J. For. 115(4):283–291 PRACTICE OF FORESTRY https://doi.org/10.5849/jof.15-097 measurement Building the Forest Inventory and Analysis Tree-Ring Data Set Robert J. DeRose, John D. Shaw, and James N. Long The Interior West Forest Inventory and Analysis (IW-FIA) program measures forestland conditions at great extent (USDA Forest Service 1999), for which re- with relatively high spatial resolution, including the collection of tree-ring data. We describe the development cent radial growth increment data was ob- of an unprecedented spatial tree-ring data set for the IW-FIA that enhances the baseline plot data by tained, and formed the basis for gross growth incorporating ring-width increment measured from increment cores collected on IW-FIA plots. Whereas the IW-FIA calculations. Since the national adoption of program has used increment cores consistent with traditional forestry (stand age, site index, and vigor), there the current mapped-plot design and the an- are key differences in sampling approaches between foresters and dendrochronologists. We describe a nualized inventory (Gillespie 1999), the framework for preparation, interpretation, and archiving of the IW-FIA tree rings. Early results suggest that the measurement of any plots originally estab- data produced by this framework are useful for growth-and-yield studies, stand dynamics, and dendroclima- lished under periodic inventories and re- tology. We discuss the potential for tree-ring data to become a standard component of the FIA program. We tained in the annual inventory design were also compare and contrast the applications and procedures of dendrochronology with the FIA approach and show again considered “initial visits” during the how the two sources of data complement one another. first cycle of annual inventory (e.g., see USDA Forest Service 2001, section 7-4). Al- Keywords: dendroclimatology, dendroecology, dendrochronological principles, forest inventory, tree-ring though periodic and annual inventories science were “bridged” by remeasuring some trees common to both inventory types, popula- tion-level growth estimation was largely ther articles in the Forest Inven- will enhance the core FIA data and provide tory and Analysis (FIA) special important ancillary data to previously exist- based on increment cores and not remea- section illustrate the history of the ing tree-ring data sets (DeRose et al. 2012, sured diameters during the first cycle of an- O nual inventory (O’Connell et al. 2015). FIA program and the evolution of the pro- 2013). gram into the diverse forest resource inven- Tree-ring data have been used to vari- With most states in remeasurement un- tory that it is today (e.g., Shaw et al. 2016, ous extents within the FIA program (e.g., der annual inventory, the need to calculate Thompson 2016). As has been the case Chojnacky 1997, Witt 2010). Stand age is a gross growth, using increment core-derived throughout the program’s history, this evo- core variable, and it is usually determined by growth measurements, has decreased sub- lution is ongoing, and the program contin- growth ring count and weighting of size stantially. Growth estimation on remea- ually strives to both provide a consistent core classes within a stand (US Department of sured FIA plots is based on outside bark re- data set and add components that can be Agriculture [USDA] Forest Service 2015). measurement, with the exception of certain used to address future information needs Tree age, combined with height measure- slow-growing species, for which the ex- (Goeking 2015). The collection, analysis, ments, also provides entry to site index pected measurement error for outside bark and archiving of tree-ring data is a recent and yield models used in the core data diameter is likely to be a large fraction of the addition to the Interior West Forest Inven- (O’Connell et al. 2015). Many periodic in- actual growth (e.g., woodland species) tory and Analysis (IW-FIA) program that ventories were made up of “initial” plot visits (Goeking et al. 2014, p. 13). For the excep- Received July 3, 2015; accepted February 3, 2016; published online March 17, 2016. Affiliations: Robert J. DeRose ([email protected]), USDA Forest Service, Forest Inventory and Analysis, Ogden, UT. John D. Shaw ([email protected]), USDA Forest Service. James N. Long ([email protected]), Utah State University. Acknowledgments: This research was supported in part by the Utah Agricultural Experiment Station, Utah State University, Logan, UT. Approved as journal paper no. 8879. This article was prepared in part by employees of the USDA Forest Service as part of official duties and is therefore in the public domain. This article was greatly improved by the comments of Sara Goeking and two anonymous reviewers. We extend thanks to many dendrochronologists who provided unpublished tree-ring data helpful to building our FIA data archive: Connie Woodhouse, Jeff Lukas, Stephen Gray, Matt Bekker, Jim Speer, Margaret Evans, and Stan Kitchen. Journal of Forestry • July 2017 283 tions, we anticipate that increment core velopment of an FIA-based tree-ring data ar- ysis to remount all cores. FIA crews usually measurements will continue to be used in chive, present an overview of results we have mounted the cores in the field for secure some capacity. Cores will also be obtained, obtained from preliminary analyses, de- transportation, and the purpose of collecting for example, when partial stand replacement scribe future potential applications, and dis- the cores was only to obtain tree age and requires recomputation of stand age. cuss the potential for tree-ring data to be- recent growth increment data. As a result, However, the utility of tree-ring data is come a standard component of the FIA the orientation of most cores on the laths not limited to the applications traditionally program. In the process, we also compare was not optimal for what is now considered used by the FIA program. The myriad uses and contrast the applications of “tradi- standard tree-ring measurement and analy- of tree-ring data are well known and funda- tional” dendrochronological data and proce- sis. Cores were correctly oriented and re- mental not only in the field of forestry, but dures with the FIA approach and show how mounted to accentuate the transverse sec- also in related fields such as geography and the two sources of data may complement tion and then sanded using progressively ecology (Cook and Kairiukstis 1990, Speer each other. finer grades of sandpaper, followed by a final 2010). Variations in diameter growth incre- hand polishing (Stokes and Smiley 1968). ment potentially record events of stand dy- Development of an FIA-Based This provides a surface suitable for viewing namics (Fritts and Swetnam 1989) and can Tree-Ring Archive under a microscope. be excellent proxies for past climate condi- The IW-FIA core collection was “dis- A protocol consistent with conventional tions (Fritts 1976). Annual tree-ring forma- covered” during moving activities in the tree-ring preparation techniques (Speer 2010) tion in mid- to high-latitude trees represents Ogden Forestry Sciences Laboratory in was developed to ensure proper processing, the integration of physiological traits and en- 2007. The cores were in various states labeling, crossdating, measurement, and ar- vironmental conditions (e.g., climate, soil, and of preservation, typically with the cores chiving of the FIA tree-ring data. In addition stand density) over the course of a growing glued to a grooved wood lath and boxed by to establishing a linkage with the FIA data- season and is influenced by previous grow- state and inventory. Most were labeled with base, we maintained metadata consistent ing seasons (Fritts 1976). Because of these the information essential to linking a core to with the International Tree-Ring Data Bank controls on ring width, tree rings are impor- the corresponding tree records in the FIA (ITRDB) so as to make the archive easily tant archives of past growing conditions and database: state, county, plot, species, and di- accessible to dendrochronologists and other can serve as a proxy for them if the drivers ameter. The FIA database contained no in- researchers after it is ready for publication. can be identified. In the early 20th century, formation indicating that the core for a Increment cores had to be initially cross-ref- the field of dendrochronology was estab- given tree was held in the collection, but the erenced with the FIA database to determine lished based solely on the analysis of tree- potential list of trees with cores could be in- origin and measurement year. Decadal dots ring data (Douglass 1909). For FIA, the po- ferred by the presence of an age value in the were labeled, in consultation with a local tential for deeper (i.e., preinventory) TREE or SITETREE tables. An informal chronology, before cores were measured on a chronological analysis means that tree rings sampling of several boxes suggested that sliding stage that is paired with a digital Ϫ Ϫ provide a valuable temporal context in there were approximately 12,000 cores, readout at 3.94 ϫ 10 5 or 3.94 ϫ 10 4 in. which current tree and forest growth could 90% of which were assessed as likely to be resolution. be related to historical growth. useable. After the establishment of agree- Arguably, the most important principle In 2009, the IW-FIA began a partner- ments between FIA and the USU Dendro- in dendrochronology is crossdating, which is ship with the Dendrochronology Labora- chronology Laboratory, all cores were moved to based on matching patterns in ring-width tory at Utah State University (USU) with the USU campus for processing. variability among multiple tree-ring series to the goal of advancing the use of tree-ring Shortly after beginning the archiving determine the actual year of ring formation.