FlLDLIFi) AFFJCXS TYPl;; OF FOpST "' ^ .^ , 



Rodents, especialljy inlcs and chipmunks., show a decided pr'jfsrence 

 for se-ads of soras pin^as, and studi5S shoVr that araon^ those produced in 

 the California forests tiie preference vras in the following order :, Sugar, 

 Jeffrey (pinus jeffreyi), and ponderosa pin'^s, and after these, r;hife. fir; 

 and incense ctrdar^ The" last namefj. is eaten in small quantities,^ Though 

 the preference was in tiie order of seed size, that is not the deciding 

 factor, as the relative acceptability was the same when the seeds were 

 reduced to a paste by grinding, 'possibly the ohemic.al coraposition of the ■ 

 seed may play an important part, ' ... 



Cutting decreases the supply of sugar . pine r seed, 'and th.e utiliza- 

 tion of th;, seeds by, rodents is. .high. , As a result^- neafly all th.i seeds.. 

 are taken each year,. The few that are left to germinate find severe and 

 often fatal conoetition witJi bu.-rclover and othei plants that incr'-jased 

 so markedly aftir logging operations, \ •' ' . , ■ . . 



As whits fir se.^d is abundant and only uartially consumed by ro-^ 

 dents, it rf^produces far raorQ readily than do,3s tho'sugar pine. Incense 

 cedar se^d is eat^n in small quahtiti'^s by rodents ' andi*.e-produc.";s well. 

 As a"'r3s.ult of these conditions th) sugar pin^ is 'not negonerating and is 

 being r'jplac )d by th j lass commercially valuable, vrhite fir and. incense 

 cedar;, Apparently regeneration of th^ sugar pine occurs only at I'idoly 

 separated periods. Probably reproduction is th.j result of coincidence 

 of a he£.vy seed cror; and a lov^r sood-roating animal, population in a year 

 follovj-od by conditions suitably for gjrminatipn of seedlings. 



Farro'';!', in liis work on rabbits in England, :Cound good indications 

 that those animals have b-ien responsible for the change ^ -of 'many, areas 

 from for^.st'to grassland.' Thor^ is a stron^ possibility, likewise, that 

 in Carlifornia soiu,^ sugar pin^-fir-rincens ; c.-.idar: as-socations may ;.,ive v^y 

 to ."i.r-fcodar because, of activiti-.-^s of seed-oating rodents, 



■. , ' . ./'. RESULTS Oil CitLIFO .'lix JTUDY AR'iAS ' 



The offjcts of chan,_;.js in forest composition 'are far reaching:*- 

 Opening forests burning or cutting incroa.s.js... f.ood and' sh'jlt ..r 'f or many 

 animals. Shrubs valuable for d*-jor food thrive,' mor/ 'odgjs are created, 

 and thj doer increase, .In 1924, during^tho outbreak of foot-and-mouth 

 disease, 22,000 do. it wc;ro kill ;d in onj of the jf.;.:o ts to stam.p ^out ...the •• .-. 

 malady, B':foro and after :"th; deer i-ere ki-ljl.-'d, . lumberitfig ' op-jno'd" largo . l 



portions of thV: forest, so that thj habitat b.;Cc:mo v.;ry favorable, .Despit® 

 lecal 'extirpation, do jr are agair abui dant, and' th,ir'j ■ is a 'possibility that,- 

 th.3 summ:-. r . rang i has a carrying capacity in; -txc; ss : of th'.at of , thj i/ii ter : 

 range'. If this proves tru), ovorgrazir g of th.; \^lnt;r rangj yd.ll,.follov/"<. 

 As the .cut'T-oyor' a,r /a-s- ''grow up- tc forest tro'.>s^ c.onditidns foi^'doer "n the 

 summof range also will become loss 'f.a.vor!ablo ; -Good browse speclo.s jnay then 

 show the offoqts of ovorgrazing and i^inally -disa'ppear. Tha 'so.p.d-oati.ng 

 rodents, by limiting sugar pine ro production., and permitting relativj in- 



