Laser Caliper Reliability in Upper-Stem Diameter Measurements by Multiple Users

Considering the uncertainty of upper-stem diameter measurements and fact that there are few studies on accuracy diameters using Mantax Black caliper with Gator Eyes (Haglöf, Långsele, Sweden), aim this research is to check laser reliability in measurements. The study was conducted Parc Aventura Braşov (Romania), where a target tree marked visible signs at 1 m, 3 5 7 9 13 m above ground, six sections were measured conventional climbing equipment. Later on, 14 forest mensurationists used measure away from tree, maintaining direction measurement. Each user performed repeated independent diameters, resulting data sets 10 values for every section total number 840 observations. Applying ANOVA all sections, we found significant differences between collected by many users, pairwise t-test Benjamini-Hochberg method showed differences. Taking into account analysis individual errors measuring caliper, able identify affected abnormal errors. By along stem up ground one out 2.4 approximately 1.5 determined an error below 2 cm. At heights maximum five 4 In addition, it noted generally tendency underestimate volume estimate when absolute mean varied 1.46 cm 2.52 root squared 1.84 3.04 Nevertheless, general about subject remains, because if without contact trunk, will never know whether single reading shows negligible be calibrating taper equations or increasing estimation accuracy. Consequently, recommend purpose, should several times, experienced users who have proven their skill yield smaller