Applications and smartphones for measuring the height of trees in planted forest

Abstract

The present work had as objective to evaluate the accuracy of applications, smartphones and measurers in inferring the total height in a planted forest. Thirty trees were randomly selected, measured in a Tectona grandis stand, by three applications (Measure height, Two point height and Hypsometer), three smartphones (Samsung Galaxy S8, S6 and J7) and three measurers. The trees were logged and their real heights were obtained with a tape measure. To assess accuracy, a t-test for independent samples was performed, after verification of homogeneity of variances by Bartlett's test and normality by the Shapiro-Wilk test, all at 95% confidence levels. In addition, graphical analysis of residues was performed, as well as complementary statistics (bias, mean of absolute differences, standard deviation of differences and root of mean square error). We concluded that depending on the application used, there are smartphones that are not indicate for height measurement. The best-performing application is the Hypsometer. Galaxy S6 smartphone presented the best estimate, preferably for the Two point height application. The measurer experience was confirmed as essential requirement in height estimation using applications and smartphones.