30 CLIMATIC CYCLES AND TREE-GROWTH. 



moisture. The trees had formed a border to a little plot of cultivated 

 land with a southwesterly exposure. The average age was 54 years. 

 The rings were all extremely plain, averaging 2 to 4 mm. in size, and 

 cross-identification was everywhere perfect. Of the 50 or 60 rings, 

 about 10 had marked characteristics and were easily recognized in 

 nearly every section. It was noted that a few sections had numerous 

 rings more sharply defined on the summer side of the dense red portion 

 than on the usual winter edge. One of the 11 sections is shown in 

 plate 3, A. 



The appendix contains a table of mean tree-growths of the 1 1 British 

 sections; the years 1859 to 1863 inclusive show means of 6 trees only, 

 as some did not extend back that far ; of these, 2 had their centers about 

 1858, 2 in 1857, and 2 in 1855. The owner 'of the land informed me 

 that the trees had all been planted at the same time, and therefore this 

 apparent discrepancy may be due to sections cut at different heights 

 above the ground. These means are plotted in figure 8. 



Fbr ready comparison it seemed desirable to standardize this British 

 curve as well as each of the other European curves. Each curve is 

 therefore corrected for changing rate of growth with age and also very 

 slightly smoothed to get rid of the confusing effect of the 2-year "see- 

 saw " described later. In the present group, after careful consideration, 

 the standardizing line follows the tree-growth through a uniform curve 

 in the earlier years and becomes straight in the later years. Percentage 

 departures from this mean standard line give the standardized curve. 

 These percentage departures smoothed by Hann's formula will be 

 found plotted in figure 23, together with similar curves from the other 

 European groups. 







OUTER COAST OF NORWAY GROUP. 



On the advice of Dr. H. H. Jelstrup of Christiania, I visited the 

 Forest School of Sopteland, a small place located about 18 miles south 

 of Bergen, near latitude 60. The elevation is but little above sea- 

 level, and irregular intervening hills give slight protection from the 

 North Sea storms. This group of 10 Pinus silvestris sections was 

 collected on January 3, 1913, from logs in the yard of the Forest School. 

 The logs had been cut within a week or two in Os, 12 miles to the 

 south, on an exposed part of the coast and probably close to sea-level. 

 Os is on the north shore of one of the larger inlets entering on the north 

 side of Hardanger Fjord. 



The average diameter was 6 to 8 inches and the average date of the 

 center was about 1840, but one extended back to about 1800 and 

 another to 1700. The average size of rings was about 1.25 mm. The 

 group cross-identified extremely well and on a preliminary inspection 

 seemed to show somewhat rhythmic variations in growth. In these 



