climate 43 



offshoot of a winter continental anticyclone, the weather may be very 

 cold. 



These data, or the conditions they represent, are significant for plant life 

 and agricultural practice. The rainfall, as we have seen, is low. The results 

 of deficiency and drought would be more apparent than they are, but for 

 the high water table of much of the neighbourhood and for the prevalence 

 of soils with a high capacity to hold water. Where, as in Breckland, the 

 soil is porous and non-retentive the rainfall deficiency is accentuated.^ Thus 

 because of the dry conditions, plants of the oceanic west may fail or grow 

 poorly. Among the planted conifers in and around Cambridge only the 

 xerophytic pines do at all well: spruces, hendocks, silver firs do badly. 



On the other hand, flooding may occur, and the floods of the early 

 months of 1937 ^^^ still fresh in the memory. They were due to an excep- 

 tional run of five very wet months, January to May, when the water 

 draining into the low Fenland depression found its normal flow to the sea 

 checked by a combination of wind and tide.^ 



Again, although the neighbourhood of Cambridge is an area of inten- 

 sive cultivation, the low temperatures of winter preclude competition 

 with the milder south-west in the production of spring flowers. The 

 extension into spring of cold wintry conditions and the frequency of cold 

 winds and recurrent spring frosts until the beguining of June mean the 

 crippling of frost-sensitive species of plants and in agricultural practice 

 inability to grow early potatoes. Fruit-tree blossom, too, is often severely 

 damaged. On the other hand, the greater number of hours of sunshine 

 allows a proper maturation of wheat, and the relatively high number of 

 hours of sunshine during September doubtless contributes to the percentage 

 of sugar in sugar beet. For native plants, in particular for the "continental " 

 element in our flora, sunsliine is critical for the ripening of seed.^ 



' See p. 208 below. * See p. 193 below. 



5 See A. S. Watt, "Studies in the Ecology of Breckland. I. Climate, Soil and 

 Vegetation", Jo»r. Ecol. xxiv, 117 (1936). 



