~ United States ~ Department Blue Oak Plant Communities of Southern of Agriculture Forest Service San Luis Obispo and Northern Santa Bar­ Pacific Southwest Research Station bara Counties, California General Technical Report PSW-GTR-139 Mark I. Borchert Nancy D.Cunha Patricia C. Kresse Marcee L. Lawrence Borchert. M:1rk I.: Cunha. N,mcy 0.: Km~,e. Patr1c1a C.: Lawrence. Marcec L. 1993. Blue oak plan! communilies or:.outhern San Luis Ob L<ipo and northern Santa Barbara Counties, California. Gen. Tech. Rep. PSW-GTR-139. Albany. CA: P:u:ilic Southwest Rcsc:arch Stution. Forest Service. U.S. Dcpurtment of Agriculture: 49 p. An ccologic:11clu,-sili.::uion '),,cm h:b Ileen developed for the Pacifil' Southwest Region of the Forest Service. As part of that c1a....,11ica1ion effort. blue oak rQ11('rrn., tlo11i;lusi1 / woodlands and forests ol ~out hem San Lub Ohi,po and northern Santa Barham Countie, in LO!> Padre!> Nationul Forest were cl:",ilicd imo i.\ plant communitic, using vegetation colkctcd from 208 plot:.. 0. 1 acre e:ach . Tim.'<.' di,tinct region, of vegetation were 1dentilicd 111 the ,tudy :1rea: Avcn:1lc,. Mirnndn Pinc Moun11,ln :ind Branch Mountnin. Communitie.., were dassilied ,eparntel) for plot, in each region. Each region ha, n woodland community thut occupies 11:u orgently slopmg bcnt·he..,.1oc,lopc~. and valley bo110111s. Thc,:c rnmmunitics possess a reltuivcly high proportion oflarge trcc, ( 2: I!( an. d.b.h.l 311d appcarro be heavily gnu cd. In s•ach region an extensive woodland or fore,t communit) covers modcr:uc , lope, with low ,olar in,ol:11io11 . These communities have in rnmmon .1 rclamely h,gh dcn,it) (> 1110 per acre) of ,nir,11· diameter lrs·cs (2-6 in. d.b.h.). Xcric communitks on moder.Ile ,lope, with high ,olar in,nlation ore prc:.cnt in each region. In gencr:tl. however. hlue oak i, poorly rcprc:.cntcd in xeric topogr:1phic >ell ing:, in the study arC:J. Two raro commun11ic-s oecupy , tc-ep \ltc, w1lh low ,nlar 1n,ola11on 111 the Mirundtt Pinc 1'vloun1:1in and Branch Moumain region,. fu1ch co111n11111i1y ha, l11gh ,pccac, richnc,,.,, und contuitL'­ :, di,,,n~' tiv.- '-Cr nr high e<H1Sl :,11<·y ,pcdes. Finally. upper dev:111011 "Vodl:md und torc~l communitie$ are prc,cn1 in Avenalc, und Bn111d1 Mountain 1cgi,11i-. where 1x,1h "'lume .md tree dcn,it) an.· high. Keys 10 the plant conm1uni11cs :arc included III un .1ppcnd1,-. Thc,c c:ommu11111c, will ,crve :1> a fr.unework for gathering productivity and munugc111cnt in(om1a1ion tor further refinement. f(l'lri;,,•al frrms. Q11;,rnr.,. Q,wrrn) tlm,gla,,·ii. vcgct:llt(ln cl:t"ilicarion. C:1lifom1a oal.,. blue oal. The Authors: Mark I. llorchert i, fore,, ccologi,t. Lo, Padre, Nati onal Forest. Goleta. California. ancy D. Cunha " o horam,1 livmg ,n Ara,cadero. California. Patricia C. Krossc i~ a ~oil ,t·1c11ti,1 and re.,oun·c ,pcc1nl" 1on the Tonga,, 'ln1,onal Forc,1. Kctchiktin. Alaska. Marcce L. Lawrence i, a hot:mi,t livinl,! an Fort Collin,. Colorado. Acknowledgments: We thank Ragan M. Callaway. Todd H. K.:clcr,Wolf. Barh.,rn H. Allcn-Diu7. Barburn t\ , Holzman. [llld Thoma~ M. Ryan for reviewing the manu,c:npt :md Roberta M B11r1yn<k1 for curcfully cdi11ng ii. Marwc L. Lawrcn~c a-:.,i,tcd in the idcntifie~tion of plunt, in the fiN yc:tr. Dc:an G. C.iprnlis :md Anuju K. Parikh identified plant,. and Lyn I::.. Moody da"1li.:d ,oil\ ,n the third season. Thomas M. France and Westley E. Shooi.. 111 greatly ,1'>1\tC'd In the complc:11011 ol th" prOJ<!Ct. Cm·a : Blue oak woodl:ands und open annu:,I gr:i,,land, in the Branch Mountain region. San Lui~ Obi~po County. C:1 liforn111. Publisher: Pacific Southwest Research Station Albany, California (Mailing address: P.O. Box 245. Berkeley. California 94701-0245 Telephone: 510-559-6300) February 1993 Blue Dak Platt Commllilies or SOUlhern san Luis Obispo - Norlhern Sada Ba'bara r.ounties, calilor­ lia Mark I. Borchert Nancy D. Cunha Patricia C. Kresse Marcee L. Lawrence Contents Introduction ............................................................................................................................................. I Study Area ................................................................................................................................................ I Topography .. ............. .......................... ..................................................... .......... .... ................... .... .... .... I Geology ............................................................................................................................................ .... 1 Climate ...................................................................................................................... ............... .... ........ 3 Distribution of Blue Oak ........... ........... .................... ...... .......................... .......... .................. ..... ............ 3 Methods .................................................................................................................................................... 4 Sa11 1µ li11g ............................ ................................................ .............................. ............... ...................... 4 Data Analysis ............ .......... ..................... ..... ..................................... ................................................... 4 Results and Discussion ............................................................................................................................. 5 Soils ............ .... ............... ..... ...... ..... ..... ........... .......... .......... ...... .... ................ .... ............... ............. .... ..... 5 Avenales Stand Classificati on ............ ........... ..................... .......... ..... ............... .............. ..... .... .............. 6 Avenales Plant Community Descriptions .......................... ...... .................... .......... .... .... ............ .. .......... 7 Blue Oak/Foxtail Grass-Johnny-Jump-Up .................................................... ........... ... ......... .... ..... .7 Blue Oak/Chile Lotus-Purple Needlegrass ...................................................... ................... .... .......... 8 Blue Oak/Wart Spurge-Golclenback Fem ..................... ........... .... ..... ................................................ 8 Blue Oak/Phlox-Leaved Bedstraw-Bajada Lu pine .. .................................... ......... .............. ............. .9 Miranda Pine Mountain Stand Classi lica1i on .................. .............................................. ...................... 18 Miranda Pine Mountain Plant Community Descriptions ..................................................................... 18 Blue Oak/White-stemmed Filaree-Foxtail Grass .. .. ..... ......... .. .... .... ........... ..... .... .. .......................... 18 Blue Oak/Blue Larkspur-California Phace lia .. ...... .... ...... .......... .......... ...... ............... ...................... 19 Blue Oak/Bajada Lupine-Tree Clover ........ ...................................................................... .... .......... 19 Bl ue Oak-lnte1ior Live Oak/Mission Star ...................................................... ................................. 20 Branch Mountai n Stand Classification ................................................................................................ 28 Branch Mountain Plant Community Descriptions ............................................................................... 29 Blue Oak/Common Fiddleneck-Rusty Popcorn Flower ................................................................. 29 Blue Oak/Wand Buckwheat/Ch ile LolU!--Califomia Plantain ........................ .................................30 Blue Oak/Blue-Eyed Mary-Rigiopappus ........................................................................................ 30 Blue Oak/Mountain Mahagony/Bowlcsia-Woodland Star ............ .......... .......... ...... .... .................. .31 Blue Onk/Hilb ide Gooscbcrry/Ripgut Brome ............... ........... .... ..................... ....................... ..... .n Comparable Communities Across Regions ............. .................................................... .................. ...... 40 Open Stands on Gentle Slopes ....................................... ................................................................ 40 Open Stands on Moderate Slopes ... ................................ .............................................................. .. 4 1 Contents Dense Stands .................................................................................................................................. 4 1 Upper Elevations ............................................................................................................................ 41 Steep Slopes ........................................................... ........................................................................ 42 Regeneration ....................................................................................................................................... 42 Snags and Downed Logs ..................................................................................................................... 43 Appendix-Keys to Plant <.:ommunilies .............................................................................................. 45 A. Avenales Region ...........................................................................................................................