HOW THE 
WORK IS DONE 
The whole idea is to stop the snow at the 
top of the steep slopes from starting to slide. 
As high up as it is possible to grow trees— 
and of course many of the worst areas for 
avalanches are above timber line—depend- 
ence is placed on a forest cover treated as 
protection forest. Above the forest the meth- 
od is to build barriers, masonry walls, that 
shall hold the snow in place or actually stop 
small slides, on the same principle that the 
points inserted between the tiles of a roof 
keep the snow from sliding off into the street. 
At Chamonix, France, at the very top of 
the slope there are also being constructed 
snow fences, made of cross planks held in 
place by steel bars set in the rock. After the 
manner of snow breaks along railroads, these 
barriers prevent drifting to some extent. At 
any rate they help to fix and hold the snow 
at the particular point where the avalanches 
are most liable to start. 
As all the material used in construction has 
to be packed up from the valley, often on 
men’s backs, the costs of this work are high. 
Even with wall building the figures are large, 
for it is hard to hold laborers in the face of 
the cutting winds, the fogs and the cold that 
even in summer are of frequent occurrence at 
these high altitudes. But in the aggregate 
a great deal of avalanche control work has 
been done both in France and in Switzerland, 
with beneficial results to the valleys below. 
There is some danger from avalanches that 
start from the breaking off of great boulders 
from the almost perpendicular walls of the 
“needles”, or sharp peaks, along the ridges 
of the divides. In many instances it is im- 
practicable to do anything of value to avert 
damage from this particular source. But 
again there are places where the cliff can be 
shored up, as it were, or where a great boul- 
der that has lodged a little way down the 
slope can be held in position by the building 
in of a foundation, or retaining wall, on the 
lower side. Above the timber-line use is 
made of hardy shrubs and of grasses, which 
started in clumps and lines, spread over the 
surfaces of bare soil and so prevent erosion 
by washing. 
Another type of avalanche is that caused 
by “land-slips’”. In this case the upper strata 
becoming super-satured with moisture, may if 
they lie over a clay substratum simply slide 
off in large blocks in continued wet weather, 
and especially in connection with the action 
of frost. A particularly good example of this 
sort of thing occurs at Murren, a mountain 
village above Lauterbrunnen in Switzerland. 
Above that little town the mountain wall rises 
almost as a precipice for something like 2,000 
feet. Above this the slope is moderate but 
steady. Above the cliffs are strata of clay 
that underlie the surface soil. If a slide 
started it would go over the cliff and fall on 
a part of Lauterbrunnen. The remedial meas- 
ures that have been taken consist of large 
strong retaining walls, supplemented by small 
barrages of stone and wicker work to stop ero- 
sion on the surface, and of the replanting with 
forest of open areas where trouble might 
start from snow slides. 
The forester, if he be wise, adopts meas- 
ures in all that he does that permit him to 
work with, rather than contrary to nature. 
Even when it comes to combating natural 
forces he still does well to rely on living 
things as well as on artificial helps, such as 
walls and dams. Naturally all this leads to 
a variety of methods, for what is effective in 
one locality may not be at all what is re- 
quired in another place. Reboisement is a 
task that calls for ingenuity and persever- 
ance. That is what gives to this work its 
peculiar fascination. 
As never before the protective role of the 
forest is today being recognized. The indi- 
FIRE LINE 
IN THE 
MARITIME 
PINE FOREST, 
LACANAU- 
OCEAN, FRANCE. 
THESE FORESTS 
ARE 
PARTICULARLY ° 
SUSCEPTIBLE 
TO FIRE 
(59) 
