spection of the plantings, though, reveals no 

 regeneration. 



Baker and Korstian reported that distri- 

 bution of rainfall during the summer months 

 in these brush areas in Utah "is notably differ- 

 ent from that either to the north or south;" 

 also that "deficiencies in July and August pre- 

 cipitation, combined with the fact that the 

 rainfall usually culminated in August shortly 

 before the early autumn frosts occur, make it 

 impossible for the species to reproduce." 

 They noted further that "the generally calcar- 

 eous, heavy, fine-grained soils of the brush 

 lands are prevailingly unsuited for western 

 yellow pine." They were convinced that dis- 

 tribution of rainfall primarily determines the 

 "pineless belt" and that details of its bound- 

 aries resulted chiefly from local differences in 

 soils. The intense competition from the estab- 

 lished brush cover was another factor limiting 

 good growth of ponderosa pine. 



F. S. Baker also did a great amount of 

 work on aspen. Sampson (1919a) did some 

 early work on aspen silviculture but it was 

 mainly incidental to the study of the effect of 

 grazing upon aspen reproduction. Baker's 

 (1925a) major publication on the subject was 

 the first to describe the phenology, growth, 

 form, root systems, and the climatic, mois- 

 ture, and soil requirements of aspen in detail. 

 It was also the first comprehensive work on 

 growth, yield, and management of aspen in 

 the West. A major part of the publication was 

 directed to the rate of growth and yield of as- 

 pen on different sites as a basis for manage- 

 ment. 



As part of his study, Baker established an 

 elaborate set of permanent plots to determine 

 if aspen timber production could be increased 

 by thinning. In general, he found that thin- 

 ning increased the production of wood in the 

 form of sprouts and young trees but did not 

 appreciably increase growth rates of larger 

 trees. The detailed records on these perma- 

 nent plots are invaluable historical base data 

 on the ecology of aspen and are continuing to 

 be used in current research. In 1970, Kimball 

 Harper of the University of Utah and Robert 

 Pfister of the Intermountain Station remeas- 

 ured the trees on these plots to determine the 



rates of growth and the mortality of the aspen 

 trees. 



Baker and other early workers recognized 

 that the aspen type is perpetuated by fire and, 

 because of prevalent natural fires, aspen has 

 occupied many sites for very long periods of 

 time. In the absence of fire, aspen is suc- 

 ceeded by conifers. Baker discussed the rela- 

 tive values of aspen and conifer on the same 

 site. Based on the economics of the time he 

 concluded that income from aspen would be 

 lower than from conifer and that "there can 

 be no point, therefore, in trying to maintain 

 an aspen management type." In recent years 

 the validity of this conclusion has been ques- 

 tioned by many who feel that the multiple 

 benefits of aspen, including grazing for live- 

 stock and game, habitat for many birds and 

 small mammals, fire resistance, and esthetics, 

 outweigh the value of conifers for timber 

 production on many sites. 



Korstian, like many other close observers 

 of plant life in mountainous areas of the West, 

 noted the, striking zonation of vegetation in a 

 regular series of altitudinal belts in Ephraim 

 Canyon and elsewhere. This altitudinal zona- 

 tion, he believed, is important to the silvicul- 

 turist and to the range management specialist 

 because many of the problems of the growth 

 and regeneration of forests and the mainte- 

 nance of range can be solved best through 

 determination of the soil and climatic require- 

 ments of the different species in each zone, a 

 point well demonstrated by the ponderosa 

 pine study just described. In reforestation, 

 Korstian (1924b) wrote that success depends 

 on knowing the causes of successful growth 

 and establishment of individual species and 

 likewise knowing the causes of failure or par- 

 tial failure of other species in the same en- 

 vironment. Since the problem appeared to be 

 based on moisture requirements and availabil- 

 ity, he launched a study of the density of cell 

 sap in a variety of plants, including trees, 

 found in several altitudinal zones from 4,500 

 feet to the summit of the Wasatch Mountains. 

 This study, he believed, had implications for 

 both silviculture and range management. 

 However, despite the considerable detailed 

 work, its results never were put to much prac- 

 tical application. 



34 



