Abstract:
The dynamics of Pinus
mugo krummholz during
concomitant change in
pastoral land use and
climate in central Italy
since the mid-20th century
was investigated.
Krummholz dynamics were
detected using sequential aerial photography and fitted to a
logistic regression model with elevation, grazing, proximity to
beech forest, and proximity to krummholz as explanatory
variables. Dendrochronological series were correlated with
temperature and precipitation and fitted to a linear model.
During this period krummholz doubled in extent and migrated
35–65 m upslope. Expansion was positively associated with krummholz proximity, residual pastoral grazing, and proximity to
beech forest beyond 10 m and negatively associated with
elevation and beech forest closer than 10 m. The logistic
regression model forecasts krummholz migration by an
additional 30 m upslope by 2060. During the 20th century,
winter and spring minimum temperatures increased but did not
result in increased radial stem growth of P. mugo. The
combined evidence suggests that krummholz dynamics can be
explained by the legacy of summer pastoralism and the
dispersal limitations of P. mugo, rather than by climate change.
