306 GEOLOGICAL SURVEY OF NEW JERSEY. 



" alios," which formerly arrested vegetation, in no way impeded 

 growth. It is a sandstone, not entirely impervious, and served 

 to hold the moisture during the dryness of summer. It was 

 feared that the inability of the tap-root to penetrate this hard- 

 pan would arrest the growth of the tree, "but," says Chambre- 

 lent, " the uselessness of the tap-root * has already been demon- 

 strated. It extends to inert soil which receives no atmospheric 

 influences. It really plays only a mechanical role for holding 

 the tree in place, but in close growth is not necessary, because 

 the trees support each other." 



He also notes the fact that in spite of very rapid growth the 

 wood is of superior quality. In another place he says that 

 owing to its elasticity, the poles are in great demand in England 

 for mine props, also that because of its rapid growth, the absorp- 

 tion of copper sulphate is facilitated, which renders it durable 

 and valuable for telegraph poles. In speaking of the sanitary 

 effects of the forest he says that "the Landes, which in 1865 

 were pestilential, are now as free from fever as the most favored 

 regions. The presence of so much wood enables every house- 

 hold to have generous supplies for heating and drying in cold 

 and wet seasons. An investigation of the causes of agricultural 

 depression in other parts of France only too clearly indicates the 

 inestimable benefit of large wood-supplies for domestic pur- 

 poses." 



During the Civil War in America, France enjoyed a broad 

 market for her naval stores at three times the normal price. 

 Owing to the cheapness of the inferior American product, gem- 

 mage or tapping for resin is not very profitable. 



Such was the work started by Chambrelent. By allowing a 

 revolution of thirty years to the pine crops it may go on forever, 

 provided forest fires and insect pests are kept in check. Planta- 

 tions of coniferous species in all dry countries are always in 

 danger of fire, and forests of one species only are often com- 

 pletely devastated by insects. 



By the fixation of the Dunes 650,000 hectares of land were 

 made productive. Formerly if one wished to buy land, he 

 mounted a hill and called in a loud voice ; the land over which 

 his voice carried was worth twenty-five francs. 



* Gardeners often remove the tap-root of trees in order to stimulate the horizontal root system and 

 to facilitate transplanting. 



