1906J 



Combating Larch Disease. 



723 



the difficulty. He now plants pure larch woods, and when the 

 trees are sixteen to twenty years old he removes all the stems 

 except the soundest and most promising, of which 300 to 500 

 are left per acre. Needless to say, the system is inapplicable to 

 cases where all, or practically all, the trees are attacked by 

 disease at this early stage, but instances of such virulence are, 

 on the whole, of rare occurrence. The trees that are retained 

 are the picked stems of the three to four thousand originally 

 occupying the ground, and measure up to 51 ft. in height and 

 4 to 8 in. in diameter at breast-height. Stems that are sound, 

 or fairly sound, at this stage are not likely to suffer much from 

 disease in later life. The thinnings removed realise £20 to £25 

 per acre, giving a return therefor of fully £1 per acre per 

 annum from the time of planting. The thinning is done as 

 early in autumn or winter as possible, and the next step is to 

 knock off all the lower dead branches of the trees that are 

 retained. This is a rapid process, and is accomplished by means 

 of a pole some 8 ft. long. The " top and lop " of the felled 

 larches, along with the dead branches cleared off the standing 

 stems, are then thrown together into small heaps and burned. 



Owing to the shading of the dense crop of larch the surface 

 of the ground is clear of ail grass and similar vegetation, and is 

 in a very suitable condition for the reception of fresh plants. 

 Without loss of time the area is stocked with an underwood 

 which, of course, must consist of species that can endure the 

 shade of the 300-500 larches that have been retained. Mr. 

 Munro Ferguson at first used the Norway spruce, silver fir, and 

 beech, but was not satisfied with the results obtained with any 

 of these. The Norway spruce was found to grow very slowly 

 under the circumstances indicated, while the silver fir in this 

 particular locality is so much attacked by aphis (Chermes abietis) 

 as to be very uncertain in its growth. Better results were 

 obtained with the beech, and although this tree is now super- 

 seded by other species, it will probably be found to be the most 

 suitable for use on the chalk, and on calcareous soils generally. 

 But for some years Mr. Munro Ferguson has been experi- 

 menting with other shade-bearing trees, and has found that 

 Picea sitchensis {Abies menziesii), Douglas fir, Tsuga Merten- 

 siaua, Thuja gigantea, Cupressus lawsoniana, and Abies grandis 



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