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Snow depth differences at 10,080 ft. under Limber Pine, Engelmann Spruce, and Aspen trees. By Ryan Zubizarreta. Winter Ecology, 2010 Mountain Research Station, University of Colorado, Boulder EBIO 4100, Sec 570. Question.
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Snow depth differences at 10,080 ft. under Limber Pine, Engelmann Spruce, and Aspen trees By Ryan Zubizarreta • Winter Ecology, 2010 Mountain Research Station, University of Colorado, Boulder EBIO 4100, Sec 570
Question • Which tree species allows snow accumulation to fall through the canopy more efficiently and which species holds snow accumulation more effectively in the canopy?
Location MRS
HypothesisThere will be a significant difference at the .05 level that Engelmann Spruce will have a shallower snow pack underneath the canopy than the limber pine, therefore representing that more snow is caught in the canopy of the spruce compared to the pine.
Methods • Measure snow depth using snow probe • Due north of trunk at snow pack level • .5 m and 1m • All tree’s at least 4.5m above snow pack to ensure full grown canopy • All trees in same stand at a SSE aspect and moderate slope to ensure all trees have same amount of precipitation, limiting nutrients, wind exposure and solar exposure. (Same ecotone)
Means N=27 Spruce 72.74cm 77.37cm Pine 64.81cm 76.25cm Aspen(control) 115.14cm 129.81cm .5m 1m
T-test results for distance of one species • Spruce Pine Aspen .976 .644 .735 -4.68 -4.24 -1.58 1.71 1.71 1.71 Reject! Reject! Reject! ( 3.89E-05 0.000122 0.062157 Why so close? Pearsons correlation (r) T-Stat T-crit one tail Accetp or reject? P value 1-tail (confirm)
ANOVA results between three species • Can reject null for species effect P-value=1.27E-24 Distance not dependent upon species • Can reject null for Distance effect P-value=0.033675 Distance not dependent upon distance effect • Can not reject null for interaction P-value=0.675718 Same amount of snow under canopy of Pine and Spruce
ANOVA between Limber Pine and Engelmann Spruce. • Can not reject due to species (no significant difference between species) P-value= 0.252533 • Can reject due to distance (significant difference due to distance) P-value= 0.043222 • Can not reject due to interaction effect (not dependent between species) • P-value=0.387572
Discussion • What might be some reasoning for snow falling through canopies? • How did the snow get there? • Abiotic(or biotic) factors that may of skewed the data? • What if snow evaporates or subliminates off of tree? (Montesi 2004)
Conclusion • Distance not dependent upon species • There is not a significant difference in the amount of snow under the canopies of Engelmann Spruce and Limber Pine. There is however a significant difference between Aspen(due to being deciduous and not having a winter canopy ).
Bibliography • Montesi. “Sublimation of Intercepted Snow within a Subalpine Forest Canopy at Two Elevations.” American Meteorological Society (2004): pp.763-773 • Franklin. “Tree Death as an Ecological Process.” Bioscience. Vol 37 no. 8. (1987): pp.550-556