PLANT MORPHOGENESIS FOR SCIENTIFIC MANAGEMENT OF RANGE RESOURCES 



141 



indicated that they still have a long way to go to 

 double the capacity of the Harvey Valley allot- 

 ment. In 1967, the livestock permittee was 

 granted a length of grazing season increase with 

 no change in permitted numbers. When the trial 

 at Harvey Valley was established, it was ex- 

 pected that the grazing capacity would be dou- 

 bled in 20 years (15). 



Conifer Forest Ranges 



Pinus ponderosa Dougl. ex Lawson forests are 

 the most important forest grazing area in the 

 Western United States. In Washington and Ore- 

 gon, approximately 10 million ha. of forest graz- 

 ing land furnishes summer forage for 250,000 

 cattle and nearly as many sheep (34)- Effects of 

 cattle grazing on herbage production were in- 

 vestigated 1954-66 on the Starkey Experimental 

 Forest and Range near La Grande, Oreg. Ele- 

 vations vary between 1,000 and 1,500 m. Annual 

 precipitation averages 54 cm. Summer is the 

 driest season. Open stands of Pinus and Pseudot- 

 suga memiesii (Mirb.) Franco have an under- 

 story of Car ex geyeri Boott., Calamagrostis ru- 

 bescens Buckl., and a variety of forbs. Principal 

 species in intermingled grassland openings are 

 Agropyron spicatum (Pursh) Scribn. & Smith, 

 Poa secunda, and Danthonia spicata (L.) Beau v. 

 ex. Roem. & Schult. 



Deferred-rotation and season-long grazing at 

 three intensities were compared (34). The graz- 

 ing period was about June 15 to October 15. Un- 

 der deferred-rotation, the cattle were placed in 

 half of the range for 2 months and then moved 

 to the other half. The following year, the early 

 and late pattern was reversed. Systems of graz- 

 ing did not cause significant difference in produc- 

 tion of any major plant group or species in the 

 grassland type. In the forest type, heavy stock- 

 ing reduced production of Carex from 455 kg./ 

 ha. to 227 kg./ha. Carex was very susceptible to 

 grazing. It retained its production during the 12- 

 year period only with light stocking in the de- 

 ferred-rotation system. There was essentially no 

 difference in reduction of Carex production under 

 deferred-rotation and season-long grazing with 

 moderate and heavy stocking. Skovlin and Har- 

 ris (34) suggested that herbaceous forest vege- 

 tation may have been adversely affected by gen- 

 eral reduction in May-July precipitation from 



15 cm. in 1957 to less than 10 cm. in 1966. Initial 

 intensive management practices such as fencing, 

 water development, and salting were effective in 

 increasing cattle use in the forest type (8). 



Smith et al. (35) compared moderate rotation, 

 heavy rotation, and moderate season-long grazing 

 in the Big Horn Mountains near Burgess Jun- 

 tion, AVyoming. The elevation is 2,440 m. The ma- 

 jor forage species is Festuca idahoensis, but 

 there is a variety of herbaceous and browse spe- 

 cies. The average annual precipitation is 79 cm. ; 

 about 40 percent occurs April-June. Frost and 

 snow may occur at any time. The grazing season 

 is June 20-September 20. In the rotation units, 

 steers were moved among the thi-ee divisions at 

 about monthly intervals. The rotation was such 

 that the same division was not grazed at the 

 same time in consecutive years. The study cov- 

 ered the 1959-64 period. There was no significant 

 difference in daily gain between moderately 

 stocked units (about 0.95 kg.). The daily gain 

 on the heavy rotation unit averaged 0.82 kg. On 

 soils of granitic origin, production of Festuca 

 was maintained equally well on the three treat- 

 ments. On soils derived from sedimentary de- 

 posits, the abundance of Festuca declined within 

 the heavy rotation unit. Cover and production of 

 Festuca was best maintained with season-long 

 grazing. However, it generally was not utilized 

 until mid-August on the season-long unit ; where- 

 as, it was moderately utilized as early as late 

 July in the rotation units. In that area, Festuca 

 makes little regrowth in the year it is grazed 

 regardless of the time or amount of herbage re- 

 moval (35). During 1961-63, use of Festuca aver- 

 aged from 20 to 43 percent for the three grazing 

 treatments. However, production declined during 

 the study even though precipitation during the 

 latter part of the study was above average. From 

 the evidence presented, it appears that Festuca 

 is not well adapted to grazing at the rate termed 

 moderate at Burgess Junction. 



Intermountain Shrub Region 



Season-long grazing was compared with de- 

 ferred-rotation grazing at the Squaw-Butte Ex- 

 periment Station in southeastern Oregon during 

 1938-18 (19). The elevation is 1,375 m. and the 

 average annual precipitation is 30 cm. Two- 

 thirds of the precipitation occurs as snow in the 



