Trees on K-12 School Campuses in Virginia

Trees and saplings growing on K-12 school campuses were investigated in 105 school districts across Virginia. There were 2812 trees (>12.5 cm stem diameter at 1.4 m above ground level) inventoried across all campuses. The mean and median campus tree population was 27 and 18, respectively. Lob lolly pine (Pinus taeda L.) was the most abundant species, accounting for 11 % of all inventoried trees. Red maple (Acer rubrum L.) was the most frequently inventoried species, present on 44% of the campuses. Sapling (trees with 2.5-12.5 cm stem diameter at 1.4 m above ground level) populations were similar to tree populations. The mean and median campus sapling population was 23 and 13, respectively. Flowering dogwood (Cornus florid a L.) and red maple were the most abundant sapling species, each accounting for about 10% of all inventoried saplings. Flowering dogwood, red maple, Bradford pear (Pyrus calleryana Decne. 'Bradford'), willow oak (Quercus phellos L.), and ornamental cherry (Prunus spp.) were the most frequently inventoried sapling species, each present on more than 25% of the campuses. Across all campuses, species diversity was relatively low: less than 10 species accounted for over 50% of the inventoried trees and saplings. Prominent Virginia natives, in particular Carya and Quercus species, were under represented in the inventory. INTRODUCTION Urban forests are increasingly recognized for their ecological and societal benefits (Kane and Kirwan 2005). Trees in the urban forest improve air quality, protect watersheds, sequester carbon, and reduce energy consumption for heating and cooling buildings. In addition, properly designed and maintained urban vegetation has been linked to reduced crime (Kuo and Sullivan 2001), enhance cognitive development of children (Wells 2000), and job satisfaction (Kaplan et al. 1988). As the U.S. population grows and becomes more urbanized, urban forests will play an increasingly important role in environmental sustainability and quality of life. From 1910 to 2000, the urban segment of the U.S. population increased from 28% to 80% (Hobbs and Stoops 2002). By 2030, 87% of the U.S. population (projected to exceed 370 million) will live in urbanized areas (UNESA 2004) . The population of Virginia (currently about 7.5 million) is projected to reach 9.8 million by 2030 (U.S. Census Bureau 2005). In the Chesapeake Bay watershed alone, residential development is projected to consume 800,000 acres of land between 2003 and 2030 (Boesch and Greer 2003). This pattern and rate of population growth will place unprecedented strain on natural resources. Healthy, well-managed urban forests may be a key component of sustainable community growth. In 1998, the Virginia Tech Department of Forestry began an outreach program to teach dendrology, forest biology, and forest management concepts to K-12 students and Virginia Journal of Science, Vol. 58, No. 1, 2007 https://digitalcommons.odu.edu/vjs/vol58/iss1 4 VIRGINIA JOURNAL OF SCIENCE other public audiences. The program was initiated to help address a nationwide decline in science achievement during the middle school years (Calsyn et al. 1999) and to help Virginia teachers meet their Standards of Learning (SOL) objectives (Board of Education 2003). The program has been delivered through a dedicated web site (http://www.cnr.vt.edu/dendro/forsite /contents.htm), classroom presentations by Virginia Tech undergraduate students, and internet-based scientific investigations conducted by K-12 students (Kirwan and Seiler 2005). Now in its eighth year, the outreach program has spanned across three states and reached nearly 15,000 K-12 students at 83 schools and numerous 4-H clubs. As part of the outreach program, tree inventories were conducted on school campuses. From these inventories, school tree lists were compiled and placed on the program website. Dendrology fact sheets and an online dichotomous key developed by the Virginia Tech Department of Forestry were linked to the tree lists to facilitate student learning about tree identification and forest biology. In compiling the tree lists, a wealth of information has emerged on the composition of campus tree populations. Trees are a valuable asset on school campuses. They not only provide important environmental benefits such as shade and storm water abatement, but are also a valuable, yet often overlooked, resource to teach students about ecology and stewardship. Perhaps more important, the composition of campus tree populations is arguably a reflection of local knowledge, attitudes, and values regarding trees on public property. In most localities, the same biological, sociopolitical, and economic forces that influence tree preservation and planting on school campuses similarly impact other public properties. For these reasons, campus tree inventories can provide insight into natural resource management and education efforts in Virginia. The purpose of this paper is to report key findings from these campus tree inventories and discuss the implications for future management and education efforts. MATERIALS AND METHODS From 2000 to 2005, the lead author, with assistance from local students, teachers, and extension agents, conducted tree inventories on K-12 school campuses across Virginia. Tree inventories were conducted at schools where outreach educational programs were conducted or where there was a request to compile a school tree list. To obtain a broad geographical representation, inventory data from only one school campus in each of 105 school districts were analyzed in this study (Appendix 1 ). In school districts where more than one campus was inventoried, the school that was first in alphabetical order was selected for this study. The majority of tree inventory data used in this study was collected at public elementary schools (91 of 105 campuses). The balance came from middle school (10), high school (1 ), or combined (2) campuses. One private elementary school campus was also inventoried. The inventories were limited to trees growing in maintained campus areas. Boundary line trees and trees in campus natural areas were not inventoried. The species and stem diameter at breast height (DBH-measured 1.4 m above ground level) were determined for each inventoried tree. For multi-stemmed trees that divided below 1.4 m, the individual stem diameters were summed. Trees :s:: 12.5 cm DBH were designated as saplings in the inventory. Trees <2.5 cm DBH were not inventoried. Species abundance, frequency, and importance metrics were calculated using the SCHOOL CAMPUS TREES 5 TABLE 1. Statistics describing tree (> 12.5 cm stem diameter at 1.4 m above ground level) and sapling (trees with 2.5-12.5 cm stem diameter at 1.4 m above ground level) populations inventoried on 105 Virginia school campuses during 2000-2005. Campus Plant Count Campus Species Richness Trees Minimum 0 0 25th Percentile 8 3 Median 18 6 Mean 27 7 75th Percentile 39 9 Maximum 162 23 Total 2812 100 Saplings Minimum 0 0 25th Percentile 6 3 Median 13 5 Mean 23 6 75th Percentile 25 8 Maximum 196 22 Total 2431 103 combined inventory data. Each metric was calculated separately for trees and saplings. Species abundance was calculated as the number of plants of a given species divided by the total number of plants in the inventory. Species frequency was calculated as the number of campuses where a species was inventoried divided by the total number of campuses inventoried. Abundance and frequency values were multiplied by 100 and expressed as percentages. Species importance was calculated as the sum of the abundance and frequency percentages. The importance metric was developed as a simple way to communicate both the preponderance and geographic distribution of a species. A high importance value does not necessarily imply that a species has high ecological or economic value. Rather, the importance metric reveals patterns in tree preservation and tree planting on school campuses that are not discernable from the abundance and frequency metrics alone. RESULTS Trees There were 2812 trees inventoried across the 105 school campuses (Table 1 ). The mean and median campus tree population was 27 and 18, respectively. Three campuses each had over 100 inventoried trees (Figure 1 ). Conversely, nine campuses had no inventoried trees . About one-fourth of the campuses had eight or fewer inventoried trees. There were 100 tree species, representing 52 genera, inventoried across the 105 school campuses. On average, there were seven different species on each campus. \ Virginia Journal of Science, Vol. 58, No. 1, 2007 https://digitalcommons.odu.edu/vjs/vol58/iss1 6 VIRGINIA JOURNAL OF SCIENCE