Why do some trees lose their leaves and others do not?

Trees follow two broad strategies for dealing with harsh seasons. Deciduous trees shed all their leaves before winter or a dry season because broad, thin leaves would lose too much water and could be damaged by frost while providing little energy in low light. By dropping them, the tree conserves water and resources until conditions improve. Evergreen trees, such as pines and firs, instead keep needle-like leaves coated in wax and often containing antifreeze-like compounds, which lets them photosynthesise whenever conditions allow and avoids the cost of regrowing a full canopy each year. Each approach suits different climates: evergreens dominate cold or nutrient-poor regions, while deciduous trees thrive where growing seasons are warm and moist.