446 Cree*s System of Pruning Forest Trees. 



When opinions on the subject of pruning are in such an un- 

 settled state, I conceive that it may not be deemed an intrusion 

 in me, to present an account of my humble efforts in this depart- 

 ment of forest culture. And I may observe, that, whether the 

 rules which I shall lay down shall be adopted generally or not, 

 I have the satisfaction of stating that they are not ingenious 

 speculations or theoretical schemes, but have been derived from 

 observations and my own practice in that system during a period 

 of nearly thirty years ; and I may add, that, in whatever light 

 it may be viewed by others, the system has, in all cases which 

 have come under my observation, been crowned with the most 

 satisfactory results. As the system which I shall lay down has 

 an especial reference to the general functions of the plant, and 

 will, I trust, always be found in accordance with the laws of 

 these functions, to make myself understood to those who have 

 not devoted attention to this subject, I find it will be necessary 

 to state shortly so much of vegetable anatomy and physiology as 

 falls within the pale of my subsequent remarks. 



In explaining the anatomy of the wood, a transverse section 

 of a young tree near the root will best show the parts to be 

 mentioned. The pith is the part in the centre, which is composed 

 of cellular tissue. Around the pith is the wood, formed of con- 

 centric cylinders, agreeing in number near the root with the age 

 of the tree. Exterior to the outmost of these is the bark, which 

 consists of three parts. The first is the outer covering, termed 

 the epidermis ; immediately below it is the soft pulpy substance 

 of cellular tissue, or parenchyma. The third is the cortical con- 

 centric layers constituting the mass of the bark, the innermost 

 of which is called the liber ; and it is between this liber and 

 the last concentric layer of wood that the alburnum is annually 

 deposited. 



The functions of vegetables, and in particular with reference 

 to the modes and offices of the ascent and descent of the sap, 

 have excited the scrutiny, and exercised the ingenuity, of physi- 

 ologists. In this field have appeared Malpighi, Grew, Hales, 

 Hedwig, Du Hamel, Saussure, Senebier, Darwin, Ellis, Keith, 

 Knight, and a host of others. When the earlier of these authors 

 wrote, vegetable anatomy and physiology were, comparatively 

 speaking, little understood ; and from the little that was known, 

 or from their own observed facts of isolated cases, the whole 

 structure of vegetable physiology was made up ; but a conside- 

 rable part of it, as was to be expected, consisted of the fanciful 

 theories of these eminent men. Subsequent researches and ob- 

 servations, however, have dispelled the mists from most of these 

 ingenious but fallacious theories, and the science may now be 

 held to rest upon a pretty solid basis, to a part of which I shall 

 briefly advert. 



