Tolerance Holm oak trees (Quercus ilex L.) to seasonal climate variations and fire are related to changes in the morphological, biochemical and ecophysiological complex. This tolerance has been characterized in natural conditions (forest of Chettabah, East-Algeria). A biochemical approach for such jointly measures the accumulation of solutes (soluble sugars and total proteins) in different organs during the four seasons of the year in two different stations (fire and non-fire). Significant variations of these accumulations are observed. The different buildup of these metabolites varied depending on the body and the degree of stress, the accumulation of sugars and proteins is highest in leaves during the spring and summer seasons and the levels of these metabolites is the same in both stations. These changes in markers show that Holm oak has a capacity to adapt to thermal variability and fire in forest of Chettabah