The term ‘Deciduous” means “shedding or losing foliage at the end of the growing season”. This means that in autumn, the leaves of deciduous trees will start falling until the tree is bare, and it will remain so until new leaves start to emerge in the spring. 

There are many reasons for selecting a deciduous specimen as opposed to an evergreen. The primary one is that if the tree is planted in an area where you wish to have summer shade and winter sun, then the habit that a deciduous tree has of shedding its leaves is perfect. So if you want shade over your outdoor entertaining area to protect you from the harsh summer sun, but in that same area you want the warmth of the winter sun to penetrate, then you must choose a deciduous specimen.