Periodical Literature. 187 



returns, though slowly, and even the lower vegetation is little in- 

 fluenced by the clearings. The re-establishment of the forest 

 progresses, of course, at varying rates on the different soils. 

 Where areas, formerly wooded, are now bare, the cause is not 

 found in the forest use, but in the extensive pasturing of sheep, 

 which was carried on in commons. Since pasture grounds have 

 become individual property and sheep herding has decreased, re- 

 turns of the forest progresses. 



Skogsvardsforeningens Tidskrift, March, April, 1908, pp. 93-199. 



Olsson-Seffer has made a careful study of 

 Ecology the factors influencing the vegetation of 



of sandy sea-shores in many parts of the world. 



Vegetation He has visited many regions in both Tem- 



on perate and Subtropical zones, regions vary- 



Sea-Shores. ing greatly in climatic and geological char- 



acters. Some of his conclusions may be of 

 interest to those engaged in the work of reclaiming sandy areas 

 near the sea. 



He states that the atmospheric conditions are the most im- 

 portant factors owing to their influence on transpiration. 

 Sandy vegetation differs from inland flora in being subject to 

 great fluctuation of diurnal temperatures, owing to easy radiation 

 of heat from the sandy surface. The large amount of heat ab- 

 sorbed by sand and reflected from its surface, the intensity of 

 illumination direct and reflected, and the exposure to winds have 

 been very important factors in modifying plants in these locali- 

 ties. Another factor is the intense salinity of the air near the 

 sea-shore. This factor is according to Olsson-Seffer of greater 

 importance than the salty character of the soil. In fact he states 

 that the strand flora is not halophytic. The reason for this is that 

 beach sands, although supposed to be thoroughly saturated with 

 salt, are in reality only salt where inundated. The saline char- 

 acter is found at the surface, but the sand of lower levels where 

 the roots extend is not salt, being kept fresh by a flow of fresh 

 water. Further inland where the salt spray condenses the salt is 

 either washed out by rain or remains at the surface. 



The amount and distribution of precipitation throughout the 

 year plays an important part in binding sands and aiding the 



