In Europe, people have managed forests and woodlands for centuries. Old pollarded oaks reflect historical legacies, and their conservation is threatened by the abandonment of this traditional forest ...use. However, site conditions (topography, soil features, land cover, and historical use) and warming-triggered drought stress also contribute to their growth decline, particularly in seasonally dry regions. We investigated two stands of pollarded Mediterranean oaks (Quercus subpyrenaica), where pollarding was abandoned in the 1950s, showing contrasting land cover and tree sizes in north-eastern Spain. Changes in land cover, soil characteristics (texture, pH, and nutrient concentrations), climate conditions, and tree-ring data (basal area increment −BAI−, and ring-width indices) were analysed. The Artosilla site, showing the smallest trees, presented the lowest long-term growth rates (period 1730−2022, mean BAI = 19.7 cm2 yr−1) as compared with the Aineto site with bigger oaks (mean BAI = 32.9 cm2 yr−1). Old trees were found in both sites with ages ranging 293−311 years. The less fertile soils in Artosilla, where pine plantations diminish canopy thermal amplitude, may contribute to the long-term growth decline observed there. Moreover, more major growth suppressions were found in this site, particularly in the 1940s, which suggest a more intensive historical use. Aineto showed a stronger BAI decline since the 1950s, which could be a response to increasingly warmer and drier summer conditions. In contrast, growth in Artosilla is decoupling from soil and atmospheric drought suggesting chronic growth stagnation. Poor site conditions (steeper slope, less fertile soils, intensive historical use) contributed to the decline of pollarded oaks. Active management is required to preserve these unique old, monumental trees.
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•Old pollarded oaks are subjected to other threats than pollarding abandonment.•Growth suppressions peaked in the 1940s after the Spanish Civil War.•Low growth rates were observed in a site with less fertile soils and higher pine cover.•Oak growth declined in response to dry-warm winter-spring and summer conditions.•Pollarded oaks are menaced by aridification and preserve historical land-use legacies.
Thinning focused on achieving growth and diameter management objectives has typically led to stands with reduced climate sensitivity compared to unthinned stands. We integrated dendrochronological ...with Airborne Laser Scanner (LiDAR) data and growth models to assess the long-term impact of thinning intensity on Canary pine (Pinus canariensis) radial growth. In 1988, 18 permanent treatment units were established in 73-year-old Canary pine plantations and three thinning treatments were applied (C–control-unthinned; 0% basal area removal; MT–moderate thinning: 10% and 15% basal area removal, and HT–heavy thinning: 46% and 45% basal area removal on the windward and leeward slopes, respectively). Dendrochronological data were measured in 2022 and expressed as basal area increment (BAI). The impact of climate on growth was examined by fitting linear regression models considering two different Representative Concentration Pathway (RCP) climate scenarios, RCP 2.6 and RCP 4.5. Finally, LiDAR data were used for standing segmentation to evaluate changes in overall growth under different climatic scenarios. The LiDAR–stand attributes differed between aspects. The BAI of the most recent 20 years (BAIsub.20) after thinning was significantly higher for the moderate and heavy treatments on the leeward plots (F = 47.31, p < 0.001). On the windward plots, BAI decreased after moderate thinning. Considerable thinning treatments resulted in stronger changes in growth when compared to RCP climatic scenarios. From a silviculture perspective, the mapping of canopy structure and growth response to thinning under different climatic scenarios provides managers with opportunities to conduct thinning strategies for forest adaptation. Combining dendrochronological and LiDAR data at a landscape scale substantially improves the value of the separate datasets as forecasted growth response maps allow improving thinning management plans.
•Wood anatomical time series of Chukrasia tabularis were developed.•Vessel features were strongly connected to local climate.•Chukrasia vessels can be used for paleoclimatic and ecophysiological ...studies in moist tropical forests.
Wood anatomical features such as vessels record paleo climatic and environmental signals through their physiological adjustment during the environmental stress condition. Using vessel features as environmental proxy is relatively new in tropical dendrochronology but very useful to study plant ecophysiological responses to changing environmental conditions. Here, we developed the first vessel chronologies of diffuse porous Chukrasia tabularis from a Bangladeshi moist tropical forest and assessed their suitability for Dendroclimatic and ecophysiological studies in moist tropical forests. Standard chronologies of ring-width (RW), vessel number (NV), mean vessel area (MVA), total vessel area (TVA), total vessel area % (TVAP), mean vessel tangential diameter (MVTD), mean vessel radial diameter (MVRD), and vessel density (VD) were developed which spanned the period 1925–2015. Principal component analysis revealed that all chronologies were related among each other, the first two principal axis explaining 80% of the common variance. Hence, all chronologies shared a common environmental signal, except TVAP and MVRD which were excluded from further dendroclimatic analysis. Bootstrap correlation function was used to test the relationship between the chronologies and climate variables over 1950–2015. All chronologies were significantly correlated with monthly, seasonal and annual climate variables but varied in their magnitude. Spring temperatures (March–April) and late monsoon precipitation had the dominant influence on the vessel features and radial growth of Chukrasia tabularis. Decreased vessel area (Hydraulic efficiency) and increased vessel density (Hydraulic safety) were observed in response to stress environmental condition particularly in the spring (hot and dry) when evapotranspiration became higher and soil moisture deficit occurs due to high temperatures. Moving correlation functions revealed stable climate tree-ring variable relationships during March–April and October with an increasing tendency of climate interaction in other months. Our study shows that vessel features in Chukrasia tabularis are highly sensitive to inter-annual climate variability and can be used for paleoclimatic and ecophysiological studies in moist tropical forests.
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