The study was carried out in the year 2013, in specific climatic conditions characteristic for the Forestry Direction Reghin, in the 2nd arrangement unity of the U.P. I Breaza, on 50 Sylvester pine trees. The monitoring experiment was conducted, while the programme IBM SPSS Statistics v. 20 was used for field data processing. Within the experimental areal, by the year 2013, the climatic conditions are characterized by the mean temperature of 9.82 ºC, mean humidity of 73.70%, and mean rainfall regimen of 6.81 mm. The mean parameters characteristic for tree development are: 11.94 m – mean diameter, 11.45 m - mean height, 0.96 - mean coefficient of slenderness. Our study emphasizes that the pine tree diameter and height a strong coefficient of correlation was identified, while between the pine trees coefficients of slenderness and diameters, resulted only a mean coefficient of correlation.