The main focus of this thesis is to determine the correlation between various growth quantities and quality and quantity of biomass grown on plantations of fast-growing trees and the size and abundance of stomata. The measurements were done on different clones of fast-growing poplars, namely P463 (MAX1), P467, and P739. Clones were located in the clone archive in Budča. In this thesis, various quantities were evaluated: height, diameter in 10 and 130 centimeters above ground, heat value, and ash content. Correlation between abundance and also size of stomata and growth quantities was found. Correlation between abundance and also size of stomata and heat value was not found. A negative correlation between abundance and also size of stomata was found in the tested samples.