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Blog 5: Design Reflections
My original idea was to sample deadwood (logs and stumps) and determine if a form of succession occurred on wood. I took samples from the forest but ran into several problems:
Location. The area is not too big. For this idea a larger area probably has to be sampled.
Human activity. I sampled a location that I knew had some human activity and areas that looked untouched. There seemed to be less wood on the ground than I expected. I since discovered that some people who living around the parameter of this property do go in on occasion and remove fallen trees for firewood. Since the forest isn’t that big and the area surrounding is over 40 years old too much of the wood may have been removed to capture samples of vegetation growing on logs.
Order of plant growth. I thought of treating fresh cut or broken wood like bare rock. Lichen would grow, followed by moss and then vascular plants. I saw some fresh stumps in this forest that had rotten wood in its cross-section and tiny tree seedlings growing in that. I did not take into account this factor, that some wood might already provide a habitable location for tree seeds to take root immediately after death. I also saw one stump beside the access road that had soil piled onto it during road maintenance in the last couple of years that was host to a tree seedling. The wood under the soil was still rock hard.
Wood that does host growth. The wood that did have growth was all conifer (cedar, hemlock, Douglas fir). None of the deciduous alder deadwood in my survey areas had growth. Logs outside of the survey did have some moss but nothing else. It appears, in this forest anyways that only the conifer trees are hosting new vegetation. Since the coniferous area accounts for only one third of this forest then the study area shrinks even more. There didn’t seem to be any rule that determines which deadwood plays host to vegetation. Other than type of tree that becomes nurse logs, there doesn’t seem to be any other rule about which ones will host vegetation. Growth occurred on a mix of wood, both new and old. There are stumps bearing more advanced vegetation that are clearly more recent than some other stumps that are very old and only bearing moss. One stump that does host a couple of fairly tall cedars still bears a loggers notch (part of a method of logging by hand use up to the 1930’s), but other stumps nearby even more decayed didn’t have even moss.
Time. The report in my Blog 2 was about a study on decaying wood in an experiment that had been ongoing for 65 years at the time of publication. Perhaps succession on dead wood would be best studied from fresh logs and stumps and the growth documented over time, as opposed to finding specimens with no know history and trying to piece together a pattern of succession.
Modification of idea. I visited another location in my region that has the same type of coast rainforest. This area is larger and is a regional park. There is also some known historical background. In 1913 an above ground concrete water pipe was laid through to supply Victoria. A strip of forest on either side was cleared so that trees wouldn’t fall on the pipe. The pipe was decommission many years ago but was left in place and the forest on either side is closing in to reclaim the gap. I thought this might be a better place to find samples of deadwood with successive stages of vegetation growth. I found a photograph of the pipe installation crew at work in 1913 with a giant stump prominent. I went out to the exact location and after much difficulty found the very rotted remains covered under thick shrub. Most of the other original stumps were also gone. There was also a lack of logs laying around. I did notice a pair of newer stumps in a clearing that showed something interesting. The ground in this small clearing was covered with shallon shrub too thick to even walk through. The stumps, which rose above the height of the shrubs, stood out because they bore several varieties of plants. None of the plants were shallon and they were the only plants in the clearing not shallon. On the way out of the park I noticed that the few other stumps and logs along the trail bore a greater variety of plants than the ground surrounding them. I went back to my own study area and took another look at my original samples. The logs and stumps with plants had more growth on them than on the ground around them. I am going to concentrate on determining if fallen wood is more habitable to new growth than the ground. The study area does see some human activity and there is a heavy concentration of deer that does feed in here. The park I came from also sees lots of activity in the form of hiking and mountain biking. I will locate an area to pursue this idea further.
