Rolland C., Petitcolas
V., Michalet R. (1998). Changes in radial tree growth for Picea abies,
Larix decidua, Pinus cembra and Pinus uncinata near the
alpine timberline since 1750. Trees, Structure and function 13(1): 40-53.
- TITLE Changes in radial tree growth for Picea
abies, Larix decidua, Pinus cembra and Pinus uncinata near
the alpine timberline since 1750.
- LANGUAGE English , with English abstract.
- SPECIES Picea abies (L.) Karst.,
Pinus cembra L., Larix decidua Mill., Pinus uncinata Mill.
- KEY WORDS Global change, Timberline,
Dendroclimatology, Tree-ring, Conifers.
- MOTS CLES Changement global, Limite
supérieure de la forêt, Dendroclimatologie, Cernes de croissance,
- SITES Achard and Pourettes in Belledonne
mountains. Chal, Le Biol, Bellecôte, Tuéda and Saint Jacques in the
Moyenne-Tarentaise, Mollard Fleury, Le Jeu, Barbier, Tuéda and Plan d'Amont
in the Haute-Maurienne. Les Ayes, Izoard and Granon in the Briançonnais
- ABSTRACT (English)
Changes in radial growth of the four coniferous species growing in the French
Alps near the upper treeline were investigated. Thirty-seven populations of
Norway spruce [Picea abies (L.) Karst.], European larch (Larix
decidua Mill.), Swiss stone pine (Pinus cembra L.) and
mountain pine (Pinus uncinata Mill. ex Mirb.) were sampled by taking
1320 cores and analysing tree-ring widths. Sites were chosen in various
climatic conditions (macroclimate and aspect) and on two kinds of bedrock in
order to take into account the ecological behaviour of these species.
Belledonne, Moyenne-Tarentaise, Haute-Maurienne and Briançonnais areas were
sampled along increasing gradients of summer aridity and winter
continentality. The calculation of time series after removing the age trend
brings strong evidence for an increase in radial growth during the two last
centuries, but with different stages and fluctuations for each species. This
growth trend is signifcantly enhanced since 1860 for the spruce, and since
1920 for the two pine species. Funhermore, it also appears on Larix decidua
with the same pattern despite periodical growth reduction due to attacks of
the larch bud moth (Zeiraphera diniana Gn.). The analysis of
ring-widths at a given cambial age reveals that this enhanced phenomenon is
observed especially during the tree's early years (25-75 years). The analysis
of four regional climatic series, and three longer series of temperature (in
farther single sites) reveals synchronous decadal fluctuations and an evident
secular increase in minimum temperatures (especially in January and from July
to October), that may be involved in treegrowth enhancement. Thermic
amplitudes are significantly reduced during the whole growing period, what is
more pronounced in Belledonne, the most oceanic region. Long term growth
changes are well described by stepwise regression models, especially for the
pine species. These models involved both a linear trend (CO2 concentration or
N-deposition) and low frequency of Turin monthly temperatures. However, they
show different pattems than those observed from response functions at a yearly