Growth and defoliation are important indicators of tree vitality. To better elucidate the problem of holm oak defoliation, we examined the relationship between stand dendrometric parameters and defoliation on six plots in the Chettaba forest (northeastern Algeria). The dendrometric parameters calculated according to the plots vary from one plot to another. Thus, the density varies from 200 to 987 individuals / ha, the average diameter from 9.52 to 18.14 cm, the average height from 3.79 to 5.85 m and the basal area from 0.13 to 8.53 m²/ha. Descriptive data show that 40.57% of the inventoried trees had low defoliation and 44.16% are heavily defoliated and dying. The analysis of variance shows a correlation between defoliation and dendrometric parameters, a significant difference is recorded for the total stand density. The defoliation rate tends to increase when the stationary fertility increases and vice versa due to the competition between trees especially in relation to water resources. Therefore, a specific management plan for the regulation of competition is a necessity for this forest.