There are many different kinds of trees in the world. Different types of trees grow in different parts of the world. For a tree to grow in a certain climate it must have the ideal characteristics to grow in certain climates. For instance, a tree growing in a part of Costa Rica, (in Central America), where it is hot and rainy has different characteristics than a tree growing in a very cold part of the world, like Alaska. There are also trees that grow in moderate temperatures and are well adapted to grow in areas like Ohio in the United States.


For a tree to grow well in an area like the rainforest of Costa Rica it must fit in well with its tropical rainforest surroundings. In tropical rainforests, the forest is very dense and some trees are very tall, about 33 meters in height. For a tree to get maximum sunlight it must be very tall and have a very wide crown. The canopy is the top layer of the forest formed by the branches and leaves of many trees. However, other trees successfully make their home in the "understory" far below the towering height of the canopy. These understory trees are about 8 meters high and have crowns that are somewhat round. They live by gathering filtered sunlight, or sunflecks, seeping through openings in the canopy. A rounded crown and a height of about 8 meters seems to be ideal for collecting these filtered rays of sun. The most common type of leaf found in this area is a broad leaf. These leaves are sometimes thinner than those leaves in a temperate zone because there is enough moisture in the air that the leaves do not need to retain as much water.


In coniferous forests of the north, trees must be shaped in a way that captures the sun's rays -- even though the sunlight is not coming directly from above. Unlike tropical rainforests in which sunlight is directly above around noon, in Fairbanks, Alaska the sun never rises above 47 degrees in the sky. To absorb light comming in from a low angle, trees in Alaska tend to have a deep, steeply sloping crown -- thus the familiar shape of a Christmas tree! They are cone shaped, big at the bottom and skinny on top, and grow over 30 meters tall. This way, sunlight can shine on the tree from lower angles. Long, thin needles capture sunlight and through photosynthesis turn it into energy and food for the tree all year long. These needles retain moisture better than broad leaves, which is a major advantage in a cold, dry climate. While some trees are taller than others, there is little advantage to being small. For this reason, the coniferous forests of the north lack the understory of southern deciduous forests.


Temperate forests are located in climates with moderate temperatures that are neither very hot nor very cold. The temperate forest is less dense than the rainforest, with the tallest trees over 30 meters in height. For a tree to get maximum sunlight it must be tall and have a wide crown. The canopy is the top layer of the forest formed by the branches and leaves of many trees. As in the rainforest, other trees successfully make their home in the "understory" far below the canopy. These understory trees, such as the Eastern Redbud, are about 8 meters high have a somewhat rounded crown. They live by gathering filtered sunlight, or sunflecks, seeping through openings in the canopy. A height of about 8 meters, and a rounded crown, seems to be ideal for collecting these filtered rays of sun. The most abundant type of leaf in the temperate forests is the broad leaf. These leaves are wider and capture more sunlight than the needles of coniforous trees, making them well suited to regions with moderate rainfall.

Having learned a bit about the shapes of trees, click on the underlined words when you are ready to play a tree shape game.