2^2 TBEES ; THEIR FORMS, ETC. [^eb., 



this as their primary function. It has even been suggested that 

 nurses may be used only when the forest is in a locality where small 

 tiinber commands ready sale. This suggestion si] uints badly ; it has 

 ' one eye on the pot and another up the chimney,' it wot)S the cook 

 and watches the butler. According to it, the employment of nurses 

 is contingent and arbitrary, and not a cultural necessity. The 

 employment of nurses to produce timber of good quality is not 

 arbitrary. Their primary function is the regulating of horizontal 

 light and the directing of growth. As growth resiles from the shaded 

 side of a tree and seeks the unshaded side, so, when all sides are 

 shaded, growtli resiles from all sides and seeks the light of the 

 zenith. The magnitude of the resilience is as the density of the 

 shade. Herein is the secret of timber culture ; and herein is the 

 function of nurses. 



From such a forest we further learn what place in the culture 

 of forest trees pruning ought to occupy. Cutting off wayward 

 branches becomes unnecessary where the conditions opposed to 

 wayward side-growth are preserved. Superior quality in timber is 

 not a product of whetted steel. In horticulture, where a certain 

 precocity in the fruit tree is necessary to success, pruning may be, 

 and is, practised with unquestionably good results ; but in sylvi- 

 culture, where precocity is displaced by normal vigour of a tree, its 

 practice, except in very special cases, should be dispensed with. 

 We entertain a suspicion that sylviculture borrowed the practice 

 of pruning from horticulture, and are not without hope that the 

 article will in due time be restored to its rightful owner. Many 

 British methods of sylviculture, which exist simply on the ability of 

 Britain to practise them, and of certain trees to endure them, will 

 cease to exist when British sylviculture renounces itself in some 

 measure, and when its friendship with Nature waxes strong. 



Time forbids not only our dealing with the forms of trees as affected 

 by cold and concussion — two laws over which the culturist has 

 limited control — but also our reviewing the part played by these laws 

 in the distribution which has been made of trees over the earth's 

 surface. In concluding, we are not unmindful that the ascribing of 

 positive results to laws negative in their character, is very distasteful 

 to certain individuals. They reason in this way : that as darkness, 

 for example, is the absence of light, it must be destitute of results. 

 We have found such persons mighty in the use of the argwnentum 

 reductio ad ahsurdum, and have been always careful not to argue 

 with them. But while the lawyer enjoys his negative prcrjnant, and 

 the mathematician his ^cro with nuims quaiiiiticn, we naturalists may 

 surely entertain our result of negation. After all, one cannot con- 

 ceive a negative condition. Every condition that exists must be a 



