1. The effect of tree density and height on tree-flagging of Lodgepole Pines in Niwot’s sub-alpine forest Michael D. Schuster Winter Ecology – Spring 2010 Mountain Research Station – University of Colorado, Boulder

2. Mechanisms of tree flagging Predominately carried out by wind Krummholz: “Crooked Wood” in German; These are the type of trees/shrubs near or at treeline Reasons for bareness of trunk: lack of SR

3. In the Big Picture Why is this important? Useful for forestry practices Can put in context of CC scenario Affects passage of mammals

4. Observations and Hypothesis I noticed that the trees had varying heights of bare trunk and branches, and this general height changed when the trees were either taller or closer together Hypothesis: affected by amount of sun reaching lower branches, not by krummholz or wind as much – As the avg height increases, the height of the bare tree will also increase – As the L.P. Pine density increases, the height of bare tree should also increase (more trees-more coverage-less sun to ground)

5. Methods 10x10 m transect Clinometer, field tape, flags, snow probe Total density, density of conifers Avg height (clinometer), snow depth

8. P-value = 0.0128 Site #P value 10.366941 20.037538 30.067436 40.00619 50.010393 60.762244

9. Conclusions Total L.P. Pine height increases with elevation Bare trunk height is variable—other factors Density increases with elevation % of bare trunk increases with increase in total height No significant results—other variables are affecting the outcome

10. Other variables to consider – Slope of transect – Aspect of transect (tried to keep this constant) – Elevation – Type of forest (are there deciduous trees) – Amount of exposure (wind – Snow depth (how does this affect height of bare tree) – Inaccuracies with measurements (10 m distance of transect, from tree, density average)

11. Suggestions for next time Bring an altimeter, measure elevation More accurate measurments of snow depth Find a better way to measure density Choose transects carefully, controlling for: – Slope, aspect, exposure, types of trees (no deciduous) Finally, for next time: BRING A CAMERA

12. Works Cited Reference articles Arno, Steven F. Timberline: Mountain and Arctic Forest Frontiers. Chp.1 excerpt, prepared by CU. New York, 2007. Pictures: – http://www.daviddarling.info/images/vegetation_flagging.gif http://www.daviddarling.info/images/vegetation_flagging.gif – http://www2.swgc.mun.ca/botany/burntisland/images/Flagging%201. jpg http://www2.swgc.mun.ca/botany/burntisland/images/Flagging%201. jpg