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U.S. Forest Service

Montane Mixed Conifer Forest

Montane mixed conifer forests are the glue that binds together the many different serpentine plant communities within the Klamath-Siskiyou Mountains. The serpentine barrens, meadows, Jeffrey pine savanna, rock outcrops, and all the other distinct communities found on the serpentines of this bioregion are within or at the margins of the montane mixed conifer forest matrix. The mixed conifer forest forms the most continuous cloth over the landscape here. Under the trees, the understory may be dense or lacking; the shrub layer may give way to grass or rocky openings.

These forests are found over a wide range of elevations and topographic positions. The most important influences on localized plant community composition are elevation, precipitation, soil depth, and the degree of the soil serpentine syndrome: soil toxicity and available calcium.

The driest sites, whether from shallow rocky soil, southern exposure, or less precipitation, are dominated by Jeffrey pine and incense-cedar, with lesser numbers of Douglas-fir, sugar pine, white fir, and western white pine. The understory is scant.

Upper montane mixed conifer forest  meets a wildflower-covered hillside on the slope of Mt. Eddy. Upper montane mixed conifer forest, dominated by red fir (Abies magnifica) meets a wildflower-covered hillside on the slope of Mt. Eddy. Photo by Julie Kierstead Nelson.

Upper Trinity River. Snow lingers in this April scene on the upper Trinity River, with incense-cedar (Calocedrus decurrens) in the foreground. Photo by Julie Kierstead Nelson.

Mixed conifer forest. White fir (Abies concolor) dominates this variation of mixed conifer forest, with bitter cherry (Prunus emarginata) in sunny openings. Photo by Julie Kierstead Nelson.

Old red fir forest. This old red fir forest has a fairy-tale atmosphere, with shaggy chartreuse wolf lichen clothing the tree trunks and marking the depth of the winter snow pack. Photo by Julie Kierstead Nelson.

More mesic sites, near the coast or higher in elevation, have a stronger component of white fir, along with a more even mix of Jeffrey, sugar, western white and lodgepole pines, Douglas-fir, and incense-cedar, with an understory of dwarf tanbark-oak (Lithocarpus densiflorus var. echinoides), huckleberry-oak (Quercus vaccinifolia), and pinemat Manzanita (Arctostaphylos nevadensis). The Klamath-Siskiyou endemic Brewer spruce (Picea breweriana) is occasionally found in this community.

Jeffrey pine on a rocky ridge. Jeffrey pine develops great character on rocky ridges, while mixed conifer forests clothe the nearby slopes. Photo by James R. Nelson.

The Pacific Crest Trail winding its way through montane mixed conifer forest dominated by western white pine and white fir. The Pacific Crest Trail winds its way through montane mixed conifer forest dominated by western white pine (Pinus monticola) and white fir (Abies concolor), on the Sacramento/Trinity River divide. Photo by Julie Kierstead Nelson.

At the upper end of the mixed conifer zone, just below subalpine woodland, white fir is replaced by Shasta red fir (Abies magnifica) and mountain hemlock (Tsuga mertensiana), and the understory in this cold, snowy zone may include common juniper (Juniperus communis) and the rare Klamath manzanita (Arctostaphylos klamathensis).

Rare plants in montane mixed conifer forests on serpentine are most often found in shrubby, grassy, or rocky openings, rather than under a dense canopy of trees. Rare plants associated with serpentine mixed conifer forests of the Klamath-Siskiyou bioregion include:

  • Horkelia sericata
  • Iris innominata
  • Lilium bolanderi
  • Lilium rubescens
  • Lomatium howellii
  • Poa piperi
  • Vancouveria chrysantha
  • Senecio macounii
  • Sanicula peckiana
  • Dicentra formosa ssp. oregana
  • Eriogonum pendulum
  • Streptanthus howellii
  • Arctostaphylos hispidula
  • Arnica cernua
  • Phacelia dalesiana
  • Arctostaphylos klamathensis
  • Minuartia stolonifera

Montane mixed conifer forest with Klamath manzanita in the understory. Cooler temperatures enable Klamath manzanita (Arctostaphylos klamathensis) to grow at high elevations in the Scott Mountains. This low-growing rare shrub is similar to pinemat manzanita, but is not as drought tolerant. The darker and denser-leaved white fir (Abies concolor) trees shown in the canopy are an additional indicator of cooler temperatures and higher soil moisture content. Photo by Julie Kierstead Nelson.

Photo Gallery

Our thanks to CalPhotos and its many contributors for many of the pictures in this photo gallery.

  • Angelica tomentosa

    Angelica tomentosa on Mt. Eddy. Photo by Julie Kierstead Nelson.

  • Arctostaphylos klamathensis

    Arctostaphylos klamathensis. Photo by Julie Kierstead Nelson.

  • Epilobium siskiyouense

    Epilobium siskiyouense. Photo by Norman Jensen, Photo·grafica botanii.

  • Penstemon parvulus

    Penstemon parvulus. Photo by Julie Kierstead Nelson.

  • Phacelia dalesiana

    Phacelia dalesiana. Photo by Ken DeCamp.