The rate, or speed, at which trees grow is dependent on multiple factors. The most important of these include genetics, soil, drainage, water, fertility, light, but there are many more as well.

This is a difficult question to answer because the growth rate of any plant depends on site conditions and maintenance. In most cases, the growth rate given for a particular plant is based on optimal conditions.

Trees do not grow like the human body, they grow by producing new cells in a very limited number of places called meristems, where cell division takes place.

The following is a nice and interesting site where you can learn how a tree grows.

Trees grow out and down, and depending on the type of tree and the optimal conditions, they will take different times to grow.