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Combating Larch Disease. [march, 



THE NOVAR SYSTEM OF COMBATING LARCH 



DISEASE. 



Over the whole of Scotland and a great part of England and 

 Ireland, profitable forestry may be said to be regarded as in- 

 separable from the successful growth of the common larch. 

 But, unfortunately, in many districts this tree has of recent 

 years proved so susceptible to the attack of a fungal disease that 

 it can no longer be depended on to give a full crop of timber, and 

 resort has been had to several sylvicultural systems with a view 

 to preventing or mitigating the trouble. The practice that has 

 been most generally recommended is to mix the larches with 

 some dense-crowned species (spruce, silver fir, Douglas fir, 

 or beech), the intention being to surround each individual larch 

 with other species immune to disease, so that should the parasite 

 appear on any particular tree the chances of the spores spread- 

 ing to other trees of the same species would be reduced to a 

 minimum. Incidentally, this system possesses the additional 

 advantage of associating the larch — a thin-crowned, light- 

 demanding tree — with other species having dense foliage. . As 

 a consequence [the ground is more completely shaded, weeds 

 and ground vegetation are suppressed, and the area is furnished 

 with a thick covering of dead leaves (forest humus), which 

 greatly improves the conditions of growth for the larch. Un- 

 doubtedly such a system of management has proved an advan- 

 tage to the larch, but it has not in all cases sufficed to protect 

 this tree against disease. Moreover, it is evident that if each 

 larch is to be effectively isolated in this way only a comparatively 

 small number of plants of this species can be accommodated 

 on an acre, and if the local demand for the other species is 

 unsatisfactory, the financial result of the system as a whole may 

 leave much to be desired. Such a system of mixing, too, tends 

 to the production of coarse timber by the shade-bearing species, 

 whose lower branches are not killed sufficiently early under the 

 mild shade of the larch. 



Dissatisfied on the whole with the results of even-aged mixing 

 of the larch with other species, Mr. Munro. Ferguson, of Novar, 

 has for some years practised a system in his extensive woods in 

 Ross-shire which promises to provide a satisfactory solution of 



