52 BRITISH FOREST TREES 



considerable reproductive power by means of root-suckers 

 in compensation for the natural disadvantages they are at 

 in this country in regard to the production of abundant 

 supplies of germinable seed. Of shrubs grown along with 

 forest trees in coppice, hazel and hawthorn chiefly produce 

 shoots from the stool, blackthorn mostly suckers, and field 

 maple, and most shrubs, quantities of both. Chestnut, oak, 

 hornbeam, elm, and alder retain the capacity for reproduction 

 longest l : beech, birch, maple, sycamore and ash lose it 

 soonest. Conifers have no reproductive power of this nature 

 to speak of, or which can be utilised for practical sylvicul- 

 tural purposes, although the larch in its period of youthful 

 growth can throw out shoots, and also, but to a less 

 extent, the three-needled species of pine, 2 none of which 

 form forests in Britain. 



Pollarding represents the same effort of nature to replace 

 portions of the stem cut away at some height above the soil, 

 by calling into activity the dormant buds situated below the 

 parts removed. 



6. Difference as to Age attainable. In order that in- 

 dividual trees may reach the normal limit of life in healthy 

 condition, the proper development of all the organs of 

 nourishment is primarily essential ; they must have the 

 opportunity of extending their crowns and root-systems in 

 accordance with the different demands made in this respect 



1 Recent experiments conducted by M. Bartet at Nancy show that 

 oak and hornbeam are capable of producing stool shoots up to sixty or 

 even eighty-five years of age. 



- The leaves of pines in each sheath are divided as follows : 

 Whole leaf in each sheath divided into two needles in P. sylvestris, 



Laricio, maritima, pumilio, pinea. 

 Whole leaf in each sheath divided into three needles in P. aiistralis, 



Coulteriy taeda, longifolia. 



Whole leaf in each sheath divided into five needles in P. strobus. 

 , Lambertiana, 



