HEART-ROT IN CONIFERS. 4L 



in Norway spruce. Fortunately, this wood contains a fair 

 proportion of hardwoods. 



In a 26-year-old Douglas fir stand in Kincardineshire, 

 which has been grown under very close conditions, the 

 percentage of thinnings showing either incipient or severe heart- 

 rot was 35 per cent, in one plot and 32 per cent, in another. 

 The soil here is of glacial origin and is of a moderately 

 heavy type. There are numerous old decaying stumps of a 

 previous crop on the ground. It is noteworthy that where 

 the heavy thinning was made, trees of all sizes were cut and all 

 showed the same proportion of stems attacked. 



On another area in the north a crop of pure Abies gra^idis 

 exists, now 20 years old. The stocking has all along been 

 exceptionally dense, and the general appearance of the stand is 

 excellent. Old stumps of a former crop of larch and Scots pine 

 occur throughout the wood. A heavy thinning was made in 

 one half of this area during this autumn, and the percentage of 

 stems with more or less severe heart-rot was 32. Fructifications 

 of Fomes annosus were found on one tree of average size, which 

 had been killed. A few others were also dead from the same 

 cause. In this wood, it was very obvious how the trees attacked 

 were generally collected in proximity to old stumps. On many 

 of these old stumps there were numerous large fructifications. 



It is noteworthy that in all the above cases the woods were 

 exceptionally good, well-stocked, and, to all outward appearance, 

 healthy. If completeness of stocking and rate of growth are to 

 be taken as the indication of the correct selection of species, 

 then in all the above cases no fault could be found on these 

 counts. Yet in every case, at ages varying from 15 to 45 years, 

 a serious hidden disease of economic importance was present. 

 If this sort of thing occurs to this extent in what are considered 

 to be good plantations, the conclusion is inevitable that it is 

 probably more frequent in inferior plantations. Individual 

 foresters can, no doubt, supply more details from their own 

 experience. The gravity of such a state of affairs is at once 

 apparent. 



In considering methods of fighting this serious forest pest, it 

 seems that the possibility of eradicating it, when it once attacks 

 a growing wood, is remote. As stated above, preventive 

 iTJc^.sures taken before the wood is planted up form the sole 

 lemedy. 



