Experimental Areas of Prades and Montseny
23
until recently. Other frequent understory species are the shrubs (occasionally
small trees) Phillyrea latifolia subsp. media and Crataegus monogyna. Major
species in the sparse field layer are Quercus ilex seedlings, Hedera helix,
Rubus ulmifolius, Brachypodium sylvaticum, Melica unijlora, Pteridium
aquilinum, Asplenium adiantum-nigrum, and Teucrium scorodonia. Phytosociologically, these holm oak forests are classed as belonging to the association Asplenio-Quercetum (=Quercetum mediterraneo-montanum).
Research at the Figaro experimental area was done on a 900-ha forest
made up of pure holm oak stands, pure Aleppo pine (Pinus halepensis)
stands, and mixed holm oak-Aleppo pine stands. This forest is representative
of the western sector of the Montseny massif at low and mid altitudes. The
overstory is dominated by holm oak and/or Aleppo pine, with Pinus pinea,
Quercus cerrioides, Arbutus unedo and Erica arborea occasionally joining in.
Holm oak is the dominant tree species in most of the sampling plots whose
results have been used in this book.
Holm oak forests at Montseny were heavily exploited for charcoal production until ca. 1955. Coppicing took place typically at intervals of 10-15 years
(Gutierrez 1996; Sect. 1.6). After charcoal production was discontinued,
fellings were restarted in many holm oak forests after the mid-1970s for firewood production. Privately owned holm oak forests, such as those in our Figaro experimental area, are now managed for firewood through selection
thinnings every 20-30 years (Retana et al. 1992). Selection thinning consists
of a partial removal of standing trees, with the highest intensities of felling
directed at the largest stems (dbh > 15-20 cm) and at the abundant suppressed stems resprouted after the last thinning. Thinnings remove about
30-60% of the pre-thinning basal area and aboveground biomass (Retana
et al. 1992).
The history of holm oak forests in the Torrent de la Mina catchment at La
Castanya is somewhat more complex. Part of the permanent plot near the
outlet of the catchment is relatively flat and it was cultivated in the past. It
was abandoned, probably sometime between ca. 1880 and 1920, and colonized by seed-derived holm oaks that have never been cut, as evidenced by
their single stems. The other, steeper, part of the plot was coppiced for firewood and charcoal more or less continuously, as all the rest of the holm oak
forest within the catchment. The lower slopes of the catchment, mainly between altitudes of 700 and 800, m were subject to slash-and-burn agriculture,
as reflected by place names and by the present structure of the forest, with an
open canopy of low holm oak trees and a dense understory of the shrub Erica arborea. Since the 1950s the holm oak forests of the catchment have remain unmanaged, except for two small areas that were thinned, one around
1965 and the other in 1979.
Fire has not occurred in any of our forest sites at Montseny for decades.
Grazing or browsing by domestic herbivores is very limited in our sites, except in the heathlands and grasslands in the upper part of the TMO catchment.
23
until recently. Other frequent understory species are the shrubs (occasionally
small trees) Phillyrea latifolia subsp. media and Crataegus monogyna. Major
species in the sparse field layer are Quercus ilex seedlings, Hedera helix,
Rubus ulmifolius, Brachypodium sylvaticum, Melica unijlora, Pteridium
aquilinum, Asplenium adiantum-nigrum, and Teucrium scorodonia. Phytosociologically, these holm oak forests are classed as belonging to the association Asplenio-Quercetum (=Quercetum mediterraneo-montanum).
Research at the Figaro experimental area was done on a 900-ha forest
made up of pure holm oak stands, pure Aleppo pine (Pinus halepensis)
stands, and mixed holm oak-Aleppo pine stands. This forest is representative
of the western sector of the Montseny massif at low and mid altitudes. The
overstory is dominated by holm oak and/or Aleppo pine, with Pinus pinea,
Quercus cerrioides, Arbutus unedo and Erica arborea occasionally joining in.
Holm oak is the dominant tree species in most of the sampling plots whose
results have been used in this book.
Holm oak forests at Montseny were heavily exploited for charcoal production until ca. 1955. Coppicing took place typically at intervals of 10-15 years
(Gutierrez 1996; Sect. 1.6). After charcoal production was discontinued,
fellings were restarted in many holm oak forests after the mid-1970s for firewood production. Privately owned holm oak forests, such as those in our Figaro experimental area, are now managed for firewood through selection
thinnings every 20-30 years (Retana et al. 1992). Selection thinning consists
of a partial removal of standing trees, with the highest intensities of felling
directed at the largest stems (dbh > 15-20 cm) and at the abundant suppressed stems resprouted after the last thinning. Thinnings remove about
30-60% of the pre-thinning basal area and aboveground biomass (Retana
et al. 1992).
The history of holm oak forests in the Torrent de la Mina catchment at La
Castanya is somewhat more complex. Part of the permanent plot near the
outlet of the catchment is relatively flat and it was cultivated in the past. It
was abandoned, probably sometime between ca. 1880 and 1920, and colonized by seed-derived holm oaks that have never been cut, as evidenced by
their single stems. The other, steeper, part of the plot was coppiced for firewood and charcoal more or less continuously, as all the rest of the holm oak
forest within the catchment. The lower slopes of the catchment, mainly between altitudes of 700 and 800, m were subject to slash-and-burn agriculture,
as reflected by place names and by the present structure of the forest, with an
open canopy of low holm oak trees and a dense understory of the shrub Erica arborea. Since the 1950s the holm oak forests of the catchment have remain unmanaged, except for two small areas that were thinned, one around
1965 and the other in 1979.
Fire has not occurred in any of our forest sites at Montseny for decades.
Grazing or browsing by domestic herbivores is very limited in our sites, except in the heathlands and grasslands in the upper part of the TMO catchment.