In this work, the riparian area in the cerrado presentin five streams belonging to the micro urbanized basin of the municipality of Gurupi -TO, was studied with the following objectives: to adjust mathematical functions (logarithmic, exponential, hyperbolic, linear and nonlinear) to determine probability density functions because they are used as a signature of ecological processes that occur in forests, as well as to determine floristic similarity. The results expressed by the frequency graphs, the formation of the inverted J, with a small disturbance between the initial diametric classes and intermediates, indicating the presence of anthropic actions. The functions were selected by the values of R²aj, Syx%, graphical analysis of the residues and F value, which are: y=exp(25,581+(-60.611)/x+(-6,184)*ln(x)) for Água Franca, y=x/(0.639+-0.084*x+0.004*x 2)for Two Brothers, y=124.243*exp(((ln(x)-2,559)^2/(-0.379)) for Mutuca, y=1/(0.0001*(x+(-15,250))^2+0.020) for Medium I Landing and y=(0.497+0.313*x)/(1+(-0.121)*x+0.004*x^2 ) for Medium Landing II. The FDP's selected for DAP's estimates are accurate and can be used in other areas of the same plant typology. There is floristic dissimilarity between streams and also within streams.