Mark Ghimshaw, age 12, of Peoria, I11., for his question:
WHAT SORT OF ROOTS DOES A REDWOOD HAVE?
Some of California's redwoods stand more than 300 feet tall and they have stood there, firm and steady, through 2,000 years. One would expect such forest giants to be supported by enormously deep root systems, perhaps reaching halfway down to the People's Republic of China. But this is not so.
A tree, as we know, needs a root system to absorb water from the ground and also to act as an anchor when the wild winds blow.
As a general rule, its roots spread as wide as its branches and often reach as far down into the ground as its trunk reaches up into the air. If a giant redwood followed the same general plan, its roots would not spread very far, but they would reach down perhaps 300 feet. Instead, the redwood root system is rather shallow but often it spreads through several acres, just below the surface.
A root system of this kind is fine for absorbing the surface moisture that constantly drips from the foggy boughs. But it does not do much to anchor the giant trees when the wild winds blow. This helps to explain why we seldom find a solitary redwood. Almost always the big trees grow together in crowded groves.
Under these conditions, their shallow spreading root systems have an advantage. Below the surface, the intertwining roots of many trees form a community structure that helps to support the entire grove. This works well when the giant trunks are close together. For above the surface they baffle the winds which also helps to protect the entire grove.
However, though the trees in the center of the grove are protected by their close neighbors, those around the edges are not so lucky. At least part of their root systems are all alone and exposed just below the surface. They have less protection from the tangled roots of their neighbors. Often these forest giants are felled by winter gales.
Centuries agog the foggy slopes of the coastal mountains were crowded with redwoods for miles and miles. Gradually vast areas were logged for lumber, and roads were cut through the forests. This left many of the giants standing around the edges, partly exposed to the weather. Their chances of survival are reduced, and often they fall.