Accuracy of mobile forest inventory application KatamTM Forest : evaluation of accuracy in different forest types and comparison to conventional inventory methods

Abstract: In recent decades with the advancement in technology, novel forest inventory techniques for quicker and cost-efficient results have been developed. A Swedish start-up company has developed an application for smart phones called KatamTM Forest which can do a forest inventory by recording videos in the stand. Even though, more forest inventory methods are accessible, conventional methods are still widely preferred because of the accuracy. This thesis aims to test the accuracy of Katam mobile application on single tree and stand level in different types of forest by comparing it to conventional inventory methods. Six Norway spruce production stands of varying ages and four heterogenous habitat protection stands were included in this thesis. Katam provides an easy way to quickly capture a large part of the stand, thus raising the efficiency and percentage of the stand covered comparing to conventional inventory methods. The application seems to miss smaller trees and was therefore significantly overestimating the mean diameter at breast height in conservation stands. The RMSE for dbh on single tree level was 2.9 cm in production stands and 6.9 cm in habitat protection stands. No statistically significant difference was found between inventory methods when comparing basal area (m2 ha-1), volume (m3 ha-1) or density (stems ha-1) in either of the two types of stands. Novel technologies provide an easy and accessible way to conduct a forest inventory and with the further advancement in technology and research are likely to make conventional methods obsolete in the near future. Currently, more development and calibration might be needed to fully start using Katam in mixed heterogenous stands which are not necessarily meant for production.