156 INTERMEDIATE CUTTINGS — THINNINGS 



in the stand, and with crowns well-developed but possibly 

 somewhat crowded on the sides. 



Co-dominant. — Trees with crowns forming the general level 

 of the forest canopy and receiving full Hght from above but 

 comparatively little from the sides; usually with medium- 

 sized crowns considerably crowded on the sides. 



Intermediate. — Trees with crowns below, but still extend- 

 ing into, the general level of the forest canopy, receiving 

 a little direct light from above but none from the sides; 

 usually with smaU crowns considerably crowded on the sides. 



Overtopped. — Trees with crowns entirely below the gen- 

 eral forest canopy and receiving no direct light either from 

 above or from the sides. These may be further divided 



Oppressed. — Usually with small poorly developed 

 crowns still alive, and possibly able to recover, and 

 Suppressed, or dying and dead. 



The silviculturist, while recognizing the value of the strug- 

 gle for existence in assisting the production of lumber free 

 from knots, attempts by making thinnings, to avoid its dis- 

 advantages of lessened production and inclusion of undesirable 

 species and trees of poor form in the final stand. 



Advantages of Thinnings. — The advantages of thinnings 

 applied in the stand as compared with Nature's unrestricted 

 competition can be summed up under the following headings: 



I. The length of time required to grow products of the 

 desired sizes can be shortened by the use of thinnings. This 

 is accomplished through an increase in both diameter and 

 height growth coming as a consequence of eliminating strong 

 competition between individual trees. The trees remaining 

 after the thinning have room to expand their crowns and 

 root systems and secure large supplies of food, instead of 

 fighting with numerous associates for part of the same total. 



