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Each time I hike through the Wasatch Mountains, I cannot help but be impressed by the diverse vegetation types. In particular, as I hike up Big Cottonwood Canyon in the Wasatch Mountains, beginning at the mouth of the canyon and ending up at Brighton, I notice that there are distinct elevation zones that characterize the distribution limits of most if not all tree species. There are some clear patterns regarding the lower elevation at which a tree species first occurs and upper elevation at which that tree species disappears from the vegetation.
One strange but consistent observation that I have made is that the elevation at which a tree species first occurs on the south-facing slope is not the same as where that tree species first appears on the north-facing slope. Similarly, at the upper distribution limits, the trees disappear from the vegetation at different elevations. These observations suggest that factors other than elevation alone may be important in determining plant distribution. Moreover, I noticed a general trend for the leaf area of a given tree species to be lower at the lower distribution limits than in the mid-range elevation for that tree species.
Yet one more thing continues to puzzle me. As I hike over Guardman's Pass and make my way onto the east side of the Wasatch Mountains towards my home in Wanship, I notice that the relationships between tree distribution and elevation are slightly but consistently different. I will leave it for a future date to figure out this oddity. I know that there must a good explanation, because my cousin Wilford always says that there are strong relationships between climate and plant distribution.
I recorded observations of plant distributions for a few key species in Big Cottonwood Canyon below.
One strange but consistent observation that I have made is that the elevation at which a tree species first occurs on the south-facing slope is not the same as where that tree species first appears on the north-facing slope. Similarly, at the upper distribution limits, the trees disappear from the vegetation at different elevations. These observations suggest that factors other than elevation alone may be important in determining plant distribution. Moreover, I noticed a general trend for the leaf area of a given tree species to be lower at the lower distribution limits than in the mid-range elevation for that tree species.
Yet one more thing continues to puzzle me. As I hike over Guardman's Pass and make my way onto the east side of the Wasatch Mountains towards my home in Wanship, I notice that the relationships between tree distribution and elevation are slightly but consistently different. I will leave it for a future date to figure out this oddity. I know that there must a good explanation, because my cousin Wilford always says that there are strong relationships between climate and plant distribution.
I recorded observations of plant distributions for a few key species in Big Cottonwood Canyon below.
|
Species
Abies concolor
Abies lasiocarpa Pseudotsuga menziesii |
Lower distribution limit (m) on north-facing slope
1,685
2,050 1,870 |
Lower distribution limit (m) on south-facing slope
1,875
2,250 2,130 |
Upper distribution limit (m) on north-facing slope
2,220
no upper limit in canyon 2,195 |
Upper distribution limit (m) on south-facing slope
2,450
no upper limit in canyon 2,460 |
