PERIODICAL LITERATURE 757 



Bernbeck discusses the adaptation of vegeta- 

 Vegctation t:cn to wind and the efifects of wind on vegeta- 



as Affected tion, with especial reference to forest growth. 



h\ Wind Adaptation is to enable the plant to withstand 



the physical impact of wind, or to prevent ex- 

 cessive evaporation from the plant tissues or both. Wind firmness is not 

 an inherent characteristic of any given species, although the tendency to- 

 ward windfirmness may be inherited ; thus a fir grown in the open may 

 be much more windfirm than an oak grown in a dense stand protected 

 from wind. Under the right conditions any tree can develop a windfirm 

 form. This fact can be utilized in silvicultural management, so as to 

 minimize loss from windfall. (35,000,000 cubic metres of timber, 

 principally coniferous, was blown down in Germany during the last 

 century.) Wind climate often governs the geographical distribution 

 of trees. For instance, conifers are most liable to injury during the 

 winter months, so sites exposed to continuous winter storms (if fertile 

 enough to allow tall tree growth) are usually occupied by hardwoods, 

 while mountain slopes and plateaus wdiere heavy early summer winds 

 prevail are occupied by conifers. Wind affects the growth and form 

 of trees not only indirectly, by its influence on such site-factors as 

 soil moisture, transpiration, temperature, and exposure of foliage to 

 the light, but also directly, by its physical effect on the plant tissues. 

 Internal stresses and friction between the fibres result in eccentric 

 growth, and also help to stunt the tree by interrupting sap-flow and 

 through their effect on cell structure and turgescence. Investigations 

 made at Bonn showed clearly that the stunting effect of wind increases 

 rapidly with wind velocity. W. N. S. 



Bernbeck. Das Wachstum im Winde. Forstwiss. Centralbl. 42 :27-40, 59-69, 

 93-100, 1020. 



There is a close relation between soil composi- 



Smoke Injury tion and quality and the damage which may re- 



and suit to vegetation from various fumes and dusts. 



Soil Science Most smoke damage is done indirectly, through 



effect of the chemicals on the soil and humus. 



Lime is especially necessary in soils exposed to acid fumes, and should 



be added in the cheapest way possible where soils are poor in lime, 



otherwise the acids will remove all the lime present. This applies 



both to open and to forest lands. It has been computed that in the 



vicinity of vSotlbcrg f Rhine province) approximately 800 grams of 



