Snow fences
Snow fences are installed along roads where winds blowing onto the roads reduce visibility by causing snow to drift. The fences improve visibility on the road in drifting snow by weakening the winds.
The main types of snow fences are blower snow fences, collector snow fences and traditional collector snow fences.
Their structures and the conditions under which they should be installed are given in The Highway Snowstorm Countermeasure Manual
http://www2.ceri.go.jp/fubuki_manual/
pdf/manual.eng.pdf
Snowbreak woods
Snowbreak woods are bands of trees planted along roads to mitigate snow drifts and poor visibility.
Needle-leaved evergreen trees are the main trees. When evergreen trees are planted at an appropriate density, their leaves and branches help to lower the speed of winds blowing over the road and to reduce the amount of snow particles drifting over the road, thus mitigating visibility reductions.
Due to the harsh environment of the site not seeds but seedlings are planted and grown.
Because the trees take time to grow, snowbreak woods take time to become effective.
But once these trees have grown to heights of between 9.8 m and 14.4 m, they mitigate visibility reductions and prevent drifting snow.
For details, consult
The Highway Snowstorm Countermeasure Manual
( http://www2.ceri.go.jp/fubuki_manual/
pdf/manual.eng.pdf )