248 A MANUAL OF FORESTRY. 



chiefly ill-grown, pollarded, or hedgerow trees. They 

 are only harmful in nurseries. 



The Mistletoe (Loranthus europceus) is found on the 

 branches. Fungi are numerous on Oak, but the forester 

 need not be frightened by them. Cancer appears on the 

 stem, but it seems as yet doubtful whether it is pro- 

 duced by a fungus (Nectria ditissima) or frost. White- 

 rot in the stem is produced by Polyporus igniarus and 

 Hydnum diversidens ; red-rot with white strips by 

 Stereum Mrsutum ; red-rot with white spots by Tele- 

 pJwra Pcrdix ; red, white and yellow rot intermixed in 

 elongated places by Polyporus dryadeus. Seedlings and 

 young plants are dried up by Rosellinia quercina. 



Pruning. The Oak stands pruning well, but care 

 should be taken to remove the branches while small, so 

 that the wounds may be quickly closed. 



Thinning. As pure Oak woods are generally under- 

 planted, the thinnings should be as follows : During 

 youth, say up to the age of 30 years, there should be 

 only very light thinnings or none at all. Cleanings 

 may be made to remove any undesirable species 

 threatening the Oak, such as Birch, "Willows, and 

 Aspen. After this early period the thinnings should 

 gradually become heavy, so as to develop a limited 

 number of fine trees which are to form the final crop, 

 assisted by an underwood to shelter the soil. 



4. A$SL = Fmxinus excelsior (L.). 

 a. Utility. 



The Ash yields an excellent timber, hard and heavy, 

 specific gravity when air-dried = '75, tough and durable. 



