Chap. V] 



THE SOIL 



97 



The observations were carried on in the forest of Champfetu near Sens, where 

 on a small area, calcareous soil (chalk) and silicious soil (sand and sandy clay) 

 alternate, because the clay and sand overlie the chalk, as tertiary strata, forming 

 sometimes a thick deposit and sometimes a thin one, or have been completely 

 washed away. The area in question had been planted with different species 

 of forest trees, such as Pinus sylvestris, P. Laricio, larch, silver-fir, spruce, oak, birch, 

 which had for the most part thriven equally well on each of the strata : whereas the 

 maritime pines and sweet-chestnut trees that had also been planted grew luxuriantly 

 on the soil that was poor in lime, but remained stunted on the calcareous soil and 

 soon died ; and so much the sooner, the thinner the upper stratum poor in lime. 

 Wherever the sandy soil poor in lime was absent, both trees could scarcely live 

 at all. 



The chestnut trees and maritime pines on the calcareous soil differed from those 

 on the sandy soil, not only by their stunted growth and by the abundance of their 

 dead twigs, but also by the smaller size and the yellower colour of their leaves, which 

 in the case of the chestnut were partly white. Thus on silicious soil the pine needles 

 were 0-175-0-189 m. long and 2 mm. broad, whilst on calcareous soil the length of the 

 needles was between 0-092 and o-iii m. and their breadth 1-5 mm. The chestnut 

 leaves on clay and sandy soil were up to 0-253 m - l° n g ar >d 0-072 m. broad, but on 

 calcareous soil at the most 0-149 m - l° n g an d 0-056 m. broad ; those at the end of the 

 twig were much smaller, often degenerate and nearly white. 



The analysis of the soils from which the specimens of Pinus Pinaster had been 

 taken, the composition of whose ashes will be given below, gave the following 

 results : — 



ANALYSIS OF SOILS IN THE FOREST OF CHAMPFETU UPON WHICH 

 PINUS PINASTER GREW (after Fliche and Grandeau). 



In the analysis of the ash of the maritime pine grown on these soils, about equal 

 volumes of wood, bark, and leaves were used. For the purpose of comparison, Pinus 

 Laricio, which prefers a lime-containing substratum, was taken from the calcareous soil 

 and analysed. 



H 



