Journal Entry 17
Trees/Mosses and Lichen group presentations 5/22
Weather: initially dry and comfortable, but subsequently rainy and cold.
The first group project presentations went today, and consisted of the Trees group and the Mosses & Lichens group. The tree group started off with a few unique trees found among campus with a brief history of the species and their roles in society and how they came to be on campus. The first presenter group I was with dealt with exotic species that had all been planted horticulturally for aesthetic purposes. Among these were the Ginko tree, which was originally from China, but thought to be extinct in the wild worldwide. However, it is grown so common horticulturally that they are at no risk of extinction or anything of that nature. They are an extremely old species, and have remained evolutionarily constant since for thousands of years, more so than most plant species. We then learned about the English Elm, which is a common tree on campus. It is an extremely popular tree in many parts of Europe for use in cities and aesthetics, but is native to Italy. It is associated with death because of its tendency to spontaneously drop branches, which can often have fatal consequences. Then we went toward the Heron rookery, where we came across several native species of trees. We began to talk about the uses of trees like the Western red cedar found there, which the natives used for clothing, rope, boat carving, and many other purposes. Because of its easy to peel bark, the western red cedar became essential to the daily lives and subsistence of native Americans in the Pacific Northwest. Another significant tree we discussed was the Giant Sequoia near the rookery, which is noted for being massive and ancient, as well as being an exotic species that was planted on campus by a professor many years ago. The species is native to a particular location in California, but has somehow managed to survive quite well in the Washington climate for all these years.
We then learned about several trees, including the horse chestnut (aesculus hippocastnun), big leaf maple, pacific madrone, and douglas fir. All of these plants are native to the Pacific Northwest and are relatively common throughout the area (with the possible exception of the horse chestnut, I do not recall for that). The pacific madrone was the most fascinating species to me because of its reputation as the Refrigerator tree, a nickname resulting from its lack of deadwood insulating the cool water rushing through the tree’s base to the branches. As a result of this lack of deadwood, the bark of the pacific madrone is consistently cold, even on hot days, hence the name refrigerator tree.
Additionally, the mosses and lichens group went as the rain began, which was appropriate given one of the natural conditions necessary for moss and lichen growth is rain. The group described the roles that fungi and algae play in conjunction to create lichen. The fungi act as structures to house the alagae, which then synthesize nutrients which keep the fungi surviving. This symbiotic nature is conducive to both parties in the system known as lichenization. More complex pairs of fungi and algae create less stress tolerant lichen to external stressors like pollution.
Mosses are briophytes that take from a quarter to half a year to mature. Mosses evolved from green algae long ago and now reproduce through the use of spores, much like fungi. Modern day ferns evolved from mosses.
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