Carrying capacity of grazing ranges in southern Arizona . Rita Range Reserve. Ariz., showing where quadratcollections have been made and where hay has been cut. The small letters refer tocollections made from 1003 to 1908. inclusive, the unaccented letters indicating springand the accented letters fall collections. Likewise, the small figures refer to col-lections made from 1912 to 1914, inclusive, the figures without circles indicating collec-tions made in the spring and figures in circles fall collections. The shaded areas showwhere hay has been cut. The capital letters are introduced for co
Carrying capacity of grazing ranges in southern Arizona . Rita Range Reserve. Ariz., showing where quadratcollections have been made and where hay has been cut. The small letters refer tocollections made from 1003 to 1908. inclusive, the unaccented letters indicating springand the accented letters fall collections. Likewise, the small figures refer to col-lections made from 1912 to 1914, inclusive, the figures without circles indicating collec-tions made in the spring and figures in circles fall collections. The shaded areas showwhere hay has been cut. The capital letters are introduced for convenience in reference. servations and study made while riding over the reserve in all di-rections twice a year for the past three years. It is not a stricthecological map, though some of its areas approximate the plant zonesof the region. There is no doubt that the natural distribution GEAZING EANGES I^ SOUTHEEN AEIZONA. 5 areas of certain species, and probably of the associations, had beenmuch displaced by the previous grazing conditions to which the. 5 ED ^ nn 6 B 4. C3 8E39 Fig. 3.—Map of the Santa Rita Range Reserve, Ariz., showing the present distribution of theprincipal forage-plant associations : No. 1, The six-weeks-grass association. No. 2. Theblack-grama association. No. 3. The crowfoot-grama association. No. 4. The needle-grass association. No. 5. The oak belt. No. 6. The forested area. Those parts ofthe reserve upon which the mesquite (Prosopis velutina), the cats-claw (Acaci-a greggii),and other shrubs or low trees occur, more or loss abundantly, are indicated by dots(No. 7) on the map. In the same way, the crosses (No. 8) and the check marks(No. 9) show where the tree cactus {Opuniia spinosior) and the cholla {OpuntiafuUjida) are important members of the plant associations (PI. I, fig. 2). region had been subjected, and that under the protection of the fencethese plants have been and are still readjusting themselves to thenormal ecologic conditions. Maps of thi
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Keywords: ., bookcentury1900, bookdecade1910, bookidcar, booksubjectrangelands
