Bois De Boulogne & Urban Forest Soils

The Bois de Boulogne (8.5 Km²) is a remnant (in heritage terms only) of the Forêt de Rouvray  and the closest expanse of woodland to the centre of Paris, thus easily accessible to its inhabitants – which has resulted in some Forest usage of a seedier nature and a reputation as an area for prostitution.

Indeed the cultural ongoing history of the Bois de Boulogne is not for children. And it has had an effect on the wood, as with many other historical urban ‘green spaces’ in Europe which have a real and present damaging effect on soils – lessening their capability to effectively ‘work’ as many believe they continue to do in the same manner as our rural soils for our benefit as well as biodiversity.

For want of a better word, the soils of the Bois are ‘crusted’ – panned by consolidation by humans and their domestic pets, their excretions and their leisure pursuits.

Bizarrely, a policy taken following the great storm of 1999 which saw a huge amount of the trees in the Bois de Boulogne and elsewhere in France fall, where the chance to re introduce substantial dead wood and the natural mechanics of a woodland process by leaving many windblown trees and debris in situ, had an opposite effect. The soils where already panned and thus the layering of a significant quantity of ‘natural’ waste created a sub surface pan. Localised flooding and soil erosion started to occur, worsening year on year.

The Bois de Boulogne should be classified as ‘Technosol’ (as any garden soil or tree pit near it’s boundary would be), or at least as an anthropogenic soil. It has been far too much affected by human activity – as can be seen in many supposed semi natural woodland in the UK also. The beautiful deep alluvial soil beneath the consolidated layers was and remains largely void of the organisms which make it suitable for natural regenerative growth. And the first solution when this problem was identified was to grow deep rooted trees, which only further contributed to a false and undesirable soil. The vast majority (indeed all trees studied) have excessively shallow root plates, including those which survived the 1999 storm.

The birds that exist here do so largely due to the fruit of flowering non native shrubs in neighbouring gardens and municipal beds or even simply down to the amount of crumbs left behind from eating a picnic croissant.

The lack of decent research on the wood, its ecosystem and amenity values, are supplemented by practitioners commentary and reports working on the spot. This holds no scientific or academic credence as throughout its’ history coinciding with humankind, but maybe and hopefully will one day be properly researched.

On investigation and digging beyond the 1999 layers, there is clear evidence of processes taken by our forbears in some areas to preserve and maintain the soils and therefore the trees. Simply by uncovering and mimicking and introducing a similar system elsewhere of what was done previously was an instant solution in rejuvenating the wonderful alluvial soil found in the Bois and within a stupidly short period of time, (less than 10 days), the benefits were evident.

What we need is more woodland archaeology. Not archaeology found within woodland, but the archaeology of the woodland itself. The study of traditional silvicultural practices, because our forbear practitioners knew what they were doing – the assumption often made that our peasant land labourers were a bit dim is a dangerous one – and the vast majority of our ancient and venerable trees and woodlands exist to this day because of their knowledge and skills.

France is doing all it can, as with other many other European countries,  ( http://www.probos.nl/index.php , http://www.aisf.it/) to find a solution to modern problems by looking at this heritage and the skills and knowledge found within the rapidly depleting stock of those with traditional knowledge, England continues to languish behind other neighbouring states and worse, prepared to allow the Woodland Trust to send out PR on Agroforestry as a solution to water issues for modern farms, (which is an immensely complicated issue and one not to be considered as a quickfix solution – and certainly not touted in a manner to insult our land custodians), or Respublica to start to hone in on heritage (!?!). In doing so furthering a rapid progression towards a situation when the expert voices both academic and on the ground simply no longer exist at all.

Forget the glossy PDFs / PR and get out there with a spade and a meeting with a local landscaper / forester / gardener or allotmenteers, before trying to begin to tell others what they have long since surpassed in their knowledge. 

1 Comment

Filed under Trees and Woodlands

One response to “Bois De Boulogne & Urban Forest Soils

  1. Antony Croft

    I have seen hydrologist surveys done on some very similar sites mentioned here. This soil type/situation is a common theme in our big city green spaces, they are a draw for obvious reasons, everyone loves to go to the park. However as this post hints to, this intense activity and lack of attention to the preservation of this valuable resource is very evident. There are so many reasons for protecting soils from this intense interaction or at the very least ensuring that the effects are countered by good management. This post tries to gently introduce the reader to a very desperate need to start putting something back into these green islands that have profound benefits to the communities that live near them and interact with them. Proven benefits, from climate regulation/buffering to positive mental health benefits, the list of the pros of trees in the urban context are endless, the negatives of little note. It is remarkable that our cities green spaces all over Europe are so neglected and abused, the problem is that the abuse is not that obvious to the untrained eye, and anyone who has the eye and is willing to stand up and shout about the problem is just seen as a tree hugger.

    We need to keep shouting, and louder, our green spaces are under enough threats from development without all the other issues hinted at herein.

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