TIMBER GROWING AND LOGGING PRACTICE IN CALIFORNIA 57 
to 50 years is in the best possible position to obtain full timber crops. 
He is then certain to remain in the lumber-producing business for 
several decades, and as his virgin stumpage approaches exhaustion, 
more and more he will be in the cut-over land business. If his lands 
are of generally good quality, they can be made to grow timber 
rapidly enough so that when the virgin forest is gone a new crop of 
wood will be ready. 
Tlie owner of extensive forests has an opportunity to grow wood 
on a commercial basis by utilizing as fully as possible the productive 
power of his cut-over lands. Such simple measures as those discussed 
in the first section of this bulletin will prevent forest detruction and 
will give the owner some real values to be used in selling or trading 
his land. But if he is to remain in the lumber business permanently 
and plans to utilize cut-over land as part of the operation, obviously 
the most profitable management will be that which produces the 
maximum stand possible at a reasonable present outlay. 
This section of the bulletin, therefore, aims to present what is 
now known regarding the best method of accomplishing this end, 
under present conditions. 
The practices developed in national forest cuttings are the prin- 
cipal basis for the discussion that follows, since it is on these forest 
properties that the most intensive effort has been devoted to obtain- 
ing full production. 
IMPORTANCE OF SITE 
The productive power of forest land, spoken of as quality of site, 
varies tremendously, and site must always be taken into account in 
deciding on the practice for any particular area. The most work- 
able method of determining site quality is by the average maximum 
height of mature trees. If, for example, the average tallest mature 
trees show a height of over 150 feet, the site quality may be con- 
sidered good; if under 125 feet, poor; and if 125 to 150 fett, medium. 
On good sites, as already noted, a rate of volume growth of at least 
3 per cent per year can be obtained on properly selected trees after 
cutting, whereas on poor sites the rate is lower. 
The owner of forest lands of generally good quality can be sure 
that a good rate of growth will be made by young thrifty trees left 
in logging in any number up to a minimum of 6,000 to 10,000 board 
feet per acre. Even trees intermediate in character between black- 
jacks and yellow pines will make profitable growth. This volume 
of timber will not seriously interfere with the rapid development of 
small reproduction, which will in turn furnish the third cut on the 
area. 
THE GROWTH OF TIMBER IN THE PINE REGION 
The actual yield of timber obtained from a particular area will 
depend on a variety of factors. All that can be done here is to in- 
dicate the range of possibilities as determined by investigations over 
a period of years. 
With the partial cutting method to be discussed, a reserve of trees 
now over 12 inches in diameter will be kept for increased growth 
and these will serve both as seed trees and as a basis of a second cut. 
For good, medium, and poor sites this reserve will average 5,000, 
4,000, and 3,000 board feet per acre. In a period of 30 years after 
logging, these trees will increase to 12,500, 8,000, and 4,500 feet per 
acre, respectively. 
