60 PRACTICAL FORESTRY 
ground is level, and the soil porous, there is, of 
course, little danger from floods. 
In this connection we are especially concerned 
with the part played by the surface cover. We are 
also concerned with the collecting area, rather than 
the stream-bed, because the principal mass of water 
forms in the former. Here erosion also begins, im- 
perceptible at first, but soon resulting in an immense 
volume of water, descending on all sides into the 
channel course, and collecting in its rush rocks and 
débris of all kinds. This powerful mass, by under- 
mining the banks, receives constant additions, until 
the whole is dumped into the level plain, where the 
torrent emerges with diminished force. A torrent to 
be conquered must be attacked where its forces are 
seattered and easily controlled. The place to conquer 
it is in the hills of its source. The way to conquer it 
is through the agency of forest-growth. 
The flow of water is retarded by roots and litter 
of the forest-floor. Instead of rushing quickly ito 
large branches forming deep gulches and gorges, it 
seeps into the soft forest soil and appears later in the 
form of springs. Much of it trickles by circuitous 
routes into larger branches, being impeded on every 
hand by the forest débris. When the collecting area 
is covered with a dense forest-growth, the water 
which falls is therefore much more evenly distributed 
