Big Trees in the Southern Forest Inventory
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United States Department of Big Trees in the Southern Agriculture Forest Inventory Forest Service Southern Christopher M. Oswalt, Sonja N. Oswalt, Research Station and Thomas J. Brandeis Research Note SRS–19 March 2010 Abstract or multiple years. Listings of big trees encountered during the most recent forest inventory activities in the South Big trees fascinate people worldwide, inspiring respect, awe, and oftentimes, even controversy. This paper uses a modified version of are reported in this research note and should supplement American Forests’ Big Trees Measuring Guide point system (May 1990) existing lists and registers. to rank trees sampled between January of 1998 and September of 2007 on over 89,000 plots by the Forest Service, U.S. Department of Agriculture, For more than 75 years, the FIA Program has been charged Forest Inventory and Analysis Program in the Southern United States. Trees were ranked across all States and for each State. There were 1,354,965 by Congress to “make and keep current a comprehensive trees from 12 continental States, Puerto Rico, and the U.S. Virgin Islands inventory and analysis of the present and prospective sampled. A bald cypress (Taxodium distichum) in Arkansas was the biggest conditions of and requirements for the renewable resources tree (according to the point system) recorded in the South, with a diameter of the forest and rangelands of the United States” of 78.5 inches and a height of 93 feet (total points = 339.615). The tallest tree recorded in the South was a 152-foot tall pecan (Carya illinoinensis) in (McSweeney-McNary Act of May 22, 1928. 16 U.S.C. Mississippi (total points = 321.960), while the tree with the largest diameter 581) (Bechtold and Patterson 2005, Gillespie 1999). The was the bald cypress mentioned above. inventory conducted by FIA is a year-round effort to collect and disseminate information and statistics regarding the Keywords: Champion tree, circumference, FIA, height, Puerto Rico, U.S. Virgin Islands. extent, condition, status, and trends of forest resources across all ownerships (Smith 2002). Although FIA is a national program with national scope, FIA is implemented regionally by Forest Service research stations across the Big Trees of the South United States. In the South, the forest resources of 13 States (Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Big trees fascinate people worldwide. American Forests Mississippi, North Carolina, Oklahoma, South Carolina, describes big trees as “. symbols of all the good work Tennessee, Texas, and Virginia) and Puerto Rico are sampled trees do for the quality of the environment and our quality annually. About 20 percent of the forests in each State and of life” (American Forests 2008). Many State agencies commonwealth are sampled each year, while the U.S. Virgin maintain lists of statewide “champion” trees and supply Islands are sampled all in 1 year, resulting in a complete data to the National Register of Big Trees maintained inventory about every 5 years. and published by American Forests, a nonprofit citizens’ conservation organization (American Forests 2008). All but FIA applies a nationally consistent sampling protocol six U.S. States have designated a big tree champion in the using a quasi-systematic design covering all ownerships in American Forests registry. The U.S. Forest Service’s Forest the entire Nation (Bechtold and Patterson 2005). Here we Inventory and Analysis (FIA) Program is unique in the present summary tables from data collected on over 89,000 number of trees it measures throughout the course of a year permanent fixed-area plots installed across 12 Southern States (data for Oklahoma were not available at the time this manuscript was prepared), 1 commonwealth, and 2 U.S. territories in locations that have accessible forest land cover. Christopher M. Oswalt and Sonja N. Oswalt, Forest Resource Analysts, and Field crews collect data on > 300 variables, including land Thomas J. Brandeis, Supervisory Research Forester, U.S. Department of ownership, forest type, tree species, tree size, tree condition, Agriculture, Forest Service, Forest Inventory and Analysis Research Work Unit, Southern Research Station, Knoxville, TN 37919. and other site attributes, e.g., slope, aspect, disturbance, land All inventory data, with the exception of Puerto Rico and use (Smith 2002, U.S. Department of Agriculture 2007). the U.S. Virgin Islands, is stored in a publicly accessible Plot intensity for field-collected data is about one plot for database [Forest Inventory and Analysis Database (FIADB)]. every 6,000 acres of land (125,000 plots nationally) for the The data for this study came from FIADB version 3.0 for 12 Southern States and Puerto Rico, and every 500 acres for Southern States (Oklahoma data were unavailable). Data for the U.S. Virgin Islands. The plot design for FIA inventory Puerto Rico and the U.S. Virgin Islands were obtained from plots consists of four 24-foot fixed-radius subplots spaced local data servers. Data were accessed in August of 2008 120 feet apart in a triangular arrangement with one subplot (Texas data accessed February 2009). Tree information was in the center. All trees with a diameter at breast height of at recorded on 1,354,965 trees collected from January 1998 to least 5 inches are inventoried on forested subplots. Within September 2007 on over 89,000 plots. Reported inventory each subplot, a 6.8-foot microplot offset 12 feet from years for the data used ranged from 2000 to 2006. subplot center is established. All live-tree seedlings in each microplot are tallied according to species. Conifer seedlings American Forests’ champion tree criteria for measuring must be at least 6 inches tall with a root-collar diameter big trees (American Forests 2008) was used with slight < 1 inch. Hardwood seedlings must be at least 12 inches tall modifications (May 1990) to compile the southern FIA big with a root-collar diameter < 1 inch. tree lists. A “bigness” score was calculated for each tree by FIA Forester Jason P. Hewitt takes a few seconds out of the workday to pose next to a large baldcypress in Itawamba County, MS. 2 FIA Forester Sonja N. Oswalt stands in front of a large West Indian mahogany on the island of St. Croix, U.S. Virgin Islands. Photo by Thomas J. Brandeis. 3 FIA Forester John Simpson stops to pose near a large baldcypress in Mississippi after a long day in the field. awarding one point for each inch of a tree’s circumference on a diameter measurement taken about 1.5 feet above the at 4.5 feet above the ground and one point for every foot swell. This practice is suitable for meeting the needs of in height attained by the tree. American Forests’ scoring FIA, but underestimates the bigness score for those trees. system also awards one-quarter point for every foot of a Finally, a few trees are identified only at the genus level and, tree’s crown width (American Forests 2008). Unfortunately, therefore, genus level reporting is sometimes necessary. FIA does not collect crown width. As a result, the scores presented here do not reflect the full potential of each tree’s FIA takes many steps to ensure high-quality data is recorded bigness according to American Forests’ standards. However, in the field and continuously monitors data collection efforts due to the relatively small weight carried by crown width, with a strict quality assurance (QA) program. Each variable the scores should still provide meaningful and interesting collected must meet Measurement Quality Objectives assessments of tree size across the South. (MQO) set by the national FIA program, and MQO compliance is regularly assessed. The MQO consists of both Readers and users of the southern FIA big tree lists should a compliance standard and a measurement tolerance (see be mindful of several points first discussed by May (1990). Pollard and others (2006) for a detailed review of the FIA First, although > 1 million trees were measured for this QA program methodology). Three variables were utilized study, the sample still represents a fraction of the estimated for this study (species, d.b.h., and total length), and MQO 137 billion trees throughout the South. While the sample compliance in the southern States for each variable is listed is sufficient to meet the objectives of the FIA Program in in table A.1. the South, it is not sufficient to identify the largest trees in the area. Truly large trees are a rarity on the landscape, While the FIA QA program demands excellence through and a sample design with coarse-scale objectives is not the extensive training of nationally consistent protocols and most reliable tool to confidently identify all of the biggest procedures and continually measures MQO compliance, trees within the region. Second, for tree species with some measurement errors do occur. Moreover, the nature significant swell at the base, e.g. baldcypress (Taxodium of this study heightens the probability of influence from spp.) and tupelo (Nyssa spp.), the circumference is based measurement error due to the effort to identify extremes 4 within the database, i.e., the largest trees. To minimize the of the lists published in the study with the numerous big impact of measurement errors on the identification of “big” tree lists already released to the public may help identify the trees in this study, some species were removed from the potential for the existence of larger champion trees. published tables (table A.2). Most species were removed due to what appeared to be a species identification error The biggest trees measured by FIA in the southern (generally a keypunch error as a result of using electronic continental United States (not including Puerto Rico and data recorders in the field) identified as being outside of the U.S.