128 TRANSACTIONS OF ROVAL SCOTTISH ARBORICULTURAL SOCIETY. 



of this region, and known as the gra vosgien. The soil is 

 consequently extremely porous, and great care has to be 

 exercised in keeping it continually covered with a crop dense 

 enough to exclude the sun's rays from parching it, and making it 

 less fertile. 



Here the silver fir is worked with a rotation of 144 years, and 

 regeneration is brought about naturally. 



The forest is divided into four periodic blocks of 36 years each, 

 and the fellings are done by volume. 



In thinning for regenerating purposes, more care has to be 

 exercised than if the crop were of any other kind. Silver fir 

 being rather tender while very young, the seedlings require a 

 considerable amount of shelter from the parent trees, whose 

 heavy shade they endure well for the first few years. 



The plan usually adopted is to make light gradual clearances 

 every three or four years, cutting away the heavier or broad- 

 crowned trees, and gradually exposing the young seedlings to the 

 light. 



Wherever regeneration-fellings had taken place, it was 

 interesting to notice how luxuriantly the young seedlings were 

 establishing themselves, and how evenly they were distributed 

 over the open areas. 



If one were to criticise the method by which those regenera- 

 tion-fellings are being made, it would be to advocate the system 

 of felling by area, instead of by volume. Many thousands of 

 over-mature trees were seen standing in this forest, where they 

 are no longer even required for seeding purposes. Obviously, 

 these trees are deteriorating in value, and their ultimate removal 

 will seriously interfere with the younger crop. This fault would 

 be much more easily remedied if the working-plan provided that 

 the final fellings were to be done by area, instead of by volume. 



Thinnings are made every 10 years, when suppressed and 

 inferior trees are gradually removed. 



Thinning on such high altitudes requires to be very skilfully 

 performed in order to prevent wind-fall. But in spite of all 

 the precautions taken in this respect, the efforts are not always 

 successful, as in this forest alone about 9,000,000 cubic feet of 

 timber have been uprooted by recent gales. 



In one section, at present only 60 years old, the trees were 

 found to measure, on the average, 90 feet in height, while the 

 estimated growing-stock per acre is computed at 5000 cubic feet. 



