50 SEEDING AND PLANTING 



of our economic broadleaved species are deficient in density of 

 foliage and do not provide adequate protection from the sun and 

 wind. Thin-foliaged, intolerant species such as poplar, locust 

 and larch are among the least effective in this respect. Dense- 

 foliaged, tolerant species such as beech and hard maple not only 

 approach conifers in their protective features but annually return 

 a large amount of leaves to the soil. Such species, therefore, lead 

 in their capacity for preserving and improving the quality of the 

 site. 



13. The Age of the Stand in Reference to the Improvement 



of the Site 



Soon after a stand closes, sufficient protection is afforded to 

 prevent deterioration in the site factors. In time, however, all 

 stands except those composed of dense-foliaged, tolerant species 

 thin out to such an extent that the canopy becomes broken and 

 open. Red spruce, hemlock, Douglas fir, white fir, beech, and 

 hard maple preserve their leaf canopy practically unbroken. These 

 and similar species can be brought to maturity in pure stand 

 without deterioration of the site and usually to its decided im- 

 provement. 



Thin-foliaged, intolerant species like locust, black cherry, and 

 white ash retain a satisfactory leaf canopy for comparatively 

 few years after the stand closes. Western larch, many species 

 of pine, various hickories, chestnut, and the oaks open up to 

 such an extent in middle life or with advanced age that they 

 are unable to preserve the quality of the site. When grown under 

 a long rotation they should be underplanted with tolerant, dense- 

 foliaged species. 



14. OTHER CONSIDERATIONS WHICH AFFECT THE 

 CHOICE OF SPECIES 



The selection of species on the basis of the foregoing considera- 

 tions is further narrowed down by the market requirements for 

 certain kinds and classes of wood and other forest products. A 

 good local demand for a particular kind of wood should always 

 have an important bearing upon the choice of species. Thus, in 

 southern New England the large demand for white pine should 

 favor the use of this species for planting purposes. In the agri- 

 cultural regions of the Middle West, the large demand for fence 



