Pine Forests of California 



Tree classes for ponderosa pine, based on age, position, the length and width of crown, 

 form of top, and vigor factors that reflect growth, survival, and seeding capacities. 



Class l.Age class, young or thrifty ma- 

 ture; position, isolated or dominant (rarely 

 codominant); crown length, 65 percent or 

 more of the total height; crown width, 

 average or wider; form of top, pointed; 

 vigor, good. Trees of this class are rarely 

 over 30 inches in diameter, even on good 

 sites. The bark is dark brown and roughly 

 fissured into ridges or small plates. 



Class 2. Age class, young or thrifty ma- 

 ture; position, usually codominant (rarely 

 isolated or dominant); crown length, less 

 than 65 percent of the total height; crown 

 width, average or narrower; form of top, 

 pointed; vigor, good or moderate. Such 

 trees are usually less than 24 inches in 

 diameter. They are commonly the inside 

 codominant trees of groups. 



Class 3. Age class, mature; position, iso- 

 lated or dominant (rarely codominant); 

 crown length, 65 percent or more of total 

 height; crown width, average or wider; 

 form of top, round; vigor, moderate. 

 These trees are ordinarily between 18 and 

 40 inches in diameter, depending on site 

 quality. The bark is light brown or yel- 

 low, with moderately large, smooth plates. 



Class 4. Age class, mature; position, 

 usually codominant (rarely isolated or 

 dominant); crown length, less than 65 per- 



cent of the total height; crown width, 

 average or narrower; form of top, round; 

 vigor, moderate or poor. These are com- 

 monly the inside or codominant trees of 

 this age class. Except for their small 

 poorly developed crowns and smaller size, 

 they are similar to Class 3 trees. 



Class 5. Age class, overmature; position, 

 isolated or dominant (rarely codominant); 

 crown of any size; form of top, flat; vigor, 

 poor. These are usually the largest trees 

 in the stand. The bark is light yellow in 

 color, the plates often very wide, long, 

 and smooth, especially near the base. The 

 bark may be thin, having weathered more 

 rapidly than it has grown. The foliage is 

 usually rather pale green and very thin. 



Class 6. Age class, young or thrifty ma- 

 ture; 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 to 14 inches in diameter. The 

 bark is dark and rough. 



Class 7. Age class, mature or overma- 

 ture; position, intermediate or suppressed; 

 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 colored, thin, smooth. 



