COMPARATIVE ASSESSMENT OF THREE SMARTPHONE APPLICATION FOR MEASURING TREE HEIGHT IN ODUN FOREST RESERVE,KWARA STATE, NIGERIA.

This study investigates the reliability and efficiency of three smartphone applications Arboreal, Hypsometer and Smart Measure by comparing their performances against a traditional height-measurement instrument, the Haga altimeter, for estimating tree height in Odun Forest Reserve, Kwara State, Nigeria. Tree height is a fundamental parameter in forestry, influencing biomass estimation, forest structure analysis, carbon stock assessment and ecological modeling. Although conventional tools such as clinometers, laser rangefinders, and the Haga altimeter are known for their accuracy, they are often costly, time-consuming, and require specialized training. With advancements in mobile technology, smartphone-based applications are emerging as affordable and user-friendly alternatives. Using a randomised sampling technique, height data were collected from 230 trees across multiple plots, with each tree measured using the three mobile apps and the Haga altimeter as a reference. Statistical analyses including paired t-tests, Pearson correlation coefficients (r), Root Mean Square Error (RMSE), absolute and relative errors and percentage bias were employed to evaluate measurement discrepancies. The results revealed that Arboreal exhibited the highest level of accuracy, with a low RMSE of 0.29 meters, near-zero bias and a strong correlation (r = 0.98) with the reference measurements. Conversely, Hypsometer and Smart Measure consistently overestimated tree heights, demonstrating significant measurement biases and lower statistical agreement. These findings highlight the potential of smartphone applications in forestry, while underscoring the need for proper user training, calibration and software refinement. The study concludes that Arboreal is a viable alternative to traditional tools, whereas Hypsometer and Smart Measure require improvements in distance estimation and internal measurement algorithms. Further research is recommended to enhance the accuracy and field applicability of mobile-based measurement tools.