II. Calocedro decurrentis-Pinetea jeffreyi Rivas-Martínez & Sánchez-Mata 1997

IIb. Abietetalia magnifico-lowianae ordo novus hoc loco

Close conifer or mixed conifer and broad leaved meso, macro and megaforests which produce mull humus. They grow on all types of substratums, on mediterranean pluviseasonal oceanic, hyperoceanic to semicontinetal bioclimates in subhumid to hyperhumid supra and oromediterranean belts. In hyperoceanic areas these forests can be found in upper mesomediterranean level (Lithocarpo-Sequoietum sempervirentis); in the mountains semicontinental highlands, as timberline shrubby vegetation can be found in the cryoromediterranean belt.

This second new order includes three alliances. 1. Abietion magnificae: climatophilous euoceanic or semicontinental oromediterranean, upper subhumid to humid and hyperhumid; this alliance is widely distributed along the Sierra Nevada-Transcascadian and Klamath-Ciscascadian sector"s summit territories. 2. Querco kelloggii-Abietion lowianae: climatophilous semicontinental supra and oromediterranean subhumid-humid, with the same chorological distribution as the precedent. 3. Arbuto menziesii-Lithocarpion densiflori: climatophilous hyperoceanic or euoceanic supramediterranean and upper mesomediterranean humid to hyperhumid, widely distributed along the North Coastal and Klamath-Ciscascadian sector territories, and very local in hyperhumid western valleys of Sierra Nevada. Bioclimatical diagnosis: Ic 5-21, Itc < 250, Tp 400-1700, Io > 3.0.

Typus nominis: Abietion magnificae alliancia nova hoc loco.

Characteristic species: Abies concolor (t), Allophyllum integrifolium, Chimaphila menziesii (t), Collinsia torreyi, Kelloggia galioides, Lonicera conjugialis, Luzula parviflora (t), Monardella odoratissima subsp. pallida, Pedicularis semibarbata, Pinus contorta var. murrayana, Pinus ponderosa var. ponderosa, Quercus garryana var. garryana, Quercus kelloggii, Ribes roezlii, Spiraea douglasii, Triteleia ixioides subsp. analina, Valeriana californica, Viola purpurea, Wyethia mollis.

Meso, macro y megabosques cerrados de coníferas o mixtos de coníferas y latifolios, formadores de humus mull, que prosperan sobre todo tipo de sustratos, en bioclima mediterráneo pluviestacional oceánico, de hiperoceánico a semicontinental, en los pisos bioclimaticos supra y oromediterráneo subhúmedo a hiperhúmedo. En ambientes hiperoceánicos pueden descender al horizonte superior mesomediterráneo (Lithocarpo-Sequoietum), así como en los semicontinentales de alta montaña, a modo de formaciones de chaparros supraforestales, alcanzar el piso crioromediterráneo.

El orden Abietetalia magnifico-lowianae reune en su seno tres alianzas. 1. Abietion magnificae: climatófila, desarrollada en bioclima euoceánico o semicontinental, oromediterráneo húmedo-hiperhúmedo, se encuentra ampliamente representada en las áreas cumbreñas de las montañas pertenecientes a los sectores Sierra Nevada-Transcascadas y Klamath-Ciscascadas. 2. Querco kelloggii-Abietion lowianae: climatófila, que prospera en bioclima semicontinental, supramediterráneo y oromediterráneo subhúmedo-húmedo, con similar distribución biogeográfica que la anterior. 3. Arbuto menziesii-Lithocarpion densiflori: climatófila, desarrollada en bioclima hiperoceánico o euoceánico, supramediterráneo y mesomediterráneo superior húmedo-hiperhúmedo, con amplia distribución en los sectores biogeográficos Costero Septentrional y Klamath-Ciscascadas y muy localizado en estaciones hiperhúmedas de Sierra Nevada. Diagnosis bioclimática: Ic 5-21, Itc < 250, Tp 400-1700, Io > 3.0.

3. Abietion magnificae alliancia nova hoc loco

Oromediterranean oceanic, euoceanic or semicontinental, humid and hyperhumid, usually chionophilous, meso and macroforests, that can grow in all kinds of bedrock soils and form humus mull, widely sparced in Sierra Nevada-Transcascadian, and Klamath-Ciscascadian sectors. Three asociations are recognised: 4a. Abietetum magnificae: oromediterranean climatophilous and chionophilous humid-hyperhumid macroforests; 4b. Phyllodoco breweri-Tsugetum mertensianae, upper oromediterranean chionophilous meso-macroforest; 4c. Carici rossii-Pinetum albicaulis, upper oromediterranean humid chionophobous or subhumid climatophilous micro-mesoforest. Bioclimatical diagnosis: Ic 14-21, Itc < 100, Tp 400-900, Io > 5.5.

Typus nominis: Abietum magnificae Oosting & Billings hoc loco.

Characteristic species: Abies magnifica, Abies xshastensis, Aster breweri, Arnica nevadensis, Carex rossii, Erythronium purpurascens, Kalmia microphylla (t), Monardella beneolens, Ligusticum grayi (t), Luzula congesta (t), Luzula divaricata (t), Phyllodoce breweri, Pinus balfouriana, Polemonium californicum (t), Polygonum davisiae, Ribes montigenum (t), Selaginella watsonii (t), Stipa occidentalis.

Meso-macrobosques oromediterráneos, quionófilos o en ciertas situaciones microbosques quionófobos (Carici rossii-Pinetum albicaulis), húmedos e hiperhúmedos, que prosperan en todo tipo de sustratos y generan humus mull. Son propios de Sierra Nevada y de ciertas áreas cumbreñas del sector Klamath-Ciscascadas. Se reconocen tres asociaciones; 4a. Abietetum magnificae, macrobosques oromediterráneos climatófilos o quionófilos, húmedos o hiperhúmedos; 4b. Phyllodoco breweri-Tsugetum mertensianae meso-macrobosques oromediterráneo superior, quionófilos; 4c. Carici rossii-Pinetum albicaulis, micro-mesobosques oromediterráneo superior húmedos y quionófobos o subhúmedos y climatófilos.Diagnosis bioclimática: Ic 14-21, Itc < 100, Tp 400-900, Io > 5.5.

3a. Abietetum magnificae Oosting & Billings associatio nova hoc loco

(Abietetum magnificae Oosting & Billings in Ecol. Monogr. 13(3): 267. 1943 nom. inval., art. 7 CPN)

Oromediterranean chionophilous semicontinental humid and hyperhumid fir forests widely distributed along the Sierra Nevada upper mountain areas; in this territories they have their chorologic optimum but also grow in diverse mountains of the Klamath-Ciscadian sector. This macroforests are generally close and shady and dominated by red fir (Abies magnifica); usually have as accompanying trees white fir (Abies lowiana) and Murray"s lodgepole pine (Pinus contorta var. murrayana) mainly in young stages and lower altitudes. In upper mountain areas is frequent inside the forest Tsuga mertensiana. In winter time the snow pack is extreme (2-3 m) and the snow last until the start of the summer in the shady and highest areas. In this forests is very common the colonization of the trees by the yellow lichens of the genus Letharia. The understory biomass and floristic richness as well as the humicolous sciophytes is variable and conditioned by the madurity and depth of soil which tend to evolve toward andosol mull on the volcanic rocks. The dynamic patterns of the red fir forests show that after the forest clear out (by cut off or out, repeated fires, etc.) grows a community dominated by Pinus contorta var. murrayana or an Arctostaphylos nevadensis facies in the understory. The forest edges open by snow avalanches are colonized by a Populus tremuloides community. Sometimes from Mount Shasta until Sequoia National Forest, in Sierra Nevada, and on similar ecologic environments that Abies magnifica, Abies xshastensis replaces Abies magnifica and tend to develope some hybrids. The red fir forests have been studied by phytosociological methods and published by Oosting & Billings (1943) as Abietetum magnificae; nevertheless these authors have not been published the abundance-dominance indices in his work and the name is invalid in the light of the effective Code of Phytosociological Nomenclature. We try to save this circumstance with the publication of a type relevé in the table 1 which group a selected collection from Lassen Volcanic National Park. Bioclimatical diagnosis: Ic 14-20, Tp 500-850, Io > 6.0.

Relevé typus: Rivas-Martínez reg. num. 1996b: 149; 05.09.1996 achieved with Drs. L. Llorens & D. Sánchez-Mata. Site: Shasta County (California), plain between Hat Lake and Summit Lake, Lassen Volcanic National Park, 40º33'N-121º00'W, surface 200 m2, altitude 1980 m, orientation NE, inclination 10%. Physiognomy and habitat: old and close red fir macroforest (Abies magnifica), 35-40 m high and 120 cm trunk diameter, with some white firs (Abies lowiana) and Murray"s lodgepole pines (Pinus contorta var. murrayana) with a dense herbaceous sciophilous understory, growing on mull deep andosol developed on dacite volcanic rocks. Stimate bioclimatic factors: Mediterranean pluviseasonal oceanic, semicontinental (Ic ~ 18.0), lower oromediterranean (Itc ~ 800), upper humid (Io ~ 8.0). Biogeographical location: Californian Region, North Californian province, Sierra Nevada-Transcascadian sector, Sierra Nevada subsector. Floristic combination: Calocedro decurrentis-Pinetea jeffreyi characteristic species: 5 Abies magnifica, 2 Chimaphila menziesii (t), 2 Hieracium albiflorum, 2 Luzula congesta (t), 2 Pedicularis semibarbata, 2 Pyrola picta, 1 Abies lowiana, 1 Carex rossii, 1 Monardella odoratissima subsp. pallida, 1 Penstemon gracilentus, 1 Pinus contorta var. murrayana, 1 Ribes roezlii; companion species: + Poa bolanderi (table 3, relevé 8).

Asociación que representa a los abetales climatófilos chionófilos oromediterráneos, euoceánicos y semicontinentales húmedos e hiperhúmedos, que se hallan ampliamente distribuidos en los territorios orófilos húmedos del subsector de Sierra Nevada y de algunas montañas elevadas del sector Klamath-Ciscascadas. Se trata de macrobosques densos y sombríos en los que en su madurez domina Abies magnifica al que suelen acompañar en las etapas juveniles y en los niveles inferiores Abies lowiana y Pinus contorta var. murrayana. En las cotas superiores Tsuga mertensiana puede llegar a ser común pero no dominante en el bosque. En la época invernal la nieve alcanza espesores muy considerables (2-3 m) y suele perdurar hasta el comienzo del verano en las zonas más elevadas y sombrías. Es característico de estos bosques la colonización de las cortezas por los líquenes amarillos del género Letharia. La biomasa y la riqueza florística del sotobosque así como los esciófitos humícolas, varian considerablemente en función de la madurez y de la profundidad del suelo, que tiende a evolucionar en los sustratos volcánicos hacia un mull andosol. Los patrones dinámicos que parece seguir muestran que tras la apertura de claros en el bosque (tala selectiva, fuegos, etc.) se instala una comunidad forestal más heliófila, presidida por Pinus contorta var. murrayana, o bien una facies de Arctostaphylos nevadensis en el sotobosque. Los claros abiertos por las avalanchas de nieve son colonizados por Populus tremuloides. Desde Mount Shasta hasta Sequoia National Forest, en Sierra Nevada, en repetidas ocasiones y en ambientes ecológicos semejantes a los del Abietetum magnificae, Abies shastensis reemplaza a Abies magnifica con el que tiende a hibridarse. Los abetales de Abies magnifica fueron estudiados fitosociológicamente y dados a conocer por Oosting & Billings (1943) como Abietetum magnificae; pero al no haber indicado los índices de abundancia-dominancia en su trabajo, el nombre resulta inválido conforme el Código de Nomenclatura Fitosociológica vigente (CPN), circunstancia que tratamos de remediar con la publicación del inventario tipo en la tabla 3 donde se presenta una selección de inventarios procedentes del Parque Nacional Volcánico de Lassen. Diagnosis bioclimática: Ic 14-20, Tp 550-900, Io > 5.0.

3a. Abietetum magnificae (table 3)

Other species: characteristics: Phyllodoce breweri 2 in 1; Polygonum davisiae + in 4; Symphoricarpos rotundifolius 1, Wyethia mollis +, Allium campanulatum + and Dicentra formosa 1 in 5; Osmorhiza chilensis 1 en 9; Ribes nevadense 1, Apocymum androsaemifolium 1, Arabis howellii 1, Ceanothus cordulatus 1 in 10. Companions: Hackelia nervosa +, Brickelia greenei + and Carex brainerdii + in 5; Poa bolanderi + in 6; Sibbaldia procumbens 1 in 7; Lupinus burkei + and Elymus californicus 1 in 9; Pteridium pubescens 1 and Solidago salebrosa + in 10.

Abreviated floristic names: Arabis howellii: Arabis platysperma var. howellii, Monardella pallida: Monardella odoratissima subsp. pallida, Pinus murrayana: Pinus contorta subsp. murrayana, Pteridium pubescens: Pteridium aquilinum var. pubescens, Solidago salebrosa: Solidago canadensis var. salebrosa.

Localities: 1. Shasta County: Lassen Volcanic National Park. Devastated Area-Chaos Crags; 2 and 3. Shasta County: Lassen Volcanic National Park. Manzanita Lake-Devastated Area; 4, 7 and 8. Tehama County: Lassen Volcanic National Park. Brokeoff Mountain. Forest Lake-Summit; 5. Tehama County: Lassen Volcanic National Park. Southwest Entrance-Mill Creek Falls; 6. Shasta County: Lassen Volcanic National Park. Hat Lake-Summit Lake; holotypus; 9. Tehama County: Lassen Volcanic National Park. Brokeoff Mountain. Forest Lake; 10. Tehama County: Lassen National Forest. Lassen Volcanic National Park-Mineral.

3b. Phyllodoco breweri-Tsugetum mertensianae associatio nova hoc loco

Chionophilous meso-macroforests widely distributed along the Sierra Nevada upper oromediterranean hyperhumid territories mainly in shady sides, depressions or near cliffs with a great snow packs (3-5 m). This forests frequently grow at the same high or slightly higher that the Abietetum magnificae forests and with Carici rossii-Pinetum albicaulis forests represent the timberline in this areas. Phyllodoco-Tsugetum mertensianae are a variable dense forests supporting a lot of extreme ecological conditions and frequent snow avalanches which produce some natural edges inside the forest. Whit Tsuga mertensiana as dominant tree, is frequent red fir (Abies magnifica). Moreover, are frequent some chionophilous plants as Sibbaldia procumbens and Juncus balticus; the constant Phyllodoce breweri which grows forming dense populations like a tapestry in the understory. In stations with smaller snow packs Phyllodoco-Tsugetum mertensianae contacts with Abietetum magnificae and in rocky spurs, cliffs and lithosols with Carici-Pinetum albicaulis forests. We present in table 2 some selected relevés from Lassen Volcanic National Park including the type relevé of this association. Bioclimatical diagnosis: Ic 15-19, Tp 400-650, Io > 10.0.

Relevé typus: Rivas-Martínez reg. num. 1996b: 157; 05.09.1996, achieved with Drs. L. Llorens and D. Sánchez-Mata. Site: Shasta County (California), depression close to King Creek, Lassen Volcanic National Park, 40º27'N-121º30'W, surface 100 m2, altitude 2250 m, orientation E, inclination 10%. Physiognomy and habitat: mountain hemlock chionophilous macroforest with Phyllodoce breweri in the understory, 25-30 m high and 150 cm trunk diameter, gley andosol hydromoder on coluvial volcanic dacite sediments; adjacent climatophilous forest vegetation: red fir macroforest (Abietetum magnificae), edafoxerophilous chionophobous microforest vegetation: Carici rossii-Pinetum albicaulis. Stimate bioclimatic factors: Mediterranean pluviseasonal oceanic, semicontinental (Ic ~ 18.0), upper oromediterranean (Tp ~ 600), upper humid (Io ~ 9.0). Biogeographical location: Californian Region, North Californian province, Sierra Nevada Transcascadian sector, Sierra Nevada subsector. Floristic combination: Calocedro-Pinetea jeffreyi characteristic species: 5 Tsuga mertensiana, 4 Phyllodoce breweri, 2 Juncus parryi, 2 Ligusticum grayi, 1 Abies magnifica, 1 Erythronium purpurascens; companion species: 2 Sibbaldia procumbens, 1 Lupinus obtusilobus, + Eriogonum umbellatum var. polyanthum. (table 4, relevé 2).

Meso-macrobosques chionófilos ampliamente distribuidos en el piso oromediterráneo superior húmedo-hiperhúmedo de Sierra Nevada, en particular en umbrías, depresiones o pie de cantiles en los que se acumula gran cantidad de nieve (3-5 m). Catenalmente suelen disponerse en un nivel altitudinal igual o superior al Abietum magnificae y con el Carici-Pinetum albicaulis, representan el límite superior forestal o incluso supraforestal achaparrado en el piso crioromediterráneo inferior (Tp 400-450). Se trata de bosques de densidad variable sometidos a condiciones extremas, donde las avalanchas de nieve resultan frecuentes y producen un aclarado natural del bosque. Además de Tsuga mertensiana, que es dominante, pueden hallarse algunos abetos rojos (Abies magnifica). Además de algunos elementos chionófilos como Sibbaldia procumbens y Juncus balticus, es constante Phyllodoce breweri que forma extensas colonias rastreras en el sotobosque. En estaciones menos innivadas Phyllodoco-Tsugetum mertensianae se pone en contacto con el Abietetum magnificae y en los espolones y litosuelos poco innivados con los bosquecillos de Carici rossii-Pinetum albicaulis. En la tabla 4 presentamos una selección de inventarios procedentes del Parque Nacional Volcánico de Lassen. Diagnosis bioclimática: Ic 15-19, Tp 400-600, Io > 6.0.

3b. Phyllodoco breweri-Tsugetum mertensianae (table 4)

Other species: characteristics: Ligusticum grayi (t) 2 en 2. Companions: Eriogonum polyanthum 1 in 1; Sibbaldia procumbens 2 in 2; Spiraea splendens 3 in 8; Lupinus andersonii 2, Eriogonum nivale 1 and Polygonum shastense 2 in 4; Danthonia californica + in 8; Holodiscus discolor + en 9.

Abreviated floristic names: Arabis howellii: Arabis platysperma var. howellii, Eriogonum nivale: Eriogonum ovalifolium var. nivale, Eriogonum polyanthum: Eriogonum umbellatum var. polyanthum, Monardella pallida: Monardella odoratissima subsp. pallida.

Localities: 1. Shasta County: Lassen Volcanic National Park. Lake Helen; 2. Shasta County: Lassen Volcanic National Park. King Creek; holotypus; 3. Shasta County: Lassen Volcanic National Park. Bumpass Hell-Cold Boiling Lake; 4. Shasta County: Lassen Volcanic National Park; 5 and 10. Shasta County: Lassen Volcanic National Park. Emerald Lake-Lassen Peak; 6 and 8. Shasta County: Lassen Volcanic National Park. Bumpass Hell; 7. Shasta County: Lassen Volcanic National Park. Lassen Peak; 9. Tehama County: Lassen Volcanic National Park. Brokeoff Mountain.

3c. Carici rossii-Pinetum albicaulis D.W. Taylor associatio nova hoc loco

(Pinus albicaulis-Carex rossii association D.W. Taylor, "Ecology of the Timberline Vegetation at Carson Pass, Alpine County, California", University of California, Davis. 1976 PhD diss. inedit.; Junco parryi-Pinetum albicaulis M. T. Burke in Madroño 29(3): 170. 1982 nom. inval., arts. 2b, 5, 7 CPN)

These Chionophilous Pinus albicaulis micro-mesoforests grow in the upper oromediterranean humid-hyperhumid territories and are widely distributed along the Klamath and Sierra Nevada summit areas. They are localized forests with Pinus contorta var. murrayana as frequent tree in the overstory growing in winter non-snowed areas. This forests are developed on rocky cliffs, spurs and rough slopes. In upper oromediterranean subhumd areas, as mostly os Sierra Nevada pass and high eastern valleys (Tioga Pass, Sonora Pass, Ebbetts Pass, Carson Pass, Luther Pass, etc.) could represent the climacic vegetation and then is frequent Juniperus occidentalis var. australis (Carici-Pinetum albicaulis juniperetosum australis). In table 3 we publish some selected relevés of this new association from Lassen Volcanic National Park. The California Pinus albicaulis forests, named Carici rossii-Pinetum albicaulis was described by D.W. Taylor (1976) in his PhD dissertation, unpublished according to effective CPN. We try to remedy this circumstance in our work publishing the obliged type relevé and showing in the table 5 some selected relevés from Lassen National Park. Bioclimatical diagnosis: Ic 16-21, Tp 450-650, Io > 5.5.

Relevé typus: Rivas-Martínez reg. num. 1995c: 43, 27.07.1995, achieved with Drs. F. Alcaraz, J. Delgadillo & M. Peinado. Site: Alpine County (California), south slope of the Ebbetts Peak near Ebbetts Pass, 38º35'N-119º50'W, surface 100 m 2, altitude 2700 m, orientation S, inclination 30%. Physiognomy and habitat: whitebark pine open chionophobous microforest with scrubs and grass in the understory, 8-12 m high and 80 cm trunk diameter, ranker tangel lithosol on granite bedrock; local adjacent chionophilous forest vegetation: Phyllodoco-Tsugetum mertensianae and Abietetum magnificae. Stimate bioclimatic factors: Mediterranean pluvieasonal oceanic, semicontinental (Io ~ 19.0), upper oromediterranean (Tp ~ 500), lower humid (Io ~ 5.0). Biogeographical location: Californian Region, North Californian province, Sierra Nevada-Transcascadian sector, Sierra Nevada subsector. Floristic combination: Calocedro-Pinetea jeffreyi characteristic species: 5 Pinus albicaulis, 3 Carex rossii, 2 Lonicera conjugialis, 2 Pinus contorta var. murrayana, 2 Ribes lasianthum, 1 Monardella odoratissima subsp. pallida, 1 Symphoricarpos rotundifolius, + Prunus emarginata; companion species: 2 Phlox austromontana, 1 Erysimum capitatum var. perenne, + Artemisia tridentata subsp. vaseyana.

Micro-mesobosques quionófobos de Pinus albicaulis, propios del piso oromediterráneo superior oceánico húmedo-hiperhúmedos, pero que como arbusteda achaparrada alcanza el piso crioromediterráneo inferior, ampliamente distribuidos por las áreas cumbreñas de Klamath y Sierra Nevada. Se trata de bosques de Pinus albicaulis, a los que puede acompañar Pinus contorta var. murrayana, que prosperan en estaciones de poca cobertura de nieve invernal persistente, como roquedos escarpados, espolones y laderas más o menos abruptas. En territorios oromediterráneo superiores subhúmedos, como son muchas de las vertientes, collados y altos valles orientales de Sierra Nevada (Tioga Pass, Sonora Pass, Ebbetts Pass, Carson Pass, Luther Pass, etc.), pueden representar la etapa madura, climatófila, y en tales casos suelen llevar Juniperus occidentalis subsp. australis (Carici-Pinetum albicaulis juniperetosum australis). Con la publicación del inventario tipo de la asociación y de una selección de inventarios procedentes del Parque Nacional Volcánico de Lassen (tabla 5). Los bosques californianos de Pinus albicaulis, con el nombre de Carici rossii-Pinetum albicaulis, fueron dados a conocer por D.W. Taylor (1976) en su memoria doctoral, que no llegó a hacerse pública conforme rige el Código de Nomenclatura, circunstancia que ahora se remedia. Diagnosis bioclimática: Ic 16-21, Tp 450-650, Io > 5.5.

3c. Carici rossii-Pinetum albicaulis (table 5)

Abreviated floristic names: Cardamine pachyphylla: Cardamine bellidifolia var. pachyphylla, Phacelia compacta: Phacelia hastata subsp. compacta.

Localities: 1, 2, 3, 5, 6 y 7. Shasta County: Lassen Volcanic National Park. Lassen Peak; 4. Shasta County: Lassen Volcanic National Park. Bumpass Hell-Cold Boiling Lake; 8 and 9. Tehama County: Lassen Volcanic National Park. Summit area of Brokeoff Mountain; 10. Shasta County: Lassen Volcanic National Park. Bumpass Hell Trail.

4. Querco kelloggii-Abietion lowianae alliancia nova hoc loco

Closed climatophilous subhumid and humid supramediterranean and oromediterranean euoceanic and semicontinental megaforests, that can grow in all kinds of bedrock, except on the ultramafic ones, and form humus mull on the soils. They are widespread in the North Californian biogeographical province (Sierra Nevada-Transcascadian and Klamath-Ciscascadian sectors) and in the Transverse Ranges subsector (South Californian Ranges sector) of the South Californian province. It can be recognized three large associations, two in the North Californian province: 4a. Castanopsio sempervirentis-Abietetum lowianae (general in Klamath and Sierra Nevada), 4b. Corno nuttallii-Sequoiadendretum sempervirentis (local in western Sierra Nevada sides), and only one, 4c. Querco kelloggii-Abietetum concoloris, in South Californian province (Transverse Ranges). Bioclimatical diagnosis: Ic: 14-21, Itc: < 230, Tp: 900-1600, Io > 3.0.

Typus nominis: Castanopsio sempervirentis-Abietetum lowianae associatio nova hoc loco.

Characteristic species: Abies bracteata, Abies lowiana, Castanopsis sempervirens (et ord.), Ceanothus integerrimus, Chamaebatia foliolosa, Lilium washingtonianum, Phacelia hydrophylloides, Pinus coulteri, Pseudotsuga macrocarpa, Sequoiadendron giganteum.

Megabosques climatófilos cerrados supra y oromediterráneos subhúmedo-húmedos, euoceánicos y semicontinentales, que viven en todo tipo de sustratos, con excepción de los ultrabásicos serpentínicos o metalicolas pesados y en cuyos suelos se genera humus mull. Se hallan ampliamente representados en de la provincia biogeográfica Californiana Septentrional (sectores Sierra Nevada-Transcascadas y Klamath-Ciscascadas) y en el subsector de las Sierras Transversales (sector Californiano Serrano Meridional) de la provincia Californiana Septentrional. Se reconocen tres ámplias asociaciones; dos en la provincia biogeográfica Californiana Septentrional: 4a. Castanopsio sempervirentis-Abietetum lowianae (general en Klamath y Sierra Nevada), 4b. Corno nuttallii-Sequoiadendretum gigantei (localizada en la vertiente occidental de Sierra Nevada), y solo una en la provincia Californiana Meridional: 4c. Querco kelloggii-Abietetum concoloris (Sierras Transversales). Diagnosis bioclimática: Ic 14-21, Itc < 230, Tp 900-1600, Io > 3.0.

4a. Castanopsio sempervirentis-Abietetum lowianae associatio nova hoc loco

In this large association, which may includes a complex and could be separate in several ones, we join a lot of close climatophilous macroforests with Abies lowiana as dominant tree; nevertheless, Pinus ponderosa var. ponderosa and Pinus lambertiana can be frequent trees inside the forest. These forests are widely distributed along the supramediterranean subhumid and humid semicontinental areas of the North Californian province as many in the Klamath-Ciscascadian sector as Sierra Nevada-Transcascadian sector; the typical forests seem grow in optimum in Sierra Nevada territories but can be found also as climatophilous in the lower oromediterranean subhumid level and then include as frequent trees Pinus contorta var. murrayana and often Abies magnifica, Pinus ponderosa var. ponderosa or even Pinus jeffreyi. These forests are developed forming mull humus on all kinds of substratums, except on ultrabasic or metaliferous rocks, where they are replaced by the ultramafic or serpentinic open pine forests belonging the Querco vaccinifoliae-Pinion jeffreyi alliance; on rich basalts and on young andosols, Pinus jeffreyi are common in the white fir forests. In the shady understory grow a lot of humicolous species widely distributed as Pyrola picta, Chimaphila menziesii, Kelloggia galioides, Chimaphila umbellata, etc. often associated with the californian forest shrub Castanopsis sempervirens; though this plant have a large chorological area -is probably a good characteristic of the order Abietetalia magnificae- we have choosen it to designate this white fir forest association. When the brightness is more intense or the forest has been partially cutted down, Quercus kelloggii can be frequent tree; in the Klamath territories and in the northern areas of the Sierra Nevada subsector, Quercus garryana can be found also a frequen tree. When this more xeric situations are due to the more dry ombroclime influence or to young soils and Pinus ponderosa var. ponderosa is a common tree in the forest, could be to distinguish other more heliophilous association (Querco-Pinetum ponderosae prov.). We show (table 6) a set of selected relevés from Lassen Volcanic National Park and vicinities. Bioclimatical diagnosis: Ic 17-21, Itc < 200, Tp 900-1500, Io 3.0-5.5.

Relevé typus: Rivas-Martínez reg. num. 1996b: 139, 05.09.1996, achieved with Drs. Llorens & Sánchez-Mata. Site: Shasta County (California), hill near Ashpan Snowmobile Park, close to Cost Creek, 40º35'N-121º30'W, surface 600 m 2, altitude 1550 m, orientation N, inclination 15%. Physiognomy and habitat: California white fir forest with small humicolous shaded plants in the understory, 30-35 m high and 100 cm trunk diameter, mull andosol on basalt bedrock; adjacent edaphohygrophilous riparian forest vegetation: Alnus rhombifolia-Populus balsamifera subsp. trichocarpa community. Stimate bioclimatic factors: Mediterranean pluvieasonal oceanic, semicontinental (Ic ~ 19.0), upper supramediterranean (Itc ~ 130, Tp ~ 1100), upper subhumid (Io ~ 4.6). Biogeographical location: Californian region, North Californian province, Sierra Nevada-Transcascadian sector, Sierra Nevada subsector, Lassen district. Floristic combination: Calocedro-Pinetea jeffreyi characteristic species: 5 Abies lowiana, 2 Chimaphila umbellata, 2 Kelloggia galioides, 2 Pyrola picta, 1 Arctostaphylos patula subsp. patula, 1 Carex brainerdii, 1 Castanopsis sempervirens, 1 Monardella odoratissima subsp. pallida, 1 Ribes cereum, + Chimaphila menziesii; companion species: 1 Prunus emarginata, + Hordeum jubatum.

En esta amplia asociación, que en su momento debería desmembrarse en varias, se reunen un buen número de macrobosques climatófilos cerrados, presididos por Abies lowiana pero en los que pueden ser elementos importantes Pinus ponderosa var. ponderosa y Pinus lambertiana, que tienen una gran representación en el piso supramediterráneo subhúmedo y húmedo semicontinental de la provincia Californiana septentrional tanto en el sector Klamath-Ciscascadas como Sierra Nevada-Transcascadas, donde en Sierra Nevada parecen tener su óptimo los más típicos. Estos abetales también pueden prosperar como climatófilos en el piso oromediterráneo inferior subhúmedo, en cuyo caso suelen incorporar Pinus contorta var. murrayana y en ocasiones Abies magnífica, Pinus ponderosa var. ponderosa o incluso Pinus jeffreyi. Se desarrollan formando humus mull, sobre todo tipo de sustratos, excepto sobre roquedos ultrabásicos o muy metalíferos, donde son sustituidos por los pinares abiertos silicibasícolas o serpentinícolas de la alianza Querco vaccinifoliae-Pinion jeffreyi. Sobre basaltos algo ricos y sobre andosoles poco maduros Pinus jeffreyi participa algo en el bosque de abetos. En el sotobosque sombrío hay un buen número de especies humícolas ámplias como Pyrola picta, Chimaphila menziesii, Kelloggia galioides, Chimaphila umbellata, etc., a las que acompaña con frecuencia el arbusto forestal californiano Castanopsis sempervirens, que aunque de más amplia área -probablemente es una característica del orden Abietetalia magnificae- se ha elegido para designar la asociación. En el sotobosque, sobre todo cuando hay más luminosidad o ha habido talas, puede ser común en ocasiones Quercus kelloggii, así como en Klamath y las áreas septentrionales del subsector de Sierra Nevada Quercus garryana. Cuando estas situaciones más xéricas se deben también a la influencia de un ombroclima más seco o a suelos poco desarrollados, y van acompañadas de una gran abundancia o dominio en el bosque de Pinus ponderosa var. ponderosa, tal vez debería aceptarse la existencia de otra asociación más heliofila (Querco-Pinetum ponderosae prov.). En la tabla 6 se da a conocer una selección de inventarios todos ellos procedentes del Parque Nacional Volcánico de Lassen o de sus áreas vecinas. Diagnosis bioclimática: Ic 17-21, Itc < 200, Tp 900-1500, Io 3.0-5.5.

4a. Castanopsio sempervirentis-Abietetum lowianae (table 6)

Other species: characteristics: Ceanothus prostratus + in 1; Asarum hartwegii +, Apocynum androsaemifolium 1 in 7; Pinus jeffreyi x Pinus ponderosa 1, Amelanchier utahensis 1 in 9; Arabis rectissima 1 in 8. Companions: Erysimum capitatum 1 in 8; Elymus californicus +, Viola lobata 1 in 9.

Abreviated floristic names: Cercocarpus intermontanus: Cercocarpus ledifolius var. intermontanus, Monardella pallida: Monardella odoratissima subsp. pallida, Symphoricarpos laevigatus: Symphoricarpos albus var. laevigatus.

Localities: 1 and 3. Shasta County: Lassen Volcanic National Park. Manzanita Lake Entrance; 2. Tehama County: Lassen National Forest. Mineral-Lassen Volcanic National Park; 5 and 4. Tehama County: Lassen Volcanic National Park. Brokeoff Mountain-Mineral; 6. Shasta County: Lassen National Forest. Ashpan Snowmobile Park; 7. Shasta County: Lassen National Forest. Table Mountain; 8. Shasta County: Lassen Volcanic National Park. Sunflower Flat; holotypus; 9. Tehama County: Lassen Volcanic National Park-Mineral. Southwest Boundary.

4b. Corno nuttallii-Sequoiadendretum gigantei Delgadillo associatio nova hoc loco

Megaforests with Sequoiadendron giganteum as dominant tree that can grow up 80 m high and 4 m trunk diameter; as associated trees are frequent Abies lowiana, Calocedrus decurrens and Pinus lambertiana that can surpass 40 m high; in the understory some shrubs as Cornus nuttallii are common as well Pteridium aquilinum var. pubescens and Phacelia hydrophylloides in the grassy level. The actual area of this climatophilous mesophytic association is restricted due to the fires and to wood exploitation; the association characteristic Sequoiadendron giganteum exists as climatophilous tree between the parallels 36º and 39º in the Sierra Nevada eastern side mainly in te upper supramediterranean and lower oromediterranean humid belts, as well in mesophytic compensed stations. The actual optimum of this megaforests are restricted to the Kings Canyon and Sequoia National Park forming a more or less continued belt between 1700 and 2100 m -this area is slightly expanded toward the north and the south as disjunctions- growing mainly in upper supramediterranean humid bioclimate and expanding slightly toward the lower oromediterranean humid bioclimate. The soils are mull cambisols and luvisols, tangel-mull under sequoia, and all are developed generally on granite siliceous rocks.

We agree with the association name and partially with the association concept given by J. Delgadillo in his PhD dissertation (Alcalá de Henares, May 1995). For this reason we validate here his proposal. Bioclimatical diagnosis: Ic 17-20, Itc 70-140, Tp 700-1100, Io 6.0-11.0.

Relevé typus: Rivas-Martínez reg. num. 1995c: 64, 29.07.1997, achieved with Drs. Alcaraz, Delgadillo & Peinado. Site: Tulare County (California), Sequoia National Forest, Mountain Home, Balch Park, valley slopes, 36º15'N-118º40'W, surface 2000 m2, altitude 1850 m, orientation NO, inclination 20%. Physiognomy and habitat: giant sequoia megaforest with California white fir and sugar pine, with Pacific dogwood, ferns and grass in the understory, 50-80 m high and 400 cm trunk diameter, mull and tangel deep cambisol on granitic bedrock; adjacent edaphohygrophilous riparian forest vegetation: Alnus rhombifolia community, edaphohygrophilous vegetation: Chamaebatia foliolosa-Quercus kelloggii-Abies lowiana community. Stimate bioclimatic factors: Mediterranean pluvieasonal oceanic, semicontinental (Ic ~ 19.0), upper supramediterranean (Itc ~ 130), lower subhumid (Io ~ 8.0). Biogeographical location: Californian region, North Californian province, Sierra Nevada-Transcascadian sector, Sierra Nevada subsector, Kings Canyon and Sequoia district. Floristic combination: Calocedro-Pinetea jeffreyi characteristic species: 4 Abies lowiana, 3 Sequoiadendron giganteum, 3 Bromus suksdorfii, 3 Cornus nuttallii, 3 Phacellia hydrophylloides, 2 Apocynum androsaemifolium subsp. pumilum, 2 Calocedrus decurrens, 2 Castanopsis sempervirens, 2 Ceanothus integerrimus, 2 Pinus lambertiana, 2 Ribes roezlii, 1 Galium trifidum, 1 Pseudostellaria jamesiana, + Ceanothus cordulatus, + Pinus ponderosa var. ponderosa, + Pyrola picta, + Silene lemmonii; companion species: 3 Pteridium aquilinum var. pubescens, 2 Lupinus sp., 1 Osmorhiza berteroi, + Clarckia concinna, + Claytonia parviflora, + Corylus cornuta var. californica, + Fragaria vesca subsp. californica, + Pectocarya sp., + Rubus parviflorus, + Smilacina racemosa.

Megabosques en losl que prepondera Sequoiadendron giganteum, que llega a sobrepasar los 80 m de altura y los 4 m de diámetro, en los que como árboles subordinados lleva Abies lowiana, Calocedrus decurrens y Pinus lambertiana, que superan los 40 m; en el estrato de arbustos Cornus nutallii es el más abundante y llamativo, así como lo son en el estrato herbáceo Pteridium aquilinum var. pubescen y Phacellia hydrophylloides. El área de esta asociación climatófila mesofítica algo compensada, cuya característica principal es Sequoiadendron giganteum -que existe como climatófilo entre los paralelos 36º y 39º en la vertiente oriental de Sierra Nevada sobre todo en los pisos supramediterráneo superior y oromediterráneo inferior húmedo, así como en estaciones mesofíticas compensadas- está hoy bastante mermada por las talas y fuegos. Su óptimo se concreta en Kings Canyon y Sequoia National Park a una banda más o menos continua entre los 1700 y 2100 m -que se prolonga de modo disyunto algo hacia el norte y hacia el sur- en bioclima supramediterráneo superior húmedo para entrar ligeramente en el oromediterráneo inferior húmedo. Los suelos son cambisoles y luvisoles de mull, tangel-mull bajo sequoia, en general desarrollados sobre sustratos silíceos graníticos.

Al estar de acuerdo con el nombre, y en gran medida con el concepto, dado a esta asociación por J. Delgadillo en su tesis doctoral (Alcalá de Henares, mayo 1995) damos aquí validez a su propuesta. Diagnosis bioclimática: Ic 17-20, Itc 70-140, Tp 700-1100, Io 6.0-11.0.

4c. Querco kelloggii-Abietetum concoloris associatio nova hoc loco

Close climatophilous macroforests developed in supramediterranean subhumid-humid areas of the Transverse Ranges biogeographical subsector (South Californian Ranges sector). They have their ecological optimum in the northern and winward marine slopes of the San Bernardino, San Gabriel and San Jacinto Mountains. These forests are mesophytic mixed fir forests, where we can found Pinus lambertiana, Pinus ponderosa var. ponderosa, Pinus coulteri or Calocedrus decurrens as common or dominant trees as well Quercus kelloggii, Castanopsis sempervirens or Ceanothus cordulatus in the understory. They form an upper belt referred to the sclerophyllous mesomediterranean subhumid forests of the Dryopterido-Quercetum agrifoliae (Quercion agrifoliae) forming wide ecotones with Pseudotsuga macrocarpa and Pinus coulteri as frequent trees mainly in depressions and compensed deep soils; whith this trees is commonly associated the eurioicous oak Quercus chrysolepis, forming some endemic mesic-hygrophilous permanent plant communities peculiar in the Transverse Ranges subsector territories; we think that these communities can constitute a particular association.

In the San Bernardino Mountains upward 2200-2300 m, in the oromediterranean belt and shady territories Pinus contorta var. murrayana forests replaces Querco kelloggii-Abietetum concoloris forests (Corallorhizo maculatae-Pinetum murrayanae inedit.); in the rest of stationss is frequent found the white fir forests mixed o replaced by Pinus jeffreyi, Pinus flexilis or Juniperus occidentalis var. australis forming some oromediterranean micro-mesoforests more xerophytic (with less snow pack accumulation and lower precipitation); this situations are closely related to the Sierra Nevada association Junipero australis-Pinetum jeffreyi belonging to Arctostaphylo patulae-Pinion jeffreyi alliance. In the San Bernardino, San Gabriel and San Jacinto supramediterranean level when the xericity and the continentality is increasing toward leeward slopes the mesophytic white fir forests are replaced gradually by Juniperus occidentalis var. australis and Pinus jeffreyi dry forests (Junipero australis-Pinetum jeffreyi "southcalifornian race") which when Pinus monophylla occurs and Pinus jeffreyi disappear as trees are replaced by the xeric continental forests of the Artemisio tridentatae-Juniperetea osteospermae (Great Basin region, Mohavian biogeographical province). Bioclimatical diagnosis: Ic 16-21, It < 200, Tp 900-1500, Io > 3.5.

Relevé typus: Rivas-Martínez reg. num. 1993b: 5, 12.06.1993. Site: San Bernardino County (California), San Bernardino Mountains, hill side in Deep Creek North Fork, between Arrowbear Lake and Snow Valley, 34º15'N-117º05'W, surface 400 m2, altitude 1950 m, orientation NW, inclination 25%. Physiognomy and habitat: Rocky Mountain white fir (Abies concolor) close macroforest, with Calocedrus decurrens, Pinus coulteri, Pinus ponderosa and Pinus lambertiana as big trees, and Quercus kelloggii, Castanopsis sempervirens and Pteridium aquilinum var. pubescens in the understory, 30-40 m high and 100 cm trunk diameter, deep mull cambisol on granit bedrock; adjacent edaphoxerophilous vegetation: Quercus chrysolepis-Pinus jeffreyi community. Stimate bioclimatic factors: Mediterranean pluvieasonal oceanic, semicontinental (Ic ~ 18.0), upper supramediterranean (Itc ~ 100, Tp ~ 1050), upper subhumid (Io ~ 5.0). Biogeographical location: Californian region, South Californian province, Transverse Ranges subsector, San Bernardino Mountains district. Floristic combination: Calocedro-Juniperetea jeffreyi characteristic species: 3 Abies concolor, 3 Quercus kelloggii, 2 Arctostaphylos patula subsp. patula, 2 Calocedrus decurrens, 2 Pinus coulteri, 2 Symphoricarpos mollis, 1 Arabis rectissima, 1 Castanopsis sempervirens, 1 Ceanothus cordulatus, 1 Pedicularis semibarbata, 1 Pinus lambertiana, 1 Pinus ponderosa var. ponderosa, + Stipa lemmonii; companion species: 2 Pteridium aquilinum var. pubescens, 1 Frangula californica, 1 Iris hartwegii subsp. australis.

Macrobosques climatófilos cerrados propios del piso supramediterráneo subhúmedo-húmedo del subsector biogeográfico de las Sierras Transversales (sector Serrano Californiano Meridional), que parecen tener su óptimo ecológico a barlovento y septentrión de las vertientes marítimas de las Montañas de San Bernardino, San Gabriel y San Jacinto. Se trata de abetales mixtos, mesofíticos en los que pueden llegar a ser frecuentes o incluso dominantes otro árboles como: Pinus lambertiana, Pinus ponderosa var. ponderosa, Pinus coulteri o Calocedrus decurrens, así como en el sotobosque Quercus kelloggii, Castanopsis sempervirens o Ceanothus cordulatus. Se sitúan altitudinalmente por encima de los bosques esclerófilos mesomediterráneos subhúmedos del Dryopterido-Quercetum agrifoliae (Quercion agrifoliae), formando amplios ecotonos, en los que pueden llegar a ser frecuentes en vaguadas y suelos profundos compensados Pseudotsuga macrocarpa y Pinus coulteri, a los que suele asociarse el encino eurioico Quercus chrysolepis, con el que forman comunidades permanentes meso-higrófilas endémicas del subsector de las Sierras Transversales, sin duda acreedoras del rango de asociación.

En las montañas de San Bernardino por encima de los 2200-2300 m, ya en el piso oromediterráneo, Querco kelloggi-Abietetum concoloris cede en las zonas umbrosas ante los bosques de Pinus contorta var. murrayana (Corallorhizo maculatae-Pinetum murrayanae inedit.) en tanto, que en el resto de las exposiciones se mezcla o es sustituido por Pinus jeffreyi, Pinus flexilis o Juniperus occidentalis var. australis, dando lugar a comunidades micro-mesoforestales oromediterráneas más xerofíticas (mayor innivación y menor precipitación en forma de lluvia), próximas a la asociación nevadense Junipero australis-Pinetum jeffreyi, ya perteneciente a la alianza Arctostaphylo patulae-Pinion jeffreyi. También en el piso supramediterráneo de San Bernardino, San Gabriel y San Jacinto al aumentar la xericidad y la continentalidad hacia sotavento, los abetales mesofíticos se transforman paulatinamente en bosques secos de Juniperus occidentalis var. australis y Pinus jeffreyi (Junipero australis-Pinetum jeffreyi "raza austrocaliforniana"), que a su vez con el ingreso de Pinus monophylla y la desaparición de Pinus jeffreyi conduce a los bosques xéricos continentales de la clase Artemisio tridentatae-Juniperetea osteospermae (Gran Cuenca, provincia biogeográfica Mojavense). Diagnosis bioclimática: Ic 16-21, It < 200, Tp 900-1500, Io > 3.5.

5. Arbuto menziesii-Lithocarpion densiflori alliancia nova hoc loco

Supramediterranean and upper mesomediterranean upper subhumid, humid and hyperhumid, hyperoceanic or euoceanic, closed climatophilous macro and megaforests, that can grow in all kinds of bedrocks except the ultramafic ones and form humus mull. They are widely distributed along North Californian biogeographical province, particularly in North Coastal and Klamath-Ciscascadian sectors, and in few places of the hyperhumid western valleys of Sierra Nevada subsector. On distinguish three large associations inside the Arbuto-Lithocarpion densiflori alliance. Two of them higly oceanic widely distributed in the North Californian Coastal sector: 5a. Lithocarpo densiflori-Pseudotsugetum menziesii (humid-hyperhumid supramediterranean inland of the Sequoia sempervirens megaforests), 5b. Lithocarpo densiflori-Sequoietum sempervirentis (mostly euhyperoceanic humid-hyperhumid with cool summers); the third association is distributed along the Klamath-Ciscascadian sector territories is more continental and drier: 5c. Arbuto menziesii-Pseudotsugetum menziesii. Bioclimatical diagnosis: Ic 5-19, Itc 120-250, Tp 1000-1700, Io > 4.5.

Typus nominis: Lithocarpo densiflori-Pseudotsugetum menziesii ass. nova hoc loco.

Characteristic species: Arbutus menziesii, Arctostaphylos columbiana, Cardamine californica var. sinuata, Cardamine cuneata, Castanopsis chrysophylla, Cornus glabrata, Iris douglasiana, Lithocarpus densiflorus, Polygala californica, Polystichum dudleyi, Polystichum imbricans subsp. imbricans, Sequoia sempervirens, Toxicodendron diversilobum (t), Umbellularia californica (t), Vancouveria planipetala.

Macro y megabosques climatófilos cerrados, supramediterráneo y mesomeditérraneo superior, subhúmedo superior, húmedo, hiperhúmedos, hiperoceánicos o euoceánicos, que se desarrollan sobre todo tipo de sustratos, excepto en los ultrabásicos y serpentínicos, y generan humus mull. Se hallan ampliamente representados en la provincia biogeográfica Californiana Septentrional sobre todo en los sectores Costero Septentrional y Klamath-Ciscascadas. También bastante localizados existen en algunos valles occidentales hiperhúmedos del subsector Sierra Nevada.

Se reconocen tres amplias asociaciones en el seno del Arbuto-Lithocarpion densiflori dos en el sector biogeográfico Californiano Costero Septentrional de exigencias muy oceánicas: 5a. Lithocarpo densiflori-Pseudotsetum menziesii (supramediterránea húmedo-hiperhúmeda que sustituye hacia el interior a los megabosques hiperoceánicos de Sequoia sempervirens), 5b. Lithocarpo densiflori-Sequoietum sempervirentis (euhiperoceánica húmedo-hiperhúmeda, de veranos muy frescos); y una tercera más continental y seca propia del sector Klamath-Ciscascadas, 5c. Arbuto menziesii-Pseudotsugetum menziesii. Diagnosis bioclimática: Ic 5-19, Itc 120-250, Tp 1000-1700, Io > 4.5.

5a. Lithocarpo densiflori-Pseudotsugetum menziesii associatio nova hoc loco

Climatophilous macro-megaforests with Pseudotsuga menziesii var. menziesii and Lithocarpus densiflorus as dominant trees; the understory is constituted by a dense wooded and shrubby formation. These forests have their optimum in the supramediterranean humid-hyperhumid, lower hyperoceanic and euoceanic belt of the californian North Coastal biogeografical sector. In California, when the oceanity and the fog are increasing toward the pacific coast areas these forests are replaced by Sequoia sempervirens forests which present a high summer mediterraneity (Ios2 < 0.5, Ios4 < 2.0) belonging to the mediterranean association Lithocarpo densiflori-Sequoietum sempervirentis; this phenomenum occurs in the coast toward south Patrick´s Point State Park (47º10'N); if the summer precipitation is higher and compensed (Ios2 > 0.7, Ios4 > 2.0), the megaforests of Sequoia sempervirens ("Redwood") grow in uppertemperate hyperoceanic bioclimate areas associated with the Tsugetalia heterohyllae characteristic trees (Tsuga heterophylla, Picea sitchensis, Thuja plicata) and we can distinguish other association: Tsugo heterophyllae-Sequoietum sempervirentis which have their optimum in the Redwood National Park and Forest territories; this last association is closely restricted to the mentioned coastal mountains rising the state of Oregon. Bioclimatical diagnosis: Ic 9-14, Tp 1100-1400, Io 5.5-15.0.

Relevé typus: Rivas-Martínez reg. num. 1995c: 15, 24.07.1995, achieved with Drs. F. Alcaraz, J. Delgadillo & M. Peinado. Site: Del Norte County (California), Six River National Forest in Smith River near Patrick Creek, 41º50'N-123º50'W, surface 500 m, altitude 250 m, orientation SE, inclination 25%. Physiognomy and habitat: Douglas-fir and tanoak macroforest with scrubs, trees and grass in the understory, 38-42 m high and 150 cm trunk diameter, mull cambisol, adjacent edaphoxerophilous rupicolous micro-mesoforest vegetation: Arbuto menziesii-Quercus chrysolepis community. Stimate bioclimate factors: Mediterranean pluviseasonal hyperoceanic-euoceanic (Ic ~ 11.0), lower supramediterranean (Itc ~ 180, Tp ~ 1350), lower humid (Io ~ 6.0). Biogeographical location: Californian region, North Californian province, North Coastal sector. Floristic combination: Calocedro-Pinetea jeffreyi characteristic species: 3 Lithocarpus densiflorus, 3 Pseudotsuga menziesii var. menziesii, 2 Arbutus menziesii, 2 Calocedrus decurrens, 2 Lonicera hispidula var. vacillans, 2 Polygala californica, 3 Quercus chrysolepis (t), 2 Frangula californica, 2 Toxicodendron diversilobum (t), 1 Lonicera interrupta, 1 Vancouveria planipetala, 1 Umbellularia californica (t), 1 Whipplea modesta, + Quercus garryana, + Pinus ponderosa var. ponderosa, + Polystichum imbricans subsp. imbricans; companion species: 3 Vaccinium ovatum, 2 Cinna latifolia, 1 Cytisus villosus, 1 Trientalis borealis subsp. latifolia.

Macro-megabosques climatófilos en el que son preponderantes Pseudotsuga menziesii var. menziesii y Lithocarpus densiflorus provisto de un sotobosque arbolado y arbustivo denso, que tienen su óptimo desarrollo en el piso supramediterráneo húmedo-hiperhúmedo, hiperoceánico inferior y euoceánico del sector biogeográfico Costero Septentrional californiano. En California, al aumentar la oceanidad y las nieblas hacia la costa pacífica estos bosques son desplazados por los de Sequoia sempervirens, que si tienen una acusada mediterraneidad estival (Ios2 < 0.5, Ios4 < 2.0) corresponden a la asociación mediterránea Lithocarpo densiflori-Sequoietum sempervirentis, lo que ocurre en el litoral al sur de Patrick"s Point State Park (47º10'N); en tanto que si la precipitación estival aumenta un poco y se compensa (Ios2 > 0.7, Ios4 > 2.0), los megabosques de Sequoia sempervirens ("Redwood") son ya de bioclima supratemplado hiperoceánico y se asocian a los elementos arbóreos de la Tsugetalia heterophyllae (Tsuga heterophylla, Picea sitchensis, Thuja plicata) originando la asociación Tsugo heterophyllae-Sequoietum sempervirentis que tiene su óptimo en Redwood National Park and Forest y que está localizada en dichas montañas costeras alcanzando apenas el estado de Oregón. Diagnosis bioclimática: Ic 9-14, Tp 1100-1400, Io 5.5-15.0.

5b. Lithocarpo densiflori-Sequoietum sempervirentis Delgadillo associatio nova

Climatophilous megaforests with Sequoia sempervirens ("redwood"), Lithocarpus densiflorus ("tanoak") and Pseudotsuga menziesii var. menziesii ("Douglas-fir") as dominant trees; these forests include a open shrubby and a dense grassy sciophilous understory. Their optimum exists in the supramediterranean humid-hyperhumid hyperoceanic areas of the californian North Coastal sector. When the mediterraneity disappear, that means the summer drought (Ios2 > 0.7, Ios4 > 2.0) the Sequoia sempervirens forests incorporate some supratemperate trees frequent in the Oregonian-Vancouverian Coastal sector territories: Tsuga heterophylla, Thuja plicata, etc. and they constitute the geovicariant north californian coastal association Tsugo heterophyllae-Sequoietum sempervirentis. When we go toward the south and east, the precipitation decreases and the continentality increases; then the Sequoia megaforests are replaced by the subhumid-humid Lithocarpo densiflori-Pseudotsugetum menziesii forests or by the dry-subhumid warmer Lithocarpo densiflori-Quercetum agrifoliae. We agree with the name and partially with the concept given by J. Delgadillo to this association in his PhD dissertation (1995); in consequence we validate here his proposal. Bioclimatical diagnosis: Ic 5-10, Tp 1200-1700, Io 7.0-15.0.

Relevé typus: Rivas-Martínez reg. num. 1995c: 6, 23.04.1995, achieved with Drs. F. Alcaraz, J. Delgadillo & M. Peinado. Site: Mendocino County (California), Jackson State Forest hills, near Whiskey Springs, 39º20'N-123º40'W, surface 400 m, altitude 240 m, orientation NW, inclination 10%. Physiognomy and habitat: Redwood, Douglas-fir and tanoak megaforest, with scrubs and grass in the understory, 46-54 m high and 170 cm trunk diameter, mull chromic andosol on basalt bedrock, adjacent edaphohygrophilous forest vegetation: Woodwardia fimbriata-Alnus rubra community. Stimate bioclimatic factors: Mediterranean pluviseasonal, euhyperoceanic (Ic ~ 6.0). lower supramediterranean (Tp ~ 1400), upper humid (Io ~ 9.0). Biogeographical location: Californian region, North Californian province, Californian North Coastal sector. Floristic combination: Calocedro-Pinetea jeffreyi characteristic species: 3 Sequoia sempervirens, 3 Lithocarpus densiflorus, 3 Pseudotsuga menziesii var. menziesii, 2 Arbutus menziesii, 2 Vancouveria planipetala, 2 Whipplea modesta, 1 Cardamine californica var. sinuata, 1 Iris douglasiana, 1 Lonicera hispidula var. vacillans, 1 Polygala californica, 1 Toxicodendron diversilobum, + Arctostaphylos columbiana, + Polystichum imbricans subsp. imbricans; companion species: 2 Galium trifidum, 2 Smilacina stellata, 2 Vaccinium ovatum, 2 Viola glabella, 1 Oxalis oregana, 1 Trillium ovatum, + Gaultheria shallon, + Genista monspessulana, + Pteridium aquilinum var. pubescens, + Trientalis borealis subsp. latifolia.

Megabosques climatófilos en el que son preponderantes Sequoia sempervirens ("redwood"), Lithocarpus densiflorus ("tanoak") y Pseudotsuga menziesii var. menziesii ("Douglas-fir"), provistos de un sotobosque de arbustos poco denso y otro herbáceo esciófilo denso; presentan su óptimo desarrollo en el piso supramediterráneo húmedo-hiperhúmedo hiperoceánico del sector biogeográfico Costero Septentrional Californiano. Al desaparecer la mediterraneidad, es decir, la sequía estival (Ios2 > 0.7, Ios4 > 2.0), los bosques de Sequoia sempervirens se enriquecen en los elementos supratemplados habituales del sector Costero Oregoniano-Vancouveriano: Tsuga heterophylla, Thuja plicata, etc. y pasan a constituir la asociación geovicariante costera norcaliforniana Tsugo heterophyllae-Sequoietum sempervirentis. Al desplazarnos hacia el sur y el este, desciende la precipitación y aumenta la continentalidad y con ello los megabosques de Sequoia son reemplazados por los subhúmedo-húmedos de Lithocarpo densiflori-Pseudotsugetum menziesii o por los seco-subhúmedos más cálidos del Lithocarpo densiflori-Quercetum agrifoliae. Al estar de acuerdo con el nombre y en una parte con el concepto dado a esta asociación por el Dr. J. Delgadillo en su tesis doctoral (1995) damos aquí validez a su propuesta. Diagnosis bioclimática: Ic 5-10, Tp 1200-1700, Io 7.0-15.0.

5c. Arbuto menziesii-Pseudotsugetum menziesii associatio nova

Climatophilous macroforests with Pseudotsuga menziesii var. menziesii, Calocedrus decurrens, Pinus lambertiana and Arbutus menziesii as dominant trees; in the wooded and shrubby understory are frequent, mainly in open areas, Quercus garryana and Quercus kelloggii. These forests have their optimum along the supramediterranean upper subhumid and humid, euoceanic o slightly semicontinental territories of the Klamath-Ciscascadas sector (North Californian biogeogrpahical province). In Ciscascadian subsector areas, in the upper supramediterranean level disappear Arbutus and Quercus and appear Pinus contorta var. murrayana and Pinus ponderosa var. ponderosa as common trees inside the forest, mainly after the fires; these pine species occurs in the forest open areas. If we ascend toward the semioromediterranean belt (orotemperate by compensation) these forests are replaced by the fir forests with several Abies species, often very hard to identify due the hybridizations: Abies procera, Abies magnifica, Abies concolor, Abies lowiana or even in higher altitudes Abies lasiocarpa associated with Tsuga mertensiana (Crater Lake National Park); these forests do not belong to the Calocedro decurrentis-Pinetea jeffreyi classis which appear, once more time, with their pine forests along the winward slopes of the Transcascadian subsector territories (Ceanotho velutini-Pinetum ponderosae). Bioclimatical diagnosis: Ic 14-19, Tp 1000-1500, Itc 120-210, Io 4.5-10.0.

Relevé typus: Rivas-Martínez reg. num. 1992e: 199, 31.08.1992. Site: Jackson County (Oregon), Rogue River National Forest, plain near Prospect and the junction with Mill Creek, 42º45'N-122º30'W, surface 400 m, altitude 750 m, orientation W, inclination 5%. Physiognomy and habitat: Douglas-fir (Pseudotsuga menziesii var. menziesii), Incense cedar (Calocedrus decurrens) and Madroño (Arbutus menziesii) macroforest with scrubs and grass in the understory, 30-35 m high and 120 cm trunk diameter, mull andosol on basalt bedrock, adjacent seral secundary microforest Quercus garryana-Arbutus menziesii community. Stimate bioclimatic factors: Mediterranean pluviseasonal oceanic, euoceanic (Ic ~ 16.0), lower supramediterranean (Itc ~ 160, Tp ~ 1300), lower humid (Io ~ 6.0). Biogeographical location: Californian region, North Californian province, Klamath-Ciscascadian sector, Ciscascadian subsector. Floristic combination: Calocedro-Pinetea jeffreyi characteristic species: 4 Pseudotsuga menziesii var. menziesii, 3 Calocedrus decurrens, 2 Arbutus menziesii, 2 Hieracium albiflorum, 2 Quercus garryana, 2 Toxicodendron diversilobum (t), 1 Castanopsis sempervirens, 1 Pinus lambertiana, 1 Pinus ponderosa var. ponderosa, 1 Quercus kelloggii, 1 Symphoricarpos mollis, + Ceanothus velutinus, + Chimaphila umbellata; companion species: 1 Adenocaulon bicolor, 2 Elymus glaucus, 2 Hypnum cf. cupressiforme, 2 Mahonia aquifolium, 1 Amelanchier alnifolia, 1 Holodiscus discolor, 1 Pteridium aquilinum var. pubescens, + Rubus laciniatus.

Macrobosques climatófilos en los que suelen ser preponderantes Pseudotsuga menziesii var. menziesii, Calocedrus decurrens, Pinus lambertiana y Arbutus menziesii, provistos de un sotobosque de arbolillos y arbustos donde son frecuentes, sobre todo en etapas aclaradas, Quercus garryana y Quercus kelloggii. Presentan su óptimo en el piso supramediterráneo subhúmedo superior y húmedo, euoceánico o ligeramente semicontinental en el sector Klamath-Ciscascadas de la provincia biogeográfica Californiana Septentrional. En el subsector de Ciscascadas, en el horizonte superior supramediterráneo desaparecen Arbutus y Quercus al tiempo que se hacen más frecuentes en el bosque, sobre todo tras los fuegos, Pinus contorta var. murrayana y Pinus ponderosa var. ponderosa que suelen ocupar las estaciones más abiertas. Al entrar en el piso semioromediterráneo (orotemplado por compensación) aparecen los bosques de abetos con diversas especies de Abies a veces de difícil determinación por sus introgresiones: Abies procera, Abies magnifica, Abies concolor, Abies lowiana o incluso a más altitud Abies lasiocarpa con el que llega Tsuga mertensiana (Crater Lake National Park), que ya no pertenecen a la clase Calocedro decurrentis-Pinetea jeffreyi cuyos bosques de pinos vuelven a aparecer a barlovento en el subsector Transcascadas (Ceanotho velutini-Pinetum ponderosae). Diagnosis bioclimática Ic: 14-19, Tp 1000-1500, Itc 120-210, Io 4.5-10.0.

Acknowledgements: We thanks the Spanish Universidad Complutense (Gregorio del Amo Program) and Ministerio de Educación y Ciencia (Research Stays in Foreign Countries Program) their financial help, in order to elaborate a syntaxonomical approach of the Californian natural potential vegetation communities during 1996. Moreover to the University of California (Environmental Horticulture, Davis) and specially to Professor M. G. Barbour for their collaboration, facilities and field works supplies, and finally to M.P. Rodríguez Rojo for their collaboration and help in the Californian field trips.

Table 7. Relations between vegetation associations of Calocedro decurrentis-Pinetea jeffreyi classis, and the sectors and subsectors territories of Californian biogeographical region. 1. North Californian province: 1aa. Klamath, 1ab. Ciscascadian, 1ba. Sierra Nevada, 1bb. Transcascadian, 1c. North Coastal, 1da. Sacramento Valley, 1db. San Joaquin Valley, 1dc. Central Coastal Ranges. 2. South Californian province: 2aa. Transverse Ranges, 2ab. North Baja California Ranges, 2ba. South Coastal, 2bb. Channel Islands.

Table 8. Bioclimatic indices ranges in natural potential vegetation alliances of Californian biogeographical region. Are not included the values of edaphoxerophilous topographic vegetation. Ic = Continentaly index, Itc = Compensate thermicity index, Tp = Sum of positive temperature of the year, Io = Ombrothermic index.

Table 9. Relation between the natural potential vegetation alliances of Calocedro-Pinetea jeffreyi and bioclimatic belt in Californian biogeographical region. Ombrotypes: 5. Dry (Io 2.0-3.0), 6. Subhumid (Io 3.0-5.5), 7. Humid (Io 5.5-11.0), 8. Hyperhumid (Io 11.0-22.0). Potential vegetation: C = climatophylous, X = topographic edaphoxerophylous, M = ultramafic edaphoxerophylous.

Table 10. Relation between phytosociological vegetation alliances and bioclimatical ombro-thermic territories in Californian biogeographical region. Heteromelo arbutifoliae-Quercetea agrifoliae: 1. Quercion agrifoliae, 2. Quercion douglasio-wislizenii, 3. Quercion frutescenti-dumosae, 4. Quercion duratae, 5. Malosmion laurinae, 6. Agavion shawii, 7. Adenostomion fasciculati. Calocedro decurrentis-Pinetea jeffreyi: 8. Arctostaphylo patulae-Pinion jeffreyi, 9. Querco vaccinifoliae-Pinion jeffreyi, 10. Querco kelloggii-Abietion lowianae, 11. Abietion magnificae, 12. Arbuto menziesii-Lithocarpion densiflori. Ombrotypes: xeric (Io < 2.0), pluviseasonal (Io > 2.0).

Table 11. Relation between phytosociological vegetation alliances, sectors and provinces of Californian biogeographical region. Heteromelo arbutifoliae-Quercetea agrifoliae: 1. Quercion agrifoliae, 2. Quercion douglasio-wislizenii, 3. Quercion frutescenti-dumosae, 4. Quercion duratae, 5. Malosmion laurinae, 6. Agavion shawii, 7. Adenostomion fasciculati. Calocedro decurrentis-Pinetea jeffreyi: 8. Arctostaphylo patulae-Pinion jeffreyi, 9. Querco vaccinifoliae-Pinion jeffreyi, 10. Querco kelloggii-Abietion lowianae, 11. Abietion magnificae, 12. Arbuto menziesii-Lithocarpion densiflori.

Table 12. Approximates relations between classes and phases communities of Californian upland forests and woodlands (Barbour, 1988) and their respectives phytosociological Braun-Blanquet syntaxa.