NATURAL REGENERATION OF DOUGLAS FIR. 
a 
4] 
red cedar and western hemlock very shallow rooted seedlings spring 
up during the first season. 
keeping these species from any but favorable, moist sites. 
This factor alone is very important in 
Seedlings 
of these species must have two or three favorable seasons in order to 
become established sufficiently to insure them against drought. 
COMPETITION. 
In general, Douglas fir is not fastidious in choice of soil, if certain 
chemical and physical extremes are excepted, such as an abundance 
of common salt, lime, or water,-and if it does not have too much 
competition. 
Under favorable conditions Douglas fir adapts itself 
to a variety of soils, and its occurrence depends more on the number 
and species of its competitors than on the quality of the soil. 
Douglas 
fir seedlings have a number of strong competitors, and usually the 
competing species have the advantage in endurance of shade or 
resistance to drought.1* The common and most important competitors 
are listed in Table 18. 
TABLE 18.—Important species in the understory of the Douglas-fir forest. 
Scientific name. 
ACE TICINCIN ALUM UTS Wage ps eats ees ete ere ayaa 
UN CETPEL Oru, OTE rage ee ee oN Ran ee Ue ipa 
AAceH MackophyliiumyPurshis a eee es se eee eee 
Alnus oregona Nutt.........-..- SSN TOR I oat 
Apocynum androsaemifolium L...........--..----..-- 
Aretostaphylosamanzanita Party... 22 042.2. 55.2522 222: 
Arctostaphylos uva-ursi (L.) Spreng .-.....----+---+--- 
Castanopsis chrysophylla (Dougl.) A.DC....... Bae Ge 
Ceanothus cuneatus (Hook.) Nutt..................--.- 
Ceanothus integerrimus Hook. & Arm............--.--- 
Ceanothus prostratuses empl ies Ie ss Omicini 
Ceanothus sanguineus Pursh.............2....1.....2- 
Geanothus-velutinus Dougle 4 4s .5- 3 segs eee ae 
Chamaenerion angustifolium (L.) Scop...........--.-- 
Commus) miata Adee eos oa Ce Ys OS a8 once 
Eriodictyon californicum (Hook. & Arn.) Torr......-- 
Gaultheria shallon! Prumshh yes. 2 ates ee ea 
Minnaeagamenicanayh OnbeShs 2240422 sae ee eee 
Miyricaycahitonicay Chant eee he tigisgee 2i se ee AEE 
Odostemon aquifolium (Pursh) Rydb................. 
Philadelphus gordonianus Lindl 
Ropulussrchocarpasetooks y) 48 oe. a nein 
Prunus emarginata (Dougl.) Walp !......2...0.0..522- 
Pteridium aquilinum pubescens Underw.............. 
Quercus breweri Engelm 
Quercus californicai@lorn)iCoope:-- 544. 2 esa. 
Quercusichuysolepispluiebmn ys ogee ee a ea tea 
Quercus densiflora ieiooke <7 Army ihe oy 
QuercusigarnyanaeDousil ee ee ir vars es Oa eas 
Quercus sadleriana R. Brown Campst...-...........-- 
Rhododendron californicum Hook............-..-.---- 
FVUDUS DAbVALOLUSWNU bE ass 2 oe) ao) a le iad 
Ribusspectabilisybursh eee sa. - fas eh I es SS 
Salix spp 
Sambucus callicarpa Greenes. 2. sa2-/.ssce eee boo 
peal glauca N wt sich APO Bi UND ay Re Pe 
TDM OMLeATpOsSeMOllisMNULL: 2452 eS ees ea ey 
Thuja DlicatarwD ons eA VAT EEE ts Bee 
Tsuga heterophylla (Raf.) Sargent.........-........-. 
Umbellularia californica (Hook. & Arn.) Nutt.......-- 
Vaccinium membranaceum Dougl 
Vaccimum) ovalifoliuim: J. H; Smiths. 2c seco see 
a See Figure 1. 
5, southwestern Oregon. 
Region in 
nee it 
orms a 
Common name. competing 
ground 
cover.a 
Minermaplegec’ <2 ght Oia oa ea: 12535405. 
Diwierd maples. aces Oey i ae eee 125354, 5 
Broadleaf maple.............-.---- 1, 2,3, 4, 5. 
MEV neal Cl rete Sea Oe oP TEN aera Sees 1, 2,3, 4, 5. 
Wosbanep Hwy hee ae eae Nor ees 1, 2,3, 4, 5. 
INT ZA TAG ayy uel ee ey ete ames clin a of 
Kinnikinnicke 1 witewes. cI. 34g 
Goldenleaf chinquapin........-... 1,3, 5. 
Wedge-leaf ceanothus.........-.-. el Owos 
Pl we brush sat is espe Wee Goer e. 125.3, 4:0 
Mein allasim atseesc ieee sais pene IG Sie 
Red ceanothuspee4y: 3. ass kee 1, 2,3, 4, 5. 
Sel eke. CeanObaussee em ees 1, 2,3, 4, 5. 
ITO WCC Ge a ENN A 1, 2,3, 4, 5. 
Western dogwood........----...-- 13 
NICE WAN SIG Aerts ooze aati sy tah Sune Sub: 
SEEN Me BAA a Be oe nt ee re Sate he eh a 132, 3; 4515. 
White hawkweed..........-....-- 1; 2,3; 4,5. 
American twin-flower.........---- 1, 2,3, 4,5. 
California bayberry..........----- 1, 2,3, 4, 5. 
Mall Oregon erapesss 22h 1 2535405. 
SRS UaVEt Ey Mae eee wis Ue Pe wal Re ree pe aay ys 
Black cottomwoodsn.. eke sere APY Cie) 
Wall cCherisy<t isch aoe 28 eae a Ail Paka ace osco 
Western brake-fern............--.. | 1,2,3,4, 5. 
SHOUD AUAG RW geht Seine eC et Mn ape Sea ak 3. 
@aliforniaiblack oak. cee 022 ee: Bo: 
CanyonilivierOa kt ajsen. sos ae BH Or 
Tambarkvoakwyes. Bese. sees Ns BaD: 
Pacific post oak 1,3, 5. 
SACS TRO kee yet tae Ok Ns Bee AN OF 
California rnododendron........--- [203.45 5. 
Phim blebennyee se ye eee oe aes 1, 2,3, 4, 5. 
Salmtombermys-eissts 24s. es tae ALS OMe 
IW O WISHES Anse tic ie ween, | 1, 2,3, 4, 5. 
Pacific redberry elder... .........-- | 1, 2,3, 4; 5. 
Taleo ericce. ores fa Wee yee pclae | 1,2,3, 4, 5- 
STOWDCHRY eee ee ee eee a 1, 2,3, 4,5. 
Western redicedar! 42°22. 224s: | 1, 2,3, 4,5. 
Western’ hemlock /o2 4 2b. 0 oe | 1,253, 400. 
California laurelss os se ues 5 Po ks leat 
Thin-leaf huckleberry ....---.----- | 1,2,3,4, 5. 
Malishucklebery ees ss se cee Se see | ok aoa. 
Tall red huckleberry ..-.-.-.-.----- | 10-3) 405s 
1, western Washington; 2, western Oregon; 3, eastern Washington; 4, eastern Oregon; 
18 Hofmann, J. V. The Influence of Vegetation on Fora Tree Seedlings. Journal of 
Ecology, 1918. 
