534 forestry Quarterly. 



aged Yellow Pine. It is difficult to conceive of typical soil in the 

 Yellow Pine type bearing a stand per acre of over 100,000 board 

 feet per acre, and there can be no doubt but that a great falling 

 off in growth, or practically a standstill occurs after about 80' 

 years. Increment will be balanced by the dying out of many 

 trees. Since not sufficiently large plots for an accurate yield 

 table could be obtained, the table has been made most conserva- 

 tive, and falls far short from showing the maximum yields which 

 were obtained during the growth study. The figures neverthless 

 show that the growth of Yellow Pine in even-aged stands is very 

 rapid, equalling that of White of Loblolly Pine. They show, 

 moreover, that it is by no means impossible that the rotation of 

 Yellow Pine may best be near 100 years rather than the much 

 longer times that have been assumed for this species. 



Second growth pine suffers from most of the destructive agents 

 encountered in the virgin forest. The worst damage, however, 

 is caused by snow, which in this region falls heavily laden with 

 moisture causing it to pile immense weights on the trees, rather 

 than sifting through and falling upon the ground. Yellow Pine 

 is well rooted but its rapid height growth in even-aged stands 

 makes it peculiarly susceptible to breakage. The weight of the 

 moisture laden snow proves too much for the trees to bear, and 

 tops 10 to 30 feet in length frequently broken off. Once started 

 in a stand, breakage becomes general and every heavy snowfall 

 is attended with serious damage. For this reason, thinnings will 

 always be attended with great danger to the remaining stand and 

 will necessarily be very light. 



Deep soil is essential to the rapid growth and most emphatically 

 to the reproduction of Yellow Pine. The roots must penerate 

 below the surface layers which feel the drying effect of the long 

 summer's drouth. Therefore, any agency lessening the water con- 

 tent may so disturb equilibrium as to render the soil incapable of 

 supporting seedling growth. Areas of insufficient soil depth are 

 characterized by scrub growth upon which pine encroaches with 

 exceeding slowness or not at all. Temporary deterioration of 

 soil quality through various causes is followed by scrub wood in 

 its temporary form. In such cases the ease of regeneration de- 

 pends upon the degree to which the brush absorbs the soil mois- 

 ture, hence not only the amount of scrub growth but upon the 

 species represented. In general, the better the soil the more easily 



