• WOOD PRODUCTS VALUE
• IMPORTANCE TO LIVESTOCK AND WILDLIFE
• PALATABILITY
• NUTRITIONAL VALUE
• COVER VALUE
• VALUE FOR REHABILITATION OF DISTURBED SITES
• OTHER USES AND VALUES
• MANAGEMENT CONSIDERATIONS

WOOD PRODUCTS VALUE:

IMPORTANCE TO LIVESTOCK AND WILDLIFE:

Pinyon mice, deer mice, woodrats, squirrels, chipmunks, deer, black bears, and desert bighorn sheep eat singleleaf pinyon seeds [23], as do scrub, Steller's, and pinyon jays and Clark's nutcrackers [64,122,123]. Many of these animals cache seeds for winter use and are critical for regeneration of singleleaf pinyon [35,123,180,211]. Although it is not favored, mule deer eat pinyon foliage [121,124], using the foliage moderately in winter, spring, and summer [117]. Singleleaf pinyon comprised 1 to 2% of the winter diet of pronghorn in Utah, while cattle and domestic sheep did not use it [183]. Cows may feed on pinyon in the winter, and it is thought that this can cause them to abort [121]. The inner bark is a major food of porcupines, and is also eaten by squirrels, raccoons, rabbits, ringtails, coyotes, and gray foxes [182], as well as the larvae of the mountain pine beetle and the fungus causing pinyon blister rust [121]. Limbs are attacked by pinyon dwarf-mistletoe (Arceuthobium divaricatum). The pitch is a staple food of pitch midges and is used by Dianthidium bees to build their nests. Sawflies feed on needles and pollen. Gall midges live in the needles by causing 2-needle fascicles to develop and living in the fascicle crotch [121,124].

PALATABILITY:

NUTRITIONAL VALUE:

COVER VALUE:

VALUE FOR REHABILITATION OF DISTURBED SITES:

OTHER USES AND VALUES:

MANAGEMENT CONSIDERATIONS:

Singleleaf pinyon can be managed for tree products such as fuel, fenceposts, resins, and pine nuts. Production of these resources requires healthy functioning of whole ecosystems, providing economic incentive for sustainable ecological practices. Management of woodlands for nut production will yield 100 times more income than will management for livestock forage, and the 2 can both be done on the same land and not interfere with one another [110]. Fisher and others [72] give management suggestions for improving nut crops in pinyon.

Some authors report no appreciable increase in spatial distribution of singleleaf pinyon in California [136] and the Great Basin. In fact, its range in the Great Basin has substantially decreased since 1987 due to a large die-off of singleleaf pinyon in Utah [21]. However, most authors have reported increases in spatial extent and tree dominance and reductions of understory cover and diversity in pinyon-juniper woodlands [15,39,42,60,62,65,67,81,96,167,180,199,204,218,235]. These changes may be attributed to the interactions of many variables such as seed distribution by birds, centuries of domestic livestock grazing, changes in fire frequency, and climate change [5,15,48,58,81,85,90,124,197,204]. Some managers have been concerned about the subsequent loss of forage for livestock and big game and have supported efforts to remove trees and seed non-native grasses to create artificial grasslands [49,57,102,122,134,149,232]. Removal of trees tends to result in increased growth of understory species (e.g., see [65,66,67,216]); however, many "control" operations fail to meet their objectives or fall short of projected increases in forage production [40,122,169,188,244]. Furthermore, tree removal can have serious impacts on hydrology, nutrient cycling, soil fertility [81,204], and wildlife and archaeological resources [57,81,122,124,165]. Often the resulting slash from these operations is piled and burned, resulting in high heat levels that leave some areas sterilized and free of vegetation for over 20 years [165].

While tree encroachment may adversely affect habitat by reducing forage for some wildlife species, the total removal of trees may not be an effective alternative. Periodic removal of some singleleaf pinyon trees using prescribed fire or silvicultural treatments, while leaving areas of trees close by, creates more effective habitat for wildlife [34,182,186,206]. It is important that a variety of age classes be represented on the landscape, since each successional stage supports different species in different amounts. Old growth pinyon-juniper woodlands, for example, are home to many species of reptiles, and any changes in woodland tree density may have an effect on lizard populations [157]. Also, while exotic grasses may be more successful than native species at regeneration after tree removal, seeding exotics may "break the chain" successionally by replacing early successional hosts of mycorrhizae shared by later successional species [206]. Singleleaf pinyon removal and woodland conversion projects have the potential to increase cover of undesirable exotic species such as cheatgrass at the expense of the more desirable native forage species [193].

It remains unclear what type of stand structure provides the most desirable watershed conditions in pinyon-juniper woodlands. Some managers suggest that a high density of trees causes erosion, while others suggest that centuries of grazing and destruction of cryptobiotic crusts have caused erosion in these woodlands. No studies support the claim that deforestation reduces erosion and protects watersheds [48].

Insects and diseases affecting singleleaf pinyon include pinyon needle scale, which weakens trees and subjects them to killing attacks by bark beetles (pinyon ips) [215,240]. Pinyon pine sawfly can also be a serious defoliator [215]. Singleleaf pinyon is parasitized by the pinyon dwarf-mistletoe [91]. Black stain root disease causes extensive mortality in single leaf pinyon in portions of the San Bernardino Mountains in southern California [187]. Cone and seed insects associated with singleleaf pinyon, such as the pinyon cone beetle (Conophthorus monphyllae), coneworms (the larval stage of Dioryctria moths), and the pinyon cone borer may need to be considered if nut production is an objective [38,147,160]. Variability of stand conditions within a forest or region may reduce the risk of widespread mortality due to insect pests and diseases and may be achieved by reintroduction of fire to reduce biomass and fuel loads in some areas [51]. Removal of all pinyon slash larger than 3 inches (8 cm) will usually prevent pinyon ips populations from reaching epidemic proportions [22,143].

Nearly 70 taxa of narrow endemic plants, many of which are listed as threatened, endangered, or sensitive, or have been considered for listing, are found in pinyon-juniper communities in Utah, and may be somehow dependent on the pinyon-juniper association. An understanding of the habitat (geology, soils, hydrology) and biology of these protected species is also an important aspect of management decisions [77]. Cryptobiotic crusts are important features of pinyon-juniper ecosystems, as they are thought to increase infiltration, reduce erosion, contribute to soil organic matter, and fix nitrogen [8,233]. It is important to consider impacts of management activities on these crusts, as they are fragile and recover slowly [82]. Slash management is also an important consideration in the nutrient-poor environment typical of singleleaf pinyon communities [58], and the culling of dead and dying trees through fuel wood and salvage operations removes nutrients as well as habitat for insects and wildlife [42]. However, Thran and Everett [208] found little change in soil nutrients after complete tree removal in Nevada.

Management of singleleaf pinyon involves a complex ecosystem, sometimes requiring landscape-scale objectives [110]. Because stand characteristics of singleleaf pinyon woodland vary with geography, topography, local site conditions, understory community and general climate, effective management must work within the community ecology of the woodland sites of interest, including all the species present and the history of use and change on the site, as well as its current ecological status [53,81,204]. Gottfried and Severson [81] provide a detailed review of past management objectives and procedures and an evaluation of their relative successes. Ellenwood [53] suggests some generalized management objectives commonly applied to pinyon-juniper forests (sustaining grassland, sustaining woodland, and sustaining woodland savannah), and silvicultural systems that may be used to achieve these objectives. Other silvicultural recommendations for singleleaf pinyon woodlands are available [80,82,178]. Miller [148] presents examples of holistic woodland management which take into account the human element and cultural and spiritual requirements of the Native peoples who live in pinyon-juniper ecosystems. He also suggests "community forestry" practices as good templates for woodland planning [149].

Related categories for SPECIES: Pinus monophylla | Singleleaf Pinyon