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The mangrove biome is threatened by global environmental changes (including sea level rise, SLR) and anthropogenic disturbances. In this context, understanding the growth dynamics of mangrove species is essential for designing effective management plans for critical mangrove ecosystems such as the Bangladesh Sundarbans. Therefore, this study aims to (1) identify the growth-ring boundaries and tested their periodicity (annual nature) in one of the ecologically important understory mangrove species, Cynometra ramiflora in the Bangladesh Sundarbans, (2) determine the influences of climate and river discharge on radial growth, and (3) examine the influence of habitat variables (e.g., regulators, resources and forest structure) on radial growth. The growth-ring boundaries of C. ramiflora were distinct on the polished wood discs and marked by a layer of flattened fibers mixed with parenchyma. The agreement between individual growth-ring series and chronology statistics enabled us to develop for the first time a 42-year-long chronology spanning from 1979 to 2021. The results indicate that growth rings are annual and could be used for age and growth rate estimations. Monsoonal and annual precipitation enhanced radial growth. Growth was also positively influenced by the amount of river discharge received prior to the onset of growth, particularly during the pre-monsoon. Generalized additive models (GAMs) revealed that among the habitat variables, salinity had a strong negative influence on radial growth of the studied species in the Sundarbans, while tree density and diameter heterogeneity (coefficient of variation, CoV of diameter at breast height) had positive influences. This study revealed that C. ramiflora growth is strongly dependent on soil salinity and highlighted the potential of this approach for improving the prediction of future tree growth and distribution in the face of projected global changes, in particular, SLR. [ABSTRACT FROM AUTHOR]

• We report the first studies of tree growth dynamics of the SDTF of the Marañón valley. • Higher growth rates were found in Cordia iguaguana and Cedrela kuelapensis. • Cedrela kuelapensis presents high growth rates in relation to the congeneric species of the neotropical region. • Populations of endemic species in the area could be mainly of young individuals. Seasonally dry tropical forests (SDTF) currently occupy only 10% of the original area of their natural distribution. In the Marañón river valley, north western of Peru, occurs one of the most important SDTF of the neotropics. It has an endemic woody flora that represent 32% of the species, being threatened by its increasing fragmentation, and the knowledge of the ecology, forestry and conservation of the tree species is scarce. In this context this work presents the result of evaluation of the wood anatomy with emphasis to growth ring analysis, dating trees and stem growth rate determination of four tree species: Anadenanthera colubrina (Vell.) Brenan, Cedrela kuelapensis T.D. Penn. & Daza, Cordia iguaguana Melch. Ex I.M. Johnst., and Esenbeckia cornuta Eng., the last three being endemic and threatened with extinction. Our results determined that Cedrela kuelapensis showed the highest radial growth of the stem in relation to the other congeners of the neotropical region. Lower stem growth was observed for E. cornuta trees, according to the pattern of other tropical species. The results also indicate that populations of C. iguaguana and Esenbeckia cornuta in the zone are mainly composed by young trees exhibiting strong anthropic pressure due to the quality of their timber and, in consequence, more efforts are needed in the management of these resources to guarantee their sustainability. [ABSTRACT FROM AUTHOR]

Abstract Tropical dry forests (TDF) are highly important tropical forest ecosystems. Yet, these forests are highly threatened, usually neglected and only poorly studied. Understanding the long-term influences of environmental conditions on tree growth in these forests is crucial to understand the functioning, carbon dynamics and potential responses to future climate change of these forests. Dendrochronology can be used as a tool to provide these insights but has only scantly been applied in (dry) tropical forests. Here we evaluate the dendrochronological potential of four Caatinga neotropical dry forest tree species – Aspidosperma pyrifolium , Ziziphus joazeiro , Tabebuia aurea , and Libidibia ferrea – collected in two locations in northeastern Brazil (Sergipe state). We provide an anatomical characterization of the ring boundaries for the four species and investigate correlations of their growth with local and regional climatic variables. All four species form annual rings and show high inter-correlation (up to 0.806) and sensitivity (up to 0.565). Growth of all species correlated with local precipitation as well as with sea-surface temperatures in the tropical Atlantic and/or tropical Pacific oceans. We also show teleconnections between growth and the El Niño South Oscillation. The strong dependence of tree on precipitation is worrisome, considering that climate change scenarios forecast increased drought conditions in the Caatinga dry forest. Including more species and expanding dendrochronological studies to more areas would greatly improve our understanding of tree growth and functioning in TDFs. This type of knowledge is essential to assist the conservation, management and restoration of these critical tropical ecosystems. [ABSTRACT FROM AUTHOR]

Water erosion is an important degradation process, which results in loss of soil, reduction in agricultural productivity, and causes severe environmental impact. Dendrogeomorphology has methods in which the structure of the wood of the stem and roots of tree and shrub species affected by sediment deposition or by root exposure is analysed, to establish the chronology of erosive events. The objective of the present work was to describe the modifications and scar formation in Schizolobium parahyba growth rings, attributed to the effect of roots exposure for determining the first year of exposure. The study area presents erosion features, such as gullies, with the consequent exposure of tree roots. The growth rings and the scars formed by the flow of water and soil particles were analysed in cross-sections of exposed roots to date the erosion processes. This paper demonstrates the potential of S. parahyba for dendrogeomorphological studies, validating dendrogeomorphology as a research tool in tropical climate. Scars used for erosion dating in cross-sections have been proven as good indicators of geomorphic processes. The relevance of this work is to become the first attempt in tropical regions to date erosion processes using dendrogeomorphological techniques on exposed roots. [ABSTRACT FROM AUTHOR]

Tundra shrubs are slow-growing species limited by low air temperature and scarce nutrient availability. However, shrub expansion has been widely observed in the Arctic during the last decades and attributed to climate warming. Shift in shrub growth, wood structure and abundance affects the surface albedo and permafrost thawing and these changes may feedback to climate. Despite the importance of shrub–climate feedbacks, uncertainties about shrub growth sensitivity to climate remain. Here, we explored the indirect effects of climate warming on shrub growth (vertical and radial), bark thickness, and bark investment in four arctic shrub species. We combined a field experiment addressing two suggested growth drivers – thawing depth and nutrient availability – with dendroecology in a Siberian tundra ecosystem. We used heating cables to increase the thawing depth. To enhance the nutrient availability, we fertilized the surface soil layers. We found that shrub growth was mainly limited by nutrient availability, as indicated by the fertilization treatment effects on shrub growth ring widths. We also found a bark thickness decrease with the combined soil heating and nutrient addition treatment and a negative correlation between bark investment and growth rate for two of the species. These findings suggest that tundra shrubs, especially deciduous species, will grow faster and taller driven by an increasing nutrient availability in the surface soil layers. However, shrubs might become more vulnerable to pests, herbivory, and climate extremes, such as frost or drought events, due to thinner bark and lower bark investment. Using dendroecological approaches in field experiments simulating projected climate scenarios for the Arctic, and an increasing number of study species and locations will reduce uncertainties related to shrub growth sensitivity to climate and other processes driving shrub dynamics. [ABSTRACT FROM AUTHOR]

Albeit the Sundarbans provides protection and livelihood supports to ∼ 7.5 million climate vulnerable coastal people in Bangladesh and India, this sentinel mangrove ecosystem has been threatened by anthropogenic disturbances and rapid environmental changes including sea level rise (SLR). In this context, long-term tree growth data are increasingly essential to understand the effects of environmental changes on mangroves and also to formulate their management plans. In this study, we evaluate the nature and periodicity of growth rings in Xylocarpus granatum , an ecologically important mangrove tree species growing in the Bangladesh Sundarbans. In addition, we analyze the influences of climatic variables (i.e., precipitation and temperature) and river discharge on its radial growth. The results reveal that X. granatum forms distinct growth rings which are marked by a layer of parenchyma band consisting of 1–4 cells. The visual crossdating and the quality of chronology statistics indicate that the growth rings are crossdatable. A site-specific chronology was developed spanning from 1973 to 2020 based on the crossdated samples. The annual nature of X. granatum 's growth rings offer an opportunity to estimate tree age and growth rate. The ring width is influenced by salinity which is regulated mainly by freshwater influx through annual precipitation along with river discharge, particularly in July. This study suggests that growth rings could be used as a proxy in exploring X. granatum 's growth dynamics, especially in relation to environmental changes. • Xylocarpus granatum forms distinct growth rings. • Crossdatable growth rings provide a solid basis for age and growth rate estimation. • Radial growth is mainly influenced by annual precipitation and river discharge in July. [ABSTRACT FROM AUTHOR]

The Leguminosae family is one of the most representative families in the seasonal semidecidual lowland forest, and many of their species have economical and ecological importance, including for the recovery of degraded areas. However, there is still a lack of knowledge about the biology of native species for forest restoration. Tree growth dynamics features, such as increment rates, life expectancy and tree responses to environmental variations can be assessed through tree-ring studies. Therefore, this study aimed to investigate the growth features of Copaifera langsdorffii , Dalbergia nigra , Pterocarpus rohrii , Schizolobium parahyba and Senna multijuga trees in a known age experimental plantation. The study site was located in Espírito Santo State, southeastern Brazil. Stem discs were obtained for anatomical characterization of tree-rings. Wood samples were sectioned and processed following the usual plant anatomy techniques. For macroscopic analysis, samples were polished and analyzed under a stereoscopic microscope. All species showed distinct growth rings with annual periodicity formation. Growth rates, tree size measurements and growth trajectories were established for each species. These features varied even among trees of the same age and species growing under homogeneous conditions. It is noteworthy that growth variation was not related to the species’ ecological group. These data are important to characterize growth behavior of native species in order to subsidize species selection for recovery of degraded areas and economical purposes. [ABSTRACT FROM AUTHOR]

Abstract: Ring diameters and ring number counts were recorded from Calluna stem cross-sections harvested during an N manipulation experiment. The application of dendrochronological methods permitted accurate ageing of shrubs growing in a heathland of known age. Linear regression analyses demonstrated a highly significant association between increasing levels of N input and stem diameter in both watered and droughted plots (droughted in 1997 only). N inputs were identified as the most significant environmental stressor, appearing to speed ageing vis the Calluna growth cycle. Drought sensitivity was noted in the high N treatment plots (120kgNha−1 yr−1) with decreased stem diameters. This may have implications in the response of Calluna growth under current climate change scenarios. [Copyright &y& Elsevier]

Abstract: The dendrochronological characteristics of 52 tree species from the semi-tropical forests of the Yucatán Peninsula were opportunistically explored in a salvage dendrochronological study. The existence of clear growth rings in these trees is a key prerequisite for further studies and a convincing demonstration of the dendrochronological potential of tropical tree species will allow the development of future research programs concerning the ecology of the species and inferences about past environmental changes detected from tree rings. Many aspects of the conservation and management of Yucatec forests should be urgently addressed to aid in the development of improved strategies beyond the scope of more traditional agricultural uses. Development of tree-ring analyses from selected local species can be of substantial assistance in these initiatives. [Copyright &y& Elsevier]

Sustainable forestry requires accurate ecological information such as species composition, growth rates and recruitment dynamics. Tree growth rates are usually obtained through long-term periodic re-measurements of individual trees or through the analysis of tree growth rings in stem cross sections. However, tree growth ring analysis was traditionally thought to be only possible in biomes with strong seasonality such as those found in high latitude temperate regions. A lack of data on the occurrence and characteristics of tree rings in tropical trees may be due to a lack of investigations. Here we characterise the growth rings of 183 tree species from seven forest types across an altitudinal gradient in northern and central Perú at macro- and microscopic levels. A correspondence analysis showed an association between phylogenetic relatedness and the level of distinctiveness in the growth rings. Deciduous species of seasonally dry tropical forests were associated with distinct growth rings and mainly delimited by marginal parenchyma, while indistinct growth rings were associated with evergreen trees from lowland Amazonian and pre-montane wet forests. Additionally, for the first time the presence of growth ring boundaries defined by marginal phloem is reported in two tropical tree species, Gallesia integrifolia (Spreng.) Harms and Vochysia mapirensis Rusby. This contribution represents the most exhaustive record to date of the occurrence and anatomy of growth rings in trees of the Peruvian tropics, which can be used to inform future dendrochronological studies. [ABSTRACT FROM AUTHOR]