Determinants of Tobacco Cultivation and the Associated Impacts of Adoption in Hurungwe District, Zimbabwe

Tobacco is an essential cash crop in Zimbabwe and a strategic livelihood option for hundreds of thousands of rural households. However, the crop is linked to negative environmental, economic, and social impacts. The existing studies on tobacco cultivation in Zimbabwe present contradictory findings on the determinants and impacts of adoption, leaving unanswered questions about the crop’s sustainability impact in the country. This article investigates the determinants of smallholder farmers’ decisions to grow tobacco and the associated impacts of adoption. Random and purposive sampling were used to select 273 household surveys, including tobacco and non-tobacco smallholder farmers, and 56 expert interviews to answer the research questions. We employed regression models alongside expert interviews and document analysis to identify the determinants influencing the decision-making process of smallholder farmers in Zimbabwe regarding tobacco cultivation. Additionally, our investigation aimed to elucidate the perceived impacts associated with the adoption of this agricultural practice. The regression analysis indicated that the farmer’s age, education level, farming experience, family size, household income, and perceived high farm profitability are significant drivers of tobacco adoption. We also discovered divergent and convergent perceptions of the critical impacts of tobacco cultivation. The study highlights the need for proactive multi-stakeholder collaboration and sustainable financial arrangements to address the negative impacts of tobacco production. As the primary stakeholder responsible for regulating and promoting agricultural activities, the Zimbabwean government should provide meaningful financial support, increase access to credit, and ensure better market facilities for alternative crops to reduce the over-dependence on tobacco.

Participatory Forest Management and Gender Inclusiveness within the Community Forest Management Groups of Bhutan

Community forest management groups (CFMGs) in Bhutan exhibit participatory forest management practices that recognize the importance of community’s collective participation in the management of natural forest resources. This approach involves the community in the stewardship of designated forest areas and resources to ensure sustainable livelihoods and realization of forest conservation objectives. The increase of CFMGs in the country has been successful. However, research on the extent of gender-inclusive participation in CFMGs is either insufficient or missing vis-à-vis the allocation of decision-making power. Therefore, this study analyzes the factors influencing gender participation in CFMGs and their integration into decision-making processes. Primary data were collected from 12 study sites spanning 4 regions, complemented by secondary data from the Forest Department. Regression models were used to identify factors significantly influencing CFMG member participation in decision-making. The empirical results of this study reveal that gender is a significant factor influencing participation in CFMG decision-making. The study concludes that there is insufficient participation of women members in decision-making processes. Therefore, consideration of gender should be included in the development phase of the CFMG policy in addition to promoting awareness of inequity between gender and the promotion of leadership roles for women in CFMGs.

Analysis of forest structural complexity using airborne LiDAR data and aerial photography in a mixed conifer–broadleaf forest in northern Japan

Determining forest structural complexity,i.e.,a measure of the number of different attributes of a forest and the relative abundance of each attribute,is important for forest management and conservation.In this study,we examined the structural complexity of mixed conifer–broadleaf forests by integrating multiple forest structural attributes derived from airborne Li DAR data and aerial photography.We sampled 76 plots from an unmanaged mixed conifer–broadleaf forest reserve in northern Japan.Plot-level metrics were computed for all plots using both field and remote sensing data to assess their ability to capture the vertical and horizontal variations of forest structure.A multivariate set of forest structural attributes that included three Li DAR metrics(95 th percentile canopy height,canopy density and surface area ratio) and one image metric(proportion of broadleaf cover),was used to classify forest structure into structural complexity classes.Our results revealed significant correlation between field and remote sensing metrics,indicating that these two sets of measurements captured similar patterns of structure in mixed conifer–broadleaf forests.Further,cluster analysis identified six forest structural complexity classes includingtwo low-complexity classes and four high-complexity classes that were distributed in different elevation ranges.In this study,we could reliably analyze the structural complexity of mixed conifer–broadleaf forests using a simple and easy to calculate set of forest structural attributes derived from airborne Li DAR data and high-resolution aerial photography.This study provides a good example of the use of airborne Li DAR data sets for wider purposes in forest ecology as well as in forest management.

Climate Change Impacts, Agroforestry Adaptation and Policy Environment in Sri Lanka

Despite its low emissions of greenhouse gasses (GHGs), Sri Lanka is considered as a vulnerable small island nation under climate change. Agroforestry, which uniquely integrates trees into land use systems, has historically contributed to climate change adaptation in Sri Lanka. Hence, the promotion of agroforestry practices is vitally important to enhance the resiliency of the country to future climate change. This paper reviews the literature and discusses the adverse impacts of climate change on agriculture and forestry, the effects of adapting agroforestry on climate changes, and important policies for promoting agroforestry adaptation in Sri Lanka. The adverse impacts of climate change on agriculture and forestry are identified as follows: endangerment of natural assets;prevalence of pests, diseases and invasive species;agriculture and forest damage;and high levels of food insecurity. The adaptation of agroforestry impacts climate change by increasing the tree cover outside forests, enhancing forest carbon stocks, conserving biodiversity, reducing risks and damage intensity, maintaining health and vitality, and scaling up multiple benefits. Changing regulations and legislation, developing awareness and capacity, planning for climate-smart agroforest landscapes, offering no-regret options and implementing climate change adjustment programs are discussed as important policy measures. It is concluded that agroforestry, along with favourable policy, has an important role in climate change adaptation by enhancing resilience to climate impacts on farming systems.

Management of Village Common Forests in the Chittagong Hill Tracts of Bangladesh: Historical Background and Current Issues in Terms of Sustainability

This study was conducted to investigate the historical management system of village common forests (VCF) in the Chittagong Hill Tracts (CHT) of Bangladesh and observe the current issues related to their sustainability. The study on historical context was based on secondary information to establish the linkages of VCF development and management in the CHT. Field visits to four VCF in the Bandarban Hill Districts were also conducted to cross check the information collected from secondary sources to observe the current status and management pattern of these VCF through semi-structured interviews, group discussion, key-informant interviews and biodiversity assessment. VCF in the CHT undoubtedly play an important role in biodiversity conservation and as well as supporting daily necessities of the community people. We found that VCF still are the source of fuel wood, herbs, roots, bamboo shoots, wild fruits, vines or leaves for cooking or medicinal use necessary to sustain the lives of the indigenous communities in the CHT. Field visits to different VCF show that the VCF are necessarily small in size (57 ha) and around 108 families are dependent on these community managed village forests. A total of 163 plant species from 60 families were also recorded from these VCF including some rare plant and animal species which are not usually found in the reserve forests and the un-classed state forests due to continued deforestation and land degradation. However, population pressure combined with improved marketing facilities, ignorance, over exploitation, personal greed, tenure insecurity, faulty government policies regarding settlement of land and breakdown of the traditional systems exerting pressures on these VCF and the overall condition of these important biodiversity rich areas are degrading or shrinking in size and number gradually. Recognizing the traditional and customary resource rights of the indigenous communities in the CHT, acknowledging resource management system, providing tenure security, encouraging communities through legal and financial incentives in protecting these VCF or any other state owned forest areas solely for the conservation of biodiversity following an intensive management plan, resolving long lasting land related conflicts, and at the same time upholding the spirit of CHT Peace Accord 1997 could be important policy tools for the sustainability of these VCF in the CHT. Lessons learned from this study will be useful in formulating effective policies for community based forest management in Bangladesh and other developing countries.

Geostatistical Approach for Site Suitability Mapping of Degraded Mangrove Forest in the Mahakam Delta, Indonesia

As part of operational guidance of mangrove forest rehabilitation in the Mahakam delta, Indonesia, site suitability mapping for 14 species of mangrove was modelled by combining 4 underlying factors—clay, sand, salinity and tidal inundation. Semivariogram analysis and a geographic information system (GIS) were used to apply a site-suitability model, while kriging interpolation generated surface layers, based on sample point data collection. The tidal inundation map was derived from a tide table and a digital elevation model from topographic maps. The final site-suitability maps were produced using spatial analysis technique, by overlaying all surface layers. We used a Gaussian model to adjust a semivariogram graph in order to help to understand the variation of sample data values, and create a natural surface layer of data distribution over the area of study. By examining the statistical value and the visual inspection of surface layers, we saw that the models were consistent with the expected data behavior;therefore, we assumed that interpolation has been carried out appropriately. Our site-suitability map showed that Avicennia species was the most suitable species and matched with 50% of the study area, followed by Nypa fruticans, which occupied about 42%. These results were actually consistent with the mangrove zoning pattern in the region prior to deforestation and conversion.

Implication for Designing a REDD+ Program in a Frontier of Oil Palm Plantation Development: Evidence in East Kalimantan, Indonesia

To examine the REDD+ (Reducing Emissions from Deforestation and Forest Degradation) program as an alternative to an oil palm plantation in West Kutai district of East Kalimantan, we determined the profitability of land use and REDD+, and the land use preferences and practices of the local people, as well as their participation in and preferences for forestry programs. Our findings indicate the following: 1) the profitability of an oil palm plantation was higher than that from other land uses and the REDD+ program;2) the local preferences for land uses were mostly consistent with the profitability of the land uses, except for oil palm plantation due to non-financial concerns;3) the local people combined each land use in accordance with their various needs;and 4) the local people were interested in a Forest and Land Rehabilitation (RHL) program in nonforestry zones. Considering these evidences, an improved RHL program based on an intensive agroforestry system and a conservation-based REDD+ program based on existing customary conservation forest management by the local people are proposed. Given the high opportunity cost and the low preference for an oil palm plantation, designing the REDD+ program by paying attention to the non-financial benefits for a community is a way forward. To enhance the non-financial benefits, it is important to take into consideration local preferences and livelihood activities in designing the REDD+ program. This study also implies the need for a reconsideration of the position of participation of local people in the safeguards of REDD+.

Prospect of Fuelwood Plantations for Marginal Small Tea Farmers: A Case Study in Matara and Badulla Districts, Sri Lanka

This study demonstrates the importance of conversion of tea farms in marginal land to fuelwood plantation by analyzing the current biophysical, economic and institutional pros and cons of each land uses for marginal small tea plantation holders (MSTH). The study is based on household survey and field investigation conducted in Matara and Badulla Districts of Sri Lanka. Both qualitative and quantitative data on important biophysical, economic and institutional factors was collected from a total of 81 MSTH, 50 from Matara and 31 from Badulla, and fuelwood consuming industries within 20 km of the study area. The result showed that MSTH are facing biophysical and economic problems that are forcing them to leave portion of their tea planation land uncultivated. With ongoing demand increase for fuelwood, presence of tree species already adaptable to the area and favorable property right condition, conversion of the existing marginal land to fuelwood plantation is a viable way to sustainably manage the MSTH farmland. This will also contribute to tackle environmental disasters the area is frequently facing due to abandoning of the marginal tea plantation land.

Identifying the Rates and Drivers of Spatiotemporal Patterns of Land Use and Land Cover Changes in the Hurungwe District, Zimbabwe: A GIS and Remote Sensing Approach

Identifying spatiotemporal patterns of land use and land cover changes (LULCC) and their impacts on the natural environment is essential in policy decisions for effective, sustainable natural resource management solutions. This study employed supervised image classification in Google Earth Engine (GEE) cloud-based platform to assess the land cover land use changes for the past 30 years (1989-2020), as well as predict the land cover states and the risk of future forest loss in the next ten years, using TerrSet 20 software in Hurungwe district, Zimbabwe. The study findings revealed a net forest area and shrub loss of 32% and 10%, while croplands, water bodies, and bare lands have increased by about 171%, 7%, and 119% between 1989 and 2020, respectively. Croplands are the major contributor to the net change in forests, particularly tobacco farming. The predictive model estimated that by 2030 the district would lose approximately 7% of the current forest cover area, most likely converted into croplands, shrubs, and settlements. The results reinforce the importance of bridging the gap between socioeconomic activities and institutional policies to ensure proper natural resource management. Integrating institutional policy and socioeconomic goals is indispensable to ensure sustainable development.

开放式臭氧浓度升高条件下不同敏感型小麦品种的光合特性

利用亚洲首个开放式臭氧浓度升高平台(O3FACE),以臭氧敏感品种烟农19和臭氧耐性品种扬麦16为试材,研究了小麦光合特性对O3浓度升高的响应,并分析了不同敏感型小麦品种响应差异的可能原因。结果表明,O3浓度升高并持续处理75d,小麦旗叶的净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均显著下降,其中扬麦16的降幅(27.9%、37.5%和27.9%)明显小于烟农19(61.1%、68.0%和57.4%);而Ci基本维持恒定。说明O3FACE下小麦旗叶Pn下降是气孔因素和非气孔因素共同作用的结果,其中非气孔因素起决定性作用。叶绿素荧光分析表明,两个品种的PSII最大光化学量子产量(Fv/Fm)、PSII潜在活性(Fv/Fo)、光化学猝灭(qP)和光化学反应速率(Prate)等荧光参数均呈下降趋势,而非光化学猝灭(NPQ)和热耗散速率(Drate)呈上升趋势;可溶性蛋白和核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)则与荧光参数及Pn的变化趋势一致。由此可见,RuBP的羧化限制和PSII光系统损伤可能是O3胁迫下小麦旗叶Pn下降的主要非气孔因素。此外,O3FACE下扬麦16各参数的变幅均小于烟农19,扬麦16较高的蒸腾速率和较小的Rubisco含量降幅可能是其维持光合机构功能的重要原因。

臭氧胁迫使两优培九倒伏风险增加——FACE研究

近地层臭氧(O3)浓度升高使作物生长发育受到抑制进而使产量下降,但O3胁迫条件下作物抗倒性状的变化及其可能原因均不清楚。FACE(Free Air gas Concentration Enrichment)试验在很少扰动的自然农田实施,其特有的空间优势为研究这一问题提供了最好的机会。依托全球唯一的稻田臭氧FACE技术平台,以杂交稻两优培九为供试材料,设置大气背景O3浓度和高O3浓度两个水平首次对这一问题进行了实验研究。结果表明:高O3浓度使水稻抽穗期单茎(去除叶鞘)倒5、倒4和倒3节间的平均倒伏指数分别增加25%、16%和14%,使抽穗后35 d对应节间倒伏指数分别增加13%、12%和2%,除抽穗后35 d倒3节间外均达显著或极显著水平;高浓度O3使水稻抽穗期和抽穗后35 d植株倒5、倒4和倒3节间的抗折力和弯曲力矩均下降,前者降幅明显大于后者;高O3浓度对抽穗期和抽穗后35 d倒5、倒4、倒3和倒2和倒1节间的长度和粗度影响较小,但使各节间单位长度鲜重和干重一致下降,以单位长度干重降幅更大;高O3浓度使结实期倒5、倒4、倒3、倒2和倒1节间可溶性糖和淀粉含有率均下降,抽穗后35 d降幅大于抽穗期。以上数据表明,未来高浓度臭氧环境条件下两优培九结实期的倒伏风险明显增加,这主要与基部节间抗折能力明显削弱有关,而后者可能又与节间充实程度下降有关。

近地层臭氧(O_3)浓度升高对水稻武运粳21抗倒性的影响

依托独特的稻田臭氧FACE(Free air gas concentration enrichment,开放式空气中气体浓度增高)系统平台,以武运粳21为供试水稻品种,设置正常浓度O3(即大气背景浓度)和高浓度O3(实际比大气背景浓度增高25%左右),定量研究地表O3浓度升高对粳稻抗倒能力的影响。结果表明:高浓度O3对水稻抽穗期和抽穗后20 d基部节间的抗折力和弯曲力矩没有显著影响,但使成熟期基部节间的抗折力和弯曲力距有所降低。因此,臭氧胁迫下水稻抽穗期、抽穗后20 d和成熟期基部节间的倒伏指数均无显著变化。进一步研究结果表明,臭氧胁迫下水稻成熟期基部节间单位长度干重和非结构性碳水化合物含量降低引起基部节间充实不良是造成抗折力显著下降的主要原因,而基部节间弯曲力矩下降是稻穗和节间的长度和质量下降共同作用的结果。以上结果表明,未来高浓度臭氧环境条件下粳型水稻的倒伏风险可能不会增加。

近地层臭氧浓度升高对常规稻颖花形成的影响：FACE研究

FACE(free air gas concentration enrichment)研究使用标准的作物管理技术,在完全开放的大田条件下运行,代表了目前人类对未来大气环境的最好模拟。利用独特的大型稻田FACE平台,以典型的常规水稻品种武粳15(粳稻)和扬稻6号(籼稻)为供试材料,研究近地层臭氧(O3)浓度升高(比大气背景臭氧浓度平均增高26%)对常规水稻颖花形成的影响。结果表明:(1)高浓度O3对供试品种全穗以及一、二次枝梗颖化分化数均无显著影响;(2)高浓度O3使供试品种全穗和二次枝梗颖花退化数和退化率均显著增加,颖花退化增多是由于现存一次枝梗上二次枝梗大量退化而引起的二次颖花退化所造成;(3)颖花退化数在颖花分化数中所占比例很低,故高浓度O3对两供试品种全穗和一、二次枝梗颖花现存数以及稻穗构成均无显著影响。结合前报可知,选用常规水稻品种以及增施保花肥可能是未来近地层高浓度O3环境下稻作生产重要的适应措施。

Estimating Individual Tree Diameter and Stem Volume Using Airborne LiDAR in Saga Prefecture, Japan

Advancements in airborne LiDAR analysis technology have made it possible to quantify forest resource volumes based on individual trees, and such technology may soon replace field surveys. Unlike individual tree detection or tree height measurements, diameter at breast height (DBH) is difficult to determine directly from measured data and is instead estimated indirectly using the correlation between crown size and DBH. Indicators that represent crown size include crown area, surface area, length, and length ratio, and were utilized with tree height as explanatory variables in ten combinations to determine a regression formula. DBH and tree height calculated from the regression formula were applied to an equation to calculate stem volumes of individual trees. Airborne LiDAR measurements were taken using ALS50-II and ALS60 (Leica) at a density of 4 points/m2. An evaluation of the relationship between the regression formulae and DBH estimates indicated that a combination of crown area, tree height, and crown ratio for Japanese cedar, and a combination of crown area and tree height for Japanese cypress, yielded the highest coefficients of determination. The average error and RMSE were 6.9% and 2.38 cm respectively for Japanese cedar, while the corresponding values for Japanese cypress were 8.35% and 2.51 cm. Once the relationship was extended to the stem volumes of individual trees, the average error was 14.4% and RMSE was 0.10 m3 for Japanese cedar. The corresponding values for Japanese cypress were 18.9% and 0.10 m3. These results demonstrate the potential use of airborne LiDAR as a substitute for field surveys.

Estimating Crop Coefficient in Intermittent Irrigation Paddy Fields Using Excel Solver

The current study proposes a novel method using Excel Solver to estimate, from limited data, crop coefficient （Kc） in paddy fields under intermittent irrigation （11）. The proposed method was examined in a field experiment conducted at Karang Sari Village, Bekasi, West Java, Indonesia during the first rice season of 2007/2008 （December 2007 to April 2008） in the rainy season. As the control, continuous flooding irrigation （CF） was applied to the conventional rice cultivation fields. Based on the observed water storage, Excel Solver was used to estimate crop evapotranspiration. Estimated crop evapotranspiration was used to compute Kc value, then the average Kc values at each growth stage were compared with that for the CF treatment. The estimation method was evaluated by comparing estimated crop evapotranspiration and the crop evapotranspiration derived by the well established FAO procedure. Excel Solver estimated crop evapotranspiration accurately with R2 values higher than 0.81. Accordingly, more than 81% of the FAO crop evapotranspiration was described by the proposed method. Thus, Kc value could be well determined from those estimated crop evapotranspiration. Under the II treatment, the average Kc values were 0.70, 1.06, 1.24 and 1：22 for the initial, crop development, reproductive and late stages, respectively. These values were lower than those under the CF treatment for initial and crop development stages because of a minimal soil evaporation and intense dryness during these stages. However, average Kc values under the II treatment were higher than those under the CF treatment at the reproductive and late stages, indicating that the II treatment promoted more plant activity particularly for dry biomass production as indicated by a greater number of tillers per hill.

A meta-analysis of responses of wheat yield formation to elevated ozone concentration

The meta-analysis method was applied to quantitatively investigate effects of the elevated ozone concentration ([O3]) on chlorophyll concentration, gas exchange and yield components of wheat. There were 39 effective references through Web of Science (ISI, USA) and Chinese journal full-text database (CNKI, China). The results of meta-analysis indicated that elevated [O3] decreased grain yield, grain weight, grain number per ear, ear number per plant and harvest index by 26%, 18%, 11%, 5% and 11%, respectively, relative to ambient air. The decrease in leaf physiological characters was much greater than that in yield when wheat was expose to elevated [O3], while light-saturated photosynthetic rate (Asat), stomatal conductance (Gs) and chlorophyll content (Chl) decreased by 40%, 31%, and 46%, respectively. The responses to elevated [O3] between spring wheat and winter wheat were similar. Most of the variables showed a linear decrease trend with an increase of [O3]. The most significant decrease for Asat, Gs and Chl was found in grain filling stage. Elevated [CO2] could significantly ameliorated or offset the detrimental effects caused by elevated [O3].

小麦产量形成对大气臭氧浓度升高响应的整合分析

应用整合分析(meta-analysis)方法定量研究了大气臭氧(O3)浓度增加对小麦光合色素、气体交换和产量形成的影响.通过Web of Sciences和中国期刊全文数据库检索,共收集39篇原始论文.结果表明,大气臭氧浓度增加可导致小麦的产量在当前环境浓度的基础上降低26%,籽粒重、穗粒数和穗数分别降低18%,11%和5%,收获指数减少11%.叶片生理对大气臭氧浓度增加的响应比产量敏感得多,如光饱和光合速率、气孔导度和叶绿素含量分别下降40%,31%和46%.春小麦和冬小麦对臭氧的响应相似.大部分指标显示了小麦叶片生理和产量的降低随着臭氧浓度增加而线性增加的趋势.在小麦灌浆期,臭氧浓度增加引起叶片的光合速率、气孔导度和叶绿素含量降低得最大.大气CO2浓度升高可以明显减轻或抵消大气臭氧浓度增加引起的减产效应.

近地层臭氧浓度升高对杂交稻颖花形成的影响

依托全球唯一的稻田开放式空气中臭氧浓度增高系统平台,以汕优63和两优培九为供试材料,设置大气背景臭氧浓度和高臭氧浓度(比大气背景臭氧浓度高50%)两个浓度水平,研究FACE条件下高O3浓度对杂交稻颖花形成的影响.结果表明:高O3浓度使汕优63和两优培九每穗颖花数分别减少28朵和34朵,下降幅度分别为15%和13%.从稻穗构成看,高O3浓度胁迫下杂交稻每穗颖花数减少主要与每穗2次枝梗颖花数明显减少有关,对每穗1次枝梗颖花数的影响较小,因此高O3浓度胁迫下水稻每穗1次枝梗颖花数占全穗的比率增加,每穗2次枝梗颖花数占全穗的比率降低.从颖花形成看,高O3浓度胁迫下杂交稻每穗颖花数下降主要是颖花(特别是2次颖花)的分化受到抑制所致,而颖花的退化数不增反降.上述结果表明,采取相应措施削弱高O3浓度胁迫对颖花分化的抑制作用可能是近地层高O3浓度条件下减少杂交稻产量损失的关键.