Course Lectures and Labs
Big Beef Creek Field Trip
Over the summer Miles Logsdon, Leon Delwiche, Jonathan Nuwer, and Jill Coyle traveled out to Big Beef Creek to set up some study sites for the Oceanography 452 class field trip. We deployed 6 leaf baskets and at each location took some characteristic site measurements. The class is to be divided into 8 groups of 3. Two groups will measure organic material, two will measure canopy closure with densiometers, two will use the lux meter to measure light penetration, and two groups will measure tree diameters using the DBH's. With this information you will create maps using ArcMap software.
The first step will be to locate each site by using your handheld GPS meter. You will know you are in the right place when you find the 3 feet x 3 feet leaf basket. To use the GPS: turn on power. Check and make sure you are in a position where at least 2 satellites can be detected. Push the 'page' button to get to the next page. This will tell you your UTM coordinates, but might take a few minutes. The best method is to set it down and do something else while you wait. Always re-record your exact position.
1. Organic matter
Once you have located a leaf basket, the amount of organic matter collected on it must be determined.
Dump the contents of the basket onto the tarp.
Now it's time to weigh the material with the scale included in your field box and record your findings in your field notebook, as well as the predominant tree type (ie: alder, evergreen, etc.).
Replace the organic matter and the leaf basket and find the next location.
2. Canopy closure
This will determine the percentage of canopy coverage in each area.
Start with the leaf basket as your center point. Using the tape measure, record how far you go from the center point to take each reading. Hold the densiometer level by lining up the two bubbles inside until they are both in the middle. Line your eye up with the small hole. If you can see any portion of the sky, that reading is positive. If you cannot, it is negative.
Take as many readings as you think necessary to accurately characterize the area. Record each distance and plus or minus in your field notebook. When you are done, count each positive and divide by the total number of readings. That is the percentage of open canopy at that site.
3. Light penetrationThis will determine the amount of light that penetrates the tree cover and makes it to each site. Measurements are made in lux (1 lux = 1 meter-candle).
Standing nearby the leaf basket, turn the luxmeter on. If it is on the first setting (0-1999) whatever number you get should be recorded. If it is on the second setting, multiply the number you get by 10. If on the third setting, mulitply by 100. Take a couple of readings in different positions at each site to get an overall characteristic light profile.
4. Diameter base heightThis will determine an average diameter of trees in the area. With the 'special' tape measure and some help if necessary, wrap it around a tree trunk. Do this for all of the substantial trees in the area of each leaf basket. Be sure to record units used in your field notebook..
When you have finished your tasks at each location, it's time to quit. So-be careful and have fun!!
When you get back to the lab you will have to create a map. I mapped the organic matter information and it looked like this:
more to come ...
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Last modified: 10/17/2007 9:15 AM