Modification of Mixed-Conifer Forests by Ruminant Herbivores in the Blue Mountains Ecological Province

Secondary plant succession and the accumulation of biomass and nutrients were documented at seven ruminant exclosures in Abies and Pseudotsuga forests variously disturbed by logging, burning, and grass seeding. Long-term (25 or more years) foraging by Rocky Mountain mule deer (Odocolleus hemionus) and Rocky Mountain elk (Genius elaphus) suppressed the development of deciduous shrubs. Ruminant herbivores influenced vegetation to extents equal to those of the initial episodic disturbances. Food preferences of elk were linearly correlated with longterm development of plant taxa. Accumulations of understory and forest floor biomasses were greater inside exclosures than outside. Accumulations of nitrogen, phosphorus, calcium, magnesium, and potassium were greater inside exclosures than outside.Keywords: Abies, biomass, Bos, Cervus, cycling, disturbance, ecosystem, fire, forest, herbivory, logging, nutrients, Odocolleus, Ovis, productivity, Pseudotsuga, seeding, shrubs, site, succession, understory

Recovery of burned-reseeded and chemically treated oak-chapparral in Arizona

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Viability of Grass Seed After Long Uncontrolled Storage

In 1961, germination tests were made on seeds of 12 southwestern grass species collected between 1933 and 1939. Some seeds of vine-mesquite, silver beardgrass, curlymesquite, and Arizona cottontop remained viable, even though stored with no control of humidity or temperature.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Responses of desert grassland vegetation to mesquite removal and regrowth

The purpose of this study was to determine the long-term response of understory vegetation in the desert grassland of southeastern Arizona, USA, to removal and regrowth of mesquite Prosopis juliflora (Swartz) DC. var. velutina (Wooton) Sarg. trees. The study involved 3 treatments applied to mesquite in 1966; mesquite left intact (MI), mesquite removed (MR), and mesquite removed, sprouted, and regrown (MRS). Vegetation responses to 2 litter treatments, litter intact (LI) and litter removed (LR), also were examined. Cover of understory vegetation and juvenile mesquite ( 1.5 m height) were measured in canopy and open (intercanopy) locations. Major changes between 1967 and 1991 were increased cover of juvenile mesquite, shrubs, halfshrubs, bush muhly Muhlenbergia porteri Scribn., and Lehmann lovegrass Eragrostis lehmanniana Nees., and a decline in cover of Arizona cottontop Digitaria californica (Benth.) Chase, and plains bristlegrass Setaria macrostachya H.B.K. Arizona cottontop, plains bristlegrass, and bush muhly were more abundant in canopy locations; black grama Bouteloua eriopoda Torr. and Lehmann lovegrass were more abundant in open locations. Lehmann lovegrass cover was lowest in canopy locations of the mesquite intact treatment. Combination of the mesquite removed and sprouted and litter intact treatments favored increased cover development of native perennial grasses. Litter removal enhanced cover development of Lehmann lovegrass, most likely through increased amount of red light and increased soil temperature fluctuations. Low levels of understory cover (22% average) probably facilitated recruitment of mesquite and other woody plants. Our observation that the greatest cover of Arizona cottontop, plains bristlegrass, and bush muhly occurred in the canopy location of the mesquite intact treatment suggests a potential strategy for maintaining diversity of native perennial grasses. Mature mesquite should be examined as a refuge for native species.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Influence of western juniper development on distribution of soil and organic layer nutrients

The purpose of this study was to determine effects of invading western juniper (Juniperus occidentalis Hook.) into big sagebrush (Artemisia tridentata Nutt.)/bluebunch wheatgrass (Agropyron spicatum (Pursh) Scribn. and Smith (now Pseudoroegneria spicata)) ecosystems of central Oregon on spatial distribution of nutrients in organic and mineral soil layers. The organic layer and mineral soil from four layers (0-5, 5-15, 15-30, and 30+ cm), were collected beneath juniper trees of five size classes, and one area devoid of juniper on five replicated sites. Samples were taken at five distances (0 to 4 canopy radii) from tree boles into intercanopy areas. The organic layer and mineral soil were analyzed for organic carbon (Corg), total nitrogen (N), total phosphorus (P) and total sulfur (S); mineral soil was analyzed for exchangeable calcium (Caex), magnesium (Mgex) and potassium (Kex). Mass of the organic layer and amounts of organic layer nutrients increased with juniper size, and were higher under canopies than in intercanopy and no juniper areas. Concentrations of organic layer N, P, and S declined with distance from tree boles. Tree size, distance and soil layer interacted to affect concentrations of soil Corg, Kex, Caex and Mgex. Concentrations of soil N and S increased with tree size. Amounts of soil nutrients, except Corg, were not significantly influenced by tree size, but amounts of all soil nutrients, except S and Caex, were greater under juniper trees than intercanopy areas. Only Caex and Mgex appeared to have been lost from intercanopy soils compared to no juniper soilsKlemmedson and Tiedemann "Influence of western juniper development on distribution of soil and organic layer nutrients." Northwest Science. 2000; 74(1): 1-1

BOLE VOLUME GROWTH IN STEMS OF QUERCUS GAMBELII

Volume: 53Start Page: 162End Page: 16

SOIL AND VEGETATION DEVELOPMENT IN AN ABANDONED SHEEP CORRAL ON DEGRADED SUBALPINE RANGELAND

Volume: 54Start Page: 301End Page: 31

SOIL-VEGETATION RELATIONS OF RECOVERING SUBALPINE RANGE OF THE WASATCH PLATEAU

Volume: 58Start Page: 352End Page: 36