North American boreal and western temperate forest vegetation

Salvador Rivas-Martínez, Daniel Sánchez-Mata & Manuel Costa

Itinera Geobotanica 12:5-316 (1999)


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Description of Plant Communities: Ledo decumbentis-Piceion marianae

4. Ledo decumbentis-Piceion marianae Peinado, Aguirre & Cruz 1998 em. hoc loco

[Ledo decumbentis-Piceion marianae Peinado, Aguirre & Cruz in Plant Ecology 137: 180. 1998, Shepherdio canadensis-Piceion glaucae Peinado, Aguirre & Cruz 1998 in Plant Ecology 137: 167. 1998 (syntax. syn., art. 25) (holotype: Hypno procerrimi-Piceetum glaucae Hoefs, Cowan & Krajina ex Peinado, Aguirre & Cruz in Plant Ecology 137: 167. 1998), Piceion marianae Wali & Krajina ex Peinado, Aguirre & Cruz in Plant Ecology 137: 196. 1998 (syntax. syn., art. 25) (holotype: Corno canadensis-Piceetum marianae Wali & Krajina ex Peinado, Aguirre & Cruz in Plant Ecology 137: 196. 1998, art. 37), Mertensio paniculatae-Piceion glaucae nobis ined.]

Typus nominis: Rubo chamaemori-Piceetum marianae Peinado, Aguirre & Cruz in Plant Ecology 137: 182. 1998.

North American Continental Boreal (eucontinental and subcontinental); meso- and supraboreal (locally Temperate hemiboreal as extrazonal in the Northern Rocky Mountain Province and the Columbia Mountains Sectors territories: Rubo chamaemori-Piceetum marianae, in boggy soils); dry to lower humid (exceptionally upper semiarid); coniferous micro- and mesoforests which represent the climatic or edaphic climax of black and white spruce (Picea mariana, Picea glauca var. glauca) and tamarack (Larix laricina) and, in the Cassiar Mountains Subsector as northern boundary of the species, also lodgepole pine (Pinus contorta var. latifolia) appears as pyrogenic tree growing on regosols. Sometimes in burned or disturbed forests, the conifers are also mixed with deciduous ligth-woody trees such as Alaska birch (Betula neoalaskana), quacking aspen (Populus tremuloides) and balsam poplar (Populus balsamifera subsp. balsamifera). The coniferous forests of this taiga formation grow on zonal and azonal soils such as podzols, regosols or histosols, with dystric, gleyic, stagnic or gelic character, throughout the Yukonian-Alaskan Province territories.

Bioclimatic diagnosis: Ic 22-46, Io 1.8-10.0, Tp 380-640, Tps 300-450, Tmin < -9º, m < -14º. [Boco, Bosc, Teco-Mbo, Sbo, Ote-Usar, Dry, Shu, Hum].

We distinguish within the alliance Ledo-Pinion marianae four different associations (figures 16, 17 and 18): 3a. Rubo chamaemori-Piceetum marianae (meso- and supraboreal, continental and subcontinental, dry to humid, growing on boggy soils throughout the Yukonian-Alaskan Province territories and locally, as relict and edaphophilous extrazonal community, in Canadian Rockies, Fraser Interior Plateau and Canadian Mountains Sectors), 3b. Piceetum glauco-marianae (meso- and supraboreal, continental and subcontinental, subhumid to humid, growing on podzol soils throughout the Yukonian-Alaskan Province territories), 3c. Hypno procerrimi-Piceetum glaucae (meso- and supraboreal, continental xeric, semiarid to dry steppic, growing on haplic gleyic or gelic podzol soils throughout the Cassiar Mountains, Boreal Xeric Alaskan and Great Bear Lake Subsectors of the Yukonian-Alaskan Province), 3d. Pulsatillo multifidae-Pinetum latifoliae (meso- and supraboreal, continental, dry steppic, pyrogenic, growing on regosols or haplic podsols throughout the Cassiar Mountains Subsector areas of the Yukonian-Alaskan Province).

Characteristic species: Arctagrostis latifolia subsp. arundinacea, Artemisia laciniata, Artemisia tilesii subsp. elatior, Betula xeastwoodiae (B. glandulosa x occidentalis), Betula xdutillyi (B. glandulosa x minor), Carex lugens, Corydalis pauciflora, Gentianella propinqua, Mertensia paniculata var. alaskana, Mertensia paniculata var. eastwoodiae, Mertensia paniculata var. paniculata, Petasites frigidus var. nivalis, Polygonum alaskanum, Salix arbusculoides, Senecio lugens.

4a. Rubo chamaemori-Piceetum marianae Peinado, Aguirre & Cruz 1998 em. hoc loco

[Rubo chamaemori-Piceetum marianae Peinado, Aguirre & Cruz in Plant Ecology 137: 182. 1998, Larici laricinae-Piceetum marianae Looman ex Peinado, Aguirre & Cruz in Plant Ecology 137: 184. 1998 (art. 25), Carici lugentis-Piceetum marianae nobis ined.]

Continental and Subcontinental Boreal; meso- and supraboreal; dry to humid: black spruce (Picea mariana) micro- or mesoforests growing on bog-peaty soils (fibric and gelic histosols) and gleyic or gelic podzols with histic H horizon throughout the Yukonian-Alaskan Province territories. In the northern hemiboreal territories of Northern Rocky Mountains and Cascade Provinces (Omineca Mountains, Nechako-Fraser Plateau and Columbia Mountains Subsectors) it is possible also to recognize this forest association, as local relictic and edapho-hygrophilous extrazonal communities growing on boggy soils in flat humid stations, and become frequent some Picea mariana microforests with understory organized by Betula glandulosa, Salix arbusculoides, Ledum groenlandicum, Rubus chamaemorus and carpets of Sphagnum and other bryophytes.

Bioclimatic diagnosis Ic 23-46, Io 1.8-10.0, Tp 380-630, Tps 300-450, Tmin < -9º, m < -14º. [Bosc, Boco, Teco-Mbo, Sbo, Ote-Usar, Dry, Shu, Hum].

Table 10 gives ten relevés from Alaska and Yukon Territory sampled throughout the meso- and supraboreal continental areas, belonging to the Susitna, Tanana, Stewart, McMillan, Teslin and middle and upper Yukon basin river territories. In this wooded association on gleyic, gelic and histic wet spongy peaty soils, the commonest trees are short black spruces (Picea mariana), with a dense chamaephytic and bryophytic understory, organized by Vaccinium vitis-idaea subsp. minus, Vaccinium uliginosum subsp. minus, Empetrum nigrum subsp. hermaphroditum, Ledum groenlandicum, Salix arbusculoides, Salix glauca var. acutifolia, Betula glandulosa, Rubus chamaemorus, Arctostaphylos rubra, etc. Among the most diagnostic plants of Rubo-Piceetum marianae are the Sphagnum species (Sphagnum magellanicum, Sphagnum angustifolium, Sphagnum fuscum, etc.), Vaccinium oxycoccos and Carex lugens. Carex lugens is a good territorial characteristic species, but our previous non-published name Carici lugentis-Piceetum marianae fails following the current CPN (publication and priority rules).

 Table 10
4a. Rubo chamaemori-Piceetum marianae

(Ledo-Piceion marianae
, Gaultherio-Piceetalia)

Altitude (1=10 m) 102 103 60 79 80 60 80 50 49 82 74
Number of species 16 17 18 19 19 20 20 22 23 23 20
Ordinal number 1 2 3 4 5 6 7 8 9 10 11
Trees:
Picea mariana 4 4 5 5 4 5 5 3 3 4 V
Picea glauca 1 1 . . . . . 2 1 . III
Characteristic species:
Vaccinium minus 3 3 4 2 1 1 3 3 2 3 V
Ledum groenlandicum 2 3 4 3 2 3 4 4 4 3 V
Salix arbusculoides 2 2 1 2 1 2 1 1 1 1 V
Carex lugens 2 1 1 2 2 3 3 2 1 3 V
Vaccinium alpinum 4 2 1 3 4 3 . 2 3 3 V
Empetrum hermaphroditum 2 2 3 2 3 . 2 3 . 2 IV
Rubus chamaemorus . 2 3 1 1 1 . 2 1 1 IV
Arctagrostis arundinacea . 1 1 1 . 1 2 1 2 1 IV
Betula glandulosa 2 . . 2 2 . 3 1 4 2 IV
Salix acutifolia 2 . . 2 . 2 2 2 2 3 IV
Petasites nivalis . 1 1 1 . . 1 . 2 1 III
Arctostaphylos rubra . . . 3 1 3 1 3 . 2 III
Pentaphylloides floribunda . . . 2 . 1 1 2 1 1 III
Saussurea angustifolia . . . 1 2 + . . + + III
Rosa sayi 1 . + . . . 1 + . . III
Vaccinium oxycoccos . 2 2 . 2 2 . . . . III
Equisetum scirpoides . . . 1 1 + 1 . . . III
Mertensia paniculata . . . 1 . + + .   + III
Geocaulon lividum . . 2 . + . + . . . II
Lupinus arcticus . . . . . 1 . 1 . 2 II
Companion species:
Bryophyta gen. et sp. pl. 5 5 4 5 5 5 4 5 4 5 V
Cladina rangiferina 3 2   . 2 2 3 . . . III
Eriophorum vaginatum . . . 2 . . . . 2 + II

Other species. Trees: Betula neoalaskana + in 3 and 9. Larix laricina 1 in 9. Characteristic species: Lycopodium annotinum 1 in 1 and 5. Betula exilis 3 in 2, 2 in 6. Orthilia secunda 1 in 3, 2 in 7. Betula occidentalis 1 in 1. Cornus canadensis 1 in 2. Pedicularis labradorica 1 in 3. Pyrola grandiflora 1 in 6. Petasites frigidus 1, Pyrola asarifolia 1, Cypripedium passerinum + in 8. Alnus sinuata 1, Salix monticola 1, Alnus fruticosa 1 in 9. Linnaea americana 1, Rhododendron lapponicum 1 in 10. Companion species: Peltigera scabrosa + in 5, 1 in 7. Calamagrostis inexpansa 1 in 1. Rumex arcticus 1 in 2. Equisetum pratense 1 in 3. Saxifraga hieracifolia 1 in 5. Carex vaginata 1, Eriophorum brachyantherum + in 8. Epilobium angustifolium +, Polygonum plumosum + in 9. Carex aquatilis +, Polemonium acutiflorum + in 10.

Localities: 1. Alaska: Taylor Hwy, 25 km N of Tetlin Junction. 63º31'N-142º25'W. 15 m, 30 cm, 200 m2 (reg. 1994a: 66). 2. Yukon Territory: Dawson City, Dempster Hwy, 90 km N from crossing. 64º52'N-138º21'W. 10 m, 25 cm, 200 m2 (reg. 1994a: 207). 3. Alaska: Robertson Lake. 63º34'N-143º53'W. 10 m, 20 cm, 100 m2 (reg. 1994a: 179). 4. Yukon Territory: Beaver Creek. 62º38'N-140º51'W. 15 m, 30 cm, 200 m2, gleyic peaty podzol (reg. 1994a: 169). 5. Alaska: Taylor Hwy, 5 km N from Tetlin Junction. 63º22'N-142º36'W. 10 m, 25 cm, gleyic peaty soil (reg. 1994a: 63). 6. Yukon Territory: Dawson City, Kloondike Hwy/Dempster Hwy crossing. 63º56'N-138º30'W. 6 m, 20 cm, 100 m2, gleyic peaty podzol (reg. 1994a: 79). 7. Yukon Territory: 20 km S of Stewart Crossing. 63º02'N-136º30'W. 20 m, 30 cm, 200 m2, peaty soil (reg. 1994a: 104). 8. Alaska: Gakona. 62º22'N-145º20'W. 18 m, 30 cm, 200 m2, gleyic peaty podzol (reg. 1994a: 58). 9. Alaska: Richardson. 64º17'N-146º26'W. 12 m, 25 cm, 100 m2, peaty soil (reg. 1994a: 189). 10. Yukon Territory: Pine Valley-Bear Flat. 61º36'N-139º24'W. 12 m, 20 cm, 100 m2 (reg. 1994a: 168). 11. Synthesized table.

Locality Alt.m Ic Io Tp Climactical forest association Bioclimate
Anchorage (Alaska) 26 24.8 4.6 598 Rubo-Piceetum marianae Bosc-Umbo-Lshu-Stp
Mc Grath (Alaska) 105 37.6 5.3 541 Rubo-Piceetum marianae Boco-Lsbo-Ushu
Talkeetna (Alaska) 109 27.2 8.9 578 Rubo-Piceetum marianae Bosc-Umbo-Lhum
Big Delta (Alaska) 386 36.1 4.0 572 Piceetum glauco-marianae Boco-Umbo-Lshu
Palmer (Alaska) 60 24.5 5.1 622 Piceetum glauco-marianae Bosc-Umbo-Ushu
Watson Lake (Yukon) 687 35.0 4.6 572 Piceetum glauco-marianae Boco-Umbo-Lshu
Fort Yukon (Alaska) 129 45.6 1.8 556 Hypno-Piceetum glaucae Boxe-Umbo-Sar-Stp
Fairbanks (Alaska) 133 39.3 3.2 573 Hypno-Piceetum glaucae Boxe-Umbo-Udry-Stp
Dawson (Yukon) 324 45.0 2.3 561 Hypno-Piceetum glaucae Boxe-Umbo-Udry-Stp
Whitehorse (Yukon) 828 32.3 2.8 553 Pulsatillo-Pinetum latifoliae Boxe-Umbo-Udry-Stp

Figure 16. Relationships between local climatic data, bioclimates and climactical and edaphophilous forest associations (climatic and edaphic climax) in the climactical territory (sigmion) of Ledo-Piceion marianae in Canada and Alaska (Yukonian-Alaskan Biogeographic Provinces).

Type relevé (holotypus): Peinado, Aguirre & Cruz 1998 in Plant Ecology 137: 183, tb. 15, relevé n. 394. 1998. Site: Alaska: Denali State Park. 62°53'53"N-149°44'07"W. 360 m, 200 m2. Estimated bioclimatic factors: Continental Boreal, subcontinental (Ic ~ 28), upper mesoboreal (Tp ~ 560), upper humid ( Io ~ 9.5), Positive Summer Temperature Tps ~ 390. Biogeographic location: North American Boreal Region, Yukonian-Alaskan Province, Continental Alaskan Sector, Boreal Subcontinental Alaskan Subsector. Floristic combination: Linnaeo-Piceetea characteristic species, trees: 3 Picea mariana. Others: 2 "Betula nana" [B. nana subsp. exilis], 1 Cornus canadensis, 1 Empetrum nigrum subsp. hermaphroditum, 1 Listera cordata, 1 Orthilia secunda, 1 Pentaphylloides floribunda, 1 Petasites frigidus var. nivalis, + Pyrola asarifolia subsp. asarifolia, 2 Rubus chamaemorus, 1 Rubus pedatus, 2 Salix arbusculoides, 2 Spiraea stevenii, 2 Vaccinium oxycoccos, 2 "Vaccinium uliginosum" [Vaccinium uliginosum subsp. minus], 1 "Vaccinium vitis-idaea" [Vaccinium vitis-idaea subsp. minus]. Companion species: 1 Carex pauciflora, 1 Drosera anglica, 2 "Equisetum arvense" [E. arvense var. boreale], 1 Salix fuscescens.

4b. Piceetum glauco-marianae Peinado, Aguirre & Cruz 1998

[Piceetum glauco-marianae Peinado, Aguirre & Cruz in Plant Ecology 137: 180. 1998, Calamagrostio purpurascentis-Piceetum marianae nobis ined.]

Continental Boreal (eucontinental and subcontinental); meso- and supraboreal; subhumid to humid; black spruce (Picea mariana) climactical coniferous mesoforests with some white spruces (Picea glauca var. glauca), growing on gleyic, dystric or gelic podzols as zonal climactical vegetation throughout the Yukonian-Alaskan Province territories.

Bioclimatic diagnosis: Ic 22-46, Io 3.6-10.0, Tp 380-640, Tps 300-420, Tmin < -10, m < -15. [Bosc, Boco-Mbo, Sbo-Shu, Hum].

Table 11 gives five relevés of Piceetum glauco-marianae sampled in Alaska, which represent the climactical vegetation-type (zonal climax), throughout the meso- and supraboreal eucontinental and subcontinental subhumid and humid territories of the Continental Alaskan Sector. In the same ecological conditions, on dystric or gleyic podzol soils, this mesoforest communities spreading also into Cassiar and Mackenzie Mountains Sector areas. Floristically, is similar to Rubo-Piceetum marianae association growing on boggy soils but in Piceetum glauco-marianae associationare absent Carex lugens, Vaccinium oxycoccos and the rest of characteristic species of Oxycocco-Sphagnetea vegetation class. Among the grasses, Calamagrostis purpurascens seems to be uncommon in Rubo-Piceetum, but is a common plant in Piceetum glauco-marianae association; for that reason we thinked to propose the name Calamagrostio-Piceetum marianae nobis ined. for this association, before the Peinado & al. (1998) publication. The secondary deciduous woodlands growing after fires or destruction of these coniferous forests are dominated by Alaska birch (Betula neoalaskana) or quacking aspen (Populus tremuloides) and belong to Piceo-Betuletum neoalaskanae association (Betulo neoalaskanae-Populion tremuloidis, Betulo papyriferae-Populetalia tremuloidis).

Table 11
4b. Piceetum glauco-marianae

(Ledo-Piceion marianae, Gaultherio-Piceetalia)

Altitude (1=10 m) 60 49 9 58 57 47
Number of species 19 19 20 22 23 21
Ordinal number 1 2 3 4 5 6
Trees:
Picea mariana 5 4 5 5 5 V
Picea glauca 1 2 . 1 + IV
Characteristic species:
Ledum groenlandicum 3 4 3 4 3 V
Vaccinium minus 3 4 2 3 5 V
Linnaea americana 3 1 1 1 + V
Cornus canadensis 2 1 1 1 2 V
Calamagrostis purpurascens 1 3 1 1 2 V
Rubus chamaemorus 1 2 2 1 + V
Salix acutifolia 1 2 . 1 1 IV
Geocaulon lividum 1 . 1 1 3 IV
Vaccinium alpinum . 2 3 2 2 IV
Equisetum sylvaticum . 1 3 3 + IV
Alnus fruticosa . 1 + 1 + IV
Petasites nivalis + 2 . 2 . III
Rosa sayi 2 . + 1 . III
Spiraea stevenii . 1 1 1 . III
Polygonum alaskanum . 1 . 1 1 III
Mertensia paniculata 1 + . . . II
Salix arbusculoides 1 . 1 . . II
Betula glandulosa . 1 1 . . II
Arctagrostis arundinacea . 1 . 2 . II
Lycopodium annotinum . . 1 . 1 II
Companion species:
Bryophyta gen.et sp. pl. 5 5 5 5 5 V
Peltigera canina 2 . 1 1 1 IV
Peltigera aphtosa . . 2 . 2 II
Cladina mitis . . . 2 1 II

Other species. Trees: Picea glauca x mariana 1 in 5. Characteristic species: Empetrum hermaphroditum + in 1. Betula occidentalis 1 in 3. Pedicularis labradorica 1 in 4. Salix bebbiana 1, Cornus suecica 2 in 5. Companion species: Equisetum pratense 1, Stellaria longipes + in 1. Epilobium angustifolium + in 5.

Localities: 1. Alaska: Tok between Cathedral Rapids and Robertson River. 63º25'N-143º50'W. E, 10%, 15 m, 30 cm, 400 m2, gleyic podzol (reg. 1994a: 171). 2. Alaska: Richardson, Tanana Valley State Forest. 64º18'N-146º21'W. N, 30%, 18 m, 40 cm, 400 m2 (reg. 1994a: 191). 3. Alaska: Kashwitna, Willow Creek. 61º48'N-150º10'W. W, 20%, 15 m, 30 cm, 200 m2, gleyic podzol (reg. 1994a: 208). 4. Alaska: Dot Lake. 63º35'N-143º55'W. W, 15%, 18 m, 40 cm, 400 m2 (reg. 1994a: 185). 5. Alaska: Fairbanks, Alder Creek. 64º45'N-148º05'W. S, 20%, 20 m, 40 cm, 400 m2 (reg. 1994a: 195). 6. Synthesized table.

Type relevé (holotypus): Peinado, Aguirre & Cruz 1998 in Plant Ecology 137: 180, tb. 14, relevé n. 301. 1998. Site: British Columbia, 30 km south of Upper Liard. 59°49'30"N-129°07'56"W. 600 m, 200 m2. Estimated bioclimatic factors: Continental Boreal, eucontinental (Ic ~ 36), upper mesoboreal (Tp ~ 530), upper subhumid (Io ~ 5.0), Positive Summer Temperature Tps ~ 380. Biogeographic location: North American Boreal Region, Yukonian-Alaskan Province, Cassiar and Mackenzie Mountains Sector, Cassiar Mountains Subsector. Floristic combination: Linnaeo-Piceetea characteristic species, trees: 1 Picea glauca var. glauca, 4 Picea mariana. Others: 1 Arctostaphylos rubra, 1 Geocaulon lividum, 1 Ledum groenlandicum, 1 Linnaea borealis subsp. longiflora [L. americana], 1 Moneses uniflora, 1 Salix glauca [S. glauca var. glauca], + Vaccinium vitis-idaea. Companion species: 1 Leymus aff. cinereus.