Populus tremuloides vigor in comparison to daily high and low temperatures

-- Jennifer Bayne, Clint Beiermann, Alicia Brown, Spencer Northup, Preston Talbert

The weather that accompanies the fall season in Wyoming tends to be highly variable; extreme temperature fluctuations and snowstorms are not out of the ordinary beginning in September. The vegetation and plant life in the area begin the process of dormancy once the temperature begins to drop. Presence of temperature fluctuation between September and November cause an uncertainty as to when the leaves will begin to change and eventually fall; whether it is early in fall or later.

We selected an aspen tee approximately 30 yards south of the UW Agriculture building (figure above). Leaf samples were collected twice a week at 1:10 pm starting on September 11th and ending on November 6th, 2014.

We measured the spectral reflectance of the leaves and calculation the normalized difference vegetation index (NDVI) and recorded the minimum and maximum temperatures for that day. Our results showed a direct correlation between daily low temperatures and NDVI values.