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: Hypno procerrimi-Piceetum glaucae

4c. Hypno procerrimi-Piceetum glaucae Hoefs, Cowan & Krajina ex Peinado, Aguirre & Cruz 1998

[Hypno procerrimi-Piceetum glaucae Hoefs, Cowan & Krajina ex Peinado, Aguirre & Cruz in Plant Ecology 137: 167. 1998, Hypno-Abietinello-Piceetum glaucae Hoefs, Cowan & Krajina (art. 10), Betulo nanae-Piceetum glaucae Peinado, Alcaraz, Aguirre, & Martínez-Parras ex Peinado, Aguirre & Cruz in Plant Ecology 137: 176. 1998 (art. 25), Mertensio paniculatae-Piceetum glaucae nobis ined.]

Xeric and Continental Boreal; meso-, supraboreal; semiarid to lower subhumid; mostly steppic; white spruce (Picea glauca var. glauca) open mesoforests, growing as climactical Xeric Boreal zonal vegetation or as permanent edapho-psammophilous forest communities on haplic, dystric, gleyic or gelic podzols and evolved regosols throughout the Continental Boreal lower subhumid areas, in the Cassiar and Mackenzie Mountains Sector (Cassiar Mountains and Great Bear Lake Subsectors), and the Continental Alaskan Sector (Boreal Xeric Alaskan Subsector) and locally in sandy deep soils in the eastern district of Boreal Subcontinental Alaskan Subsector territories.

Map Figure 17. Distribution of the forest plant communities belonging to alliance 4. Ledo decumbentis-Piceion marianae (Yukonian-Alaskan Province): 4a. Rubo chamaemori-Piceetum marianae (Yukonian-Alaskan Province, locally in Northern Rocky Mountain Province and Columbia Mountains Sector, thermo-, meso-, supraboreal and hemiboreal dry to humid, boggy soils), 4b. Piceetum glauco-marianae (Yukonian-Alaskan Province, meso- and supraboreal, Dry to Humid, on podzols), 4c. Hypno procerrimi-Piceetum glaucae (Yukonian-Alaskan Province, meso- and supraboreal, dry to subhumid, steppic, on regosols), 4d. Pulsatillo multifidae-Pinetum latifoliae (Cassiar Mountain Subsector, meso- and supraboreal dry, steppic, on regosols).

Bioclimatic diagnosis: Ic 28-46, Io 1.8-4.5, Tp 380-600, Tps 300-450, Tmin < -15º, m < -19º. [Boco-mbo, Sbo-Usar, Ldry-Stp].

Table 12 shows thirteen relevés from Alaska and Yukon Territory, mostly sampled throughout the Xeric meso- and supraboreal, steppic continental areas of the Cassiar Mountains and Boreal Xeric Alaskan Subsectors. Those of the eastern district of Boreal Eucontinental Alaskan Subsector, such as relevés 1, 6 and 9, belong to exceptionally dry areas of rainshadow valleys or dry stations with deep sandy soils or south exposed slopes (permanent edapho-xerophilous forest communities). The type relevé of the association is supraboreal and includes Juniperus communis var. depressa, and probably corresponds to a windy locality of Sheep Mountains (Yukon Territory).

In higher altitudes, cold and wet stations (relevés 10 to 13), could be recognized a variant with Betula glandulosa and Salix glauca var. acutifolia. The lower mesoboreal localities, probably belong to the most general boreal xeric variant. Shepherdia canadensis, also common in Pulsatillo-Pinetum latifoliae, seems to be a good differential species to contrast Rubo-Piceetum marianae and Piceetum glauco-marianae associations. The name Mertensio paniculatae-Piceetum glaucae was chosen by us before knowing the name recently published by Peinado, Aguirre & Cruz (1998).

Table 12
4c. Hypno procerrimi-Piceetum glaucae

(Ledo-Piceion marianae, Gaultherio-Piceetalia)

Altitude (1=10 m) 82 50 35 90 60 46 70 50 50 78 93 102 61 67
Number of species 16 16 16 17 17 18 19 20 21 23 25 26 26 20
Ordinal number 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Trees:
Picea glauca 5 5 5 4 5 5 5 5 4 5 5 5 4 V
Populus tremuloides + + 1 + . . + . . 1 . . + IV
Betula neoalaskana . . + . . + + + . . . . + III
Characteristic species:
Mertensia paniculata + 1 1 1 2 3 2 2 1 1 3 2 1 V
Vaccinium minus 1 + 1 3 + 1 3 1 2 . . 3 3 V
Rosa sayi 1 + + . + 3 2 2 2 . + 3 1 V
Shepherdia canadensis + + . 2 + + 1 2 1 + . . + V
Linnaea americana . 1 2 . 2 2 1 . 1 4 . 2 + IV
Geocaulon lividum 3 1 2 3 . . 3 3 2 4 . . . IV
Lupinus arcticus 2 1 . . . . 1 . + 3 3 2 2 IV
Empetrum hermaphroditum 1 . . . + . . 2 2 2 2 2 2 IV
Orthilia secunda . . 1 . 2 1 1 . 2 1 . + . IV
Calamagrostis purpurascens . 2 + 3 . 2 2 . . . . . 1 III
Ledum groelandicum 2 .   . . + . 2 3 . . + . III
Salix acutifolia . . . 1 . . . . . 3 2 2 1 III
Arctostaphylos rubra . . . . . . . . 3 1 2 + 2 III
Arctagrostis arundinacea 1 . . . . . . 2 . . . 2 + II
Viburnum edule . + + . . + + . . . . . . II
Pyrola asarifolia . . . . . 1 . . 1 3 . 1 . II
Cornus canadensis . . . . . 3 . . 2 1 . . 2 II
Betula glandulosa . . . . . . . . . 2 2 1 4 II
Alnus fruticosa + . 1 . . . . + . . . . . II
Gentianella propinqua . + . . + . + . . . . . . II
Hedysarum americanum . . . . 1 . . 1 3 . . . . II
Pentaphylloides floribunda . . . . . . . . 1 . 1 . 1 II
Pulsatilla multifida 2 . . 1 . . . . . . . . . II
Zigadenus elegans . . . . + . . . . 1 . . . II
Companion species:
Bryophyta gen. et sp. pl. 5 4 5 4 5 3 4 5 2 2 4 3 3 V
Epilobium angustifolium . 2 + + + 1 + . 1 1 1 2 1 V
Cladina mitis 2 . 2 5 1 . 2 . . . . 1 2 IV
Peltigera canina 2 . . . 2 . 2 2 . . . . . II
Festuca altaica . . . . 1 . . . . 1 2 . 2 II
Galium boreale . . . + . 2 . . . . . . 1 II

Other species. Trees: Populus balsamifera + in 3, 1 in 11. Characteristic species: Solidago nana + in 2 and 4. Arctostaphylos uva-ursi 2 in 4, + in 7. Penstemon procerus + in 5, 1 in 10. Petasites frigidus 1 in 8, 2 in 9. Equisetum scirpoides 4 in 8, 2 in 9. Ribes triste 1 in 8, 2 in 12. Vaccinium alpinum 1 in 8, 3 in 13. Petasites nivalis 1 in 12 and 13. Betula occidentalis + in 12 and 13. Arnica angustifolia + in 2. Polemonium pulcherrimum + in 4. Trientalis arctica 1 in 6. Boschniakia rossica 1, Goodyera repens 1 in 8. Pyrola minor 1 in 9. Arctostaphylos adenotricha 3, Arnica latifolia 2, Antennaria rosea +, Pedicularis labradorica + in 10. Solidago multiradiata 2, Luzula parviflora 1, Polemonium acutiflorum 1, Rubus arcticus 1, Artemisia tilesii +, Salix planifolia +, Saussurea angustifolia 1 in 11. Lycopodium annotinum 2, Senecio lugens +, Calamagrostis langsdorfii +, Delphinium glaucum + in 12. Companion species: Equisetum pratense 4 in 6, 3 in 12, + in 13. Saxifraga tricuspidata 1 in 4. Delphinium brachycentrum 2, Carex scirpoidea 1, Salix reticulata 1, Ptilium crista-castrensis 2, Valeriana capitata + in 11. Salix hastata 1 in 12.

Localities: 1. Alaska: Tok, Tetlin Junction. 63º20'N-142º52'W. SW, 20%, 20 m, 200 m2, podzol on paleodunes (reg. 1994a: 61). 2. Yukon Territory: Minto. 62º34'N-136º51'W. W, 10%, 14 m, 20 cm. 260 m2, podzol on sandy sediments (reg. 1994a: 108). 3. Alaska: Fairbanks, Bonanza Creek. 64º46'N-148º13'W. S, 15%, 30 m, 40 cm, 500 m2, till sediments (reg. 1994a: 197). 4. Yukon Territory: 20 km N of Stewart Crossing. 63º32'N-137º09'W. S, 5%, 25 m, 50 cm, 500 m2 (reg. 1994a: 103). 5. Yukon Territory: Champagne, 3 km W of Mendelhall. 60º53'N-136º45'W. S, 5%, 27 m, 30 cm, 250 m2 (reg. 1994a: 122). 6. Alaska: Delta Junction, Delta, Quartz Lake. 64º13'N-145º13'W. 30 m, 50 cm, 400 m2, iron podzol (reg. 1994a: 188). 7. Yukon Territory.: 12 km N of Pelly Crossing. 62º55'N-136º35'W. W, 20%, 25 m, 40 cm, 400 m2, iron podzol (reg. 1994a: 107). 8. Alaska: Gakona. 62º20'N-145º20'W. NW, 10%, 25 m, 40 cm, 400 m2 (reg. 1994a: 57). 9. Alaska: Tonsina. 61º38'N-144º43'W. 20 m, 40 cm, 400 m2 (reg. 1994a: 53). 10. Yukon Territory: Haines Junction, Quill Creek. 60º48'N-137º49'W. E, 10%, 25 m, 50 cm, 400 m2 (reg. 1994a: 124). 11. Alaska: Mckinley Park, Denali National Park. 63º43'N-149º11'W. 25 m, 80 cm, 400 m2 (reg. 1994a: 203). 12. Yukon Territory: Dawson City, Dempster Hwy 80 km N from crossing. 64º41'N-138º27'W. 30 m, 50 cm, 400 m2, gleyic podzol (reg. 1994a: 84). 13. Alaska: Healy. 63º49'N-149º03'W. W, 10%, 14 m, 30 cm, 260 m2 (reg. 1994a: 198). 14. Synthesized table.

Type relevé (lectotypus): Hoefs, Cowan & Krajina 1976, tb. 15, relevé n. 10 (selected by Peinado, Aguirre & Cruz in Plant Ecology 137: 167. 1998). Site: Yukon Territory. Sheep Mountain, stabilized aeolian deposits (loess), 1160 m, 18%. Estimated bioclimatic factors: Continental Boreal, eucontinental (Ic ~ 32), lower supraboreal (Tp ~ 480), upper dry (Io ~ 3.4), Positive Summer Temperature Tps ~ 350. Biogeographic location: North American Boreal Region, Mackenzie-Yukonian Province, Cassiar and Mackenzie Mountains Sector, Cassiar Mountains subsector. Floristic combination: Linnaeo-Piceetea characteristic species, trees: 7.6 [4] Picea glauca, 3.3 [2] Picea glauca (S2). Others: 1.+ [1] Anemone multifida, 3.4 [2] Arctostaphylos rubra, 2.4 [1] Arctostaphylos uva-ursi, 1.1 [1] Equisetum scirpoides, 1.+ [1] Gentiana propinqua [Gentianella propinqua], 2.4 [1] Geocaulon lividum, 3.4 [2] "Juniperus communis" [Juniperus communis var. depressa], 4.4 [3] Linnaea borealis [L. americana], 2.1[2] Pyrola secunda [Orthilia secunda], +.+ [+] "Rosa acicularis" [R. acicularis subsp. sayi], 3.4 [2] Salix glauca [S. glauca var. glauca], 2.3 [1] Shepherdia canadensis. Companion species: 2.4 [2] Abietinella abietina, +.+ [+] Carex concinna, 2.2 [2] Cladonia pocillum, 1.2 [1] Distichium capillaceum, 3.5 [2] Hypnum procerrimum, 2.2 [1] Peltigera canina, +.1 [+] Stereocaulon glareosum, +.1 [+] Stereocaulon rivulorum, +.1 [+] Tomentypnum nitens. [Between brackets the Braun-Blanquet estimated indexes].

Associations Biogeography Ombrotypes Thermotypes
(Ledo-Piceion marianae) 2aa 2ab 2ac 2ba 2bb 2bc Sar Dry Shu Hum Tbo Mbo Sbo St
4a. Rubo-Piceetum marianae + + + + + + + + + + + + + +
4b. Piceetum glauco-marianae + + + + + + . . + + . + + .
4c. Hypno-Piceetum glaucae + . + . + + + + + . . + + +
4d. Pulsatillo-Pinetum latifoliae + . . . . . . + . . . + + +

Figure 18. Relationships between biogeographic subsectors and bioclimatic belts (ombrotypes and thermotypes) and the associations of Ledo-Piceion marianae alliance (Yukonian-Alaskan Province). Biogeography: 2.2. Yukonian-Alaskan Province: 2.2a. Cassiar and Mackenzie Mountains Sector, Subsectors: 2aa. Cassiar Mountains, 2ab. Mackenzie Mountains, 2ac. Great Bear Lake; 2.2b. Continental Alaska Sector, Subsectors: 2ba. Boreal Subcontinental Alaskan, 2bb. Boreal Eucontinental Alaskan, 2bc. Boreal Xeric Alaskan. Bioclimatology: Sar: Semiarid, Shu: Subhumid, Hum: Humid. Thermotypes: Tbo: Thermoboreal, Mbo: Mesoboreal, Sbo: Supraboreal. Bioclimatic variants: Stp: Steppic.

4d. Pulsatillo multifidae-Pinetum latifoliae Lausi & Nimis in Peinado, Aguirre & Cruz 1998 corr. hoc loco

[Pinus contorta-Hylocomium splendens community and Pinus contorta-lichen woodland community Lausi & Nimis in Nimis & Crovello, Quant. Appr. Phytog.: 65, tb. 7, relevés 1-40. 1991, Pulsatillo patentis-Pinetum latifoliae Peinado, Aguirre & Cruz 1998 in Plant Ecology 137: 170. tb. 7, 10 relevés (which 7 from Lausi & Nimis, loc. cit.). 1998, Shepherdio-Pinetum latifoliae nobis ined.]

Xeric and Continental Boreal (continental, eucontinental); meso- and supraboreal and steppic dry; interior lodgepole pine (Pinus contorta var. latifolia) forests growing on regosols or haplic podzols, as pyrogenic or permanent edapho-psammophilous forest communities on sand deposits. Their distribution covers the territories of the Cassiar Mountains Subsector (Cassiar and Mackenzie Sector, Yukonian-Alaskan Province). The interior lodgepole pine (Pinus contorta var. latifolia) has its northern boundary distribution in Yukon Territory (Canada), not far away north of Whitehorse.

Bioclimatic diagnosis: Ic 28-38, Io 2.0-3.6, Tp 400-600, Tps 300-450, Tmin < -15º, m < -19º. [Boco-mbo, Sbo-Dry-Stp].

Table 13 shows two relevés from a Pinus contorta var. latifolia pyrogenic old forest. Interior lodgepole pine is the dominant tree in these forests and in the undercanopy are common young trees such as Picea glauca var. glauca and Populus tremuloides. Juniperus communis var. depressa, Shepherdia canadensis, Arctostaphylos uva-ursi (incl. var. adenotricha), Salix glauca var. acutifolia, Rosa acicularis subsp. sayi and Empetrum nigrum subsp. hermaphroditum are the most common shrubs and dwarf-shrubs in the understory growing with Calamagrostis purpurascens and Festuca altaica as habitual perennial grasses. Our non-published original name for this association was Shepherdio canadensis-Pinetum latifoliae nobis ined.

Type relevé (holotypus): Peinado, Aguirre & Cruz 1998 in Plant Ecology 137: 170, tb. 7, n. 442. Site: Yukon Territory. Between Mayo and Stewart. 63°31'N-136°11'W. 540 m, 200 m2. Estimated bioclimatic factors: Xeric Boreal, continental (Ic ~ 32), upper mesoboreal, steppic (Tp ~ 550), upper dry (Io ~ 3.0), 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: 2 Picea glauca var. glauca, 2 Picea mariana, 3 Pinus contorta var. latifolia. Others: 1 Aconitum delphiniifolium [A. delphiniifolium subsp. delphiniifolium], 1 Arctostaphylos uva-ursi, + Calamagrostis rubescens, 1 Cornus canadensis, + Ledum groenlandicum, 1 Linnaea borealis subsp. longiflora [L. americana], + Lupinus arcticus subsp. arcticus, + Mertensia paniculata var. paniculata, 1 Pulsatilla patens [P. patens subsp. multifida], 1 Rosa acicularis subsp. sayi. Companion species: 1 Zigadenus elegans.

Remarks: The correction of association name Pulsatillo patentis-Pinetum latifoliae into Pulsatillo multifidae-Pinetum latifoliae is obliged (art. 43) because Pulsatilla patens sensu Peinado, Aguirre & Cruz, non (L.) P. Mill. belongs to Pulsatilla patens subsp. multifida (Pritz.) Zamels.

 Table 13
4d. Pulsatillo multifidae-Pinetum latifoliae

(Ledo-Piceion marianae, Gaultherio-Piceetalia)

Altitude (1=10 m) 70 77 73
Number of species 20 21 20
Ordinal number 1 2 3
Trees:
Pinus latifolia 5 5 2
Picea glauca (S2) 1 1 2
Populus tremuloides (S2) 2 . 1
Characteristic species:
Calamagrostis purpurascens 3 1 2
Shepherdia canadensis 2 3 2
Rosa sayi 2 2 2
Arctostaphylos adenotricha 1 3 2
Linnaea americana 1 2 2
Salix acutifolia 1 2 2
Cornus canadensis 1 + 2
Pulsatilla multifida 1 + 2
Pyrola chlorantha + 1 2
Vaccinium minus + 1 2
Juniperus depressa + + 2
Lupinus arcticus + + 2
Companion species:
Cladina mitis 2 4 2
Epilobium angustifolium + + 2

Other species. Characteristic species: Arctostaphylos uva-ursi 3, Galium boreale 1, Geocaulon lividum 1 in 1. Ledum groenlandicum 2, Zigadenus elegans 1, Empetrum hermaphroditum 1, Orthilia secunda + in 2. Companion species: Festuca altaica 2 in 2.

Localities: 1. Yukon Territory: Whitehorse. 60º37'N-134º57'W. NW, 10%, 14 m, 25 cm, 400 m2, podzol on sandy sediments (reg. 1994a: 115). 2. Yukon Territory: Whitehorse, McIntyre Creek. 60º38'N-134º45'W. S, 15%, 12 m, 20 cm, 400 m2, podzol on sand deposits, (reg. 1994a: 119). 3. Synthesized table.