lands in volcanic regions of the Pacific 
Northwest. 
Further insight into recovery mech- 
anisms will come from observations 
of revegetation in sites on the periph- 
ery of the directed blast. The ridges 
and glacial valleys in these areas es- 
caped the debris flow and pyroclastic 
activity. On ridges above the South 
Fork of the Toutle River, for example, 
the few lodgepole pines at timberline 
were killed by the scorching blast, but 
the lush herbaceous vegetation that 
normally dominates these ridges, in- 
cluding the yellow penstemon {Pen- 
stemon confertus) and the broadleaf 
lupine, returned with no apparent ill 
effects. On the other hand, the glacial 
valleys below the ridges, scorched by 
the directed blast or scoured by mud- 
flows resulting from melting glaciers, 
lost most of their vegetation. Nor- 
mally, these valleys support plants dif- 
ferent from those on the more exposed 
ridges, but ridge vegetation is now 
the most likely source of seeds for 
the newly exposed terrain. Mountain 
glaciers such as the ones that formed 
these valleys ordinarily retreat slowly 
enough for valley vegetation to keep 
pace. When Mount St. Helens erup- 
ted, however, the rapid melting of the 
glaciers not only exposed large areas 
for the first time in more than a cen- 
tury but also washed away most veg- 
etation below the glacier. Thus, in the 
absence of species specifically adapted 
to the valleys, ridge species may ex- 
pand their habitat and create novel 
assemblages in the valleys. 
Mount St. Helens is so young and 
its environment so harsh that even un- 
der normal conditions only the more 
generalized and stress-tolerant plants 
can survive. All plants common to the 
upper slopes display adaptation to un- 
stable or chronically disturbed envi- 
ronments: deep taproots, buried grow- 
ing points, large storage reserves, and 
good dispersal mechanisms. There- 
fore, although ridge-dwelling plants 
may under normal circumstances be 
competitively inferior to valley dwell- 
ers, they may be physiologically ca- 
pable of surviving in the valleys. I 
plan to monitor the development of 
the upper glacier valley vegetation to 
see whether plant communities com- 
posed of ridge species do develop. 
Their existence in the valleys would 
be strong, although indirect, evidence 
for the importance of competition in 
stressful environments. 
Of all the regions on the moun- 
tain, the most severely affected was 
the blast zone immediately north of 
the crater, including Spirit Lake. Ev- 
ery type of volcanic behavior dis- 
played by the mountain has assailed 
this terrain. All life was seemingly 
obliterated. Trees were pulverized and 
soil vaporized. Yet, even here, life is 
returning. Forest recovery will be slow, 
but it will happen. Soil development 
will require the establishment of mush- 
rooms, lichens, and pioneering herbs. 
Seed and spore sources are scarce but 
a few pockets of vegetation remain. 
A protected ridge beyond Abraham 
Plains, on the eastern edge of this 
area, for example, supports some silver 
firs and a few areas of herbaceous 
vegetation. 
Higher terrestrial life may be scarce 
in the blast zone but dead organic 
matter is abundant, and such a re- 
source is never unexploited for long. 
Here, where many humans died, 
where entire ecosystems ceased to ex- 
ist in a matter of seconds, Dave Hos- 
ford of Central Washington State Col- 
lege has found a mushroom, Autra- 
cobia melaloma, growing from the 
ash, slowly decomposing organic mat- 
ter found there, and beginning a ter- 
restrial succession. 
Most of the biological action in the 
blast zone, however, is taking place 
in lakes. Spirit Lake, once a pristine 
and clear body of water and now as 
appealing as a sewage lagoon, teems 
with microscopic life. Bob Wissmar 
of the University of Washington, who 
is conducting a systematic survey of 
the affected lakes, has pointed out 
that the water in Spirit Lake was to- 
tally removed by the force of the de- 
bris flow and replaced by a hot, muddy 
slurry of ash and debris. Thousands 
of trees, blown off the mountain and 
washed into the lake, have provided 
the basis of a new aquatic food chain 
on the clogged water surface. As the 
water cooled, blue-green algae and 
bacteria were the first active organ- 
isms, but decomposing anaerobic bac- 
teria and protozoans now' dominate the 
biota. The slowly dissolving organic 
matter has reduced the oxygen content 
of the lake and continues to release 
prodigious quantities of sulfur dioxide, 
the smell of which permeates the py- 
roclastic zone. 
Many years will pass before Spirit 
Lake and other profoundly altered 
lakes return to a semblance of their 
preeruptive state. Recovery will be 
faster in smaller, higher lakes, which 
were more thoroughly protected by 
the snowpack. Higher lakes not hit 
by debris flows or mudflows were pri- 
marily affected by ash fallout and re- 
ceived only limited amounts of organic 
matter. 
Ephemeral lakes, laden with organic 
debris and silt, pockmark the debris 
flow that settled into the North Fork 
of the Toutle River. These lakes were 
quite warm throughout last summer, 
and decomposition in them was ram- 
pant. A witch’s brew of phenolic acids 
and tannins, smelling strongly of creo- 
sote and turpentine, is still draining 
from them. Tracks of elk, deer, and 
coyote are frequently encountered on 
the debris flow where little food is 
evident, suggesting that the animals 
may well be in search of water. Un- 
fortunately, the quality of the water 
in ephemeral and permanent lakes is 
suspect. On one occasion, I found a 
45 
