Tree Productivity Research Articles

Comparative Analysis of Branch Diameter Variations in ’Cherry Gala’ Apple Trees

This study presents a detailed characterization of the branch architecture of the ’Cherry Gala’ apple variety, conducted in Azrou region, Morocco, with a focus on two distinct stages of growth. The main objective was to measure and analyze the diameters at the base and extremity of various architectural components, including the trunk, scaffold branches, and specific fruit-bearing structures like dard, bourse, and fruiting spurs. Our analysis revealed that the variation in diameter at the base was not significantly different between stages for fruiting spurs and dard, but was significant for bourse. Conversely, the diameter at the extremity showed significant variation for fruiting spurs and bourse, but not for dard. Additionally, the study found a predominance of bearing branches, which constituted 44% of the total. However, crowned twigs, simple twigs, and woody twigs, representing only 5% of the branches, were excluded from the analysis due to their low numbers. The study also established significant correlations between the base and extremity diameters across different types of branches. These findings provide valuable insights into the structural dynamics of ’Cherry Gala’ apple trees, which could be instrumental in optimizing orchard management practices and enhancing yield predictions. Future research could benefit from incorporating these structural aspects with fruit production data for a more holistic understanding of apple tree growth and productivity

Prediction of essential oil content in C. sintoc Leaves based on the direction of vegetation slope in Mount Ciremai National Park using ANFIS Artificial Neural Network.

C. sintoc is a plant that has a high essential oil content. Essential oils have many health benefits. Mount Ciremai National Park is an area that has abundant vegetation, especially C. sintoc. The purpose of this study was to predict the volume of oil contained in the leaves of C. sintoc based on its growing location in Mount Ciremai National Park (TNGC), West Java. Sampling was carried out in two stages, namely field samples and laboratory samples. Field samples with a single plot measuring 20 x 20 meters. Extraction of laboratory samples by steam distillation method. Data analysis using ANFIS method to predict the volume of essential oil. The results showed that the volume of essential oil in the leaves was largest on the western slope (1,96 ml), northern slope (2,01 ml), eastern slope (1,55 ml) and southern slope (1,37 ml) while the essential oil yield of extract oil in the leaves is found on the western slope (0,08%), northern slope (0,07 %), eastern slope (0,06 %) and southern slope (0,04), On the western slope (1,82 ml), northern slope (1,73 ml). The ANFIS analysis results showed a prediction accuracy of 90,99% with the highest tree productivity when C. sintoc BL grows at an altitude of 650-700 meters above sea level, tree diameter of 42 cm, height of 12 m, growing on sand-textured land and at a humidity of 75 and at a growing temperature range of 25-270C. The value of essential oil production volume is influenced by each variable such as tree diameter, tree height, soil texture, altitude, temperature and humidity.

The role of agroforestry in farmers’ strategies and its contribution to the well-being of rural people in Timor-Leste

ABSTRACT Many countries have integrated agroforestry into their sustainable development policies, particularly in Southeast Asia. In Timor-Leste, the national strategy to promote agroforestry has adopted a modern, technique-oriented approach focused on crop rotation, intercropping and agro-silvo-pasture. In so doing, it has largely overlooked the pre-existence, diversity and performance of traditional agroforestry systems (AFS). The data collected in seven villages located in four districts of the eastern municipalities of Timor-Leste identified five common AFS: home garden, crop field and fallow, young agroforest, forest garden and silvopastoralism. The combined use of the customary AFS by rural households depends on the households’ ability to access the four types of capital (land, financial, labour and social) underpinning their development strategies. Four rural household archetypes were therefore distinguished. Six farming strategies used by these archetypes were identified: cattle specialisation, palm and tree product harvesting, crop intensification, diversification of off-farm and on-farm income, abandonment of farming, and survival. Each of these farming strategies combine certain customary AFS. The diversity and complexity of AFS require a better description of how they function and a better understanding of how they fit into the heterogeneous development strategies of rural households before actions are considered to improve their performance.

Recovery of Coconut Trees from Scale Insect Infestation with Salt and Trichoderma Microbial Inoculant (TMI)

This study showed the role of Trichoderma Microbial Inoculant (TMI) and salt in the fast recovery of mature coconut trees damaged by coconut scale insect, Aspidiotus rigidus Reyne, and in the growth of coconut seedlings. Four treatments with three replicates were laid out in a randomized complete block design. Treatments made were: T0 with 0 fertilizer, 0 TMI; T1 with full dose N, P, K fertilizers, NaCl, 0 TMI; T2 with ½ dose fertilizers + NaCl, + TMI; and T3 with NaCl + TMI. Fertilizers and salt were split delivered in T1. Ten 1-m tall coconut seedlings (Laguna Tall Variety) per replicate treatment were interspersed with the mature trees in each block. About 25 g TMI per tree and 15 g TMI per seedling were applied together with fertilizers. Numbers of green, yellow, and brown leaves, inflorescences, and fruits produced per mature tree were monitored for 27 months. New and mature green leaves were counted as measure of coconut seedling growth. Mature trees in T3 had significantly higher number of green leaves and fruits compared to other treatments. T3 seedlings had significantly higher number of mature green leaves than those of other treatments. Both mature trees and seedlings in T3 exhibited the fastest growth. These results highlighted the importance of salt and TMI for productivity of coconut trees and seedlings.

Long-Term Monitoring Studies of the Mycorrhizal Colonization of Aesculus hippocastanum L. Roots and the Vitality of Soil Microorganisms in Urban and Non-Urban Environments

Stress factors typical in urban environments adversely affect the productivity and vigor of trees and may limit the development of tree roots with associated soil fungi and bacteria. Studies on mycorrhizal symbiosis and the activity of soil microorganisms are important in monitoring the adaptation of trees to urban conditions. We compared the symbiotic activity of arbuscular mycorrhizal fungi (AMF) living in the rhizosphere of mature white chestnut trees (Aesculus hippocastanum L.) in an urban ecosystem at sites with varying degrees of anthropopressure and in a rural area. We used two methods: (1) direct analysis of the root samples, (2) assessment of the colonization of trap plants grown in the soil taken from under selected white horse chestnut trees. The seasonality of mycorrhizal colonization and soil microbial respiration based on the enzyme activity of nonspecific dehydrogenase (DHA) was studied over several growing seasons. The concentrations of macronutrients in the soil from all study sites were in the ranges accepted as normal for the upper soil layer. However, the C/N ratio indicated carbon limitation in the soil at urban and rural study sites. The results showed that arbuscular mycorrhizal fungi indigenous in the rhizosphere of A. hippocastanum developed a functioning mycorrhizal symbiosis at all research sites, including at highly disturbed urban locations, and that the mycorrhizal colonization varied between the study sites and the research term. The trap culture method confirmed the high biological potential of the soil microbial community, including AMF in urban ecosystems, which was comparable to that at the reference site in the rural environment. Soil moisture strongly affected the overall soil microbial vitality. This research showed that the mycorrhizal status of A. hippocastanum is more strongly influenced by climatic conditions and seasonal rhythms of trees than by urban/non-urban locations.

Cold units and their relationship with wheat grain yield in the Yaqui Valley, Sonora, Mexico

Global warming has the potential to cause the reduction of the cold period available during the winter, which may affect the production of wheat and deciduous fruit trees. Wheat requires accumulated cold units (CU) to switch from a vegetative period to a productive one, making the phenological cycle slower and promoting greater productive yield. The objective was to analyze the accumulation of CU and wheat yield during the last five fall-winter agricultural seasons (2018-2019 to 2022-2023) in the Yaqui Valley, Sonora, Mexico. Data of air temperature were obtained from 21 meteorological stations from the network of automatic meteorological stations of the state of Sonora, located in the Yaqui Valley. The number of CU (≤ 10 °C) was calculated for the wheat season (November 15 to April 30) from the years 2018 to 2023, and the grain yield was obtained from the reports by the Agri-Food and Fisheries Information Service. Descriptive statistics of central tendency, dispersion and the Shapiro-Wilk test were performed to determine the normality of the data; also, correlation analysis and the simple linear regression model by least squares were performed. The 2022-23 crop season showed the highest average grain yield (7.79 t ha-1) and the highest average number of CU (882) among the five seasons analyzed. Wheat seasons 2018-2019 and 2019-2020 had an average number of CU lower than 500. The Pearson correlation analysis showed a highly positive correspondence between CU and grain yield. The linear regression model showed that starting from a base of 434 CU, wheat production per hectare would be 5.90 t, and it will increase 214.3 kg for every additional 100 CU.

Analysis of Determining The Cost of Replanting for Smallholder Oil Palm Plantations Using Annuities Model with Python

Palm oil replanting is a necessary activity to enhance the productivity of aging oil palm trees. However, the high costs associated with replanting often create a financial burden for farmers. To address this issue, the study proposes the implementation of a contribution or levy system for smallholder farmers while their oil palm plantations are still productive, which would alleviate the financial burden of replanting. The research methodology employed includes a literature review and primary data collection through a survey of smallholder farmers, with the data being processed to create a mathematical model and simulated using the Python programming language. The results of this study include the development of a mathematical model for the levy and distribution of replanting costs, along with a simulation of the proposed system. This model could help smallholder farmers prepare for replanting costs, enhance the sustainability of palm oil production, and ultimately increase productivity.

KERAGAAN TANAMAN KELAPA SAWIT MENGHASILKAN PADA LAHAN BEKAS TAMBANG BATUBARA

The research was on ex-coal mining land located in Kintap District, Tanah Laut Regency, South Kalimantan Province, and the oil palm plantation located in Kelumpang Selatan District, Kotabaru Regency, South Kalimantan Province. The increase in palm oil production in Indonesia is followed by increasing in the area of oil palm plantations every year. Arable land is limited, and a ban on opening new land for oil palm plantations affects oil palm companies to utilize existing marginal land for oil palm plantations. The research aims to find out and compare the growth and production of mature oil palm trees planted on ex-coal mining land and original mineral land. The study was conducted from March to April 2023 and used agronomic methods by determining sample blocks and collecting primary and secondary data. That data was obtainable by measuring trees in 2 ex-coal mining blocks and original mineral blocks. Each block consists of 30 sample trees. The data obtained were then analyzed using the t-test at a significance level of 5%. The results showed the stem circumference, number of fronds, and length of fronds on ex-coal mining land were significantly different from the original mineral land, and stem height, number of leaves, petiole width, petiole thickness, and production on ex-coal mining land didn’t show significant differences from the original mineral land.

Wood Material Properties of Forest Fire-Damaged Norway Spruce and Scots Pine for Mechanical Wood Processing in Finland

Due to climate change, the risk of forest fires has increased in Europe, resulting in challenges in the allocation of salvaged wood. We studied the raw material potential for wood products of Norway spruce and Scots pine sawn log trees that remained standing after a large forest fire in Kalajoki, Finland, in July 2021. Eight burned trees, with four reference trees per species, were sampled as standard specimens, and measurements were analyzed with linear mixed models. The effects of fire on the modulus of elasticity and rupture, Brinell hardness, moisture gradient, and color were measured on clear wood specimens of sapwood and heartwood. The wood density, level of fire damage, and height location of a tree were used as additional predictors. The results show some changes in the sapwood material. Spruce wood underwent stronger changes after the fire than pine wood, probably due to spruce wood having a thinner bark and a longer crown. The moisture content decreased in spruce, and the color darkened in both spruce and pine. Changes in the mechanical properties were mostly negligible, but a small increase in the Brinell hardness in spruce and a small decrease in the modulus of rupture in pine were observed. Fresh salvaged wood can be a suitable material for middle-quality and lower-quality wood products. The spread of char and soot into wood and wood processing machinery still limits its usage, especially for spruce.

Assessing Pruning Intensity to Improve the Tea Productivity in Tropical Plantations by Multispectral Image Classification Model Using K-Means Algorithm

Tea (Camellia sinensis) plays a crucial role in the Indonesian economy, but its production has witnessed a decline over the last two years. The majority of tea plantations in Indonesia have historical roots from the Dutch East Indies colonial government, underscoring the importance of monitoring pruning practices in tea plantation management. However, manual monitoring methods prove ineffective, prompting the exploration of precision farming principles using satellite imagery and machine learning to address this challenge. This study was conducted on a 231-hectare tea plantation south of the Tangkuban Perahu Volcano in West Bandung Regency, Indonesia. Sentinel-2B imagery from June to October 2019-2023 was utilized to calculate Soil Adjusted Vegetation Index (SAVI) values and assess tea productivity. Employing the K-Means algorithm, productivity values were grouped, and pruning intensity was categorized into three classes, revealing spatial dynamics influencing tea tree productivity. Our results illustrate distinct spatial patterns of pruning intensity across the 231-hectare tea plantation, identifying three classes: less pruned, moderately intensive pruned, and intensively pruned. We show that proposed model of pruning intensity from K-Means algorithm has overall accuracy of 0.57, with highest precision in less pruned class, while the lowest in moderately intensive pruned class. Notably, consistently higher productivity was observed in less pruned tea trees, while an increase in productivity in intensively pruned trees occurred after the second pruning in 2022. These findings highlight the potential of satellite imagery and machine learning for enhancing precision monitoring in tea plantations, offering a practical approach for long-term plantation management. Emphasizing the significance of pruning strategies, our study suggests that optimizing tea productivity amidst environmental and management challenges is achievable through informed monitoring and strategic pruning practices.

Survey of Phytophthora Diversity Reveals P. abietivora as a Potential Phytophthora Root Rot Pathogen in Québec Christmas Tree Plantations.

Christmas trees are an economically and culturally important ornamental plant in North America. Many microorganisms are pathogens of firs cultivated as Christmas trees. Among those, Phytophthora causes millions of dollars in damage to plantations annually. In Canada, it is unknown which species are responsible for Phytophthora root rot (PRR) of cultivated Abies species. Between 2019 and 2021, soil and root samples were collected from 40 Christmas tree plantations in Québec province. We used soil baiting and direct isolation from unidentified root fragments to assess the diversity of culturable Phytophthora spp. The obtained isolates were identified using a multilocus sequencing and phylogenetic approach. A total of 44 isolates were identified, including eight P. chlamydospora, eight P. abietivora, seven P. gonapodyides, three P. gregata, six P. megasperma, and two P. kelmanii isolates, plus 10 isolates belonging to a previously unknown taxon that is phylogenetically close to P. chlamydospora and P. gonapodyides. Among the known species, P. abietivora was the most prevalent isolated species associated with trees showing aboveground PRR-like symptoms. Pathogenicity trials confirmed the pathogenicity potential of P. abietivora on both Fraser fir and balsam fir seedlings. Our study provides a first snapshot of the Phytophthora diversity in Québec's Christmas tree productions and describes multiple potential first associations between Phytophthora species and Abies balsamea and A. fraseri.[Formula: see text] Copyright © 2024 His Majesty the King in Right of Canada, as represented by the Minister of Natural Resources Canada. This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Nematodes as bioindicators of soil health in different land uses in the São Francisco River Valley, Brazil

Summary Brazilian Caatinga is one of the most diverse, seasonally dry, tropical forests of the world and is threatened by strong land use pressure and poor protection. One way of understanding changes in the soil conditions caused by anthropogenic activities is using the nematode assemblages as potential bioindicators. This study analysed changes in nematode communities in three different types of land use (natural forest-CA, natural area with accumulation of salts-SS, and agricultural growing areas, such as cover crops-CC for cattle and fruit trees-IC) in the Caatinga, in the sub-median region of the São Francisco River Valley (SFRV), Pernambuco, northeastern Brazil. We recorded a total of 63 262 nematode individuals, representing 42 genera, belonging to 23 families. Nematode abundance, diversity and maturity indices were highest in the CC and lowest in the SS. Among the nematode trophic groups, bacterivores, omnivores + predators and plant parasites were significantly affected by type of land use. Different soil properties were related to the differences in taxonomic composition among the natural and agricultural areas, accounting for 26.6% of the total variation. In general, our results indicate that soil salinisation and desertification in the natural areas, as well as soils subjected to cover crops and fruit tree production, significantly influenced the composition of nematode communities in the São Francisco River Valley.

Evaluating the effectiveness of different variable retention harvesting treatments on forest carbon uptake using remote sensing

Variable retention harvesting (VRH) is an ecologically based forest management practice applied to emulate natural post-disturbance residual canopy structure and increase the biodiversity and resilience of a regenerating stand. The pattern and density of canopy retention also influences the productivity, mortality, and carbon (C) sequestration rates of residual trees. In this study, we used high-resolution satellite and drone remote sensing data to evaluate the effect of five different VRH treatments on growth and C uptake of a 90-year-old red pine (Pinus resinosa Ait.) plantation forest in southern Ontario, Canada. The treatments included four different combinations of harvesting intensity residual tree distribution including 33% aggregate retention (33A), 55% aggregate retention (55A), 33% dispersed retention (33D), and 55% dispersed retention (55D) and unharvested control (CN) each replicated four times in 1 ha plots. Satellite- and drone-derived normal difference vegetation index (NDVI) and gross primary productivity (GPP) were estimated for each treatment during the growing seasons from 2010 to 2020. Over this period, observed mean daily NDVI values ranged from 0.25 to 0.86 among treatments, where the 55D treatment consistently showed the highest NDVI values. Overall, the highest mean daily GPP values were observed in the CN treatment, followed by the 55D, 55A, 33D, and 33A treatments. Remote sensing-derived mean annual GPP for the entire 20 ha study site was 1651 ± 89 g C m−2 year−1, with a range of 1407–1864 g C m−2 year−1 from 2010 to 2020. Satellite-derived annual GPP values were linearly related with observed annual GPP (R2 = 0.88, p = 0.032) measured using the eddy covariance technique in an adjacent white pine plantation of similar age and height over the study period. Study results suggested that VRH treatments that create a uniformly dispersed residual canopy retaining more than half of the initial basal area (e.g. 55D) is a viable forest management practice where optimizing forest growth and C uptake is a primary management objective. Our study will help forest managers and researchers to develop methodologies to evaluate the effectiveness of forest management practices, tailor them to achieve climate mitigation and adaptation goals and to develop forest management pathways for nature-based climate solutions.

Features of growth and production processes in own-rootedand grafted cherry plum trees

In 2022-2023, a comparative study of the growth and productivity of own-rootedand grafted cherry plum trees planted in 2020 according to the 5×2 m scheme was conducted at the Federal Horticultural Research Center for Breeding, Agrotechnology and Nursery. The objects of research are plants of the varieties ‘Shatyor’, ‘Zlato Skifov’ and ‘Kubanskaya Kometa’, own-rooted and grafted on clone rootstocks SVG-11-19 and 13-113. Differences in biometric indicators in own-rootedand grafted trees of all studied varieties have been established. The height of trees at the age of 5 years varied depending on the graft -rootstock combination from 2.0 (‘Zlato Skifov’/SVG-11-19) up to 3.1 m (‘Shatyor’/13-113). The height of the own-rootedtrees was 15-20 % less than that of the trees grafted on the rootstock 13- 113. The ‘Kubanskaya Kometa’ and ‘Shatyor’ varieties showed a significant decrease in height when grafted on the SVG-11-19 rootstock. The trees of the ‘Zlato Skifov’ variety (less than 2.1 m) were the weakest in the experiment. Differences in the length of annual increments and leaf area were revealed. The productivity of cherry plum trees in the initial period of fruiting depended both on varietal characteristics and on the method of growing planting material. The most productive variety was a Shatyor with a load yield of more than 11 kg/der. The greatest differences in productivity, depending on the rootstock, were noted in the ‘Kubanskaya Kometa’ variety: from 7.3 to 12.9 kg/der. The average productivity of trees of the ‘Zlato Skifov’ variety did not exceed 5.5 kg/der. The ‘Kubanskaya Kometa’ and ‘Shatyor’ varieties have an advantage in productivity in trees grafted on the SVG-11-19 rootstock compared to own-rootedones. The fruits of own-rootedtrees of all varieties were smaller than those grafted on the rootstock SVG-11-19. To increase the yield of the ‘KubanskayaKometa’ and ‘Shatyor’ varieties, seedlings grafted on the SVG-11-19 rootstock should be used. For a low-growing variety of ‘Zlato Skifov’, the optimal result can be obtained when planting plantings, both with own-rootedseedlings and grafted on rootstock 13-113.

From leaves to the whole tree: Mistletoe effects on the productivity, water relations, and demography of a Neotropical savanna tree

AbstractTrees' responses to mistletoes occur at multiple organization levels (e.g., leaf, individual, population), yet integrating these multi‐scale responses is still challenging. Here, we compared the traits of infected versus uninfected trees over multiple scales, from leaf anatomy and physiology to canopy allometries and individual growth rate and survivorship. We tested the hypotheses that mistletoes lead in the host (1) the production of leaves with a conservative resource‐use strategy, (2) more mechanically stable canopies and (3) reductions in growth and survival probability in the trees they infect. We addressed these hypotheses in the widespread savanna tree Vochysia thyrsoidea and xylem‐tapping mistletoe Psittacanthus robustus in the Brazilian Cerrado, a global biodiversity hotspot. We found that (1) mistletoe infection did not affect key traits associated with resource conservativeness, such as leaf mass per area (LMA) and carbon assimilation rates (A). Likewise, (2) hosts did not increase the mechanical safety of their trunks in response to mistletoe infection since infected and uninfected trees had a similar allometric scaling between height and crown volume against stem diameter. (3) At the population level, both the relative growth rate and survival probability decreased as the number of parasites increased. However, zero growth and a 50% chance of mortality were estimated to occur in a minority of heavily infected trees (>7 and 14 parasites, respectively). Our results challenge the idea that mistletoes have a ubiquitous negative impact on their hosts. We highlight, therefore, the need for clarifying the mechanisms that allow trees to maintain their functioning even in the face of mistletoe parasitism.

Does ash dieback affect the reproductive ecology of Fraxinus excelsior L.?

Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems. The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L. and have a major impact on the quantity and quality of pollen and seeds. In this study, we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022. Inflorescences were collected from 105 trees (pollen production), pollen from 125 trees (pollen viability), and seeds from 53 trees (seed quality) in two seed orchards and in one floodplain forest in southern Germany. Not all parameters were examined at every site every year. The average pollen production per tree was estimated at 471.2 ± 647.9 billion pollen grains. In addition, we found that a high number of inflorescences did not equate to high pollen production per inflorescence. Pollen production of healthy and diseased trees did not differ significantly, although only 47% of severely diseased male trees (vs. 72% for healthy trees) produced flowers. With regards to pollen viability, the TTC test showed an average viability of 73% ± 17%. Overall, there was a slight tendency for diseased trees to have less viable pollen. However, a significant difference could only be calculated for trees in the floodplain forest. The percentage of germinable seeds in 2018 was 38% in the floodplain forest and 57% in one of the seed orchards. The percentage of viable seeds (TTC test) ranged from 17 to 22% in the orchards in 2020. Non-viable seeds were usually heavily infested by insects. In general, seed quality was not significantly different between healthy and diseased trees. Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality. Nevertheless, the fact that hardly any flowering was observed, especially for trees that were seriously affected, suggests a negative effect of ash dieback on reproductive performance. Thus, severely diseased trees will transfer their genes to a smaller extent to the next generation.

Climate-related variation in leaf size and phenology of Betula ermanii in multiple common gardens

ABSTRACT Leaf phenology and properties are the vital traits of productivity and fitness of individual trees. Understanding the climatic conditions associated with the trait variation is essential for evaluation of the tree species’ capacity to face and adapt to environmental change. This study focused on the habits of the tree species in the alpine forests where they are experiencing some of the highest rates of warming under recent climate change. Thus, we examined the climate-related variation in leaf area, specific leaf area (SLA) and the timing of bud break in common gardens of Betula ermanii across a wide latitudinal range, as well as their height that was strongly correlated with leaf traits. Based on analysis of variance, all recorded traits were found to be genetically controlled, and leaf area was most strongly affected by genetic factors. Traits of saplings from higher latitudinal populations included taller height, larger leaf area, larger SLA and earlier bud break. Leaf area of B. ermanii saplings was strongly correlated with the height of the saplings, as taller saplings exhibited larger leaves. Saplings derived from regions with fewer precipitation in summer showed taller height and larger leaves. In contrast, we could not observe significant associations between SLA and timing of bud break, and any climatic variable for two experimental years. Increasing earliness of bud break of B. ermanii with increases in latitude was likely to associate with the gradients of photoperiod. Climate gradients between populations seemed to contribute to the geographic variation in the height, leaf and phenological traits of B. ermanii.

Leaf trait variation within individuals mediates the relationship between tree species richness and productivity

In forest ecosystems, many ecosystem functions such as tree growth are affected by tree species richness. This biodiversity–productivity relationship (BPR) is mediated by leaf traits, which themselves are known to be influenced by tree species richness; at the same time, as the primary organs of light capture, they are an important factor for tree growth. However, how tree growth is influenced by a tree's ability to phenotypically adjust its leaf traits to the within‐individual light gradient has largely been unexplored. Furthermore, it is not known how such impacts of within‐tree leaf trait variation on individual tree growth sums up to productivity at the community scale. In this study we tested how tree species richness, a tree's mean leaf traits, within‐tree leaf trait variation and the light extinction coefficient within a tree crown influence tree growth. We measured these variables in the temperate forest plantation of the Kreinitz biodiversity experiment. We found that the relationship between tree species richness and tree growth is mediated via the leaf trait variation of the individual trees, which in turn was modified by light availability. In particular, trees in monocultures show a higher within‐individual leaf trait variation, which partly compensates for the lack in among‐species leaf trait variation, and thus affects the BPR. It seems that tree richness operates both through increased acquisitive trait values and within‐individual leaf trait variation, two processes that cancelled out each other and resulted in the absence of a significant effect of tree richness on productivity in our study. In conclusion, to understand the BPR, it is important to study the underlying processes and to know which ones reinforce or oppose each other. In particular, our study highlights the importance of including within‐individual leaf trait variation in ecological research as one important moderator in the BPR.

Crystal structure and interconversion of monomers and domain-swapped dimers of the walnut tree phytocystatin

Biotechnological applications of phytocystatins have garnered significant interest due to their potential applications in crop protection and improve crop resistance to abiotic stress factors. Cof1 and Wal1 are phytocystatins derived from Coffea arabica and Juglans regia, respectively. These plants hold significant economic value due to coffee's global demand and the walnut tree's production of valuable timber and widely consumed walnuts with culinary and nutritional benefits. The study involved the heterologous expression in E. coli Lemo 21(DE3), purification by immobilized metal ion affinity and size exclusion chromatography, and biophysical characterization of both phytocystatins, focusing on isolating and interconverting their monomers and dimers. The crystal structure of the domain-swapped dimer of Wal1 was determined revealing two domain-swapped dimers in the asymmetric unit, an arrangement reminiscent of the human cystatin C structure. Alphafold models of monomers and Alphafold-Multimer models of domain-swapped dimers of Cof1 and Wal1 were analyzed in the context of the crystal structure. The methodology and data presented here contribute to a deeper understanding of the oligomerization mechanisms of phytocystatins and their potential biotechnological applications in agriculture.

Assessment of the Effect of Garcinia kola (Clusiaceae) on the Carbon Sequestration Capacity and Productivity of Cocoa (Theobroma cacao L) in Cocoa-Based Agroforestry Systems

Aims: Ivorian cocoa production reaching 2 million ton annually at the expense of the forest reserve, and an annual deforestation rate around 2.78%. The integration of agroforestry into cocoa plantations appears to be a suitable approach to combating deforestation of the remaining forest reserves and restoring the degraded cocoa landscape. The choice of species is the key to the success of this program. Our objective was to evaluate the interaction between Garcinia kola and cocoa in traditional agroforestry systems. Study Design: Around each Garcinia Kola tree identified in the orchard, two curves lines with radii of 10 and 20 m respectively were delimited in order to assess the interaction of Garcinia Kola on the cocoa tree according to their proximity to Garcinia Kola. Place and Duration of Study: The study was conducted at Gueyo and Buyo in cocoa-based agroforestry systems in western Côte d'Ivoire. from June 2020 to November 2021. Methodology: The influence of Garcinia Kola on cocoa trees was assessed by measuring the biomass and carbon sequestration rate of Garcinia kola and cocoa trees. The productivity of cocoa trees and Garcinia kola was also determined. Results: Our results showed that Garcinia kola trees have an influence on the density and yield of cocoa trees. Cocoa trees close to Garcinia Kola trees within a 10 m radius showed low density and low pod production compared to those within a 20 m radius. Meanwhile, cocoa biomass and carbon sequestration levels were higher in the 10 m radius than the 20 m radius. This study has shown that associated cocoa and Garcinia kola stands make different contributions depending on their proximity. Conclusion: This complementarity in terms of carbon sequestration capacity and productivity between Garcinia Kola and cocoa is an asset that can be exploited for Cocoa agroforestry system to improve the sustainable production system and restore the cocoa landscape.