Trees with wide canopies are preferred by landscapers for areas that need extensive, even shading. They are also used to determine the state of an ecosystem by arborists, who look for even and healthy canopy coverage. A tree's canopy is defined by the outer reaches of its leaves. Some trees have specially adapted wide canopies to take advantage of certain conditions, while for others, it is more advantageous for the leaves to reach directly upwards. Many shade trees also have very dense canopies, blocking the majority of light to species that may be growing under them.
Numerous trees around the world are well known for having wide canopies. A classic example is trees in the banyan family, a type of tropical fig tree. Banyan trees are somewhat unique in that they grow by colonizing and ultimately strangling another tree. The largest tree in the world is estimated to be the Great Banyan in Howrah, kept in the Indian Botanic Garden. Banyan trees have served as traditional meeting places in many tropical areas, because the ground underneath them is relatively clear and shady.
Other trees that commonly have wide canopies include oak trees, which also grow very densely, providing darkly shaded areas at their bases. Many species of maple also have high growing wide canopies, making them excellent choices for landscaping along roads and other areas where clearance is needed. Maples also make striking landscaping choices because of the color changes their leaves undergo in the fall.
Many nut trees, such as walnuts and pecans, have wide canopies, although they tend to be lower to the ground and less suitable for areas where clear space under the tree is valued. In addition, they can be messy as they lose their nuts and leaves. The fantastical looking baobab tree, found in Africa, also has a wide canopy, and its bizarre appearance is quite distinctive. Baobab trees, like many others with wide canopies, provide a valuable habitat for animals that live under them, which might otherwise suffer from weather exposure.
Members of the poplar and ash families also tend to have wide canopies, and the distinctive rustling made by their leaves can be quite pleasant. Several of the trees in the poplar family also flower, and like maples, they change colors with the seasons. Care must be taken when planting poplars, because they have strong and destructive root systems. Therefore, they should not be situated too close to homes, swimming pools, and the like.