SYLVICULTURE. 



Sylviculture as a discipline comprises the following themes: 



A. Ecological principles, facts and definitions. 



B. The genesis of the forest. 



C. The pedagogy of the forest. 



D. The sylvicultural forms. 



In the discussion of themes B, C, and D, a distinction is made 

 between the treatment of: 



1. High forests. 



2. Coppice forests. 



3. Coppice under standards forests. 



Paragraph II. Ecological factors and their influence on the sylva. 



A. Definition. — Plant ecology is a branch of botany showing the 

 dependence and adaptation of plant forms and plant life of and to 

 the surrounding local factors (climate, soil, etc.). 



B. Natural laws govern the organization of the species and regu- 

 late the communal life (symbiosis) and messmateship (commen- 

 salism) of individuals with their own kin, with relatives and with 

 other plants belonging to the same household and feeding at tlie 

 same table. 



C. The most important ecological factors are: 



I. Air. Oxygen, nitrogen and carbonic acid, the main com- 

 ponents of air, are essential for plant life. The relative proportion 

 of the two integral parts, 79% N., 21% 0., varies very little with 

 altitude, latitude and elevation. Salt particles in the air near ocean 

 and sulphuric acid in the air near melting works are very injurious 

 to plant life. 



II. Light. Intensity depends on: 



Season. 



Latitude. 



Altitude. 

 Direct insolation is said to be on the whole of less importance 

 than diffused light (excepting polar regions). 



Light is not required for germination of seeds. Without light, 

 however, there is no assimilation, and hence no possibility of tree 

 life. Assimilation increases with increasing intensity of insolation; 

 excessive insolation is, however, destructive. For each species, and 

 for each stage of its growth, there exists a certain optimum, mini- 

 mum and maximum of insolation with reference to the possibilities 

 of its success. The damaging influence of excessive insolation is 

 prevented by the inner organization of the plant. 



