53

Abstract

This extension note describes someof the effects of timber harvestingon the soils at the Sicamous CreekSilvicultural Systems Project studysite for the -year period since har-vesting. The study site is located inthe zone near Sicamous, B.C.Five harvesting treatments wereapplied: no harvesting, single-treeselection, .-, -, and -ha clearcuts.A variety of studies investigated theeffects of opening size and distancefrom the edge of the cut area on soilnitrogen dynamics, nutrient cycling,soil food webs, ectomycorrhizae, andfine roots. Generalizations regardingshort-term effects on the below-ground organisms and processes aredifficult. A complete absence ofsporocarp fruiting, increased rates ofnitrogen mineralization and increasednutrient leaching losses were notedin the first growing season after har-vest. Decreased ectomycorrhizaldiversity and fine-root biomass weremeasured after one growing season.Shifts in community structureoccurred for micro-arthropods andbacteria while no discernible impactwas detected for decomposition ratesand total collembola numbers. Allthese changes persisted for up to years after treatment, althoughnutrient leaching peaked after years.

The major influence of the forestedge into the opening occurredwithin approximately one-half of thetree canopy height of the uncut for-est. Cutting practices that create arange of opening sizes would bestmaintain the widest variety of soilbiological diversity and functions.

Introduction

Little information is available onmany aspects of the ecology ofhigh-elevation Engelmann Spruce–Subalpine Fir () forests, andeven less on below-ground organ-isms and processes in these ecosys-tems. To better understand theecology of these forests and theirresponse to timber harvesting, theSicamous Creek Silvicultural SystemsProject was initiated in the southernInterior of British Columbia. Thespecific objectives of the soil ecologycomponent of this project were togain an understanding of the prop-erties and processes affecting soilproductivity and the effects ofharvesting disturbance on thoseprocesses. Information gained fromthese studies will enable these high-elevation forests to be managed in amanner that sustains both soil andforest productivity.

The activities of soil-dwellingorganisms are directly related to site

The Soil Ecosystem of an Forest andits Response to a Range of HarvestingDisturbances

A

Ministry contact:Graeme HopeKamloops Forest RegionB.C. Ministry of Forests515 Columbia StKamloops, BC V2C 2T7

Extension Note

Ministry of Forests Research Program

productivity. For example, bacteriaand decomposer fungi produce theenzymes necessary to decomposeorganic matter and release inorganicforms of nutrients. Nematodes andmicro-arthropods feed on bacteriaand fungi and release excess miner-alized nitrogen into the soil solution.Ectomycorrhizal fungi take up thesenutrients and transfer them to theirplant hosts. Many of these organ-isms have never been investigatedin forests and, therefore, evenbaseline information documentingspecies presence is lacking.

This extension note summarizes thefirst years of results pertaining tothe effects of timber harvesting on thesoils at the Sicamous Creek study site.

Study Site

The Sicamous Creek SilviculturalSystems Project is situated in theHunter Range, southeast of the townof Sicamous in the southern Interiorof British Columbia. The study site islocated in the wet cold (wc)biogeoclimatic variant, and ranges inelevation from to m.

The dominant tree species aresubalpine fir (Abies lasiocarpa) andEngelmann spruce (Picea engelman-nii); these species range in age from– years. Subalpine fir consti-tutes % of the canopy species. Thesite series on zonal sites is the sub-alpine fir–azalea–oak fern unit(Lloyd et al. ). Soils on mesicsites are classified as Orthic Humo-Ferric Podzols with hygric areas clas-sified as Gleyed Sombric Brunisolsand Orthic Gleysols. Forest floorsrange in thickness from to cmand contain approximately –%decayed wood. Humus forms arepredominantly Hemimors.

Treatments

The site was divided into three ele-vation blocks, and five main treat-ments were applied to each block:no harvesting, single-tree selection,.-, -, and -ha clearcuts (Figure). Each treatment unit is approxi-mately ha in size. The site washarvested during the winter of–. Approximately % ofthe total timber volume was

Sicamous Creek study site viewed from the NE (photo by Alan Vyse).

Summary of soil ecology studies at Sicamous Creek

Sampling Sampling ParametersStudy method locations measured Reference

Soil chemistry and Soil collection, Plots in all Soil chemistry, Hope and

nitrogen dynamics field incubation of treatments; transects N mineralization; Prescott 2000

soil and litter bags in one 10-ha block litter decomposition

Fine roots Soil cores Plots in control, Fine root biomass Welke and

0.1-, and 1.0-treatments; and nutrient Hunt 1999

transects in one content; fine root

10-ha block decomposition

Ectomycorrhizae Soil cores, Plots in control, Ectomycorrhizal Hagerman et al.

bioassay seedlings, 0.1-, 1.0-, and 10-ha diversity and 1999a, 1999b,

nursery seedlings treatments, plus transects community structure Jones et al. 2000

in the three 10 ha- and

in three 1.0-ha openings.

Hypogeous Collection of below- Control, 0.1-, Biomass Jones et al. 2000

Sporocarps ground sporocarps 1.0-, and 10-ha

in 4 m2 plots treatments

Soil food-webs Soil collection from Control, 1.0-, Total soil bacteria, Hope and

circular plots 10 m and 10-ha fungi and nematodes; Johnson 1999

in diameter treatments N mineralization

and denitrification

Soil micro-arthropods Soil cores Centre of control, Mites and collembola; Nadel 1999

0.1-, 1.0- and 10-ha abundance and

treatments, plus transect diversity

in one 10-ha block

Nutrient dynamics Analysis of soil Control, 10-ha treat- Nutrient inputs Feller 1999

water samples ments, plus selection and outputs in

and plants cut for N-fixation solution, N-fixation

removed in each of the four treat-ments. All timber harvesting treat-ment areas were site prepared by acombination of mounding andscreefing. Most soil ecology studiestook place in undisturbed groundwithin the site-prepared areas.

Sampling

Sampling techniques were specific tothe property or process being mea-sured, and details can be found byreferring to the original studies(Table ). Most studies investigatedthe effect of opening size and dis-tance from the edge of the cut area.

Soil Ecology of theUndisturbed Forest

Chemistry

The soils at the Sicamous site exhibitthe characteristic acidic pH found inother soils. The amounts ofnitrogen and sulphur were lower inthe forest floor than in the surfacemineral soil because the forest floorat Sicamous is relatively thin (Table). However, the total nutrient capi-tal of these elements, together withthe content of available phosphorusand cations (data not shown) andthe carbon to nitrogen (C:N) ratio

of both forest floor and mineral soil,indicate that these soils are as fertileas those from lower-elevation sites inthe Kamloops Forest Region. Miner-alizable nitrogen and C:N ratio indi-cate that the forest floor had greatermicrobial nitrogen (the most avail-able N) and higher rates of nitrogenturnover on a per gram basis thandid the mineral soil. Nitrate com-prised –% (depending on the sea-son) of the extractable nitrogen poolin forest floors, and between –%in the surface mineral soil.

Fine Roots and Litter Inputs

In western temperate forests, annualfine root turnover ranges from %to % of the standing crop and con-tributes an estimated – times moreorganic matter to the soil than leafand branch litter combined (Fogel andHunt ). Fine roots (< mm diam-eter) were an important contributorto organic matter in the undisturbedforest at Sicamous Creek, with annualmaximum standing crops over yearsranging from to kg/ha. Totalannual input from above-groundlitterfall measured over years was kg/ha. This litter fall was com-prised of needles (.%), leaves(.%), fine woody debris (.%),and coarse woody debris (.%).

Ectomycorrhizal Fungi

Ectomycorrhizal fungi play a vital

role in the forest soil ecosystem,forming a symbiotic association withplant roots and contributing to thesoil food-web as a source of foodfor invertebrates and small mam-mals. The fruiting bodies of some ofthese fungi form below-ground, arecalled hypogeous sporocarps (ortruffles), and are a common foodsource for small mammals. Speciesrichness of the hypogeous sporo-carps sampled from the uncut forestranged from – species per m2

plot. While over taxa weredescribed in years of study, threespecies—Hydnotria variiformis, Hys-terangium coriaceum, and Thaxtero-gaster pingue—were typically themost abundant. Spatial variation infungal biomass was marked, reflect-ing the highly clumped distributionof many species.

The ectomycorrhizal communityin the uncut forest was representedby a diverse array of fungal speciescolonizing the fine roots of trees.Numerous rare types and a fewdominant types characterize thecommunity structure. Thirty-ninetypes were described during the years of soil-core sampling.

Soil Food-Webs

Four essential components of thesoil food-web were investigated:bacteria and fungi, which bothdecompose organic matter, andnematodes and micro-arthropods,

Chemical properties of the undisturbed forest soil at Sicamous Creek

Soil chemical property

Sample Total C Total N Total S C:N Mineralizable N pH

Concentration (g/kg)

Forest floor 432 15.1 1.5 28.7 5.8 4.3

Mineral soil 48.0 2.4 0.2 19.8 0.5 3.9

Content (kg/ha)

Forest floor 16455 610 62 23

Mineral soil 55665 2520 259 50

which are the most abundant con-sumers of bacteria and fungi. Ofthese four groups, fungi were by farthe largest contributors to biomassfollowed by bacteria, nematodes, andmicro-arthropods.

Seven collembola families and

mite families were detected. A num-ber of collembola species identified inthis study have not previously beenreported from British Columbia.These included Ceratophysella glancer,Pratanurida tananensisg, and Folsomia inoculata, as well as several speciesnew to science. Micro-arthropoddensities ( mites and

collembola per square metre in theuncut forest) were comparable tothose reported in other studies. Themost abundant mites were the orib-atid mites, which are typical of Morhumus layers. Like the collembola,these mites prefer the moist condi-tions that were generally found inboth the openings and forest.

Nutrient Cycling

Annual inputs and outputs by solu-tion (precipitation and mineral soilleachate, respectively) in the uncutforest were relatively low, with inputsof nitrogen, phosphorus potassium,

sulphur, magnesium, and calciumeach averaging less than kg/haannually and outputs averaging lessthan kg/ha annually for all nutrientsexcept potassium (. kg/ha per year)and calcium ( kg/ha per year). Totalnitrogen inputs were closely balanced by total outputs (. kg/ha per yearand . kg/ha per year, respectively).This indicates that no net nitrogeninput into the forests occurs via thesolution pathway. Nitrogen fixationinputs measured for a chrono-sequence of sites (includingSicamous) from zero to greater than years were relatively low (< .kg/ha per year) compared to nitrogendemands by the forest vegetation.

Short-term Responses toDisturbance: Opening Size

Fine Roots

Three and four years after harvest( and ), both active andtotal fine root biomass weresignificantly higher in the uncutforest compared with the .-ha and.-ha openings (Figure ). For thespring sampling in the fifth year afterharvest, fine root biomass in theuncut controls was actually lower

Spring 1997

Total Inactive Active

Control0.1 ha1.0 ha

2000

1600

1200

800

400

0

Spring 1998

Total Inactive Active

Control0.1 ha1.0 ha

2000

1600

1200

800

400

0

Fine

roo

t bi

omas

s (k

g/ha

)

Effects of opening size on fine root biomass during spring sampling in 1997 and 1998 (bars arestandard errors of the means).

Fine root type Fine root type

than either of the openings, probablybecause of the high, late-melting snow-pack in that year (data not shown).

Ectomycorrhizal Fungi

Logging had a dramatic effect on theincidence of below ground ectomy-corrhizal sporocarps. Throughout the years of post-harvest sampling, nosporocarps were found in any of theopenings (. ha, . ha, and ha).For ectomycorrhizal roots, no differ-ences existed in diversity (expressedas number of ectomycorrhizal types)during the first growing season afterharvesting. In subsequent yearshowever, harvesting had a significantnegative effect. The persistence offine roots and ectomycorrhizaldiversity declined significantly in theopenings away from the forestedge (Figure ). This same patternof decline was observed for thediversity of fungi colonizing

non-mycorrhizal field bioassay seed-lings (Figure ).

Nursery-grown seedlings plantedin the openings did not exhibit thepattern of reduced inoculum levels,which was detected in the non-mycorrhizal seedlings. This nurserystock was extensively colonized bymycorrhizal fungi before planting,and these fungi evidently were effec-tive competitors for new coloniza-tion sites along extending roots inthe field. Because of this, the overalldiversity of ectomycorrhizae on thenursery-grown seedlings was lowerthan on the young non-mycorrhizalseedlings.

Food Webs

With the exception of bacteria, allcomponents of the soil food-webshowed a harvest-related shift, –

years after harvest (Table ). Particu-larly evident was the decline in fungal

1996 1997

a

ab

b

b bb

a

b

bb

b

b

15

10

5

0

8

6

4

2

0

-40 2 16 25 50 165 -40 2 16 25 50 165

No.

of e

ctom

ycor

rhiz

al t

ypes

Distance (m) into the opening

Richness of ectomycorrhizae with increasing distance from the block edge (with negative values rep-resenting distance into the forest), in soil cores sampled two and three growing seasons after log-ging. Values with same letter are not significantly different at P<0.05. Error bars represent one stan-dard error of the mean.

biomass (active + inactive) in forestfloor samples from the openings. Anincrease in bacterial and fungal bio-mass is often observed after harvestbecause of the warmer soils andincreased moisture. The results from

Sicamous Creek do not support thismodel; in fact, fungal biomass wasreduced and bacterial biomassremained unchanged. Although theoverall numbers of bacteria wereunchanged, a community shift was

0

1

2

3

4

5

6

2 16 25 50 165

0

1

2

3

4

5

6

2 16 25 50 165

Distance (m) into the cut-blocks

1996 1997

No.

of e

ctom

ycor

rhiz

al t

ypes

Number of types of ectomycorrhizae encountered on seedling roots grown at Sicamous Creek for 13weeks, two and three growing seasons after logging, with increasing distance from the block edge.Error bars represent one standard error of the mean.

Biomass for the food-web variables measured at Sicamous Creek two throughfour years following logging at plots located in the undisturbed forest, and thecentre of the 1.0- and 10-ha openings

1-ha 10-haFood-web variable Year Forest centre centre

Bacteria (mg/g dry soil) 1996 63.40 a 64.30 a 67.34 a1997 199.06 a 286.37 a 242.03 a1998 256.94 a 404.17 a 493.12 a

Fungi (active + inactive) 1996 3972.67 a 2866.21 a 3012.67 a(mg/g dry soil) 1997 2803.48 a 1916.41 b 2018.94 a

1998 2098.51 a 638.84 bc 1108.38 b

Nematodes (per g dry soil) 1996 15.59 a 30.26 a 15.26 a1997 16.16 a 14.23 a 11.00 a1998 67.99 a 24.7 b 20.57 b

Micro-arthropods (per g dry soil) 1996 6.23 a 1.66 b1998 8.78 a 4.06 b 4.36 b

Within rows values followed by different letters are significantly different at p < ..

detected, with denitrifying bacteriamore common in the openings.

The effect of harvesting on micro-arthropod densities varied dependingon the sampling method and thetime of year. Biomass estimatesgenerated from the food-web studyrevealed a decline in these fauna inthe -ha openings relative to theuncut forest. In the finer-scalesoil fauna study, no effect of harvest-ing (any opening size) on micro-arthropod numbers was detected inforest floor samples. This discrep-ancy may be related to the timing ofsampling. The food-web samplingwas undertaken in the late summerwhen soil conditions were warmerand drier than in the late fall whenthe soil faunal samples were collected.

Although canopy removal had noclear influence on micro-arthropodnumbers during the first yearsafter harvest, differences were detectedin the third year. By this time, thehighest numbers of mites in forestfloor samples were observed in the-ha openings. The major effect ofcanopy removal was in mineral soilsamples, where the number of mitesin all openings (Table ) and theabundance of two of the majorfamilies of collembola, were signifi-

cantly reduced. However, total num-bers of collembola were unaffectedby canopy removal (all opening

sizes) in both forest floor and min-eral soil samples (Table ).

Nutrient Cycling

Forest harvesting increased leachinglosses of nutrients, particularlynitrogen (primarily nitrate) andpotassium. Accumulated -year post-harvest losses attributed to leachingwere and kg/ha, respectively.Annual nitrogen losses representapproximately .% of the totalnitrogen content of the forest floorand surface mineral soil (Table ).Harvesting-induced losses of magne-sium, calcium, and sulphur rangedfrom to kg/ha per years,while phosphorus losses were lessthan . kg/ha per years. Leachinglosses peaked between the secondand third year after harvest, anddeclined substantially in the fourthyear (Table ).

Nitrogen Dynamics

The concentrations of mineral nitro-gen (ammonium and nitrate) mea-sured in incubated soil samples(forest floor + mineral soil) weresignificantly greater in the .-, .-,and -ha openings than in the con-trol and selection cut in the yearsof study ending in . This indi-cates that nitrogen mineralization

Mean density of soil mites and collembola (individuals/m2) collected fromthe forest floor and mineral soil at the end of three growing seasons afterharvest (1997)

Uncut control 0.1 ha 1.0 ha 10.0 ha

Forest floorTotal 169 390 a 126 120 a 129 160 a 174 440 aMites 105 410 ab 70 790 b 75 820 ab 116 910 aCollembola 63 980 a 55 330 a 53 340 a 57 530 a

Mineral SoilTotal 101 430 a 53 060 b 35 310 b 49 900 bMites 72 300 a 33 060 b 20 330 b 33 850 bCollembola 29 130 a 20 000 a 14 970 a 16 050 a

Means within a row followed by the same letter are not significantly different (p < .).

rates were higher at these locations(Figure ). Additionally, the propor-tion of nitrate relative to ammoniumincreased over time in the larger(≥ . ha) openings.

The increased concentrations ofmineral nitrogen commonlyobserved after clearcutting are oftenexplained by the moister andwarmer conditions in the openings,which leads to faster decompositionand mineralization, and higher con-centrations of nitrate (see Prescott etal. for a full discussion of thisissue). However, at Sicamous Creek,increases in nitrogen were not

accompanied by faster decomposi-tion rates. In fact, no opening sizeeffect was observed in the decom-position rates of any of the fivesubstrates (spruce/fir needles, spruce/fir roots, forest floor material, aspenleaves, lodgepole pine needles) overthe -year period since harvesting.

Short-term Responses toDisturbance: Distance fromthe Edge

Ectomycorrhizal diversity assessedfrom soil cores and bioassayseedlings declined with increasing

Estimated annual leaching losses (kg/ha) measured in the 10-ha openings 1–4 years after harvesting

Nutrient loss (kg/ha)

Total Organic Nitrate Ammonium TotalYear Na,b Na Na Na Pa Ka Mga Caa SO4–Sa

1994/1995 3.4 1.7 1.6 0.1 0.0 10.2 1.1 3.5 1.71995/1996 14.9 2.9 11.5 0.5 0.1 18.8 2.7 12.0 4.21996/1997 19.1 2.5 16.4 0.2 0.1 19.0 5.5 1.8 4.81997/1998 8.4 1.1 7.3 0.0 0.1 1.4 2.0 3.8 1.54-Year Total 45.8 8.2 36.8 0.8 0.3 49.4 11.3 21.1 12.2

a nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), and sulphate–sulphur (SO4–S)b total N is the sum of organic, nitrate, and ammonium N

A. Forest floor

Year

Min

eral

nitr

ogen

(m

g/k

g)

AmmoniumNitrate

B. Mineral soil

Year

MIn

eral

nitr

ogen

(m

g/kg

)

1996 1997 1998 1999

Ammonium Nitrate

1996 1997 1998 1999

400

350

300

250

200

150

100

50

0

40

35

30

25

20

15

10

5

0

C

S

0.1 10

10

101.0

S

S

SC

C

C

1.0

0.1

1.00.1

C

C

10

0.1

10

1.0

C

S

S

101.00.1

0.11.0

10

0.11.0

0.11.0

10

S

C

S

Concentrations of ammonium-N and nitrate-N in forest floor and mineral soil samples after a 6-weekfield incubation from July to mid-August, over a 4-year period from 1996–1999. Treatment symbolsmarked on each bar are: C, control; S, selection cut; and 0.1-, 1.0-, and 10-ha openings.

distance from the forest edge intothe openings. Diversity becamesignificantly lower between and m from the forest edge (Figures and ). This was observed and years post-harvest and may beexplained by the maintenance ofactive ectomycorrhizae associatedwith trees whose roots extend intothe openings from the adjacent for-est. No differences were observed inthe diversity indices at correspond-ing distances from the edge of dif-ferent opening sizes (as detected bysoil cores and bioassay seedlings) –

years after logging. The diversity ofectomycorrhizae associated withnursery-grown seedlings was notaffected by distance from the edge.Fine root biomass also declined withdistance from the edge in the -haopenings (Figure ). Samples takenin the fall of and hadsignificantly less fine root biomass(active + inactive) at the centre ofthe opening compared with the

edges and within the forest. No dif-ferences in micro-arthropod num-bers were detected with distance fromthe edge up to years after harvest.However, significantly fewer miteswere evident in samples taken fromthe south edge of the -ha openingas compared with the centre andnorth edge regions. There was atrend of increased nitrogen mineral-ization approaching the north edgeof the -ha openings relative to thecentre and south edges, and yearsafter harvest.

Summary and Implicationsfor Forest Management

• The below-ground organisms andprocesses measured at SicamousCreek responded in different waysto the various treatments duringthe first years after harvest,making generalizations difficult.Some responded immediately toharvesting (complete absence of

Edge and distance from edge (m)

Inactive roots

Active roots

2400

2000

1600

1200

800

400

0S - 40 S + 2 S + 25 165 N + 25 N + 2 N - 40

Inactive and active fine root biomass along transects in 10-ha plotsin the fall of 1997 (bars are standard errors of the mean). Negativedistances from the edge represent points into the forest, positivedistances represent points into the opening.

Fine

roo

t bi

omas

s (k

g/ha

)

sporocarp fruiting, increased ratesof nitrogen mineralization andincreased nutrient leaching losses,while others responded after onegrowing season (decreased ecto-mycorrhizal persistence anddiversity, and fine root biomass).Shifts in community structureoccurred for micro-arthropodsand bacteria, while no discernibleimpact was detected for decom-position rates and total collem-bola numbers.

• Nutrient leaching losses peakedbetween the second and thirdyears after harvest. All otherresponses to the treatments con-tinued until the end of the -yearperiod of study.

• The centres of .-ha and -haopenings were very similar in soilbiological activity. The majorinfluence of the forest edgeoccurred within approximatelyone-half of the tree canopy heightof the uncut forest.

• Two factors important for seed-ling establishment and growth,nitrogen mineralization andestablishment of ectomycorrhizae(albeit from nursery fungi presentat out-planting) were wellestablished in openings largerthan . ha.

• Distance from the edge had agreater influence on the amountand diversity of active ectomycor-rhizal inoculum than did openingsize. Therefore, openings that havea high perimeter-to-area ratio orthose with patches of trees through-out, will maintain the highestamounts and diversity of availableectomycorrhizal inoculum.

• The main effect of timber har-vesting on micro-arthropods wasa shift in community composition.

At the family level, some micro-arthropod groups decreased inabundance while others increased.The significance of these shifts isunknown.

• Disturbing the forest by timberharvesting and then re-plantingcreates a different ecosystem: fineroot and litter inputs becomeminute, nitrogen mineralizationprocesses are altered, and thecommunity structure of soilorganisms changes. The implica-tions of the observed changes areunknown at this stage. However,there was no evidence to suggestthat soil biological processesceased in the new ecosystem.

• Because specific organisms areaffected differently by timber har-vesting disturbance, and becausewe are unsure of the significanceof observed changes, cutting prac-tices that create a range of open-ing sizes would best maintain thewidest variety of soil biologicaldiversity and functions.

Text by Shannon HagermanSoil Biology Consultant – Ackroyd RoadRichmond, BC

References

Feller, M. . Sicamous CreekSilvicultural Systems Project: Theresponse of Engelmann spruce–subalpine fir forest ecosystems tologging—The effects of harvestingon nutrient budgets. Unpublishedfinal report, #: -.Science Council of BC, Vancouver,B.C.

Fogel, R. and G. Hunt. . Fungaland arboreal biomass in a westernOregon Douglas-fir ecosystem: dis-tribution patterns and turnover.Can. J. For. Res.: –.

Hagerman, S.M., M. Jones, G.E.Bradfield, M. Gillespie, and D.M.Durall. a. Effects of clear-cutlogging on the persistence anddiversity of ectomycorrhizas at asubalpine forest. Can. J. For.Res.: –.

Hagerman, S.M., M.D. Jones, S.M.Sakakibara, and G.E. Bradfield.b. Ectomycorrhizal coloniza-tion of Picea engelmannii x glaucaseedlings planted across cut-blocksof different sizes. Can. J. For.Res.: –.

Hope, G. and C. Prescott. .Sicamous Creek SilviculturalSystems Project: Effect of silvicul-tural systems on soil productivity.Unpublished annual report,#: -/-, #:-. Science Council ofBC, Vancouver, B.C.

Hope, G. and K. Johnson. .Sicamous Creek SilviculturalSystems Project: Effect of silvicul-tural treatments on soil food weband nitrogen dynamics in study sites. Unpublished finalreport, #: -/-,#: -. ScienceCouncil of BC, Vancouver, B.C.

Jones, M., J. Alden, D. Durall, and S.Hagerman. . Sicamous CreekSilvicultural Systems Project: TheEffect of Cutblock Size on FungalDiversity at Sicamous Creek.Unpublished final report, #:-/-, #: -.Science Council of BC, Vancouver,B.C.

Lloyd, D., K. Angove, G. Hope, andC. Thompson. . A guide to site

identification and interpretationfor the Kamloops Forest Region.B.C. Min. For., Victoria, B.C. LandManagement Handbook No. .

Nadel, H. . Sicamous Creek Sil-vicultural Systems Project: Effectsof silvicultural practices on soilmicroarthropods in an forest.Unpublished final report, #:-/-, #: . Sci-ence Council of BC, Vancouver, B.C.

Prescott, C.E., L.L. Blevins, and C.L.Staley. . Effects of clear-cutting on decomposition rates oflitter and forest floor in forestsof British Columbia. Can J. For.Res. : –.

Welke, S. and G. Hunt. .Sicamous Creek Silvicultural Sys-tems Project: Effect of silviculturaltreatments on fine root biomass.Unpublished annual report,#: -/-. ScienceCouncil of BC, Vancouver, B.C.

Acknowledgements

Jan Addison, Dan Durall, MichaelFeller, Shannon Hagerman, GaryHunt, Kathleen Johnson, MelanieJones, Hannah Nadel, CindyPrescott, and Sylvia Welke all con-tributed to this extension note

This publication is part of the Sica-mous Creek Silvicultural SystemsProject. Sicamous Creek is an inter-disciplinary, inter-agency researchproject investigating many aspects ofmanaging high-elevation forests inthe southern Interior of BritishColumbia. Funding for the soil ecol-ogy research and extension projectwas provided by Forest Renewal BC.

The use of trade, firm, or corporation names in this publication is for the information

and convenience of the reader. Such use does not constitute an official endorsement or

approval by the Government of British Columbia of any product or service to the

exclusion of others that may also be suitable. This Extension Note should be regarded as

technical background only.