Detecting the impact of climate and disturbances on tree-rings of Fagus sylvatica L. and Quercus robur L. in a lowland forest in Cantabria, Northern Spain

Abstract

-The influence of climate and disturbances on tree-ring widths of European beech and pedunculate oak were evaluated in a lowland forest of Northern Spain. From 1925 to 1980, 36% of the variance of beech ring-width and 29% of the oak one was explained by climate. The climatic models showed that low precipitation in July of the previous year limited the radial growth of beech, while oak one was instead restricted by water deficits in July of the current year. Ten main disturbance periods were identified from 1780 to 1997, among which the 1922-1935 one was the most important. Since beech trees showed suppressed growth from 1800 to 1920, probably the forest canopy became denser during this time. The disturbance periods identified in 1922-1935 and 1948-1953 contributed to both increase the growth of beech above the expected, and intensify its climatic response. On the other hand, deviations of oak growth from the expected without-disturbance indices agreed with the disturbance history up to 1850. From 1850 to 1997, oak growth became independent from disturbances sequence, yielding a constant climatic response in . The opposite effects of disturbances on both the radial growth and the climatic response of European beech and pedunculate oak are related to their different tolerance to shade. These results have relevant methodological implications on the analysis of climate-growth relationships, and on the reconstruction of past disturbance regimes by means of dendroecological techniques. dendroecology / ring width / response function / forest disturbance / Kalman filter Résumé -Effet du climat et des perturbations locales sur la croissance radiale de Fagus sylvatica L. et Quercus robur L. dans une forêt naturelle de Cantabria, Nord de l'Espagne. L'influence relative du climat et des perturbations locales sur la croissance radiale du hêtre et du chêne pédonculé a été analysée dans une vieille forêt naturelle du Nord de l'Espagne. Entre 1925 et 1980, 36 % de la variance des largeurs de cernes du hêtre et 29 % de celle du chêne s'expliquent par le climat. Les modèles climatiques élaborés montrent que la croissance radiale du hêtre est limitée par les précipitations du mois de juillet de l'année précédente, alors que celle du chêne l'est par le déficit hydrique du mois de juillet de l'année en cours. Dix périodes de perturbation de la croissance, d'origine non climatique, ont été identifiées entre 1780 et 1997, parmi lesquelles celle de 1922-1935 a été la plus importante. La croissance radiale des hêtres apparaît faible de 1800 à 1920 en raison de la fermeture du couvert forestier au cours de cette période. Puis des perturbations survenues en 1922-1935 et 1948-1953 entraînent une augmentation de la croissance, qui devient alors supérieure au signal commun. Conjointement, la réponse aux contraintes climatiques se renforce au cours des mêmes périodes. Chez le chêne, les dévia-tions de la croissance par rapport au signal commun sont en accord avec l'historique des perturbations locales jusqu'en 1850. Puis la croiss...

Climate-tree-growth relationships ofQuercus petraeaMill. stand in the Forest of Bercé (“Futaie des Clos”, Sarthe, France)

“…A stronger correlation can probably be achieved by using daily climatic data grouped into periods of different lengths [5,17,29]. Even if low, the percentage of explained variance is within the usual range in other Europe localities [5,8,27,35,38,44,49].…”

“…Autoregressive modeling of the residuals and biweight robust estimation of the mean were used to calculate chronology indices for each ring component [11,44]. These master chronologies were used to evaluate the radial growth-climate relationships.…”

“…The raw ring-widths were standardized by means of a two-step procedure using the program ARSTAN [24]: the series were first fit to a negative exponential or straight line and then to a cubic smoothing spline with a 50% frequency response of 50 years, which is flexible enough to reduce considerably non-climatic variance [11,44]. Autoregressive modeling of the residuals and biweight robust estimation of the mean were used to calculate chronology indices for each ring component [11,44].…”

Height increment of hybrid aspen <i>Populus tremuloides</i> x <i>P. tremula</i> as a function of weather conditions in central part of Latvia

“…Although this is usual in arid regions (i.e. Mediterranean region) (Rozas 2001;Andreu et al 2007), similar effects have recently been observed also for trees growing in boreal regions (Wilmking et al 2004). Thus, knowledge on climate growth relationships, considering regional variability (Andreu et al 2007), is necessary.…”

“…speed of cell division, differentiation and elongation) (Pallardy 2008) and assimilation (Berry and Downtown 2012), which affects growth, particularly in the second part of growing period (Barbaroux and Breda 2002). The amount of precipitation, which is often significant for tree growth in southern and central parts of specie's distribution area (Rozas 2001;Kelly et al 2002;Jansons et al 2013), did not show significant effect on HI of hybrid aspen ( Table 1), suggesting that the availability of water was not limiting height growth throughout the entire vegetation season. Probably, precipitation might be significant for HI in June-August, when temperature is the highest (Fig.…”