I did a drone flight over a forest plantation and got the DSM and DTM. Later, I was interested in calculating the height of the trees within a plot. For this, I did a subtraction between the DSM and DTM. However, when verifying the height of the trees in the CHM, these are not correct, because they vary with respect to what was reported in the field. ¿Does anyone know why this could be happening and how it can be solved?