Historical research helps biodiversity in Leiden city centre
The Leiden municipality wants to make the city centre climate-proof and combat heat stress by greening it. But they want to do this in a way that does justice to the city’s heritage. Researcher Fenna IJtsma delves into historical greenery to offer inspiration.
‘'The municipality wants more greenery, but also wants to preserve the protected cityscape,' explains IJtsma. 'To ensure that this becomes a whole that merges with the city, the municipality started the Leiden Heritage Deal project in collaboration with knowledge institutes and city partners. Part of this is historical research into the greenery and quays within the canals to build on. Where were there green areas, and how was the land used?'
Interdisciplinary approach
For this, IJtsma, together with Ariadne Schmidt, is working with heritage experts from local heritage organisation Erfgoed Leiden en Omstreken and biologists from Naturalis. 'While I am looking at history, the biologists and researchers from Naturalis are starting a biodiversity study,' she says. 'That interdisciplinary nature makes this type of research very innovative.'
At the first meeting, this different outlook was immediately apparent. 'On the visual material I presented, I only saw trees and some grass. They immediately started talking about gradients in the landscape and their importance for biodiversity.'
Four centuries of material
In total, IJtsma has four centuries of archive material at her disposal, full of inspection books with regulations, the workings of the city council, for example on the construction of the Plantsoen or the archive of the Leiden Health Committee. She can also make use of material constructed later , such as statistics on population growth. 'If a city's population shrinks, houses might be demolished, which could in turn provide more space for greenery.'
It will therefore not be possible to map all the material in the year that is available for this study. To select the most appropriate material, I really want to rely on the municipality's urban designers,' explains IJtsma. 'What do they focus on? What do they think they can do something with? Based on their comments, I can steer the research in the direction that is convenient for them.'
No 1:1 Reconstruction
It is emphatically not IJtsma’s intention to restore the historical situation exactly. 'If I find elms somewhere, there’s no absolute need to replace them,' says IJtsma. 'It can, however, be an inspiration to consider what trees or other types of greenery would do with that spot.'
In addition, historical documents can offer arguments. 'A large part of the city centre is historical townscape, so the possibilities for greening are a bit more limited: you can’t always just plant a tree in front of a monument. In cases like that, it can help to know what the green area once looked like.'
Occupant toolkit
One special aspect of her study is that IJtsma will also reach out to residents with her research. 'Besides a toolkit for the municipality to make public spaces greener, there will also be a toolkit for residents. They can use it themselves to make their gardens more sustainable.'