This important habitat contains two distinct sub-groups: Juniper Savanna and Pinyon-Juniper (P-J) forest. These areas are widely scattered throughout the state. They occur to a lesser extent in the eastern plains and the Mexican highlands. In the Mogollon Rim and the Mexican Highlands, this forest has a larger oak component. In the very southern mountains, savanna may actually be composed of oak rather than juniper (Dick-Peddie 1993).

Juniper Savanna and Pinyon-Juniper occur above desert or grassland vegetation and below pine forest (Peiper 1977). The elevation of this habitat type ranges from 4650-7130 feet, with extremes between 3255 and 7700 feet (Brown 1994). As elevation increases, pinyon dominance often increases, juniper density decreases, total tree density increases, and trees become larger in stature (Peiper 1977, LaRue 1994). Although soils underlying P-J vary, they are often shallow, rocky, low in fertility, and are derived from a wide range of parent material including granite, basalt, limestone, sandstone, and shale (Pieper 1977).

Pinyon-Juniper habitat is a cold-adapted, evergreen woodland that is characterized by varying codominance of juniper (Juniperus spp.) and pinyon (Pinus spp.). Junipers are often the most abundant of the two dominant species, but pure stands of either species may occur. The most common juniper in New Mexico is one-seed juniper (Juniperus monosperma) . It may share dominance with Rocky Mountain juniper (J. scopulorum) and/or Utah juniper (J. osteosperma) in the north, and alligator juniper (J. deppeana) and/or redberry juniper (J. erythrocarpa) in the south. The most common pinyon is Colorado pinyon (Pinus edulis), while border pinyon (P. discolor) also occurs. Oaks may form a larger component of P-J woodland in southern mountain areas. These can include Gambel (Quercus gambelii), gray (Q. grisea), and Arizona white (Q. arizonica) oak. The understory varies from completely open to very dense, especially where sagebrush (Artemisia spp.) is present. Understory species include those of Montane or Great Basin Shrubland and of Chihuahuan and Plains and Mesa Grasslands.

The stature of Pinyon-Juniper rarely exceeds 39ft (12m) in height. Typical P-J habitat exhibits an open woodland arrangement with well-spaced trees. In lower elevation P-J woodland, trees are widely spaced with a grass understory. In general, these trees are all one species of juniper. If fewer than 130 trees per ac (320/ha) are present, this is referred to as Juniper Savanna (Dick-Peddie 1993). The Savanna is an ecotone between woodland and grassland. As the elevation rises within this habitat, trees become more dense and moisture more abundant, resulting in Pinyon-Juniper woodland, which may form a closed canopy forest at its upper boundary. In northern portions of the state, densities can reach 280" 48 trees per acre ( 690 " 120 per hectare) (Moir and Carleton 1987).

Junipers have encroached upon large areas that were once grassland. Encroaching junipers are usually found at a lower elevation than pinyons. There is no evidence that P-J woodlands, with mature pinyon trees 100-200 years old, were formerly grasslands that have been invaded by trees (Little 1977).

Wide-scale conversion of P-J woodland to grassland for cattle forage began after World War II. Conversion was accomplished by various methods including cabling, bulldozing, hand chopping, grubbing and burning. An anchor chain dragged between two tractors was frequently used to remove trees. Seeding with grass, especially crested wheatgrass, followed. This conversion occurred in two types of habitat: areas of grasslands, mostly at low elevations where juniper, but not pinyon, had invaded due to overgrazing and lack of fire, and in areas of natural pinyon-juniper woodlands. In the southwest, conversion of P-J to grassland has included destruction of mature pinyon trees on greater than a few hundred thousand acres (Little 1977). Widespread conversion has decreased primarily due to the low cost-benefit ratio and also because of destruction to archaeological sites (Lanner 1981, H. Schwartz pers.comm.).

Conversion of natural P-J woodlands to grassland for forage production and big-game values has resulted in ambiguous results. Seeding to improve forage has generally proved unsuccessful over large areas (Gottfried et al. 1994). In one study, an undisturbed Pinyon-Juniper stand had greater cover of grasses and forbs than a cabled area after 20 years (Gottfried et al. 1994). The impact of P-J conversion on native wildlife has been documented (Swenson 1977 and others). Mule deer and elk use was highest on undisturbed Pinyon-Juniper. Natural P-J has greater bird species diversity and higher numbers of individuals (with the exceptions of wintering flocking species) than converted areas (Swenson 1977).

Historic grazing practices have also had an effect both adjacent to, and within, the P-J woodland matrix. These practices have resulted in soil and vegetation degradation. Soil compaction contributes to or causes increased soil erosion, decreased water infiltration, and reduced soil fertility. In one study, bare ground increased from 8% on a relict, undisturbed site to 65% on a continuously grazed site (Swenson 1977). Browse species became heavily used, contributing to hedging and an increase in less desirable species. While cool season grasses covered 65% of the ground on an undisturbed site, they were completely eliminated on a continuously grazed site (Swenson 1977). A rest-rotation grazing system in place for 15 years appeared to produce a situation intermediate to the undisturbed and grazed sites: 35% cool season grasses and 35% bare ground (Swenson 1977).

The loss of a continuous herbaceous cover, especially in adjacent grasslands, due to overgrazing, has produced a situation where P-J stands do not have enough fuel to carry fire and eliminate young trees. Fire suppression has also contributed by allowing small trees to successfully outcompete grasses for water, nutrients and light. Grazing and erosion cause drier surface soils, which favor deep-rooted species rather than grasses (Gottfried et al. 1994).

Brown-headed Cowbird parasitism rates on Pinyon-Juniper sites may play a significant role in songbird breeding success. Goguen and Mathews (1996) found that three species (Plumbeous Vireo, Blue-gray Gnatcatcher and Western Tanager) in northeastern New Mexico were parasitized in excess of 75% on both grazed and ungrazed plots. Other species also suffered from parasitism, including Virginia's and Black-throated Gray Warbler.

Pinyon-Juniper is important as a seasonal habitat for elk and mule deer. P-J is also used for firewood, pinyon nuts, fence posts, charcoal, railroad ties, mining timbers, and livestock forage (Tueller 1979). Increasingly, Pinyon-Juniper is valued for its aesthetic and cultural values, as well as for providing habitat for threatened and endangered species and management species of concern. It should be noted that the western United States has a global responsibility for this unique habitat.

Several rural and indigenous populations including the Navajo, Zuni and Ute have spiritual connections with Pinyon-Juniper woodlands. They derive food, plant and animal products for ceremonies, etc. from Pinyon-Juniper. In addition, Pinyon-Juniper contains many prehistoric and historic archaeological sites.

Although bird assemblages in Pinyon-Juniper vary with stand characteristics, 73 bird species are reported to breed in P-J (Balda and Masters 1980). However, not all of these species will occur at any one site. Only a few bird species are considered obligates or semi-obligates of this habitat. These include: Gray Flycatcher, Ash-throated Flycatcher, Western Scrub-Jay, Pinyon Jay, Juniper Titmouse, Bushtit, Bewick's Wren, Gray Vireo, Black-throated Gray Warbler and Lark Sparrow. In one study of Pinyon-Juniper birds, 87% of the foliage nests and 87% of the cavity nests were located in juniper (LaRue 1994). Total breeding density increases as total tree density increases (Balda and Masters 1980, La Rue 1994). As pinyon density increases, densities of Gray Flycatcher, Mountain Chickadee and Black-throated Gray Warbler increase (La Rue 1994). Large annual fluctuations in breeding densities may occur (LaRue 1994). Juniper seeds, when present in winter, are an important food source for a variety of thrushes.

Impacts to this habitat include: 1) fuelwood cutting, especially older, mature trees 2) development, which contributes to habitat fragmentation, 3) mistletoe, 4) high intensity grazing, 5) fire suppression, 6) catastrophic fire, and 7) P-J conversion to grassland.

Physiographic Areas covered: Mexican Highlands, Chihuahuan Desert, Mogollon Rim, Colorado Plateau, Pecos and Staked Plains.

Bird Habitat Requirements, Population and/or Habitat Objectives:
(in taxonomic order)

Retain mature, relatively undisturbed or recovering Pinyon-Juniper. Avoid seeding of exotic grasses and cultivation of habitat where possible (Janes 1985).

Over time and a large landscape an optimal goal is:

15 - 35% mature Pinyon-Juniper types with natural openings

20 - 30% regenerating and/or isolated juniper

45 - 55% middle age Pinyon-Juniper and spaced Juniper Woodlands/Savanna

Soil conditions and elevation will determine the mix at any particular site. In general, a higher percentage of old-growth pinyon should be managed for at higher elevations. At lower elevations, a higher percentage of mid-age trees and savanna is more appropriate.

Firewood-cutting/timber cutting - cutting can be helpful to thin areas that are in need of opening. However, as old-growth pinyon-juniper takes many years to develop, it is recommended that firewood cutting be restricted to mid-age or younger trees.

Grazing - Short-term/rest-rotation grazing reinvigorates grasses, while limiting soil compaction, erosion, and soil dehydration. If fire is also allowed or reintroduced into the managment scheme, it will limit sprouting of unpalatable and invasive shrubs and trees, especially in mid-age to younger stands. Long-term grazing or year-round grazing is especially harmful to grasslands on the edge of juniper savanna. It promotes bare ground as well as the growth of deep-rooted shrubs and juniper over grasses.

Cool fire is characterized by low flames of 2-3 feet, burning grass and young shrubs and only occasionally, burning larger, older trees. It does not create conditions that sterilize the soil: killing micro-organisms that assist the water intake process for plants and the decomposition of organic material into soil. Allowing or reintroducing this type of fire is desirable, especially in juniper savanna or mid-age Pinyon-Juniper stands.

Hot fire - These stand replacing fires are considered "catastrophic". They are also part of the natural condition in these forests. Historically, they occurred in old-growth Pinyon-Juniper every 50 -300 years (Scurlock 1998). Today, these fires occur where fuel build-up allows fire to burn through an area killing all or most the trees. These fires tend to sterilize the soil, thus creating conditions that do not allow a quick vegetative recovery.

Mistletoe - dwarf mistletoe is a parasite that indicates an unhealthy tree. Dwarf mistletoe is most often found in pinyon (R. Cassidy). In areas where mistletoe is extremely abundant, a reduction in trees through burning or mechanical means may be desirable. Since dwarf mistletoe can eject seeds as far as 60ft., a containment zone of no more than 65ft. should be established. True mistletoe is more often found in junipers. It can be an important food source, especially in southern woodlands and does not need control.

Chaining - Because of the high cost of mechanically converting Pinyon-Juniper to grassland and the low benefit obtained from such methods, maintaining grasslands through short-term grazing and fire regimes is recommended.

Development - Development may occur in this habitat, especially in areas near existing urban areas. Developers should consider instituting high-density building in smaller areas of Pinyon-Juniper rather than fragmenting large areas with low density buildings. Some Pinyon-Juniper bird species can maintain populations in areas which have been developed if most of the larger trees are left standing.

Additional species for which monitoring is recommended:

• Cassin’s Kingbird
• Loggerhead Shrike
• Juniper Titmouse
• Common Bushtit
• Western Bluebird

Education: Call attention to the importance of this habitat, the cultural and aesthetic values, and our global responsibility for this habitat.

Table 2. Pinyon-Juniper Woodland: Priority Species Habitat Factors