NATURAL PLAYGROUND: RAW NATURE

RAW NATURE: NATURAL PLAYGROUND Parc Natural de la Serra de Collserola // MAEBB - IAAC

THE SITE

EL Mirador de Collserola Park is a very central location for adventure and nature lovers, with breathtaking views of the city and the mountains. It is located at the end of tree hiking paths, and some excellent route for road and mountain bikers. We aimed with the natural structure to bring more families and kids to this beautiful place to reconnect with nature and take a break away from the city.

SITE

Parc Natural de la Serra de Collserola has a long-term forest management plan to reduce the amount of biomass in the park as a way of preventing fires and increasing the amount of biodiversity and the health of the forest. If biomass is reduced strategically in Valldaura, there is less risk of fires and gives other species the opportunity to thrive in the forest and a greater biodiversity of flora, which in turn increases the biodiversity of fauna.

The team learned about responsible forest management in order to select trees gradually meet the 40% reduction of biomass that the park requires. The team decided to cut pines as these are a colonizing species that have long out-competed other species in the forest, considering it essential to increase the biodiversity in the park.

The criteria for choosing the trees was their structural stability and branching aesthetics to provide more opportunity to create movements across the structure. This assisted us in choosing four trees out of which three were used for the final structure.

PHOTOGRAMMETRY // DESIGN

Once we had the trees chosen, the next step was to digitally scan the trees using low-tech methods to extract a 3D model to create an accurate approximation for the purpose of designing the playground.

For this purpose close to a hundred photos were taken of each tree from all possible angles from the ground before cutting and then horizontally after tree felling. To create the scans we used a software called Agisoft Metashape that performs photogrammetric processing of digital images and generates 3D spatial data from which a close approximation mesh was generated for the trees. Further refining with was done on 3D softwares to get a usable model for the design process.

Once the photogrammetry was complete we proceeded to design a structure with trees laid out horizontally and vertically making use of their natural structural shape to form the design. By forming an interlocking layout of trees we create a space for climbing ropes while the rest of the structure becomes a natural climbing structure assisted by ropes winding around branches.

JOINERY

Dealing and trying to connect natural wood is not an easy task because the wood is not tested to know what and how it is inside. We had to be as precise and careful dealing and testing ways to make successful joints. Finally we managed to come up with a great way of dealing with the natural wood and succeeded in applying safe and strong joints.

The joints request few steps in order to be assembled correctly. First, we started drilling down the big washer that would hold a bigger surface of the wood. Second, we took the center and we drilled the hole that the screw would go through. Third, on the other side we needed to make another space for a washer, so we could put a spacer in between both of the woods. The spacer is used to give a measured space between the two peace’s of wood for safety reasons so kids don’t get stuck. The same methods were applied to the other trees.

Transporting the whole structure to the site for preparation was quite a challenging task, which took into account not only the vehicle, but also the test assembly in the back yard and the final transportation.

Firstly, for the test assembly we used ropes, bricks and rocks to hold the trunks to ensure their position and to be able to disassemble easily. Then, for the site transportation we chose to move the vertical and large horizontal trunks first, as they still needed to be treated on-site. Finally, we transported all the small horizontal trunks to the site with help of a bobcat for the final assembly.

With the help of cranes, we transported the preprocessed tree trunks to the work site for final treatment. We continued to peel and paint some tree trunks on-site.

We first dug holes in the ground according to the size of the stone, drilled holes in the stone, placed threaded rods, and finally drilled holes in tree trunks and connected them with nuts.

We first placed the larger stones in v1 as the base, then put them into the trunk, then placed the smaller stones as further fixing, finally put the gravel to fill the gap, and used the machine to compress. So the trunks can be set upright in the pit.