THE FOREST IN WINTER. 
213 
of these cases and the cover in the other. Little of the winter 
precipitation, therefore, is lost by evaporation, and as it slowly 
melts at bottom it is absorbed by the earth, and but a very 
small quantity of water runs off from the surface. The im¬ 
mense importance of the forest, as a reservoir of this stock of 
moisture, becomes apparent, when we consider that a large 
proportion of the summer rain either flows into the valleys 
and the rivers, because it falls faster than the ground can 
imbibe it; or, if absorbed by the warm superficial strata, is 
evaporated from them without sinking deep enough to reach 
wells and springs, which, of course, depend very much on 
winter rains and snows for their entire supply. This observa¬ 
tion, though specially true of cleared and cultivated grounds, 
is not wholly inapplicable to the forest, particularly when, as 
is too often the case in Europe, the underwood and the decay¬ 
ing leaves are removed. 
The general effect of the forest in cold climates is to assim¬ 
ilate the winter state of the ground to that of wooded regions 
under softer skies ; and it is a circumstance well worth noting, 
that in Southern Europe, where nature has denied to the earth 
a warm winter-garment of flocculent snow, she has, by one of 
those compensations in which her empire is so rich, clothed 
the hillsides with umbrella pines, ilexes, cork oaks, and other 
trees of persistent foliage, whose evergreen leaves afford to 
the soil a protection analogous to that which it derives from 
snow in more northern climates. 
The water imbibed by the soil in winter sinks until it 
meets a more or less impermeable, or a saturated stratum, and 
then, by unseen conduits, slowly finds its way to the channels 
of springs, or oozes out of the ground in drops which unite in 
rills, and so all is conveyed to the larger streams, and by them 
finally to the sea. The water, in percolating through the vege¬ 
table and mineral layers, acquires their temperature, and is 
chemically affected by their action, but it carries very little 
matter in mechanical suspension. 
The process I have described is a slow one, and the supply 
of moisture derived from the snow, augmented by the rains of 
