SESSILE- FRUITED OAK. 



277 



secure its portion of light and air ; its growth is therefore 

 for many years principally confined to the elongation of 

 the trunk or main stem ; this, together with the confined 

 space to which it is restricted, prevents the vigorous growth 

 and great enlargement of the lateral branches, which al- 

 ways takes place in single trees, or where they have 

 space and air. Indeed the difficulty is to induce the 

 Oak in plantations to retain lateral branches sufficient 

 to maintain and support it in vigorous health, and this 

 can only be effected by oft-repeated thinnings to admit 

 of sufficient light and air, and prevent too close an in- 

 terference of other trees with its growth and head room ; 

 for how often do mixed plantations meet the eye wherein 

 the unfortunate Oaks, from want of air and timely thin- 

 ning, are drawn up to long consumptive-looking poles, 

 entirely divested of their lateral branches, or as it were 

 deprived of a portion of their lungs, and barely kept in 

 a lingering state of existence by the few top-most shoots, 

 that in the struggle for life have forced their way to 

 the light. 



At Twizell, where thinning has been freely administered 

 and carefully attended to, the Oaks in plantations of about 

 thirty years old have run up with fine straight stems, 

 many of them full thirty feet in length, and still carrying 

 an upright leader. All these, however, still retain a 

 portion of their lateral branches, which assist so essentially 

 in the important functions of conducting and elaborating 

 the sap, and without which the deposition of the woody 

 fibre cannot be effected to the extent necessary to the 

 health and vigour of the tree ; these laterals, we expect, 

 will retain their vitality so long as the trees require and 

 are benefited by their presence, their removal or decay 

 only taking place gradually, or as the upper branches 



