346 



Yearbook of Agriculture 1949 



The area occupied by the type, due 

 to low precipitation and heavy evap- 

 oration, is not a high-yielding water- 

 shed. The runoff per acre is lower than 

 that for the saw-timber type, where 

 total precipitation is greater and the 

 winter precipitation is in the form of 

 snow. Although the yield per unit of 

 area is low, the total yield from the 

 large area is of material value, espe- 

 cially because most farming is done 

 under irrigation and water in the 

 Southwest is most important. 



The pinyon- juniper forest furnishes 

 grazing for domestic livestock and 

 game. Animals that spend the sum- 

 mer at higher elevations come in win- 

 ter to the lower ground, where snows 

 are not so deep as to cover the forage. 

 Some livestock and game use the for- 

 age yearlong, but if such grazing is not 

 properly regulated, the grass and the 

 shrub cover essential to protect the 

 soils from erosion is seriously reduced. 

 Winter use alone is best suited to main- 

 taining normal cover. The light stand 

 of relatively sparse foliage trees of the 

 type produces much less forest litter 

 than do the saw-timber forests at high- 

 er elevations. The litter is effective in 

 soil protection and in reducing run- 

 off, but the grass and shrubs in the 

 intervening nonforested areas must 

 be maintained to insure soil stability. 

 When this is overused, sheet and gully 

 erosion result. The pinyon- juniper 

 type, because of the heavy use by live- 

 stock and game, contributes appre- 

 ciable quantities of silt to streams. 



ONLY DURING the past 40 years, 

 since the creation of the national for- 

 ests, has any positive action been taken 

 to give protection to the forest and 

 to direct wood harvests in ways that 

 would insure continuous yields of ben- 

 efits and products. Fires once denuded 

 large areas. The pinyon is susceptible 

 to bark beetle attacks, and considerable 

 losses have resulted from this cause. 

 Mistletoe causes material losses in ma- 

 ture juniper. Destructively heavy cut- 

 ting has practically denuded some 

 areas; on others, cutting has severely 



reduced the stands. Recovery is slow 

 The seeds of the pinyon and juni- 

 pers are heavy and normally fall close 

 to the parent tree. The spread of the 

 type is slow unless the seeds can be 

 spread by other means for example, 

 by birds, game, and domestic stock. 

 The passage of the seeds through the 

 digestive tract materially aids germi- 

 nation, and this method of seed disper- 

 sal by animals is important in aiding 

 the extension of the type. This ex- 

 tension is especially noticeable along 

 trails used by sheep in their travels 

 from winter to summer ranges and re- 

 turn, and in the large natural open- 

 ings, locally called parks, within the 

 range of the species, and around the 

 edges of the type. 



After the national forests were estab- 

 lished, adequate fire protection was 

 given pinyon-juniper forests. Better 

 roads were built and made easier the 

 harvest of fuel and posts. Positive ac- 

 tion was taken to initiate a system of 

 cutting by which only trees above a 

 fixed diameter or dead or diseased 

 trees could be harvested. The aim was 

 to insure an adequate seed supply and 

 sufficient stand to maintain forest con- 

 ditions. Since yield and prices of the 

 product are low, any system followed 

 must be selected with the end of bal- 

 ancing costs and results. Growth is 

 slow probably not more than a half 

 inch in diameter a decade. Virgin 

 stands approximate 200 years of age. 

 The volume per acre measured in 

 cords varies greatly, being lowest at the 

 lower edge of the type where yields will 

 not exceed 2 to 4 cords; better stands 

 often yield 25 cords to the acre. The 

 slow growth and low yields are the 

 result of low precipitation. 



In assessing the future of this forest 

 area, of which some 20 percent is in 

 national forests, one should remember 

 that some of it has been heavily cut 

 and has little chance for another crop 

 for a long time; some of it has been 

 lightly cut; some has only been high- 

 graded for post material. Except for 

 limited areas in the rather inaccessible 

 places, only minor areas of so-called 



