Starting an Oak Collection in Porto Botanical Garden, Portugal

by Carlos Vila-Viçosa, Joana Tinoco, and Paulo Farinha Marques

The Botanical Garden of Porto is located on the west side of the city of Porto, on a plateau overlooking the mouth of the Douro River and the Atlantic Ocean. Currently covering 4 hectares, it is part of the grounds of the University of Porto campus and is situated on what was once Quinta do Campo Alegre, a historic estate formerly on the outskirts of Porto. The property was bought in 1949 by the Portuguese government from the Andresen family to create the Botanical Garden, which was formally launched in 1951 as part of the Botanical Institute of the Faculty of Sciences of the University of Porto.

Views of Porto Botanical Garden (click on images to enlarge)

In 1954, Karl Koepp, a German landscape architect, drew its first master plan in order to adapt the estate into a Botanical Garden. The proposed plan focused on the conservation and adaptation of existing spaces as well as

Karl Koepp's master plan for Porto Botanical Garden

the creation of new gardens.

Today the Botanical Garden is an eclectic set of spaces dominated by the garden design styles of late 19th century/early 20th century and is organized in three main areas:

1) the central terrace, accommodating the main house, laid out with a set of historical theme gardens divided by tall clipped hedges of Camellia japonica, suggesting outdoor rooms of the Arts and Crafts movement;

2) the xerophytic garden and the green houses, with a large collection of cactus, orchids, and tropical plants in the intermediate levels;

3) the arboretum, with a significant collection of conifers and palm trees, plus temperate and pine groves, and a few emblematic oak specimens (Quercus suber and Q. imbricaria) and European hornbeam (Carpinus betulus), with a large lily pond occupying the lower levels.

Acknowledging the appalling conservation status of Iberian autochthonous flora and vegetation and considering its increasing rarity and uniqueness, it became one of the 

Spontaneous cork oak, remnant of local woodland

main missions of Porto Botanical Garden to increase the number of native species cultivated in the garden, always taking into account biogeographic patterns and congruent floristic assemblages. This ex-situ conservation initiative targeted oaks as topmost elements of the climax stages and tall scrub vegetation of the Mediterranean ecosystems.

The Garden possesses several mature spontaneous cork oak (Q. suber) specimens, remnants of the local potential woodland of northwest Portugal, which is a Q. robur subsp. broteroana forest characteristically

Quercus robur subsp. broteroana

enriched with Mediterranean and thermophilic taxa (Ruscus aculeatus, Arbutus unedo, and Viburnum tinus, among others). Foreign taxa are also included in the collection, in accordance with 19th century taste, and North American oaks are represented (Q. rugosa, Q. palustris, and Q. imbricaria), as well as Asian species such as Q. myrsinifolia.

In order to undertake a future increase in the collection of native oak species, several botanical expeditions are being made to collect acorns and seedlings throughout the country. The acorn collection covers all biogeographic regions and involves thorough georeferencing of mother trees and records of taxonomy and nomenclature, forest association, substrate, and geobotanical framework. In addition, more samples have been received from several arboreta, universities, and botanical gardens, and through foreign contacts with oak ecologists, taxonomists, and private collectors.

This work emerged in close collaboration with CIBIO (Research Centre in Biodiversity and Genetic Resources), where a PhD thesis on the phylogeography of Quercus section Galliferae Spach in the western Mediterranean 

Quercus canariensis seedling

Basin is being developed by Carlos Vila-Viçosa with the supervision of Professor Rubim Almeida from the Faculty of Sciences of Porto University, Cristina Garcia from CIBIO, and Francisco Vázquez Pardo from CICYTEX (Center for Scientific and Technological Research of Extremadura, Spain). Therefore, besides the targeted taxa, we intend to cover the maximum diversity of oak species and their origins, emphasizing collection from the typical locations where the different taxa and nothotaxa have been originally cited and described. Thus, we intend to create and complete a living collection that will be continuously studied, combining both integrative taxonomy and molecular tools.

We are already growing more than 100 seedlings of Q. canariensis, which is an endangered species according to the Red List of the National Flora (Vila-Viçosa ined.), sourced from a relict population in Southern Portugal (Relva-Grande, Odemira). These seedlings will be used for genetic diversity assessments and also for subsequent reinforcement and habitat recovery of this extremely threatened woodland.

We are also sprouting Q. pyrenaica from its southernmost European native area, in order to reinforce its known but severely threatened chorological limits. These typically deciduous woodlands are still surviving, with a marcescent behavior, in the midst of drier Mediterranean conditions and neighboring evergreen open woods. Not only do they enrich the local diversity, but they are also important for biodiversity conservation, as they harbor several taxa that survive in these peculiar edaphoclimatic “islands”. Aside from these species, since last October we have also started to germinate acorns of Quercus broteroi, Q. coccifera, Q. ×coutinhoi, Q. faginea, Q. rivasmartinezii, Q. robur subsp. broteroana, Q. rotundifolia, Q. rotundifolia f. calycina, Q. suber, and foreign provenances of Q. frainetto (Albania), Q. humboldtii (Colombia), Q. boissieri (Israel), and Q. rubra.

Quercus pyrenaica	Quercus rotundifolia	Quercus frainetto

Taking advantage of Porto’s climatic conditions (temperate macrobioclimate in a thermophile and hyperoceanic belt with mild winters) we can cover a wide variety of climatic and ecological niches, from tropical to Mediterranean ecoregions.

Porto Botanical Garden’s staff consists of a Director, Prof. Paulo Farinha Marques, Joana Tinoco, a landscape architect who coordinates the management and maintenance work of the Garden, and a team of five gardeners.

Team photo: (left to right) Iúri Frias, Carlos Vila-Viçosa, João Junqueira, Joana Tinoco, and Prof. Paulo Farinha Marques.

The collections stewardship is carried out by a passionate group of volunteers from various academic backgrounds: Iúri Frias, João Junqueira, and Carlos Vila-Viçosa. Using traditional knowledge and common gardening techniques such as sowing, cuttings, and grafting, we try to increase the number of individuals and select the fittest specimens so that they may be more resilient when returned to their natural habitat.

In the future, besides its educational objectives, the Arboretum of Porto Botanical Garden intends to engage in programs of conservation and reforestation, enhancing the ecological, ethnobotanical, and aesthetical interest of native flora. In addition, it aims to become a national reference in 

The nursery at Porto Botanical Garden

maintaining living collections for scientific purposes, particularly those of autochthonous climax species and some noninvasive ornamental exotics with historical relevance in the region, such as Camellia, Magnolia, Rhododendron, Araucaria, and Cedrus.

This commitment is not only relevant for the stimulation of classical botanical knowledge but more importantly for the conservation and promotion of oak landscapes in natural, rural, and urban contexts. These landscapes have an important role to play in tackling climate change, maintaining native biodiversity values, and significantly contributing to ecosystem services.