Andy Gillen, age 13, of Beaumont, Tex., for his question:

HOW MANY KINDS OF EUCALYPTUS ARE THERE?

Eucalyptus is the name of a tall, hardy, heavily leaved tree that at one time could be found only in Australia. During the past century the tree has been moved to other spots around the world and it has adapted very well to living conditions in Algeria, Egypt, India, South America and the Southern United Staten. There are more than 250 different kinds of the tree.

The eucalyptus is now thought of as almost a "native" by many Californians because so many of them have been planted. They are used for ornamental purposes and also as orchard windbreaks.

The eucalyptus is a fast growing tree. A young sapling can grow as much as 12 feet in a single year.

Among the popular types of eucalyptus are the blue gum, the jazrah tree, the manna gum and the stringy bark tree. Some of the trees can grow to be 300 feet tall.

The trees are often planted in malarial areas, where they help to draw water out of mosquito infested swamps.