Susan Darlene Toomey, age 11, of St. Catharines, Ontario, Canada, for her question:

Which tree produces hardwood?

The leafy maple that belongs to Canada gives us handsome hardwood. The wood of the sugar maple is even harder, perhaps because it grows very slowly and lives to a very great age. But the numerous maples are not the only hardwood tree. This list is longer than your arm. It includes the oaks, beeches and birches that mingle with the evergreen conifers in temperate and northern forests. It includes many fruit trees, walnuts and a variety of other nut trees.

In the temperate and northern zones, most of the broad leaved trees that lose their leaves in winter are called hardwood trees. The knotty pines and other ever¬greens that bear needle shaped leaves are classed as softwood trees. In the tropics, however, even the trees with huge wide leaves stay green through the year. These tropical evergreens include mahogany and a long list of other glamorous hardwood trees.