While many of the iconic roads used at the Spring Classics are the same as editions past, researchers coincidently realized one thing wasn’t the same along these famous roads as editions in previous decades. Television footage reveals changes in the timing of the blooming of trees that line the roads of Belgian in the famous spring one-day races.
Pieter De Frenne is a cyclist and scientist who studies climate change and botany at Ghent University’s faculty of bioscience engineering. In 2015, he was watching archival footage of the 1980 edition of Liège–Bastogne–Liège and noticed the weather looked a lot colder and the trees didn’t have flowers or leaves.
De Frenne went and found footage from Ronde van Vlaanderen which is always held in early April thinking researchers might be able to use footage from one of the sports most famous races over the past decades to observe and study the tree’s response to climate change. The researchers not only wanted to plot the response to climate change but also demonstrate the usefulness of using archival footage to build datasets of phenological responses to climate change. In the recent study published in the British Ecological Society’s journal Methods in Ecology and Evolution, the researchers outlined their work.
After reviewing over 200 hours of footage, the researchers were able to make over 500 observations of 46 trees that line the route of the Tour of Flanders. While the course had changed over the years, organizers use iconic sections of cobbled climbs in every edition like the Paterberg, Koppenberg and Oude Kwaremont. On 12 climbs, they were able to identify trees that appeared in the footage of each edition of the race. The researchers also looked at the most detailed climate information for the region available. Eight temperature and precipitation metrics were used that have been shown to be very accurate to predict flowering.
Since 1980, the temperature on the 12 analyzed climbs had risen by 1.5 C and the foliage and flowering patersn correspond with the climate data. The researchers observed that in the 1980s, there was virtually no foliage or flowering on the trees that line the course. Since the 1990s, more trees had begun to grow leaves and started flowering. In fact, between 2006 and 2016 nearly 45 per cent of the trees had begun to grow leaves compared to only 26 per cent between 1981 and 1990. Temperature and accumulated heat the researchers say explains this trend.