Lodgepole Pine Cone Density

By: Corey SlinkardEBIO 4100Spring Semester 2012

Outline Hypothesis About the Lodgepole Pine

Location Importance Reproduction Cones

Methods Results Discussion Citations

Hypothesis

Due to the strong westerly winds on Colorado’s Rocky Mountains, I hypothesize cone density on Lodgepole Pines will vary by hill slope direction, particularly on east-facing slopes in areas around MRS. Relates to winter ecology

because the LP has ~26 monthpollen-cone and seen-cone bud Initiation… (Owens, 2006)

More on Lodgepole Pine

Location: Pinus contorta extends

from the Mackenzie district of the Yukon in Canada, to southern Colorado in the Rocky Mountains and northern Baja (Owens, 2006)

Lodge Pole pines are important because they account for about 7% of Rocky Mountain forests.

Distribution map:Pinus contorta subsp. contortaPinus contorta subsp. latifoliaPinus contorta subsp. murrayana

Lodgepole Importance

• Ecological • Protective cover for watersheds • Wildlife Habitat •Aesthetic value for recreationEconomic Importance

Valuable source of timber products One of the most extensively harvested trees in

west.

Points on Lodgepole Reproduction

Reproduction The cones are serotinous

“Serotinous cones do not open at maturity, but remain closed until the resin bond between cone scales is melted.” (Knapp and Anderson, 1980)

It is a fire adapted tree Lodgepole pines have fairly thin bark, which reduces their

defenses against fires. Tend to outcompete each other for resources, often

leaving many of them to dry up and die. These dead Lodgepoles then become a fuel source for a

future fire, increasing the heat needed for reproduction.

Cones

Opening the fire adapted cone Temperatures ranging from 40-69º C have been

reported as sufficient to open the cones. (104º-156ºF)

Seeds inside the cones DO NOT lose viability with age!

“Although direct sunlight can, in some circumstances, open the cones, fire normally releases the seeds to the favorable seedbeds.” (Knapp and Anderson, 1980)

Methods Location: Surrounding areas of MRS 3.0m x 3.0m area How much shade? Count number of Lodgepole Pines Direction hill slope faces

South North East Flat

Approximate tree height Count number of cones on each tree

Total number Use binoculars

Results

East East North North South South Flat Flat0

102030405060708090

Avg. number Cones vs. Slope-face

EastNorthSouthFlat

Slope-facing Direction

AverageNumberCones

Avg. cones East: 16.14North: 17.21South: 49.08*Flat: 15.38

*contained outlier

South-face slope? •What’s going on here?

Other Results

Seems to be no correlation between slope-face direction and cone density…

Light Moderate Extreme13

13.514

14.515

15.516

16.517

17.5

Shade vs. Average cones

Amount of Shade

Averagenumberof cones

• Relationship?

•”Lodgepoles are quick to occupy a site… full of sunlight”(Owens, 2006)•Does contain outlier

Discussion

HYPOTHESIS FAILED?Why?

Cones only need to get to a certain temperature to release seeds. If ground is on fire, wind direction might not make

a difference. Remember: cones remain closed until the resin

bond between cone scales is melted. (Knapp and Anderson, 1980)

Relationship between shade and cones? Maybe… Future projects.

Citations A.K. Knapp and J.E. Anderson. “Effect of Heat on Germination of Seeds from

Serotinous Lodgepole Pine Cones.” American Midland Naturalist , Vol. 104, No. 2 (Oct., 1980), pp. 370-372

Owens, J. "The Reproductive Biology of the Lodgepole Pine." Forest Genetics Council of British Columbia. (2006): 1-62. Print.