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?

Pinus flexilis

Picea engelmannii

Populus tremuloides

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 Spruce72.74cm

77.37cm

Pine64.81cm

76.25cm

Aspen(control)115.14cm

129.81cm

.5m

1m

T-test results for distance of one speciesSpruce Pine Aspen

.976 .644 .735

-4.68 -4.24 -1.581.71 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 value1-tail (confirm)

ANOVA results between three species

Can reject null for species effectP-value=1.27E-24 Distance not dependent upon species

Can reject null for Distance effectP-value=0.033675 Distance not dependent upon distance effect

Can not reject null for interactionP-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

Results and Analysis

1 2 30

20406080

100120140

Distance Effect btw species

.5M1M

Tree species

Snow

dep

th (

cm)

Spruce Pine Aspen

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 ).

BibliographyMontesi. “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