Assessing Precision in Conventional Field Measurements of Individual Tree Attributes

Forests

Michael A. Wulder¹  Joanne C. White¹  Mikko Vastaranta²  Markus Holopainen²  Ninni Saarinen²  Ville Luoma²  Juha Hyyppä³ 

[1] Canadian Forest Service (Pacific Forestry Centre), Natural Resources Canada, 506 West Burnside Road, Victoria, BC V8Z 1M5, Canada;Department of Forest Sciences, University of Helsinki, P.O.Box 27 (Latokartanonkaari 7), 00014 Helsinki, Finland;Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey, Geodeetinrinne 2, 04310 Masala, Finland;

关键词: precision;    accuracy;    diameter-at-breast-height;    dbh;    tree height;    forest mensuration;    clinometers;    calipers;    hypsometers;    forest inventory;   

DOI  :  10.3390/f8020038

来源: DOAJ

【 摘 要 】

Forest resource information has a hierarchical structure: individual tree attributes are summed at the plot level and then in turn, plot-level estimates are used to derive stand or large-area estimates of forest resources. Due to this hierarchy, it is imperative that individual tree attributes are measured with accuracy and precision. With the widespread use of different measurement tools, it is also important to understand the expected degree of precision associated with these measurements. The most prevalent tree attributes measured in the field are tree species, stem diameter-at-breast-height (dbh), and tree height. For dbh and height, the most commonly used measuring devices are calipers and clinometers, respectively. The aim of our study was to characterize the precision of individual tree dbh and height measurements in boreal forest conditions when using calipers and clinometers. The data consisted of 319 sample trees at a study area in Evo, southern Finland. The sample trees were measured independently by four trained mensurationists. The standard deviation in tree dbh and height measurements was 0.3 cm (1.5%) and 0.5 m (2.9%), respectively. Precision was also assessed by tree species and tree size classes; however, there were no statistically significant differences between the mensurationists for dbh or height measurements. Our study offers insights into the expected precision of tree dbh and height as measured with the most commonly used devices. These results are important when using sample plot data in forest inventory applications, especially now, at a time when new tree attribute measurement techniques based on remote sensing are being developed and compared to the conventional caliper and clinometer measurements.

【 授权许可】

Unknown