Data and Exploratory Data Analysis
Data
Data for budbreak for both objectives came from measurements of budbreak stage from the collected branches. Curve fitting was performed using the raw budbreak data to determine the amount of heating required to reach the different budbreak stages of white spruce (Figure 1). These data were combined with several climatic variables obtained for the provenance of origin from ClimateNA for the final analysis (Wang et al., 2016).
Exploratory Data Analysis
Scatterplots were constructed for all potential predictor variables for heating requirements. Five of the scatterplots for the variables with the highest correlation with the curve fit growing degree days (gdd) above 0°C. Several other variables were explored including frost risk and mean annual temperature. Spring Frost Period (when measured in growing degree days above 0°C) has the highest correlation with heating requirements of all variables examined.