TIMBER GROWIXG AXD LOGGING PRACTICE IN CALIFORNIA 33 
near the machines, because low power, low-speed machines, and the 
elimination of tight-lining have been combined with a partial 
cutting of the area. 
The only possible conclusion to be derived from a study of the 
high-lead method on the ground is that with rare exceptions its use 
is incompatible with continued forest production. At least as far 
as the inner zone in high-lead logging is concerned, the ques- 
tion is not whether the new stand will be fully or only partly 
stocked, but whether there will be a new stand at all or even a 
possibility of a new stand. Destructive logging acts in the same 
manner regardless of timber type. 
Fig. 13. 
F-I57I26 
-HOW HIGH-LEAD YARDING DESTROYS YOUNG GROWTH 
By pulling out and breaking off the small trees, high lead commonly leaves 
cut-over areas with only scattered remnants of a stand. 
Modern high-power and high-speed logging is responsible for 
starting many deep gullies, which readily become enlarged through 
erosion. One serious effect of destructive lumbering is thus likely 
to be heavy erosion and reduction in summer flow of streams, a 
matter of outstanding importance to the agriculture of the Sacra- 
mento and San Joaquin Valleys. 
MODIFIED-LEAD YARDING 
The modified-lead method, with lead blocks up to 35 feet above 
ground, has not been studied in detail. Examination of areas 
logged by it shows that it is somewhat more destructive than ground 
leading, but that it does not result in the tremendous damage of 
the high lead. With low-speed machines it is a satisfactory 
method. 
74722°— 26 5 
