Phenology and senesence observations of two balsam poplars in different locations with varying amounts of sunlight on UW campus

-- Balke Balzan, Shelby Baumgartner, Taylor Miller, Lee Noel, Luke Nieslanik

Many trees have adapted to tolerate cold, harsh conditions. Balsam poplar (Populus balsamifera) trees are no exception and have also developed mechanisms for surviving unfavorable circumstances, such as losing leaves in the fall season. Three random leaves were selected from two Balsam poplar trees five to seven times a week. One tree was located in a high sun exposure area and the other tree was located in a shaded area. A spectrometer was used to measure leaf reflectance values.

Normalized Difference Vegetation Index (NDVI) was calculated to observe a trend in each tree over time. Our group hypothesized that the tree with more sun exposure would keep its leaves longer into the fall season. However, results did not support this hypothesis. Both trees had very similar NDVI values throughout the course of the study. According to this experiment sun exposure is not a noticeable limiting factor in Balsam poplar senescence.