Why does biomass of a oak tree change during the year?

The biomass of an oak tree changes throughout the year primarily due to seasonal growth patterns and environmental factors. In spring and summer, the tree undergoes active growth, photosynthesis, and leaf production, leading to an increase in biomass. Conversely, in autumn and winter, the tree may lose leaves and enter a dormant state, resulting in a decrease in biomass. Additionally, factors such as water availability, temperature, and nutrient supply can further influence these seasonal changes.