EFFECTS OF FORESTS UPON CLIMATE : ST. HELENA, ETC. 303 



The important iufluence which the trees of the laurel tribe exert npon the mainte- 

 nance of springs of water, is well understood in this country, though the admirable 

 laws which have been devised for their preeervation are too much disregarded and 

 contravened. In one of the Canary Islands, the people still show the place where, at 

 the head of a deep valley, stood a fine, solitary til tree, which daily used to strain 

 a large quantity of water from the humid mist conveyed inland by the sea breeze. 

 The tree is mentioned by Cordeyro and subsequent writers, with the customary em- 

 bellishments of exaggeration and superstition ; but both the spring of water and the 

 tree are now gone, aud the mists, though they still remain, pass over unstrained of 

 their moisture. 



The aggregation of small particles of water from humid mists, then, we may regard 

 as a great source of water in a country like Madeira, where the moisture of the p'e- 

 vailiugwind is daily condensed upon the mountains; and such a manner of supply 

 must be common to many countries, although it is often unrecognized. 



St. Helena. 



This island bas been mentioned as affording; direct illustration of the 

 connection that exists between forests and rain -fall. When first discov- 

 ered in 1502, it had heavy forests. The introduction of goats, and other 

 causes, destroyed these woodlands, until the island was almost denuded. 

 The consequences were that in the records of the last century we find 

 accounts of repeated and almost periodical visitations of very severe 

 drought, occasioning various losses to cattle and crops. Toward the end 

 of the last century, however, the governor saw the need of strenuous 

 measures to restore vegetation. Nurseries were established, experienced 

 gardeners sent, and trees from all parts of the world were planted and 

 found to flourish. Prizes were given for the number of trees reared, 

 without regard to their character. The Finus pinaster was sown very 

 extensively, and several plantations of this still exist. The consequences 

 of this were described a few years since, as follows : 



For many years past, since the general growth of our trees, we have been preserved 

 from the scourge ; and droughts, such as vrere formerly recorded are now altogether 

 uukuowu. We have no means, however, of otherwise comparing the rain-fall of tho 

 two periods, as no tables, or even estimates of tho rain-fall can be had for the earlier 

 dates. Onr fall of rain now is equal to that of England, and is spread almost evenly 

 over the year. The showers fall more heavily in two or three months of the year. 

 But this period, though called on this accouut the rainy season, is in no way to be com- 

 pared to what is understood by an inter-troj)ical rainy season. 



But since the transfer of the island from the East India Company in 

 183G these plantations have been neglected, prizes for cultivation have 

 stopped, and, for the last thirty years at least, a score of trees have 

 been cut down to one planted.^ 



Island of Ascension. 



This island, some 7J miles long and G wide, was entirely barren when 

 first occupied in 1815, and so destitute of water that supplies were brought 

 from England and the Cape of Good Hope. According to a report made in. 

 1864, there were 29 acres of furze and shrubbery, and over 27 acres in 

 crops. The rain-fall has increased in proportion to the cultivation, and 

 from 10.18 inches in 1858, was 25.11 iu 1863, the increase in vegetation 

 being from 59,402 to 75,557 pounds. It grows forty kinds of trees, where 

 but one tree grew in 1843, owing to want of water. The water supply 



^Forests and Moisture, by John Croumbie Brown (1877), p. 117-125, which gives 

 extracts from correspondence in 1865 from his excellency H. R. Janisch, governor of 

 the island. Other authorities cited are Beatson's St. Helena, Emsmau's German trans- 

 l.ition of Foissac's work on Meteorology, in relation to cosmical phenomena (1859), 

 aud Blanqui, in a volume entitled Voyage en Bulgarie (1843). 



