78 PROTECTION OF WOODLANDS. 



The cutting out of all cankerous poles and stems is to be 

 recommended at the time of making thinnings, and even special 

 fellings should take place with this object when the disease is 

 frequent in any crop ; the removal of the twig-clusters, by means 

 of which the disease is reproduced and extended, should also be 

 carried out as far as possible. 



The Pine-shoot Fungus (Caeoma pinitorquum) principally attacks 

 young Pine woods of 1 to 10 years of age, although young crops 

 up to about thirty years old are liable to be attacked. Pale yellow 

 spots, bearing the spermogonia of the fungus, make their appear- 

 ance about the beginning of June on the green epidermis of the 

 young shoots. With the development of the sporophore under the 

 bark, this is raised up in pustules, and finally fissures longitudinally, 

 whilst the cellular tissue dies as far down as the woody fibrous tissue 

 below the spore-bearer's. At the diseased place the shoot assumes 

 somewhat the shape of S, but raises itself again at the apex. 

 When this process is repeated, as can be particularly favoured by 

 damp weather in May and June, the Pines often become com- 

 pletely deformed, a portion of the shoots dies off, and the young 

 plants have somewhat the appearance of having been badly 

 damaged by late frost. 



The removal of any Aspen that may be growing in Pine woods 

 affected with this disease is recommended, as the Poplar rust 

 (Melampsora Tremulte) occurring on the leaves of the Aspen is 

 considered the cause of the pine-twisting. 1 



The Tree-fungi (Polyporus) are partly saprophytic, living only 

 on dead wood, partly also true parasites, and causes of disease and 

 rotting of timber. In this latter case their mycelium develops in 

 the interior of the stem, whilst the well-known spore-beds of different 

 shapes, often bracket-like, are situated on the outside of the stem. 

 The timely removal of trees thus infected with fungus is advisable, 

 not only in order to have any use from the timler itself, but also 

 to prevent the further spread of the disease through the forma- 

 tion and scattering of spores. 



Canker of the Larch (Peziza WillJcommii) is a very widespread 

 disease, causing the sickening and death of many Larches, and, 

 according to Hartig's opinion, the chief reason of the unfortunate 



1 The Caeoma is polymorphous, the spores of C. pinitorquum producing 

 Melampsora tremulx with the Aspen as a host, whilst the Teleuto-spores of the lat 

 form of the fungus cause infection with C. pinitwquum in the following spring. j 



