Ann Flesher, age 11, of Lansing, Mich., for her question:

WHY DOES MOSS ONLY GROW ON THE NORTH SIDE OF TREES?

Some people claim this is true. When they get lost in the woods, they search for a mossy tree trunk, feeling sure that these velvety little plants grow only on the north side. Sad to say, the mosses may grow on any or all sides of a tree. If we trust them to point the way home, they may lead us deeper into the woods.

When hiking in strange woods, be sure to carry a compass and a mirror  and keep notes about the path as you go. Just in case you do get lost, most likely the notes and compass can help you retrace your steps. If these fail you, then make yourself comfortable while you wait for the rescue squad. Holler or blow a whistle from time to time  and if a helicopter goes by, use a sunbeam to flash a signal from your little mirror.

But do not depend on the mosses to point the direction. Some of them, perhaps most of them, may be clinging to the north sides of the tree trunks.    But you cannot be sure. True, the north side is the shady side, and this fact can help you. However, you would have to understand how the sun's position in the sky can reveal time and directions here on the earth  which is quite complicated.

There are thousands of different mossy plants, and each species has its own lifestyle. All of them have tender greenery that soak up moisture with dissolved chemicals. For this reason, most of them do better in moist, shady spots where the dew and the raindrops tend to linger. These types are very much at home in the damp, shady woods. Many of them prefer the north side of the trees, where they are shaded all through the day.

However, a few hardy mosses can get along with less moisture and less shade. They can grow on all sides of a tree trunk or even right out in the sunshine. Besides, when the trees in a woods are crowded close, they cast deep shadows in all directions. The whole area is shaded all through the day  so even the moisture loving mosses can thrive on all sides of a tree.

    Every summer, hundreds of young explorers get lost in the woods.     Those who follow the sensible rules and wait for the rangers most likely get home before dark.  Those who trust the mosses or try to guess the right direction are likely to stay lost for days and days. And this is a ghastly     experience.