158 PRUNING FIR-TRKES. 



performing the same, and regulating the distance of the 

 plants in Fir Plantations. 



Fig. 1. Section A. shows a dead knot and progress in the 

 growth of the tree, having 19 years of growth below the 

 bough, and 18 years above it. From the regular course of 

 nature, as shown by this section, it is evident, this bough or 

 knot must have existed as long as the upper part of the tree, 

 namely, 18 years. For the first three years the growth and 

 Bough e oo accumu i a tion of the bough proceeded regularly with the 

 tree; but about that time (now 15 years ago) the bough 

 must have been distantly cut off, thereby preventing its re- 

 gular increase in the part left remaining; for 6 years after 

 cutting oft" it appears to have barely existed, and after that 

 ceased to exist at all but as a dead bough. Since it became 

 so, 9 years of accumulation have taken place on the trunk of 

 the tree, thereby gradually enclosing a part of the dead 

 bough, which part so enclosed is what by joiners is properly 

 called a dead knot; the boughs that exist and are enclosed 

 whilst living, are the live knots, and these the tree will pro- 

 duce either as the bough may be distant or close cut from 

 the tree. From this specimen may be determined, that if 

 the bough had been cut close to the tree at four years 

 growth, there would now have been sound clean wood over it 

 to the outside : or when it was- cut,* if it had been taken off 

 at 0, sound clean wood would have formed over it to the 

 outside. 



N. B. In all th p specimens this mark is affixed to point 

 out the proper place for cutting off, and is so placed as to 

 allow for thickness of bark at the time it should have been 

 cut. 



Other in- Section B. shows a striking instance of the impropriety 



stances of bad f leaving the smallest bough cut at a distance from the 

 tree; this bough was cut off and became stagnant at 2 

 years growth, notwithstanding which it was 14 years before 

 the wood on the trunk accumulated to the end of the dead 

 knot. 



Had this bough been cut at ®, the knot as far as that 

 would have been firmly united with the tree, and above it all 

 sound clean wood. 



Fier. 2. 



