416 SYLVICULTURAL NOTES ON TIMBER TREES 



Average returns from pure crops in high forest should be, 

 per acre : 



Thinnings . . . 1160 cub. ft. to 2 in. q. g. 

 Final yield (at 90 years) . 6050 6 

 Total production . . 7860 2 

 Average annual increment, 87 J cub. ft. 



Equivalent net rental l for land only } at 3% = is. lod. 



(from date of planting) j at 4% = minus 33. 6d. 



Of Fungi. Phytophthora omnivera causes " damping off" 

 of seedlings. 



Pestalozzia Hartigii produces a canker on the bark of 

 young stems in nurseries and young plantations. The attack 

 is generally near the ground level. 



Agaricus melleus = the Honey Fungus, and Trametes 

 radiciperda (Femes annosus) = The Red Rot Root Fungus, 

 attack the roots. 



Trametes pini attacks the boles of trees, after the age of 

 about 35 years, and decomposes the heartwood and also the 

 sapwood ; though in Pines and Larch the sapwood is not 

 attacked. 



-ascidium elatinum produces "Witches Broom." This 

 aecidium is the resting spore stage of Melampsorella cerastii. 



It is characterised, in the early stages, by annular swellings 

 which appear on the twigs and branches. 



Truhosphceria parasitica = r FhQ Silver Fir Needle Blight 

 Fungus, attacks plantations when about 20 to 40 years old. 

 The young twigs are attacked and the needles turn brown 

 and hang down. 



Phoma abietina causes a canker on the twigs and 

 branches of small Silver Firs. 



Lophodermium nervisequum = The Silver Fir Leaf Scurf, 

 attacks 2-year-old needles in the spring of their 3rd year. 

 It takes the form of a rust, and afterwards causes leaf- 

 shedding. 



1 After deducting interest on 8, the cost of planting and establishing 

 the crop. 



