28 BULLETIN 1433, U. S. DEPARTMENT OP AGEICTJLTURE 



Within each inclosure four plots were hiid out: (1) A check 

 quadrat; (2) one on which the cover was entirely removed and the 

 •rround trampled; (3) one on which the vejjetation was halt' cut to 

 i-emove the top portion; and (4) one on which the lichen vegetation 

 was picked by hand or, as in one case, scraped to frost. Scraj^ing to 

 frost under winter conditions removed about the top two-thirds of 

 the vegetation, leaving the plant base intact; and picking under 

 thawed conditions removed most of the plant but left the soil 

 imdisturbed. 



Examination of quadrats following one and two years of recovery 

 showed that in all cases where the lichen cover had been half cut, 

 about half the vegetation had been killed and the remainder was 

 still in growing condition. There was no evidence of reproduction, 

 the dead and living cover being so matted that no new plants came 

 in. New growth on the living plants, however, was evidenced in 

 the form of numerous small side shoots on the cut tips and 

 branches. Following a two-year period these new shoots were 

 numerous and averaged about an eight of an inch long; where there 

 had been only one year of recovery tlie shoots were less numei'ous, 

 averaging about a sixteenth of an inch long. The effect of cutting 

 lichens in this case closely parallels what takes place in pruning a 

 hedge or trimming off the top of a tree. 



The scraped-to-frost quadrat was established on April 19, when 

 the surface of the groimd was frozen and covered with a light snow. 

 The snow was lightly brushed away and the lichen vegetation 

 scraped entirely off with a hand x'ake to the frozen surface, leaving 

 the plant base intact and protected by being frozen into the ground. 

 About 2 or 21/2 inches of cover was removed. Later, upon examina- 

 tion following thawing, a cover of half an inch to an inch of lichen 

 plant stubs was found remaining on the area. Examination follow- 

 ing recovery after two seasons showed two-thirds of this cover com- 

 pletely killed and the remainder still showing signs of life. Xew 

 growth in this case as in the area half cut took the form of many 

 fjmall offshoots on the cut tips and branches, a sixteenth to an eighth 

 of an inch long. Xo new plant or reproduction was observed, the 

 matted cover of dead and living vegetation probably obstructing. 



On all the denuded quadrats a scattering rei)roduction was found 

 following one and two j'ears of recovery, in one case about a hun- 

 dred new plants showing on the area following the two-year period. 

 The species occurring, in the order of their importance, were Cla- 

 donm (probably si/Ivafica sylvestris^ rain/iferl/m, and si/lrafica) , 

 Cefrarm eucid/ata, ('. hhnidicay and Stet'eocaulo)i to??u')ifosu»). The 

 i-ei)i'oduction seemed to spring mostly from the old remnants of 

 plants left scattered over the quadrat area, appearing also along 

 the sides of the area by spreading from the adjoining cover. The 

 new growth measured about a sixteenth to an eighth of an inch high. 



The picked ([uadi'ats diffei'ed fi'oiu the denuded quadrats only in 

 degree of denudation. Such nonlichon vegetation as sedges and 

 browse was left standing, with the soil undisturbed, and although 

 the lichen cover was in the main removed, some oi' the jilant base 

 may have been left intact. The beginning of reproduction was 

 evidenced on these areas at about the same rate as on the denuded 

 quadrats. In addition, however, it was found that in a few in- 



