130 FOREST PROTECTION 



Avoidance of dense stands in seed beds (ash seed- 

 lings at Biltmore failed to lignify in 1905, 

 excepting those at outer edge). 



2. In plantations: 



Remark: A seedling once crippled by frost is 

 apt to be crippled again, and again, and 

 again, owing to the fact, that the replace- 

 ment of organs once lost takes time; so that 

 the growing season is shortened. The wal- 

 nuts and buckeyes at Biltmore, once clipped 

 back by frost have been clipped back an- 

 nually. 



Early planting in spring to avoid early frost; 



Late planting in spring to avoid late frost; 



No experimenting with the introduction of new 

 species; 



Natural regeneration of Pinus echinata (also 

 White Pine in Adirondacks) to avoid for- 

 mation of double whirls; 



Planting sensitive species beneath a light cover 

 overhead, so as to prevent excessive height 

 growth, or premature formation of spring 

 shoots. 



Use of strong stocky seedlings, since minute 

 plants are prevented from lignification by 

 shading weeds. 



Selecting species suiting the soil (walnut on best 

 soil, where it will lignify; echinata on poor 

 soil, where it will form one shoot only), 

 the exposure, and the climate (prairie plant- 

 ing); 



Cultivation, so as to stimulate insolation and 

 lignification; possibly pruning to same end; 

 or else to give the lead to one side shoot 

 amongst several when the leader is frost- 

 killed. 



3. In natural seed regeneration: 



Progress of the axe in shelterwood-types accord- 

 ing to the requirements of the seedlings, 

 viz., slow, where late frost is feared, so as 

 to retard the act of sprouting in spring; 

 or else rapid, where early frost is feared, 

 so as to allow of lignification; 



Untimely and sudden removal of mother trees 

 may shock tender plants (even spruce 5' 

 high), on the other hand. 



