Recent Posts

Post 9.

TRU Open Learning Leave a comment

User:  | Open Learning Faculty Member: 

 

 

 

Post 9. Field Research Reflections.

This project opened my eyes to a feature of the forest that I see all the time but didn’t know its importance. I always liked looking at the advanced nurse logs bearing huge trees on top of the dead wood. There are many examples in parks on Vancouver Island. I thought they were a mere curiosity; but they are an important part of the rainforest ecosystem. My study determined that dead wood hosts a wider variety of plants than the ground around them. They also have more individual plants packed on top of them than on the ground. Plants that grow on the nurse logs tend to be taller than equivalent plants growing nearby on the ground. These trees that died are literally supplying their own replacement.

Some areas for future study could include why some logs and stumps did not host any growth at all or if nurse logs are as important, or even exist, in other types of forests.

 

Post 8.

TRU Open Learning Leave a comment

User:  | Open Learning Faculty Member: 

Post 8. Tables and Graphs

My data was summarized in simple bar graphs. My separate graphs compared plant density, number of individuals and plant height between growth on the nurse logs and ground. Numbers from 21 samples were averaged out. The differences were quite noticeable; I didn’t realize how much until I graphed it. It certainly emphasizes the advantage of using a visual graphic over looking at charts of numbers.

Post 7.

TRU Open Learning Leave a comment

User:  | Open Learning Faculty Member: 

Post 7. Theoretical Perspectives.

I am comparing vegetation growth between dead wood (nurse logs) and the ground. I believe plants growth does better on the wood than on the ground. As for “why”, that probably varies from log to log. All the logs have the advantage of providing nutrients and holding moisture. In some places people walk on the ground but not on the log, so only plants on the ground are trampled. Animals such as deer may come along and forage on the plants at their level on the ground but are not able to reach plants on tall stumps. Some areas have plants that may shade out new plants attempting to germinate. Seeds that land on the stumps and logs are above the level of these competitors. In one spot there was a steep slope that nothing was growing on, except plants on a stump sticking out of the side of this hill.

Keywords: nurse logs, stumps, new plant growth

Post 6.

TRU Open Learning Leave a comment

User:  | Open Learning Faculty Member: 

Blog 6: Data Collection

I collected samples in Muir Creek, an old growth coastal rainforest west of Victoria. The terrain is very rough but there is a path through the site. I used the path as a transect line and sampled in four 30x30m quadrants space 100m apart along the line using a GPS. In each quadrant I located all stumps and logs hosting vascular growth and compared to the growth on the ground nearby. I quickly realized that just counting plants around stumps was not a fair comparison density wise. I measured the diameter of each stump and log, looked for the densest group of plants on the ground and superimposed the surface area of the stump on that spot. That way I could determine if plant growth on the ground was more or less dense than on the stump. I found a total of 21 samples. Only problems were minor. Every visit it was raining quite heavily in the rainforest, which made note taking difficult. I brought a camera to supplement the notes. I discovered previously that this very helpful as long as the picture file numbers are carefully recorded in the notes with each object. Otherwise I would have a couple hundred pictures of stumps that all look the same which would be completely useless.

Post 5.

TRU Open Learning Leave a comment

User:  | Open Learning Faculty Member: 

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.

Post 3.

TRU Open Learning 1 Comment

User:  | Open Learning Faculty Member: 

Blog 3: Ongoing Field Observations.

I plan to study the “nurse logs” that provide a place for new plants to grow.

I observed two stumps and one log that hosted new vegetation. These pieces of dead wood was in a line from the high elevation to the low elevation. This line goes from alders through the large firs and hemlocks and back into another group of alders. I would get a cross section of samples from the different groves.

All samples collected were from the large trees. The alder deadwood hosted some moss but no vascular plants. The amount and growth of vegetation differed among the three samples observed. One stump had a thick layer of moss and berry canes. The log had less moss and small trees on it. The second stump had a pair of cedar trees about 20 meters tall.

Hypotheses: Deadwood undergoes a process similar to succession. Fresh cut or broken wood hosts basic plants, like moss, before shrubs take roots, which are in turn replaced by climax stage trees.

The response variable is the deadwood which would be categorical. The explanatory variable would be the vegetation that grows on the deadwood. This would be continuous as it varies from basic mosses to large vascular plants.

Post 2.

TRU Open Learning Leave a comment

User:  | Open Learning Faculty Member: 

Blog 2: Sources Of Scientific Information.

The publication is “Coarse woody debris decomposition documented over 65 years on southern Vancouver Island”. It can be found at https://www.researchgate.net/publication/249534654_Coarse_Woody_Debris_Decomposition_Documented_over_65_years_on_Southern_Vancouver_Island

This publication is academic, peer-reviewed research material.

The authors are experts in the field. Ken Lertzman has a PhD in Zoology and is a professor at Simon Fraser University. Jeff Stone, Andy MacKinnon and John Parminter are staff with the Research Branch of the BC Ministry of Forests. They include in text references to other studies and their paper has an extensive bibliography.

The paper was reviewed by four referees.

The authors completed a field study which they document in“Methods” and “Results” sections.

Bibliography:

Stone, J. N., Mackinnon, A., Parminter, J.V. and Lertzman, K.P. (1998). Coarse woody debris decompostion documented over 65 years on southern Vancouver Island. NRC Canada.

Post 1.

TRU Open Learning Leave a comment

User:  | Open Learning Faculty Member: 

Blog Post 1: Observations.

The area I have chosen is a piece of municipal-owned land in Sooke, British Columbia. It is a roughly rectangular piece of forested property approximately 150 meters by 300 meters surrounded on all sides by residential areas. There is a gated road from one street through the forest to the other end for use by maintenance vehicles to access a drinking water storage and pumping station. The lot is sloped with an elevation of 60 meters above sea level at the east end and 85 meters at the west. There is swampy terrain at the east which dries out just before the land slopes up. Red alders are the dominant tree at both ends with large western red cedar, western hemlock and Douglas fir in the middle section. Many animals inhabit this area part of the time. They include birds such as hummingbirds, robins, woodpeckers and owls. Herons had a colony here a few years ago but they have since moved on. Mammals that live here include squirrel, raccoon, black tailed deer and black bear. All of these animals are not permanent residents. They tend to pass through and use the area as a sort of shelter, but for the most part they not afraid of humans and roam the nearby streets, yards and other fragmented forest properties. The area does not see a lot of human activity. Maintenance crews drive in a couple of times a week and since their access lane is gated they are the only vehicle traffic. Occasionally neighbourhood kids play in here or cut across as a shortcut between blocks. Homeowners whose backyards border the property have encroached a few meters in with sheds and compost piles. This region sees only a few days of snow a year. The micro climate is so extreme that sometimes the higher elevation gets some snow and the lower end of the property does not. The past few years has seen fire bans from about May to October; it is so dry here that a few sparks would ignite the forest.

I visit this area all the time. My backyard borders it and I am often watching the deer and birds in here. In the spring a hummingbird built her tiny nest on a branch a meter from my childrens’ treehouse. We spent many mornings sitting on the little balcony watching the progress of her babies.

Some areas of personal interest that I may study:

  1. Many animals live in both the forest and the surrounding urban area. To what extent do they rely on the forest?

  2. There is a group of red alders growing in swampy ground. In the past few years they have begun slowly tilting but remaining seemingly healthy until they completely fall over. Why are they doing this now?

  3. There are a few specimens of “nurse logs”, dead wood that new plants grow on. Why do some stumps and logs host new trees and some don’t?

 

Blog Post 5

TRU Open Learning 1 Comment

User:  | Open Learning Faculty Member: 

Initial data collection for my backyard observations of Acer glabrum stand density was done using two types of sampling methods: random and systematic. I did not have any problem with the sampling, but I have decided to tweak my methods somewhat in order to best address my hypothesis.

The gist of my project is to quantify the density of maple trees relative to the large cedar tree in my yard. Hypothesis being that stand density increases the further the plot is from the cedar. For the random sample, I used a random number generator app on my phone to establish 10 plots within the site. For the systematic method, I measured stand density along 3 transects at 5, 10, and 15 meters from the base of the tree at designated bearings of 20°, 40°. And 60° for a total of 9 plots.

These methods both affirmed my hypotheses but for final data collection I think I will use the systematic method, but more comprehensively. The study site is located between 0°-100° from the base of the cedar tree. Using the systematic method, and to satisfy the rule of tens, I will establish transects at 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90° and 100°with one meter plots located at 5, 10, 15, and 20m along each transect. Each plot will be assessed for the number of maple trees within it. So, my field notes will look like this:

This will give me a total of 50 replicate sites with enough distance between plots to be independent of each other. This would seem to be a method that will provide a robust quantification of the density of maple trees at the site, relative to the cedar tree.

Blog Post 3 Ongoing field research

TRU Open Learning Leave a comment

User:  | Open Learning Faculty Member: 

Blog Post 3

I visited Cates Park on November 25, 2017 and the temperature that day was 11 degrees Celsius with light rain and wind coming from the northeast at 6km/hr. I plan to study the density of crows among three gradients including an open grass area with a playground (OGA), wooded area (WA) and second open grass area (OGA2). As you move from area to area the elevation increases. The OGA contained many picnic tables, garbage cans, a playground and leaf piles. The area is very flat with grass covering the entire area. The WA contained many trails within the forest. The wooded area had all the leaves gone offering not much coverage for animals. OGA2 is much smaller than the OGA but also contained two very large tennis courts at the top of the hill. The number of crows within the OGA2 only had 7 crows compared to the OGA that had 13. OGA2 contained only two garbage cans and a picnic bench. Walking between the areas the only observable vertebrates were crows, seagulls, and grey squirrels. These animals were visible in the open area, but none were observed in the forested area. The crows were seen foraging on the ground with the greatest group of them located near garbage cans, leaf piles, and picnic tables. I spent 30 mins walking around each of the areas to observe and count the number of animals in the area. Throughout the walk, there were no visible species in the wooded area. A large reason behind this may be the lack of the cover in the trees due to the colder weather. The response variable for my project will be the density of crows in each of the areas. The predictor variable will be the available food sources from humans and from trees. My hypothesis will be that crows are able to have a higher density with anthropogenic sources available to them compared to natural forested areas.