November io, ^904] 



NA TURE 



33 



is situated forms a kind of plateau, traversed by 

 numerous deep canons and dotted by several hundred 



This unsatisfactory condition is attributable to the 

 numerous fires which have occurred in this region 

 within the last 200 years. In addition to the destruc- 

 tion caused by fire, careless cutting and grazing have 

 done much damage in the reserve. 



The reproductive capacity of the yellow pine in the 

 reserve is extremely small — there being a great deficit 

 in seedling and sapling growth. There has apparently 

 been a complete cessation of reproduction over large 

 areas during the past twenty or twenty-five years. 

 This low reproductive capacity is attributed to various 

 causes — some depending on the operation of natural 

 agencies, others on human intervention. The grazing 

 value of the reserve was at one time very great. .\s 

 the gramineous flora of the region is a rich one, there 

 was formerly a luxuriant growth of grass, but owing 

 to the persistent and excessive pasturing, especially 

 by sheep, the turf-forming grasses were reduced in 

 size and vegetative activity, which led to various 

 changes in the character of the subsequent vegetation. 

 What was formerly pasture land is now covered by 

 exuberant growths of various low desert shrubs and 

 herbaceous Compositae, particularly species of sun- 

 flowers. 



The agricultural value of the region is not great, 

 there being only some 2500 acres under the plough, 

 and these occur in the now dry beds of what were 

 formerly Stone-man and Mormon lakes, or at the foot 

 of ridges where local areas of seepage exist. The crops 

 consist of oats, wheat, and potatoes. There is no fruit 

 culture in this region. This reserve, like the others, 

 is subdivided into townships and ranges, the detailed 

 descriptions of which are included in the report. At 

 the end we have a very useful summary, showing in 

 tabular form a classification of lands in the reserve by 

 townships. The maps and photographic illustrations 

 are of the same high standard as those which 

 accompany the other reports of this series. 



The Black Mesa Forest Reserve comprises an area 

 of 2786 square miles, made up as follows : 



Squ 



volcanic cones, which vary in height from 100 feet to 



1000 feet. The soil is various, but gravelly loam is 



the prevailing type. On the 



slopes of the volcanic cones and 



ridges in their neighbourhood 



scoriaceous soils prevail. The 



water-retaining capacity of the 



latter class of soil is not very 



great. The loamy soils are best 



adapted for forest growth. As 



regards drainage, the visible run 



of permanent surface flow is 



small. Most of the precipitation 



sinks either within the reserve or 



in the desert or semi-desert tracks 



which border it. 



Electric storms do considerable 

 damage to the standing crop in 

 the reserves, and it is estimated 

 that in some places as manv as 

 5 per cent, of the trees have been 

 struck and killed by lightning. 

 There are twelve coniferous 

 species in the reserve, but the 

 yellow pine predominates, pro- 

 ducing more than 99 per cent, of 

 the merchantable timber, and 

 forming 90 per cent, of the total 

 forest. x^bout the same number 

 of broad-leaved species occur, but 

 a complete list of them is not 



available. .\11 over the reserve the stands of yellow 

 pine do not carry an average crop of more than 40 per 

 cent, of the timber they are capable of producing. 



NO. 1828, VOL. 71] 



Squ 



2.— Largi 



■th of Alligator Ju 



k very striking feature of the report is the de- 

 crease in the water supply due to successive seasons 

 of drought, which have practically destroyed the value 



