240 Studies in Forestry [CHAP. xi. 



traceable. Formed by sowing on old arable land, its growth and 

 development were good at first; but about its fortieth year the soil 

 became overrun with whortleberry, the increment of the crop 

 fell considerably, and its appearance was unpromising. Without 

 any thinning being made, beech-mast was sown out in 1840 

 for underwood, to which during 1844-1847 a heavy thinning 

 or partial clearance succeeded with simultaneous underplanting 

 (at forty-six years of age). Light thinnings were afterwards 

 made in 1853, 1859, 1873, and finally in 1887, when about 

 eighty stems per acre were removed, leaving about 300 per 

 acre on the average, which had formed canopy again. The 

 effect of the first thinning was hardly sufficient to affect the 

 breadth of the annual rings or the general shape of the bole ; 

 but it was still traceable in the predominant and dominant 

 stems till the third and fourth decades. 



The measurements made on sample stems showed that the 

 increment in height diminished after the heavy thinning or 

 partial clearance, but eventually attained its former level, and 

 in some cases exceeded this. That is to say, the energy of 

 growth in height was diverted and utilized in the coronal 

 expansion, whilst it was re-directed into its original channel 

 when the crowns approached again to form close canopy. 



Without giving any of the statistics and measurements 

 recorded which can only be exhibited, for each series of in- 

 vestigations, in an extensive tabular form that might be out of 

 place here the following are the results arrived at, as published 

 in a pamphlet by Dr. Kast, Lecturer on Forestry in Munich 

 University l . When crops of light-demanding forest trees are 

 underplanted, and the underwood begins to form close canopy, 

 the effect is to produce a diminution in the breadth of the 

 annual rings near the base of the stem, but this only affects the 

 upper portion of the bole either to a less extent, or not at all, 

 whilst the total annual increment is not always decreased. 

 If any such decrease be considerable, it is probably due to 

 1 Ueber den Unterbau und seine wirthschaftliche Bedeutung, 1889. 



