&2 FORESTRY IN SPAIN. 



forcstral, meteorological, and other cognate subjects, by 

 Senor Don "Rafael Alvarez Sereix, member of the Corps of 

 Forest Engineers, an eleve of the School of Forestry, and now 

 Director-General of Geography and Statistics in Madrid, 

 which have appeared in Spanish periodicals, and been 

 re-publshed in two series, entitled Estudios Botanico- 

 F or estates ; and others* which have been published in a 

 volume entitled Cuestiones Cientificas, copies of which 

 are at the command of the students. 



One of the papers published by Senor Alvarez, under 

 the title of Estudios Botanico-Forestales, is entitled 'The 

 Influence of Forests on Climate,' based on the valuable 

 treatise on the subject by M. A. C. Becquerel. In this the 

 term rendered forest is used as one applicable to a con- 

 siderable extent of country covered with a spontaneous 

 growth of an arborescent vegetation. And following 

 Humboldt, the author says the climate of a country is the 

 result of the calorific, aqueous, aerial, luminous, and electric 

 phenomena, which may cause one determinate locality to 

 present a different meteorological character from another 

 of the same latitude and geological conditions. 



Assuming that of the influences specified heat exercises 

 the greatest influence, and next to this the quantity of the 

 rainfall in the different seasons of the year, and next to these 

 the humidity or aridity of the air, the predominating winds, 

 the number and distribution of storms in the course of the 

 year, the degree in which the heavens are clouded, the 

 nature of the ground, and of the vegetation covering it, 

 and whether this be spontaneous, or the result of culture, 

 Senor Alvarez proceeds to discuss the questions which will 

 determine what is the effect of woodlands on the climate 

 of a country, which questions he assumes to be these : 



1. In what degree do the forests act as a protection 

 against the winds, and in what measure do they retard the 

 evaporation of the water of the rainfall ? 



2. How do they modify the hydrometric condition of 

 the surrounding atmosphere by absorption by roots, and 

 by evaporation from leaves? 



