izO PKEJJMINAKY WOKKS. 



ninst decide whicli shall be i^rown, or wlietluM- <i iiiix('(l wood 

 is preferable. 



Owing to the great variety of the factors of the locality the 

 task of selection is frequently rendered difficult. On fertile, 

 deep, fresli soil almost any species will thrive. Again, where 

 the locality has such a decided character that only one or 

 two species are admissible, the choice is easy enough ; for 

 instance, deep dry sand points to the cultivation of the 

 Scotch or Weymouth pine, wet soil to that of the alder. 

 AVhere, however, the fertility of the soil has deteriorated, 

 for instance by the continued removal of litter, or where 

 damage by lire, frost, drought, snow, storms and insects 

 may be apprehended, it is often difficult to select the most 

 suital)le species. 



Frequentl}' the factors of the locality do not exactl}- corre- 

 spond with the requirements of any species, so that the power 

 of accommodation becomes an important element. This 

 power in the case of some species is confined within narrow 

 limits, while others can adapt themselves to all sorts of 

 conditions. For instance, Scotch pine and birch are very 

 accommodating as regards soil and climate ; spiiu-e, beech 

 and silver fir are less accommodating, and still less so are the 

 maples, alder and ash. Sometimes the jjower of accommoda- 

 tion depends chiefly on one factor; if that is not present the 

 species will not thrive. Taking for instance the temperature, 

 sweet chestnut and common elm are exacting, while Scotch 

 pine is the reverse. Oak and alder re(iuire particular degrees 

 of moisture in the soil, while birch and Scotch pine are not 

 particular. Spi-ucc prefers moist air, etc. 



5. ClKtii'ir (if the Spccirs. 



The question deserves to be mentioned here, whether in 

 sylviculture, at the end of successive rotations, a change of 

 species is advisable, or not. Change of crops is practised in 

 agriculture, because difterent species make different demands 



