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TABLE 4. Climatic characteristics for the biogeoclimatic zones of British Columbia

ZoneRange and

Lat. Long. ElevationMean annual Mean summer Mean precip. Mean precip.

Driest Wettestreference( ° ′ ) ( ° ′ ) (m)

precip.precip. of driest of wettest

month monthstation (mm)(May-Sept) month month

(mm) (mm) (mm)

AT Old Glory Mtn. 49 09 117 55 2347 755.5 287.0 40.0 84.1 Jul Dec

BG Max 588 335.7 174.5 17.3 55.4Min 297 205.6 98.0 8.0 27.3Kamloops 50 40 120 20 379 241.7 111.4 8.0 36.1 Mar Jan

BWBS Max 840 503.7 305.3 24.3 879.0Min 382 327.1 144.7 8.3 41.1Fort Nelson A 58 50 122 35 382 451.8 297.9 16.7 84.3 Apr Jul

CDF Max 223 1262.6 238.3 38.6 232.9Min 8 647.2 107.3 13.4 119.2Victoria Int’l A 48 39 123 26 19 872.9 141.9 18.1 157.3 Jul Dec

CWH Max 671 4386.8 1162.0 151.0 625.4Min 0 990.2 159.3 16.8 145.7Haney UBC 49 16 122 34 143 2140.1 467.8 65.5 331.7 Jul Dec

RF Admin

ESSF Max 1862 1995.4 424.5 64.8 297.4Min 863 514.1 204.6 26.6 57.4Boss Mountain 52 06 120 53 1532 1177.1 401.6 63.5 140.6 May Dec

ICH Max 1085 1419.0 439.3 57.2 224.3Min 314 497.7 199.9 21.4 57.8Revelstoke 51 00 118 12 456 1063.7 325.0 51.4 177.0 Apr Jan

IDF Max 1128 1198.9 290.7 37.6 208.8Min 122 295.1 107.5 13.5 34.8150 Mile House 52 07 121 56 738 414.2 214.0 15.8 60.7 Apr Jun

MH Hollyburn Ridge 49 23 123 12 930 2954.3 694.4 106.9 434.8 Jul Dec

MS Max 1554 663.8 252.1 38.5 108.1Min 1128 380.8 158.2 17.9 45.2Peachland 49 52 120 00 1520 638.3 197.0 29.3 89.1 Apr Dec

Brenda Mines

PP Max 939 604.5 270.3 30.7 77.6Min 244 319.5 86.3 11.0 34.5Kelowna 49 54 119 28 354 332.2 136.3 15.3 45.1 Apr Dec

SBPS Max 1219 517.8 299.8 21.1 86.5Min 914 464.1 242.6 20.8 36.4Alexis Creek 52 33 123 11 1219 464.1 242.6 20.8 57.6 Apr Jun

Tautri Creek

SBS Max 1245 1588.2 352.6 36.8 278.7Min 488 438.9 188.9 15.2 49.8Prince George A 53 63 122 40 676 628.3 300.8 27.4 68.2 Apr Aug

SWB Cassiar 59 17 129 50 1078 699.5 275.1 25.7 84.2 Apr Oct

Zone key

AT Alpine TundraBG BunchgrassBWBS Boreal White and Black SpruceCDF Coastal Douglas-firCWH Coastal Western HemlockESSF Engelmann Spruce — Subalpine FirICH Interior Cedar — Hemlock

IDF Interior Douglas-firMH Mountain HemlockMS Montane SprucePP Ponderosa PineSBPS Sub-Boreal Pine — SpruceSBS Sub-Boreal SpruceSWB Spruce — Willow — Birch

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TABLE 5. Occurrencea of trees in the biogeoclimatic zones of British Columbia

Gymnosperms BG PP IDF ICH MS SBPS SBS BWBS SWB MH CDF CWH ESSF ATb

Abies amabilis - - - + - - - - - +++ - +++ (+) -(amabilis fir)

A. grandis- - ++ ++ + - - - - - ++ + - -(grand fir)

A. lasiocarpa- - - ++ +++ (+) +++ ++ +++ ++ - + +++ -(subalpine fir)

Chamaecyparisnootkatensis - - - - - - - - - +++ - ++ (+) -

(yellow-cedar)

Juniperus scopulorum+ + ++ - - - + (+) - - ++ (+) - -(Rocky Mountain juniper)

Larix laricina- - - - - - (+) ++ - - - - - -(tamarack)

L. lyallii- - - - - - - - - - - - ++ -(alpine larch)

L. occidentalis- + +++ ++ +++ - - - - - - - + -(western larch)

Picea engelmannii- - + ++ +++ - - - - + - - +++ -(Engelmann spruce)

P. engelmanniix glauca - (+) ++ ++ +++ + +++ - - - - - ++ -

(hybrid white spruce)

P. glauca- (+) + - + +++ ++ +++ +++ - - - + -(white spruce)

P. glaucax sitchensis - - - ++ - - - - - (+) - ++ - -

(Roche spruce)

P. mariana- - - + - - ++ +++ + - - - - -(black spruce)

P. sitchensis- - - - - - - - - + + +++ - -(Sitka spruce)

Pinus albicaulis- - - - - - - - - + - - ++ -(whitebark pine)

P. banksiana- - - - - - - (+) - - - - - -(jack pine)

P. contorta(+) - +++ ++ +++ +++ +++ +++ ++ + ++ ++ +++ -(lodgepole pine)

P. flexilis- - (+) - - - - - - - - - (+) -(limber pine)

P. monticola- - + ++ + - - - - + + ++ + -(western white pine)

P. ponderosa+ +++ +++ + - - - - - - - - - -(ponderosa pine)

Pseudotsuga menziesii+ ++ +++ ++ +++ + ++ - - (+) +++ +++ + -(Douglas-fir)

Taxus brevifolia- - + ++ - - - - - - ++ ++ - -(western yew)

Thuja plicata- (+) ++ +++ + - + - - + ++ +++ + -(western redcedar)

Tsuga heterophylla- - + +++ + - (+) - - ++ + +++ + -(western hemlock)

T. mertensiana- - - + - - - - - +++ - + ++ -(mountain hemlock)

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TABLE 5. Continued

Angiosperms BG PP IDF ICH MS SBPS SBS BWBS SWB MH CDF CWH ESSF ATb

Acer macrophyllum- - + - - - - - - - ++ ++ - -(bigleaf maple)

Alnus rubra- - - - - - - - - - +++ +++ - -(red alder)

Arbutus menziesii- - - - - - - - - - ++ + - -(arbutus)

Betula neoalaskana- - - - - - - ++ - - - - - -(Alaska paper birch)

B. occidentalis+ + + (+) - - (+) + - - - - - -(water birch)

B. papyrifera+ + ++ ++ + - ++ ++ - - + + - -(paper birch)

Cornus nuttallii- - + - - - - - - - ++ ++ - -

(western floweringdogwood)

Populus balsamiferassp. balsamifera - - - - - - + ++ + - - - - -

(balsam poplar)

P. balsamiferassp. trichocarpa + + + ++ + + ++ + - - ++ ++ + -

(black cottonwood)

P. tremuloides+ ++ +++ ++ ++ + +++ +++ + - + + +(trembling aspen)

Prunus emarginata- - +c ++c - - +c - - - ++ + - -(bitter cherry)

Quercus garryana- - - - - - - - - - ++ (+) - -

(Garry oak)

Rhamnus purshiana- - - ++d - - - - - - ++ + - -(cascara)

a Occurrence classes: +++(abundant); ++(common); +(present but uncommon); (+)(very rare); -(absent).b Tree species occur only in krummholz form in the Alpine Tundra zone.c P. emarginata occurs in these zones, but only rarely as a (small) tree.d Rarely as a small tree.

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Chapter 6: Coastal Western Hemlock Zone

by

J. Pojar, K. Klinka, and D.A. Demarchi

LOCATION AND DISTRIBUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

ECOLOGICAL CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

NOTES ON CLASSIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

SUBZONES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

SOME REPRESENTATIVE SITE ASSOCIATIONS . . . . . . . . . . . . . . . . . . . . . . . . 100

Western hemlock — Flat moss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Douglas-fir — Western hemlock — Salal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Redcedar — Lady fern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Redcedar — Sitka spruce — Skunk cabbage . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

WILDLIFE HABITATS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

RESOURCE VALUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

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LOCATION AND DISTRIBUTION

The Coastal Western Hemlock zone (CWH) occurs at low to middle elevationsmostly west of the coastal mountains, along the entire British Columbia coast(Figure 18) and on into both Alaska and Washington/Oregon. The zone covers muchof Vancouver Island, the Queen Charlotte Islands, and the Coast Mountains. Itpenetrates the coastal mountain barrier somewhat in major river valleys, especiallyalong the Fraser and Skeena rivers. The CWH occupies elevations from sea level to900 m on windward slopes in the south and mid-coast (1050 m on leeward slopes),and to 300 m in the north. The Mountain Hemlock zone is usually the subalpinezone above the CWH.

ECOLOGICAL CONDITIONS

The CWH is, on average, the rainiest biogeoclimatic zone in British Columbia(Table 4). The zone typically has a cool mesothermal climate: cool summers (althoughhot dry spells can be frequent) and, like the Coastal Douglas-fir zone (CDF), mildwinters (Figure 19). Mean annual temperature is about 8°C and ranges from 5.2 to10.5°C among the CWH subzones. The mean monthly temperature is above 10°C for4-6 months of the year. The mean temperature of the coldest month is 0.2°C andranges from -6.6 to 4.7°C among the subzones. Mean annual precipitation for thezone as a whole is 2228 mm, and ranges from 1000 to 4400 mm (and probably morein some areas). Less than 15% of total precipitation occurs as snowfall in the south,but as much as 40-50% in the northern parts of the zone.

Western hemlock is usually the most common species in the forest cover. Itregenerates freely under the canopy of mature stands on zonal sites and elsewhere ifsufficient acid raw humus or decaying wood has accumulated on the forest floor.Western redcedar occurs frequently throughout the zone south of 56°N latitude.Douglas-fir is widespread south from Dean Channel or roughly 53° (the speciesreaches its northern limit along the coast at Kemano), but is most abundant in drierparts of the zone. Amabilis fir and yellow-cedar are common only in wetter parts ofthe zone. Amabilis fir often dominates forests at upper elevations or more northerlylatitudes of the zone, but does not range north much beyond the Nass River, and isabsent from the Queen Charlotte Islands. Shore (lodgepole) pine is common on verydry or very wet (boggy) sites throughout the zone. Grand fir, western white pine, andbigleaf maple occur in warmer and drier, southern parts of the zone. Red alder is awidespread species on logged-over or otherwise disturbed sites; black cottonwoodusually occurs only along large rivers with extensive floodplains. Sitka spruce is alsoa widespread species, but is largely restricted in the south to specialized habitatssuch as floodplains and exposed beaches. However, north of Vancouver Island it gainsin importance, occurring over a wide variety of habitats and even forming a minorcomponent of climatic climax ecosystems on the Queen Charlotte Islands and on thenorthern mainland.

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FIGURE 18. Coastal Western Hemlock zone.

FIGURE 19. Representative climatic diagram for the Coastal Western Hemlock zone.

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Characteristic floristic features of zonal ecosystems in the CWH are: (a) theprominence of western hemlock; (b) the sparse herb layer; (c) the predominance ofseveral moss species (especially Hylocomium splendens [step moss] andRhytidiadelphus loreus [lanky moss]).

Zonal hypermaritime forests are dominated by mixtures of western hemlock,western redcedar, Sitka spruce, and variable amounts of yellow-cedar. Amabilis fir isonly locally abundant. Yellow-cedar, shore pine, and mountain hemlock increase inabundance in scrubby forests of the outer coast. Highly productive stands of westernhemlock — Sitka spruce or western hemlock — amabilis fir occur on well-drained soils,often on steep slopes. Well-drained fluvial sites support excellent stands of Sitka spruce,western hemlock, western redcedar, red alder, and sometimes amabilis fir. Bogs arestrikingly abundant over much of the hypermaritime landscape, especially on thecoastal lowlands (e.g., Hecate Lowland, Nahwitti Lowland, Queen Charlotte Lowland).The extensive peatlands form a mosaic of blanket bog, bog woodland, and scrub foreston the subdued terrain.

Western hemlock, amabilis fir, western redcedar, Sitka spruce, and (especially withincreasing elevation) yellow-cedar dominate the forests of the wetter maritimesubzones, which cover the majority of the zone as a whole. Western hemlock andamabilis fir dominate the canopy of late seral stands. Windthrow plays an importantrole in the persistence of these species; relatively young and more or less even-agedstands are common as a result. Western redcedar stands typically occupy steep slopesor sites that regenerated following fire and/or have not been disturbed by windthrow forseveral centuries. Typical zonal stands are characterized by the Western hemlock —Amabilis fir — Alaskan blueberry association. This vegetation type features a well-

developed shrub layer of ericaceous species (Vaccinium alaskaense [Alaskan blueberry],V. parvifolium [red huckleberry], Gaultheria shallon [salal]) and advance regenerationof western hemlock and amabilis fir, a poorly developed herb layer typified byBlechnum spicant (deer fern), and a well-developed moss layer dominated byRhytidiadelphus loreus, Hylocomium splendens, and Kindbergia oregana (Oregonbeaked moss).

Drier maritime forests typically have a substantial component of Douglas-fir alongwith western hemlock and western redcedar. Gaultheria shallon, Mahonia nervosa (dullOregon-grape), and Vaccinium parvifolium typify the poorly to moderately developedshrub layer. Kindbergia oregana, Hylocomium splendens, Rhytidiadelphus loreus, andPlagiothecium undulatum (flat moss) dominate the well-developed moss layer.

Submaritime forests are characterized by the scarcity of typically coastal speciessuch as Gaultheria shallon and yellow-cedar, and the presence of typically interior orcontinental species like Pleurozium schreberi (red-stemmed feathermoss) andClintonia uniflora (queen’s cup). Douglas-fir is an abundant species in zonal stands,along with western hemlock, redcedar, and variable amounts of amabilis fir. The shrublayer is characterized by Vaccinium alaskaense, V. ovalifolium (oval-leavedblueberry), and Menziesia ferruginea (false azalea). As well as Clintonia uniflora,

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common herbs in the sparse herb layer are Orthilia secunda (one-sided wintergreen),Cornus canadensis (bunchberry), Linnaea borealis (twinflower), and Goodyeraoblongifolia (rattlesnake-plantain). The well-developed moss layer contains Pleuroziumschreberi, Rhytidiadelphus loreus, R. triquetrus (electrified cat’s-tail moss), andRhytidiopsis robusta (pipecleaner moss).

Characteristic soil processes include accumulation of acid organic matter on theforest floor (Mor formation), leaching, eluviation, illuviation, and gleying. The soils ofzonal ecosystems are most often Humo-Ferric Podzols which, with increasingprecipitation, grade into Ferro-Humic Podzols. Many Podzols in the CWH lack aneluvial (Ae) horizon, apparently because, in this part of the soil profile, the heavyleaching is offset by the rapid addition of organic colloids and weathering of iron andaluminum.

Soil-forming processes in the wettest portions of the zone are dominated by thegradual build-up of organic matter at the ground surface. In these areas, zonal soils areusually either folic phases of Podzols (if the organic layer is 15-40 cm thick) orFolisols (organic layer thicker than 40 cm or at least 10 cm thick if over bedrock orfragmental material; see Trowbridge et al. 1985).

Mors are the prevailing humus forms. In the wet climate of this zone, leaching ofnutrients from the mineral soil is rapid. Furthermore, many soils derived from acidicparent materials such as granodiorites are low in clay minerals and poor in nutrientsto begin with. Thus, the pool of nutrients contained in the vegetation and surfaceorganic matter is extremely important in helping to maintain ecosystem productivity,especially on coarse-textured, nutritionally poor soils.

NOTES ON CLASSIFICATION

Analysis of floristic and climatic data suggested two major revisions to the zonalclassification (see Klinka et al. 1990): (1) amalgamation of the former Wetter CDF(CDFb) subzone (Klinka et al. 1984) with the former Vancouver Island Drier MaritimeCWH (CWHa1) variant to form the Very Dry Maritime CWH (CWHxm) subzone; and(2) designation of the former Coastal Cedars — Pine — Hemlock (CCPH) zone (Pojar1983) as the Very Wet Hypermaritime CWH (CWHvh) subzone.

SUBZONES

Ten subzones are delineated in the CWH zone (Table 12). They can be separatedalong gradients of continentality (hypermaritime, maritime, and submaritime subzones)and precipitation (very dry, dry, moist, wet, and very wet) (Figure 20, Table 13).Species characteristic of the hypermaritime subzones include Blechnum spicant,Coptis aspleniifolia (fern-leaved goldthread), Sitka spruce, and Scapania bolanderi, andof the submaritime subzones Clintonia uniflora, Orthilia secunda, and Pleuroziumschreberi. Species characteristic of the drier subzones include Douglas-fir, Polystichum

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munitum (sword fern), and Pteridium aquilinum (bracken), and of the wetter subzones,amabilis fir, Menziesia ferruginea, Vaccinium alaskaense, and V. ovalifolium.

The hypermaritime subzones occur on the outer mainland coast, on the outer westcoast of Vancouver Island, and on the Queen Charlotte Islands, while thesubmaritime subzones are restricted to the leeward side of the Coast Mountains. Thedrier subzones are found only in the central and southern portion of the zone — in therain shadows of the Olympic Mountains, Vancouver Island Ranges, and CoastMountains.

TABLE 12. Synopsis of subzones in the Coastal Western Hemlock zone (CWH)

Subzone Code Old code

Wet Hypermaritime CWH CWHwh (g/e/qc)Very Wet Hypermaritime CWH CWHvh (d/CCPH)Very Dry Maritime CWH CWHxm (a1/CDFb)Dry Maritime CWH CWHdm (a2)Moist Maritime CWH CWHmm (b3/b4)Wet Maritime CWH CWHwm (j)Very Wet Maritime CWH CWHvm (b1/b2/i1/i2)Dry Submaritime CWH CWHds (c/h1/h2)Moist Submaritime CWH CWHms (b5/b6/h3)Wet Submaritime CWH CWHws (b7/i3/f1/f2)

SOME REPRESENTATIVE SITE ASSOCIATIONS

The site associations described below form a typical sequence in the CWHdmsubzone (Figure 21).

Western hemlock — Flat moss

The Western hemlock — Flat moss association includes slightly dry to fresh andnutrient-very poor to -medium soils that occur on well to moderately well drained,middle slopes and gently sloping heights of land. The associated soils are sandy- toloamy-skeletal, moderately deep to deep, Orthic Humo-Ferric Podzols with Humimorhumus forms. Relative to other sites, there are neither significant losses nor additionsof moisture and nutrients; therefore, vegetation and soils of this associationapproximate the zonal ecosystem for the CWHdm subzone.

Mature stands are usually well stocked with Douglas-fir, western hemlock, andwestern redcedar (in the lower tree stratum). Both Douglas-fir and western hemlockcan form pure stands in secondary succession.

The shrub layer is usually poorly developed in fully stocked stands. There isalways advance regeneration of western hemlock; occurrence of Acer circinatum (vinemaple), Gaultheria shallon, Mahonia nervosa, and Vaccinium parvifolium depends on

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102

103

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light in the understory and surface materials. Similarly, the herb layer is very poorlydeveloped with infrequent Linnaea borealis, Polystichum munitum, Rubus ursinus(trailing blackberry), and Trientalis latifolia (broad-leaved starflower). The moss layeris well developed, featuring Kindbergia oregana in early successional stages, andHylocomium splendens, Rhytidiadelphus loreus, and Plagiothecium undulatum (flatmoss) in late successional stages.

Douglas-fir — Western hemlock — Salal

This association includes moderately dry and nutrient-very poor to -medium,water-shedding sites that occur on rapidly drained, coarse-skeletal soil materials onupper slopes or valley bottoms in the CWHxm, CWHmm, and CWHdm. Soils aremoderately deep Orthic Humo-Ferric Podzols with Hemimor humus forms. Agrowing-season water deficit and severe nitrogen deficiency are the main constraintsto better forest growth.

Mature stands are usually well stocked with Douglas-fir (in the upper treestratum), western hemlock, and western redcedar (in the lower tree stratum).

The shrub layer is very well developed with Gaultheria shallon (salal) dominantand Mahonia nervosa and Vaccinium parvifolium scattered. Advance regeneration ofwestern hemlock and western redcedar is common in late-seral stands. The herblayer is very poorly developed, with Pteridium aquilinum as the only constantspecies. The moderately developed moss layer includes primarily Kindbergia oreganaand Hylocomium splendens; lichens and xerophytic mosses are infrequent.

Redcedar — Lady fern

This association includes moist to very moist and nutrient-rich to -very rich,water-receiving sites that occur on imperfectly drained lower slopes in the CWHxmand CWHdm subzones. The associated soils are sandy- to loamy-skeletal, moderatelydeep to deep Sombric Humo-Ferric Podzols with Moder or Mull humus forms.Relative to other sites, the soils are either inherently nutrient-rich or enriched byseepage. Under these climatic and edaphic conditions, Douglas-fir and westernredcedar attain their best growth.

Second-growth stands usually feature Douglas-fir; however, the presence ofwestern redcedar stumps suggests that the final stage of secondary succession will bedominated by the latter, shade-tolerant species.

Acer circinatum and Rubus spectabilis (salmonberry) dominate the well-developed shrub layer. In the floristically rich herb layer, the constant species areAthyriumfilix-femina (lady fern), Galium triflorum (sweet-scented bedstraw), Polystichummunitum, and Tiarella trifoliata (three-leaved foamflower). In the less well-developedmoss layer, Leucolepis menziesii (palm tree moss) and Plagiomnium insigneindicate friable forest floors.

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Redcedar — Sitka spruce — Skunk cabbage

Wet and nutrient-medium to -very rich sites throughout lower elevations of theCWH are represented by the Redcedar — Sitka spruce — Skunk cabbage association.These water-collecting sites occur on lower slopes below the Redcedar — Lady fernsite association or in depressions. The associated soils are poorly drained Gleysols orHumisols affected by slowly moving seepage.

Western redcedar and western hemlock dominate the open canopy, reflecting thepattern of relatively drier (usually raised organic mounds) and depressionalmicrosites.

Gaultheria shallon, Vaccinium parvifolium (on acid organic mounds), and Rubusspectabilis (in depressions) dominate the moderately well-developed shrub layer.Herbs are largely confined to depressions and include Athyrium filix-femina,Lysichiton americanum (skunk cabbage), Streptopus amplexifolius (clasping-leavedtwistedstalk), and Tiarella trifoliata. The moderately well-developed moss layer isdominated by Hylocomium splendens, Rhytidiadelphus loreus, and Plagiotheciumundulatum on acid organic mounds, and by Conocephalum conicum, Kindbergiapraelonga, Pellia epiphylla, and Rhizomnium magnifolium in depressions.

WILDLIFE HABITATS

The factors that most influence the assemblage of wildlife species in this zone(Table 14) are: its location and distribution — sea level to 1050 m on windwardslopes and from southern Vancouver Island and the Fraser Lowland north to Alaska;the landforms that range among small coastal islands, coastal plains, estuaries,bedrock-controlled, rolling uplands and steep, rugged mountain slopes, often withexposed bedrock; the cool, mild, maritime climate; and the usually dense coniferousforests. In addition, this zone probably has a greater diversity and abundance ofhabitat elements than any other zone in the province. The greatest diversity of birds,amphibians, and reptiles in British Columbia is found within the Fraser Lowlandportion of this zone, and almost all of the coastal, colony-nesting bird habitats arefound in the CWH.

Black-tailed Deer, Black Bear, Grizzly Bear, and Gray Wolf are the most commonlarge mammals. Black Bear occur throughout, as do Black-tailed Deer (since theywere introduced to the Queen Charlotte Islands). Gray Wolf are only absent from theQueen Charlotte Islands, and Grizzly Bear and Mountain Goat occur only on themainland. The marine environment, including the small, rocky coastal islands,provides good protection from predators and nesting habitat for many species ofcolony-nesting marine birds. Low, near-tidal islets are important haul-out areas forCalifornia and Steller’s Sea-lion, Harbor Seal, Northern Fur Seal, and NorthernElephant Seal. Mountain Goat occupy rugged southerly aspects with exposedbedrock, often descending to forested cliffs near sea level in the winter.

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TABLE 14. Selected wildlife habitats and species in the Coastal Western Hemlock zone(adapted from Wildlife Branch 1989)

Habitat Habitat Representative wildlife species Wildlife species at riska

distribution

Old-growth Limited Mountain Goat, Black-tailed Deer, ∇ Keen’s Long-eared Myotis,coniferous areal extent, Black Bear, Cougar, Gray Wolf, Spotted Owl, Marbled Murreletforests dwindling Marten, California Myotis,

Douglas Squirrel, Columbian Mouse, ♦ Roosevelt Elk, Grizzly Bear,Southern Red-backed Vole, Deer Mouse Mountain Beaver, Townsend’s

Chipmunk, Sitka Mouse,Great Horned Owl, Saw-whet Owl, Barred Owl, Shrew-mole, Trowbridge’s Shrew,Blue Grouse, Ruffed Grouse, Band-tailed Bald Eagle, Tailed Frog, Pacific GiantPigeon, Pileated Woodpecker, Northern Flicker, Salamander, Clouded SalamanderHairy Woodpecker, Common Raven, Gray Jay,Steller’s Jay, Varied Thrush, Chestnut-backedChickadee, Red-breasted Nuthatch, Winter Wren,Vaux’s Swift

Western Toad, Pacific Treefrog, Western Red-backed Salamander, Ensatina Salamander,Northwestern Salamander

Young seral Extensive Black-tailed Deer, Black Bear, ♦ Roosevelt Elk, Grizzly Bearand managed Cougar, Gray Wolf, Marten,second-growth Columbian Mouse, Deer Mouseforests Great Horned Owl, Barred Owl, Blue Grouse,

Ruffed Grouse, Band-tailed Pigeon, NorthernFlicker, Hairy Woodpecker, Common Raven, GrayJay, Steller’s Jay, Chestnut-backed Chickadee,Red-breasted Nuthatch, Winter Wren, VariedThrush

Western Toad, Pacific Treefrog, Western Red-backed Salamander, Ensatina Salamander,Northwestern Salamander

Mixed Common Black-tailed Deer, Black Bear, ∇ Marbled Murreletconiferous Gray Wolf, Marten, California Myotis,and deciduous Douglas Squirrel, Columbian Mouse, ♦ Roosevelt Elkforests Deer Mouse

Red-tailed Hawk, Northern Saw-whet Owl, BlueGrouse, Common Merganser, Steller’s Jay, HairyWoodpecker, Pine Grosbeak, Townsend’s Warbler

Northern Alligator Lizard, Pacific Treefrog,Ensatina Salamander, Northwestern Salamander

Rocky cliffs, Extensive Mountain Goat, Little Brown Myotis, ∇ Keen’s Long-eared Myotistalus, and Common Pika, Northwesternsparsely Chipmunk, Bushy-tailed Woodratvegetated rocks

Common Raven, Black Swift, Cliff Swallow

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TABLE 14. Continued

Habitat Habitat Representative wildlife species Wildlife species at riska

distribution

Avalanche Common Black-tailed Deer, Black Bear ∇ Vancouver Island Marmottracks andseepage sites Blue Grouse, Lewis’ Woodpecker, ♦ Grizzly Bear, Mountain Beaver

Band-tailed Pigeon, Willow Flycatcher,Swainson’s Thrush, Cedar Waxwing,Purple Finch

Red-legged Frog

Upland Rare Northern Saw-whet Owl, ♦ Least Sandpiper, Purple Martingrassy areas Lincoln Sparrow

Agricultural Extensive Coyote, Spotted Skunk, ♦ Mountain Beaver, Shrew-Mole,areas in lowland Coast Mole Townsend’s Mole, Common

areas Barn-Owl, Purple MartinCooper’s Hawk, Red-tailed Hawk, Rough-legged Hawk, Northern Harrier, Short-earedOwl, Mew Gull, Glaucous-winged Gull,Northwestern Crow, Brewer’s Blackbird

Riparian areas, Common Black-tailed Deer, Black Bear, ♦ Roosevelt Elk, Grizzly Bear,wetlands, Gray Wolf, River Otter, Mink, Mountain Beaver, Townsend’smeadows, Deer Mouse, Wandering Shrew Chipmunk, Pacific Jumpingfloodplains, Mouse, Pacific Water Shrew,lakes, and Osprey, Short-eared Owl, Bald Eagle, Great Blue Heron,streams Snowy Owl, Ruffed Grouse, Green-backed Heron, Yellow-

Trumpeter Swan, Sandhill Crane, headed Blackbird, Purple Martin,Ring-necked Duck, Redhead, Tailed Frog, Pacific GiantHarlequin Duck, Wood Duck, SalamanderRed-throated Loon, Common Merganser,Wilson’s Phalarope, Black Tern, Mew Gull,American Dipper

Common Garter Snake, Western GarterSnake, Northwestern Garter Snake, PaintedTurtle, Western Toad, Bullfrog, Red-leggedFrog, Northwestern Salamander, Long-toedSalamander, Rough-skinned Newt

Offshore Common ♦ Bald Eagle, Peale’s Peregrineforested Falcon, Ancient Murrelet,islands Rhinocerous Auklet, Cassin’s Auklet,

Parakeet Auklet, Fork-tailed Storm-Petrel,Leach’s Storm-Petrel

Offshore Limited ♦ Peale’s Peregrine Falcon,grassy and areal extent Rhinocerous Auklet, Fork-tailedshrubby Storm-Petrel, Leach’s Storm Petrel,islands Tufted Puffin, Cassin’s Auklet

Marine Common Northern Sea Lion, Northern Fur ∇ Keen’s Long-eared Myotis,cliffs and Seal, Northern Elephant Seal, Horned Puffin, Thick-billed Murrerocky islets Harbor Seal

Black-legged Kittiwake, Black ♦ Bald Eagle, Peale’s PeregrineOystercatcher, Double-crested Falcon, Brandt’s Cormorant,Cormorant, Pelagic Cormorant, Pigeon Common MurreGuillemot, Glaucous-winged Gull, Black Swift

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TABLE 14. Continued

Habitat Habitat Representative wildlife species Wildlife species at riska

distribution

Estuaries, Limited Black-tailed Deer, Black Bear, ∇ Sea Otter, Marbled Murreletshallow bays, areal extent Gray Wolf, Raccoon, Mink,intertidal and River Otter, Northern Sea Lion, ♦ Roosevelt Elk, Grizzly Bear,sub-tidal Harbor Seal, Killer Whale, Bald Eagle, Great Blue Heron,marine Harbor Porpoise Common Murre, Ancient Murrelet,

Rhinoceros Auklet, Cassin’s Auklet,Northern Pygmy-owl, Sharp-shinned Parakeet AukletHawk, Red-throated Loon, Yellow-throated Loon,Trumpeter Swan, Canada Goose, Brant, Barrow’sGoldeneye, Black Scoter, Surf Scoter, White-winged Scoter, Mallard, Northern Shoveller,American Wigeon, Green-winged Teal, PigeonGuillemot, Northwestern Crow

a Wildlife species and subspecies at risk are those on the preliminary Red and Blue Lists proposed in the Provincial WildlifeStrategy, B.C. Ministry of Environment (October 1989 draft).

∇ Red-listed wildlife species. These are being considered by the Wildlife Branch for designation as endangered or threatenedin British Columbia.

♦ Blue-listed wildlife species. The Wildlife Branch considers these species ‘‘sensitive’’ and/or deserving of managementattention. Population viability is a concern for these species because of (a) major declines in population numbers; or (b)major changes in habitat that will further reduce existing distribution. Species that are generally suspected of beingvulnerable, but for which information is too limited to allow designation in another category, are included in this category.

Climax or old-growth forests provide both food and nesting habitat for a large varietyof birds. The deep, dense canopy is an excellent interceptor of snow, while litterfall ofarboreal lichens and needles provides winter forage for Black-tailed Deer. Afterclearcutting, the succulent regrowth provides an abundance of forage for Black-tailedDeer, Black Bear, Grizzly Bear, and Roosevelt Elk (on Vancouver Island), as well ashabitat for Blue Grouse, Band-tailed Pigeon, Lewis’ Woodpecker, Traill’s Flycatcher,American Robin, Swainson’s Thrush, Cedar Waxwing, and Purple Finch. Forestregeneration is usually rapid and forest openings can quickly develop a dense canopy ofyoung trees with sparse understory vegetation. Many species of birds, such as SpottedOwl, Great Horned Owl, Saw-whet Owl, Northern Flicker, Pileated Woodpecker, HairyWoodpecker, Hammond’s Flycatcher, Gray Jay, Steller’s Jay, Common Raven, Chestnut-backed Chickadee, Red-breasted Nuthatch, Winter Wren, and Varied Thrush, use theconifer forests because of the presence of other birds and rodents, bark and wood-boringinsects, and conifer seeds. Many species of amphibians occur because of the damp litteron the floor of mature forests, including Northwestern Salamander, Western Red-backedSalamander, Ensatina Salamander, Clouded Salamander, and Western Toad. The PacificGiant Salamander and Tailed Frog both require steep cold mountain streams in old-growth forests as breeding habitat, and damp litter on the forest floor to survive asmetamorphosed adults.

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Many large and small rivers cross this zone, with large and small riparian areas.Nearly all the rivers and streams are used for spawning by salmon, and most of theiryoung spend some time in these streams. These fish, in addition to the lushvegetation and berries, provide ample food for Grizzly Bear and Black Bear. Theseriparian areas support some of the densest populations of Grizzly Bear and Black Bear inthe province. Other species that depend on the anadromous fish are River Otter, Mink,Common Merganser, Common Goldeneye, Bald Eagle, and many species of gulls. Theannual Eulichan (candlefish) run also provides a spring feast for seals, sea lions, gulls,and Bald Eagle on the lower reaches of many coastal rivers. Many species of reptiles andamphibians use riparian areas and wetlands within the forest, including the CommonGarter Snake, Western Terrestrial Garter Snake, and Red-legged Frog, although theQueen Charlotte Islands have no reptiles and only one amphibian —the Northern Toad.

As these rivers and streams enter the marine environment they form estuaries,which, like the rivers behind them, range from small to very large (e.g., the Fraser Riverestuary). The nutrient-rich, protected waters of these estuaries provide shelter for over-wintering waterbirds, such as diving and dabbling ducks, Trumpeter Swan, grebes,scoters, and gulls. Most of the province’s estuaries occur in this zone.

Steep, rocky islets are used by colony nesting seabirds such as the Pelagic andDouble-crested Cormorants, Ancient Murrelet, Forked-tailed Storm-Petrel, Leach’s Storm-Petrel, Cassin’s Auklet, Rhinocerous Auklet, Pigeon Guillemot, Tufted Puffin, andCommon Murre. Peale’s Peregrine Falcon nest on rocky ledges near colonies of AncientMurrelets on the Queen Charlotte Islands, and Bald Eagle perch on large conifers alongmajor rivers and on the forested islets and headlands.

Extensive areas of sparsely vegetated, steep rock occur in many of the fjords in thiszone. The massive rock walls are poor habitat for most wildlife species, except MountainGoat which sometimes use these areas as escape terrain.

Extensive urban and agriculture developments have taken place in the FraserLowland, displacing large mammals such as Roosevelt Elk, Grizzly Bear, and Gray Wolf.While Black-tailed Deer, Cougar, and Black Bear survive here, their numbers are greatlyreduced. Draining of wetlands, especially Sumas Lake, and diking of the Fraser River,which has subsequently stopped the development of back-channels and sloughs, hasreduced the number of over-wintering waterbirds. There has been minor compensationwhen forest has been turned into agricultural land, enabling these birds to feed onexposed crops and insects.

The extensive urban areas in the Lower Mainland portion of this zone support avariety of native and introduced wildlife species whose abundance and diversity arerelated to the density of development. Non-native species include the Rock Dove,House Sparrow, European Starling, Crested Myna, Gray Squirrel, Roof Rat, NorwayRat, and House Mouse. Native species that have adapted to urban habitats includethe Black-tailed Deer, Coyote, Striped Skunk, Raccoon, Little Brown Myotis, Herring

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Gull, Common Nighthawk, Barn Owl, and Barn Swallow. Even these urban species aremore abundant in areas that are interspersed with parks, gardens, andnative forest.

Several animal species have been introduced to certain parts of the CWH. On theQueen Charlotte Islands, Rocky Mountain Elk, Black-tailed Deer, Raccoon, Beaver, andPacific Treefrog have all been directly introduced. Roosevelt Elk were directly introducedto the Sechelt Peninsula, and Gray Squirrel to the Lower Mainland. The Spotted Skunkand North American Opossum were introduced to Washington State and have sinceexpanded their range into the Lower Mainland. The Crested Myna maintains a smallpopulation near urban areas centred around Greater Vancouver, but it has not expandedits range much since being introduced in the 1890’s. In contrast, the European Starlingextended its range during a similar time period from the Eastern United States to thewest coast of North America, including the Coastal Western Hemlock zone.

The only subspecies to have recently become extinct in this zone is the DawsonCaribou, from the Queen Charlotte Islands.

RESOURCE VALUES

The CWH is the most productive forest region in Canada. In the drier portion of thezone, Douglas-fir, grand fir, western white pine, and western redcedar, and in the wetterportion, amabilis fir, Sitka spruce, western hemlock, and yellow-cedar, exhibit their bestgrowth. Thus, a majority of CWH ecosystems are used primarily for forestry, amanagement strategy that warrants the application of intensified silvicultural practices.As a result of mountainous relief and high precipitation, soil conservation appears to bethe primary management concern in sustaining the productive potential of forestecosystems.

Medium- to fine-textured, coarse fragment-free soils in the driest portion of the zoneare suitable for agriculture. However, the combination of unfavourable topography andhumid climate renders most of the zone unsuitable for agricultural use.

Recreational pursuits in the CWH include hiking, hunting, fishing, and wildlifeviewing. Marine-based sports such as sea-kayaking, boating, and sailing are very pleasantalong the scenic coastline of much of the zone. ‘‘Big trees’’ are common in this zone andare a very popular recreational destination.

Although there is an abundance of furbearers in this zone, fur harvest isgenerally low.

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LITERATURE CITED

Klinka, K., R.N. Green, P.J. Courtin, and F.C. Nuszdorfer. 1984. Site diagnosis, treespecies selection, and slashburning guidelines for the Vancouver Forest Region. B.C.Min. For., Land Manage. Rep. No. 25. Victoria, B.C.

Klinka, K., J. Pojar, and D.V. Meidinger. 1990. Revision of biogeoclimatic units of coastalBritish Columbia. Northwest Sci. 64 (In print).

Pojar, J. 1983. Coastal Cedars — Pine — Hemlock biogeoclimatic zone (CCPH). InForestry handbook for British Columbia. 4th ed. S.B. Watts (editor). D.W. Friesen &Sons Ltd., Cloverdale, B.C., pp. 258-263.

Rose, M.S. and C. Grant. 1976. Remote station climate prediction model. B.C. Environ.Land Use Comm. Secr., Data Serv. Div., Victoria, B.C.

Trowbridge, R., H. Luttmerding, and C. Tarnocai. 1985. Report on folisolic soilclassification in Canada. In Expert Committee on Soil Survey, Proc. Sixth Ann.Meeting, Guelph, Ont., Nov. 26-30, 1984. J.A. Shields and D.J. Kroetsch (editors).Agric. Can., Res. Br., Ottawa, Ont., pp. 180-204.

Wildlife Branch. 1989. Regional wildlife habitat maps. B.C. Min. Environ., Victoria, B.C.15 maps, 1:500000.

4.2.2 CWH Coastal Western Hemlock Zone

Location and Distribution: (Figure 4.4; Table 4.2) The CWH is the zoneof low- to middle-elevation forest occupying the coastal islands andmainland of the Hecate Lowland and the river valleys of the CoastMountain Range. In some areas, particularly along major river systems likethe Skeena and Nass, the CWH extends inland as far as the western slopesof the Hazelton and Skeena mountains. The CWH makes up 22.1% of theland area in the south half of the PRFR, mainly within the North Coast andKalum forest districts, with small portions in the western Kispiox, Bulkley,and Morice forest districts, and in Tweedsmuir Provincial Park.

The CWH ranges in elevation from sea level to 1000 m. The exactelevational range varies considerably with local climate and topography. Onthe outer coast, the CWH is usually found between 0 and 600 m elevation,below the MH zone. In the inland valleys of the Hazelton Mountains it isfound in the 600 - 1000 m elevation band, sandwiched between the ICH andESSF zones. In heavily glaciated areas (e.g., near Stewart), it may onlyextend to 400 m elevation.

Climate: (Table 4.3) The CWH has a mostly maritime or oceanic climatewith relatively mild temperatures and heavy rainfall. The growing season isthe longest in the PRFR, but summers tend to be cool and cloudy, ratherthan warm and sunny. Winters are extremely wet and quite mild, exceptwhen frigid Arctic weather systems cover the entire region. Low-elevationcoastal areas receive very little snow. With increasing distance from thecoast, the temperature extremes become greater, the summers becomedrier, and more of the precipitation falls as snow. Over most of the CWH,the soil does not freeze significantly during a normal winter.

Vegetation: (Figure 4.5) The natural vegetation of the CWH is dominatedby old-growth conifer stands (rainforests) of western hemlock, westernredcedar, and amabilis fir. Sitka spruce (Roche spruce inland) is commonbut never dominant, and occurs mainly on alluvial soils. Shore pine andyellow-cedar are abundant on the outer coast where a scrubby forest growson organic soils over bedrock. Douglas-fir is present around Kemano, alongGardner Canal, and in the Hower Kitlope valley. Deciduous trees areuncommon naturally, occurring mainly on floodplains and on landslidescars where disturbance exposes mineral soil. Red alder is the dominanthardwood on the outer coast; black cottonwood is more common inland.

Understory vegetation on zonal sites is dominated by Alaskan blueberry,oval-leaved blueberry, red huckleberry, and false azalea, scatteredthroughout with small herbs (five-leaved bramble, cordilleran bunchberry,deer fern, spiny wood fern, queen’s cup, false lily-of-the-valley, and rosytwistedstalk). A carpet of feathermosses and leafy liverworts (typicallylanky moss, step moss, flat moss, Scapania bolanderi, and cedar-shakeliverwort) covers the forest floor. Another characteristic feature is the

CWH

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FIGURE 4.4. Distribution of CWH subzones in the PRFR, south half.

abundance of mosses and liverworts growing on the trees. Commonunderstory species on wetter sites include devil’s club, salmonberry, ladyfern, oak fern, skunk cabbage, and leafy and sphagnum mosses.

Because fires occur rarely in our CWH, seral stands were uncommon beforeclearcut logging began on a large scale. Across most of the zone,shade-tolerant conifers such as western hemlock, amabilis fir, and westernredcedar dominate young stands and regenerate quickly after clearcuttingor windthrow. Inland, however, some south-facing slopes and drier valleyssuch as the Kitsumkalum have a history of fire. Lodgepole pine, paperbirch, and trembling aspen are well established in such areas. Also, onproductive riparian ecosystems, tall shrubs (willows, salmonberry,thimbleberry, red elderberry, highbush-cranberry, black twinberry, red-osier dogwood, and Ribes spp.) and deciduous trees (red alder and blackcottonwood) often dominate early successional stages.

Soils: (Table 4.2) Cool, wet weather and granitic parent materials are thetwo dominant features shaping the soils of the CWH in the PRFR. Thesetwo factors combine to produce strongly leached, nutrient-deficient mineralsoils with a thick accumulation of acidic organic forest floor. Plant roots aremainly located within the forest floor layers; this is where most of thenutrient cycling takes place. Zonal soils are mainly classified as Ferro-Humic and Humo-Ferric Podzols with Humimor and Hemihumimor humusforms. Folisols are dominant where organic layers are exceptionally thick(>30 cm) or mineral soils are very shallow over bedrock. Other commonsoils include Regosols or Brunisols on floodplains and Gleysols on wet sites.

Differentiating Features: The CWH can be distinguished from the MHzone, which lies above it, by the pre-eminence of western hemlock overmountain hemlock, especially in regeneration layers, and by the presence ofwestern redcedar. It can be distinguished from the ICH zone by thepresence of red alder and red huckleberry, the abundance of amabilis fir(except in the CWHwm) and lanky moss, and the scarcity of subalpine fir,black huckleberry, and knight’s plume on zonal ecosystems.

Subzones and Variants: (Figures 4.4 and 4.5; Table 4.4) Four subzones ofthe CWH have been identified in the south half of the PRFR. Most of thesehave been further subdivided into variants, for a total of six biogeoclimaticunits:

CWHvh - Very Wet Hypermaritime subzone CWHvh2 - Central variant

CWHvm - Very Wet Maritime subzone CWHvm1 - Submontane variant CWHvm2 - Montane variant

CWHwm - Wet Maritime subzone

CWHws - Wet Submaritime subzone CWHws1 - Submontane variant CWHws2 - Montane variant

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CWHwm CWHws1 CWHws2

78 013 88 237 171 81 474 814 180.7% 2.1 % 4.3 %0 - 600 m 10 - 600 m 600 - 1000 m

Coast Mtns.; northern Eastern slopes of Coast Eastern slopes of CoastKitimat Ranges and Mtns., Kitimat Ranges Mtns., Kitimat Rangessouthern Boundary and western slopes of and western slopes ofRanges Hazelton Mtns. Hazelton Mtns.

Khutzeymateen R., Kitimat and Above CWHws1; alsoKateen R., Kitsumkalum valleys; inland to Kitwanga andObservatory Inlet, Skeena R. from Cranberry R. and southPortland Canal Exstew R. to Legate to shores of Morice,

Ck.; Nass R. below Tahtsa, Whitesail andTseax R. Eutsuk lakes and upper

Kitlope and Gamsby r.

Wet, humid, mild Submaritime or Wetter, with a cooler,maritime, with heavier coastal-transitional; shorter growing seasonsnow and a shorter warm, moist summers and heavier snowpacksgrowing season than with significant dry than the CWHws 1more southerly spells; winters are thesubzones coldest and driest in

the CWH

Humo-Ferric and Orthic Humo-Ferric Orthic Humo-Ferric andFerro-Humic Podzols; Podzols Ferro-Humic PodzolsTypic Folisols

Humimors; Orthihemimors; Orthihemimors;Hemihumimors; often 5 - 20 cm thick Orthihemihumimors;compacted by snow 3 - 13 cm thick

Hw, Ss Hw, Ba, Cw, Ss, Sxs Hw, Ba, Hm

Dr, Act Dr, Act, Pl, Ep, At Bl

HwSs - Blueberry HwBa - Bramble HwBa - Bramble

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4 • 21

ICH ESSF CWH MH

100 367 ha 601 407 ha 175 670 ha 220 680 ha0.7% 4.3% 1.2% 1.6%100 - 900 m 800 - 1500 m 0 - 450 m 400 - 1000 m

Eastern valleys of Northernmost Skeena Coast Mtns., Boundary Coast Mtns., BoundaryCoast Mtns., Bound- Mtns.; eastern slopes Ranges, St. Elias Mtns. Ranges, St. Elias Mtns.ary Ranges of Coast Mtns.,

Boundary Ranges

Lower slopes and Gentle to steep, rocky Steep, lower slopes and Steep, heavily glaciatedfloors of major river mountain slopes floors of heavily mountain slopesvalleys glaciated river valleys

Transitional; continen- Interior subalpine; Submaritime; cool, Coastal subalpine; wet,tal but moderated by long, cold snowy moist summers and wet, snowy winters and short,strong coastal influ- winters and short, very snowy winters; cool, wet summers;ences; cool, moist cool, rather wet most valleys lie in strongly influenced bysummers and cold, summers rainshadow of the Coast surrounding glacierssnowy winters Mtns. and are strongly

influenced by nearbyglaciers

Brunisolic Gray Ferro-Humic Podzols Humo-Ferric Podzols Ferro-Humic and HumoLuvisols; Dystric Ferric PodzolsBrunisols

Hemimors and Hemihumimors; Hemimors and Humimors andHemihumimors; 5 - 15 cm thick Mormoders Hemihumimors;> 10 cm thick 5 - 15 cm thick

Hw, Bl, Sx, Pl Bl, Hm, Sxw, Hw Hw, Ss, Bl Hm, Bl, HwAt, Act, Ep -- Act, Dr --

All Zones — North

4 • 61

a Bars indicate the relative abundance of plants across all site series within a biogeoclimatic unit. These bars are defined in Section 3.2.2, page 3•6.

FIGURE 4.13. Vegetation table for all forested zones in the PRFR, north half.

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a Bars indicate the relative abundance of plants across all site series within a biogeoclimatic unit. These bars are defined in Section 3.2.2, page 3•6.

FIGURE 4.13. (Continued)

All Z

ones —

North

4 • 65

4.3.3 CWH Coastal Western Hemlock Zone

Location and Distribution: (Figure 4.16; Table 4.8). The CWH occurs atlow to middle elevations mostly west of the crest of the Coast Mountains.There is not much CWH in the north half of the PRFR (1.2%). The mostsignificant areas of the zone occur along the lower stretches of the Unuk,Iskut - Stikine, Whiting, and Uaku drainages, along with some pockets inthe eastern Haines Triangle. The CWH occupies elevations from near sealevel to 300 - 450 m.

Climate: (Table 4.9) This northern portion of the CWH lies inland of theAlaska Panhandle, where it has no contact with the ocean. It ischaracterized by a submaritime, humid (snowy) climate. Stewart is theclosest long-term, Canadian climate station, but comparisons with datafrom Alaskan stations such as Juneau and Wrangell and a short-termstation at Bronson Creek indicate that it has a representative climate forthe zone. Mean annual temperature at Stewart is 5.1° C. Averagetemperature is above 10° C for 4 months of the year and below 0° C for 3months. Mean annual precipitation is 1843 mm; mean annual snowfall is532 cm. The summer is cool and moist, fall is very wet, and winter is cooland has heavy, wet snowfalls. Local climate in the northern CWH is verystrongly affected by cold air from the massive surrounding icefields thatextend in many places to the valley floor.

Vegetation: (Figure 4.13) The CWH in the Cassiar Forest District differsfrom the southern CWH in that two key species, amabilis fir and westernredcedar, are absent. Yellow-cedar is also absent. Most of the zone iscovered by closed forests dominated by western hemlock and containingvariable amounts of Sitka spruce. Sitka spruce is most abundant on alluvialterraces bordering the broad, braided riverbeds. Black cottonwood formsextensive stands on floodplains that occupy much of the valley bottomsalong these braided rivers. Red alder and occasionally paper birch alsooccur in the alluvial forests. Subalpine fir is fairly common as a minorcomponent of many stands, whereas dry, seral lodgepole pine stands areuncommon. Wetlands are uncommon in this zone, but when present areprimarily riparian types.

On zonal ecosystems, Alaskan blueberry is the characteristic dominantshrub. Oval-leaved blueberry, false azalea, and devil’s club are alsofrequent. Typical herbs include five-leaved bramble, bunchberry, oak fern,and one-sided wintergreen. Lanky moss, pipecleaner moss, step moss,knight’s plume, and cedar-shake liverwort are also characteristic. Becauseof the snowy climate and concave, glacial valley profiles, devil’s-clubecosystems are probably more widespread than zonal ecosystems. Inaddition to devil’s club, these moister, richer ecosystems includethimbleberry, black gooseberry, oak fern, spiny wood fern, lady fern, rosytwistedstalk, clasping twistedstalk, three-leaved foamflower, leafy mosses,and ragged mosses. Red-osier dogwood, salmonberry, thimbleberry,highbush-cranberry, and stink currant typically join devil’s club in alluvialforests.

CWH — North

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FIGURE 4.16. Distribution of CWH, ICH, and SBS zones in the PRFR, north half.

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Soils: (Table 4.8) The moderately well-drained soils of zonal ecosystems inthe northern CWH typically are Humo-Ferric Podzols with Hemimor andMormoder humus forms. This characteristic soil profile covers even thedriest ridges and shallow soils over bedrock. A distinctive feature of thisnorthern CWH is the dominant effect of ongoing glacial, fluvial, andcolluvial (avalanche and landslide) activity on soil formation. Thus, much ofthe zone in this area has very young soils (Regosols or Brunisols) that havehad little opportunity to develop since being deposited. The short growingseason and cool climate also slow the rate of biological and chemicalactivity. These soils are often coarse textured (gravels and sands) and maybe deficient in nitrogen until they are colonized by nitrogen-fixing plantssuch as alder.

Differentiating Features: The CWH can be distinguished from the MHzone, which lies above it in elevation, by the pre-eminence of westernhemlock over mountain hemlock, especially in regeneration. It can bedistinguished from the neighbouring ICH zone by the presence of red alder,the dominance of lanky moss, and the relative lack of subalpine fir, blackhuckleberry, and knight’s plume on zonal sites. The CWH can be readilydistinguished from bordering areas of the SBS and BWBS because thesetwo zones lack western hemlock, oval-leaved blueberry, Alaskan blueberry,and lanky moss.

Subzones: The CWH of theCassiar Forest District belongs tothe Wet Maritime subzone(CWHwm). Although the Cassiarportion of the CWHwm likelyrepresents a separate northernvariant of this subzone, we lackthe data to formally recognize anddescribe this variant.

CWH — North

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BGC Units

4 • 80

CWH (fluvial) Interpretations Tablea

Productivityb VegetationSite Site index - ht (m) at 50 yr Limiting factors for potential &series 0 10 20 30 40 productivity and regeneration complexesc

vh2/08 Ss High fluvial benches. Competing Very Highvegetation. High (but seasonally RS, SBfluctuating) water tables may restrictrooting. Moderate flooding/erosionhazard.

vml/09 Ss High fluvial benches. As above. Very HighCA, RS, SB

wm/05 Ss High fluvial benches. As above. Frost/ Very Highcold air in some upper valleys. CA, RS, SB

ws1, Sxs High fluvial benches. As above. Frost/ Very Highws2/07 cold air in some upper valleys CA, RS, SB

(CHWws2).

vh2/09 Ss Middle fluvial benches. Competing Very Highvegetation. High (seasonally fluctuat- RSing) water tables restrict rooting.Frequent (annual) flooding, deposi-tion/erosion.

vm1/10 Ss Middle fluvial benches. As above. Very HighCA

wm/06 Ss Middle fluvial benches. As above. Very HighFrost/cold air in some upper valleys. CA

ws1 Sxs Middle fluvial benches. As above. Very Highws2/08 Frost/cold air in some upper valleys CA

(CWHws2).

vh2/10 no information Low fluvial benches. High water Highvm1/11 tables restrict rooting. Frequent and CA, WIwm/07 prolonged annual flooding, often ofws1, high velocity. Annual deposition/ws2/09 erosion. Competing vegetation.

a Refer to Section 7.2 for an explanation of each category in the table. b Site index estimates are based on (very limited) unpublished Ministry of Forests data. c Vegetation potential and complexes are described in Section 7.2.4, page 7•18.

Silviculture

7• 46

Tree speciesselectionguidelinesd Reforestation considerations

Cw Ss High fluvial benches represent the most productive forested ecosystems in the[Ba] CWH zone. Very high vegetation potential, sensitive soils (erosion, compaction),(Hw) and high wildlife, fisheries, and water values necessitate extremely careful planningHard: Dr and operations on these sites. Refer to Chapter 6 and fisheries, forestry, and wildlife

guidelines for riparian ecosystem management. Harvesting should be carried outquickly during the driest season. Mechanical disturbance and mineral soil exposure

Ba Cc should be minimized. Fine-textured surface horizons should be protected. Decidu-[Ssef] ous seed trees should be controlled in advance of harvest if conifer regeneration is(Hwe) the objective. Intensive vegetation control will be required to establish conifersHard: Act Dr quickly and evenly (herbicides/manual treatments; repeated treatments). Secure

stock early and plant immediately with large, sturdy stock on the most raisedSse microsites. Consider cluster planting (see page 7•15) and reduced stocking to[Bag Cwg Hwe] facilitate spot treatment around seedlings (fewer, more intensively managed plantHard: Act Dr ing spots of 3 - 5 seedlings) while maintaining patches of understory for wildlife.

Riparian management guidelines favour partial cutting over clearcutting and thusBa Cw prescribed fire is generally impractical as a vegetation management tool (although it[Blh Sxsef] has been shown to be effective on fluvial sites in the CWHvm). Shade-tolerant Cw(Hwc) and Ba are viable alternatives to Ss/Sxs, considering weevil and Porcupine hazardHard: Act Dr and vegetation competition. Hardwood management should be considered on many

sites.

Ss Middle fluvial benches are also extremely productive and present many of the same[Ba Cw] concerns noted above for high fluvial benches. Establishment of coniferous planta-(Hw) tions on medium benches, however, is even more problematic due to more frequentHard: Dr surface flooding, and associated sediment erosion /deposition, and extreme compe-

tition from deciduous trees and shrubs. Uncertainty about longevity of mediumbench sites also makes conifer establishment a questionable investment. Most sites

[Ba Cw Ssef] should be managed as pure hardwood (Act/Dr) stands. Middle bench sites are oftenHard: Act Dr more appropriately managed for wildlife, watershed, and aesthetic values (see

Chapter 6).

[Bag Cwg Sse]Hard: Act Dr

[Ba Blh Cw Ssef]Hard: Act Dr

Sites not suitable Low bench sites are not suited to conifer establishment (or commercially viablefor conifers. hardwood establishment) due to the frequent and often high-velocity flooding andHard: Acti Dr resultant erosion /sediment deposition. Do not disturb low bench sites; they are

best managed for wildlife, watershed, and aesthetic values (see Chapter 6).

d Species are in alphabetical order within primary, secondary [ ], and tertiary ( ) categories. SeeSection 7.2.5, page 7•22. Tree species codes are described in Appendix 3.

e Risk of Porcupine damage, especially on Hw, Ss, and Sxs. f Risk of weevil damage on Ss and Sxs. g Ba and Cw do not occur naturally throughout most of the CWHwm. Their use should be

restricted to southern portions.h Bl should be considered on cold air drainage sites.i Act is rare or absent in the CWHvh2.

CWH (fluvial)

7 • 47

TREE

LAYER

SHRUB LAYER

HERB

LAYER

MOSS LAYER

Thuja plicata Tsuga heterophylla

Chamaecyparis nootkatensis Abies amabilis

Picea sitchensis Tsuga mertensiana

Pinus contorta Pseudotsuga menziesii

Menziesia ferruginea Vaccinium alaskaense Vaccinium ovalifolium Vaccinium parvifolium

Gaultheria shallon Vaccinium ovatum Blechnum spicant

Listera cordata Maianthemum dilatatum

Cornus canadensis Rubus pedatus

Linnaea borealis Polystichum munitum

Streptopus roseus Coptis aspleniifolia

Lysichitum americanum Dryopteris expansa

Hylocomium splendens Plagiothecium undulatum Rhizomnium glabrescens

Rhytidiadelphus loreus Scapania bolanderi Kindbergia oregana

Sphagnum girgensohnii Pellia neesiana

Polytrichum alpinum Rhytidiopsis robusta

Clintonia

p

uniflora

western redcedar western hemlock yellow-cedar amabilis fir Sitka spruce mountain hemlock shore/lodgepole pine Douglas-fir false azalea Alaskan blueberry oval-leaved blueberry red huckleberry salal evergreen huckleberry deer fern heart-leaved twayblade false lily-of-the-valley bunchberry five-leaved bramble twinflower sword fern rosy twistedstalk fern-leaved goldthread skunk cabbage spiny wood fern queen's cup step moss flat moss large leafy moss lanky moss scapania Oregon beaked moss common green sphagnum shiny liverwort stiff-leaved haircap moss pipecleaner moss

Biogeoclimatic Unit CWHvm1 CWHvm2 CWHvh1 CWHvh2 CWHwh1 CWHwh2 TA

BLE

14. Vegetation table for zonal sites of w

et and very wet

hypermaritim

e and very wet m

aritime C

WH

variants

38

237

• Western wolverine (Blue)• Vancouver Island wolverine (Red)• Keen's long-eared myotis (Red)• cougar (Yellow)• black-tailed deer (Yellow)

COASTAL WESTERN HEMLOCK ZONE

The CWH is rich in species compared to interior and northern areas owingto the great diversity and abundance of habitat elements. Habitats such asbogs, talus slopes, small coastal islands, coastal plains, estuaries,avalanche tracks, and large areas of contiguous forest contribute to therich biodiversity of this zone. The range in elevation (sea level to 1050 m)and the mild maritime climate are also important features. Many birdspecies winter in this zone.

Old-growth forests provide food and nesting habitat for a widevariety of birds. Some species such as the Spotted Owl and MarbledMurrelet appear to be dependent on old growth. Many species ofamphibians, including four species of salamander, are present due to themoist litter and coarse woody debris on the forest floor. The Pacific giantsalamander and tailed frog require steep cold mountain streams in old-growth forests to reproduce. Anadromous salmon are an important sourceof food for many wildlife species.

Black-tailed deer, cougar, black bear, grizzly bear, and graywolf are common large mammals. Hunting for large mammals is acommon recreational pursuit. Fur harvest is low despite large furbearerpopulations.

Some species of management concern are:

• Pacific giant salamander (Red)• tailed frog (Blue)• Spotted Owl (Red)• Marbled Murrelet (Blue)• Peales' Peregrine Falcon (Blue)• Bald Eagle (Blue)• Great Blue Heron (Blue)• Queen Charlotte ermine (Red)• Vancouver Island wolverine (Red)• mountain beaver (Red, in Fraser Valley)

5�4 - 1

C W H

CWHCoastal Western Hemlock Zone

Overview

The Coastal Western Hemlock (CWH) Zone in Britich Columbia occursprimarily in the coastal environments of the Vancouver and PrinceRupert forest regions. It has a very small total area (283 km2) within theCariboo Forest Region in the lower Mosley Creek valley, the HomathkoRiver valley downstream of about Mosley Creek, and at the southern tipof Chilko Lake.

The portion of the CWH Zone within the Cariboo Forest Region istransitional to Interior climates. It is distinguished by the presence ofwestern hemlock, western redcedar, western white pine, amabilis fir, andother coastal species including red huckleberry, red alder, and white-veined wintergreen. Species found in Interior forests, such as red-stemmed feathermoss, are also common. Similar to other submaritimeCWH forests, the understory vegetation is sparse. Common species areblack huckleberry, falsebox, prince�s pine, false azalea, queen�s cup, andbunchberry.

The CWH in the Cariboo Forest Region has not been sufficientlyinventoried to assess subzone boundaries or site series representation.However, based on surveys in adjacent areas of the Vancouver ForestRegion, two variants, the CWHds1 (Dry Submaritime Subzone,Southern Variant) and CWHms1 (Moist Submaritime Subzone, SouthernVariant) may be present in the Cariboo Forest Region. Both would be atthe Interior limits of their extent and are much more extensive in thecoastal environments of the Vancouver Forest Region. In the VancouverForest Region, the CWHds1 occurs in valley bottoms and the CWHms1at higher elevations below the Mountain Hemlock Zone. In the CaribooForest Region, the CWHds1 may occur from valley bottom to theMountain Hemlock Zone or a band of the CWHms1 may occur betweenthe upper elevations of the CWHds1 and lower elevations of theMountain Hemlock Zone.

BGC UNITS

5�4 - 2

Black cottonwoodPopulus balsamifera ssp. trichocarpa

Western white pinePinus monticola

6�5 - 1

C W H

CWHCOASTAL WESTERN HEMLOCK ZONE

The CWH Zone has a very small total area (283 km2) in the CaribooForest Region, where it occurs in valley bottoms and on lower slopes atthe confluence of Mosley Creek and the Homathko River, near theborder with the Vancouver Forest Region. It also includes a small area atthe southern end of Chilko Lake in Ts�yl-os Provincial Park. The CWHin the Cariboo Forest Region has not been sufficiently inventoried toassess subzone boundaries or site series representation. However, basedon surveys in adjacent areas of the Vancouver Forest Region, twosubzone variants, the CWHds1 (Dry Submaritime Subzone, SouthernVariant) and CWHms1 (Moist Submaritime Subzone, Southern Variant)are probably present in the Cariboo Forest Region. Both are at thelimits of their Interior extent and are much more extensive in the coastalenvironments of the Vancouver Forest Region. The CWHds1 likelyoccurs in valley bottoms, while the CWHms1 likely occurs on sideslopes above the CWHds1 and bordering the MH Zone at higherelevations. The CWHms1 probably does not extend as far up theMosley Creek and Homathko River valleys as does the CWHds1.Elevations of the CWH Zone in this Region are from valley bottom toapproximately 1200 m.

Distinguishing Adjacent Units from the CWH (Cariboo ForestRegion only)

The MHmm2 occurs above the CWH Zone in the Homathko Rivervalley and adjacent lowest portions of the Mosley Creek valley. TheESSFxv1 occurs above the CWH Zone further up the Mosley Creekvalley and at the southern end of Chilko Lake. Further into the CaribooForest Region, where the coastal influence on the climate is lessened, theIDFdw replaces the CWH on lower slopes of the Homathko River andMosley Creek valleys. The IDFdw also replaces the CWH Zone alongmost of the Chilko Lake shoreline.

6�5 - 2

SIT

E U

NIT

S

Williams Lake

Alexis Creek

Tatla Lake

Anahim Lake

0 10 20 km.

Distribution of CWH Zone in the Cariboo Forest Region

6�5 - 3

C W H

In the MHmm2, zonal sites have:� mountain hemlock;� little or no Douglas-fir or redcedar.

In the ESSFxv1, zonal sites have:� grouseberry and cladonia lichens;� common subalpine fir, Engelmann spruce, and grouseberry;� little or no western hemlock or redcedar.

In the IDFdw, zonal sites have:� little or no western hemlock or redcedar;� soopolallie, pinegrass, and often kinnikinnick.

Site Units of the CWH

Site units of the CWHds1 and CWHms1 have been described for theVancouver Forest Region by Green and Klinka (1994). Separateclassifications have not been prepared for the Cariboo Forest Region norhas the Vancouver Region classification been tested in the Cariboo ForestRegion. However, it is anticipated that the Vancouver Region classifica-tions are generally applicable to the Cariboo Forest Region. Due to thecurrent lack of information on the boundary between the CWHds1 andCWHms1 in the Cariboo Forest Region, any site identification efforts inthis Region should consider both the CWHds1 and CWHms1 classifica-tions.

6�5 - 4

SITE UNITS

White-veined wintergreenPyrola picta

Alaskan blueberryVaccinium alaskaense