An Appraisal of the University of Tennessee Arboretum Holly Collection

Jim Cortese



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 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: (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 country.


KEY WORDS: Arboretum; Arboricultural; Arborists; Harold L. Elmore Holly Collection; Ilex Aquifoliaceae; Replacement Cost; Shrub/Small Tree Appraisal.


The University of Tennessee Forest Resources AgResearch and Education Center 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 (  The center includes three forest units located in East 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.  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.

In April 2008 the University of Tennessee Arboretum Society identified 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.

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 freeze, wind shear, tornados, flooding and drought; construction adjacent to the property, damage caused by visitors, insect and disease infestations. All of these were reasons for the need of a baseline appraisal that could be relatively simple and repeatable over time.



            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 – 9th 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 centimeters caliper or smaller.  The McMinnville area of Middle Tennessee is known as the wholesale tree nursery capital of the Southeast, where wholesale trees, shrubs and plants up to 20.3 centimeters caliper, can be purchased. The Elmore Holly Collection has over 200 trees and shrubs ranging from 13 – 132 liter container size, 0.6 – 5 meters tall, and 5.1 – 12.7 centimeters diameter.

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 collected.  However, no data could be found on some unusual and rare species in the collection; these plants were not listed and could not be found in the catalogues. At the same time, I was able to find many species of hollies and cultivars, both rare and common, 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 upon dimensional information confirmed in the nursery catalogues (Table 1).

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 meters and value was determined by size, independent of species or cultivar (Table 2).

Container grown holly stocks in a range of 4.4 – 132 liters 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.

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.  The determined average wholesale cost multiplied by the actual size of the holly plant in the Elmore 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).



This study method determined that the Elmore Holly Collection was valued at $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 followed 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.



            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:  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 Elmore Collection are not included in the appraisal of the collection.

The majority of the collection is in excellent condition.  Documenting changes throughout the years is essential to maintaining the health of the plants and preservation of the collection.  Each plant was assigned a optical condition rating of 1– 10 where 10 is excellent.  The average of this rating for the collection was 0.723.  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 second follow-up assessment was attempted to see if the results would be consistent with the first.  The second effort generated a value within two percent of the first effort following the same protocol. This protocol was repeatable in this arboretum collection and could be used in any other.

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.



            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 to maintain and improve the value of the collection.


 Table 1.  Nurseries Supplying Plant Dollar Values

Nursery                                                        Location    

Bold Springs Nursery                                  Monroe, GA

Cedar Row Nursery                                     Knoxville, TN

Creekside Nursery                                       Morrison, TN

Don Yancey & Sons Nursery                      McMinnville, TN

Flowerwood Nursery                                   Morrison, TN

Hidden Valley Nursery                                Viola, TN

Kinsey Gardens                                           Knoxville, TN

Little River Nursery                                     McMinnville, TN

Myers Cove Nursery                                    McMinnville, TN

Oak Brook Farms                                        Morrison, TN

Shadow Nursery                                          Winchester, TN

Shahan Brothers Nursery                                      Tullahoma, TN

Tennessee Bush Farm                                  McMinnville, TN

Trivetts Nursery                                           McMinnville, TN

Wanamaker Nursery                                    McMinnville, TN

Additional 2010 Nurseries

*Odom Nursery                                           Morristown, TN

*Stewart Nursery                                         McMinnville, TN

*Boyd & Boyd Nursery                               McMinnville, TN

*Hale & Hines Nursery                                McMinnville, TN

*Warren County Nursery                                      McMinnville, TN


Table 2.  Determination of Average Dollar Value of Holly Plants by Height

Plant Size (meter) (feet)          Number of Price Quotes         Average Dollar Value

0.6   – 0.91       2.1-3                           9                                  $23.50

0.92 – 1.22       3.1-4                          18                                  $32.50

1.23 – 1.52       4.1-5                         25                                  $42.00

1.53 – 1.83       5.1-6                         30                                  $57.00

1.84 – 2.15       6.1-7                         39                                  $88.00

2.16 – 2.46       7.1-8                         18                                  $115.00

2.47 – 2.76       8.1-9                         21                                  $154.00

2.77 – 3.07       9.1-10                       11                                  $184.00

3.08 – 3.66     10.1-12                        15                                  $285.00

3.67 – 4.27      12.1-14                         9                                  $417.00

4.28 – 4.88      14.1-16                         8                                  $508.00

4.89 – 5.49      16.1-18                         4                                  $585.00


Table 3.  Determination of Average Dollar Value of Containerized Holly Plants

        Liter Size  (Gal.)          Number of Price Quotes               Average Dollar Value

3.78       1                       23                                  $4.50

7.57       2                       27                                  $10.50

11.35      3                       22                                  $11.00

18.92      5                         9                                  $22.00

26.49      7                       15                                  $28.50

37.85    10                         3                                  $53.00

56.78    15                         6                                  $74.00

75.70    20                         3                                  $89.00

94.63    25                         2                                  $104.00

113.56    30                         2                                  $125.00


 Table 4.  Holly Valuation Summary

          Plant Size                      Average

Wholesale                   Number             Base

Height                          Holly Cost                  of Plants           Wholesale

(meter)             (feet)                                                                           Holly Value

0.6   – 0.91       2.1-3                $23.50                         4                      $94.00

0.92 – 1.22       3.1-4                $32.50                         13                    $422.50

1.23 – 1.52       4.1-5                $42.00                         18                    $756.00

1.53 – 1.83       5.1-6                $57.00                         16                    $912.00

1.84 – 2.15       6.1-7                $88.00                         14                    $1,232.00

2.16 – 2.46       7.1-8                $115.00                       10                    $920.00

2.47 – 2.76       8.1-9                $154.00                       10                    $1,540.00

2.77 – 3.07       9.1-10              $184.00                       10                    $1,840.00

3.08 – 3.66     10.1-12              $285.00                       12                    $3,420.00

3.67 – 4.27     12.1-14              $417.00                       10                    $4,170.00

4.28 – 4.88     14.1-16              $508.00                       16                    $8,128.00

4.89 – 5.49     16.1-18              $585.00                       5                      $2,925.00

5.50 – 6.10*   18.1-20              $673.00                       9                      $6,057.00

6.11 – 6.71     20.1-22              $776.00                       6                      $4,656.00

6.72 – 7.32     22.1-24              $890.00                       1                      $890.00

9.17 – 9.75     30.1-32              $1,558.00                    1                      $1,558.00

20.73-21.34   68-70     $22.184.00                              1                      $22,184.00

Plant Size (Liters) (Gal.)

7.57                         2              $7.50                           3                      $22.50

11.35                       3              $10.50                         5                      $52.50

18.92                       5              $22.00                         12                    $264.00

26.49                       7              $28.50                         8                      $228.00

37.85                     10              $53.00                         17                    $901.00

56.78                     15              $74.00                         7                      $518.00

94.63                    25              $104.00                       2                      $208.00

TOTAL                                                                                           **$63,898.50

*For trees greater than 18 feet, the value is increased by 15% per 2 ft. increment

**$63,898.50 x 0.723 (condition classification) = $46,198.62=

46,199.00 x 3 (standard wholesale-to-retail conversion factor) = $138,597.00



Council of Tree and Landscape Appraisers, 2000. Guide for Plant Appraisal (9th   Edition).


Jim Cortese

Consulting Arborist


P.O. Box 6416

Knoxville, TN 37914, U.S.

 [email protected]