Drought-induced changes in wood density are not prevented by thinning in Scots pine stands
Fecha
2018Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
|
10.3390/f9010004
Resumen
Density is an important wood mechanical property and an indicator of xylem architecture
and hydraulic conductivity. It can be influenced by forest management and climate. We studied the
impact of thinning and climate variables on annual stem radial growth (ring width and ring density,
and their earlywood and latewood components) in two contrasting Scots pine (Pinus sylvestris L.)
stands in no ...
[++]
Density is an important wood mechanical property and an indicator of xylem architecture
and hydraulic conductivity. It can be influenced by forest management and climate. We studied the
impact of thinning and climate variables on annual stem radial growth (ring width and ring density,
and their earlywood and latewood components) in two contrasting Scots pine (Pinus sylvestris L.)
stands in northern Spain (one continental, one Mediterranean). At each site, three thinning regimes
(control or T0, removing 20% basal area or T20, and removing 30% or T30) were randomly applied to
nine plots per site (three plots per treatment) in 1999. Thinning was repeated at the Mediterranean
site in 2009 (increasing thinning intensity in T30 to 40%). Eight trees per plot were cored in spring
2014. Second thinning at the Mediterranean site and first thinning at the continental site generally
caused significantly wider ring (RW), earlywood (EW) and latewood (LW) widths, although no
differences between T20 and T30/40 were found, supporting in part the common observation that
radial growth is enhanced following thinning as competition for water and nutrients is reduced.
At the Mediterranean site, values of latewood density (LD) and maximum density (Dmax) relative to
pre-thinning conditions were significantly lower in T0 than in T30. However, at the continental site,
relative changes of ring density (RD) and LD were significantly higher in T0 than in T20 and T30.
Climate significantly affected not only RWbut also RD, with significant RD drops during or right after
unusually warm-dry years (e.g., 2003, 2011), which were characterized by LD reductions between
5.4 and 8.0%. Such RD decreases were quickly followed by recovery of pre-drought density values.
These results indicate trees temporarily reduce LD as a way to enhance hydraulic conductivity during
dry summers. However, climate effects on wood density were site-dependent. We also detected that
the thinning effect was not intense enough to prevent drought-induced changes in wood density by
altering water availability, but it could help to reduce wood properties fluctuations and therefore
maintain more homogeneous wood mechanic features. [--]
Materias
Dendroecology,
Scots pine,
Tree-ring width,
Wood density,
X-ray,
Densitometry,
Drought
Editor
MDPI
Publicado en
Forests 2018, 9 (1), 4
Departamento
Universidad Pública de Navarra. Departamento de Ciencias del Medio Natural /
Nafarroako Unibertsitate Publikoa. Natura Ingurunearen Zientziak Saila
Versión del editor
Entidades Financiadoras
E.G.A. was
funded through a Spanish Predoctoral Research Grant (ref. BES-2013-066705). Funding for this research has been
provided by the Spanish Ministry of Economy and Competitiveness (project AGL2012-33465), which also funded
Y.-H.L. J.A.B. was funded through a Ramón y Cajal contract (ref. RYC-2011-08082) and a Marie Curie Action
(ref CIG-2012-326718-ECOPYREN3), which also funded D.C.-P. Funds to cover the costs of publishing in open
access were provided by the OpenAIRE pilot program of the European Union 7th Framework Programme.