78 



CIRCULAR 3 3 3, U.S. DEPARTMENT OF AGRICULTURE 



Scarcely any nodes are distinguishable. Nearly all the branches are drooping, 

 gnarled, and crooked. 



Class 6 : Age class, young or thrifty mature ; position, intermediate or 

 suppressed; crown of any size, usually small; form of top, round or pointed; 

 vigor, moderate or poor. 



These are understory trees, rarely over 12 or 14 inches in diameter. The 

 bark is dark and rough. The top is round or pointed, showing that some 

 height growth is taking place. Whorls of branches are evident, though the 

 internodes are short. 



Class 7: Age class, mature or overmature; position, intermediate or sup- 

 pressed ; crown of any size, usually small ; form of top, flat ; vigor, poor. 



These understory trees are rarely over 18 inches in diameter. The bark is 

 light in color, thin, and smooth. The top is flat, the terminal rarely dis- 

 tinguishable. The foliage is excessively thin. The few branches present are 

 gnarled and drooping. 



SWEDISH TREE CLASSIFICATION (34) 



1. Dominants — Trees of dominant class, i.e., the tallest trees in the stand. 



2. Codominants — Trees of somewhat less height and thinner crowns and gen- 

 erally more slender boles than class 1 trees. The heights run from about two- 

 thirds to five-sixths of the heights of the dominant trees. 



3. Suppressed — Trees the height of which ranges from one-half to two-thirds 

 of the height of class 1 trees. The leaders are usually short. In even-aged 

 stands this class includes the slower-growing trees of the predominating age 

 class. 



4. Understory — Trees the height of which does not come up to half that of 

 class 1 trees. This class includes the smaller suppressed trees (of younger age 

 classes in uneven-aged stands, or advance reproduction of sapling size). 



Figure 5. — Swedish tree classification for conifers. 



In addition, the following symbols are used : r, reproduction of less than 

 sapling size ; O, overstandards. Overstandards are trees of an older age class 

 (usually 30 or 40 years older than the main stand), usually considerably taller 

 and of greater diameter than the other trees in the stand. 



A tree with a well-formed crown and with a good bole is entered without any 

 notation other than the number of the tree class. Other trees in each of the 

 crown classes are further classified, with reference to the character of the crown 

 and the form of the bole, by letters, as follows : 



a. Trees with one-sided crowns. 



b. "Wolf " trees of better quality, with large, low-hanging branches. 



c. Crooked or twisted trees, forked trees, poor-quality " wolf " trees. 



d. Trees with crowns suppressed or damaged owing to influence of adjacent 

 trees. 



e. Trees in a sickly condition owing to damage by insect, fungus, fire, or 

 other agency. 



f. Dead, broken, or heavily snow-damaged trees. 



