Abstract BackgroundTree risk assessment methods have been developed to assist arborists in conducting thorough and systematic inspections of trees and the threat they pose to people or property. While these methods have many similarities, they also have a few key differences which may impact the decisions of those employing them. Moreover, arborists specify the associated timeframe for their risk assessment, which can range from months to years. How this impacts risk assessment reproducibility is unknown.MethodsTo assess the impact of risk assessment methodology, we sent videos depicting trees in urban settings to arborists holding the International Society of Arboriculture (ISA) Tree Risk Assessment Qualification (TRAQ;n= 28) or Quantified Tree Risk Assessment (QTRA;n= 21) training. These assessments were compared to those prepared by North American arborists lacking the TRAQ credential (ISA BMP;n= 11). ISA BMP arborists were also asked to assess trees using both a 1-year and a 3-year timeframe.ResultsWhile a direct comparison between the QTRA and TRAQ assessments is not possible given differences in terminology, arborists with the latter training were less likely to rate trees as having “high” or “extreme” risk compared to their ISA BMP counterparts. Moreover, we found that switching to a longer timeframe did not increase the variability of risk assessments.ConclusionsThese results give further insights into how different risk assessment methods compare when assessing the same group of trees as well as the impact of training efforts and specified timeframe.

An aggregate of 82 American elms in Syracuse New York and Washington D.C. naturally infected with Dutch elm disease were given therapy by pruning infected limbs, injection of benzimizol fungicides, or combinations of these treatments. Pruning alone was applied only when there was a distance of 3 m or more from the last visible streak to the distal cut. Pruning without injection was successful in each of 10 current year infections, but in none of 3 residual infections. Fungicide injection without pruning succeeded in 76% of current year and 33% of residual infections. Fungicide injection plus pruning was successful therapy for 100% of the current year and 71% of the residual infections. Each of five "incurable" trees showed no further symptoms after fungicide was injected directly into infected wood in a large limb or the bole as well as into the root collars. Relatively massive injection of fungicide in trees with root graft-transmitted DED did not succeed.

Holmes: Towns With Tree Names 3. Many named communities may have no separate postal code number or no separate town government, yet they appear on maps and bear tree names.

An equipment system was developed for injection of a low vol of coned aqueous growth regulator solution into shade trees for sprout-regrowth control. The injection equipment is air powered and injects a precise vol into each injection site. Vol and pressure can be easily adjusted. The injectors are small diam and, therefore, easily force fitted into drilled holes and easily removed by hand. Tree disfigurement is not significant. The system has been field tested on several tree species and is at a commercial-prototype stage. Its design is described in detail.

In 1975, the Urban Forestry Committee of the International Society of Arboriculture made a survey that revealed ar­boriculturally oriented courses were offered in at least 52 North American University Horticultural Schools. Titles of these courses as well as related curricula are listed. Com­ments are also given on arboricultural education in general. It is the author's opinion that current and planned arboricultural educational opportunities are more than adequate to meet the educational and training needs of commercial, municipal, and utility arboricultural management organizations. Research and development activities, however, should be strengthened to support educational and management programmes.