Don Minore USDA ForestrySciences Laboratory 3200 Jeffersoo Vay Corvallis,Oregon 97331

VacciniumMembranaceum production Seven years After Trealmentto ReduceOverstory Tree Canopies,

Abslracl

oy:r(roryIrcrrmeflrr were appl:ed rn a berrl.field near Mounr Hood. Oregon, tha. w.rc shadcd Jl\e b'q iu(rirercr (,v.,,1,-.t.an.!.pk,n. l:_f:-1'l:l ,,1,!., he-rvprndur.i, n "as high,s, $h(-e,,rD Incrsronsfirl ! ) redlcedthe oversrorycanopy without disturbinE- r,accinint shrt$s In rrc undcr(or!v odJ'r.n wrsrowcr wh(rr Mrh nrcr.r. anJundqnr^rr urrc divurhJ h} cLr(tinAand burning or whcrrrh< ovcr.rory (rnopy wrs n"r r.du.eJ.

Introduction

Big (Vaccilittttt nettbranaceam Dougl. ex. Hook.) bearspalatable berries that are exrensivelyharvested by berry pickers 'Vashington. in the CascadeRange of Oregon and Mosr of the berriesare producedin sparselyforested subalpine areas where q-ildfires created favorable eovironmental conditions. Berry prcxluctioo declines when open-glowo V. rnenbrataceunt shrubsbecome heavily shadedby closetlforest canopies, however, and densesubalpine forestshave seriouslyreduced huckleberty prcduction in sweral heavily-usedberryfields. In rhe absenceof wildfire. silvicultural rrearmerts to reduceor eliminate rhe foresrovelsrory ale necessaryif former levelsof berry production are ro he resrored. Five oversroryrrearmenrs were applied h 1974 to a berryfieldshaded by dense young conifer forest,ancl subsequenr berry production was comparedto determinewhiclr *ras most effecrive. Treatment resulrs after three years were published previously (Mioore et aL.1!l!). Sweo-yearresults are presented here.

Study Area

The study area was 11 km southwestof Mouot Hood in Oregon on a gently sloping pacific $estero aspecrar an elevationof 1463 m in the silver lir (Abiet an.abilh ) Forest Zone (Franklin and Dyrness197J). AbundaotV. nentbtanacetntshmbs that covered about 45 percenr of the area x,ere overtoppedby a conifer ovetstory of about 14,000 conifer treesper hectarethat had an averagecanopy density of about 55 petcenr. Lodge_ pole (.Pituu .ontort,JDar{,|. ex l,oud_) nas the dominaot speciesin this.rrr"r.tory; but Douglas-fir t.PreutJot!/./gdnentie.rii (Mirb.1 Franco) , noble fi ( Ab;er prccera Rehder),sulnipioe fir A. ldsiocarya(Hook.) NLrtt.),grand fir (1. gtandb (I)otgl. ex D. Doo) Lindl.), mountain hemlock ('1'ttrgt ntettensiatta(Bong.) Carr.), western hemlock (7. hetetophllh (Raf.) Sarg.), \r(estero *,hite pite pitat z)toltricoLlDongl.

'This paper reports resr;rch invoiving an herbicide. lt does not c.ntain rcccrmmendationsfor its ure nur .lJ(s r rmplv rhrr rhe use(di\Lu\)cd I,cre havc hen rcgi,r,rer. A l,,rFr..l,, mu.r L,e rcgistercJhr approprrrE srateand/"r reJcraJagtn. rr. \.for. ,h.! ,rn h€ L,eJ.

208 Northwest Science,Voi. 58, No. 3, 1984 ex. D. Drn), Engiernannspruce (Plcea engelnaxnii Parry ex Engelm.),and Western re,Jceclar (Thtja pl;cara Donn.) were alm presenr above dte Vdccinitn . Bear- gtass(Xerofhlllutlr lrrrlri (Pursh) Nutt.) $as dominaot below the shrubs,but the herb stratum $xs also chuacterizedby dwarf brrmble (Rtbat l,riococcat Gtay), pearly everlasting(Anapholit tnarg,iritacca(I-.) B. & H.), and coiledpedicularis (Peclirularit contartaBer..h.) . The soil x'as coatse-textuled,shallo$, rocky, arld lorv in nurrieols.

Methods The study consistedof a completely rafldom experimeotaldesign, with five treatments replicatedfoLrr times (Tablc 1). Square0.14 ]recrateplots surrouodedby 3 m buffer srrips were arranged in a 4 x 5 plot grid. In the first treatment, all trees were cut on four randomly seleced plots in 1971. and rhe resuftioll slashrvas broadcasr-burned in late August 197,1.The slashfjre did oot consumethe blackenedVaccittirtn shoots, hur ir severelydi'curbed ,rll underqrnry vegec,rtion. A one-to'onemixture of 2,4-D amine and water was applied to stem incisions (frills) cut arouod the circumferelce of every tree larger thao 5-cm d.b.h. on four other plots in early Julv 1974.s'hen the lasr lemnanrsof a heavy\r'inter soow pack n'ere melting ancl Vaccittitott shrubs\!ere just beginning to produce leaves. The frills were spaced3.lt cm apalt. About 50 percent of the 14,000 trees./hectarewere large eoough to treat. The overstory\\'as severely distLrrbed, but the ufldelstorywas undisturbedin this secondtreatment. On a third seriesof plots. all vegerarionbelos' a height of 3 m was sprayedwith a low volatile ester of 2l-D in late Juiy 197/t to dry the vegetation for subsequentburniog. Burning rvasuosuccessful, however, aod this becamea 2l-D sprayrreatment that slightly disturbed the overstoryaod moderarelydisturbed the understory. Cooperatiogpatholo- gists iooculareclthe fourth seriesof plors vith Phellinat u,eirii (Mttrr.1 Gilbertsoo at this rime by placing P. ueirii cuhutes in contact with tire rcxrts of 25 well-spaceC trees on each plor. Little or ro overstory clisturbaocerxcurrecl oo the PhelLitu plots. The four control plots \\'ere nor distr.rrbedin any way. Beginning in 1975, berry pro-

T,AIILE 1, Trermenls and th.ir effe.is on ot!rsl.,rl and underst('r! !.seralion.

i1,.1I) irill :,;-crn DBH kill.d j.,1 D sprrt Foliage beloN il m kille.l Folhsc killcd Fhellt'trs ly.hii ih(xruhtion

tluctionwas sampled every orher yeal on everytrearment by pickingand weighing all the berrieson 16 systerraticallyspacecl .004-ha subplots on eachof rhe 2O plots. Vacciniun ntenbtanacetntberries ripened irregularlyon individual shrubs,and ripenessvaried among treatmenrs,so pickeclrveights \r'ere convetred to tipe *.eights:

LPicked rveighr) (Averagel-eighc of a ripe berry) { A\e-dte\\ei!l)r .,f,L pirke,l I'erry r

The ripe rveightsrvere subjecteclto anelysesof variance. Vhere significant differ"

Vaccinium MembraoaceumBerry Production 209 eocesamong tfearmenrsoccurred, Scheffe' (1959) multiple comparisontests were used to compale iodividual treatmenr means. Sample yearswele not comparedstatistically.

Re$ultsand Discussion Meteorological iofl:elces are very important in derermining aooual huckleberry pro- duction (Minore a[d Dubrasich 1978), and the weather was more favorable for berry productionin 1979than it was in 1981 (Fig. 1). Nevertheless,the 2,4-D frill treatment

-24Dj9+--.'-.. r _ o v ..^tJU .;c o o o 100 o o o o50 o o ,z".4;.->

production Figure 1. '$?eatherArerage berry trends during the 7 years after treatments were applied. was unfavorable for berry production in 1981. Tbe 19t5 and 1977 data are from Midore, Smart and Dubrasich (1979). produced more berries than orher treacmentsin both years (Table 2). Indeed, the superiority of 2,4-D frilling becamemote evident eachyear. Scheffe'tests indicate rhat 2,4-D ftrll was sigoificaotly better than the averageof all orher ffeatments,but oot significaotly different than aoy siogle rrearmentar P < 0.05 in 1979. lt 1981, berry

2r0 production of rhe 2,4-D frill treatment was significantly higher (P ( 0.05) than att orher treatmentsi the 2,4-D frill treatment was significantly higher than both Phelliwr and controltreatments at P { 0.01. The increasein berry production on the 2.4-D frill plots occurredwhen treated oversrorytrees died; most of the oversroryshade was eliminated without disturbing the understoryVaccittiuttt shrubs. Sirniiar resultsprobably couid be obtainedby girdling the oversrorytlees. After eirher rrealment,the dead trees remain standing for a long time. Only a few fell over during the seven years after 2,4-D rearment, and rhey have nor limitecl accessor createdsafery hazards. The ovetstory rrees rrearedin this sudy were shotr,ho$'ever, q'ith diametersof lessthan 16 cm (14 io.). Leavinglarge deadtrees on the stump would probably be hazardous.

T.lIlLIl !. Iverage berry !.or1uclio., by lreaiment and ycar.1

l uTtj 1!S1!

_-- Ks/ba _

2,1-D lrill !00.1

i6,?

2,1-D spray ;1.2

Phtlllntrs inoculation ! 9.2

108.0

:Each ayeraEe is based r)n 1rer)li.rrtes, Nith 16 subplol samDles per repli.arf. Sch,iife t.sls shox-ed ihc Dr.du.lion on 2,1 D frill tlols to be ,"isnilicrnilr higher (1, < 0.0;) than that ol all olher lr.almenls tr lhe lrill vs. olhers c.rmNrison, Lur dilferen.es amons individual rreatmenis were nor sialislicall! significanl. 'Arerascs nirhnr the brackel were nol signifi.rnll! dllfercnt at I, < 0.05 lrhen conrDared Niih Scheffe' resis. Those follo$'ed by lhe samc leler Fcrc not sienificanriy difiereni xl 1- < 0.r)1.

None of the overstorydied as a resulcol Phellinusueitii inoculati.or's,aod the Phel litu plots were iodistinguishablefrom untreated control plots seven yeals after treat- meor. Inocularion failure or a proioflged delay in the expressioflof diseasesymptoms may be tesponsible. The 2,4-D spraytreatment, originally intended to facilitate overstoryremoval rhrough subsequentburning, failed to affect overstory clensitysignificantly when the burniog faile<1.Vacciniau shrubswere normal in appearaocefive yearsafter being damagedby 2,4-D. Sevenyears after trearment,their berty producrionwas similar to that of other Vaccinitn. shrabsshaded by a denseoverstory. Vacciniant shoots were kilied by fire on the cut and burn plots in i974. Although they resproutedvigorously, the Vaccininn shrubshld not complerelyrecovered from this disturbanceafter sevenyears. The failure of fire to improve Vaccinitn rlrcnbra acetn berry productioo in seven yearsis surprising. for rnosr huckleberry fields seem to have become establisheda{ter wildfires, and periodic fires probably eliminated the forest oversrories rhar shaded huckleberry shrubs in the pasr. Huckieberry recovery from fire (Miller 1971, 1918) varies both *'ith fire intensiry, fuel condition, soil moisture, butning season,and Zac- ciniatn species,however. Postburn recoveryof V. glob arc cao be exceedinglyslow in Vestern Montana (Stickney1981).

Vaccinium MembranaceumBerrv Productioo 211 Past increasesit Vaccinir'ttt trcmbranacerm berry production associaredwith the burning of overstorytrees and huckleberryshrubs in the CascadeRange must have been delayed unril long aftet the fires. Reestablishmeotof overstoriesalso occurred long after the fires when uncontrolledfildfires swept over large areas,howeve!; and the delay probably was not particularly important when burns of all ageswere readily available ro rhe huckleberly pickers of former yeers. The delay may be important norv. If the results obcaioedon the srudy site are applicableelsewhere io the Pacific silver fir zone, rhe eljminarion of forest overstoriesby girdling or herbicide-frill treatments that do not disturb the Vdcc;ni rt uriderstoriesmay be chemost feasibleway to increasehuckle- berry production rapidly in heaviiy used berry fields tecenlly overgrown by subalpioe foresr.

LiteralureCiled

Franklin, Jerry F. and C. T. Dyrness- 1971. Natural vegetation of Oregon and \Tashington. USDA For. Serv. Gen. Tech. Report PN\fl'8. Pac. No.thwesr For. and Rangc Exp. Stn., Poitland, Ores. Nfiller, Me[nie. 1977. Response of bluc huckleberry to prescribed fircs in westero Mootana larch' fir {orest. U.S.D.A. For. Serv. Rcs- Papaer INT-188. lnterm. For. and Rangc Exp. Srn., osden, . -. 1978. Effect of growing season on sprouting of blue huckleberry. USDA For. sc.v. Res. Nore lNT.i I0. lntcrm. For and Rrnsc trp. Srn..Ogden, t tah Minore, Don and Michaei L Dubrasich. lrr-8. Big huckt(bcrr1 abuodancc.rs relatcd to environ ment aod associated vegetatioo near Mount Adams, \Vashington, USDA For. Serv. Res Note PN\V-122. Pac. Norrhwest Fot- nnd Range lxp. Stn., Ponland, Oreg. -. Minore, Don, Alan !9. Smart, aod l{ichael E. Dubrasich. 1979. Huckleberry ecology aod managcment research in thc . USDA For. Scrv. Geo. Tech. Report PN\{-91. Pac. Northwest For. and Rangc Exp. Sto., Portland, Oreg. Schcff€, H. 1959- The Analysis of Variance. Wiley, New York. Stickney, Petcr F. 1981. Veaet?tive recovery and development. 1z Ciearcutting and fire in the larch/Douglas-fir forests of westcrn Montana-a muLt;f.c.'tcd rcscarch summary (N.V. DeByle, ed.). USDA For. Serv. Gcn Tcch. Repon INT-99. P. ll-40 Inrerm ror' aod Range Exp. Stn., PorrLand, Orea.

ReceitecltrIatclt 7, 1983 Acceptedfor publicatiott Jute 23. 1983

212 Minore