Why don’t all trees lose their leaves?
It really depends on the climate in which the trees are living. In areas like tropical rainforests – which are warm and moist – there is moisture available all year round. This moisture allows trees to keep their leaves year round.
Also, trees known as Conifers can keep their leaves year round as well because the leaves of Conifer trees are more like narrow needles. Because their leaves are narrow they do not lose moisture as quickly as the broader leaves, which means that Conifers often keep their leaves through the Winter even if there is a water shortage.