Journal of The Japan Forest Engineering Society
Online ISSN : 2189-6658
Print ISSN : 1342-3134
ISSN-L : 1342-3134
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Displaying 1-3 of 3 articles from this issue
ARTICLE
  • Yohei Matsuzaki, Yosuke Kondo, Yasuyuki Kishi, Jun Esumi, Ryohei Tatew ...
    Article type: research-article
    2022 Volume 37 Issue 3 Article ID: 37.141
    Published: July 31, 2022
    Released on J-STAGE: August 16, 2022
    JOURNAL OPEN ACCESS

    Accurate location information in forest environments is a crucial requirement for achieving information and communication technology (ICT)-based forestry, and improving its accuracy is currently one of the key objectives. In this study, a closed traverse survey in a seedling stand was conducted using an RTK surveying technique with a low-cost dual-frequency GNSS receiver and high precision positioning service provided by SoftBank Corporation. The precision and accuracy levels in our results were subsequently compared with those obtained by the autonomous positioning and post-processed correction using a mapping-level GNSS receiver. ANOVA results showed significant precision errors in the measurement methods and survey points, while significant accuracy errors in the measurement methods and period of measurements were observed. Notably, the low-cost dual-frequency GNSS receiver generated smaller errors than the mapping-level GNSS receiver. Our results also suggest the potential accuracy of RTK measurements even with shorter surveying period due to the small positional errors detected in both their precision and accuracy. The area calculated by the coordinates obtained with RTK measurements was found to be between -0.2 and -0.1% short of the true area. In conclusion, RTK readings taken with the low-cost dual-frequency GNSS receiver showed extreme efficiency for both point positioning and area measurements in the closed traverse survey.

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RESEARCH AND TECHNICAL REPORT
  • Masahiko Nakazawa, Tatsuya Sasaki, Chikashi Yoshida, Takumi Uemura, Hi ...
    Article type: rapid-communication
    2022 Volume 37 Issue 3 Article ID: 37.149
    Published: July 31, 2022
    Released on J-STAGE: August 16, 2022
    JOURNAL OPEN ACCESS
  • Masaru Watanabe, Masashi Saito, Kenichiro Toda, Hiroaki Shirasawa, Tat ...
    Article type: rapid-communication
    2022 Volume 37 Issue 3 Article ID: 37.155
    Published: July 31, 2022
    Released on J-STAGE: August 16, 2022
    JOURNAL OPEN ACCESS

    The following results were obtained from the forest road registers for privately-owned forest roads in Nagano Prefecture. Approximately 36% of the totaled routes (n = 1504) experienced no forest road facility disasters. The standard deviation of the distribution of restoration cost per affected area was 260,024,000 yen, and the distribution varied by age class. The total restoration cost analysis each year shows that 50% of the whole damage was caused by a little over 10% of the total number of damaged routes. The mean, median, and standard deviation of the restoration unit cost were 222 yen/year・m, 55 yen/year・m, and 436 yen/year・m, respectively. The restoration unit cost was <100 yen/year・m for about 59% of the total routes and <1000 yen/year・m for about 95% of the total routes, resembling a stable distribution with a heavy right hem. No clear proportional relationship was found between the number of years since opening and the restoration unit cost. The median restoration unit cost by standard was 185 yen/year・m, 71 yen/year・m, and 37 yen/year・m for Class 1, Class 2, and Class 3 forest roads, respectively. The residual standard deviation between the estimated and actual restoration unit costs calculated using the existing method is 464 yen/year・m.

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