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Using High-Technology Instruments
to Assess Defects in Trees
by Giovanni Nicolotti and Paolo Miglietta
Abstract. The technical features of instruments used to assess
wood defects are described and opinions are expressed on their reliability,
ease of use, and interpretation. The instruments include penetrometers,
electrical conductivity meters, sonic and ultrasonic detectors, thermography,
radar, and X-ray tomography.
Mass Trapping for Japanese Beetle
(Coleoptera: Scarabaeidae) Suppression in Isolated Areas
by by Robert P. Wawrzynski and Mark E. Ascerno
Abstract. Mass trapping to reduce an isolated population of Japanese
beetles (Popillia japonica) was investigated. Four years of mass
trapping produced a 97% reduction in P. japonica numbers. Although
this study lacked strict statistical controls, we feel it shows mass trapping
for isolated Japanese beetle populations has merit. Therefore, under certain
conditions mass trapping, as part of an integrated pest management program,
may be useful for reducing P. japonica populations.
Mycorrhizae of Landscape Trees
Produced in Raised Beds and Containers
by David Sylvia, Abid Alagely, Donald Kent, and Roy Mecklenburg
Abstract. Mycorrhizal associations provide a linkage between
tree roots and the soil, thereby contributing to the tolerance of trees
to environmental stresses. Little, however, is known about the mycorrhizal
status or dependency of many landscape trees. The objective of this study
was to quantify mycorrhizal root colonization and spore formation on a
diverse collection of ornamental tree species grown in raised beds or containers
at an established tree farm in central Florida. In addition, root diameters
were measured to determine if there was a relationship between this parameter
and mycorrhizal formation. A total of 23 tree species were sampled; 9 were
present both in containers and raised beds, 6 species were present in containers
only, and 8 species were present as embedded plants only. The proportion
of root length colonized by mycorrhizal fungi ranged from 0% to 83%. Mean
arbuscular mycorrhizal spore numbers ranged from <20 to nearly 500 spores
100 g1 (3.5 oz1). Mean root diameters ranged from < 500 to
> 1,000 m (0.0197 to 0.0394 in.). No relationship was found between root
coarseness and mycorrhizal root colonization or sporulation. The majority
of trees formed mycorrhizae of the arbuscular type. Five species in the
family Pinaceae or Fagaceae had the potential to form ectomycorrhizae;
however, they were poorly colonized. Future research should be directed
toward understanding the importance of mycorrhizae to landscape trees,
including effects on tree survival and growth and the effect of fertilizer
and pesticide applications on mycorrhizal development.
Inclusive Urban and Community
Forestry Programs: Using All of Your Community's Cultural Resources
by Jeffery K. Iles
Abstract. The thoroughly documented benefits from healthy, properly
managed tree populations and less intensively managed greenbelts are not
immediately apparent to all members of a community. Most citizen volunteers,
local professional arborists and horticulturists, and the occasional politician
that involve themselves in planting and maintaining their community's tree
resource have at least a cursory understanding of the social, psychological,
economic, and environmental benefits provided by trees. Yet many other
segments of the population have had little to do with urban and community
forestry issues. Enlisting the support of nontraditional audiences can
only enhance urban and community forestry programs and strengthen the argument
for increased funding needed to sustain this valuable resource.
An Unusual Attack Pattern of Scolytus
Multistriatus Beetles in Chinese Elm
by Pavel Svihra
Abstract. In autumn, some Chinese elm (Ulmus parvifolia Marsham)
trees, especially those with large seed crops, attract Scolytus multistriatus
beetles. The beetles land on a single tree in masses and attempt to penetrate
the inner bark. The tree responds with a copious flow of sticky sap that
kills beetles at entrances or repels them. As the sap flow increases, Scolytus
beetles aggregate on the tree in even larger numbers and continue to excavate
very short, erratic, and shallow tunnels in the outer bark. The basal to
mid-bole section was attacked with highest density (17 to 18 tunnels per
dm2, with a male-to-female ratio of 1:8.7). Perhaps due to a high concentration
of host volatiles and insect-produced attractants, S. multistriatus beetles
shifted their attack to adjacent elms. However, the beetles avoided penetrating
the inner bark of these trees and excavated only shallow tunnels in the
outer bark. The beetles also showed a preference for tunneling into the
basal to mid-bole section, but high mortality was observed (36.3% to 40.7%,
with a male-to-female ratio ranging from 1:3.8 to 1:4.3). The number of
female beetles and number of feeding scars in the crotches of small twigs
were dependent on the number of females in the stem and branches (P 0.001).
Evaluation of the Planning, Implementing,
and Monitoring of the Urban Forest in Recife, Pernambuco, Brazil
by Isabelle Maria Jacqueline Meunier, José Antônio Aleixo
da Silva, and Crueza Maria dos Santos
Abstract. Techniques for planning, implementing, and monitoring
urban forest management in the Municipal Department of Recife, Brazil,
were analyzed. During two months in 1996, planting and pruning programs
were also evaluated. We observed an absence of planning and a failure to
employ technical approaches in species selection, installation, and pruning.
We identified such problems as planting trees of medium size under power
lines, use of saplings of poor form, insufficient space for the growth
of the trees, lack of fertilization and other cultural treatments, inadequate
pruning, and inefficient systems for follow-up monitoring and evaluation.
An urban forest management plan was recommended to the city.
Phytophthora Decline of Alder
(Alnus spp.) in Europe
by Thomas L. Cech
Abstract. In several European countries, alder (Alnus glutinosa and A. incana) growing along rivers is threatened by a decline that is consistently related to stem necrosis caused by Phytophthora. It was first thought to be a form of Phytophthora cambivora, but morphological differences as well as its homothallism indicate a new species. High pathogenicity on A. glutinosa and A. incana have been proven by experiments in Great Britain, the Netherlands, and Germany. At present the disease is widespread in Great Britain, whereas in Denmark, France, Germany, Ireland, the Netherlands, and Sweden only a few cases have been reported. In Austria, decline of A. glutinosa was observed in 1986 and 1996. Symptoms include simultaneous crown decline, preceded by abnormally small leaves, stem necrosis, and exudates from the bark resulting in tarry spots. Cracks at the stem base with strong callus formation suggest earlier attacks or mechanical injuries prior to infection. Several times Phytophthora was isolated, and it showed high similarity to British strains. In addition, other bark-attacking fungi were identified, among them Phomopsis alnea, Ophiovalsa suffusa, Pleomassaria holoschista, and Pezicula cinnamomea. Probable predispositions, such as drought periods followed by heavy rainfall, and severe winter frost are discussed along with practical control measures, such as fungicide treatment.