412 The Trees of Great Britain and Ireland 



method The pine usually occurs pure ; but in the ravines small and unimportant 

 groups of silver fir are often seen, and the edges of the streams are bordered m many 

 places by Ahms cordtfolia. The beech in Corsica attains as high an elevation as 

 Laricw, and in some cases the two species are mixed, and a struggle occurs for pre- 

 dominance. Birch is occasionally a component of the pine forest, but is compara- 

 tively rare. The soil on which Laricio grows is usually extremely poor, consistmg 

 of debris of granite rocks, and contains very little humus or decayed vegetable 



matter. 



The following observations which were taken in 1906, at 3200 feet altitude, m 

 the midst of the Laricio forest at Vizzavona, show the climate in which the tree 

 thrives : — 



Snow and low but not extreme temperatures are common during nearly six 

 months of the year, from November to the beginning of May. The sky is generally 

 clouded more or less completely during a greater part of the year ; a clear blue sky 

 only being recorded on 77 days out of the whole year. 



The Laricio forests are easy of access, owing to the railway, which goes through 

 the heart of the mountains from Ajaccio to Bastia ; and in spite of a heavy fall of 

 snow I succeeded in seeing some of the most important forests in the last week 

 of December 1906. The finest is Valdoniello, which lies about twenty miles west of 

 Corte railway station, the road to it passing through the magnificent gorge of the 

 Scala di Santa-Regina. This forest occupies the upper basin of the river Golo, 

 which has a north-easterly exposure, and its wooded area covers 6682 acres lying 

 between 3100 and 5100 feet altitude. The soil is very dry and extremely poor, con- 

 sisting of granite debris ; and the few beech and silver fir that were seen could only 

 obtain a footing in the ravines. The forest is divided into two series, one of which, 

 about 4000 acres in extent is being regularly felled, whilst the other series at 

 a greater elevation is left untouched as a zone of protection. In the first series 



