Pyla Dune series: beyond all expectations

The Great Dune of Pyla - photo Naomi Edwards

The Great Dune of Pyla – photo Naomi Edwards

I hope you are sitting down cause Pyla Dune was off the hook! Here we go…

It’s been a few days since I saw Pyla Dune and I’m still on cloud dune. So, I’ll try my very best to help you grasp what I’m trying to grasp as I’ve been dune stunned, beyond all my very dune expectations.

To be honest, I only recently heard about the Great Dune of Pyla as a colleague of mine at Griffith Centre for Coastal Management gave me an information booklet about the geography of the dune. Due to my up-built excitement about my first euro-trip, after reading about Pyla Dune I had to check it out! If the Eiffel Tower made it onto my itinerary, Pyla Dune had to be a must see too [and now I can say at least I climbed Pyla Dune – see City to city: London to Paris].

Simply stated, Pyla Dune is Europe’s biggest dune and it beautifully deserves such a status. Though more technically, is a unique variable dune that is part of a much larger dune corridor (for those on the east of Australia where development dominates or is yet to dominate this dune corridor would blow your mind). As the area of coastal dunes I am referring forms part of the Arachon Bay region, and the larger dune corridor extends from Gironde to Biarritz – 8km wide and 230km long. Most of the area is covered by pine forest, which forms a “green triangle” between the lakes and shoreline. Though as for Dune Pyla, it’s moving canvas of sand – being bare, variable and live.

Within the Arachon Bay region there has been 1500 dunes identified with varied heights from 30-50m to over 100m. To give you a grand concept of the grand dune, Pyla Dune is actually 2.5km long, 500m wide and just over 100m high. That is a grainy volume of 125million3 of sand or 50K Olympic-sized swimming pools or 1.79 million truck loads of sand or 2million average children-sized sandpits. This sheer volume could make anyone along an erosion hotspot jealous!

In my opinion, thank god the French got it right a long time ago and listed the dune as a national treasure as a Grand Site of National Beauty back in the 1930s.

I am sure you are starting to get the gist that Pyla Dune is no ordinary dune – though what is an ordinary dune? More so, why is it so big!

Leaving such a question for another day, the formation of Pyla Dune is just as gob smacking unbelievable. Pyla Dune is a result from an accumulation of sand being trapped within the area by westerly winds over thousands of years. At least, for the last 3500 and more years, mountainous volumes of sand have accumulated, which secondarily moves the dune towards the forest.

The dune shows an “asymmetrical morphology with steep slopes to the East and gentle slopes windward to the West”. Radiocarbon testing and other history dating analysis has identified four distinct timeframes for the geological make-up. From the base to the summit, on days where there are lesser crowds, you can actually see the make-up of such sediment contours.

  1. The base of the dune is actually stratified soils consisting of upper layer sediments and peat. These soils are over 3500 years old, known as old podzol.
  2. The second stage of the make-up is 2-5m above sea level and contains dune palesols and diatoms.
  3. To 20m, the dune composes of other vegetative remains and siliceous fresh water diatoms (most likely from a surrounding lake).
  4. From 20-40m, the morphology is similar to the upper parabolic dune zone, though many treasures have been found including old bronze coins, shell fragments and a resin furnace. Mapping completed in 1863 found the upper part (at the time it was 80m), to have once been planted by pine forest to help stablise the dune and exploit the wood for industrial use. Though to the displacement and changes in the Arachon Bay region, between the late 1800s and early 1900s, over 500m was eroded. The dune is still developing and changing…

Given the variable nature of the dune, there are distinct management practices in place to stablise the foredune zone with the objective to protect the pine forest. Long-term research has indicated that Pyla Dune moves eastward at a rate from less than a meter to over 7 meters annually. This vast sand movement literally smoothers the pine forest at the back as for once dunes seem to be winning a battle, though, in this fight the forest of the Arachon Bay is being suffocated. Such movement also coincides with the ocean front erosion and plagues the complexities of dune-coastal management.

However, the attractiveness of Pyla Dune fosters a thriving dune tourism industry, which in effect supports its management. However, the intensity of foot traffic from tourists does come at a cost for the sustainability of the dune. There are currently discussions taking place to see if tourist numbers could be capped to help with the long-term sustainability of the dune.

I could share and ponder so much more. Until next time, I’m heading to bed to dream about Pyla Dune!

PS – I’ll have to upload a photo gallery soon to share the extent of the dune tourism in place, or might as well tangent about that.

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