489 



PROTECTION AGAINST ATMOSPHERIC 

 INFLUENCES. 



FORESTS from the seedling stage up to maturity are subject 

 to the influence of the weather, and may thus be injured in 

 various ways. The chief meteorological phenomena in question 

 are frost, heat, wind (especially storms), heavy rainfall, hail, 

 snow, rime and ice. 



As a matter of course, these phenomena frequently act 

 beneficially on vegetation ; frost disintegrates the soil and 

 prepares it for the reception of seed and the growth of forest- 

 plants ; the wind disseminates the seed gof many trees and 

 shakes snow from off their crowns which might otherwise be 

 broken by its accumulating weight ; atmospheric precipitation 

 and heat are indispensable for vegetable growth ; snow is a bad 

 conductor of heat, it keeps the soil comparatively warm in 

 winter, and protects young plants from frost. Snow also 

 absorbs much air and with it carbon dioxide ; the decomposi- 

 tion of mineral matter on which the formation of soil chiefly 

 depends is expedited by carbon dioxide, so that winters with 

 heavy snowfall are highly advantageous in this respect. 



Forest Protection has, however, less to do with the beneficial 

 action of these phenomena than with the damage they may 

 inflict on forest plants, and the means acquired by experience 

 for protecting them. 



The amount of damage done is conditional on several 

 circumstances. In the first rank are the extent and intensity 

 of the phenomenon, but the season and the state of the 

 weather before, during and after the calamity are also of 

 importance. 



In the second place, the nature of the wood and locality 

 should be considered ; of great importance are the species of 

 tree grown, the system of management of the forest, and the 

 age and density of the injured woods, as different species and 

 age-classes suffer in different degrees from bad weather. As 



