10 



CALIFORNIA TANBARK OAK. 



uncommon in the best parts of the southern Humboldt and northern 

 Mendocino district, where the stand in limited areas is nearly pure 

 tanbark oak. The largest amount of bark ever reported from* one 

 "claim" was 1 ; 284 cords, or 8 cords per acre. 



In estimating tanbark in the Santa Cruz, Mendocino^and southern 

 Humboldt districts cruisers generally count 6 tree^to the. cord, 

 though sometimes the trees are so large that it takes 'only 4*ito pro- 

 duce a cord. In the northern Humboldt' district 8 or 9 trees /make 

 a cord and hi the Klamath 14. Cruisers are more likely to under- 

 estimate than to overestimate a claim. Exceptionally large trees 

 with thick bark produce from 2 to 3J cords of**bark. The figures 

 given in Table 2 are from trees on the inner edge of' the redwood belt. 



TABLE 2. Amount of tanbark on oak trees of different sizes. 



To avoid discrepancies due to loose piling, the "cord" used in 

 selling tanbark is reckoned by weight rather than by dimension, and 

 is approximately a ton, though it varies in different localities from 

 2,200 to 2,600 pounds. It is most commonly 2,400 pounds, which is 

 the standard accepted in San Francisco. For bark that has been 

 peeled a year, 2,300 pounds is considered a ton. Very rarely a cord 

 is measured by dimensions; but where it is, as at Arcata, for instance, 

 it is 8 feet long, 4 feet wide, and 4| feet high. 



PEELING. 



The peeling season runs from about May 20 to about August 10, 

 but varies with latitude, weather, and locality. Peeling can be 

 started any time after the sap begins to run and continues during the 

 period of summer growth. Tanbark oak is extremely sensitive to 

 heat and cold as regards the adhesion of its bark. A cold spring 

 -delays the opening of the peeling season and a cool, moist summer 

 prolongs it. Trees on the shady north slopes will peel later than 

 those on the ridges or south slopes, but one of the periodic north 

 winds of the Coast Range, which are hot and dry, will make peeling 

 difficult or cause some trees to bind down completely. Cold nights, 

 on the one hand, will make the bark stick, and a hot period in July or 

 August will put an end to peeling. Trees standing side by side often 



