Physiognomy and Structure: Tall and stunted conifer trees with at least 10% canopy cover. These are upland forests and woodlands Dominant taxa include Hesperocyparis macrocarpa, Hesperocyparis goveniana, Hesperocyparis abramsiana, Pinus sabiniana, Pinus coulteri, Pinus attenuata, Pinus quadrifolia, or Juniperus californica.

Floristics: Dominant conifers include cypresses Hesperocyparis abramsiana (= Callitropsis abramsiana), Hesperocyparis bakeri (= Callitropsis bakeri), Hesperocyparis forbesii (= Callitropsis forbesii), Hesperocyparis goveniana (= Callitropsis goveniana), Hesperocyparis macnabiana (= Callitropsis macnabiana), Hesperocyparis macrocarpa (= Callitropsis macrocarpa), Hesperocyparis nevadensis (= Callitropsis nevadensis), Hesperocyparis pigmaea (= Callitropsis pigmaea), Hesperocyparis sargentii (= Callitropsis sargentii), and Hesperocyparis stephensonii (= Callitropsis stephensonii); pines Pinus sabiniana, Pinus quadrifolia, Pinus coulteri, Pinus attenuata, Pinus muricata, Pinus torreyana, and Pinus radiata (native, non-plantation stands). Pinus sabiniana, Pinus coulteri, and Pinus attenuata are widespread conifers of this group. Stands have varied species composition and structure, depending on their juxtaposition to other stands of chaparral, coastal scrub, desert scrub, or woodland vegetation. In some stands, the conifers are open-grown trees over grassy understories. In others, they form a mixed canopy with other trees or shrubs. Companion canopy species vary depending upon geographic location and include Arbutus menziesii, Notholithocarpus densiflorus (= Lithocarpus densiflorus), Calocedrus decurrens, Pinus jeffreyi, Pinus monophylla, Pinus ponderosa, Pseudotsuga menziesii, Pseudotsuga macrocarpa, Quercus agrifolia, Quercus chrysolepis, Quercus kelloggii, Quercus wislizeni, or Quercus douglasii. Shrub layers are sparse to continuous, and often variable. The herbaceous layer is usually sparse. Understory shrubs may include Adenostoma fasciculatum, Adenostoma sparsifolium, Arctostaphylos glauca, Arctostaphylos glandulosa, Arctostaphylos viscida, Ceanothus cuneatus, Ceanothus greggii, Cercocarpus montanus, Eriogonum fasciculatum, Agave deserti, Artemisia tridentata, Coleogyne ramosissima, Ephedra spp., Hesperoyucca whipplei, Lepidospartum squamatum, Nolina parryi, Purshia mexicana, Quercus cornelius-mulleri, Quercus durata, Rhododendron macrophyllum, Rhus ovata, Vaccinium ovatum, and Yucca schidigera.

Highly localized endemic tree taxa include Hesperocyparis macrocarpa, Hesperocyparis goveniana, Hesperocyparis abramsiana, Pinus contorta var. bolanderi, Pinus radiata, and Pinus torreyana that occur in scattered groves along the coast. Pinus attenuata, Pinus contorta var. contorta, and Pinus muricata are dominant or codominant in these and other occurrences. These occurrences can also include pygmy woodland expressions where indurated subsoil underlies acidic sands (ancient marine terraces). Other associated plant species include Arctostaphylos hookeri ssp. montana (= Arctostaphylos montana), Arctostaphylos nummularia, Arctostaphylos tomentosa, Ledum groenlandicum, Vaccinium ovatum, Gaultheria shallon, Rhododendron macrophyllum, and Morella californica (= Myrica californica). The lichen and moss component of this group is very diverse, includes Cladonia spp., and can be abundant in these communities. Other highly localized endemic taxa include Hesperocyparis nevadensis and Hesperocyparis stephensonii that occur inland in scattered groves.

Dynamics:  Stands of many of these warm-temperate conifer alliances are largely perpetuated through periodic fire. Pinus attenuata, Pinus contorta var. bolanderi, Pinus radiata, Pinus muricata, and all the Hesperocyparis species are considered serotinous species (Barbour et al. 2007). Fire heats the resin-sealed cones and initiates seed dispersal. Only limited seed is released during periods of prolonged hot dry weather. Pinus coulteri, and to a lesser degree Pinus torreyana, are somewhat serotinous and, depending upon populations, may retain seeds in cones on the trees for several years until released by fire. All of these serotinous or semi-serotinous species are relatively short-lived. Stand-replacing fire events optimally occur between 50- and 125-year intervals. Fires spaced more closely tend to reduce stands because trees cannot develop large seedbanks stored in the cones, while fires at very long intervals tend to cause senescence in the conifers and many trees die without releasing seed.

Another suite of species diagnostic of this group, including Pinus sabiniana, Juniperus californica, and Pinus quadrifolia, are not serotinous, but their stand dynamics are also affected by fire. These species are fire-sensitive with relatively thin bark and typically do not release seed stored in cones following fire scorching. Instead these species tend to form stands only under conditions of low fire intensity or in local fire-protected areas. Pinus sabiniana and Pinus coulteri tend to form stands in chaparral where fire has been absent for many decades or may also form stands in drier portions of the state where shrub and herbaceous understories are relatively sparse and do not carry fire regularly. Pinus quadrifolia is the most restricted of these fire-sensitive species and only forms stands in older stands of chaparral or in steep rocky terrain in semi-desert conditions in the Peninsular Ranges of southern California. Pinus sabiniana is largely restricted to the foothills surrounding the Great Valley and is also found throughout the California Coast Ranges inland from the immediate maritime zone.