Preface
Broadleaved evergreen forests where holm oak (Quercus ilex 1.) is almost
the only canopy tree are a distinctive ecosystem of the Mediterranean Basin.
Biogeographically, these forests lie between cool-temperate deciduous forests
to the north and drier shrublands to the south. In a more general view, they
are ecologically intermediate between these deciduous forests and humid
warm-temperate evergreen forests, such as the laurisilva of the Macaronesian islands or the broadleaved evergreen forests of eastern Asia. Holm oak
forests are characterized by small-stature trees (usually 5 to 12 m tall), which
are slow growing, cast a deep shade, and have small, evergreen, sclerophyllous leaves. Summer drought is the major environmental constraint.
Mediterranean broadleaved evergreen forests have been underrepresented in the open literature. For example, The Woodlands Data Set of the
International Biological Program (IBP) contained data from just one holm
oak forest plot, Le Rouquet in southern France (Reichle 1981). Also, some
models of European forests consider just two major forest types, broadleaved deciduous and evergreen conifers, forgeting the extensive forests and
woodlands of holm oak and cork oak (Quercus suber 1.), which are the major evergreen oak tree species in the Mediterranean Basin. The extensive literature on Mediterranean-type ecosystems has also largely neglected these
forests, being centred mostly on Mediterranean-type shrublands.
To bridge this gap in knowledge, a research programme on the ecology of
holm oak forests was started in 1978 under the direction of Ramon Margalef,
Jaume Terradas, and Antoni Escarn~. This programme brought together researchers from three Spanish universities: the University of Barcelona, the
Autonomous University of Barcelona, and the University of Alicante.
The programme was originally intended to obtain a functional understanding of holm oak forests, combining three approaches: catchment budgets, plot-level analyses of the distribution and cycling of matter, and ecophysiological studies. Its inception was inspired by the IBP plot studies, particularly those conducted by Maurice Rapp in Montpellier (France) and by
P. Duvigneaud and Simone Denaeyer-De Smet in Belgium, and by the
catchment ecosystem studies pioneered by F. Herbert Bormann and Gene E.
Likens at Hubbard Brook (USA). The programme later evolved to include
also demographic approaches to forest dynamics.
In the 1970s, closed-canopy holm oak forests were still considered the
paradigm of the natural, undisturbed ("climacic") vegetation in those parts
Broadleaved evergreen forests where holm oak (Quercus ilex 1.) is almost
the only canopy tree are a distinctive ecosystem of the Mediterranean Basin.
Biogeographically, these forests lie between cool-temperate deciduous forests
to the north and drier shrublands to the south. In a more general view, they
are ecologically intermediate between these deciduous forests and humid
warm-temperate evergreen forests, such as the laurisilva of the Macaronesian islands or the broadleaved evergreen forests of eastern Asia. Holm oak
forests are characterized by small-stature trees (usually 5 to 12 m tall), which
are slow growing, cast a deep shade, and have small, evergreen, sclerophyllous leaves. Summer drought is the major environmental constraint.
Mediterranean broadleaved evergreen forests have been underrepresented in the open literature. For example, The Woodlands Data Set of the
International Biological Program (IBP) contained data from just one holm
oak forest plot, Le Rouquet in southern France (Reichle 1981). Also, some
models of European forests consider just two major forest types, broadleaved deciduous and evergreen conifers, forgeting the extensive forests and
woodlands of holm oak and cork oak (Quercus suber 1.), which are the major evergreen oak tree species in the Mediterranean Basin. The extensive literature on Mediterranean-type ecosystems has also largely neglected these
forests, being centred mostly on Mediterranean-type shrublands.
To bridge this gap in knowledge, a research programme on the ecology of
holm oak forests was started in 1978 under the direction of Ramon Margalef,
Jaume Terradas, and Antoni Escarn~. This programme brought together researchers from three Spanish universities: the University of Barcelona, the
Autonomous University of Barcelona, and the University of Alicante.
The programme was originally intended to obtain a functional understanding of holm oak forests, combining three approaches: catchment budgets, plot-level analyses of the distribution and cycling of matter, and ecophysiological studies. Its inception was inspired by the IBP plot studies, particularly those conducted by Maurice Rapp in Montpellier (France) and by
P. Duvigneaud and Simone Denaeyer-De Smet in Belgium, and by the
catchment ecosystem studies pioneered by F. Herbert Bormann and Gene E.
Likens at Hubbard Brook (USA). The programme later evolved to include
also demographic approaches to forest dynamics.
In the 1970s, closed-canopy holm oak forests were still considered the
paradigm of the natural, undisturbed ("climacic") vegetation in those parts