|
| |
|
I've grown up in Colorado, a place known not only for its mountains and skiing, but also for its substantial groves of quaking aspens. For most of my early childhood I had a small grove of my own in the front yard, which grew so quickly and efficiently that we had to remove it for fear that it would crowd out the neat rosebushes and pruned chokecherry trees. My interest in the growth patterns of aspen trees probably started there, though I did not yet realize it. This particular research project started last year, when I was in seventh grade. Our class was on a two-day-long camping trip, with the assignment to choose an experiment, formulate a hypothesis, and conduct an experiment that either proved or disproved the hypothesis. We asked the question: Is an aspen's diameter affected by its distance from the grove's center? Knowing that a grove is all one organism and that it spreads using "shoots" from its root system (as well as by seeding), we believed that it would make sense for the grove to spread outward, with the oldest and thickest trees near the center and the younger, skinnier trees close to the perimeter. These assumptions lead us to our hypothesis that the farther away from the center of the aspen grove a tree stands, the smaller its diameter will be. After we formulated our hypothesis, we discussed various ways to go about collecting our data. We agreed on the method: first, mark the perimeter of the grove with flags, then find the northernmost, southernmost, easternmost, and westernmost points of the border. We then measured 30 meters inward from each compass point and marked those points with flags. Within the border of new flags, we would choose the tree with the largest diameter (the eldest tree). That tree would be considered the center of the grove. From this hypothetical center, we would run a string directly north, south, east, and west, marking any tree within one meter on either side of the string with another flag. We would then measure each marked tree and record its distance from the center of the grove, as well as its diameter. (The data was recorded separately for each direction, and was then analyzed back at school.) |
 Map showing the grove location at Golden Gate Canyon. (Click to enlarge) We were camped in Golden Gate Canyon State Park and went on a hike to find a grove to study. It was a clear, sunny fall day, and we set out with hopes of collecting the data needed to prove our hypothesis. We stopped a few times along the trail to explore aspen groves, but most of them were oddly shaped, or divided by a road, stream, or path. We wanted a more circular grove so that the number of data points we collected would be close to the same for each direction. We had walked a little more than a mile when we saw the ideal grove. The leaves of all the trees were the same color, which our teacher Susie Steele told us was a sign that the trees belonged to the same organism. Its perimeter shape seemed circular, and there didn't seem to be any complications involved with pathways or streams cutting through it. Out toward the edge of the grove the smaller trees were recovering from their first time being gnawed on by elk. Many people, even those who have lived in Colorado for years, do not know that the black scars that distinguish older aspen trees are caused by hungry elk in the wintertime. The trees toward the center of the grove had fewer new scars on their trunks because most of their bark was already scarred and ripped, torn off in the strips that indicate elk chewing, but also with unique eye markings where their branches had been broken off. The eerie eyes watched us warily as we explored. The dominant grasses that were intertwined among the aspens crunched under our feet, and the canopy of gold watched our movement from above. We decided that this was the perfect site to collect our data. |
        
|
|
