Annual Rings Research Articles

Variation of Ba concentration in some plants grown in industrial zone in Türkiye

This study was carried out on Fagus orientalis Lipsky (Oriental beech), Carpinus orientalis (Oriental hornbeam), and Quercus petraea (Matt.) Liebl. (Sessile oak) species that naturally spread out in the Çaycuma district of Zonguldak province, an industrial area in the northwestern Türkiye. The study aimed to determine the annual changes in barium (Ba) concentrations in the annual rings of the wood of the species. Moreover, Ba concentrations in the inner and outer bark were compared with the concentration in the wood, and changes in Ba concentration were determined by years and directions. As a result, the lowest mean Ba concentrations were found in hornbeam for all organs, whereas the highest values in the inner bark (944134 ppb) and wood (46996 ppb) were found in beech. The highest values in the outer bark were found in oak with 927482 ppb. For the three species, the values obtained on the outer side of the outer bark were higher. The study showed that all three species are useful in monitoring the changes in concentrations and the pollution of Ba in the air and can be used for this purpose. However, the most suitable species that can be used to reduce Ba concentration is Fagus orientalis, which has the highest Ba storage ability in the wood part.

The feasibility of using annual rings to monitor changes in boron concentrations in air

Boron is one of the most important elements on the agenda in recent years, both because it is a micronutrient for plants and because it is used in more than 250 fields in industry. Due to its intensive use and the continuous expansion of these areas of use, the concentrations of boron, which is produced more and more, are constantly increasing in receiving environments. However, boron, one of the important heavy metals, can cause significant health problems when inhaled from the air and taken into the human body. Therefore, monitoring the changes in boron concentration in the air is of great importance. In this study, the change of boron concentration in Pinus pinaster, Cupressus arizonica, Picea orientalis, Cedrus atlantica and Pseudotsuga menziesii species growing in Düzce, which is among the 5 most polluted cities in Europe, was examined on the basis of species, organ, direction and period in the last 40 years. The results of the study generally showed that boron concentrations did not change significantly on the basis of direction and year interval. Similarly, boron concentration in wood did not change significantly by species, whereas the change in boron concentration in bark was found to be statistically significant. According to the mean values, the lowest values were obtained in P. menziesii and the highest values were obtained in C. arizonica.

On the biology of the alien Red Sea goatfish, Parupeneus forsskali (Fourmanoir & Guézé, 1976) in the Aegean Sea, eastern Mediterranean

ABSTRACT The alien Red Sea goatfish (Parupeneus forsskali) was recently reported in the Mediterranean Sea, as a species that migrated two decades ago through the Suez Canal. In this work, efforts are being made to fill knowledge gaps on its biology, through information based on 131 Red Sea goatfish specimens collected from commercial fishing vessels in the south-eastern coasts of the Aegean Sea, Greece (Eastern Mediterranean). The largest specimen examined measured 26 cm in total length (Lmax), while otolith annual ring determination showed that the maximum recorded age was 4 years. The Von Bertalanffy growth function parameters were estimated as follows: L∞ = 32.44 cm, Κ = 0.31 y−1 and t0 = −0.08 y. The diet of the specimens was dominated by Decapoda and Amphipoda (IRI = 66%) with an estimated trophic level of 3.58 (±0.53), characterizing the species as carnivorous with preference for Crustacea prey. Length (Lm) and age (tm) at maturity were estimated to be 19.6 cm and 2.8 years, respectively. The species exhibited larger reproductive load (Lm/Lmax) in the non-native regions compared with its native distribution in the non-native regions compared with its native distribution. In conclusion, further research is required in order to elucidate differences of the species’ life-history traits between its native and non-native distribution.

Age of heartwood initiation in trunks of young Pinus sylvestris L. trees in the taiga zone

Summary This work is part of a project investigating the heartwood formation process in Scots pine. Despite the economic and ecological importance of pine heartwood (HW), the process of its formation in many respects remains poorly understood. Scientists believe that HW formation in Scots pine begins at 9–20 years, however, systematic studies of HW initiation age in this species have not previously been conducted. Samples were collected from 105 P. sylvestris trees aged 10 to 25 years, growing in the middle and northern taiga subzones, as well as on the border of the northern taiga subzone with the tundra. Samples were taken at the trunk base according to a single technique and processed using two biochemical (peroxidase activity, pinosylvin presence) and two anatomical markers (presence of extractives on the tracheid pit membranes, nuclei disappearance) characterizing different events during HW formation. Biochemical markers showed an overestimation in the number of HW annual rings compared with HW determination based on anatomical criteria by 1–3 years, on average. Attempts to detect peroxidase activity showed a negative result in the inner sapwood annual ring, while detectable pinosylvin accumulation occurred in the transition zone (TZ). We have detected for the first time true HW (without living cells) in Scots pine samples with a cambial age (CA) of 15–17 years. The number of growth rings in TZ and HW in young trees depended on growth conditions. These results are important for understanding the mechanisms of HW formation and developing realistic models of this process, including changing climate conditions.

Radial cracks in Castanopsis hystrix wood and its dimensional stability improvement by resin-impregnated modification

Abstract This study investigated the characteristics of radial cracks in Castanopsis hystrix wood and evaluated its dimensional stability after impregnation with low-molecular-weight polyacrylate (PA), melamine-urea-glyoxal (MUG), and melamine-urea-formaldehyde (MUF) resins. The physical properties were examined by dimensional stability measurements, dynamic vapor sorption (DVS) analysis, and scanning electron microscopy (SEM). The results showed that radial cracks were easily produced in the transverse section of untreated wood during drying. The surfaces of the radial cracks exhibited an even and clean structure without fluffs on the pair of surfaces, and cracks spanned 4–5 annual rings. The resin-impregnated wood showed no radial cracks on its transverse surface. C. hystrix wood modified with MUG and MUF exhibited a higher weight percentage gain (WPG) than wood modified with the same concentration of PA resin. The resin-impregnated C. hystrix wood also showed reduced anisotropy and improved dimensional stability. The SEM images of the modified wood showed that the wood pits and cells were filled with resin, while the cell wall surfaces were covered with a layer of resin.

Development of Spatiotemporal Whole-Stem Models for Estimating End-Product-Based Fibre Attribute Determinates for Jack Pine and Red Pine

The objective of this study was to develop spatiotemporal whole-stem wood quality prediction models for a suite of end-product-based fibre attribute determinates for jack pine (Pinus banksiana Lamb.) and red pine (Pinus resinosa Aiton): specifically, for wood density (Wd), microfibril angle (Ma), modulus of elasticity (Me), fibre coarseness (Co), tracheid wall thickness (Wt), tracheid radial diameter (Dr), tracheid tangential diameter (Dt), and specific surface area (Sa). Procedurally, these attributes were determined for each annual ring within pith-to-bark xylem sequences extracted from 610 jack pine and 223 red pine cross-sectional disks positioned throughout the main stem of 61 jack pine and 54 red pine sample trees growing within even-aged monospecific stands in central Canada. Deploying a block cross-validation-like approach in order to reduce serial data dependency and enable predictive performance assessments, species-specific calibration and validation data subsets consisting of cumulative moving average values were systematically generated from the 27,820 jack pine and 11,291 red pine attribute-specific annual ring values. Graphical, correlation, regression and validation analyses were used to specify, parameterize and assess the predictive performance of tertiary-level (ring-disk-tree) hierarchical mixed-effects whole-stem equations for each attribute by species. As a result, the jack pine equations explained 46, 66, 74, 63, 59, 72, 42 and 48% of the variation in Wd, Ma, Me, Co, Wt, Dr, Dt and Sa, respectively. The red pine equations explained slightly higher levels of variation except for Me: 50, 71, 31, 83, 72, 78, 56 and 71% of the variation in Wd, Ma, Me, Co, Wt, Dr, Dt and Sa, respectively. Graphical assessments and statistical metrics related to attribute and species-specific residual error patterns and goodness-of-fit, lack-of-fit and predictive error metrics, revealed an absence of systematic bias, misspecification or aberrant predictive performance. Consequently, the resultant parameterized models were acknowledged as acceptable functional descriptors of the intrinsic spatiotemporal cumulative developmental patterns of the studied end-product fibre attribute determinates, for these two pine species. Although predicted development patterns were similar between the species with the greatest degree of nonlinearity occurring before a cambial age of approximately 30 years, irrespective of attribute, jack pine exhibited a greater degree of nonlinearity in the Wd and Dt developmental trajectories, whereas red pine exhibited a greater degree of nonlinearity in the Ma, Me, Co, Wt, Dr and Sa developmental trajectories. Potential biomechanical linkages underlying the observed attribute distribution patterns, as well as the potential utility of the models in forest management, are also discussed.

Bending and torsion induced stresses in cylindrically orthotropic and inhomogeneous timber beams

The structural design of timber beams subject to bending often relies on the application of the simple Euler–Bernoulli beam theory. However, the simplistic formulas for stress calculations overlook the inherent characteristics of the wood material and the true distribution of the annual rings within the cross-sectional area. This paper introduces a method for determining all six stress components for a cantilever-type beam that is subjected to concentrated end loads. The method considers an inhomogeneous cross-section and employs cylindrically orthotropic material properties. Notably, this approach does not necessitate prior knowledge of elastic and shear centres. It is founded on the formulation of a displacement field incorporating unknown in-plane distortion and warping functions. These are then solved through a straightforward finite element procedure. The efficacy of the method is validated by a series of numerical examples that align with analytical results. Furthermore, a benchmark example for cylindrically orthotropic cross-sections is proposed. As a practical demonstration, an analysis is performed on a real sawn timber cross-section with material parameters representative of Norway spruce. The findings reveal significant disparities in the maximum stresses when compared to conventional engineering approaches. In this specific instance, the maximum longitudinal normal stress resulting from bending is approximately 20 % higher than the outcomes of typical engineering methods. This emphasizes the critical role played by the actual distribution of annual rings across the specific beam cross-section.

Comparing stem growth of strip-bark and whole-bark growth morphologies in a subarctic conifer (Pinus banksiana), Yellowknife, Northwest Territories

Generally, organisms living near the periphery of their range experience increased environmental stress compared to individuals of the same species growing at the core of their geographic distribution. The greater environmental stress at the ecological limits of a species distribution normally leads to greater sensitivity to growth-limiting factors. For some tree species, this can lead to the development of unique growth morphologies such as strip-bark or partial cambial dieback. Previous studies have concluded that the growth differences induced by CO2 fertilization effects in high elevation strip-bark trees makes them unsuitable for climate reconstructions. However, comparisons of strip-bark and whole-bark growth morphologies at high latitude and low elevation sites are limited. This study compares the growth of strip-bark and whole-bark jack pine (Pinus banksiana Lamb.) trees near Yellowknife, Canada. Annual ring widths from trees of each morphological type were measured, and the results indicate the growth of the two populations are statistically different from one another prior to the late 19th century. After the late 19th century, growth of the two populations remains statistically different, but the average mean growth of strip-bark trees increases 44% after 1891 while average mean growth of whole-bark trees decreases nearly 11%. Climate sensitivity of the two populations was tested using monthly and seasonal climate indices from 1943 to 2015 and results indicate the two populations share similar responses to climate. The results of this research suggest these strip-bark and whole-bark trees share similar climate-growth relations at inter-annual timescales, however, their growth trends diverge at decadal to centennial timescales. The timing of cambial dieback was dated to a short time interval in the early 19th century which coincided with a period of cool summer temperatures across the northern hemisphere. Increased growth in strip-bark trees after ∼1891 could be related to CO2 fertilization effects, although further studies into intrinsic water use efficiency would be helpful in assessing this possibility more accurately.

Bark wounding triggers gradual embolism spreading in two diffuse-porous tree species.

Xylem transport is essential for the growth, development and survival of vascular plants. Bark wounding may increase the risk of xylem transport failure by tension-driven embolism. However, the consequences of bark wounding for xylem transport are poorly understood. Here, we examined the impacts of the bark wounding on embolism formation, leaf water potential and gas exchange in the terminal branches of two diffuse-porous tree species (Acer platanoides L. and Prunus avium L.). The effects of bark removal were examined on field-grown mature trees exposed to increased evaporative demands on a short-term and longer-term basis (6h vs 6 days after bark wounding). Bark removal of 30% of branch circumference had a limited effect on the xylem hydraulic conductivity when embolized vessels were typically restricted to the last annual ring near the bark wound. Over the 6-day exposure, the non-conductive xylem area had significantly increased in the xylem tissue underneath the bark wound (from 22-29% to 51-52% of the last annual ring area in the bark wound zone), pointing to gradual yet relatively limited embolism spreading to deeper xylem layers over time. In both species, the bark removal tended to result in a small but non-significant increase in the percent loss of hydraulic conductivity compared with control intact branches 6 days after bark wounding (from 6 to 8-10% in both species). The bark wounding had no significant effects on midday leaf water potential, CO2 assimilation rates, stomatal conductance and water-use efficiency of the leaves of the current-year shoot, possibly due to limited impacts on xylem transport. The results of this study demonstrate that bark wounding induces limited but gradual embolism spreading. However, the impacts of bark wounding may not significantly limit water delivery to distal organs and leaf gas exchange at the scale of several days.

Quantitative wood anatomy and stable carbon isotopes indicate pronounced drought exposure of Scots pine when growing at the forest edge

Climate change poses a major threat to global forest ecosystems. In particular, rising temperatures and prolonged drought spells have led to increased rates of forest decline and dieback in recent decades. Under this framework, forest edges are particularly prone to drought-induced decline since they are characterized by warmer and drier micro-climatic conditions amplifying impacts of drought on tree growth and survival. Previous research indicated that forest-edge Scots pine trees have a higher growth sensitivity to water availability compared to the forest interior with consequent reduction of canopy greenness (remotely sensed NDVI) and higher mortality rates. Yet, the underlying physiological mechanisms remain largely unknown. Here, we address this knowledge gap by comparing stable carbon isotope signatures and wood anatomical traits in annual rings of trees growing at the forest edge vs. the forest interior and between trees that either survived or died during the extreme drought of 2015. Our analyses suggest that the exposure to drought of forest-edge Scots pine likely results in a reduction of stomatal conductance, as reflected by a higher δ13C of stem wood, thinner cell walls, and lower mean ring density. Moreover, we found dead trees to feature larger mean hydraulic lumen diameters and a lower cell-wall reinforcement, indicating a higher risk to suffer from cavitation. In conclusion, the typically drier micro-climatic conditions at the forest edge seem to have triggered a larger reduction of stomatal conductance of Scots pine trees, resulting in a lower carbon availability and significantly altered wood anatomical properties under an increasingly drier climate.

Historical reconstruction of the invasions of four non-native tree species at local scale: a detective work on Ailanthus altissima, Celtis occidentalis, Prunus serotina and Acer negundo

Reconstructing the history (spatio-temporal patterns) of biological invasions at a small spatial scale is challenging, notably because the required data are often not available in sufficient quantity and quality. In this study, we present a mixed approach using six different data sources to explore the spreading history of four non-native invasive tree species, Ailanthus altissima, Celtis occidentalis, Prunus serotina and Acer negundo in a high conservation value foreststeppe habitat with an area of 1000 ha (Peszér Forest, Central Hungary). We carried out a literature search, compiled all the archived and currently valid data of the National Forestry Database (NFD) in a GIS database, conducted a full-coverage field survey, mapped all the large/old tree specimens and carried out annual ring counts, performed a hotspot analysis on the abundance data provided by the field survey and gathered local knowledge. Each of these approaches proved indispensable and their complementary use made it possible to reconstruct the invasion history of all four tree species. According to the available source literature, P. serotina was first planted in the area in 1937 and the first known occurrence of A. altissima could also be traced back to the 1930s. The examination of large specimens of C. occidentalis and querying the NFD for data related to A. negundo provided evidence that these species have been present in the area since at least the 1940s. However, based on the NFD and local knowledge, it is certain that the rapid expansion of the four tree species occurred simultaneously and only around the turn of the millennium, with a lag of at least 60-70 years. The exploration of local knowledge revealed three possible explanations, which interestingly also coincided in time. With the change in the political regime, the intensity of forest use started to decrease in the 1990s, the population of game was drastically reduced at the end of the decade and droughts became more frequent from 2000 onwards. The field survey clearly showed that these tree species were 2-3 times more prevalent and abundant than the relevant NFD data indicated. Finally, the primary hotspots of A. altissima and A. negundo overlapped with the locations of their first known occurrences, while in the case of C. occidentalis and P. serotina, they did not. However, local knowledge revealed that the former two had been ignored since at least the 1950s, while the latter two were occasionally planted until the 1990s. It is likely that the primary hotspots of C. occidentalis and P. serotina indicate the locations of these undocumented plantations.

Current increment of ecosystem services in permanent sample plots within the forest stands of the Feofania park-monument

Despite the fact that forests in nature conservation areas are of mature and over-mature age, they have a leading role in the production of ecosystem services, in particular in ensuring biodiversity. In the typical sense, at the mature and over-mature age of stands, the growth of live biomass and carbon sequestration almost stops, and the death of trees leads to a negative change in the stock. The purpose of the study is to substantiate the ability of over-mature forests to accumulate live biomass under the condition of the formation of multi-tiered and different-age stands. The research was conducted on four permanent sample plots of the Feofania park-monument, which were established in 2016 and 2017. The method of approximate mensuration was used to study the current growth of ecosystem services. The method of dendrochronology was used to analyse annual rings. The age range of experimental stands is between 80 and 180 years. Experimental stands of all sample plots are characterized by high-level productivity, compared to model data on the productivity of stands in Ukraine and the European part of Eurasia. According to the results of the research, it was established that the biggest current increment of ecosystem services is formed in the uneven-aged stand with the centuries-old common oak trees of the overstory. The results of the research can be used in practice for the management of nature conservation areas and improvement of the management of over-mature forests

No evidence that coring affects tree growth or mortality in three common European temperate forest tree species

Tree cores are a highly valuable scientific resource. Annual growth ring data can, for example, improve our understanding of climate change impacts and effects of environmental pollution, allow for better annual estimations of tree growth patterns and carbon storage, and help quantify dynamics and changes in forest ecosystems. The value of coring trees for research has been weighted against concerns around the potential harm coring might cause to trees. To date, there is indeed limited research accurately quantifying the potential effects of coring on tree growth and only a handful of studies assessing its influence on mortality. Consequently, many European long-term forest inventorying and monitoring programs are concerned that tree coring might bias the repeated tree measurements in permanent plots, which they rely on for assessments of states and changes of forests. In this study, we assessed the effects of tree coring on the growth and mortality of three widespread European tree species approximately 10 years after they were cored. We used repeated tree measurements from permanent research sites in Switzerland and Ukraine. In Switzerland, we assessed 35 cored and 159 uncored Norway spruce (Picea abies) trees as well as 147 cored and 332 uncored silver fir (Abies alba) trees. In Ukraine, we assessed 348 cored and 6′611 uncored European beech (Fagus sylvatica) trees. We found no statistical evidence that coring negatively affected the growth or mortality of the three tree species assessed. Although we cannot rule out subtle effects on tree health and wood quality, our findings do not provide any evidence that coring affects or biases repeated measurements (such as DBH measures and recording of mortality) performed on the investigated tree species. Tree coring could therefore be considered more often for routine incorporation, particularly in long-term forest inventorying and monitoring programs and initiatives.

SEASONAL CHEMICAL STRUCTURE VARIABILITY IN BETULA TORTUOSA LEDEB. TREE RINGS IN ALPINE FOREST-TUNDRA OF KUZNETSK ALA TAU MOUNTAINS

Woody vegetation growth conditions have marked effects on hemicellulose, cellulose and lignin formation. In this study, we analyzed the climatic responses of these major cell wall polymers in Betula tortuosa. We studied 35 annual rings (1980–2015) of Betula Tortuosa Ledeb. trees growing in the alpine forest-tundra of Kuznetsk Ala Tau using and pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Our analysis of the correlation of the resulting spectra and Py-GC/MS values with mean air temperature and precipitation showed that the polymeric composition of Betula Tortuosa Ledeb. was mainly determined by June-August climate. The major factor limiting the development of the “unique” cell wall polymer composition of Betula Tortuosa Ledeb. found in alpine forest-tundra of Kuznetsk Ala Tau was a deficit of heat. At the end of the growing season, precipitation had largely a negative impact on polymer formation in Betula Tortuosa Ledeb. cell walls. We believe that Py-GC/MS is an effective approach to quantifying the consequences of current climate trends for Siberian forest ecosystems.

The formation of xylem tissues and secondary cell walls is diminished by severe and consecutive insect defoliation.

Insect defoliation causes unusual wood structures in forest trees. However, the characteristics of the unusual wood structure of hardwoods remain unclear. The aim of this study was to clarify the characteristics of the wood structure in trunks produced under severe insect defoliation in Betula maximowicziana trees. Samples from the trunks were taken from two sites (Naie and Furano) in central Hokkaido where insect defoliation by Caligula japonica occurred during 2006-2012. The cross-dating and microscopic observations with histochemical staining were done. White rings with thin-walled wood fibers and drastic reduction in annual ring width in the subsequent year were observed in both samples. From these results, the formation year of white rings were determined and severe defoliation was confirmed to trigger white ring formation. The characteristics may prove useful for the detection of the formation year of white rings. Then, we clarified the cell morphology of wood fibers in the white rings. Scanning electron microscopy and histochemical analyses indicated that the thickness of the S2 layer of wood fibers decreased, but xylan and lignin were still deposited in the cell walls of wood fibers in a white ring. However, the cell-wall thickness of wood fibers recovered after defoliation period. Our results suggest that B. maximowicziana would respond to a temporary lack of carbon due to insect defoliation by regulating the thickness of the wood-fiber S2 layer. For B. maximowicziana, insect defoliation during the late growing season has serious deleterious effects on wood formation and radial growth. This article is protected by copyright. All rights reserved.

Anatomy of xylem and phloem in stems and roots of Populus sibirica and Ulmus pumila from semi-arid steppe in Mongolia

The present study focuses on the cambium and the anatomy of secondary tissues (xylem – wood and phloem) of Siberian poplar (Populus sibirica) and Siberian elm (Ulmus pumila) grown in a plantation in the semi-arid Mongolian steppe. Stem and root microcores from both species were collected and subsequently processed to obtain cross-sections for light microscopy by paraffin embedding, sectioning with a rotary microtome, and staining with safranin and astra blue. The results present the anatomy of the secondary xylem and phloem of stems and roots of both species, along with the characteristics of the youngest xylem and phloem annual rings. We discuss the critical aspects which need to be considered when using the microcoring methodology, along with the need for further studies on wood and phloem formation of less-commonly studied tree species and their characteristics when grown in semi-arid environments.

Proof of concept to characterize historical heavy-metal concentrations in atmosphere in North Turkey: determining the variations of Ni, Co, and Mn concentrations in 180-year-old Corylus colurna L. (Turkish hazelnut) annual rings

Proof of concept to characterize historical heavy-metal concentrations in atmosphere in North Turkey: determining the variations of Ni, Co, and Mn concentrations in 180-year-old Corylus colurna L. (Turkish hazelnut) annual rings

Analysis of Radial Growth Dynamics of Pinus Nigra Subsp. Pallasiana (Lamb.) Holmboe in Different Parts of the Slope Profile

The results of the research of radial growth of Pinus nigra trees growing in the foothill-forest-steppe zone (in Belogorosk district) with continental climate type of the Crimean Peninsula are presented. The research was con[1]ducted to evaluate the influence of the location of the growth site on the local slope on the total width of the annual ring. Geomorphologically, the sampling points were located along the profile of a gentle convex slope of eastern exposure. Wood samples were collected at sites within the lower, middle and watershed parts of the slope, as well as at the top of the Biyuk-Karasu River watershed. Generalised tree-ring chronologies were obtained for each part of the slope, the average age of the chronologies being 50 years. As a result of the research, a synchronism in growth dynamics of trees growing in the lower part of the slope and in the watershed was established; the radial growth of Pinus nigra trees in the middle parts of the slope reacts the earliest to the influence of environmental factors. The reaction lag of radial growth in the watershed part of the slope is about 11 years. Analysis of the constructed chronologies shows that over the past 50 years, the radial growth is comparable to the dynamics of meteorological parameters. The analysis of correlations of the obtained chronologies with the values of average monthly air temperatures and annual precipitation according to the data of the Simferopol meteorological station was carried out. For the lower and middle parts of the slope, as well as for the watershed, the amount of precipitation is more significant than air temperature. Correlations have been established between the radial growth index of the lower and middle parts of the slope, as well as watershed and the sum of precipitation in May, and the summer months of both the current and previous years. For Pinusnigra trees growing on the watershed parts of the slope, air temperatures of summer months of the current and previous year are more significant. The established close relationship can be used to reconstruct climatic conditions of Pinus nigra trees.

Relative Age and Growth of Indian Major Carp, <i>Cirrhinus mrigala</i>, from Peninsular Rivers of India

The age of Indian major carp, Cirrhinus mrigala (Hamilton, 1822) was determined from 208 specimens from five peninsular rivers (Mahanadi, Godavari, Kaveri, Narmada and Mahi) of India by observing the annual rings in scale. Using length-frequency method and scale study, it was found that only River Mahi holds 6+ year class of C. mrigala stocks. A strong linear relationship was found between fish length and scale radius of this species in all the riverine populations, with significant correlation coefficient. The first growth ring was found at an average length of 27.86, 28.86, 37.22, 26.77 and 25.59 cm in specimens from Mahanadi, Godavari, Kaveri, Narmada and Mahi, respectively. It is evident from our result that the fishes exhibited rapid growth rate during the first two years of their age but later, growth was moderate. Growth rate decreased successively at higher ages.

Climate variability impacts on growth of African grape (Lannea microcarpa Engl & K. Krause) in West Africa

Lannea microcarpa is a deciduous tree with high socio-economic value in West African agroforestry systems. While climate-growth relationships remain unknown, this species is exposed to climate extremes. Knowledge of its response to climate variations is needed for its sustainable management. Therefore, the present study aimed to examine the growth of Lannea microcarpa in two climatic zones in West Africa (Sudanian zone of Mali and Sudano-Sahelian zone of Burkina Faso) using standard dendrochronological methods. In both sites, Lannea microcarpa forms distinct growth ring-boundaries characterized by a wider band with more parenchyma cell rows and is also marked by its solitary vessels. The two standard chronologies developed were significantly correlated with the precipitation records in both Burkina Faso (r2 = 0.41, n = 30 years, p < 0.01) and Mali (r2 =0.60, n = 53 years, p < 0.001). Furthermore, a strong relationship between major seasonal precipitation (between June and September) and residual chronology was observed in Burkina Faso (r2 = 0.51, n = 28 years, p < 0.01) and Mali (r2 = 0.65, n = 52 years, p < 0.001). The formation of annual growth rings is clearly influenced by climate variability, but not all variance is accounted for. The insignificant correlation between the chronologies of the two regions may be due to various factors, including differences in climate factors and soil conditions influencing buffered water availability. Similar studies on other tree species in West Africa will be useful.