Trees are among the most resilient and adaptable organisms in the face of harsh environmental changes. They stand tall for years, even centuries, despite exposure to environmental stressors such as drought, salinity, climate change, and pollution. Trees have developed a set of physiological and morphological mechanisms that help them adapt to difficult conditions, making them a living model of environmental resilience.<br /><br />First: Environmental Stress and Its Effect on Trees<br />Environmental stress refers to those unfavorable factors that affect plant growth and disrupt their vital processes. These factors include high or low temperatures, water shortages or excess water, salinity, nutrient deficiencies, and exposure to pollutants.<br /><br />When trees are exposed to these conditions, processes such as photosynthesis, respiration, and water absorption are affected, which can lead to a decline in growth or even tissue death in severe cases.<br /><br />Second: Mechanisms for Tree Adaptation to Stress<br />Modifying Leaf Shape: Some trees reduce the size of their leaves or coat them with a waxy layer to reduce water loss through evaporation, as is the case with olive and pine trees.<br /><br />Deep Root System: Some trees, such as neem and acacia, develop deep roots that reach distant groundwater sources, enabling them to survive long periods of drought.<br /><br />Stomata Closure: During drought, trees close the stomata on their leaves to reduce water loss, but at the same time, they reduce carbon dioxide entry, which affects photosynthesis.<br /><br />Production of Protective Compounds: Some trees secrete chemical compounds such as protective proteins and soluble sugars that help cells withstand extreme salinity or cold.<br /><br />Seasonal Leaf Loss: Some trees shed their leaves during dry seasons to conserve water, a common strategy among deciduous trees.<br /><br />Third: The Importance of Studying Tree Adaptations<br />Understanding how trees adapt to environmental stress not only contributes to forest conservation, but also helps develop sustainable agriculture, improve fruit tree varieties, and select suitable plants for afforestation in desert or degraded environments.<br /><br />Al-Mustaqbal University is the first university in Iraq.