Abstract
The U.S. General Land Office land surveys document trees present during European settlement. However, use of these surveys for calculating historical forest density and other derived metrics is limited by uncertainty about the performance of plotless density estimators under a range of conditions. Therefore, we tested two plotless density estimators, developed by Morisita and Pollard, for two, three, and four trees per survey point under simulated ranges of tree densities, non-uniform densities, and different tree spatial distributions. Based on these results, we developed estimator corrections and determined number of survey points needed for reliable density estimates. The Morisita estimator was accurate for densities ranging from 5 to 1,000 trees per unit area, non-uniform densities, random and regular spatial distribution, and outperformed the Pollard estimator. Estimators using points with two or three trees did need a simple correction to account for overestimation. Likewise, for clustered distributions, depending on the number of trees per survey point and the amount of clustering, there should be adjustment for a range of under and overestimation. Sample sizes for survey points with three or four trees should be at least 200 survey points, and 1,000 survey points will have density estimates within ±10% tolerance range of actual density. For survey points with two trees, the minimum sample size should be 600 survey points, and 2,000 survey points should be the target value. These results provide guidelines for researchers to improve density estimates of historical forests.
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References
Almendinger JC (1996) Minnesota’s bearing tree database. Minnesota Department of Natural Resources, St. Paul, Minnesota
Bolliger J, Mladenoff DJ (2005) Quantifying spatial classification uncertainties of the historical Wisconsin landscape (USA). Ecography 28:141–156
Bouldin J (2008) Some problems and solutions in density estimation from bearing tree data: a review and synthesis. J Biogeogr 35:2000–2011
Bourdo EA (1956) A review of the General Land Office survey and of its use in quantitative studies of former forests. Ecology 37:754–768
Cottam G, Curtis JT (1956) The use of distance measures in phytosociological sampling. Ecology 37:451–460
He HS, Mladenoff DJ, Sickley T, Guntenspergen GG (2000) GIS interpolations of witness tree records (1839–1866) for northern Wisconsin at multiple scales. J Biogeogr 27:1031–1042
Kronenfeld BJ, Wang Y-C (2007) Accounting for surveyor inconsistency and bias in estimation of tree density from presettlement land survey records. Can J Forest Res 37:2365–2379
Leitner LA, Dunn CP, Guntenspergen GR, Stearns F, Sharpe DM (1991) Effects of site, landscape features, and fire regime on vegetation patterns in pre-settlement southern Wisconsin. Landscape Ecol 5:203–217
Morisita M (1957) A new method for the estimation of density by the spacing method, applicable to non-randomly distributed populations. Seiri Seitai 7:134–144 (in Japanese)
Nelson JC (1997) Presettlement vegetation patterns along the 5th principal meridian, Missouri territory, 1815. Am Midl Nat 137:79–94
Pollard JH (1971) On distance estimators of density in randomly distributed forests. Biometrics 27:991–1002
Rhemtulla JM, Mladenoff DJ, Clayton MK (2009) Historical forest baselines reveal potential for continued carbon sequestration. PNAS 106:6082–6087
Schulte LA, Mladenoff DJ, Burrows SN, Sickley TA, Nordheim EV (2005) Spatial controls of pre-Euro-American wind and fire disturbance in northern Wisconsin (USA) forest landscapes. Ecosystems 8:73–94
Ward RT (1956) The beech forests of Wisconsin: changes in forest composition and the nature of the beech border. Ecology 37:407–419
White CA (1983) A history of the rectangular survey system. Bureau of Land Management, Government Printing Office, Washington DC, USA
Acknowledgments
We thank William Dijak for programming assistance. Support was provided by the National Fire Plan and the USDA Forest Service, Northern Research Station.
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Hanberry, B.B., Fraver, S., He, H.S. et al. Spatial pattern corrections and sample sizes for forest density estimates of historical tree surveys. Landscape Ecol 26, 59–68 (2011). https://doi.org/10.1007/s10980-010-9533-7
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DOI: https://doi.org/10.1007/s10980-010-9533-7