stem development. Half of the seedlings inside clear shelters experienced dieback of new growth during an unusually warm early growing season. Seedlings in the wire shelters were not supported or protected from mechanical stress (wind) and they were exposed to ambient temperatures. Wire-shelter seedlings had the lowest mortality (20%) and were self-supporting but significantly shorter than seedlings in the clear and brown shelters. Wire shelters show promise as an alternative to solid plastic shelters for producing self-supporting seedlings with comparable growth and greater survival at a similar overall cost.
Identification of Alternative Hosts
of Xylella fastidiosa in the Washington, D.C., Area Using Nested Polymerase
Chain Reaction (Pcr)
by Andrew J. McElrone, James L. Sherald, and Margaret R. Pooler
Abstract. A survey of 27 herbaceous and woody plant taxa was conducted to identify possible alternative hosts of the xylem-limited bacterium, Xylella fastidiosa. Samples were collected from wild and cultivated plants inhabiting and surrounding the National Park Service Daingerfield Island Nursery in Alexandria, Virginia, and from national parks in Washington, D.C. These samples were analyzed using up to 3 different bacterial extraction methods and a 2-step, nested polymerase chain reaction (PCR) amplification using oligonucleotide primers specific to X. fastidiosa. Six out of the 27 sampled plant taxa tested positive. Acer negundo, Aesculus ¥ hybrid, Celastrus orbiculata, Cornus florida, and Hedera helix have not been previously confirmed as hosts, while Vitis species have been described as wild and cultivated hosts in numerous studies. Eleven of the 27 taxa could not be tested due to failure to amplify X. fastidiosa DNA in the positive controls, regardless of the extraction method.
Using Ecosystem-Based and Traditional
Land-Use Planning to Conserve Greenspace
by W.F. Elmendorf and A.E. Luloff
Abstract. When conserved in greenspace, natural systems—forests, stream corridors, and chaparral—provide many benefits to people and communities. Conserving greenspace, then, requires traditional land-use planning and regulation, which provides local governments powerful tools and processes. Greenspace conservation can be hampered by a lack of intermunicipal cooperation, disregard for natural systems within the planning process, and concerns for the taking of private property rights. Because of a broad-scale approach, an ecosystem-based approach to community forestry can support traditional land-use planning in conservation efforts across the many landscapes and through the people involved in community development. Use of an ecosystem approach has problems, however, including the building of cooperation and partnership between multiple jurisdictions and agencies. Furthermore, a lack of awareness and involvement by community foresters and arborists may impede the success of either traditional or ecosystem planning approaches in conserving greenspace.
Effects of Pruning in the Management
of Dogwood and Pine Branch Dieback in the Landscape
by Gary W. Moorman and Roxanne J. Lease
Abstract. Scots pines (Pinus sylvestris L.) at 2 locations and dogwoods
(Cornus florida L.) at 1 location were observed for branch dieback from
spring 1996 through autumn 1998. Some trees at each location were comprehensively
pruned to eliminate dead twigs and branches and compared to trees not pruned.
Of the branch-killing fungi present, Sphaeropsis was the most important
in the pines, and Discula and Botryosphaeria were the prominent ones in
the dogwoods. We concluded that comprehensive pruning of branches killed
by fungi significantly improves the appearance of Scots pines and dogwoods
but does not totally eliminate disease from the trees.