2020 – Miyawaki Planting in Nanterre University

Before planting

2 years later

Planting period : december 2020

m²

plants

volontaires

Planting carried out as part of a three-way partnership, initiated by the student association LABESS: Laboratoire Éthique, Économique, Social & Solidaire, and the University of Nanterre, which financed the project (University Participatory Budget).

The LABESS association’s objective was to experiment with the Miyawaki method to recreate a “nourishing forest” using fruit-bearing plant species, for wildlife and students. Almond trees were included in the species selection, echoing Nanterre’s almond-growing tradition.

The students and the university took over maintenance of the plantation. The period of health crisis and its impact on student life posed new difficulties for this aspect.

Planting site: Nanterre University campus (92)

The plantation is located on the Université de Nanterre campus, in the allée des Arts, behind the CROUS refectory. The site was chosen after considering several options, based on data provided by the university: biodiversity inventory, differentiated management plan for campus green spaces, soil survey reports.

As the soil on the campus is largely composed of backfill excavated during the campus construction period, it was carefully assessed at the planting site itself, in order to assess the quality of the soil conditions and gain a better understanding of the high drainage capacity of the soil at this level, as emphasized by the campus green spaces field agents, who alerted us to the risk of water shortage for the trees.

GPS coordinates : 48.90485, 2.21745

The planting in pictures

Before planting: site preparation

Click on images to see the caption

Situation before planting

Knowing the history of the planting area is essential. Following discussions with the campus green space agents, we learn that the soil is very mineral, derived from earth fill dating back to the various campus constructions. We asked them to dig pits one metre deep (with a mini-excavator) to check that there were no slabs, water or electricity networks, and to assess the porosity of the soil.

The excavated pits reveal a very porous soil indeed, containing a lot of small-sized rubble residues, which don't retain water. We take this into account by adjusting the amount of compost and bark we include in the soil, to enrich it and add more organic matter.

The soil is amended with a generous amount of compost, making it much looser and richer, to a depth of around 30 cm. This depth is the minimum required to allow the tree roots to anchor easily in the first few years after planting.

Planting in December 2020

Click on images to see the caption

With the soil turned over and amended, the surface was divided by string into equal parts, which different groups would replant over the two days of planting. Dividing the area into equivalent strips facilitates organization during planting: it's easier to keep track of progress.
Photo ©Claire SERIE

Here we go!

Photo ©Claire SERIE

The trees are brought to the plot as the volunteers advance, leaving the roots of the seedlings sheltered in a gauge. The seedlings are then immersed in the praline vat, a mixture of water and soil, which stimulates and protects the roots before planting. Photo ©Claire SERIE

Example of well-praline roots: the roots are well covered with the mixture. Each plant has a different root system: you'll need to observe it carefully to dig a suitable hole and avoid compressing them.

Photo ©Claire SERIE

First day of planting: it's taking shape! In each marked-out area, groups plant and mulch, so you can see the planting taking shape as they go along.

Photo ©Claire SERIE

Second day of planting: the students are still going strong and enjoying the exercise!

We can't stress this enough: a plantation is a place where people meet and exchange ideas! The joy on people's faces is a very important indicator for both organizers and participants, in our opinion 😉

After a fairly intense rainy spell, the volunteers held out well, and when we looked back on the morning of the third day... What a joy!

Evolution over time

First summer for the young trees: in the middle of August, they are showing great vigour!

Straw placed on the ground keeps the soil moist and provides a certain guarantee that the trees will stand above any other weeds that may take hold, at least in the first year. This is essential for their recovery and growth.

2 years after planting, in summer: the herbaceous plants have finally grown, flowered and attracted a large number of pollinators, before wilting. By this time, the trees are already taller than them, and therefore less bothered by their presence.

View of the small nourishing forest, two years after planting