SCIENCE / PRIMARY

Lavender and south-leaning trees: Provence


11 NOVEMBER 2021

Provence is a historical province in southeastern France. It has a Mediterranean climate, characterised by hot and dry summers and mild winters. This climate is a result of the strong Mistral winds that help to blow away clouds and storms that may linger over Provence. The Mistral winds blow in a southward direction, originating from the north. The winds have a sustained speed of often more than 66 km/h, sometimes reaching as high as 185 km/h. 



The Mistral blows when regions of high pressure form in the north and regions of low pressure form in the south. While it blows most frequently in the spring and winter seasons, it can occur in all seasons. Entrances of farmhouses in Provence are thus built with entrances facing the south to prevent unnecessary inconvenience for residents when the Mistral blows. 


The winds of the Mistral accelerate when they pass through the Rhone Valley. The Rhone Valley constricts the flow of the Mistral and this causes the speed of the winds to increase. This is simply explained by conservation of mass, A v = constant.


When the cross-sectional area, A, of the wind is decreased, the velocity, v, of the wind would increase so as to ensure a constant mass flow rate. 



These strong winds even affect the growth of trees and other plants in the Rhone valley, causing them to lean towards the south!


The beauty and perfume brand, L’Occitane En Provence, also has its roots in Provence. In fact, the name means “the Occitan woman in Provence”. One of the ingredients used in the making of their perfumes is the lavender grown in Provence. 



Lavender needs at least 6 to 8 hours of sunlight daily and also prefers moderately dry climates, with mild winters and sunny summers. Thus, Provence provides the optimal growing conditions for lavender. Next time you walk past a L’Occitane En Provence store, think of Provence and the wonders of the Mistral.




TAN YONG BOON

Author