KNOT ZONES AND SPIRAL IN ADIRONDACK RED SPRUCE 779 



than one inch in forty inches, one inch in thirty to forty, one in twenty 

 to thirty, one in fifteen to twenty, or spiraled more than one inch in 

 fifteen. The number of rings in the last inch of average radius on the 

 stump was counted and recorded. Direction of spiral was designated 

 as left if it went counter-clockwise around the bole in looking up the 

 tree and right in the reverse direction. A special effort was made to 

 secure data on the larger diameter classes, so that the number would 

 equal as nearly as possible the smaller classes. 



Data were taken from standing trees for diameter classes less than 

 eight inches. It was found possible to measure the degree of spiral 

 from a very small bark incision. In this way it developed that the inner 

 bark had fiber aligned with that of the wood adjoining it, while the 

 direction of fiber in the outer bark might not conform in direction or 

 degree of spiral. The instruments used were ordinary calipers, a 

 straight eight-foot measuring pole, and a small scale. 



The same method was used in securing measurements at Brandreth 

 Lake on 384 trees, except that degree of spiral was measured in exact 

 per cents instead of being grouped into classes — that is, a spiral of one 

 inch in twenty was designated as 5 per cent. An additional measure- 

 ment of the clear zone was taken on the opposite side of the tree from 

 the first knot, and the average height of the clear zone was found to be 

 about three feet above the first knot. Per cent of spiral was measured 

 on a total of 1,314 trees at Brandreth Lake. 



• 



DISTRIP.UTION OF KNOTS 



The diagrams shown are the result of the study at Cranberry Lake. 

 Difference in results are pointed out in all cases where the continuation 

 of the study at Brandreth established contrasts with the first study. 

 The general trend of results was the same. 



The study of knot distribution is based on tlie assumption that the 

 standing merchantable trees cleaned their boles at the same rate as the 

 smaller diameter classes are now doing. While it is recognized that 

 there will be a certain mortality among the smaller diameter classes, 

 there is no evidence of direct relation between this loss and knot dis- 

 tribution. 



Three factors determine thr extent of the clear length — size of the 

 limbs, rate of decay or erosion in the dead limbs, and the rate at which 

 overgrowth has taken place in a radial direction. The varying influ- 

 ences of these three factors determine the limit of the first three zones 

 in the log di.-igram. 



