UWP - Geography - Joy Wolf

Home

Curriculum and Research Vita

Courses

Geography Home

Mixed Conifer Fire, North Rim, Grand Canyon National Park, Arizona

In this research, I used dendrochronology techniques with samples from fire scarred trees to determine a fire history in the North Rim of the Grand Canyon. My field research was conducted in the middle elevation old-growth mixed-conifer forest. This research investigates ecological processes and its response to cultural and natural disturbance. The study site ranges from the lower elevation ecotone (2200m - 2500m) of a forest dominated by ponderosa pine (Pinus ponderosa) to a middle ecotone (2500m - 2700m) dominated jointly by ponderosa and white fir (Abies concolor), to an upper elevation ecotone (2700m - 2830m) of Englemann spruce (Picea engelmanni), Douglas-fir (Pseudotsuga mensiesii), subalpine fir, white fir and ponderosa pine. I determine the master chronology for the lower, middle and upper ecotones and discuss succession patterns of invading white fir, which are shade tolerant in order to crossdate tree rings from dead trees with fire scars to construct a fire history.

Here I am in the North Rim old-growth forest. Notice the wedge taken from this dead tree.	The montane forest in the north rim have been subjected to fire suppression, consequently they are more dense with more young ponderosa pine. Since aspen trees are adapted to regenerating after fire, less young aspens are found in these forests.
I counted the annual rings from these two fire-scarred wedges. The upper sample is much older (about 600 years old!), but the larger lower sample is younger (about 300 years). The lower sample was living in more favorable conditions, so the rings are wider.	Here's what I call the 'trophy'. This sample is half the tree's diameter!