Changes in long-term light properties of a mixed conifer–broadleaf forest in Southwestern Europe
Fecha
2021Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
|
10.3390/f12111485
Resumen
Natural and anthropogenic factors affect forest structure worldwide, primarily affecting
forest canopy and its light properties. However, not only stand-replacing events modify canopy
structure, but disturbances of lower intensity can also have important ecological implications. To
study such effects, we analyzed long-term changes in light properties of a conifer–broadleaf mixed
forest in the ...
[++]
Natural and anthropogenic factors affect forest structure worldwide, primarily affecting
forest canopy and its light properties. However, not only stand-replacing events modify canopy
structure, but disturbances of lower intensity can also have important ecological implications. To
study such effects, we analyzed long-term changes in light properties of a conifer–broadleaf mixed
forest in the Southwestern Pyrenees, placed in the fringe between the Mediterranean and Eurosi-
berian biogeographical regions. At this site, a thinning trial with different intensities (0%, 20%, and
30–40% basal area removed) took place in 1999 and 2009, windstorms affected some plots in 2009 and
droughts were recurrent during the sampling period (2003, 2005, 2011). We monitored light properties
during 14 years (2005–2019) with hemispherical photographs. We applied partial autocorrelation
functions to determine if changes between years could be attributed to internal canopy changes or
to external disturbances. In addition, we mapped the broadleaf canopy in 2003, 2008, and 2016 to
calculate broadleaf canopy cover and richness at the sampling points with different buffer areas of in-
creasing surface. We applied generalized linear mixed models to evaluate the effects of light variables
on canopy richness and cover. We found that light variables had the most important changes during
the period 2008 to 2010, reacting to the changes caused that year by the combined effects of wind and
forest management. In addition, we found that an area of 4.0 m radius around the sampling points
was the best to explain the relationship between light properties and species richness, whereas a
radius of 1.0 m was enough to estimate the relationship between light and canopy cover. In addition,
light-related variables such as diffuse light and leaf area index were related to species richness,
whereas structural variables such as canopy openness were related to canopy cover. In summary, our
study demonstrates that non stand-replacing disturbances such as windstorms, thinning, or droughts
can have an important role in modifying structural and light-related canopy properties, which in
turn may influence natural processes of stand development and ecological succession. [--]
Materias
Light properties,
Thinning,
Windstorms,
Sustainable forest management,
Hemispherical photography,
Time-series analysis
Editor
MDPI
Publicado en
Forests, 2021, 12, 1485
Departamento
Universidad Pública de Navarra. Departamento de Ciencias /
Nafarroako Unibertsitate Publikoa. Zientziak Saila
Versión del editor
Entidades Financiadoras
This research was funded by the Spanish Ministry of Economy and Competitiveness, grants
numbers AGL2006-08288, AGL2009-11287, AGL2012-33465, and AGL2016-76463-P. J.R.P. was funded
by the La Caixa Foundation and Caja Navarra Foundation, under agreement LCF/PR/PR13/51080004
in the framework of the Public University of Navarre’s “Captación de Talento” program.