Mt. Skokomish wilderness

The Hamma Hama River with the Mt. Skokomish
wilderness in the distance.

After a few years living in the Pacific Northwest, I finally made it up to the Olympic peninsula in Washington state for a short vacation with the family earlier this month. Olympic National Park is the main attraction on the peninsula, but there are several wilderness areas immediately adjacent to the park. We had several days of outdoor adventures in Washington that I will highlight in the next couple of posts.

Our first night on the peninsula we camped at the Hamma Hamma campsite in the Olympic National Forest on the SE side of the mountain range. The Hamma Hamma River tumbles out of Mt. Skokomish wilderness to flow into Hood Canal. I woke up about 5:30 AM to the sound of all sorts of singing birds competing with the sound of water rushing down the river. After breakfast and packing up camp, we continued up the valley to the end of the road at the Mildred Lakes trailhead. We hiked several miles into the wilderness on a steep trail that was only poorly marked in several sections. Most of the trail navigated through dense coniferous forest. Because the kids were with me and we had no real navigation guides, we turned back when following the trail became pretty difficult. Unfortunately, I think the point at which we turned back was only a short distance from the intended destination so we missed the lakes this time around.

Adiantum aleuticum.

Along the trail, there were all sorts of coastal temperate forest species present, virtually all of them familiar to me from my explorations in Oregon. Trees included douglas fir, western hemlock, cedars, vine maples and alder. Other plant species I recognized included:
- sword fern (Polystichum) and bracken fern (Pteridium)
- deer fern (Blechnum spicant)
- five finger fern (Adiantum aleuticum)
- wild ginger (Asarum caudatum)
- thimbleberry (Rubus parviflorus)
- salmonberry (Rubus spectabilis)
- red columbine (Aquilegia formosa)
- cow’s parsnip (Heracleum maximum)
- false Solomon’s seal (Maianthemum racemosum)
- salal (Gaultheria shallon)
- Castilleja, Trillium, and Clintonia uniflora
- bunchberry (Cornus unalaschkensis)



Wild ginger (Asarum caudatum). Note the single purple flower
below the leaves. The flowers aren't always very obvious
from a hiker's vantage point, so be sure to look under the leaves!

One of the most ecologically-interesting phenomena I encountered was a huge clearing in the forest that appeared after perhaps a mile and a half into the trail. The clearing was several hundred meters in width and ran down the hillside, with an abrupt border of erect conifers. Clearly, this disturbance was a historic avalanche of some sort, perhaps caused by snow or a rock slide. The clearing was full of old woody debris from trees that were victims to the incident and vegetated by shrubby and herbaceous plants such as Heracleum maximum and small trees. Given the degree of re-vegetation at the time of my visit, I guess that the landslide could have occurred some 5-15 years ago.



Avalanche site, with intact coniferous forest to the left.

The role of sudden large-scale disturbances on ecosystem structure is a fascinating topic in ecology. Examples of these types of disturbances include hurricanes in coral reef ecosystems and avalanches or volcanic eruptions in montane forests. Their temporal nature is fascinating – the exact timing and location of these impacts are unpredictable, but the fact that they are bound to happen sooner or later is rather predictable. Large-scale, low frequency disturbances introduce an interesting historic component to why any particular ecosystem is structured the way it is at any given point in time. Once such a disturbance occurs, it resets the successional clock in an ecosystem. An avalanche in a forest may wipe out dominant late-successional tree species and thereby initiate a sequence of colonization that starts with pioneering species that successfully colonize the disturbed habitat.

Such disturbances are also difficult to study in real-time, because they occur on ecological time scales that are long relative to our own lifetimes. In the Pacific Northwest, for example, volcanic eruptions or massive subduction earthquakes may occur only once every few decades or centuries, but they have dramatic impacts on ecosystems. How cool it would be to have something like a time-lapse movie to view hundreds of years of ecological history at any given place!