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Frontiers in Forests and Global Change
Number of Followers: 3  Open Access journalISSN (Online) 2624-893X Published by Frontiers Media  [96 journals]
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- Exploration of large-scale vegetation transition in wet ecosystems: a
comparison of conifer seedling abundance across burned vs. unburned
forest-peatland ecotones in Western Patagonia
Authors: Kyla Zaret, Andrés Holz
Abstract: Altered fire regimes, combined with a warmer and drier climate, have been eroding the resilience of temperate rainforests and peatlands worldwide and leading to alternative post-fire vegetation communities. Chronic anthropogenic burning of temperate rainforests at the forest-peatland ecotone in western Patagonia appears to have shifted vegetation communities in poorly-drained sites from forests dominated by the threatened conifer, Pilgerodendron uviferum, to peat-accumulating wetlands covered by Sphagnum mosses. We collected and modeled post-reburn field data using ordinations and hierarchical Bayesian regressions to examine mechanisms through which P. uviferum forests may recover following fire or become locked into alternative development pathways by comparing biophysical factors of a reburned ecotone to those of an unburned (control) ecotone. We found that, (1) the significantly higher densities of P. uviferum trees and seedlings in the forested patches at both the reburned and control sites were associated with significantly lower seasonal water tables, lower cover of Sphagnum mosses and higher cover of other mosses (i.e., not in the Sphagnum or Dicranaloma genera); (2) despite abrupt boundaries in vegetation at both sites, successive fires homogenized the environment at the reburned site; and (3) the distinct life forms and individual species that characterized the understory plant communities across the ecotones affected seedling abundance by shaping microtopography and the substrates available for establishment. Together, our results suggest that fire can push edaphically wet P. uviferum-dominated sites towards a non-forested state by reducing the diversity of microsite structure and composition, thereby placing P. uviferum seedlings in direct competition with Sphagnum mosses and potentially limiting the availability of microsites that are protected from both seasonal inundation and seasonal drought. If wildfires continue under increasingly warmer and drier conditions, the forest-peatland ecotone of western Patagonia may be susceptible to large-scale transformation towards a non-forested state.
PubDate: 2024-08-07T00:00:00Z
- Physiological and biochemical changes of Picea abies (L.) during acute
drought stress and their correlation with susceptibility to Ips
typographus (L.) and I. duplicatus (Sahlberg)
Authors: Sara Basile, Barbora Stříbrská, Alina Kalyniukova, Jaromír Hradecký, Jiří Synek, Jonathan Gershenzon, Anna Jirošová
Abstract: IntroductionIn recent years, Norway spruce (Picea abies L.) forests in Central Europe have faced escalating threats from bark beetles, primarily Ips typographus (L.), and other species, such as I. duplicatus (Sahlberg). Outbreaks are partially attributed to weakened tree defense resulting from drought periods induced by climate change. This study examines Norway spruce’s physiological and metabolic reactions to acute drought stress during the growing season and evaluates its susceptibility to I. typographus and I. duplicatus.MethodologyIn order to induce drought stress, mature Norway spruces had their roots covered with a roof in April 2021, depriving them of water. Control trees were left with free access to natural rainwater. Over 5 months of the growing season, soil water potential, bark temperature, tree trunk circumference, and sap flow were monitored. Roofed trees and controls were sampled in July, August, and September and analyzed for non-structural carbohydrates and the two classes of defensive compounds, phenolics and terpenes. Furthermore, two different bioassays in tubes and boxes were performed using adult I. typographus and I. duplicatus beetles to assess host choice and acceptance.ResultsRoofed trees exhibited signs of stress as early as July, resulting in decreased tree trunk and a consequent increase in non-structural carbohydrate content. Defensive metabolites remained largely unaffected except for an increase in diterpenes in September. In bioassays, I. typographus preferred boring into the bark of roofed trees in August in tubes and in September in boxes. This increased tree acceptance correlated with increased levels of soluble carbohydrates in the phloem. I. typographus and I. duplicatus beetles showed higher mobility in boxes in August and September on roofed trees but not in July, even though bark surface temperatures were elevated in roof-covered trees during all three bioassay periods.ConclusionThe study revealed rapid physiological responses of trees to acute drought stress, although not many changes were observed in defense traits. Despite the absence of natural bark beetle attacks, drought trees were more accepted by I. typographus than naturally watered trees. This response may indicate the beetles’ preference for trees with phloem of higher nutritional quality induced by the acute drought stress conditions.
PubDate: 2024-08-07T00:00:00Z
- Cost reduction for upscaling voluntary sustainability standards: the case
of independent oil palm smallholders in Central Kalimantan, Indonesia
Authors: Silvia Irawan, Katryn Pasaribu, Jonah Busch, Arie Dwiyastuti, Heni Martanila, Dyah Retnani, Dwiki Mirjan Fajri, Venticia Hukom
Abstract: Upscaling Voluntary Sustainability Standards (VSS) can generate ecological and social benefits at a scale that is meaningful to address pressing environmental issues such as climate change and biodiversity losses. Lack of resources and risks of implementation gaps may, however, hinder the success of upscaling VSS. This paper aims to fill the gap in the literature regarding options to reduce certification costs to upscale VSS amid the limited financial resources available for certification. The paper presents the result of action research involving 3,507 independent oil palm farmers who are members of six farmer groups in two districts in Central Kalimantan to achieve Roundtable on Sustainable Palm Oil (RSPO) certification. The research found that achieving economies of scale by increasing the total number of certified farmers can reduce the certification costs per farmer. By establishing a district-level entity, the costs related to audits, RSPO membership fees, and the establishment of farmer groups, such as developing standard operating procedures (SOPs), can be lowered. Implementation gaps were not found with the increase of farmers joining the project based on the training frequency and the external audit findings reports on farmers' compliance with RSPO principles and criteria. The findings of this study provide a basis for promoting the upscaling of VSS, including through the RSPO jurisdictional approach.
PubDate: 2024-08-06T00:00:00Z
- Abundance, diversity and composition of understory plants along the
altitudinal gradient and dominant overstory composition types in the
temperate Himalayan region
Authors: Saveena Sangry, Praveen Kumar, D.R. Bhardwaj, K.S. Dogra, Poonam
Abstract: IntroductionThe Indian Himalayan forests are remarkable landforms experiencing tremendous climatic variation, constituting complex and diversified ecosystems with prominent vegetation zones. Despite their global significance and substantial research efforts focused on plant diversity in the temperate Himalayan region, only a few studies have explicitly assessed the distribution patterns of understory vegetation in relation to forest compositional types along altitudinal gradients.MethodsTo cover a wide range of altitudes and diverse overstory compositions, stands were sampled across four altitudinal ranges from 1500 to 3500 meters above mean sea level with increments of 500 meters in elevation steps. The overstory compositions were classified on the basis of dominant tree species in each stand on the similar sites. Vegetation in the shrub and ground layers was surveyed by visually estimating the percentage coverage within circular plots.ResultsA total of 99 understory species including 37 species each in the shrub layer, 62 species in the herb layer vegetation were recorded. The abundance, species diversity and composition of understory vegetation differed significantly along the altitudinal gradient and dominant overstory composition types. Moreover, distinct understory vegetation communities were observed at lower elevations compared to higher elevations, with middle elevations exhibiting intermediate vegetation characteristics. The study also highlighted the importance of dominant overstory composition types in shaping the pattern of understory vegetation abundance, species diversity and composition in the temperate Himalayan region. The higher resource conditions associated with broadleaved stands supported higher understory species abundance at lower elevations, while the heterogeneous conditions induced by the mixedwood stands promoted higher understory species diversity.ConclusionThe hump shaped pattern along the altitudinal gradient appeared to be the most dominant pattern of plant abundance and species diversity and call for more conservation concern towards the middle elevation zones in the temperate Himalayan region. Furthermore, the management interventions should aim at maintaining diverse range of overstory composition types for conserving biodiversity and their ecological functions in the temperate Himalayan region.
PubDate: 2024-08-06T00:00:00Z
- Fire behavior simulation of Xintian forest fire in 2022 using WRF-fire
model
Authors: Hongmei Hu, Xiangwen Deng, Gui Zhang, Lanbo Feng, Jun Long, Ziming Li, Yu Zhu, Yiying Wang
Abstract: IntroductionThe behavior of forest fire is a complex phenomenon, and accurate simulation of forest fire is conducive to emergency response management after ignition. In order to further understand the characteristics of forest fire spread and the applicability of WRF-Fire in China, which is a coupled fire-atmospheric wildfire model, this study simulated a high-intensity forest fire event that occurred on October 17, 2022 in Xintian County, southern Hunan Province.MethodsBased on the fire-atmosphere coupled WRF-Fire model, we used high-resolution geographic information, meteorological observation and fuel classification data to analyze the forest fire behavior. At the same time, the simulation results are compared with the fire burned area observed by satellite remote sensing forest fire monitoring data.ResultsThe study found that, the simulated wind speed, direction and temperature trends are similar to the observation results, but the simulated wind speed is overestimated, the dominant wind direction is N, and the temperature is slightly underestimated. The simulated wind field is close to the actual wind field, and the simulation results can show the spatial and temporal variation characteristics of the local wind field under complex terrain while obtaining the high-resolution wind field. The simulated fire burned area is generally overestimated, spreading to the north and southwest compared with the observed fires, but it can also capture the overall shape and spread trend of the fire well.DiscussionThe results show that the model can accurately reproduce the real spread of fire, and it is more helpful to forest fire management.
PubDate: 2024-08-06T00:00:00Z
- Global assessment of production benefits and risk reduction in
Authors: Sneha Dobhal, Raj Kumar, Ajay Kumar Bhardwaj, Sangram Bhanudas Chavan, A. R. Uthappa, Manish Kumar, Awtar Singh, Dinesh Jinger, Pravin Rawat, Anil Handa, Naleeni Ramawat
Abstract: Climate change and extreme weather events are threatening agricultural production worldwide. The anticipated increase in atmospheric temperature may reduce the potential yield of cultivated crops. Agroforestry is regarded as a climate-resilient system that is profitable, sustainable, and adaptable, and has strong potential to sequester atmospheric carbon. Agroforestry practices enhance agroecosystems’ resilience against adverse weather conditions via moderating extreme temperature fluctuations, provisioning buffers during heavy rainfall events, mitigating drought periods, and safeguarding land resources from cyclones and tsunamis-type events. Therefore, it was essential to comprehensively analyze and discuss the role of agroforestry in providing resilience during extreme weather situations. We hypothesized that integrating trees in to the agro-ecosystems could increase the resilience of crops against extreme weather events. The available literature showed that the over-story tree shade moderates the severe temperature (2–4°C) effects on understory crops, particularly in the wheat and coffee-based agroforestry as well as in the forage and livestock-based silvipasture systems. Studies have shown that intense rainstorms can harm agricultural production (40–70%) and cause waterlogging. The farmlands with agroforestry have been reported to be more resilient to heavy rainfall because of the decrease in runoff (20–50%) and increase in soil water infiltration. Studies have also suggested that drought-induced low rainfall damages many crops, but integrating trees can improve microclimate and maintain crop yield by providing shade, windshield, and prolonged soil moisture retention. The meta-analysis revealed that tree shelterbelts could mitigate the effects of high water and wind speeds associated with cyclones and tsunamis by creating a vegetation bio-shield along the coastlines. In general, existing literature indicates that implementing and designing agroforestry practices increases resilience of agronomic crops to extreme weather conditions increasing crop yield by 5–15%. Moreover, despite its widely recognized advantages in terms of resilience to extreme weather, the systematic documentation of agroforestry advantages is currently insufficient on a global scale. Consequently, we provide a synthesis of the existing data and its analysis to draw reasonable conclusions that can aid in the development of suitable strategies to achieve the worldwide goal of adapting to and mitigating the adverse impacts of climate change.
PubDate: 2024-07-31T00:00:00Z
- Maximizing opportunities for co-implementing fuel break networks and
restoration projects
Authors: Bruno A. Aparício, Alan A. Ager, Michelle A. Day
Abstract: Increasing impacts from wildfires are reshaping fire policies worldwide, with expanded investments in a wide range of fuel reduction strategies. In many fire prone regions, especially in the Mediterranean basin, fuel management programs have relied on fuel break networks for decades to facilitate fire suppression and reduce area burned and damage. By contrast, on the fire prone federal forests in the western United States, fuel management is guided primarily by landscape restoration goals, including improving fire resiliency such that wildfires can be managed for ecological benefit, and suppression is used more as a tool to shape burn patterns and less to extinguish fires. New policies in both fire systems are now calling for hybrid approaches that rely on both types of investments and efficient allocation of alternative spatial treatment patterns: linear networks versus patches across the landscape. However, studies that combine these strategies and examine alternative co-prioritization outcomes and potential synergies are largely non-existent. Here, we analyzed scenarios for implementing both types of treatments in concert while varying the prioritization metrics for one type or the other on a western United States national forest. We measured the response related to both treatment strategies including fire intersection rate, improvement in forest resiliency, and net revenue. We found that projects with benefits to both strategies can be identified and mapped independently of the implementation scenario and restoration objective. However, scenarios prioritized for fuel breaks preceding restoration resulted in the identification of more projects that met the criteria for providing dual benefits. The study is a rare example of optimizing hybrid fuel treatment projects that serve both restoration and fire protection goals with different spatial treatment designs.
PubDate: 2024-07-30T00:00:00Z
- Application of GM (1,1) to predict the dynamics of stand carbon storage in
Pinus Kesiya var. langbianensis natural forests
Authors: Chunxi Gu, Zhenyan Zhou, Chang Liu, Wangfei Zhang, Zhengdao Yang, Wenwu Zhou, Guanglong Ou
Abstract: Amid global carbon reduction and climate action, precise forest carbon storage estimation is crucial for comprehending the carbon cycle. This study forecasts P. kesiya var. langbianensis forests’ 2030 stand carbon storage using data from 81 permanent plots across three Yunnan Province forest surveys and remote sensing. Findings: (1) In 2000, storage ranged from 26 to 38 t·hm−2. Central areas had higher values; southwest and southeast exceeded northwest and northeast. By 2010, storage grew eastward, receded northward. By 2020, east storage declined, southwest rose. (2) GM (1,1) model: posterior difference C 0.001, R2 power function model 0.945, GM (1,1) p value 0.999, power function model p value 0.997. (3) Predictions: Cosivarang border forest’s 2030 carbon stock 2850.804 t·hm−2, up 103.463 t·hm−2 from 2000. At 2022’s certified Emission Reduction carbon price of 60 yuan/ton, 2030’s carbon asset value per unit (t·hm−2) approx. 6207.78 Yuan, compared to 2000. Integrating gray system theory, especially GM (1,1) model, robustly addresses “small data and uncertainty” system challenges. Introducing GM (1,1) gray theory in forestry research offers fresh insight into forest carbon sink dynamics.
PubDate: 2024-07-26T00:00:00Z
- Forest zone and root compartments outweigh long-term nutrient enrichment
in structuring arid mangrove root microbiomes
Authors: Valerie Hsiao, Natalia G. Erazo, Ruth Reef, Catherine Lovelock, Jeff Bowman
Abstract: Mangroves offer many important ecosystem services including carbon sequestration, serving as nursery grounds to many organisms, and acting as barriers where land and sea converge. Mangroves exhibit environmental flexibility and resilience and frequently occur in nutrient-limited systems. Despite existing research on mangrove microbiomes, the effects of nutrient additions on microbial community structure, composition, and function in intertidal and landward zones of mangrove ecosystems remain unclear. We utilized a long-term nutrient amendment study in Exmouth Gulf, Western Australia conducted in two zones, the intertidal fringe and supralittoral scrub forests, dominated by Avicennia marina. Root samples were fractionated into rhizosphere, rhizoplane and endosphere compartments and analyzed by 16S rRNA gene amplicon sequencing to determine the effects of nutrient stress on community structure and function. Our data showed species richness and evenness were significantly higher in the scrub forest zone. PERMANOVA analysis revealed a significant effect of nutrient enrichment on beta diversity (p = 0.022, R2 = 0.012) in the fringe forest zone only. Cylindrospermopsis, which has been associated with harmful algal blooms, was found to be significantly enriched in fringe phosphate-fertilized plots and nitrogen-fixing Hyphomicrobiales were significantly depleted in the scrub nitrogen-fertilized plots. Meanwhile, root compartments and forest zone had a greater effect on beta diversity (p = 0.001, R2 = 0.186; p = 0.001, R2 = 0.055, respectively) than nutrient enrichment, with a significant interaction between forest zone and root compartment (p = 0.001, R2 = 0.025). This interaction was further observed in the distinct divergence identified in degradative processes of the rhizosphere compartment between the two forest zones. Degradation of aromatic compounds were significantly enriched in the fringe rhizosphere, in contrast to the scrub rhizosphere, where degradation of carbohydrates was most significant. Despite the highly significant effect of forest zone and root compartments, the long-term effect of nutrient enrichment impacted community structure and function, and potentially compromised overall mangrove health and ecosystem stability.
PubDate: 2024-07-25T00:00:00Z
- Analysis of mangrove distribution and suitable habitat in Beihai, China,
using optimized MaxEnt modeling: improving mangrove restoration efficiency
Authors: Li Lifeng, Liu Wenai, Wang Mo, Cai Shuangjiao, Liu Fuqin, Xu Xiaoling, Tao Yancheng, Xue Yunhong, Jiang Weiguo
Abstract: IntroductionMangroves are an important component of coastal ecosystems, and determining the spatial dispersion of prevalent mangrove species and the most suitable land-use source for mangrove growth is of great importance for judicious restoration and effective conservation approaches. Maximum entropy (MaxEnt) models are well suited for this task; however, the default parameterization such models for distribution prediction has limitations and may produce results with low accuracy, requiring elucidation of useful parameter settings. Further, a focus on predicting only the mangrove distribution is insufficient for mangrove restoration, and clarification of suitable habitats is required. Here, we examined the geographical distribution of six mangrove species in Beihai, China (Aricennia marina, Aegiceras corniculatum, Kandelia obovata, Rhizophora stylosa, Bruguiera gymnorrhiza, and Acanthus ilicifolius).MethodsWe used the ENMTools tool to select 16 variables from environmental factors, including bioclimate, terrain, sediment type, land-use classification, and sea-surface salinity and temperature. Using the selected variables and mangrove distribution data, a MaxEnt model optimized using the “kuenm” package in R was used to establish a mangrove prediction distribution model for Beihai City. Transition analyses of land-use types within suitable zones further clarified their current and potential functional roles.Results and discussionThe spatial occurrences of A. marina, A. corniculatum, and K. obovata were strongly driven by topographical features, those of R. stylosa and B. gymnorrhiza mostly depended on bioclimatic variables, and that of A. ilicifolius was driven mostly by edaphic conditions, notably the substrate type. The predicted optimal suitable area for mangrove growth in Beihai City was 50.76 km2, of which 55.04% are currently officially protected. Unprotected areas suitable for mangrove growth were mainly located in Lianzhou Bay, Tieshangang Bay, Dafengjiang, and Xicun Port. The majority of these regions were derived from land-use transitions from wetlands and aquaculture ponds to forested ecosystems. We suggest that careful development of selected wetland ecosystems and transmutation of aquaculture ponds into forested landscapes are crucial for effective mangrove restoration. Our results will assist in selecting suitable species for mangrove restoration sites and improving mangrove restoration efficiency.
PubDate: 2024-07-24T00:00:00Z
- Addressing the altitudinal and geographical gradient in European beech via
photosynthetic parameters: a case study on Calabrian beech transplanted to
Denmark
Authors: Daniel Provazník, Jan Stejskal, Ole Kim Hansen, Jaroslav Čepl, Eva Roland Erichsen, Jon Kehlet Hansen, Dagmar Zádrapová, Ivana Tomášková
Abstract: European beech (Fagus sylvatica L.) is becoming one of the go-to species in reconstructing declining conifer stands in Europe under climate change. Assisted migration may be considered when looking for suitable beech seedlings. Knowledge about the photosynthetic performance of beech seedlings is fundamental to understanding an essential part of their growth and survival potential in different planting conditions. We investigated the within-provenance variation in photosynthetic performance driven by altitude in contrast to inter-provenance variation given by geographical distance. The experiment was conducted on seedlings replanted in a Danish common garden comprising a cluster of provenances with various altitudinal subgroups transplanted from the Calabria region (Italy) and two local Danish provenances. Provenance and within-provenance variation in chlorophyll fluorescence (ChlF) kinetics, gas exchange (GE), flushing, and senescence were assessed. ChlF measurements revealed within-provenance differences based on altitude of origin and could distinguish between the two Danish provenances. In contrast, GE parameters detected variation in the geographical distance among Italian provenances. High-elevation subgroups of Italian provenances showed the best leaf-level photosynthetic performance in Danish weather conditions with high precipitation levels. Altitude of origin can be a significant source of within-provenance variation. We demonstrated that assessing this variation in young trees may be instrumental in maximizing the potential of provenance variation across diverse planting sites.
PubDate: 2024-07-24T00:00:00Z
- Soil amendment mitigates mortality from drought and heat waves in dryland
tree juveniles
Authors: Jason P. Field, Darin J. Law, Orrin B. Myers, Mallory L. Barnes, David D. Breshears, Kierstin M. Acuña, Xiao Feng, Joseph B. Fontaine, Katinka X. Ruthrof, Juan Camilo Villegas
Abstract: Mortality of tree species around the globe is increasingly driven by hotter drought and heat waves. Tree juveniles are at risk, as well as adults, and this will have a negative effect on forest dynamics and structure under climate change. Novel management options are urgently needed to reduce this mortality and positively affect forest dynamics and structure. Potential drought-ameliorating soil amendments such as nanochitosan – a biopolymer upcycled from byproducts of the seafood industry – may provide an additional set of useful tools for reducing juvenile mortality during hotter droughts. Nanochitosan promotes water and nutrient absorption in plants but has not been tested in the context of drought and heat stress. We evaluated factors affecting mortality risk and rate for dryland Pinus edulis juveniles (2–3 years old) in a growth chamber using a factorial experiment that included ambient and +4°C warmer base temperatures, with and without a 10 day +8°C heat wave, and with and without a nanochitosan soil amendment. The nanochitosan treatment reduced the relative risk of mortality, emphasizing a protective function of this soil amendment, reducing the relative risk of mortality by 37%. Importantly, the protective effects of nanochitosan soil amendment in delaying tree mortality under hotter drought and heat waves provides a new, potentially positive management treatment for tree juveniles trying to survive in the climate of the Anthropocene.
PubDate: 2024-07-24T00:00:00Z
- Correlation of woodfuel production participation among rural households in
the drylands of Ethiopia
Authors: Gonche Girma, Abebaw Shimeles, Tensaye Abate, Deginet Berhanu, Asabeneh Alemayehu, Azmera Belachew
Abstract: Woodfuel production and consumption have been a concern for multiple stakeholders involved in household energy use, deforestation, and climate change. While research into the underlying decision-making process is growing, it remains insufficient. Such a study offers opportunities to develop policies that enable diversification of household energy consumption and livelihood options away from woodfuel use. Policymakers often lack an understanding of factors correlated with households' participation in woodfuel production. Therefore, this study examined the correlation between household participation in woodfuel production and factors that influence households' participation in woodfuel production in dryland areas of Ethiopia. Data were collected from 1,114 purposively selected woodfuel-producing and non-producing households through household surveys, key informant interviews, and focus group discussions. The sample included 775 participant households and 339 non-participant households. The collected data were analyzed using descriptive statistics and a binary logistic regression model. The results revealed that drought and related shocks are the main factors that forced households to participate in woodfuel production. The model results indicated that age, education, landholding, livestock holding, production asset value, ownership of improved cook stoves, number of years lived in the area, distance from the forest, access to forest extension, and institutional membership are statistically significant factors that negatively influence household participation in woodfuel production. On the other hand, household expenditure and drought occurrence positively and significantly influence the participation of households in woodfuel production. The findings of the study suggest that sustainable management and utilization of dryland forest resources require considering socioeconomic, demographic, institutional, and environmental factors correlated with households' decisions to participate in woodfuel production. This can be achieved through sound institutional setups and policy frameworks in the sector.
PubDate: 2024-07-23T00:00:00Z
- White spruce presence increases leaf miner effects on aspen growth in
interior Alaska
Authors: Sean M. P. Cahoon, Colin Maher, Daniel Crawford, Patrick F. Sullivan
Abstract: Alaska’s boreal forests are experiencing rapid changes in climate that may favor deciduous-dominated systems, with important implications for global biogeochemical and energy cycles. However, aspen (Populus tremuloides Michx.) has experienced substantial defoliation from the aspen leaf miner (Phyllocnistis populiella Cham., hereafter ALM) in Alaska, resulting in significant growth reductions. We conducted a tree-ring and Δ13C study to test the hypothesis that moisture limitation may have predisposed aspen to leaf miner damage. Contrary to our hypothesis, differences in climate-growth correlations between relatively severely and lightly affected trees were negligible during the pre-outbreak decades. Stands with greater summer precipitation had more limited ALM impact, however differences among models were small and multiple climate variables were suitable predictors of ALM impact. The strong negative relationship we detected between tree-ring Δ13C and basal area increment (BAI) suggested that interannual variation in Δ13C was driven primarily by variation in photosynthesis, limiting the utility of Δ13C as a tool to detect stomatal responses to moisture-limitation. Instead, we found that larger, faster-growing individuals on gentler slopes showed a stronger absolute reduction in BAI (pre-ALM BAI−post-ALM BAI), but were similar in relative BAI reduction (pre-ALM BAI/post-ALM BAI), with smaller, slower growing trees. Older trees and stands with greater relative abundance of white spruce [Picea glauca (Moench) Voss] had greater relative ALM impact whereas slower growing trees on steeper slopes were less affected. The significant effect of white spruce abundance on ALM impact was likely due to favorable leaf miner overwintering habitat provided beneath white spruce trees, which can lead to increased leaf miner survival and thus greater reductions in aspen growth. Our results illustrate the subtle but complex biotic interaction between microclimate and pest physiology in determining ALM-induced aspen growth reductions, adding important nuance to a hypothesized increase in deciduous tree cover in Alaska’s boreal forest.
PubDate: 2024-07-22T00:00:00Z
- The impact of land use change on carbon storage and multi-scenario
prediction in Hainan Island using InVEST and CA-Markov models
Authors: Jinrui Lei, Le Zhang, Zongzhu Chen, Tingtian Wu, Xiaohua Chen, Yuanling Li
Abstract: As a fundamental element of global carbon storage, the storage carbon in terrestrial ecosystem is significant for climate change mitigation. Land use/cover change (LUCC) is a main impact element of ecosystems’ carbon storage. Evaluating the relation between land use change and carbon storage is vital for lowering global carbon emissions. Taking Hainan Island as an example, this paper employs the InVEST as well as the CA-Markov models to assess and predict how different land use affects carbon storage in various situations from 2000 to 2020 and from 2030 to 2050 on Hainan Island. The influence factors, together with driving mechanisms of carbon storage spatial distribution are quantitatively analyzed as well in this paper. The results demonstrate that, from 2000 to 2020, Hainan Island’s net increase in built land was 605.49 km2, representing a growth rate of 77.05%. Over the last 20 years, Hainan Island’s carbon storage and density have decreased by 5.90 Tg and 1.75 Mg/hm2, respectively. The sharp rise in built land mainly makes the carbon storage decline. From 2030 to 2050, land use changes on Hainan Island are expected to result in differing degrees of carbon storage loss in various scenarios. In 2050, Hainan Island’s carbon storage will decline by 17.36 Tg in the Natural Development Scenario (NDS), 13.61 Tg in the Farmland Protection Scenario (FPS), and 8.06 Tg in the Ecological Protection Scenario (EPS) compared to 2020. The EPS can efficiently maintain carbon sequestration capability, but it cannot effectively prevent cropland area loss. Regarding the carbon storage’s spatial distribution, Hainan Island generally exhibits a pattern of high carbon storages in the low and middle carbon storages in the surrounding areas. Areas with high value are primarily located in Hainan Island’s central and southern mountainous areas, whereas areas with low value are primarily located in surrounding areas with lower elevations, primarily encompassing built land and cropland. Geographic detection presented the spatial differentiation of carbon storage in Hainan Island is mainly influenced by factors like slope, land use intensity, and DEM, as well as its interaction with other factors is significantly strengthened (p
PubDate: 2024-07-19T00:00:00Z
- Effects of mulching and flooding on soil nutrients and bacterial community
structure under Phyllostachys praecox
Authors: Jianshuang Gao, Chaofeng Yang, Shunyao Zhuang, Renyi Gui
Abstract: Phyllostachys praecox is a shallow-rooted bamboo that often encounters hypoxia conditions which could be induced by long-term organic material mulching or flooding. It is important to uncover the effect of mulching and flooding on soil nutrient, ammonia-oxidizing microbes, and bacterial diversity. We set up field pot experiments with three treatments (control, mulching, and flooding) under P. praecox. Mulching or flooding altered soil conditions significantly, and both increased ammonium-nitrogen (NH4+-N), total phosphorus (TP), available P (AP), and available potassium (AK) concentrations, and decreased oxygen (O2) concentrations over control. Flooding increased pH and decreased nitrate-nitrogen (NO3−-N), while mulching decreased soil pH and NO3−-N. As O2 content decreased, archaeal 16S rRNA, amoA gene copies of ammonia-oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) increased. Mulching and flooding decreased Shannon, ACE and Chao 1 diversity when compared with the control, and as the O2 contents decreased, bacterial diversity decreased. Redundancy Analysis revealed O2, NO3−-N, AK, AP, and pH were the major factors driving bacterial community structure. Correlation Analysis showed AK and O2 contents were highly correlated with bacterial community structure. In addition, structural equation modeling indicated that O2 facilitated efficient soil N use mainly through soil pH, AK content, and bacterial diversity. Mulching or flooding exerted great effects on environment factor and bacterial community structure, which could be exploited to facilitate the regulation of soil O2 conditions for sustainable P. praecox production.
PubDate: 2024-07-17T00:00:00Z
- Leaf functional traits of Daphniphyllum macropodum across different
altitudes in Mao’er Mountain in Southern China
Authors: Zhangting Chen, Qiaoyu Li, Zhaokun Jiang, Pengbo Yan, Muhammad Arif
Abstract: Investigating functional traits among mountain species with differing altitude requirements is integral to effective conservation practices. Our study aims to investigate the structural and chemical characteristics of Daphniphyllum macropodum leaves at three altitudes (1100 m, 1300 m, and 1500 m) across southern China to provide insight into changes in leaf functional traits (LFT) as well as plant adaptations in response to changing environmental conditions. Leaf structural characteristics include leaf thickness (LT), leaf area (LA), specific leaf area (SLA), and leaf tissue density (LD), respectively, while chemical properties include carbon-nitrogen-phosphorus (C:N:P) contents and ratios, such as C/N, C/P, and N/P. Our findings demonstrated the significant effect of altitude on both structural (LT, SLA, LD) and chemical aspects (N, C/N, N/P) of LFT. In particular, leaves at 1100 and 1300 m differed greatly, with 1300 m having lower SLA values than 1100 m. Observable trends included an initial increase followed by a decline as the altitude rose. Notable among them were the LT, LD, N, and N/P values at both locations. Traits at 1300 m were significantly higher than at 1100 m; SLA and C/N values displayed an inverse trend, with their lowest values occurring at 1300 m. Furthermore, this research demonstrated various degrees of variation among LFT, with structural traits exhibiting greater fluctuation than chemical traits. Robust correlations were observed among certain traits, such as LT, LD, and SLA. Furthermore, the interdependency relationships between N and C/N, as well as P and C/P, demonstrated interconnectedness. Redundancy analysis indicated that soil factors, specifically P content, exerted the strongest impact on LFT. At 1100 m, D. macropodum employed acquisition strategies; however, at 1300 m, conservation strategies emerged, showing a shift from acquisition strategies at lower altitudes to conservative strategies at higher ones.
PubDate: 2024-07-17T00:00:00Z
- Editorial: Forest transitions: from restoration to conservation and
everything in between
Authors: Claude A. Garcia, Patrick O. Waeber
PubDate: 2024-07-16T00:00:00Z
- Land degradation neutrality and carbon neutrality: approaches, synergies,
and challenges
Authors: M. Amritha Gunawardena, Erandathie Lokupitiya, Prasanthi Gunawardena
Abstract: Land is being degraded rapidly worldwide. United Nations Convention to Combat Desertification in 2015 has invited countries to formulate voluntary targets to achieve Land Degradation Neutrality (LDN). Under the Paris Agreement, a legally binding international treaty adopted in 2015, the world is transitioning toward Carbon Neutrality (CN) with more mitigation actions. This paper intended to review the concepts of land degradation, LDN along with CN emphasizing the degradation types, approaches, models available to analyze, synergies, economic aspects and challenges. The review explores approaches and models available for achieving LDN and CN which are both synergistic, economically efficient and could overcome the common challenges. Land degradation has to focus beyond the traditional definitions to incorporate more persistent and the difficult to restore degradation causes. Such complex land degradation requires specialized LDN approaches. The level of degradation and restoration progress could be analyzed using a variety of modeling approaches including economic models. Approaches for LDN and CN can bring significant synergies for each other. The approach proposed by the present study will provide a logical flow for decision-making while minimizing time and effort and avoiding a piecemeal approach. The approach therefore maximizes the output in relation to the inputs thus enhancing sustainability.
PubDate: 2024-07-16T00:00:00Z
- Carbon storage-driven multi-objective spatial planning: simulation and
practice at the management unit level in Northeast China
Authors: Jun Lu, Hao Zhang
Abstract: In recent years, global attention to forest ecological environment, carbon, wood yield, and biodiversity has been increasing, which requires forest managers to make reasonable forest planning in time and space to meet the needs of multi-objectives and multi-resources. In this study, the resources of business units in Northeast China were analyzed, and the FPS-ATLAS model was established. A multi-objective decision supporting spatial forest planning scheme for 16629.53 ha of forest in Jingouling forest farm of Wangqing Forestry Bureau in Jilin Province was proposed. In this paper, the volume growth model of six forest types was established, and the carbon storage model was introduced to show the total carbon, biomass carbon, dissolved organic carbon, and total soil carbon of the ecosystem. The dynamic change in carbon during the whole planning period has achieved good results. After 20 time periods, the total soil carbon increased to 7,627,208 Mg (+6.63%), the total ecosystem carbon increased to 14,889,876 Mg (+27.51%), the biomass carbon increased to 5,362,779 Mg (+59.70%), and the dissolved organic carbon increased to 9,531,906 Mg (+14.59%). The purpose of this article is to achieve dynamic management of forest resources, meet multiple constraint settings, achieve multiple management objectives, harvest wood products, and ensure the ecological and social functions of forests so that forests ultimately achieve the ideal state of sustainability.
PubDate: 2024-07-15T00:00:00Z
