Roots of four-year-old, field-grown southern magnolia (Magnolia grandiflora L.) were pruned in 1987 once during dormancy, following the first shoot growth flush or after the second growth flush, prior to transplanting in January 1988. By the end of the 1987 growing season, root pruning at all stages of growth reduced leaf number, tree height, trunk caliper, and total-tree leaf area and weight compared with unpruned controls. Total root weight was less for trees pruned during dormancy or following the first growth flush. Root pruning increased the proportion of fine roots (0 to 5mm-diameter class) to coarse roots (>5 to 10-mm diameter class). Shoot:root ratios were not affected by root pruning. During the first year after transplanting, root pruned trees grew at a slightly faster rate than unpruned trees but growth rates were similar for root pruned and unpruned trees the second and third year after transplanting. Trees required, at most, 1 year per inch of trunk caliper to become established in the landscape.
Edward F. Gilman
This computer program, delivered-on a CD-ROM disc, develops a list of tree species and cultivars suited for a specific planting site. It requires little previous computer experience or tree knowledge to operate. Using multiple choice questions, the program automatically brings the user through above ground and below ground site analysis. This includes all the considerations known to influence proper species section for a planting site. Using C++ programming and the NASA-developed expert system shell called CUPS, a list of facts is generated as the user answers the questions. At the press of a button, the program finds trees that match the attributes the expert system placed on the facts list. The list can be further modified by choosing among ornamental and other tree attributes that might be of interest to the user. The tree list can be printed in several seconds. A typical run through the expert system takes 2 to 4 minutes to answer about 20 to 25 questions. The program contains data on 681 trees, more than 1,800 color photographs, and a 4-page fact sheet including 3 line drawings for each tree totaling more than 2,000 pages. The program can also be used as a reference by paging through the tree records to find information about specific trees. Each tree record lists on the computer monitor a large variety of data for the tree, allows you to view text about the tree, displays a line drawing of the entire tree, and displays up to seven photographs of each tree. The program will be distributed nationwide as a tool to help landscape architects, horticulturists and others select the right tree for the right place.
Edward F. Gilman
Due to the high cost of color separations, few plant materials texts have photographs and line drawings showing each plant at different times of the year and at different ages. CD-ROM computer technology allows the user ready access to this information at a reasonable cost. Horticulturists at the University of Florida have developed three CD-ROM discs for use throughout the U.S. The discs contain more than 3000 pages of text, extensive morphological characteristics and plant use suggestions, in addition to more than 2000 line drawings and nearly 3600 photographs of more than 1,800 plant species. Software developed for DOS and Windows allows the student to generate customized plant lists for landscape sites. Lists can be created to match specific site characteristics, desirable ornamental attributes, or both. Students can also use the programs to help identify unknown plant specimens. Other features allow viewing of insect and disease problems and access to up-to-date control recommendations.
Edward F. Gilman and James L. Green
Electronic information systems provide efficient information management—development, updating, storage, retrieval, and delivery. No more stockpiling of printed, going-out-of-date information when specific, concise, up-to-date information can be obtained just in time from the Internet. Authoring for electronic media is different than authoring for the printed page. To use unique characteristics of electronic information systems, information is presented in chunks, small units of information that can combine text, video, or sound to present one concept or to answer one question. A chunk may be linked to other chunks to provide definitions and further elaboration of terms or ideas. A chunk may be linked to related chunks to provide comprehensive information inquiry-driven by and tailored to the inquirer's interests and understanding. A chunk may be linked to other chunks to provide definitions and further elaboration of terms or ideas. Collaboration is facilitated by the World Wide Web (Web). Shared development reduces redundant efforts and costs and results in better products than can be produced by autonomous efforts. Continual, shared development and updating keep the individual chunks and the linked chunks (URLs) up-to-date and dynamic. Educators can thread (link) selected web modules or chunks (URLs) together into dynamic study assignments or dynamic textbooks for courses of study. To obtain the best of both media, CD-ROM software can be designed to interact with a Web site. The ways that CD-ROM and online are interacting are varied and evolving. Graphics-rich databases such as color photographs of plants or pests and related text that do not require continual updating are well suited to CD-ROM. Web links from the CD-ROM to additional, dynamic information and updates at the Web site keep the CD-ROM live and current. ASHS members are uniquely qualified to generate continually updated, peer-reviewed horticultural information on the web for continuous access by the interested learner whose pathway on the web will be inquiry-driven.
Edward F. Gilman and Michael E. Kane
Post-planting root development of red maple (Acer rubrum L.) on a well-drained site was compared with that on a site with a high water table. Container-grown red maple planted in 1985 were excavated in 1988 and cross-sectional root area (CSRA) calculated for roots >1 cm diameter, 5 cm beyond the edge of the original container rootball. Adventitious roots were generated in the field after planting, not in the container. Total adventitious CSRA was three times greater than CSRA of roots generated from the original container-produced root system. The number of adventitious roots (7.6) generated from the trunk and primary root after planting was greater than the number of roots originating from the existing root system (4.2). Adventitious root origin on both sites was within 5 cm of the soil surface, above the often circling, kinked, or twisted roots found within the container root ball. Four of the five largest roots were of adventitious origin. Root number, size, and growth rate were not modified by differences in cultural and environmental conditions between sites.
Michael D. Marshall and Edward F. Gilman
Quercus virginiana trees were container-grown (CG) or field-grown (FG) to a mean trunk diameter of 9.4 cm (3.7 inches), transplanted into sandy soil, and established with frequent or periodic irrigation. Three years after transplanting, trees were harvested with a 1.5-m- (60-inch-) diameter tree spade. Root number and root cross-sectional area was evaluated at the periphery of the tree spade-dug root ball. Despite similar increases in trunk diameter, FG trees had greater root number and root cross-sectional area than CG trees. The increase in root cross-sectional area occurred for roots 5 to 20 mm in diameter at the 0- to 25-cm and 75- to 100-cm soil depths. Irrigation frequency after transplanting had no effect on root number in FG trees; however, root number in CG trees decreased without frequent irrigation.
J. Roger Harris and Edward F. Gilman
Growth and physiological responses before and after transplanting to a simulated landscape were studied for `East Palatka' holly (Ilex ×attenuata Ashe `East Palatka') grown in plastic containers (PC), in the ground in fabric containers (FC), or in the ground conventionally. At the end of a 15-month production period, trees grown in PC had more shoot dry weight and leaf area than trees grown in FC, and they had thinner trunks than field-grown trees. Root balls on harvested field-grown trees contained 55% and those grown in FC 65% of total-tree root surface area. Trees transplanted from FC had the lowest predawn leaf xylem potential and required more frequent post-transplant irrigation than trees grown in PC or in the ground. Carbon assimilation rate and stomata1 conductance in the first week after transplanting were highest for trees planted from PC. Dry weight of regenerated roots was similar for all production methods 4 months after transplanting from the nursery, but trees grown in PC had SO% more regenerated root length, and the roots extended further into the back-fill soil.
Edward F. Gilman and Michael E. Kane
Shoot and root growth were measured on Chinese juniper (Juniperus chinensis L. `Torulosa', `Sylvestris', `Pfitzeriana', and `Hetzii') 1, 2, and 3 years after planting from 1l-liter black plastic containers. Mean diameter of the root system expanded quadratically, whereas mean branch spread increased linearly. Three years after planting, root spread was 2.75 times branch spread, and roots covered an area 5.5 times that covered by the branches. Percentage of total root length located within the dripline of the plants remained fairly constant for each cultivar during the 3 years following planting. Root length density increased over time but decreased with distance from the trunk. During the first 2 years after planting, shoot mass increased faster than root mass. In the 3rd year, the root system increased in mass at a faster rate than the shoots. Root length was correlated with root weight. Root spread and root area were correlated with trunk cross-sectional area, branch spread, and crown area.
Edward F. Gilman and Gregory L. Davis
Horticulturists can access an extensive library of data, text, photographs, line drawings, and landscape designs from CD-ROM. In tests conducted in Florida, classroom students successfully accessed this library in a computer lab to study plant identification. This made it unnecessary to duplicate slides for student self-learning. It also builds confidence in students' ability to use computers. The Cooperative Extension Service and Divisions of Forestry in the southern states also have enjoyed access to this technology. Customers of their services have been pleased with the quick access to reliable information. Most are pleased with the information received over the telephone or during their visit to the office. Information generated by the computer programs on CD-ROM has been faxed, mailed. or hand-delivered to customers. Cooperative Extension employees and Master Gardeners are pleased with the quick, easy access to information. Many report that the programs have replaced the need to page through a large number of books to gain access to plant information. This saves time and gives employees a renewed sense of pride in their work.
Edward F. Gilman and Michael E. Kane
Shoot and root growth were measured on Chinese juniper (Juniperus chinensis L.) Var. `Torulosa', `Sylvestris', `Pfitzeriana' and `Hetzii' 1, 2 and 3 years after planting into a simulated landscape from 10-liter black plastic containers. Mean diameter of the root system increased quadratically averaging 1, 2 m/year; whereas, mean branch spread increased at 0, 33 m/year, Three years after planting, root spread was 2, 75 times branch spread and roots covered an area 5.5 times that covered by the branches. Percentage of total root length located within the dripline of the plants remained fairly constant (71-77%) during the first 3 years following planting. Root length density per unit area increased over time but decreased with distance from the trunk. In the first 2 years after planting shoot weight increased faster than root `weight. However, during the third year after planting, the root system increased in mass and size at a faster rate than the shoots. Root length was correlated with root weight within root-diameter classes, Root spread and root area were correlated with trunk area, branch spread and crown area.