DISCUSSION AND RESULTS. DESCRIPTION OF PLANT COMMUNITIES

5d. Tsugo heterophyllae-Sequoietum sempervirentis associatio nova hoc loco

Hyperoceanic Temperate (euhyperoceanic); mesotemperate; submediterranean; humid to lower hyperhumid; redwood (Sequoia sempervirens) diverse climactical coniferous megaforests spreading into Oregonian Coastal Subsector territories (Redwood National Park District) of the Oregonian-Vancouverian Coastal Sector.

Bioclimatic diagnosis: Ic 5-7, Io 7.0-14.0, Itc 200-270, Tp 1200-1400, Tps 360-450, Tmin > 5, m > 2, Ios2 < 2.5. [Teho-Mte-Hum, Hhu-Sbm].

Table 18 shows seven relevés from the North-Western California territories sampled in several great groves of Humboldt and Del Norte Counties (Redwood National Park, and Jedediah Smith and Coast Redwood State Parks). Redwood (Sequoia sempervirens) is probably the most impressive tree in North America; specimens with 80 m high and more than 4 m of trunk diameter are common in the Redwood National Park District areas of the Oregonian-Vancouverian Coastal Subsector. Other big conifers but less frequent in these forests are Tsuga heterophylla, Pseudotsuga menziesii var. menziesii, Picea sitchensis and Thuja plicata. Among the understory we could mentione as common species the following: Disporum smithii, Gaultheria shallon, Maianthemum dilatatum, Oxalis oregana, Polystichum munitum, Trillium ovatum, Vaccinium ovatum and Vancouveria hexandra. As differential species from the rest of the associations of Tsugion heterophyllae alliance, which do not exist or are uncommon species within Sequoia sempervirens forests it could be mentioned: Achlys triphylla, Cornus canadensis, Linnaea americana, Oplopanax horridus, Rubus pedatus, Tiarella trifoliata var. trifoliata and Tiarella trifoliata var. unifoliata.

Type relevé (holotypus): Table 18, relevé n. 2. Rivas-Martínez reg. 1992e: 186. 29.08.92. Site: California: Del Norte Co. Crescent City. Redwood National Park, Ruth Perry Hutton Grove. 41º44'N-124º08'W. 240 m, NE, 5%, 80 m, 300 cm, 2000 m2. Physiognomy and habitat: Mature redwood (Sequoia sempervirens), western red cedar (Thuja plicata) and western hemlock (Tsuga heterophylla) megaforest. Estimated bioclimatic factors: Hyperoceanic Temperate (Ic ~ 6.0), upper mesotemperate (Itc ~ 220), submediterranean (Ios2 ~ 1.4), lowerhyperhumid (Io ~ 14.0), Positive Summer Temperature Tps ~ 420. Biogeographic location: Rocky Mountain Region, North-Western Pacific Subregion, Cascade Province, Oregonian-Vancouverian Coastal Sector, Oregonian Coastal Subsector, Redwood National Park Distrit. Floristic combination: Linnaeo-Piceetea characteristic species, trees: + Acer circinatum, 1 Pseudotsuga menziesii, 5 Sequoia sempervirens, 1 Thuja plicata, 2 Tsuga heterophylla. Others: + Adenocaulon bicolor, 1 Asarum caudatum, 1 Athyrium filix-femina var. cyclosorum, 1 Disporum smithii, 1 Dryopteris expansa, 1 Frangula purshiana, + Galium trifidum, 2 Gaultheria shallon, + Luzula parviflora subsp. parviflora, 2 Maianthemum dilatatum, + Osmorhiza purpurea, 4 Oxalis oregana, 4 Polystichum munitum, 1 Rhododendron macrophyllum, 1 Rosa woodsii var. ultramontana, + Stachys ciliata, + Trientalis latifolia, 1 Trillium ovatum, 2 Vaccinium ovatum, 2 Vaccinium parvifolium, 3 Vancouveria hexandra. Companion species: 2 Blechnum spicant, 2 Eurhynchium oreganum, 1 Polypodium glycyrrhiza, + Pteridium aquilinum var. pubescens.

Table 18
5d. Tsugo heterophyllae-Sequoietum sempervirentis
(Tsugion heterophyllae, Tsugetalia mertensiano-heterophyllae)

Other species. Trees: Alnus rubra + in 1, 3 and 5. Acer circinatum + in 2, 2 in 4. Characteristic species: Adenocaulon bicolor + in 2, 3, 4 and 7. Rosa ultramontana 1 in 2 and 3. Maianthemum stellatum + in 4 and 6. Rubus ursinus 1 in 1. Frangula purshiana 1, Vaccinium parvifolium 2 in 2. Vaccinium ovalifolium 1 in 3. Orthilia secunda 1 in 4. Clintonia uniflora 1, Goodyera oblongifolia + in 5. Dicentra formosa + in 6. Tolmiea menziesii +, Mitella caulescens +, Oemleria cerasiformis +, Viola glabella + in 7. Companion species: Claytonia sibirica + in 1, 1 in 5, 2 in 7. Bromus vulgaris + in 3 and 4, 2 in 7. Pteridium pubescens + in 2, 3 and 7. Carex leptopoda + in 3, 5 and 6. Iris douglasiana 1 in 5, + in 6 and 7. Polypodium glycyrrhiza 1 in 1 and 2. Trisetum cernuum 1 in 3 and 4. Climacium dendroides + in 3, 1 in 7. Brachythecium frigidum 1 in 5 and 6. Polytrichum commune 1 in 5 and 6. Plagiothecium undulatum 1 in 5 and 6. Cystopteris fragilis + in 5 and 6. Cytisus scoparius +, Hedera helix + in 1. Adiantum aleuticum + in 4. Whipplea modesta 1 in 6. Carex obnupta 1, Lysichiton americanus +, Poa kelloggii + in 7.

Localities: 1. California: Humboldt Co. Trinidad-Patrick"s Point. Patrick"s Point Drive. 41º06'N-124º09'W. N, 20%, 60 m, 180 cm, 4000 m2 (reg. 1998a: 8). 2. California: Del Norte Co. Crescent City, Redwood National Park, Ruth Perry Hutton Grove. 41º44'N-124º08'W. NE, 5%, 80 m, 300 cm, 2000 m2, holotypus ass. (reg. 1992e: 186). 3. California: Del Norte Co. Redwood National Park. 41º44'N-124º06'W. E, 10%, 70 m, 300 cm, 4000 m2 (reg. 1998a: 13). 4. California: Del Norte Co. Crescent City. Jedediah Smith Redwoods State Park. 41º48'N-123º57'W. NW, 10%, 65 m, 300 cm, 2000 m2 (reg. 1998a: 14). 5. California: Del Norte Co. Del Norte Coast Redwoods State Park. 41º43'N-124º05'W. SW, 5%, 80 m, 400 cm, 4000 m2 (reg. 1998a: 10). 6. California: Del Norte Co. Del Norte Coast Redwoods State Park. 41º43'N-124º04'W. W, 20%, 80 m, 400cm, 4000 m2 (reg. 1998a: 11). 7. California: Humboldt Co. Prairie Creek Redwoods State Park. Redwood Creek Trail. 41º24'N-124º02'W. S, 20%, 70m, 300 cm, 4000 m2 (reg. 1998a: 9). 8. Synthesized table.

5e. Gaultherio shallonis-Pseudotsugetum menziesii associatio nova hoc loco

Oceanic Temperate (euoceanic); meso-, supra-, and lower orotemperate; mainly submediterranean; upper subhumid to humid; climactical coniferous, macro- and megaforests, usually dominated by coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) and other conifer trees such as western red cedar (Thuja plicata) and western hemlock (Tsuga heterophylla), which cover broad areas throughout the Oregonian-Vancouverian Coastal and Cascade Ranges Sectors territories. These forests grow on andosols, luvisols, cambisols or cambic podzols and their secondary deciduous forests are organized by red adler (Alnus rubra) belonging to Aceri macrophylli-Alnetum rubrae association (Alno rubrae-Populion trichocarpae, Alno rubrae-Populetalia trichocarpae).

Bioclimatic diagnosis: Ic 11-18, Io 5.6-12.0, Itc < 210, Tp 600-1400, Tps 380-550, Tmin < 5, m < 2, Ios2 <2.5. [Teoc-mte, Ste, Ote-Ushu, Hum-Sbm].

Table 19 shows 20 relevés sampled throughout the British Columbia, Washington and Oregon territories. Coastal Douglas fir (Pseudotsuga menziesii var. menziesii) is usually the dominant tree and as codominants we can mentine Thuja plicata and Tsuga heterophylla. Acer circinatum, Acer macrophyllum and Alnus rubra are also common small trees in the undercanopy.

In the understory the most frequent plants are Achlys triphylla, Chimaphila umbellata subsp. occidentalis, Polystichum munitum, Trientalis borealis subsp. latifolia and Vaccinium parviflorum. Within the most significant differential species in front to the more continental (subcontinental) and usually driest geovicariant association Abieti grandis-Pseudotsugetum menziesii we can remark some trees such as Acer macrophyllum and Alnus rubra, and some understory plants such as Frangula purshiana, Gaultheria shallon, Menziesia ferruginea, Polystichum munitum, Tiarella trifoliata var. trifoliata, Vaccinium membranaceum and Vaccinium parvifolium. Conversely, we could use as differential species Abies grandis, Larix occidentalis, Chimaphila menziesii, Paxistima myrsinites and Rubus lasiococcus.

Table 19
5e. Gaultherio shallonis-Pseudotsugetum menziesii
(Tsugion heterophyllae, Tsugetalia mertensiano-heterophyllae)

Other species. Trees: Taxus brevifolia 3 in 2, 1 in 6 and 14, + in 17. Characteristics species: Asarum caudatum 2 in 5 and 20, + in 9 and 18, 1 in 15. Disporum oreganum 1 in 5 and 16, + in 10, 2 in 11 and 17. Disporum smithii + in 9, 15, 18, 19 and 20. Menziesia ferruginea 2 in 3, 1 in 6, 8 in 10. Cornus canadensis 2 in 3 and 7, 3 in 10, 1 in 20. Symphoricarpos laevigatus + in 2, 1 in 10, 18 and 19. Chimaphila menziesii 1 in 3 and 19, + in 4 and 15. Luzula parviflora + in 6, 15 and 19, 1 in 13. Maianthemum amplexicaule 1 in 9 and 19, + in 11 and 17. Oplopanax horridus + in 11 and 16, 1 in 13, 2 in 17. Cornus sericea + in 14 and 15, 2 in 19, 1 in 20. Gymnocarpium dryopteris 1 in 3 and 11, + in 10. Coralorhiza mertensiana 1 in 4 and 16, + in 8. Listera cordata + in 4 and 19, 2 in 20. Dryopteris expansa + in 5 and 17, 1 in 6. Holodiscus discolor 1 in 8, + in 9 and 17. Tellima grandiflora 2 in 8, + in 13, 1 in 20. Vaccinium membranaceum 1 in 10, + in 15 and 18. Viola orbiculata 2 in 12, 1 in 15 and 18. Cornus nuttallii + in 13, 16 and 18. Athyrium cyclosorum 2 in 13, 1 in 17. Rosa ultramontana 2 in 2 and 19. Monotropa uniflora + in 4 and 19. Oxalis oregana 2 in 7 and 9. Rubus strigosus + in 10, 1 in 11. Pyrola picta 1 in 10 and 19. Orthilia secunda 1 in 12, + in 14. Rubus nivalis 2 in 12 and 15. Viola sempervirens 1 in 13 and 16. Tolmiea menziesii 2 in 13, 1 in 17. Chrysolepis minor + in 14 and 18. Lonicera conjugialis + in 17 and 20. Listera caurina 1, Rosa nutkana 1, Lilium columbianum +, Lycopodium annotinum + in 2. Dicentra formosa 1 in 5. Actaea arguta 1 in 6. Disporum trachycarpum + in 7. Mitella breweri + in 9. Ribes laxiflorum + in 11. Campanula scouleri 1 in 12. Ribes lacustre 2, Rubus spectabilis + in 13. Oemleria cerasiformis 1 in 17. Allotropa virgata + in 19. Stellaria crispa 2, Ribes montigenum 1 in 20. Companion species: Athyrium americanum 1 in 3 and 10, 1 in 12. Corylus californica 1 in 5, 7 and 16, + in 9, 18 and 20. Bromus vulgaris 1 in 14, 2 in 12, 1 in 13, 15 and 17. Rhytidiadelphus triquetrus 2 in 1, 16 and 18, 1 in 19. Climacium dendroides 2 in 9 and 19, 1 in 11, 3 in 13. Fragaria platypetala + in 3 and 18, 1 in 14. Blechnum spicant 2 in 10, + in 14, 1 in 17. Plagiothecium undulatum 1 in 4, 2 in 8. Whipplea modesta 1 in 12, 2 in 15. Polypodium glycyrrhiza 1 in 8. Sanicula crassicaulis 2 in 9. Dryopteris carthusiana 2 in 13.

Localities: 1. British Columbia: Vancouver Island, Victoria, Goldstream River. 48º25'N-123º22'W. NE, 20%, 15 m, 130 cm, 1000 m2 (reg. 1992e: 122). 2. Washington: Clallam Co. Olympic Mountains, Olympic National Park, Hurricane Ridge Road-Hurricane Hill, Lake Creek. 48º02'N-123º24'W. S, 25%, 50 m, 100 cm, 2000 m2 (reg. 1998a: 68). 3. Washington: Whatcom Co. Newhalem, North Cascades National Park. 48º41'N-121º16'W. N, 10%, 45 m, 110 cm, 2000 m2 (reg. 1998b: 86). 4. Washington: Clallam Co. Olympic Mountains, Olympic National Park, Hurricane Ridge Road-Hurricane Hill, Lake Creek. 48º02'N-123º24'W. S, 40%, 50 m, 100 cm, 2000 m2 (reg. 1998a: 67). 5. Washington: Cayouse Valley, Cowlitz River. W, 5%, 50 m, 120 cm, 2000 m2. (reg. 1996: 92). 6. Washington: Pierce Co. Carbonado-Fairfax, Carbon River, West side of Mount Rainier to Mowich Lake. 47º03'N-122º02'W. E, 35%, 35 m, 60 cm, 2000 m2 (reg. 1997: 50). 7. Oregon: Hood River Co. Mt. Hood National Forest. Lolo Pass, Elk Creek. 45º26'N-121º47'W. W, 20%, 55 m, 150 cm, 2000 m2 (reg. 1995: 112). 8. British Columbia: Squamish West. 49º44'N-123º08'W. W, 15%, 50 m, 100 cm, 2000 m2 (reg. 1995: 114). 9. Oregon: Douglas Co. Idleyld Park-Steamboat, North Umpqua Hwy. Honey Creek. 43º18'N-122º56'W. S, 20%, 45 m, 130 cm, 2000 m2 (reg. 1998a: 32). 10. British Columbia. Vancouver Island, Lady Falls, Strathcona Provincial Park. 49º52'N-125º50'W. N, 30%, 40 m, 130 cm, 2000 m2 (reg. 1997: 18). 11. British Columbia: Vancouver Island, Campbell River, Elk Falls Provincial Park. 50º00'N-125º30'W. N, 20%, 50 m, 200 cm, 2000 m2 (reg. 1997: 16). 12. Oregon: Klamath Co. Deschutes National Forest. Odell Lake, southwestern side of Willamette Pass. 43º35'N-122º01'W. SW, 10%, 50 m, 130 cm, 2000 m2 (reg. 1998b: 41). 13. Washington: Skagit Co. Mt. Baker-Snoqualmie National Forest. Rockport, Rockport State Park,. 48º29'N-121º36'W. S, 10%, 60 m, 230 cm, 4000 m2 (reg. 1998b: 85). 14. Oregon: Lane Co. Willamette National Forest, between Odell Lake and Heather, northwestern side of Willamette Pass. 43º36'N-122º02'W. NW, 5%, 50 m, 120 cm, 2000 m2 (reg. 1998b: 42). 15. Oregon: Lane Co. Willamette River North Fork. 43º46'N-122º29'W. SW, 10%, 55 m, 180 cm, 2000 m2 (reg. 1998b: 45). 16. Washington: Lewis Co. Gifford Pinchot National Forest, North Fork Cispus River. 46º27'N-121º48'W. W, 5%, 55 m, 160 cm, 4000 m2 (reg. 1998b: 81). 17. Washington: Clallam Co. Port Angeles, Olympic Mountains, Olympic National Park, White Creek. 48º05'N-123º25'W. N, 25%, 50 m, 80 cm, 2000 m2 (reg. 1998a: 70). 18. Oregon: Lane Co. Lost Creek White Branch. 43º56'N-122º51'W. N, 10%, 50 m, 120 cm, 2000 m2 (reg. 1998b: 49). 19. Oregon: Douglas Co. Tokettee Falls-Clearwater, Toketee Falls Trail. 43º15'N-122º25'W. N, 20%, 50 m, 150 cm, 2000 m2 (reg. 1998a: 33). 20. Oregon: Marion Co. Between New Idanha and Marion Forks, Santiam Hwy. McCoy Creek Road. 44º41'N-122º03'W. W, 5%, 70 m, 150 cm, 2000 m2, holotypus ass. (reg. 1998a: 44). 21. Synthesized table.

Type relevé (holotypus): Table 19, relevé n. 20. Rivas-Martínez reg. 1998a: 44. 12.06.98, made with Drs. Costa, Ladero & Sánchez-Mata. Site: Oregon: Marion Co. Between New Idanha and Marion Forks. Santiam Hwy., McCoy Creek Road. 44º41'N-122º03'W. 590 m, W, 5%, 70 m, 150 cm, 2000 m2. Physiognomy and habitat: Mature coastal Douglas fir (Pseudotsuga menziesii var. menziesii), western hemlock (Tsuga heterophylla) and western red cedar (Thuja plicata) megaforest. Estimated bioclimatic factors: Oceanic Temperate (Ic ~ 16), lower supratemperate (Itc ~ 160), upper humid (Io ~ 10.0), Positive Summer Temperature Tps ~ 520. Biogeographic location: Rocky Mountain Region, North-Western Pacific Subregion, Cascade Province, Cascade Ranges Sector, Oregonian Cascade Subsector. Floristic combination: Linnaeo-Piceetea characteristic species, trees: 2 Acer circinatum, + Acermacrophyllum, 5 Pseudotsuga menziesii, 1 Thuja plicata, 1 Tsuga heterophylla. Others: 2 Achlys triphylla, + Adenocaulon bicolor, 2 Anemone deltoidea, 2 Asarum caudatum, 1 Chimaphila umbellata subsp. occidentalis, 1 Clintonia uniflora, 1 Cornus canadensis, 1 Cornus sericea subsp. sericea, + Disporum smithii, + Frangula purshiana, + Galium triflorum, 2 Gaultheria shallon, 2 Linnaea americana, 2 Listera cordata, + Lonicera conjugialis, 4 Mahonia nervosa, 2 Maianthemum stellatum, + Polystichum munitum, 1 Pyrola asarifolia, 1 Rhododendron macrophyllum, 1 Ribes montigenum, + Rubus parviflorus, 1 Tellima grandiflora, + Tiarella unifoliata, 1 Trillium ovatum, 1 Vaccinium ovalifolium, 2 Vaccinium parvifolium, 2 Vancouveria hexandra. Companion species: + Corylus cornuta subsp. californica, 3 Eurhynchium oreganum, 2 Hylocomium splendens, + Mycelis muralis, 1 Pteridium aquilinum var. pubescens.