Abstract
Maintaining land resources for research and education requires sound stewardship. These environments are affected by factors that can impact the health and benefits of the property. The University of Tennessee Forest Resources AGResearch and Education Center (Knoxville, Tennessee, U.S.) includes an arboretum of 101 hectares. Established in 1965, this section of the Oak Ridge Forest includes more than 2,500 native and exotic woody plant specimens. Identifying the value of the collections was necessary for determining the extent of resources that should be dedicated to its upkeep. Should weather, infestations, and other occurrences damage the property, replacement values need to be accurate. The Elmore Holly Collection was the only section that had not been appraised. This study examined the Ilex aquifoliaceae to appraise the current value of the collection. The objectives were to 1) identify the best appraisal method, and 2) apply that method to every holly plant in the collection to determine the total value. The traditional appraisal methods did not suit the study. A slight modification of the Replacement Cost Method was found to be the best approach. The method was repeated to confirm accuracy of the appraisal. The modified valuation method provides a tool that gives practical application of a research method to use in collection appraisals and is repeatable in all sections of the United States.
The University of Tennessee Forest Resources AgResearch and Education Center (Knoxville, Tennessee, U.S.) consists of 4,613.5 hectares. The mission of the center aims to 1) provide the land and supporting resources necessary for conducting modern and effective forestry, wildlife, and associated social, biological, and ecological research programs; 2) demonstrate the application of optimal forest and wildlife management technologies; and 3) assist with transfer of new technology to forest land owners and industries (forestry.tennessee.edu). The center includes three forest units in eastern and middle Tennessee: 1) Oak Ridge Forest, 2) Cumberland Forest, and 3) Highland Rim Forest.
The Oak Ridge Forest was established in 1964 and boasts 891 hectares, with 101 of these hectares dedicated in 1965 as an arboretum to provide public education and public service (Figure 1). The arboretum has a collection of more than 2,500 native and exotic woody plant specimens. Interpretive nature trails and ecological points of interest support ongoing research and educate the public about environmental and land-use stewardship.
The Elmore Holly Collection boasts hollies native to Europe, Asia, and the United States.
In April 2008, the University of Tennessee Arboretum Society determined that the only task remaining to determine the total value of contributions received since its inception was to assess the present-day value of the holly collection. The holly is a part of the aquifoliaceae family, within the Ilex genus. Aquifoliaceae include more than 400 species and can be evergreen and deciduous trees, shrubs and climbers, and typically have needle-point leaves with serrated edges and small berries that are usually red but also can be orange, brown, or black.
Beginning in 1985, holly grower Harold Elmore introduced the major collection of hollies to the arboretum. He acquired many of the plants from the Holly Society of America and from cuttings he propagated as a grower. Elmore donated all of the original collection, and since his passing in 2002, new plants have been acquired from nurserymen associated with the Holly Society and retail nurseries. The Harold L. Elmore Holly Collection has hollies native to Europe, Asia, and the U.S., including many varieties native to Tennessee. The Holly Society of America recognizes the Elmore Holly Collection as an official Holly Arboretum. The Elmore Holly Collection has over 200 trees and shrubs, ranging from 13–132 L container size, 0.6–5 m tall, and 5.1–12.7 cm diameter.
To achieve the University’s goal of valuing the hollies, an appraisal of the holly trees and shrubs was essential for current and future budgetary, planning, maintenance, and insurance considerations. Some conditions that affect the health of the collection are variable: weather (such as freezing conditions, wind shear, tornados, flooding, and drought), construction adjacent to the property, damage caused by visitors, and insect and disease infestations. All of these were reasons for the need of a baseline appraisal, which needed to be relatively simple and repeatable over time.
MATERIALS AND METHODS
A number of methods offer the means to determine tree and plant values. The major source of plant valuation information and guidance in the United States is the Council of Tree and Landscape Appraisers’ Guide for Plant Appraisal (ninth edition).
Based upon the criteria, the Replacement Cost Method, with slight modification, presented the most practical method to appraise the holly collection. This method was used for trees that are considered to be of replaceable size, usually 20.3 cm caliper or smaller. The McMinnville area of middle Tennessee is known as the wholesale tree nursery capital of the southeastern U.S., where wholesale trees, shrubs, and plants up to 20.3 cm caliper can be purchased.
A review of nursery catalogues was helpful to establish the base wholesale cost of transplantable plant materials. By doing this, most of the species in the arboretum were identified, and cost data were collected. There were some unusual and rare species in the collection for which no data could be found; these plants were not listed. At the same time, many species of hollies and cultivars, including rare ones, were found in the catalogues that were not in the arboretum collection.
To solve this conundrum, hypothetical holly trees and shrubs of all species and cultivars listed in the catalogues were created based upon field and container size. Values were determined based on dimensional information confirmed in the nursery catalogues (Table 1).
Nurseries supplying plant dollar values (USD$).
Comparative holly values in the nursery market catalogues were based on two criteria: height grades for field-grown stocks, and by container size for non-field-grown stocks. The heights for field-grown stocks ranged from 0.6–5 m, and value was determined by size, independent of species or cultivar (Table 2).
Determination of average dollar value of holly plants by height.
Container-grown holly stocks in a range of 4.4–132 L were developed, with tree-form size in containers ranging from 5–12 cm caliper; values were assigned by container size regardless of species or cultivar (Table 3). Container-grown caliper was not used in the valuation process of this case.
Determination of average dollar value of containerized holly plants.
Mean size class values were developed from the surveyed nursery wholesale pricing structures. This produced the average cost of a holly in each size category, regardless of its specific species or cultivar.
A committee of three from the U.T. arboretum board ocularly assessed the condition of the hollies in the collection. Each plant was assigned an optical condition rating of 1–10, where 10 is excellent. The majority of the collection is in excellent condition. The average of this rating for the collection was 7.3. This number was converted to 73%, or 0.73, and multiplied by the determined wholesale value of the plants. The collection wholesale value was discounted by this amount to take into consideration the condition of the plants at the time of inspection and measurement.
The determined average wholesale cost of each plant multiplied by the actual size of the holly plants in the Elmore Holly Collection resulted in a wholesale price of the collection. Summarizing these costs provided a wholesale price of the entire collection. Multiplying the wholesale value by three, an industry standard conversion factor identified the retail replacement value of the collection (Table 4).
Holly valuation summary.
RESULTS
This study method determined that the Elmore Holly Collection was valued at USD $138,597 in 2008, an average of $660 per plant. A subsequent assessment, independent from this initial study, conducted in 2010 showed a value of $140,841, an average value per holly of $671. This is a 1.7% increase from the first appraisal. This follow-up assessment used the same protocol as the 2008 assessment. New, 2010 nursery wholesale price lists were ordered from the same and other nurseries in the McMinnville area, and all hollies were broken down and placed into the previously determined categories.
DISCUSSION
The Elmore Holly Collection is a significant property. The oldest tree in the collection is Ilex verticillata, commonly known as winterberry. There are 216 holly species and cultivars in the collection: 18% are Ilex opaca; 15% are Ilex cornuta; 10% Ilex crenata; 8% Ilex aquifolium; 7% Ilex verticillata; and the other 42% is miscellaneous. Additional hollies planted circa 1965 along the drive to the collection were not included in the appraisal of the collection.
The second, follow-up assessment was attempted to see if the results could be replicated, and would be consistent with the first. The second effort generated a value within two percent of the first effort and had followed the same protocol. This protocol was repeatable in this arboretum collection and could be used in others.
The specific modification to the Replacement Cost Method of appraisal is the creation and use of hypothetical plants instead of the actual plants in the arboretum collection. The analysis of nursery plants included standard hollies and some rare species and cultivars.
CONCLUSION
Despite gaps of information regarding specific species and their values, the Replacement Cost Method, with modification, presented acceptable results. Another review two years later drew values that confirmed accuracy and ability to replicate the method in the future. The University of Tennessee Arboretum offers significant research, education, and public service throughout its properties. The method applied in this appraisal proved to be reliable and provides a baseline for researchers to maintain and improve the value of the collection.
- © 2018, International Society of Arboriculture. All rights reserved.
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