ARBORICULTURE & CONTENTS URBAN FORESTRY Volume 48, No. 6, November 2022 Formerly the Journal of Arboriculture, 1975 – 2005 (Volumes 1 – 31) Brian Kane and Sanjay R. Arwade The Effect of Climbing Line and Ascent Technique on the Magnitude and Frequency of Arboricultural Climbing Loads .............................................................................................309 Abstract. Background: Arboricultural tree climbing is inherently dangerous, in part because of the possibility of failure of the tie-in point (TIP). To help climbing arborists choose TIPs wisely, we have conducted several studies to quantify the magnitude and frequency of loading associ- ated with arboricultural tree climbing. One parameter that has not been previously studied is whether the choice of climbing line influences loads experienced by a TIP as a climbing arborist ascends. Methods: The lead author conducted trials in which he ascended to 3 TIPs (in dif- ferent trees) using 2 ascent techniques and 3 different climbing lines. During each trial, we measured loads at the TIP, and from the resulting time histories analyzed the magnitude and frequency of loading. We compared the effect of ascent technique, climbing line, and their interac- tion on the magnitude and frequency of loading. Results: During trials, the magnitude of loading varied between 1.1 and 1.5 times the lead author’s weight and did not differ between ascent techniques, climbing lines, or their interaction. Loading frequency varied among ascent tech- niques, but not climbing lines. Footlocking induced loads at a wide range of frequencies, but 2 distinct frequencies were associated with rope- walking. Conclusion: Climbing arborists can use the results of this and our previous studies to help select a suitable TIP. It is important for climbing arborists to understand the magnitude of forces associated with ascending into and working in a tree. Future studies should investigate the load-bearing capacity of a TIP from the ground. Keywords. Loading; Safety; Tie-in Point; Tree Climbing. Alexander J.F. Martin Accuracy and Precision in Urban Forestry Tools for Estimating Total Tree Height .............319 Abstract. Background: Urban tree inventories are fundamental to the monitoring and management of urban forests. Various handheld tools and methods exist to conduct tree mensuration, ranging from the simple stick method to laser rangefinders. This study examines the accuracy and precision of the stick method, clinometer, and laser rangefinder, and introduces tree type (i.e., conifer versus broadleaf) comparisons of accu- racy and precision. Methods: Measurements were taken from 127 trees comprised of 85 (66.9%) broadleaf and 42 (33.1%) coniferous trees. Trees were distributed across 4 urban land use types: park, golf course, street, and trail system. A drone-mounted measurement tape was used to determine true height. Results: Measured heights ranged from 4.67 m to 25.71 m (x̄ = 13.19 m). Measurements from the stick method yielded statistically similar results to both the rangefinder and clinometer methods. The methods had a Cronbach’s Alpha of 0.991 (N = 3). Accuracy was highest for the rangefinder and lowest for the stick method. Precision was greatest between the rangefinder and the clinometer. Root-mean- square error (RMSE) and percent error were highest for the stick method and broadleaf trees for all 3 measurement methods. Conclusions: The findings indicate greater accuracy and precision across all tools when measuring conifers. The rangefinder was similar in accuracy to the cli- nometer, with notable changes in accuracy when using the stick method. Keywords. Forest Biometry; Forest Mensuration; Hypsometer; Tree Inventories; Urban Tree Measurements. Maggie L. McNulty and Lara A. Roman Forgotten Contributions: The Overlooked Impact of Ellen Harrison and Early 20th Century Women in Urban Greening ..........................................................................................333 Abstract. Many women and women-run associations were involved in historical urban beautification in the United States, especially tree plant- ing, in the late 19th and early 20th centuries. While men had formal roles as city foresters, arborists, horticulturalists, and landscape architects, women from elite families sometimes labored for free to organize and advocate for urban tree planting. Tightly knit social circles of high-society women in Philadelphia, Pennsylvania, yielded much greater influence in nascent tree planting and park creation movements than has generally been recognized. They often contributed their time, finances, input, and skill to landscape planting projects; however, they were not considered equal to the men who were compensated employees. These women planted, plotted, studied, and persevered, overcoming preconceived notions of womanhood, although their meaningful efforts were often viewed as merely an offshoot of their feminine domestic role. For women, limited ©2022 International Society of Arboriculture
November 2022
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