When Will Douglas-fir Flower?

The Douglas-fir reproductive budburst tool highlights how both cool (chilling) and warm (forcing) temperatures influence the date of flowering for Douglas-fir. This website uses real-time data from NOAA weather stations to update graphs of winter temperature accumulations so users can see when the accumulated values are nearing those that enable flowering. The tool uses equations adapted from a reproductive phenology model and daily temperatures from NOAA to estimate chilling (cold) and forcing (warm) temperature accumulations from November 1st through today.

Click on a red balloon see a current graph of chilling and forcing accumulations from November 1st through today. When the blue line tracking temperature accumulations gets close to the orange possibility line – it should be time for Douglas-fir to flower!

Note: it may take a while to download the weather data - be patient.

Going farther: If you would like to use hourly temperature data from your own weather station to predict the timing of reproductive budburst - download our excel workbook here: download

Information on the parameterization of the model used for these calculations can be found here.

Prevéy, J.S., Harrington, C.A. and Clair, J.B.S., 2018. The timing of flowering in Douglas-fir is determined by cool-season temperatures and genetic variation. Forest Ecology and Management, 409, pp.729-739.