396 PLANTS, SEEDS, AND CURRENTS 



forty feet. The Erica trees evidently need the protection of a wood 

 to attain their maximum size. Though a few of them in these pre- 

 serves must have measured between thirty and thirty-five feet, it was 

 apparent from the number of leaning and fallen trees that this was 

 their limit. 



It does not seem, however, that the present Juniper trees anywhere 

 approach the size attributed to the " cedros " of the original forests. 

 On Pico a height of fifteen or sixteen feet and a diameter of fifteen 

 to eighteen inches (in very rare cases twenty inches) represent my 

 maximum measurements. Rarely does the Azorean Juniper grow 

 straight, the trunk being twisted and bent. It is likely that the 

 finest specimens exist on the uplands of San Jorge. Judging from 

 a photograph kindly taken in my interest by Colonel Chaves, they 

 might there attain a height of eighteen or twenty feet. Mr. Ogilvie- 

 Grant mentions the " grand old Juniper trees " in the higher levels 

 of the same island (Novitates Zoologicce, XII., 1905). 



The Causes of the Destruction of the Original Forests. — 

 That the volcanic eruptions of early times played an important part 

 in the destruction of forests in the Azores is highly probable. The 

 old timber trees, as before described, are now found buried beneath 

 their ejectamenta. In the early part of the occupation by man, 

 namely, in the fifteenth and sixteenth centuries, the devastation 

 of the forests from this cause must have been tremendous, and it is 

 likely that the older outbreaks produced similar results. Since 

 pumiceous tuffs strew the surface of San Miguel and are often exposed 

 in sections a hundred feet in thickness, both in the high and in the 

 low levels, we cannot help reflecting that the land-surface at such 

 times must have been largely deprived of its covering of vegetation. 

 The outbreak that occurred in the valley of Furnas in 1630 well 

 illustrates what must have often taken place before. For three 

 days and nights the ashes fell over all the island of San Miguel, 

 covering the surface to a depth ranging from seven to twenty feet, 

 and in many places destroying all the vegetation (Walker, pp. 61, 

 214). Even greater desolation must have resulted from the eruption 

 of 1445, when the highest eminence of the island at its western end 

 was destroyed, leaving the great crater of the Seven Cities as its 

 mark (Ibid., pp. 51, 57, etc.). The adjacent seas were covered with 

 fields of floating pumice and immense trunks of trees, through which 

 Cabral, the Portuguese navigator, made his way when approaching 

 the island. It is probable that in the relatively recent activity of the 

 volcanic forces in the Azores we have an explanation of the curious 

 fact referred to in a later page of this chapter, that of the three 

 Macaronesian groups, the Azorean, the Madeiran, and the Canarian, 

 it is the group that is farthest from the mainland, namely, the Azores, 

 that displays the least evidence of differentiation in its flora. 



Yet it is likely that the plant world would have of itself regained 

 much of its hold on the Azores, if it had not been for the arrival 

 of the European. Man and his animals have completed the destruc- 

 tion of the original forests. In fact, Colonel Chaves, whose opinion 

 would carry the greatest weight, seeks for the exclusive factor in 

 the disappearance of the forests in " the destruction made by the 

 inhabitants for constructions, fire, and exportation " (letter cited). 



