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EXPENDITURES ASSOCIATED
WITH CONFLICTS BETWEEN STREET TREE ROOT GROWTH AND HARDSCAPE IN CALIFORNIA,
UNITED STATES
by E. Gregory McPherson
Abstract. A survey of 18 California cities indicated that approximately $70.7 million (se $11.1 million) was spent annually statewide due to conflicts between street tree root growth and sidewalks, curbs and gutters, and street pavement. The largest single expenditure was for sidewalk repair ($23 million, se $9.5 million), followed by curb and gutter repair ($11.8 million, se $2.6 million), and trip and fall payments and legal staff time ($10.1 million, se $2.2 million). Property owners paid 39% and 17% of tree-related sidewalk and curb and gutter repair costs, respectively. Substantial funds were invested to remove and replace trees in conflict with hardscape ($6.8 million, se $3.6 million), and for inspection and repair administration programs ($5.9 million, se $1.3 million). Root pruning ($2.5 million, se $2.0 million) and root barriers ($676,854, se $175,655) were the most important mitigation and prevention measures. Restricted planting space and the type of tree species selected were reported as the most important factors responsible for hardscape damage.
TRANSPLANTING SUCCESS OF
BALLED-AND-BURLAPPED VERSUS BARE-ROOT TREES IN THE URBAN LANDSCAPE
by Michelle J. Buckstrup and Nina L. Bassuk
Abstract. In this study, 40-mm-caliper (1.5-in.) balled-and-burlapped
(B&B) and bare-root (BR) hackberry (Celtis occidentalis), American
hophornbeam (Ostrya virginiana), and swamp white oak (Quercus
bicolor) were paired and planted on sites throughout the city of Ithaca,
New York. Half of the trees were planted in fall, half in spring. BR trees
received a hydrogel root dip at the nursery to prevent post-harvest root
desiccation. Survival rates were excellent for all treatment combinations
except spring-planted BR hophornbeam, which experienced 50% mortality.
Growth measurements were taken in August of the first and second growing
seasons. First-year results showed many significant differences between
treatments. By the end of the second growing season, however, very few
significant differences in growth responses between treatments persisted.
During the first growing season, fall-planted BR hackberry grew better
than fall-planted B&B hackberry. Growth on spring-planted hackberry
was better on B&B trees. Fall-planted hop-hornbeam responded equally
well B&B and BR, but spring-planted hophornbeam grew better B&B.
Swamp white oak grew somewhat better B&B than BR, regardless of season.
Both B&B and BR swamp white oak planted in fall grew somewhat better
than their spring-planted counterparts. A separate study on swamp white
oak looked at the impact of withholding irrigation on spring-planted, paired
B&B and BR trees. B&B and BR swamp white oak trees performed equally
well after two growing seasons characterized by drought.
REPLACEMENT OF TREES UNDER
UTILITY WIRES IMPACTS ATTITUDES AND COMMUNITY TREE PROGRAMS
by Dana E. Flowers and Henry D. Gerhold
Abstract. Opinions of people in 54 Pennsylvania municipalities
who received trees through the Municipal Tree Restoration Program (MTRP)
were surveyed, and progress in their tree programs also was evaluated.
All municipal tree program components, such as ordinances, tree commissions,
inventories, and management plans, were stimulated by the MTRP to varying
extents in one or more ways in 91% of the municipalities. Responses from
residents showed high approval for removal of large trees that interfered
with utility wires, though some did miss them, and for replacement with
smaller-growing cultivars of Amelanchier, Crataegus, Malus, Pyrus,
and Syringa. Responses across all genera indicated that 82% liked
the planted trees, 77% thought they improved the neighborhood, and 69%
favored removal of the large trees when they were replaced by smaller trees.
Only 8% greatly regretted the removals and 3% offered negative comments
about the removal of large trees or replacement with smaller species. Comments
about likes and dislikes were mainly about tree characteristics and varied
among genera. The most common complaints were about messy fruit, and the
best-liked qualities were flowers and other aesthetic traits. There was
little variation in attitudes among communities, three of which differed
from the others in their opinions about Malus cultivars, which seemed
to relate mainly to the nature of the trees and their fruit.
ASSESSING RESIDENTS’ WILLINGNESS
TO PAY TO PRESERVE THE COMMUNITY URBAN FOREST: A SMALL-CITY CASE STUDY
by Alfredo B. Lorenzo, Catalino A. Blanche, Yadong Qi, and Malcolm
M. Guidry
Abstract. Residents’ willingness to pay for community urban forest
preservation was assessed using a survey questionnaire mailed to 3,009
households in the city of Mandeville, a suburb of New Orleans, Louisiana.
Survey responses indicated the following: 1) residents’ willingness to
pay for urban forest protection and preservation is positively associated
with their perceptions of the benefits of trees but negatively associated
with their perceptions of the annoying features of trees; 2) the willingness
to pay a higher premium (>$12) for tree preservation and protection is
directly related to income levels; 3) more female than male respondents
are willing to pay $6 to $12 per year for tree preservation but more male
than female respondents are willing to pay more than $12 per year for tree
preservation; 4) age, level of education, and type of residential ownership
are not significantly associated with willingness to pay for tree preservation
and protection; 5) more than 80% of respondents view the protection and
preservation of urban trees as very important functions of the city and
are willing to pay additional taxes for tree protection and preservation;
and 6) more than 88% of respondents rate the city’s overall performance
in tree protection and maintenance as good to excellent. The survey results
may find utility in crafting more effective support programs for urban
tree protection and preservation.
PATHOGENICITY OF CYTOSPORA
FUNGI ON SIX HARDWOOD SPECIES
by J.B. Kepley and W.R. Jacobi
Abstract. Cytospora canker is a serious fungal disease of many
shade, fruit, and ornamental tree species in the urban forest, orchards,
and nurseries. Because Cytospora species are difficult to identify
and their host ranges are poorly understood, it is not known if disease
occurrence on one host poses a threat to other host species. Cytospora
isolates were collected from aspen (Populus tremuloides) (Cytospora
chrysosperma), green ash (Fraxinus pennsylvanica) (Cytospora pruinosa),
Siberian elm (Ulmus pumila) (Cytospora sacculus), alder (Alnus
spp.) (Cytospora umbrina), cottonwood (Populus spp.) (Cytospora
chrysosperma), and multi- and single-stemmed willow (Salix spp.)
(Cytospora fugax). These isolates were inoculated into drought-stressed
aspen, green ash, Siberian elm, thinleaf alder (A. tenuifolia),
eastern cottonwood (P. deltoides), and single-stemmed willow. Ash,
alder, and elm isolates were host specific. Aspen and cottonwood isolates
were pathogenic only on aspen and cottonwood trees. Isolates from multi-stemmed
willows caused cankers on aspen only and not single-stemmed willows. However,
Cytospora spp. isolates collected from a single-stemmed willow were
pathogenic on trees cloned from that willow. Water potential, as a covariate,
did not explain variation in canker size among trees. Thus, Cytospora
fungi that are host specific may not be a threat to other nearby tree species.