OBSERVATIONS ON ROOTLET DEVELOPMENT IN YELLOW BIRCH

Under a closed stand the presence of organic material is more important than the prevailing temperature in determining whether a specific volume of soil is occupied by yellow birch rootlets. Most of the organic matter under stands containing birch in the Maritime Provinces is contained in the humus layer, which is rarely more than 6 cm. thick. In pure hardwood stands containing a high proportion of yellow birch, over 75% of the rootlets were found in the humus layer. In hardwoods containing less birch or in stands containing a high proportion of conifers, over 90% of the birch rootlets were in the humus.