460 REARING OF THE ESTAELISHED CROP. 



(b) Soil. — The influence of soil is very great indeed. In rich 

 and moist soil, casteris paribus, the faculty of completely recovering 

 «fter-continued suppression is retained much longer than in poor 

 dry soil. This is more marked, the more superficial the root- 

 system of the species in question is. A moist sub-soil is of great 

 help to most species. 



(c) Age of the advance growth, — The power of recovery is in 

 direct proportion to the age of the advance growth, as long as the 

 jstunted stage has not yet been reached. 



(d) Condition of the leaf-cano'py. — This is the most important 

 influencing factor of all. The quality of advance growth depends 

 mainly on the proper density of the leaf-canopy overhead since the 

 time of its appearance. As a rule, the best advance growth is 

 found along the edge of a forest, in gaps, and under a canopy 

 that is full of small openings ; in other words a moderately dense 

 leaf-canopy is more favourable for the appearance and survival of 

 advance growth than no leaf-canopy at all, which may be just as 

 detrimental as a very dense one. As explained several times in 

 Books 1 and II, it is of great moment whether, the density being 

 one and the same, the leaf-canopy is formed by tall, lanky, small- 

 crowned trees or by short-boled trees with deep crowns. Other 

 important points to note are the intensity of lateral illumination 

 and the time during which the advance growth has been under the 

 influence of the cover in question. 



(e) Whether the advance growth in question consists of scattered 

 seedlings or forms a group. — As a rule, only a group of seedlings 

 has any real value, but seedlings standing too close toejether are as 

 little to be trusted as those that are too far apart. The size of the 

 group has little influence on the quality of the seedlings. 



(f) Size, form and appearance of the buds, leaves and twigs, and 

 thickness and aspect of the bark. — This is self-evident (See page 

 137, para. 2) 



Nature and extent of the fostering operations. — The care 

 of advance growth must begin from the moment it makes its ap- 

 pearance under an old crop. In order to help it, whatever has to 

 be done afterwards to foster seedlings that come in as the result of 

 the regular regeneration fellings, must be done here also — pro- 

 tection against outside injurious influences, thinning out, filling up, 

 cleanings, tbe introduction in its midst of desirable species that 

 are absent or insufficiently represented. But the most important 

 thing of all to do is to take advantage of the thinnings and the 

 regular regeneration fellings for making locally, over and round it. 



