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 11 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. 
For 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. Inthe 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 
