Author Archives: Mathias Lehner

20 ideas for integrating biodiversity

(c) Amsterdam Municipality

Biodiversity experts Anne Blokker and Geert Timmermans of the Amsterdam Municipality compiled a brochure with 20 ideas how to integrate biodiversity in urban planning and development. The insightful publication was originally published in Dutch, but is now also available online in English.

From nesting bricks for birds, over green roofs and eco-friendly banks up to an interconnected ecological structure these richly illustrated 26 pages make it easy to explain the benefits, and paths of action to clients, spatial designers and colleagues.

The publication is freely available on issue.

Symposium: Climate resilient, green and nature inclusive city

On September 24, 2021 Biotope City Foundation Amsterdam/Vienna and the Viennese BOKU University for Natural Resources and Life Sciences this September organize an online symposium on the nature inclusive future of our cities.

The topics addressed will include the freshly realized Biotope City in Vienna, the Floating University Berlin and 10 sessions on top climate resilient strategies (such as sponge cities, participation, green cover effects, climate trees and urban farming), concluded by lessons learned for the future.

Speakers include Helga Fassbinder, Jeanne Astrup-Chauvaux next to Bernhard Scharf (Green4cities), Angelique Bellemakers (INBO architects) Marlies Zuidam (FAAM architects), Maria Auböck (Atelier Auböck+Karasz), Brenda Swinkels, van den Berg Nurseries, Tim Elfring (Phood Kitchen), Steven Delva (Delva Landscape Architecture Urbanism), Pia Minixhofer & Sebastian Hafner (BOKU), Florian Kraus (Greenpass) and Florian Reinwald, (Institute of Landscape Planning ILAP).

Moderator: Mathias Lehner, research director nextcity.nl and strategic advisor urban development Zaanstad Municipality

Date: 24th September 2021
Time: 9:00 – 13:00 hrs, online
More info and program in English and German here.

If you want to join, please register with an email to contact@biotope-city.net.

The symposium via Zoom can be accessed here. Meeting-ID 914 3531 0298,code 918728.

Keep the distance – to city trees!

When it comes to value creation ‘climate’ trees (klimaatboom in Dutch) are playing on an olympic level. Financially houses are worth 8-15% more with adjacent green and trees according to brokers. Socially, people are happier in a green environment with trees. Old trees do even better: they evaporate more moisture and absorb more water (up to 500 times) than a young tree. So, how is it possible that trees often die young, whereas an old tree is much more valuable?

In cities, lack of expertise on how to lay out and dig for underground cables and pipes is a frequent reason for ermanent damage. Digging within 6 meters of a tree of 1 meter diameter or within 2 meters of a tree up to 30 cm diameter impacts the tree’s roots.Today, trees are sometimes placed on top of a cable and pipe or the cable is laid underneath. When the cable is replaced (once every 25 years) tree roots are severely damaged, and with fungal ingrowth, the tree dies a few years later. Ideally cables and pipes are at least 2 meters from trees if we want to get trees big and old. So, we can do better, can’t we?

In the past small trees were also planted on two sides in the sidewalk of narrow streets. With reduced fitness and less space for roots, growing old is a major achievement for a tree then! Today, often more space is reserved for trees, both above and underground, in order to have trees that age sustainably. A tree squeezed in between the pavement does not have a long life. 9 m3 of rootable space above the groundwater level is required for a small tree up to 6 meters in height. Want a large tree of more than 24 meters in height? You’ll need at least 65 m3 of rootable space. It’s no wonder that tree roots push up pavement when there is no space and moisture, while they are searching for nutrients.

So, keep the distance and give city trees the space they deserve, and let us humans enjoy the values created and the full range of ecosystem services to adapt to climate change.

This post is based on a memo by Frans Lubbers, maintenance specialist water and green @Zaanstad Municipality accompanied by an article by Bart Mullink in Boomzorg 3/2021.

How health and well-being in pandemic times relate to the use public outdoor space


Organized by Wageningen University assistant professor Agnes Patuano the symposium ‘Public Outdoor Spaces and Covid-19’ held on 24th and 25th of June, 2021 addressed the question “How will the COVID 19 pandemic impact the use and design of public spaces, and how was it impacted by them in the first place?”

The symposium brought together recent research from WUR, HvA, BOKU, Radboud University, Marie Curie University, University of Milan, Aeres University and Universidad Nacional Agraria La Molina.

Mathias Lehner contributed with a talk on his approach and research on nature-inclusive public space, with a focus on reclaiming ‘car-space’ in cities, in order to redesign integral blue-green-grey networks that boost quality of public space, while contributing to human health and well-being. Read the summary here.



Hidden treasures for a sustainable city – Biotope City Vienna

(c) image: Bauplatz 3 (ÖSW/Rüdiger Lainer + Partner) Visualisierung: Schreiner, Kastler

Praised by the advisory board of IBA_Wien because of “the consistent approach of a multi-layered implementation of contributions to climate adaptation in new neighborhoods” and the “scientific support for neighborhood development in connection with climate-relevant contributions” the new Biotope City Wienerberg urban quarter is an interesting and very recent urban development to study in more detail.

Biotope City Wienerberg will be presented as part of IBA_Wien in 2022 on an international level as an innovative model example for future solutions in connection with adaptation to climate change in urban areas. The project contains many qualities that are not immediately visible upon completion at the end of 2020. But already now, IBA Vienna has published the brochure “Hidden Treasures“, which describes the hidden treasures of this forward-looking district.

Published by: IBA_Wien 2022 – Neues soziales Wohnen
Content and editors: Knollconsult Umweltplanung ZT GmbH Prof. Dipl.-Ing.in Dr. Helga Fassbinder Institut für Landschaftsplanung, BOKU Wien Articles by: Stiftung Biotope City Green4Cities GmbH, DI Thomas Romm, forschen planen bauen, ZT Lehner Real Consulting GmbH, Stadtteilarbeit Caritas der Erzdiözese Wien
Graphics and layout: Knoll Kommunikation GmbH

Housing quarters rich in nature – learning from experiences

Cover brochue (c) KAN

Building with nature requires a different way of working from developers, construction parties and housing corporations. This include new knowledge, a different perspective and a different role in the process. The study ‘Learning from natural residential areas from the past’ has come up with concrete tools for the development process, design, implementation, management and communication. These are now briefly summarized in the digital brochure which can be downloaded for free at KAN (Climate Adaptive Network Netherlands).

Green as Building Material Conference

On May 26-27 2021 the ‘Green as Building Material conference on ecological and nature inclusive design of the climate resilient city ist organized by Delft University of Technology.

The aim of the conference is to investigate and discuss the value of implementation of Nature in the built environment. Nature offers a range of specific ecosystem services. Two examples of such services are provided by vegetation in form of mitigation of heat stress in cities through provision of shadow and evaporation of water, and retention of water during intense rain showers reducing risk of flooding. Ecosystem services can play an important role in designing current and future climate-proof cities. In addition to aforementioned city cooling and water retention, many more useful ecosystem services can be provided by Nature. Further examples are cleaning of air, water and soil, and strengthening of biodiversity in the urban environment. Nature-inclusive cities are therefore healthier, more attractive, and thus overall more liveable.

On May 27 Mathias will speak about his research and findings within his vision of the ‘Next City’ as a biodiverse and nature-inclusive city of the future. The lecture is part of the session on design consequences of integral nature-inclusvie building.

Manifesto: Right upon Green Environment

Right on time for lobbying towards the municipal elections in the beginning of 2022 the Dutch nature and garden associations presented a Manifesto on the Right Upon a Green Environment at the end of March 2021 which stresses the benefits of a green environment and implicitly nature-inclusive cities.

The Manifesto is based upon recent research on the European Green Captials published in 2017: Well established and maintained green areas have a key role on reaching the high quality of life […] Green Capitals are leading cities (chronologically, Stockholm, Hamburg, Vitoria-Gasteiz, Nantes, Copenhagen, Bristol, Ljubljana, Essen and Nijmegen) that provide an excellent access to the public green areas . […] As a result of abundant provision and proper distribution, almost all citizens in most of the Green Capitals live within a distance of 300 meters to a green area.

This manifesto is even more urgent today as the one-year-anniversary of covid-19 in the Netherlands has shown a significant increase of burn-out among employees (research by CNV union) that even worries national health insurances (article by Zilveren Kruis).

The manifesto was initated by AVVN , Natuurlijk tuinieren, KMTP/Groei&Bloei, KNNV, NL Greenlabel, Stichting Steenbreek, Velt and Vogelbescherming Nederland.

Metropole Ecology Course

In spring 2021 the Master on Earth Sciences Future Planet Ecosystem Science at the University of Amsterdam and its course ‘Metropole Ecology’ held by Prof. Judy Shamoun-Baranes, Dre Verena Seufert (VU).
An increasing part of Earth’s terrestrial surface is taken up by urban and peri-urban land use, forming large agglomerates known as metropoles. These intensively-used areas are dynamic ecosystems with distinct properties, hosting particular species and communities, but also creating nuisances e.g. through invasive species or human-wildlife conflicts. At the same time, metropolitan ecosystems are pivotal in supporting human well-being, as over half of the global human population lives in cities, facing challenges related to e.g. air quality, heat, storm water, and space for leisure. Urban ecosystems can provide services to address some of these challenges. In this course we use an interdisciplinary approach to understand specific challenges and opportunities of an urbanizing world for biodiversity, ecosystem functioning, and people. Specifically, we will learn about biodiversity, human-wildlife interactions, urbanization, human well-being, and the role of ecosystems and their services in addressing these challenges”

On Monday April 12, Mathias will speak on Nature inclusive building: Dive into the Anthropocene and find out how the rapid growth of metropoles is not only a threat but also an opportunity to bundle forces and design a new generation of cities based upon the hypothesis of the Next City that provides Quality of Life – for all Species.

How to combat climate change & its impact as architects?

The Royal Institute of Dutch Architects BNA is offering the Course on Circular Designing and Building, including a session on Designing Nature-inclusive and Climate-adaptive. This session on April 13 2021 addresses biodiversity, quality of life for plants and animals, building with green as well as dealing with the influence of heats, droughts and heavy rain. 

Next to Mathias explaining on how to contribute to UN SDG 13 “Take urgent action to combat climate change and its impacts” and how to think in systems and processes from a spatial point the co-speaker in this session will be Robbert Snep (WUR).