CH. II. 



COURSE OF THE SAP. 



73 



ward sap from the root are not peculiar, but general, 

 through the whole wood of the stem, to every or any 

 part or side of it, where nature, or chance, or art, 

 allows it an outlet for growth and elaboration. 



The reason of the extraordinary strength of the 

 shoots of pollards and coppice-stools is, that they, the 

 minor body, receive the sap transmitted by all the old 

 wood, from all the roots, which supply was adapted 

 and sufficient for the growth of the larger body, — the 

 head lately cut off. 



But it is only by lateral transmission that the new 

 crop of shoots can avail themselves of the whole sap 

 supplied to the stem or stool by the roots. Were the 

 channels of the sap through the wood only longitudinal, 

 the new shoots would only get the supply of those 

 vessels on which they were seated, and they would 

 have no freer growth than ordinary shoots. The sap, 

 in fact, flows freely in any and every direction through 

 the w^hole wood ; and in forest pruning, that sap which 

 Nature may be said to have intended for an amputated 

 branch, she immediately converts to the extra growth 

 of the leader and the remaining branches. Thus, where 

 tall clean timber is required, the gradual, I had almost 

 said annual^ removal of ill-placed or unduly large 

 branches does good in two ways ; for, while undesirable 

 growth is destroyed, an annual fillip may be given to 

 the growth which is desired to an indefinite period. 



A new innermost layer of bark (the new cortical Anew 



layer of 



layer) is also formed each year, from the descending ^^"^^ 



