Plantation Age Research Articles

Spider species and assemblages in forest plantations of various ages

Spider species and assemblages in forest plantations of various ages

Global mapping of oil palm planting year from 1990 to 2021

Abstract. Oil palm is a controversial crop, primarily because it is associated with negative environmental impacts such as tropical deforestation. Mapping the crop and its characteristics, such as age, is crucial for informing public and policy discussions regarding these impacts. Oil palm has received substantial mapping efforts, but accurate and up-to-date oil palm maps of both extent and age are essential for monitoring impacts and informing concomitant debate. Here, we present a 10 m resolution global map of industrial and smallholder oil palm, developed using Sentinel-1 data for the years 2016–2021 and a deep learning model based on convolutional neural networks. In addition, we used Landsat-5, Landsat-7, and Landsat-8 to estimate the planting year from 1990 to 2021 at a 30 m spatial resolution. The planting year indicates the year of establishment of the current (as of 2021) oil palm plantation by means of either newly planted or replanted oil palm in an existing oil palm plantation. We validated the oil palm extent layer using 18 812 randomly distributed reference points. The accuracy of the planting-year layer was assessed using field data collected from 5831 industrial parcels and 1012 smallholder plantations distributed throughout the global oil palm growing area. We found oil palm plantations covering a total mapped area of 23.98 Mha, and our area estimates are 16.82 ± 0.19 Mha of industrial oil palm and 7.37 ± 0.25 Mha of smallholder oil palm worldwide. The producer's and user's accuracy are 91.0 ± 2.5 % and 91.8 ± 1.2 % for industrial plantations and 71.4 ± 0.7 % and 72.4 ± 1.8 % for smallholders; these values represent an improvement compared to a previous global oil palm dataset, particularly in terms of omission of oil palm. The overall mean error between the estimated planting year and the field data was −0.24 years, and the root-mean-square error was 2.65 years, but the agreement was lower for smallholders. Mapping the extent and planting year of smallholder plantations remains challenging, particularly for wild and sparsely planted oil palm, and future mapping efforts should focus on these specific types of plantations. The average oil palm plantation age was 14.1 years, and the area of oil palm over 20 years old was 6.28 Mha. Given that oil palm plantations are typically replanted after 25 years, our findings indicate that this area will require replanting within the coming decade, starting from 2021. Our dataset provides valuable input for optimal land use planning to meet the growing global demand for vegetable oils. The global oil palm extent layer for the year 2021 and the planting-year layer from 1990 to 2021 can be found at https://doi.org/10.5281/zenodo.13379129 (Descals, 2024a).

Impact of field drying at different initial leaf ages on growth and yield formation of direct seeding rice in Chengdu plain

AbstractTo determine the optimal drying period for direct seeding rice, we conducted experiments using two rice cultivars: hybrid indica (Shuyou 217) and conventional indica (Huang Huazhan). The experiments explored the influence of varying initial leaf development stages on tillering dynamics, leaf area, dry matter production, yield, and yield components in direct seeding rice. The results indicated a significant correlation between the initial leaf development stage and the yield of direct seeding rice. As the initial leaf development stage progressed, the number of effective panicles increased, while key traits affecting panicle yield, such as grain/spikelet? Number per panicle, seed setting rate, and 1000-grain weight, decreased. Additionally, varietal differences in tillering reduction were observed across different leaf development stages. Shuyou 217 exhibited a decrease in heading rate with increasing leaf development stage, whereas Huang Huazhan showed no significant difference. With delayed seeding planting age, both cultivars demonstrated an increasing trend in the leaf area index, initially leading to a rise in effective leaf area proportion, followed by a decline. At the full heading and maturity stages, the dry weight of the stem sheath and panicles per plant decreased as the leaf development stage was delayed. However, the output and transport rates of stem sheath assimilated first increased and then decreased. From a practical perspective, field drying management should be aligned with varietal characteristics to reduce ineffective tillering, ensure sufficient dry matter accumulation during the full heading stage, and optimize post-heading dry matter export and transport. This strategy promotes the coordination between the “source” and “sink” dynamics in rice, ultimately maximizing yield in direct-seeded rice systems.

Differentiated growth of the most widely planted conifer in response to extreme droughts across semi-arid regions in Northern China

Global warming is leading to more frequent and intense drought events, exerting unprecedented pressure on forest growth. Although post-drought recovery in plantation growth has been studied enormously, the variation of planted populations across the whole distribution range of a species is not well understood. In this study, the growth suitability of the most widely planted conifer species in dry lands of northern China, Mongolian Scots pine (Pinus sylvestris var. mongolica), was estimated, based on tree-ring data sampled in 289 plots of afforestation across most of its planting range. According to changes in the hydrothermal condition during the last forty years (1980–2018), the distribution range was divided into three parts: warming, warming-wetting, and non-significant trends (NT) regions. Two severe droughts in 2000 and 2007 were identified using the Standardized Precipitation Evapotranspiration Index (SPEI). Then, the resistance (Rt), recovery (Rc), and resilience (Rs) growth indices were calculated and compared among these three parts. The growth of planted Mongolian Scots pine has overall significantly increased from 1980 to 2018 (p < 0.001). The pine plantations in warming regions were sensitive to annual precipitation, while warming-wetting regions were more influenced by the growing season climate. Pines reverted to pre-drought growth levels within 3 years after the drought event in 2000 but failed in 2007, and populations in the warming region showed significantly lower post-drought recovery. Furthermore, high pre-drought growth levels were linked to low Rs in both drought events (p < 0.001). Post-drought precipitation enhanced the Rc of plantations, compensating for the growth reduction caused by droughts. Soil moisture during the drought events enhanced Rt and Rs. The Rt and Rs indices decreased significantly with the age of plantations (p < 0.05). Overall, our results revealed that pre-drought growth and post-drought precipitation were key factors influencing the resilience of planted Mongolian Scots pine. Besides, the plantations experiencing wetting trends revealed favorable drought resilience and stable radial growth, which indicated promising potential for planted Mongolian Scots pine in those areas. Controlling the age of plantations seems to be crucial for maintaining drought resilience in large-scale plantations and maximizing ecological benefits.

Revealing the optimal strategy for tree plantations on controlling soil erosion in China: A meta-analysis

Tree plantation has increased globally, driven by a desire to supply multiple ecosystem services including soil erosion control. However, how to plant trees can more effectively mitigate soil erosion still lacks systematic investigation. Therefore, we conducted a meta-analysis consisting of 412 paired observations from 80 studies to rigorously compare the effects of tree plantations on soil erosion control across different plantation approaches in China. The results showed that plantation age and ground cover type were the primary factors influencing the efficiency of tree plantations on runoff and sediment reduction. Mature plantations (>20 years) showed more efficiency in runoff (80.9 %) and sediment (97.2 %) reduction than young plantations (<10 years). The benefit of tree plantations with grass cover on runoff reduction was 70 %, while the capacity of plantations without ground cover was not significant. In addition, tree plantations in areas with steep slope, low mean annual precipitation, high soil sand content, and low soil organic carbon had better benefits on soil erosion control. Loess Plateau and Karst areas suffer the most severe water erosion in China, with distinct environmental conditions. This paper further revealed the targeted plantation strategy for these two regions: tree plantations in Karst areas should focus on the lithophyticity and drought tolerance of tree species, in the Loess Plateau should consider the trade-off between water consumption and soil erosion control.

Evaluating Carbon Sequestration and Biodiversity in Cocoa Agroforestry Systems: A Case Study from the Man Region, Côte d'Ivoire

Aims: Cocoa-based agroforestry systems in the Man region of Côte d'Ivoire are essential for balancing agricultural productivity and environmental preservation. This study assessed these systems regarding plant biodiversity conservation and carbon sequestration. Study Design and Methodology: The research was carried out in 21 cocoa plantations, aged between 14 and 32 years, across 60 botanical inventory plots, each measuring 10 by 20 meters. Tree heights and diameters were recorded to estimate Above Ground Biomass (AGB) using the equation AGB = 0.0673 × (ρD²H)0.976, where D is diameter, H is height, and ρ is specific density. Below Ground Biomass (BGB) was calculated as BGB=AGB×0.24, while total biomass (BT) was obtained as BT=AGB+BGB. Carbon stock (C) was derived using C=BT×0.5. Statistical analysis was applied to compare mean carbon stocks across different plantation ages. Results: The plantations, ranging from 8 to 32 years old, showed a diversity of companion species. The diversity of companion species in cocoa agrosystems varies from 4 in 8–10-year-old plantations to 12 in 14- and 15-year-old plantations. Carbon sequestration was age-dependent: younger plantations (5-10 years) sequestered 19.77 ± 2.32 tonnes per hectare, plantations aged 10-15 years stored 133.70 ± 253.50 tonnes, while middle-aged plots (15-20 years) reached 398.76 ± 861.51 tonnes. The oldest plantations (30-35 years) sequestered 137.94 ± 280.31 tonnes. Effective plantation management increased both carbon sequestration and biodiversity. Conclusion: The study highlights the importance of species diversity and continuous management in cocoa-based agroforestry systems. Optimized agroecological practices enhance biodiversity conservation and carbon sequestration, providing practical insights for stakeholders involved in agricultural sustainability, biodiversity conservation, and climate change mitigation. Cocoa agroforestry aligns economic and environmental objectives, offering a sustainable agricultural model.

Fruit quality of 'Stanley' plums based on soil composition across diverse agro-ecological zones of Morocco

The national production of plums, especially prunes, is strongly increasing, attracting attention in the local market. This study aims to assess the impact of soil chemical composition on the nutritional and physicochemical quality of plums of the variety ''STANLEY'' (Prunus Domestica L.) across diverse agro-ecological zones of Morocco. Through a preliminary survey of 21 growers in three distinct regions: Sais, Atlas and Oriental. Supplemented by sampling at eight locations in eastern and western Morocco, three categories of parameters were considered in this study: (1) parameters related to cultivation conditions, including climate, geographical structuring, plot size and planting age; (2) those providing information on physico-chemical properties, nutritional value and sugar content; (3) parameters related to soil quality. The surveyed farmers are proprietors of cultivated plots ranging from 6 to 70 hectares, with an average yield of 12T/ h. Notably, 28% of producers with recently established plantations (less than 10 years) have achieved yields exceeding 15T/h, indicating the fertility of trees at this stage of maturity. The findings affirm that soil fertility and soil amendment are the major factors contributing to high-quality fruit (large caliber, high Brix rate, intact product…). Additionally, this study highlights the significance of climate and irrigation in achieving the desired quality of plums.

Effects of Vegetable Planting Ages on Community Structure of Ammonia-oxidizing Archaea and Ammonia-oxidizing Bacteria in Greenhouse Vegetable Fields

The ammonia oxidation process driven by microorganisms is a dominant source for nitrous oxide （N2O） emissions. Here, we examined the influence of greenhouse vegetable planting ages on soil ammonia-oxidizing archaea （AOA） and ammonia-oxidizing bacteria （AOB）, which is of great significance for assessing the soil quality status and greenhouse gas transformations. A field study was conducted at different times （1, 5, 10, and 20 a） in greenhouse vegetable soils of Gaoyi, Hebei Province. Chemical analysis and Illumina NovaSeq high-throughput sequencing were used to analyze the soil physicochemical properties and community structures and diversity of AOA and AOB. The variation in AOA and AOB communities and the driving factors in greenhouse soils at different ages were also investigated. The results showed that the contents of total nitrogen, organic matter, alkali-hydrolyzable nitrogen, available phosphorus, and available potassium first increased and then decreased with the prolongation of growth. The contents of nitrate nitrogen, ammonium nitrogen, and electrical conductivity first decreased and then increased with the prolongation of growth. The pH value of soils decreased with the prolongation of growth. The abundance and diversity index of AOA and AOB first decreased and then increased with the prolongation of growth. Nitrososphaeria, unclassified Thaumarchaeota, and Candidatus Nitrosocaldus were the dominant species of AOA, while Betaproteobacteria and Nitrosospira were the dominant species of AOB. The composition of the soil AOA community varied greatly compared to that of AOB with the prolongation of growth. Correlation analysis showed that the changes in soil nutrient factors had a significant correlation with AOA and AOB communities. Redundancy analysis indicated that ammonium nitrogen, alkali-hydrolyzable nitrogen, and nitrate nitrogen were key factors of AOA communities, while electrical conductivity, available potassium, and nitrate nitrogen were key factors for AOB. In summary, long-term planting of greenhouse vegetables significantly affected the abundance and composition of soil AOA and AOB communities. Our results provide a theoretical basis for further studies on the greenhouse gas transformation and microbial mechanisms of the nitrogen cycle in greenhouse soils.

Analysis of Mycorrhization Trends and Undesired Fungi Species in Three- and Six-Year-Old Tuber aestivum Plantations in Hungary.

Tuber aestivum is a key truffle species with significant ecological and economic value. Despite its importance, plantation success can be influenced by soil pH, host plants, and undesired fungi. This study examines how soil pH and host plants influence mycorrhization trends in T. aestivum plantations across six plant species in eight Hungarian settlements, using root sampling and DNA analysis to assess plantations at three and six years of age. Tuber aestivum achieved over 30% mycorrhization, with Carpinus betulus showing the highest levels. DNA analysis identified eight undesired mycorrhizal fungi, with Suillus spp. (42.9%) and Scleroderma spp. (31.4%) being the most prevalent. The study found that T. aestivum preferred a soil pH of around 7.6, while undesired fungi thrived in slightly acidic conditions. Additionally, soil pH significantly and positively influenced T. aestivum mycorrhization; however, factors such as plantation age also contributed to mycorrhization trends. While mycorrhization by undesired fungi decreased with higher soil pH, it increased as plantations matured from three to six years. These findings highlight the need for the effective management of soil pH and the control of undesired fungi to optimize T. aestivum mycorrhization, emphasizing the importance of targeted strategies and further research for sustainable truffle cultivation.

Remotely Piloted Aircraft for Evaluating the Impact of Frost in Coffee Plants: Interactions between Plant Age and Topography

An accurate assessment of frost damage in coffee plantations can help develop effective agronomic practices to cope with extreme weather events. Remotely piloted aircrafts (RPA) have emerged as promising tools to evaluate the impacts caused by frost on coffee production. The objective was to evaluate the impact of frost on coffee plants, using vegetation indices, in plantations of different ages and areas of climatic risks. We evaluated two coffee plantations located in Brazil, aged one and two years on the date of frost occurrence. Multispectral images were collected by a remotely piloted aircraft, three days after the occurrence of frost in July 2021. The relationship between frost damage and these vegetation indices was estimated by Pearson’s correlation using simple and multiple linear regression. The results showed that variations in frost damage were observed based on planting age and topography conditions. The use of PRA was efficient in evaluating frost damage in both young and adult plants, indicating its potential and application in different situations. The vegetation index MSR and MCARI2 indices were effective in assessing damage in one-year-old coffee plantations, whereas the SAVI, MCARI1, and MCARI2 indices were more suitable for visualizing frost damage in two-year-old coffee plantations.

Carbon accumulation in the soil and biomass of macauba palm commercial plantations

Commercial cultivation of the Macauba palm is growing due to its agro-energy potential. This study quantified carbon stock in two macauba plantations (4.8 and 9.0 years old), considering carbon stored in soil and biomass. We assessed total organic carbon (TOC) stocks in labile (EOC and LF-C) and non-labile (NL-C) soil fractions, comparing these with a forest regenerating for over 30 years. Soil samples were collected within the palm plantation (rows and inter-rows) and the forest area at five depths (0–10, 10–20, 20–40, 40–60, and 60–100 cm). The impact of plantation age and sampling position on TOC stocks and organic matter fractions across different soil layers (0–100 cm) was assessed. The Carbon Management Index (CMI) was calculated to evaluate carbon recovery. Plantation age and sampling position influenced soil TOC stocks across all depths up to 1 m. Higher TOC and NL-C soil stocks were observed in the older plantation (9.0 years) and inter-row. EOC and LF-C fractions varied by soil layer. The inter-row region of the 9.0-year-old plantation exhibited higher carbon recovery based on the CMI. Over 4.2 years of palm cultivation (between 4.8 and 9.0 years), carbon accumulation in biomass and soil reached 75.36 Mg C ha−1. These findings underscore the potential of commercial macauba plantations to enhance soil carbon stocks rapidly, particularly in inter-row areas. Plantations younger than a decade surpassed the soil carbon stock of a forest regenerating for over 30 years, highlighting significant environmental benefits of macauba cultivation, including soil and biomass carbon sequestration.

Carbon Sequestration Characteristics of Typical Sand-Fixing Plantations in the Shiyang River Basin of Northwest China

A predominant management practice to reduce wind erosion in the arid deserts of northwest China is the planting of shrubs. However, the carbon sequestration capacity of these sand-fixing plantations has not received much attention. In this study, the carbon sequestration capacity of six typical sand-fixing plantations (Haloxylon ammodendron (C. A. Mey.) Bunge, Caragana korshinskii Kom., Tamarix ramosissima Ledeb., Calligonum mongolicum Turcz., Artemisia desertorum Spreng. and Hedysarum scoparium Fisch. &amp; C. A. Mey.) in the Shiyang River Basin were compared and analyzed. We evaluated how carbon sequestration may vary among different species, and examined if plantation age or management style (such as the additional construction of sand barriers, enclosure) positively or negatively influenced the carbon storage potential of these plantation ecosystems. Our results showed that all six plantations could store carbon, but plant species is the controlling factor driving carbon stock accumulation in plantations. The actual organic carbon stored beneath 25-year-old T. ramosissima, H. ammodendron, C. korshinskii, H. scoparium, C. mongolicum and A. desertorum plantations was 45.80, 31.80, 20.57, 20.2, 8.24 and1.76 Mg ha−1, respectively. Plantations using a clay–sand barrier had 1.3 times the carbon sequestration capacity of plantations that only used wheat straw and sand barriers. Similarly, enclosed plantations had 1.4 times the carbon storage capacity of unenclosed plantations. Plantation age greatly impacts carbon sequestration capacity. A 25-year-old H. ammodendron plantation has a carbon sequestration capacity three times greater than that of 3-year plantation. We conclude that while afforesting arid areas, H. ammodendron and T. ramosissima should be prioritized, and priority also should be given to using clay–sand barrier and enclosure.

Sampling Method to Estimate Fresh Fruit Bunch Production in Oil Palm Using Geostatistical Techniques

In oil palm cultivation, harvesting is a task that demands the most attention, resources, and accuracy. The logistics of harvesting activities, from bunch cutting through delivery to processing, are organized as a function of yield per hectare, and this planning depends on production samples collected from plantations to estimate the number of fresh fruit bunches that will be harvested per crop management unit. Conventionally, production is estimated through sampling grids, most commonly every five rows and every five palms (5 × 5), 7 × 7, or 10 × 10. Sampling density, however, does not typically result from a statistically rigorous method. Therefore, the objective of the present study was to define, using geostatistics, adequate sampling grids for estimating production. Specifically, seven lots in different Colombian oil palm-growing regions with planting ages between 5 and 9 years were analyzed, and the number of reproductive structures of all oil palms was recorded. From the semivariogram of each lot, different models were proposed, fitted, and cross-validated. For each sampling grid, all possible samples were simulated in the respective lots to determine the degree of accuracy in estimating oil palm production. The optimal sampling grids differed between lots, ranging from 3 × 3 to 15 × 15.

A potential cause for extensive dieback of Acacia mearnsii plantation in highland districts of Awi zone, northwestern Ethiopia

Although Acacia mearnsii De Wild has rapidly expanded for economic and ecological purposes in the highland districts of the Awi zone, northwestern Ethiopia, recent plantations have suffered from severe defoliation, dieback, and stunted growth. We conducted this study in four districts that hold potential for A. mearnsii plantations. The study examined the identification of the causal agent, its occurrence, and local community perceptions of the plantation's significant dieback. Most respondents (75.8 %) indicated that the substantial dieback began in the rainy season of 2020 and spread rapidly. They also noted that close spacing of plantings and limited silvicultural measures exacerbated the damage. We discovered in this study that the wattle rust disease caused by the Uromycladium acacia fungus was the root cause of significant dieback for A. mearnsii plantations. The incidence and severity of this wattle rust varied significantly (p = 0.001) between districts, seasons, and plantation age groups. In Fegita-Lekuma district, the maximum disease severity was over 72 % in plantations up to two years after planting during the rainy season. The progression of the wattle rust disease caused by U. acacia has led to the loss of A. mearnsii plantations in the Awi zone, resulting in a severe economic and environmental crisis. Consequently, we should apply fungicides to seedlings at nursery sites in the short term. Eventually, however, the focus should shift towards prioritizing disease-resistant species and implementing proper forest management practices. This should be achieved through scientific initiatives that engage key stakeholders in areas where this tree species could potentially grow.

Long-term evolution of soil quality in citrus orchard terrace system: A whole life cycle perspective

Terracing is widely recognized as an effective strategy for mitigating soil erosion and preserving soil quality. This study aimed to evaluate the variations in soil aggregate C, N, and P composition, as well as the soil quality index (SQI), in subtropical citrus orchards of different plantation ages (PA) and across various terrace positions (TP). Surface soil samples (0–20 cm) were collected from four TP categories: terrace wall (TW), slub ditch (SD), under grove (UG), and between grove (BG), across varying PA (5, 15, 25, 35, and 45 years). The results showed the C, N, and P concentrations in most soil aggregates, along with the SQI of the slub ditch and under grove, increased significantly with plantation age. Compared to the 5-year-old plantations, the SQI of the slub ditch and under grove increased by 84 % and 66 % at 45 years, respectively. The aggregate stability and SQI of BG generally trended upwards but declined at 25 and 35 years. By 45 years, the SQI of the terrace wall was significantly lower than that of other positions, being 58 %, 61 %, and 39 % lower compared to the slub ditch, under grove, and between grove, respectively. Additionally, the C/P and N/P ratios of the terrace wall were higher than those of other positions, indicating phosphorus limitation in TW. Path analysis revealed plantation ages had greater effects on SQI. Aggregate stability and soil properties showed significant positive impacts on SQI. Overall, as plantation age increased, the differences in SQI among the slub ditch, under grove, and between grove decreased, while the terrace wall exhibited the weakest erosion resistance. Therefore, efforts should be made to restore the ecological function of the terrace wall, such as by colonizing it with moss. Additionally, reasonable tillage plans, including appropriate fertilization, should be formulated to enhance orchard soil quality.

Characteristics of different aged plantations of Ormosia hosiei with regards to soil microbial biomass and enzymatic activities

Characteristics of different aged plantations of Ormosia hosiei with regards to soil microbial biomass and enzymatic activities

Response of Soil Fungal Community to Reforestation on Shifting Sand Dune in the Horqin Sandy Land, Northeast China.

Reforestation of native shrub on shifting sand dunes has been widely used for desertification control in semi-arid grassland in Northeast China. Previous studies have confirmed that plantation establishment facilitates fixing sand dunes, restoring vegetation, and improving soil properties, but very few have focused on the response of the soil fungal community. In this study, a chronosequence of Caragana microphylla (CM) shrub sand-fixation plantations (8-, 19-, and 33-year-old), non-vegetated shifting sand dunes (0 years), and adjacent natural CM forests (NCFs; 50-year-old) in the Horqin sandy land were selected as experimental sites. Soil properties including enzymatic activities were determined, and the composition and structure of the soil fungal community were investigated using the Illumina MiSeq sequencing technique based on the internal transcribed spacer (ITS) rDNA. This study aimed to (1) describe the response of the soil fungal community to revegetation onto a moving sand dune by planting a native shrub plantation; (2) determine the main soil factors driving the succession of the fungal community; and (3) discuss whether the soil fungal community can be restored to its original state by reforestation. The reforestation of CM significantly ameliorated soil properties, increased soil fungal diversity, and altered the composition and structure of the soil fungal community. Ascomycota, Basidiomycota, and Zoopagomycota were the dominant phyla in all sites. Ascomycota did not respond to plantation development, whereas the other two dominant phyla linearly increased or decreased with the plantation age. The relative abundance of dominant genera varied with sites and showed a waning and waxing characteristic. The composition and structure of the soil fungal community in the 33-year CM plantation were very close to that of the NCF, indicating the restorability of the soil fungal community. The succession of the soil fungal community was directly driven by soil properties, of which soil moisture, organic matter, total N, urease, and protease were the main affecting factors.

Estimation of changes in carbon sequestration and its economic value with various stand density and rotation age of Pinus massoniana plantations in China

Plantations actively participate in the global carbon cycle and play a significant role in mitigating global climate change. However, the influence of forest management strategies, especially planting density management, on the biomass carbon storage and production value of plantations for ensuring carbon sink benefits is still unclear. In this study, we estimated the carbon sequestration and economic value of Pinus massoniana plantations with various stand densities and rotation ages using a growth model method. The results revealed that with increasing stand age, low-density plantations at 2000 trees·ha−1 (358.80 m3·ha−1), as well as high-density plantations at 4500 trees·ha−1 (359.10 m3·ha−1), exhibited nearly identical standing volumes, which indicated that reduced inter-tree competition intensity favors the growth of larger trees during later stages of development. Furthermore, an increase in planting density led to a decrease in the average carbon sequestration rate, carbon sink, and number of trees during the rapid growth period, indicating that broader spacing between trees is favorable for biomass carbon accumulation. Further, extending the rotation period from 15 to 20 years or 25 years and reducing the optimal planting density from 3000 to 2000 trees·ha−1 increased the overall benefits of combined timber and carbon sink income by 2.14 and 3.13 times, respectively. The results highlighted that optimizing the planting density positively impacts the timber productivity and carbon sink storage of Pinus massoniana plantations and boosts the expected profits of forest managers. Thus, future afforestation initiatives must consider stand age and planting density management to shift from a scale-speed pattern to a quality-benefit design.

Genetic Structure of Ganoderma boninense Populations Associated with Oil Palm at Neighboring Fields with Different Planting Ages in Malaysia.

Ganoderma boninense is a basidiomycete pathogen of African oil palm (Elaeis guineensis) and the causal agent of basal stem rot (BSR) disease, which is the most destructive fungal disease of oil palm in Southeast Asia. The disease is fatal for infected palms and can result in 50 to 80% losses in oil yields because of a reduction in productive life span and a yield decline of infected oil palms. In this study, G. boninense isolates collected from different locations and planting blocks with different palm ages were molecularly characterized using microsatellite genotyping. Results showed high pathogen genetic diversity (He = 0.67 to 0.74) among planting blocks and between oil palm estates. Two nearby planting blocks with similar planting ages (i.e., 1999 and 2001) had a similar percentage of BSR incidence (>20%) but showed distinct Ganoderma genetic structure as detected using STRUCTURE. Similar results were obtained from another trial site where planting blocks differing in planting age but located only less than 1 km apart showed a diverse genetic background. The pathogen genetic admixture of the oldest planting (>30% BSR incidence) differed significantly from the younger planting (1.8 to 2.8% BSR incidence, breeding trial block), suggesting that the host-pathogen genotype interaction may impact the Ganoderma genetic variation over time. The genetic structure of G. boninense, as revealed in this study, implies positive selection resulting from the pathogen genetic variation, host-pathogen interaction, and possible introductions of novel genetic variants (through spores) from adjacent plantings. These findings offer new insights into the genetic changes of G. boninense over time. The information is essential to design disease management strategies and breeding for BSR resistance in oil palm.

Assessing the Financial Risks in Guava Cultivation in the Pabna District of Bangladesh

Guava cultivation in Bangladesh is vital for being the sources of cancer prevention agents, vitamin, beta-carotene, zinc, copper, manganese, etc, which are fundamental for human body. The major objective of the study was to measure the financial risks in guava cultivation in Pabna district of Bangladesh. In order to measure the financial risks in guava production, the research studied the nature of NPV of guava orchards in the Pabna district of Bangladesh. For this purpose, the study estimated the average total net cash flows of each year by considering all the possible costs and benefits associated guava production for the selected orchards to determine their NPVs. A set of cross-sectional data on the selected variables has been used for the analyzing purpose of the research. A multi-stage sampling technique consists of purposive, cluster and simple random sampling has been applied for the selection of 100 guava orchards, from two upazilas of the district. Subsequently, a structured questionnaire composed of both open and closed-ended questions has been used for collecting data from the sample guava producers with the help of face-to-face interview method. The study employed simulation analysis to assess the financial risks in guava production in the selected area. The results revealed that the values of total net return in the first five years are negative, it become positive in the sixth year and thereafter. The value of total net return in the seventh year is BDT 63433 per bigha (1 bigha equals about 0.1335 hectare) and it continues to be stable up to 25 years of age of the guava plantation. The 1000 runs of simulation of NPV of guava orchard given that the NPV ranges from -BDT 18302.3 per bigha to BDT 184866 per bigha with a mean value of BDT 80649.51 per bigha. The distribution of the NPV which evident that the probability of a higher value or negative value of NPV is very low. The moderate value of NPV is the most likely outcome. The results of the simulation analysis inferred that the investment in the guava orchard is neither highly profitable nor loss-making which means that investment in this project bears a very low financial risk.