FORMATH TACHIKAWA 2010 (the 10th Anniversary Forest Resource Management and Mathematical Modeling International Symposium), Tachikawa, Japan, 13 Mar. 2010

1. Using global positioning system (GPS) technology for tree marking in a natural forest under single-tree selection system Owari, T., Kimura, N., Shimizume, M., Takuma, R., Nakagawa, Y. and Tookuni, M. (Univ. of Tokyo, Japan)

2. Single-tree Selection System … is an uneven-aged silvicultural system under which trees are selected to be cut individually from a large area periodically (Zingg et al., 1999) … has been employed in Hokkaido, northern Japan, since the early 20th century as a major option for natural forest management (Yoshida et al., 2006) 2010/03/13 FORMATH2010 (T. Owari) 2

3. Tree Marking … involves the careful selection of trees for harvest according to forest management objectives (OMNR, 2004) … is an essential technique in single-tree selection system (Owariet al., 2010) … affects the growth, quality and regeneration of a stand 2010/03/13 FORMATH2010 (T. Owari) 3

4. Using GPS for Tree Marking Practically, a tree marker makes a marking decision The information on “where marked trees were located” has not been available Recent advances in GPS technology enable us to pinpoint the geographic location of marked trees (Tsuyukiet al., 2006) 2010/03/13 FORMATH2010 (T. Owari) 4

5. Purpose This paper presents practical applications of GPS technology to tree marking in single-tree selection forest management A case study was conducted at the University of Tokyo Hokkaido Forest Topics include: Positional accuracy of a handy GPS receiver during tree marking Mapping the location of marked trees Spatial analyses of tree marking (spatial query, point density) 2010/03/13 FORMATH2010 (T. Owari) 5

6. Study Site Sub-compartment 66A, the UT Hokkaido Forest Location:Furano city (43º 16 – 17´ N, 142º 28 – 29´ E, 370 – 400 m a.s.l.) Area: 106.27 ha, of which 29.23 ha were selection cutting stand Terrain: flat Growing stock in selection stand: 7,286 m3 (249 m3 ha-1), 899 trees ha-1 2010/03/13 FORMATH2010 (T. Owari) 6

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8. Tree Marking in the Study Site During April - May 2008 (defoliated season) Rate of removals: 16 % of the standing volume Designated: 1,166 m3 (40 m3/ha) Actual: 1,146 m3 (98% of the designated harvest) A total of 1,565 trees were selected and marked to be cut 2010/03/13 FORMATH2010 (T. Owari) 8

9. Data Collection GPS receiver GPSMAP 60CSx (Garmin Ltd.) Small, handy, and easy to use Relatively easy GPS signal reception in a forested area (Tsuyukiet al., 2006) Marking the location (waypoint) Stand at 30 cm from the stem Stay shortly Press “MARK” and “ENTER” 2010/03/13 FORMATH2010 (T. Owari) 9

10. Data Processing Mapping of marked trees Save the waypoints as a .gpx file (GPS eXchange Format) Convert to a .shp file (ESRI Shapefile) using the gpx2shp file converter Convert map projection from WGS1984 to JGD2000 using ArcGIS 9.3 Positional accuracy Positional error (d): True coordinates (Xtrue, Ytrue) of 43 points were obtained through a traverse survey with a laser rangefinder Impulse200, Mapstar compass module (LTI Inc.), and a static GPS survey with a ProMark 3 receiver (Magellan Navigation, Inc.) Spatial analysis (ArcGIS 9.3; n=1,565) Using “select by location”, trees that intersect with polygon features of selection cutting stand were determined Spatial distribution of harvest intensity was identified by calculating “point density” (circular neighborhood; r = 17.84 m, cell size; 10 m) 2010/03/13 FORMATH2010 (T. Owari) 10

11. Results 2010/03/13 FORMATH2010 (T. Owari) 11

12. 2010/03/13 FORMATH2010 (T. Owari) 12 Locations of marked trees (n = 43) By GPSMAP 60CSx receiver By the traverse survey Ratio of closure 1/6003 (north) and 1/367 (south)

13. Positional Error 2010/03/13 FORMATH2010 (T. Owari) 13 Mean ± SD: 5.7 ± 4.0 m < 4 m in 20 points (47%) ≥ 10 m in 7 points (16%)

14. 2010/03/13 FORMATH2010 (T. Owari) 14 Mapping of Marked Trees N = 1,565 All positions were successfully measured

15. 2010/03/13 FORMATH2010 (T. Owari) 15 Comparison with the Conventional Map

16. Intersection with the Selection Stand 2010/03/13 FORMATH2010 (T. Owari) 16 n = 1,565 Within the selection cutting stand: 1,155 Outside of the selection cutting stand: 410 (26%)

17. Spatial Distribution of Harvest Intensity 2010/03/13 FORMATH2010 (T. Owari) 17 Mean density within selection cutting stand: 35.3 trees ha-1

18. Discussion Positional accuracy of the GPS receiver… … was acceptable for the use of tree marking … might be less accurate (>10 m) in some cases Mapping the location of marked trees… … provides the information on where trees were selected to be cut … helps improve efficiency of tree search (Takuma et al., 2009) Spatial analyses revealed that… … the marking decision was conducted in a flexible manner … harvest Intensity was not uniform throughout the stand 2010/03/13 FORMATH2010 (T. Owari) 18

19. Conclusions GPS is a useful tool for managers and loggers… To easily record the location of trees that were marked for harvest To provide the information on where marked trees are located To know exactly how tree marking operations are implemented Future topics: How can we improve the positional accuracy? How can we reduce the cost and effort for tree marking operations? How can we evaluate the impact of harvest on stand dynamics? 2010/03/13 FORMATH2010 (T. Owari) 19

20. Thank you! This study was partly supported by the Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), 20710035, 2008 – 2009 (Corresponding address: owari@uf.a.u-tokyo.ac.jp) 2010/03/13 FORMATH2010 (T. Owari) 20