ABSTRACT Buttresses and other natural structures modify the shape of stems in Amazonia and change the diameter at breast height (DBH) measured at 1.3 m at ground level. The lack of adequate measurement techniques affects negatively forest dynamics analyses and biomass estimating. The study evaluated an indirect method of measuring diameters in trees with DBH > 40 cm using principles of digital photogrammetry. The results obtained with two cameras (smartphone and Sony) were compared with direct measurements using diametric tape and a ladder. The technique is adequate to measure the diameters of trees with measurement point above 2 m of ground, with a confidence interval of ±1cm. The use of photogrammetry as a supplementary tool to the diametric tape (IC ± 0.24 cm) is recommended, helping to measure trees with diameter above the reach of the technician in forest inventories.