TIMBER GROWING AND LOGGING PRACTICE IN CALIFORNIA 43 
vance reproduction on areas as large as a township is almost always 
patchy, and seed trees, of course, must be relied on where reproduc- 
tion is not present. Even where it is present, the loss by logging 
and danger from fires make it essential to leave seed trees. 
THE YELLOW PINE-SUGAR PINE, MIXED CONIFER, AND YELLOW PINE-FIR TYPES 
In an intensive study of this group of types, 19 out of the 27 sam- 
ple strips, or TO per cent, gave 4 or more seed trees per acre 18 inches 
or over, and in most cases there was a good representation of trees 12 
to 16 inches in diameter. In recent years, however, the tendency to 
clear cutting has been evident on practically every operation. It 
was illustrated on 4 of the sample strips, or 15 per cent, where the 
diameter limit in cutting was well below 18 inches, and less than 1 
tree per acre of any species was left. 
NUMBE.R OF SEED TREES PER ACRE 
Fig. 16. — Distribution of trees left for seed on an area wtiere adequate reseeding resulted. 
The trees left for seed on this area ranged from 18 to 34 inches in diameter, but the 
average volume was 400 board feet, indicating an average diameter of 22 inches only. 
While 3 trees per acre was the number most commonly found (that ia on 31 per cent of 
the area), the average for this whole area of 2,000 acres in the yellow pine type was 3.9 
trees to the acre. This is a typical national forest cutting where excellent distribution 
of seed trees has been insisted on and where new reproduction indicates a correspond- 
ingly excellent distribution of seed 
In general, the results of present practice are not so discouraging 
as in the east side yellow pine type, although a deficiency in the 
number of pine seed trees is evident. In only 2 out of the 27 strips 
were 4 pine seed trees per acre left, and in only 10 were 2 or more 
left. This selective cutting, of course, will result in a decrease in 
the percentage of pine in the future stand, especially when it is 
remembered that the bulk of advance reproduction is of the firs and 
cedar, and not j^ellow or sugar pine. 
Selective cutting on private land in these mixtures of pines, firs, 
and cedars takes a wide variety of forms. The most unfortunate, 
perhaps, is one in which only unmerchantable incense cedars are left. 
From that point to where only pine is cut, leaving a heavy stand 
of fir, insufficiently opened for the development of yellow pine seed- 
lings, many variations are encountered, depending on the individual 
company's interpretation of the market for firs and cedar. 
