Weather: Drizzly rain and partly overcast
Temperature: ~ 55 degrees F
Time: 7:30 pm
Location: Marsh Island (with notes on Mt. St. Helens and Gifford Pinchot National Forest)
For this week's blog, I tried to explore the fungi and lichen that occupy Marsh Island, but unfortunately there seems to be few. I will primarily reflect on my field trip experience over the weekend. I spent Friday, Saturday and Sunday exploring the S. Cascades Range with my ESRM class on old growth forests, led by Jerry Franklin. He is the foremost guru of old growth ecological management, and I feel many of the things we discussed have a strong connection to natural history. Since this is a blog about the Puget Sound, this information will hopefully be interesting to you!
First, I have included the ID of two lichen species that can be found on Marsh Island, but to my dismay, the list is short:
Waxpaper Lichen (Parmelia sulcata)
Hooded Rosette (Physcia adscendens)
Our field trip to the S. Cascades began with a visit to the Johnston Ridge Observatory at Mt. St. Helens. We discussed the landslides and lahars that followed the eruption in May of 1980, and the impacts on the Toutle river and surrounding valley. The tephra ash falls and pyroclastic flows further contributed to an altered landscape through a severe disturbance regime. I learned that lateral blasts gave information to volcanologists about past eruptions and provided new, previously undocumented data. The legacies that remained after the blast gave ecologists the most clear understanding of eruptions and their role in succession. The landscape is incredibly diverse in the Cascade range-- no species of plant was lost completely. The new habitats created (like early-seral) provided non-forest landscapes for species like elk to move in. The Mt. St. Helens area now hosts the largest herd of elk in the state! Congress created the Mt. St. Helens monument, and even Weyerhaeuser supported it due to boundary disputes. One interesting impact of the eruption was the alteration of Spirit Lake to avoid overflow. The lake had originally had the Toutle river as its outlet, and engineers didn't want the lake to overflow and breach after the eruption. They drilled a tunnel at the desired elevation to maintain the lake level since the river could no longer serve its original function. This is a fascinating example of how humans can alter the natural history of a region, and participate themselves in landscape shifting events.
We spent the next two days at Wind River and in the Gifford Pinchot National Forest. We visited the crane the Jerry Franklin brought to the Wind River experimental forest to observe the high canopy. The crane is currently being used for measuring carbon exchange in the atmosphere, and noting the diernal variation between day and night. Continual data collection provides them a lot of information about the role of old growth forests as a carbon sink. Although a lot of decay and respiration occurs, the outcome is an overall uptake of carbon rather than production. With climate change, these conditions could change. Drought causes stomata to close during the day, meaning less photosynthesis and less carbon dioxide uptake can occur. Assimilation is occurring constantly, even when above ground growth has stopped. Below ground processes allow the flow of water and nutrients available to a tree.
Part of the study involves the life of the tree, but also the death. We learned that 97% of Douglas firs (the dominant species in primary succession of these forests) die from butt rot, bark beetles or true uproot.
The Yacoult burn in 1902 left a lot of big snags and downed wood in the forest site. The Western hemlock served as a seed source, and now the forest is in a stem exclusion stage because there is dense growth of W. hemlock. The fire was caused (as many in this region are) but a synoptic weather pattern and suppressed fires. The weather pattern brings dry hot air into the forest and dries out all the fuel sources. Since smaller fires have been suppressed, fuel has built up and creates an immense fire. In some forests, thinning takes place to allow forests to become more complex. The lack of density can come from a pre-commercial thinning, which means the trees weren't big enough to use for anything and it helped shade intolerant species to grow up.
Franklin has made it clear that timber production will never again be a primary goal for the forest service. Rather, his concept of ecological forestry has started to take hold as the new approach. One interesting aspect of his approach to dry forests (East of the Cascades) is restoration for pre-adaptation. Historically, ponderosa pine dominated the dry forests because natural fires were frequent enough to eliminate the Douglas firs and grand firs. With fire suppression, these tree species have grown up and are threatening the Ponderosa pine. In restoration efforts, we can remove the trees that are not meant to grow in those conditions and instate fire as part of the management regime. This will better prepare the region for climate change that will make forests drier and bring synoptic weather patterns more often. The key message I got from this field trip was: Don't let the perfect get in the way of the good. Cutting trees is necessary, and sometimes even important for the ecosystem.
Marsh Island was flooded more than ever this week, so I plan to wear boots next week!
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