The 2012–2016 California drought was the most severe in the state’s recorded history, contributing to the death of millions of trees. Through sampling 54 (0.25 ha) plots in northern California and ...employing standard dendrochronological techniques this study compared tree mortality and regeneration patterns before, during, and after California’s recent record-setting drought in both montane and costal environments. This study evaluated 1) the influence of habitat and competitive covariates on mortality and regeneration trends using ridge regression analysis; and 2) tree death and seedling/sapling establishment dates using dendrochronology and Superposed Epoch Analysis to explore the influence of climate on forest demographics. Results showed two trends related to climatic patterns in montane environments: (1) years with high rates of mortality were positively associated with climatic water deficit (CWD) in the 1–2 years preceding and during tree death dates; and (2) regeneration dates were significantly associated with below-average CWD in the preceding year. In montane sites, pre-drought mortality was greater at wet sites than dry sites, and drought-related mortality was positively related to canopy openness. In coastal environments, drought-related tree mortality was positively associated with maximum temperature and topographic position (e.g., greater on upper slope sites). Drought-related tree mortality occurred primarily in trees smaller than 40 cm diameter at breast height (DBH, 1.37 m) in montane forests, and exclusively in trees 80 cm DBH or smaller in coastal environments. Our findings also indicate that current demographic trends will likely reduce forest diversity in the future, especially in montane environments. For example, in montane environments mortality was greater in white pine species (Pinus lambertiana and P. monticola) than other species and regeneration was weighted towards advanced regeneration of shade-tolerant fir (Abies) species (median age of 34 years). These findings highlight the effects of fire exclusion, and the need for targeted management, including reducing tree density and returning fire process, aimed at decreasing drought related mortality, and increasing regeneration of shade-intolerant species (e.g., pines). Management should also preferentially retain medium to large trees, which demonstrated less vulnerability to mortality, to enhance the resilience and diversity of northern California forests.
•Montane tree mortality was associated with high climatic water deficit (CWD).•Montane tree regeneration was associated with low CWD in the preceding year.•Drought-related mortality was more frequent in small trees than large trees.•Mortality was highest in Pinus; regeneration was dominated by shade-tolerant taxa.
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.
This is a datapaper including microscopically measured data of annual ring widths from the Mediterranean-alpine shrub species Cytisus galianoi (Sierra Nevada, Spain). The dataset will be updated with ...future measurements.
Here, we present a datapaper containing microscopically measured data of annual ring widths in the arctic-alpine dwarf-shrub species Salix herbacea (central Norway). The dataset will be updated with ...future measurements.
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