Street www.bcn.cat/mediambient Tree Management in Barcelona Printed on recycled paper Printed on recycled Street Tree Management in Barcelona Edited by Hàbitat Urbà. Ajuntament de Barcelona (Barcelona City Council) December 2011 Text Department of Urban Services and the Environment. Barcelona City Council Department of Green Area Management Department of Knowledge Management Department of Environmental Education Photographs Records office – Department of the Environment Historical Archive of Barcelona Lydia Chaparro Jordi Roy Cover photograph: Vicente Zambrano. Department of Image and Publications Translation Chris Gladwin, Manners Traduccions, SL Graphic design and layout Jordi Salvany Print www. print-makers.com Index Managing a natural heritage 5 Preamble 7 I. The Urban Tree 1. Some historical notes 9 2. How do trees function? 11 3. Trees and the environment 12 4. Some good reasons for planting trees 14 5. How are the species chosen? 16 6. Breakdown of the streets trees in Barcelona 17 7. The lifecycle of a tree in Barcelona 19 II. Street Tree Management in Barcelona 8. Management basics 21 9. The right tree in the right place 22 10. The selection of trees and palm trees 25 11. Deciding when to plant 28 12. Planting work 29 13. Irrigation 32 14. How is pruning carried out? 33 15. Tree health 35 16. Safety measures at work 39 17. Protecting the trees 40 18. Data management 43 III. Communication and Environmental Education 19. Learning about the trees in the city 45 IV. Bibliography 48 The trees in the streets of Barcelona 49 La Rambla in Barcelona Managing a natural heritage Taking a stroll at midday in summer in constitute the basis of street tree man- Barcelona would be a torture if there were agement in Barcelona. These are as fol- no trees in the streets. In a Mediterranean lows: city like this one, trees moderate the tem- Firstly, sustainability, with a selection peratures and make public spaces more of species suited to the environmental user-friendly with their shade and cool, conditions and intended to increase diver- and they mark the rhythm of the seasons sity by ensuring no one species exceeds and add colours and scents to the urban 15% of the total. The reasoning behind landscape. At the same time, although this objective, which is being achieved it is not so noticeable, they help to clear gradually, is to avoid monospecific popu- dust and purify the air we breathe. lations vulnerable to pests and diseases. Even so, we often don’t notice the Secondly, the creation of a diverse and trees in the street until one day, sud- identifiable landscape: every street, every denly, a jacaranda, a lime or an Indian neighbourhood is unique, and trees help bead tree surprises us with the gift of its to reaffirm this identity. For example, the flowers and scents. And without trees the main streets in the Eixample are associ- city would be unrecognisable. They are, ated with the London plane, just as palm together with the parks and gardens, Bar- trees help to identify the coastline and celona’s great green heritage; an invalu- ring roads. able heritage that must be looked after And lastly, knowledgeable and efficient carefully to guarantee its conservation management, which is needed to protect and improvement. our tree heritage by taking advantage of The guide you have in your hands is new technologies that allow us to unify intended to draw attention to the role of our efforts and save resources. trees in the city, especially in the current I hope this handbook will help you to context of climate change, and explain learn more about the trees on the streets how they are managed to obtain greater of Barcelona, which play a major role in benefits, while trying to apply a universal our welfare, and the work of the special- maxim in the world of arboriculture: “The ists responsible for their daily care, whom right tree in the right place.” I would like to thank for their efforts and You will also find the principles that commitment. La Rambla in Barcelona Preamble Few images more clearly identify Barce- was drawn up and signed in Barcelona on lona than the Eixample district with its the occasion of the first congress of the tree-lined streets. The people of Barce- Spanish Association of Arboriculture. This lona lay great importance on this natural Charter establishes the rights of trees heritage. An example of this is that when in the urban environment. It recognises we want to commemorate an act or an them as one of the essential factors “guar- event or keep alive a memory, we often anteeing the life” of the city and requires choose to do so by planting a tree, a living that their introduction “should be given organism. maximum attention”. It also requires that That trees are essential in a dense com- the network of trees “should be evaluated, pact city like Barcelona is also confirmed planned and managed”, and affirms that by city council policy, which is committed “they help to establish culture at a local to increasing the number and quality of level and improve living conditions in the trees in the streets in view of the many so- urban environment”. cial and environmental benefits they bring Since it was presented, a large number to the city. Therefore, it is no coincidence of towns around Spain have signed the that the Barcelona Charter, the “Declara- Barcelona Charter. It establishes the fol- tion of the Rights of Trees in the City”, lowing commitments: Commitments contained in the Declaration of the Rights of Trees in the City E To situate trees in their basic role as one of the city’s principal heritage resources. E Comprehensive and continuous preparation and promotion of information, inventories, management techniques, practices, procedures, products, services and standards that fa- cilitate the introduction of trees in the city in fitting and decent conditions. E To disseminate information: to inform and educate the general public, the various profes- sional groups, the industrial and service sectors, schools, colleges and universities, about the basic importance of trees for life in the city. E To establish policies, rules, regulations and practices in city government and administra- tion that ensure optimal conditions for the life of trees. E To reconsider all the elements that currently make up urban space and think ahead from the standpoint of the requirements and potential of the urban tree network as regards the conception, planning, creation, management, use and reuse of this public space. I. The Urban Tree Passeig de Gràcia, 1953 Passeig Street Tree Management in Barcelona 9 1. Some historical notes The first trees to be planted “The work on this boulevard began in The Rambla was the first public place – of 1821, and as time went by, several gardens which there is any record – to be planted for the enjoyment of the people of Bar- with trees. In 1702 and 1703, 280 pop- celona were laid out along its sides. This lars were planted, which were cut down street was already mentioned in 1760 as shortly after and replaced with alternat- one of the main avenues, and in 1826 they ing poplars and elms. planted acacia, plane trees, ash, mulber- In the description of the tree-planting ry trees, poplars, willows, oleanders [sic], project drafted by the counsellors Ger- and some holm oaks probably coming mán de Salvador and Carles Arnau it is from the farms round about, such as the explained that: one still existing today in front of number 103.” (Villoro i Martin, 1984) “As the main decoration in the Ram- bla itself, the planting in it of lines of The Cerdà Plan leafy trees of different species is neces- sary, as in other cities and towns which In 1854, Barcelona’s old city walls were are the wonder of all Europe and admired demolished and it was necessary to plan by foreigners and inhabitants alike, and the development of the area extending as the same as the four lines of trees that far as the surrounding villages. In 1859 have already been planted from the street the Cerdà Plan was approved, which pro- known as Carrer de la Adressana to the posed the “Eixample”, an expansion of corner of the Carrer de Escudellers, which the city stretching from Montjuic to the are irrigated with great ease with the River Besòs, with an orthogonal layout water moved by three waterwheels and consisting of rectilinear streets twenty the well in the convent of Santa Monica, metres wide, forming a grid of square aided by the device of a pump. And be- blocks 113.3 metres long on each side. ing universally acclaimed in all respects Cerdà, following the fashion of most by people both high and humble, there other European cities – for example, Paris emerges the particular obligation to con- and its boulevards planned out by Hauss- tinue them along the whole Rambla, even mann and Alphand – decided that the more so as the clemency of the weather major avenues and streets in the Eixam- favours the planting of trees, and there is ple should be lined with large trees plant- equally well good recourse to water for ir- ed to provide shade in the city, with a tree rigation.” (Carreras Candi, 1916) every eight metres. Moreover, according to the original plans one of the four pave- The Passeig de Gràcia ments delineating each block was meant to be twice as wide and would therefore According to Joan Villoro in the book Guia have had a double line of trees. dels espais verds de Barcelona (Guide to However, during the time it took to green spaces in Barcelona), the first ex- build the Eixample – about a century – the ample of a street with lines of trees in- modifications made to the plan conflicted cluded in its urban planning project was with the initial project and many of the the Passeig de Gracia, which was then the original ideas were never implemented.