Maple

Maple tree is one of the trees that are very familiar to us. They are well known for few things. The maple syrup we use is from the maple trees. Actually, the maple syrup comes from only few species like sugar maple tree out of 125 species. Maple trees also give us fantastic view in autumn as they change their colors. Maple tree's fruit, also known as 'maple key', is famous as it spins around like the blades of helicopter as it falls down. The maple tree is also the main symbol of Canada. The leaf of maple is center piece of the flag of Canada, and the maple tree is the arboreal emblem of Canada. Maple trees are recently having hard time to survive in a non-suitable place. They are suffering from 'maple decline', which have resulted from the development of industry. In order to prevent 'maple decline', the maple tree species should be planted in suitable places.

Anatomy
Maple trees usually range from 10 to 40 meters in height. Their leaf arrangement is opposite. The leaves are mostly palmately veined and usually have 3 to 5 pointed lobes. As an exception, few species have different types of leaves such as palmate compound, pinnate compound, pinnate veined or unlobed. Maple flowers usually spring during the late winter or early spring when the leaves start to appear in trees. The flowers are regular, pentamerous. They have five sepals, and five petals which are about 1 to 6 mm long. Maple flowers can be either green, yellow, orange or red. The fruit of maple is one of the distinctive parts of the maple. This distinctive fruit is called ‘samaras.’ In order to carry the seeds to quite far places, the fruit is designed to spin as it falls. 

Reproduction
The fruit of maple is one of the distinctive parts of maple. The maple fruit, known as 'samaras', is sometimes also called as 'maple key.' Those fruits have one small seed enclosed in each side of a nutlet, which is attached to thin, fibrous, paper like wings. When the fruits ripe, they fall to the ground with the wings spinning like the blades of helicopters, in order to carry the seeds to a far places. Usually in a few weeks to six months, seeds start to mature and start to bloom a flower. Most species will not sprout until the stratification is set, and some seeds can even just remain in the soil for several years. 

Ecology
Recently, maple trees are suffering lots of stresses, especially ones that are planted in urban areas. They are often planted in low-quality soils and are continuously exposed to salt and air pollution. These stresses result in smaller leaves, leaf browning and death of branches or limbs. This phenomenon is called 'maple decline.' It is not a disease, but rather a symptom that result from today’s bad environment. This 'maple decline' needs proper prevention or care to the maple trees. But since many problems are caused by combination of factors, it is not easy to categorize the reason. Not all tree problems can be controlled, but by suiting the maple tree species in proper places, most can be prevented. 

Symbolism
Maple leaf has been the main symbol of the National Flag of Canada, since 1965. Many Canadians wear maple leaf and pins proudly around the world. Of 13 species that are native to the North America, 10 of them grow in Canada including: Sugar, Black, Silver, Bigleaf, Red, Mountain, Striped, Douglas, Vine and the Manitoba. These maple trees have played a quite important role in the development of Canada and are still in their way to be commercial and aesthetical. Maple wood is one of the favored woods for flooring, furniture, interior woodwork, veneer, small woodenware. Maple trees also provide a fantastic view in autumn. Although maple trees have impacted Canadians in lots of ways, the maple tree was officially declared as Canada’s arboreal emblem in April 25,1996. 

Related References

 * Maple by multiple authors. Wikipedia.
 * The Maple tree Canadian Heritage.
 * Maple - Leaves Rosie Lerner. Purdue University.
 * Maple Tree Decline M.J. Walterscheidt. University of Rhode Island.
 * Maple facts Thatcher's Sugarhouse.
 * Acer (1ACRG){Overview} European and Mediterranean Plant protection Organization Global Database.
 * An Illustrated guide to Maples, by: Antoine Le Hardÿ De Beaulieu.
 * Maples of the World, by: D. M. van Gelderen, P. C. de Jong, and H. J. Oterdoom.