126 



T. H. BLANK AND J. S. ASH 



Table IV. Average daily hours of sunshine, number of * wet* days and average 

 rainfall {'wet' days) and young/ old ratios, 1949-59 



Year 

 1949 

 1950 

 1951 

 1952 



1953 

 1954 

 1955 

 1956 



1957 

 1958 

 1959 



Average 

 daily sunshine 

 June and July 



(hrs) 



9-04 



7-62 



7-65 



6-67 



6-20 



4-89 



7*22 



5-54 

 7-67 

 5-70 

 8-o6 



Wet* days 

 June and July 

 8 

 27 

 17 

 17 

 35 

 32 

 14 

 25 

 28 

 30 

 21 



Average rain 



per wet days 



June and July 



(mm) 



4-5 

 4-9 

 2-5 

 2-7 



3-5 

 4-6 

 6-8 

 3-6 

 5-0 

 4-2 

 2-6 



* Wet =0*2 mm or more. 



YjO ratio 



the critical months of June and July may be obtained by comparing survival 

 rates on similar areas that have experienced different weather conditions. In 

 1949 in the south of England the weather during June and July was dry and 



4-0 



3-0 



2-0 - 



1-0 



1950 1951 1952 1953 



Fig. 3. — Production rate and June-July weather. 

 (The width of the colunms represents average rainfall per wet day — see Table IV). 



