In most stands, usually within or near a study quadrat, a pit was dug to obtain soil profile 

 description, to determine depth erf the active layer, and to remove soil samples for later laboratory 

 analysis. Basal areas of all stems over 1 cm DBH were also measured. These data in addition 

 to C-A values, help to show the relative importance d the tree species, in most cases the community 

 dominants, within and among stands and areas, and they may also enable rough estimates of stand- 

 ing crop biomass to be made. 



The list of species and C-A values, along with the quadrat location, elevation, and other abiotic 

 information, constitutes a relev^. A relev^ is a meaningful set of data on environmental conditions 

 giving species composition and vegetation structure as \»ell as abiotic conditions necessary for 

 gradient analysis. A series of relev^s from a large number of stands covering the range of vege- 

 tational variability in an area may serve as the basis of a vegetation classification scheme. Sets 

 of classified vegetation types may be positioned on one- to n-dimensional diagrams of coordinate 

 axes which show value ranges of selected abiotic variables. By determining stand indicator values 

 from the data contained in the relev^s, an ordination of the vegetation may be calculated. During 

 the 1970 season, 71 relev^s were obtained. The data are currently being transferred from field 

 notebooks to computer format for further analysis. 



The following discussion is limited to preliminary vegetative analysis ctf the control area 

 located adjacent to the experimental hot-pipe section. 



The results of the hot-pipe vegetation transect survey provide an example d the analysis 

 possible with the vegetation data gathered at each transect site. At the hot-pipe control area, the 

 analysis provides an indication of the physiognomy, or structure, and species composition of the 

 undisturbed vegetation adjacent to the hot-pipe disturbed area. 



The vegetation is dominated by arboreal species throughout. These include birch {Betula 

 papyrUera), white spruce (Picea glauca), black spruce (Picea mariana), and alder {Alnus crispa 

 ssp. crispa). Figure 39 shows the relative importance of these in the 23 0.02-ha quadrats along 

 the transect. Three vegetation types, or plant communities, can be recc^nized. The first, design- 

 ated a birch community, is represented by quadrats 1-8, and is dominated by birch. The second, 

 represented by quadrats 9-14, is dominated by birch and alder and is considered a transition comr.! 

 munity because it includes a mixture of species dominant in each of the adjacent communities. 

 The third community, including quadrats 15-23, is dominated by white spruce, black spruce, and 

 alder and is designated a mixed spruce, or simply spruce community. This community may be con- 

 sidered an ecotone. The status of other woody species is shown in Figures 40 and 41. 



A WHITE SPRUCE OBIRCH 



lOr 



A BLACK SPRUCE 



(LARCH 



2 3 4 5 6 



8 19 20 21 22 23 



7 8 9 10 II 12 13 14 15 16 17 

 QUADRAT NUMBER (002 HA) 

 Figure 39. Cover-abundance values for four tree species in 23 0.02 ha (10 x 20-111) quadrats along 

 the hot-pipe vegetation survey transect. (See text (or explanation of the cover-abundance scale.) 



102 



