PE EIE[R-Rg RESEARCH ON - HJ Andrews Experimental Forest

Figure 1 . Aerial photo of Findley Lake basin indicating
drainage basin of upper lake and two smalle r
ponds.
cepts each of the other two basins as well a s
26 percent of the watershed directly .
The soils of the watershed have bee n
mapped by Bockheim and Ugolini (n .d .) .
Many of the slopes range from 30 to 40 percent
; widespread talus accounts for 16 .2 percent
of the total basin. Soils of mixed materials
are divided as forested, semiforested, an d
nonforested ; they account for 56 .2, 4 .3, an d
1.6 percent, respectively, of the total basin .
The residual soils on the ridges are 17 .5 percent
forested and 4 .2 percent nonforested .
Del Moral (1972) has completed a vegetation
survey of the watershed . Seven vegetation
types were distinguished and their distributions
mapped . Most of the area is timbere d
by relatively homogenous old-growth Pacifi c
silver fir (Abies amabilis) .
Taber' has conducted a preliminary survey
of the terrestrial vertebrate activity in the
1 P. R. Olson, J . S . Bockheim, F . C. Ugolini, an d
others . A terrestrial-lake interface program, Findle y
Lake watershed. Coniferous Forest Biome Interna l
Report No . 25 . (In press .)
watershed. The elk (Germs canadensis) and
pikas (Ochotona princeps) have a noticeable
impact on the vegetation of the basin . Migratory
,vertebrates such as deer (Odocoileus
hemionus), elk, and birds could influence the
movement of nutrients in or out of the basin .
In addition, the elk activity in some of the
meadow areas has obviously disturbed th e
soil .
Snow accumulations of 4 m often occur i n
the Findley Lake basin . The open surface
period on Findley Lake is approximately 4
months. The lake frequently is not free of
snow cover until late July and usually start s
to close about mid or late November. A thin
layer of ice will often form in early November
and soon thereafter, snowfall will cover th e
surface. The snowfall accumulates rapidly and
insulates the surface from additional freezing .
The latent heat of the lake water thaws th e
ice layer originally formed and the snowpac k
effectively supports itself . As snow accumulates,
the light penetration is greatly reduced .
In February of 1972 there were 2 .9 m (9 . 5
feet) of snow ; the light readings beneath th e
snowpack were approximately 1 .4 lux-0 .0 3
percent of the surface illumination . Th e
oxygen concentration of the water colum n
was close to saturation except within 2 m o f
the bottom where the oxygen decrease wa s
quite abrupt. Temperatures at this tim e
ranged from 1 0 C at the surface to 3° C a t
25 m .
Limnological surveys were performed b y
Welch (see footnote 1) on a monthly interval
during the open summer period . Findley Lake
is extremely clear with visibility extending to
depths of 15 m . Since the lake is relativel y
deep (about 28 m) and unproductive, th e
hypolimnion during the summer period remained
well oxygenated . Maximum water
temperature noted at the lake surface durin g
the surveys was 18° C . The dominant zoo -
plankton found was Diaptomus shoshon e
with a modest population of Holopedium
gibberum present early in the season. Th e
Diap torn us population persisted after 3
months of snow cover .
The analysis of water samples b y
Spyridakis (see footnote 1) is covered mor e
extensively by Taub et aL(1972). Mean values
16