166 THE PRINCIPLES OF HANDLING WOODLANDS 



quired to continue the operation which has already 

 been started. In the secondary cutting more trees are 

 taken from over the existing groups, according to their 

 need, and the newly reproduced circle is opened up by 

 a heavy removal thinning. The portion which was in- 

 cluded in the previous preparatory cutting is thinned for 

 seed, and if necessary a preparatory cutting is made still 

 farther into the woods. These secondary cuttings are 

 made not necessarily in all groups at the same time, but 

 in any groups whose condition requires treatment. The 

 result of the gradual extension of these groups is that 

 they ultimately are merged together, and the whole stand 

 is reproduced. 



As a rule, a long period of reproduction is used to 

 work over a whole stand usually from 30 to 40 years. 

 The result is a stand much less even-aged than that ob- 

 tained by the other methods. The advance growth is 

 often from 20 to 30 years old, thus making a total varia- 

 tion in age in the new stand of from 50 to 60 years. In 

 spite of the wide difference in the age of the trees, the 

 new stand is essentially regular in character, and is in no 

 sense a selection forest. 



The Two-Storied System 



This is an intensive system used in Europe, having 

 for its object the isolation of the best trees during the last 

 half of the rotation in order to secure a maximum growth 

 in diameter and volume. It is applied to even-aged 

 stands of species which are windfirm and which have 



