Landscapes Forest and Global Change - ESA - Escola Superior ...

F.J. Gómez et al. 2010. Land use changes and mixed forest dynamics. The case of Montiferru Mountains
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2.2 Material and methods
The analysis of land use and land cover change processes requires the ecological and social
criteria integration, linking socioeconomical and biophysical driving forces, so as to unravel
landscape dynamics complexity; in this aim hybrid methodologies based on holistic approaches
are basic tools to interpret them (Naveh 2000). In our case, there has been posed a diachronic
model and a synchronic model to analyze land use & cover changes.
Diachronic analysis comprises historical records related to land use and cartography for the
period 1965-2006. Information about forest use was taken from the review of Corpo Forestale
Regionale of Sardinia archive. Historical series was, in general, vague and unsystematic; for this
reason data was treated to homogenize records and to set (i) year and type of intervention
(familiar or commercial thinning) (ii) species and quantity of wood or firewood removed (using
dendrometric rates for Sardinian Quercus sp. and normalizing non explicit records into habitual
oak and holm oak cutting shift documented for the Montiferru). Besides, oral sources of
information were consulted to improve environmental history of the studied sites. Several
interviews were made to social actors related to Montiferru forestland sphere, especially
primary sector workers (woodcutters, shepherds, etc.) and forest owners and traders; a wide
majority of people interviewed were elderly men, owners of non written and usually non enough
considered information, but very valuable, regarding to relations between human and
environment. Four sampling stations were selected attending to differences on land use patterns
and classified in terms of intensity, considered high when commercial thinning is predominant
and low when are related to domestic use (up to 5 m³ per year); and recurrence, considered high
when there were more than 20 interventions during recorded period (1965-2006) and low in the
other cases (Table 1). Besides, diachronic model comprises the analysis of aerial photographs of
1955, 1977 and 2006. Spatial characteristics of mixed forestland patches corresponding to
sampling stations and its dynamics have been analyzed by GIS during this period.
Synchronic model comprises the analysis about mixed forestland mass’ ecological dynamics.
For this objective, 20 experimental 10x10 meters plots were randomly distributed into each
sampling station. In each plot, number and diameter at breast height (dbh) of oak and holm oak
(live and dead trees) were measured and classified into thee size class: saplings (dbh