26 FOREST SYSTEMS 



existing crop, which has been heavily thinned. Only thinly 

 foliaged trees, such as Oak, Ash, and Larch, should be 

 underplanted, and the trees used for the undercrop should 

 only be shade-bearing trees. Silver Fir, Beech, and Horn- 

 beam will bear the greatest amount of shade, and then 

 perhaps Thuya gigantea ( T. plicata). These trees will usually 

 form the undercrop. 



If, however, the canopy is thin, Douglas Fir or Weymouth 

 Pine, or Spanish Chestnut may be used. Norway Spruce 

 cannot be recommended, as, in this country, it is not tolerant 

 of much shade, and it robs the overwood of too much 

 moisture. 



Under the orthodox method the two crops are harvested 

 at the same time ; but there is no necessity for such a course. 

 If desired, the older crop can be removed and the younger 

 crop can be allowed to grow on, until of larger dimensions : 

 for if the trees forming the older crop are well grown and 

 have not unduly large crowns, little harm will be done to the 

 younger crop, especially if it consists of good stout poles. 



Where Ash is underplanted, it must almost always be 

 removed before the undercrop, as it comes to maturity so 

 early, viz., from 60 to 75 years. 



(c) High Forest with Coppice. 1 This system is some- 

 what similar to the system of two-storied high forest, but it 

 involves the periodic cutting over, at ground level, of the 

 undercrop. 



The standards must consist of only thinly foliaged trees, 

 such as Oak, Larch, Ash, Black Walnut, and Black Poplars. 

 The most suitable trees for the coppice are Spanish Chestnut, 

 Hornbeam, Ash, and Alder, and to some extent Beech, but 

 the stools of the latter are not usually long-lived, and its 

 produce, unless large, has not much value. 



The essential points in which this method differs from 

 ordinary coppice with standards are, that the standards over 

 a given area are all of one age, and thus height growth is 



1 This system has been named and recommended by the author as a 

 substitute in many cases for the more common system of coppice with 

 standards. 



