Clare Island Survey — Tree- Growth. 



9 25 



in March, 1914, and ranch evidence of the same sort of thing could be seen 

 between Mulranny and Tnllaghan Bay, one of the most wind-swept parts of 

 the Belmullet area. 



The only explanation that can be found of this unusual occurrence is 

 the higher autumn temperature of 1913 in that part of Ireland. The 

 Blacksod records of the monthly means, as given in the Meteorological Office 

 Reports, show the following differences from the average : — 





Mean Temperature. 



Kainfall in Inches. 





+ 



- 



+ 



- 



July, . . 



- 



1-2° 



— 



1-19 



August, 



02° 



- 



- 



3-02 



September, 



0-6° 



- 



•45 



- 



October, . 



1-9° 



- 



\-ld 



- 



November, 



2-6° 



- 



1-69 



- 



December, 



1-5° 



- 



- 



•67 



Net, + . 



+ 5-6° 



- 



- 



- 1-48 



If the four months July to October only are taken, an increase of T5 is 

 shown in temperature and a decrease of 2'5 in rainfall, the last three months 

 in the year being responsible for the high gain in the former. It is not. 

 probable that the comparatively small difference in rainfall had any 

 appreciable effect, and the higher temperature appears to be the only 

 important difference from the normal in 1913, as winds were as strong and 

 frequent as in 1912, although perhaps rather below the average on the whole. 



If similar conditions to the above prevailed during a series of years, it 

 is quite probable that tree-growth in the west might show quite a different 

 development. As it is, the above proves the comparatively slight climatic 

 change that would be necessary to restore the conditions which probably 

 existed during the climatic optimum in the west of Ireland, although the higher 

 temperatures possibly occurred earlier in the season than those of 1913. 



Relation of Clake Island Forest Flora to that of Mainland. 



The position of Clare Island with regard to the mainland and the existing 

 distribution of trees on the latter raise certain questions which are of 

 special interest, as they afford circumstantial evidence of the antiquity of the 

 island flora. Clare Island is at present separated from the mainland by two 



PROC. R.I. A., VOL. XXXI, P 9 



