Abstract

ABSTRACT
The Impact of Climate Change on Two Temperate Tree Species of Maple in Urban Areas of Canada

C.-Sophie Gauvreau

The flowering responses of many trees are affected by climate change. In the long term, a species’ survival rests on its ability to produce seeds. Phenological events such as budburst or flowering are an effective variable to assess the effect of climate change, as these events are mainly controlled by temperature. This study aims to examine the effect of climate change on two anemophilous tree species with early spring pollen onset, the silver maple and the Manitoba maple, in mid-latitude Canadian cities. I used pollen season onset date and meteorological data from various urban areas in Canada to assess the impact of climate change on the timing of pollen release onset. The first part of the analysis used linear regression models and the second part used linear mixed-effect models along with different degree-day functions to estimate the effect of winter and spring temperature.
The results showed a strong correlation between mean monthly air temperature during spring and pollen season onset as well as heating degree-days accumulated during the quiescence phase of the yearly biological cycle of the two species, in March and April. This suggest that changing spring temperatures may already be having an effect on the timing of pollen onset and we may expect this to continue as temperatures continue to increase.
Keywords: Phenology – Aerobiology – Temperature – Climate Change – Pollen – Linear Regression – Mixed-Effect Models - Flowering – Canada