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Abstract
Photographs of five fully foliaged shade tree canopies (Acer. rubrum, Gleditsia triacanthos inermis, Gymnocladus dioicus, Pyrus calleryana, and Zelkova serrata) were taken using four film types, 50- and 28-mm lenses, and a range of three f-stops. Photographs of four leafless shade tree canopies (Gleditsia, Gymnocladus, Pyrus, and Zelkova) were taken using three film types and two lenses, at two f-stops. Film densities were determined with a light source and quantum sensor system for negatives of fully foliaged and leafless canopies and correlated with mean percentage of shade measured with a pyranometer. Pan-X film, at the correct f-stop setting, gave the highest correlation to mean percentage of the fully foliaged canopies. The 50-mm lens gave a higher correlation than the 28-mm lenses. Plus-X film, at an f-stop one above the proper setting, gave the highest correlation to mean percentage of shade of the leafless canopy. Plus-X film produced the most consistent results when photographs of the leafless canopy were taken during different days and times of the day. Using a densitometer to measure film density of the negatives gave high correlations to mean percentage of shade of the leafless canopy.
Abstract
Five species of ornamental trees were examined with an Eppley pyranometer for interception of total solar radiation between 380 nm and 1100 nm. Measurements were made at the northern dripline and expressed as percentage of shade. Trees were selected for varying forms, branch, and canopy densities. Mean percentage of shade for the fully foliaged and leafless canopies, respectively, were Pyrus calleryana ‘Chanticleer’ 75% and 43%, Acer rubrum ‘Red Sunset’ 69% and 25%, Zelkova serrata ‘Village Green’ 61% and 24%, Gymnocladus dioicus 60% and 15%, Gleditsia triacanthos inermis ‘Moraine’ 56% and 21%. No statistically significant (PSO.05) correlation was observed among solar radiation intercepted and photosynthetically active radiation (PAR) intercepted, pathlength, silhouette area, and canopy volume. Growth habit did not affect shading capacities significantly.
Extension Master Gardener (EMG) volunteers are key to effective dissemination of horticultural information to the public. The goal of this workshop was to identify techniques to increase the capacity and effectiveness of EMG volunteers. The workshop focused on projects and tools that reduce the administrative burden of managing volunteers, increase the scope of issues that volunteers are prepared to address, and pool volunteer efforts and resources across county lines. Two online systems for managing and reporting EMG volunteer activities were described. Both systems are intuitive, user-friendly, and updated without the assistance of web managers. Regional web-based, advanced training on specific topics was used to expand educational messages of EMG volunteers and eliminate the costs associated with face-to-face training. Presentations were made using distance learning technologies and resources were shared online. Hosting agents tailored hands-on supporting activities to meet local needs. Volunteers expanded extension outreach by answering noncommercial landscape and garden telephone questions. Many of the administrative, logistical, and resource burdens associated with the EMG helpline phone service were overcome by working across county lines, standardizing training, centralizing supporting resources, and clustering volunteers into regional telephone helpline offices. Other projects and tools presented in the workshop focused on the need to affirm and/or foster the volunteers' connection with the university and the outreach mission of Cooperative Extension.