Assessing horizontal accuracy of inventory plots in forests with different mix of tree species composition and development stageš V., Sačkov I., Sedliak M., Tunák D., Chudý F. (2018): Assessing horizontal accuracy of inventory plots in forests with different mix of tree species composition and development stage. J. For. Sci., 64: 478-485.
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Global navigation satellite systems (GNSS) have a wide range of applications in forest industry, including forest inventory. In this study, the horizontal accuracy of 45 inventory plots in different forest environments and 5 inventory plots under open sky conditions were examined. The inventory plots were located using a mapping-grade GNSS receiver during leaf-on season in 2017. True coordinates of the plot centres were acquired using a survey-grade GNSS receiver during leaf-off season in 2018. A study was conducted across a range of forest conditions in the forest unit Vígľaš, which is located in Slovakia (Central Europe). Root mean square error of horizontal accuracies was 8.45 m in the plots under forest canopy and 6.61 m under open sky conditions. We note decreased positional errors in coniferous forests as well as in younger forests. However, results showed that there is no statistically significant effect of tree species composition and stand age on horizontal accuracy.

Awange J.L. (2012): Environmental Monitoring Using GNSS: Global Navigation Satellite Systems. Heidelberg, Springer Science & Business Media: 382.
Bettinger P., Fei S. (2010): One year’s experience with a recreation-grade GPS receiver. Mathematical and Computational Forestry & Natural-Resource Sciences, 2: 153–160.
Bettinger P., Merry K.L. (2012): Influence of the juxtaposition of trees on consumer-grade GPS position quality. Mathematical and Computational Forestry & Natural-Resource Sciences, 4: 81–91.
Bolstad P., Jenks A., Berkin J., Horne K., Reading W.H. (2005): A comparison of autonomous, WAAS, real-time, and post-processed global positioning systems (GPS) accuracies in northern forests. Northern Journal of Applied Forestry, 22: 5–11.
Brach M., Zasada M. (2014): The effect of mounting height on GNSS receiver positioning accuracy in forest conditions. Croatian Journal of Forest Engineering: Journal for Theory and Application of Forestry Engineering, 35: 245–253.
Deckert C., Bolstad P.V. (1996): Forest canopy, terrain, and distance effects on global positioning system point accuracy. Photogrammetric Engineering and Remote Sensing, 62: 317–321.
D'Eon Stephen P. (1995): Accuracy and signal reception of a hand-held Global Positioning System (GPS) receiver. The Forestry Chronicle, 71, 192-196
Hasegawa Hisashi, Yoshimura Tetsuhiko (2017): Application of dual-frequency GPS receivers for static surveying under tree canopies. Journal of Forest Research, 8, 103-110
Hoppus M., Lister A. (2007): The status of accurately locating forest inventory and analysis plots using the Global Positioning System. In: McRoberts R.E., Reams G.A., Van Deusen P.C., McWilliams W.H. (eds): Proceedings of the Seventh Annual Forest Inventory and Analysis Symposium, Portland, Oct 3–6, 2005: 179–184.
Johnson Chris E., Barton Christopher C. (2004): Where in the world are my field plots? Using GPS effectively in environmental field studies. Frontiers in Ecology and the Environment, 2, 475-482[0475:WITWAM]2.0.CO;2
Karsky D. (2004): Comparing Four Methods of Correcting GPS Data: DGPS, WAAS, L-band, and Postprocessing. Tech Tip 0471-2307-MTDC. Missoula, USDA Forest Service, Missoula Technology & Development Center: 6.
Kitahara F., Mizoue N., Kajisa T., Murakami T., Yoshida S. (2010): Positional accuracy of national forest inventory plots in Japan. Journal of Forest Planning, 15: 73–79.
Mauro F., Valbuena R., García A., Manzanera J. (2009): GPS admissible errors in positioning inventory plots for forest structure studies. In: Proceedings of the IUFRO Division 4 Meeting: Extending Forest Inventory and Monitoring over Space and Time, Quebec City, May 19–22: 5.
Naesset E., Bjerke T., Bvstedal O., Ryan L.H. (2000): Contributions of differential GPS and GLONASS observations to point accuracy under forest canopies. Photogrammetric Engineering & Remote Sensing, 66: 403–407.
Piedallu C., Gégout J.C. (2005): Effects of forest environment and survey protocol on GPS accuracy. Photogrammetric Engineering & Remote Sensing, 71: 1071–1078.
Rodríguez-Pérez José R., Álvarez M. F., Sanz-Ablanedo Enoc (2007): Assessment of Low-Cost GPS Receiver Accuracy and Precision in Forest Environments. Journal of Surveying Engineering, 133, 159-167
Sigrist P., Coppin P., Hermy M. (2010): Impact of forest canopy on quality and accuracy of GPS measurements. International Journal of Remote Sensing, 20, 3595-3610
Tomaštík Julián, Tomaštík Julián, Saloň Šimon, Piroh Rastislav (): Horizontal accuracy and applicability of smartphone GNSS positioning in forests. Forestry, , -
Topcon (2018a): FC-25/FC-25A field controller. Available at (accessed Aug 24, 2018).
Topcon (2018b): Hiper GD & Hiper GGD Operator’s Manual. Available at (accessed Aug 24, 2018).
Tuček J., Ligoš J. (2002): Forest canopy influence on the precision of location with GPS receivers. Journal of Forest Science, 48: 399–407.
Valbuena R., Mauro F., Rodriguez-Solano R., Manzanera J. A. (2010): Accuracy and precision of GPS receivers under forest canopies in a mountainous environment. Spanish Journal of Agricultural Research, 8, 1047-
Weaver Steven A., Ucar Zennure, Bettinger Pete, Merry Krista, Schumann Guy J-P. (2015): How a GNSS Receiver Is Held May Affect Static Horizontal Position Accuracy. PLOS ONE, 10, e0124696-
G. Wing Michael (2011): Consumer-Grade GPS Receiver Measurement Accuracy in Varying Forest Conditions. Research Journal of Forestry, 5, 78-88
Wing Michael G., Eklund Aaron, Kellogg Loren D. (2005): Consumer-Grade Global Positioning System (GPS) Accuracy and Reliability. Journal of Forestry, 103, 169-173
Wing M.G., Eklund A., John S., Richard K. (2008): Horizontal measurement performance of five mapping-grade global positioning system receiver configurations in several forested settings. Western Journal of Applied Forestry, 23: 166–171.
Xu G., Xu Y. (2016): GPS: Theory, Algorithms and Applications. 3rd Ed. Berlin, Springer: 489.
Yoshimura Tetsuhiko, Hasegawa Hisashi (2017): Comparing the precision and accuracy of GPS positioning in forested areas. Journal of Forest Research, 8, 147-152
Zald Harold S.J., Ohmann Janet L., Roberts Heather M., Gregory Matthew J., Henderson Emilie B., McGaughey Robert J., Braaten Justin (2014): Influence of lidar, Landsat imagery, disturbance history, plot location accuracy, and plot size on accuracy of imputation maps of forest composition and structure. Remote Sensing of Environment, 143, 26-38
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