268 Forestry Quarterly. 



protection against moving sand ; and as having great economic 

 importance since they are the sole source of fuel and building 

 material. The important species are listed and their distribution 

 described. 



T. S. W., Jr. 



Revue des Eaux et Forets, January i, 1914, pp. 105-109. 



LeBressan generalizes on the impover- 

 Forests ished condition of Spanish forests. After 



of commenting on the varying acreage as re- 



Spain. ported by different writers, he reviews the 



damage which has resulted from overcut- 

 ting and overgrazing. Most of this damage seems to have re- 

 sulted from the substitution of goats for sheep. 



J. S. W., Jr. 



Bulletin Societe Forestiere de Franche — Comte & Belfort, March, 1914, 

 pp. 312-315- 



SOIL, WATER AND CLIMATE. 



The depth to which the soil is open 

 Soil enough to allow the penetration of tree 



Physiology. roots does not always determine the dis- 



tance the roots descend. In other words, 

 the absolute soil depth and the physiologic soil depth are not 

 necessarily equal. It is only the moist, crumbled, well aerated 

 soil which contains a high percentage of the organic matter that 

 supports root growth. A compact, sticky soil and a too open 

 sandy soil without humus alike prevent root growth. 



The distribution of the soil water is a most important factor. 

 Trees require a large amount of water, but also the drainage 

 must be good. In fact, xerophytic plant formations are found 

 on sandy soils under which the water table is high because it is 

 only the top layer of soil which is well enough aerated, and that 

 drys out rapidly on account of its sandy character. 



The following table shows the relation of soil depth to site 

 quality for pine: 



