COMBINING HISTORIC AND CONTEMPORARY FIA DATA TO ASSESS LONG-TERM TRENDS: THE LONGLEAF PINE FOOTPRINT IN THE SOUTH William Burkman Christopher M. Oswalt Analysis completed with contributions from: Christopher W. Woodall Horace W. Brooks

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Outline Brief background Methods of Investigation Results Latitudinal/Longitudinal shifts Central range thinning Highlights from FIA assessment Comments on outlook Photo – Stephen F. Austin

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Background Longleaf pine forests were once – one of the most extensive ecosystems in North America (Landers and others 1995), occupying about 92 million acres in the southeastern United States (Frost 2006). Only a fraction of this longleaf pine remains today. The remaining longleaf pines are scarce, compared to their historical extent, and are spread among eight southern states in largely fragmented stands (longleaf pine is known to historically and currently occur in southeastern Virginia, however does not currently occur in the Forest Inventory and Analysis sample). Numerous studies recording the decline of Longleaf pine FIA Assessment of Longleaf Pine in the South (Oswalt et al. 2012) Use of historical data was needed for comprehensive assessment of changes Increase to 8.0 million acres

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Change in longleaf dominated stands – 1970’s to ’s percent7 percent Oswalt et al. In Press Longleaf pine = 3,300,717 LLP – Oak = 984,637

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES

Methods 1970’s vs Periodic, asynchronous inventories vs. Annual, continuous inventories Total Plots

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Methods – Forest type definitions Longleaf pine Longleaf pine occurs as a pure type comprises a majority of trees in the overstory Associates – Slash, loblolly and shortleaf pine, southern red oak, blackjack oak, water oak, persimmon, and sweetgum Sites – those areas that can and do burn on a periodic basis – usually occurs on middle and upper slopes with low severity brush or hardwood competition Longleaf pine – Oak Associates – Longleaf pine and scrub oaks – primarily turkey oak, bluejack oak, blackjack oak, and dwarf post oak Sites – Common on sandhills where soils are dry, infertile, and coarse- textured

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Graphical descriptions of forest types Longleaf pine forest type Longleaf pine – Oak forest type

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Combine Outer Range analysis techniques from Woodall et al. (2009) with longitudinal band analysis techniques from Kai et al. (2012). Woodall et al. (2008 and 2009) describes the inherent difficulty in comparing historical and contemporary FIA Inventories. Here we overcome those difficulties by: Greater electronic availability of historical data Not examining seedlings Greater similarity in periodic inventories within a single region No attempt made at linking causality to long-term phenomenon (changing climate) that would require a large span of time between inventories

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Methods Defining the “Outer Range” (sensu Woodall et al also see Zhu et al. 2012) 90 th & 10 th percentiles calculated based on 1970’s presence Eastern, Western, Southern, & Northern Outer Ranges (EOR, WOR, NOR, & SOR, respectively). Primary focus was on “Outer Ranges” – The “heart” of the LLP range was investigated further for changes in area et al.

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Methods Comparison between decades of: Mean latitude by 1 degree longitude classes Mean longitude by 1 degree latitude classes Welch’s two-sample t-test Comparison across decades of: Mean area Mean biomass Welch’s two-sample t-test Transformations Presentation of back-transformed metrics

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Mean Latitude – Longitude for 1970 & 2010

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Changes in Latitude Northern Outer Range Southern Outer Range

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Changes in Longitude Western Outer Range Eastern Outer Range

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES

Potential “Thinning”

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Potential “Bright side” of the story LLP forest type across the South (excluding VA)

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES From the FIA Assessment – Change in Diameter Distribution

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES Challenges to Using Historical Data Electronic Availability Regional differences in temporal richness of available data SRS – 1970’s NRS – 1980’s RMRS – 1980’s PNWRS – 1990’s Temporal Consistency of Variables Great example – collection of seedling data Many others Temporal Consistency of Inventory Design Multiple designs Changes, Changes, Changes None of these challenges are insurmountable. However, all of these challenges impact the strength of inferences that can be made and the confidence in those inferences. State1970’s1980’s1990’s AL AR FL , GA , 1989 LA MS NC OK (East) SC TN 1980, 1989 TX (East) VA SC 1968 also available electronically VA 1984 renamed 1985

L ONGLEAF P INE IN THE S OUTHERN U NITED S TATES CONCLUSION Combination of Woodall’s “Outer Range” and Zhu’s “Longitudinal Bands” Longleaf pine “footprint” has contracted since 1970 Most significant contraction in Northeast of range “Rebounding” from low may be occurring FIA data and analyses good at helping identify large-scale conservation issues – not so good (in many cases) at identifying cause and effect

William BurkmanChristopher M. Oswalt Knoxville, TN