Journal Entry #8 - May 24, 2011
UW Campus
Seattle, WA
Weather: Cloud cover, light raining off and on.
Today was the first day of tours and we learned about the trees and moss found on campus. The first group was the trees and we observed quite a few species, to include: horse chestnut, Pacific Madrone, Douglas fir, Deodar cedar, Big Cone Pine, Gingko Biloba, English elm, and Monterey pine. Some interesting facts: horse chestnut produces small, white flowers with red spots and the seeds are called conkers – this tree is native to Europe. The Pacific madrone was actually cold to the touch, which was rather cool, and fruits edible berries, the leaves have medicinal uses, and this tree needs forest fires to maintain health. The Douglas fir is actually a member of the pine family and likes rocky soil and is fire tolerant. The Deodar cedar is native to the western Himalayan region and the fist-sized cones are produced only by female or bisexual trees; they are very durable trees and can live for several hundred years in poor soil conditions – they are also symbols of divinity in Asia. Gingko Biloba is native to China and is the oldest unchanged tree on earth in terms of genetics, ginseng from the tree is commonly used as an aphrodisiac in eastern medicine. Big cone pine produces the biggest cones of all pine species (hence the name) and the needles are long, thick, and in 3-needle clusters; they also produce a natural herbicide: terpene. The English elm reproduces through translucent sucker saplings, and the wood from this tree is a commonly used material for coffins. This tour was interesting, and during the observation of the horse chestnut, we were able to get a tree rubbing from the bark. Furthermore, I had always seen those little metal tags on some trees and I wondered what they were for – I found that one can identify the tree species by recording the number on the metal tag at www.assetmapper.com. I will definitely be exploring more of the trees on Seattle campus, there are so many!
The second group was the mosses and lichens. We learned that there are over 700 species in the PNW as they prefer wet, shady climates with slightly acidic soils. They rely on wind and water for dispersal and they can primarily live in any ecosystem, except marine habitats. They can go dormant for long periods of time and they lack a traditional root system. There were three groups examined: liverworts (which open into segments), mosses, and lichens (harder to the touch with no spores). We first went to the Burke-Gilman trail behind the greenhouse and looked at the different mosses on the bridge. We observed red roof moss and learned they were most common after fires. They were several kinds of mosses in this area and we didn’t have time to identify them all. Next we moved to the area near the bee house to learn about where mosses evolved from. This was very interesting! Bryophytes evolved from green algae and used to be submerged in water and as a result, they do not have a system for storing and distributing water. The haploid life cycle is the most common among algae where moss is furnished with one set of chromosomes. They are spore producing, which distinguishes them from other plants, and the stems/branches serve as sex organs. Fertilization can only occur with the presence of water, as sperm can swim – although they lack vascular systems and acquire nutrients from absorbing air and water from their surrounding environment.
The lichen skit was my favorite part of the tours all day, and was very amusing to watch. I learned that lichens respond very strongly to air pollution, and hence do not do well in urban areas where air pollution is prevalent. Because of this, they are strong indicators of air quality and the more stress they incur; the less they produce reproductive parts. Fungi and algae have a symbiotic relationship. Historically three broad categories of lichen have been acknowledged: crustose (crusty), foliose (leafy), and fruticose (shrubby) – and general rule of thumb: the less complex they are, the more tolerant to pollution they will be. They are the first indicators of change related to pollution and can be used in historical imagery analysis. Some are nitrogen fixers and respond negatively to sulphur dioxide – acid rain, heavy metal, smog, and radiation. Lichenization is the term used for symbiotic relationship between fungi and algae – where fungi provides the home for algae, and lichens live inside the fungi. In this we see that algae couldn’t exist without lichens.
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