1S4 FLORIDA GEOLOGICAL SL'RNEY SLXTH ANNUAL REPORT. 



the year, but the four warmest niuiuhs get a httle mure than their 

 share. 



Taking- the area as a whole, the sahent features of its chmate. 

 as compared with that of Georgia and Alabama, are the mild dry 

 winters and wet summers. The copious suminer rains, while they 

 make droughts rare, seem to be largely responsible for the pre- 

 valence of sandy soils and evergreen trees in Florida, for the rain 

 tends to leach out the clay, lime, potash, etc.,* and leave the sand, 

 and evergreens seem to be especially characteristic of soils poor in 

 clay and potash, as already noted. t 



Vegetation types. No systematic study of vegetation types is 

 attempted here, as explained on page 175, but under each region a 

 few of the leading types are mentioned. Special reference is made 

 to the frecjuency of fire, which varies greatly in different regions and 

 in different types of vegetation. Outside of the long-leaf pine 

 regions of the South (and somewhat similar forests in a few other 

 parts of the world), forest fires are comparatively infrecjuent, and 

 have been commonly regarded as regrettable accidents. But in 

 Florida it is evident that fire is a part of Nature's program. The 

 pine forests which cover the greater part of the state everywhere 

 bear the marks of fire, which visits any one spot perhaps once in 

 two years, on the a^•erage. In pre-historic times the fires must have 

 been started mostly by lightning, hut now they are mostly of human 

 origin. Although fires are more numerous at the present time than 

 thev were originally, the area over which each one can spread is 

 limited by roads, clearings, and other artificial barriers, so 

 that the frecjuencv of fire at any one point may not have changed 

 much. Long-leaf pine is injured less by fire than almost any other 

 tree, so that the effect of repeated fires is to give this tree the 

 advantage over all its associates. 



It is reasonably certain that if fire were kept out of a l(Mig-leaf 



*Cherrapongee, in Assam, is the wettest known place in the world, having 

 an annual rainfall of over 600 inches;' and travelers who have been there 

 report the surrounding country as practically barren. No doubt if the soil 

 is not all washed away it must be pretty thoroughly leached of plant food. 



tSome of the probable relations of seasonal distribution of rainfall to the 

 character of the soil have been discussed briefly by the writer in Bull. Torrey 

 Bat. Club 37:415-416. 1910: 40:395-396. 1913: Torreya 13:141. 1913; Geol. 

 Surv. Ala., Monog. 8-19, 24, 36. 1913. For notes on the relation of evergreens 

 to soils see footnote on pages 175-177 of this report. 



