DEFINING POLICIES FOR ROOFTOP URBAN HORTICULTURE

F. Orsini - ResCUE-ABResearch Center in Urban Environment for Agriculture and Biodiversity

Department of Agricultural Sciences

Alma Mater Studiorum, University of Bologna

37% of population involved on urban horticulture

6 millions balcony/rooftop gardens

Urban Horticulture in Italy

Coldiretti, 2011

10 millions of vegetable gardens

8 millions balcony/rooftop gardens Grow the Planet, 2013

Why gardening?

44% healthy products

30% keeping traditions

30% anti-stress functions

27% open-air activities

Nomisma, 2013

Rooftop Urban Horticulture along

human history

Gardens on building rooftops

in ancient Babylon

Liz ChristyGarden

In the seventies, the crisis

resulted in thousands of

empty buildings: more than

25’000 in the only city of

New York

Community garden, such as

the Liz Christy Garden, start

to appear.Liz Christy Garden, NYC, 1973.

Vertical farming vs Rooftop Gardens

Gotham Green rooftop greenhouse, NYC

Vertical farm Render and current building status, Singapore

Vertical farms-First green skyscrapers

ready after 2020 (Despommier, 2009)

-Cost = 10 to 12.5 Euroskg-1 (Schubert, 2012)

Rooftop gardens-Possibility to adapt already existing buildings

to vegetable cultivation (Grewal and Grewal 2011)

-Possibility to use Simplified Hydroponics (Orsini

et al, 2014)

-Improve the resource efficiency of the building (heat, cooling, water, etc.) (Specht et al,

2013)

The smart way to Rooftop Horticulture

Il Virgolone con Serra (The virgolone

greenhouse). Antonio Scarponi /

Conceptual Devices,, elaborated from a

photo by Francesco Calzolari.

Are policies and

regulations good or

bad for Rooftop

Urban Horticulture

(RUH)?

Polic

ies

Legal instruments (laws, by-laws, ordinances)

Economic tools (tax incentives, subsidies)

Communicative/educational tools

Urban design instruments (e.g. availability of flat roofs)

Dubbeling M, van Veenhuizen R, de Zeeuw H (2010) Cities, poverty and food: multi-

stakeholder policy and planning in urban agriculture. Practical Action Pub, Rugby.

Which are the policies that can

affect RUH?

Are there in italy

policies and regulations

specifically addressing

Rooftop Urban

Horticulture (RUH)?

NO!

Polic

ies General Actions

e.g. Ethical policies

e.g. Food policies

Specific domains

e.g. Food production

e.g. Building contruction

National

How can we classify RUH-related

policies?

Regional LocalInternational

Example of international food policies

that can interact with RUH?

In October 2015, mayors of

more than 100 cities from all

over the world committed to the

“Milan Urban Food Policy Pact”,

the first international protocol

that calls for cities to develop

sustainable food systems that

grant healthy and accessible

food to all, protect biodiversity

and reduce food waste.

Two towers, 30 floors.

… 7’000 to 9’000 Euros m-2

What about social justice?

What about local inhabitants?

Vertical forest(Stefano Boeri Architects)

800 trees 4500 shrubs 15000 herbaceous

plants

Example of national policies that can

interact with RUH

Available contributions for installing green roofs

within the “2016 Stability law” also renewed in

2017 (although with reduced funds).Up to 65% of the

investment may be

deduced from taxes.

Green roof at ATM, Viale Sarca,

Milan

Example of regional laws that can

interact with RUH

The R.I.E. (Riduzione Impatto Edilizio, Reduction of

Building Impact), as defined within the “Urban Flood

Mitigation and Green Management Plan” allows

calculation of the avoided impact of buildings by green

infrastructure creation.

Calculation of RIE bases on the ratio of

greened surface area over the total

surface, multiplied by coefficients on

albedo, thermal insulation and flood

management.

The UNIBO experimental green roof at

Engineering Dept of Via Terracini, Bologna.

Example of local policies that can

interact with RUH

From 2010, the Emilia-Romagna Region and Bologna

City council promoted the creation of the first rooftop

community garden on the social housing buildings of Via

Gandusio.

Between 2010 and 2012,

three rooftop gardens were

installed and inhabitants

involved in workshops for

building and managing the

gardens.

The Via Gandusio social housing

buildings.

Via Gandusio, Bologna

Multifunctionalityof RUH

If all the 82 ha of available flat

rooftops would be greened, up to ¾ of

the city freshvegetables

requirements couldbe covered.

94 km0.67 km km-2

Implementation of green corridors by connectingRTGs within 500 m distance (sufficient for mostApoidea pollinators and beneficial predators)(Gathmann et al. 2002; Osborne et al. 2008; Zurbuchen et al. 2010; Ludgren 2009)

Orsini et al. (2014). Exploring the production

capacity of rooftop gardens (RTGs) in urban

agriculture: The potential impact on food and

nutrition security, biodiversity and other

ecosystem services in the city of Bologna. Food

Security, 6: 781-792.

CER

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2010 2011 2012 2013 2014 2015 2016 2017 2018

Part

icip

ants

(n)

Gre

ened

surf

ace

(m2)

Greened Surface Participants

Start, Via Gandusio,

10

Start, Via Gandusio, 6 and 12

Start, social events

Stop, Gandusio,

10

Stop, building closure

Francesco ORSINIAgricultural Sciences Department

f.orsini@unibo.it

http://www.unibo.it

http://www.dipsa unibo.it/

Thank you for your kind attention!