RESTORATIONOFTHE CALAVERASNORTHGROVE

CALAVERAS NORTH GROVE RESTORATION

TheCaliforniaDepartmentofParksandRecreationhasbegunamajorproject torestorethehealthoftheNorthGroveforest ecosystem – aprojectthat willtakeseveralyearstocomplete.FundingforthisprojecthasbeenprovidedbytheSierra NevadaConservancy,an agencyoftheStateofCalifornia.

Crews willbethinning theforest ofsmalland mediumsizedtrees,creatinga forestthat webelievewillreflect thespeciescompositionandstanddensityofanaturalecosystem.TheseactionsinturnwillreducetwomajorthreatscommontomanyforestsintheSierraNevada: fireandinsect attack.

WHYISTHEFORESTINNEEDOFRESTORATION? Prior tothe 1860s,the forestsof theSierraNevadaexisted ina naturalstate, withthevariousspeciesoftreescontrolledbytheprocessesofnature.Somespecies,suchasponderosapine,werefoundinopen,sunnystandsonridgetopsandsouthfacingslopes.Shadetolerantspecies,suchaswhitefir,wereconcentrated insomewhatdenserstandsonthecoolernorthfacingslopesandwithinthewell‐shadedgroveofmature giantsequoias.Theserelationshipsweremaintainedbyexposuretofrequent,lowintensity, unregulatedfires.

Scientistshavedeterminedthatfiresoccurred in thelandscapeabouteverytenyears‐sofrequently,infact,thatfuelsdidnot havemuchofachancetobuildup,andeachsubsequentfirewouldusuallybepatchyandoflowintensity.Suchfiresdidlittledamagetothelarge,old growthtreesthatdominatedtheforest,butdidmakelifedifficultfor youngtrees, fewofwhichcouldsurviveto maturity.Thismaysoundlikeabadthing,butlimitingthereproductionoftheforestwasessentialtokeepingit healthyand intact.

Whenhumansbeganactivelymanagingtheforestoneofthefirstthingsdonewastopreventtheseperiodic fires,whichwas thoughtatthetimetobeagoodthing.Treereproductionflourishedandtheforestbecamemoreand moredense,whileat the sametime thefuelsthat couldfeed afirebecame heavierand morecontinuousoverthelandscape.Threethingshappened,asaresult:

1) Thespecies thatdidwellinashadedforestwereverysuccessfulatcreatingnewtrees,whilethosewhoseseedlingsneededlotsofsunlightproducedfewerand feweroffspringas theforest becamedarker,and–inthecaseofponderosa pine– essentially stoppedreproducing.

2) Theincreaseddensity oftreeswas tryingtocompetein anecosystemthatdid notalsohavecorrespondingincreasein thevital

resourcesneeded forgrowth,especiallysoilmoisture.Thetreeswithdrewwaterfrom theground atagrowingratewhiletheaverage amountofwater(fromannualrainandsnowfall)remainedthesame. Asthis problemgrew,treesessentiallyexperiencedmanyartificiallyinduceddroughtyears.

3) Thelongperiodbetweenfires,coupledwiththeimmenselyincreasedamountoffuel,guaranteed thatfuture fireswouldbevery,very,destructive tothe trees,wildlife,andwatersheds.

WHAT ARE WE TRYING TO DO? Ecologistsfeelthatthe primevalforestsof the parkaveraged about60to80large,maturetrees peracre,withreproductionlimited tosmallpatchesscatteredthroughoutthestand.Today,wehavemanyparts oftheforest thathave 300to400 trees peracre,andsometimesmanymore!Reproductionisnowevenlydistributedthroughouttheforest,butmostlyconsistsofshadelovingspecies,especiallywhitefirand incensecedar evenunderneath themajesticponderosapines. Our goalsareto restore normaldensitiesand distributionsofallspecies, andtoallowfiretoplayitshistoricalroleintheforestecology.

WHAT ABOUT THE GIANT SEQUOIAS?

Fireplayedanimportantroleinthe ancientforest, anditwasacriticalfactor intheecologyofgiant sequoias;in theabsence offrequent fire,there hasbeena failureofthespeciesto reproduceand theold‐growthtreesthathavenaturally toppledanddiedhavenotbeenreplaced.The groveis nowdisappearing–very,veryslowly,ofcourse,butifleftunchecked,disappearancewillbetheultimateandtragicresult.

Thefrequentfires that naturallyoccurredinsequoiagrovesbefore man‐madesuppressioncausedthe massivereleaseofseedsfromthe canopyofthebigtrees –perhapsasmanyas200,000seedsPERTREE!Ifthisrainofseedsoccurredundersuitableconditionsitcouldresult inacarpetofseedlingsacrosstheforestfloorprovidinga suitablebank ofyoungtrees,someofwhichwouldsurvive tobecomesaplings,someofwhichwouldsurvive tobecomepolesizedtrees,untilfinallyoneeventually survivestoreplace the parenttree.

Wewillbeusingfireto burnmuchofthebiomass generatedbythisthinning project;whenwestartworkingwithinthegroveitself,we will strategicallyplacethefiresinsuchawaysoastostimulateseedrelease and(hopefully)successfulreproduction.

WHAT HAPPENS NEXT? Oncethestructureofthe foresthas beenrestored, weintendto maintain the workbyputtingfirebackintoitsnaturalrole.Deliberatelyignitedandcloselycontrolledsmallfireswillbesetwhenitcanbedonesafely.Hopefully,inyourfuturevisitstotheforest youwillseeahealthy,vibrant,andproductiveNorthGrove.