Pitfalls in forest carbon sink projection

Global forests are increasingly crucial for achiev-ing net-zero carbon emissions,with a quarter of the miti-gation efforts under the Paris Climate Agreement directed towards forests.In China,forests currently contribute to 13%of the global land’s carbon sink,but their stability and per-sistence remain uncertain.We examined and identified that published studies suffered from oversimplifications of eco-system succession and tree demographic dynamics,as well as poor constraints on land quality.Consequently,substan-tial estimations might have been suffered from underrepre-sented or ignored crucial factors,including tree demographic dynamics,and disturbances and habitat shifts caused by global climate change.We argue that these essential factors should be considered to enhance the reliability and accuracy of assessments of the potential for forest carbon sinks.

Demographic changes in China’s forests from 1998 to 2018

Background: Tree demography is an essential indicator of various forest ecosystem services, and understanding its changes is critical for the sustainable management of forests. During the past four decades, China implemented unprecedented forest restoration projects, which altered tree demography by increasing the number of trees and introducing new species. However, it remains unclear how species composition has changed in China in response to the past forest restoration and demographical processes.Methods: We applied Forest Stability Index(FSI) and the relative change of FSI(%FSI) to describe the population dynamics of tree species and structure in China since 1998, using field-survey data collected from over 200,000plot-records from the 6th to 9th National Forest Inventories(NFIs).Results: The overall populations of both natural and planted forests have grown rapidly from 1998 to 2018, while the range of changes in the relative tree density was more variable for natural forests(ranging from-8.53% to42.46%) than for planted forests(ranging from-1.01% to 13.31%). The populations declined only in some of the tree species, including Betula platyphylla, Ulmus pumila, and Robinia pseudoacacia. In contrast, the populations of trees in the largest size-class either remained stable or expanded.Conclusions: Tree density of China?s forests(both natural and planted forests) generally expanded and the overall populations increased in most size classes, with greater increases occurred in planted forests. In contrasting to the global decline trends of large diameter trees, here we found no apparent decline for trees in the largest size-class in China, highlighting China?s success in improving forest health and forest adaptations to climate change. We advocate for more studies to reveal the mechanisms of the changes in tree demography, which will help to improve forest ecosystem services such as the carbon sequestration capacity.

Spatiotemporal variations of ozone exposure and its risks to vegetation and human health in Cyprus:an analysis across a gradient of altitudes

Ground-level ozone(O_(3)) aff ects vegetation and threatens environmental health when levels exceed critical values,above which adverse eff ects are expected.Cyprus is expected to be a hotspot for O_(3)concentrations due to its unique position in the eastern Mediterranean,receiving air masses from Europe,African,and Asian continents,and experiencing a warm Mediterranean climate.In Cyprus,the spatiotemporal features of O_(3) are poorly understood and the potential risks for forest health have not been explored.We evaluated O_(3) and nitrogen oxides(NO and NO 2)at four regional background stations at different altitudes over 2014−2016.O_(3) risks to vegetation and human health were estimated by calculating accumulated O_(3)exposure over a threshold of 40 nmol mol^(−1)(AOT40)and cumulative exposure to mixing ratios above 35 nmol mol^(−1)(SOMO35)indices.The data reveal that mean O_(3)concentrations follow a seasonal pattern,with higher levels in spring(51.8 nmol mol^(−1))and summer(53.2 nmol mol^(−1))and lower levels in autumn(46.9 nmol mol^(−1))and winter(43.3 nmol mol^(−1)).The highest mean O_(3)exposure(59.5 nmol mol^(−1)) in summer occurred at the high elevation station Mt.Troodos(1819 m a.s.l.).Increasing(decreasing)altitudinal gradients were found for O_(3)(NO x),driven by summer–winter diff erences.The diurnal patterns of O_(3) showed little variation.Only at the lowest altitude O_(3) displayed a typical O_(3) diurnal pattern,with hourly diff erences smaller than 15 nmol mol^(−1).Accumulated O_(3) exposures at all stations and in all years exceeded the European Union’s limits for the protection of vegetation,with average values of 3-month(limit:3000 nmol mol^(−1)h)and 6-month(limit:5000 nmol mol^(−1)h)AOT40 for crops and forests of 16,564 and 31,836 nmol mol^(−1)h,respectively.O_(3) exposures were considerably high for human health,with an average SOMO35 value of 7270 nmol mol^(−1) days across stations and years.The results indicate that O_(3) is a major environmental and public health issue in Cyprus,and policies must be adopted to mitigate O_(3) precursor emissions at local and regional scales.

Ozone pollution threatens bird populations to collapse:an imminent ecological threat?

While bird populations are declining,the factors associated with this decline are unclear.Based on laboratory experiments,air pollution has long been recognized as a factor causing oxidative stress and adversely aff ecting bird health.Recently,studies employing an epidemiological approach have reported signifi cant declines in avian populations in Central Europe and the United States due to air pollution,and ozone in particular.We advocate that urgent actions are needed to mitigate these eff ects,which threaten biodiversity and environmental health,and propose a series of measures which can enlighten the path toward mitigating air pollution eff ects on avian populations.

Effect size in papers published by the Journal of Forestry Research:A missing treasure?

P values based on standard hypothesis testing are commonly reported in articles published by the Journal of Forestry Research(JFR).However,effect sizes are barely used and reported,even if they are of direct relevance to the primary questions of many of the published studies.The incorporation of effect sizes in studies published by JFR should be encouraged and promoted.Inclusion of effect sizes as a requirement in the journal guidelines will facilitate a major change in the way data are tested and interpreted,with the ultimate goal to exempt researchers from the custom of drawing conclusions merely based upon a dichotomous statistical result(P value).Such a policy can also lead to more informed decisions of whether identified effects are of practical relevance to the forestry.

Testing phaeophytinization as an index of ozone stress in trees

Ground-level ozone pollution is a menace for vegetation in the northern hemisphere,limiting photosynthetic pigments and suppressing photosynthesis in trees and other types of plants.Phaeophytinization is the process of converting chlorophylls into phaeophytins,for example by acidifi cation.Ozone is a highly oxidizing molecule and well known to degrade chlorophylls;however,the eff ect of ozone on phaeophytinization in leaves of higher plants is largely unknown.To reveal ozone eff ect on phaeophytinization and evaluate the potential of phaeophytinization as an index of ozone stress in trees,the absorbance at the optical density of 665 nm was measured before(OD_(665))and after(OD_(665a))acidifi cation in three independent experiments with nearly 30 conditions of ozone exposure.Both current ambient and elevated ozone widely aff ected phaeophytinization,as indicated by decreases or increases in the phaeophytinization quotient OD_(665)/OD_(665a).These eff ects were commonly moderate to large in magnitude and practically signifi cant,and occurred even in ozone-asymptomatic leaves.It emerges that the ozone eff ect on phaeophytinization is bimodal,likely depending on the intensity of ozone stress.These results indicate a promising feature of OD_(665)/OD_(665a)as a thorough index of ozone stress in the future,but further studies are needed to reveal the underlying biochemical mechanisms of the bimodal eff ect on phaeophytinization.

Single and combined eff ects of fertilization,ectomycorrhizal inoculation,and drought on container-grown Japanese larch seedlings

Climate change can intensify drought in many regions of the world and lead to more frequent drought events or altered cycles of soil water status.Therefore,it is important to enhance the tolerance to drought and thus health,vigor,and success of transplantation seedlings used in the forestry by modifying fertilization and promoting mycorrhization.Here,we sowed seeds of Japanese larch(Larix kaempferi)in 0.2-L containers with 0.5 g(low fertilization;LF)or 2 g(high fertilization;HF)of slow-release fertilizer early in the growing season.One month later,we irrigated seedlings with non-sterilized ectomycorrhizal inoculum(ECM)or sterilized solution(non-ECM),and after about 2 months,plants were either kept well watered(WW;500 mL water/plant/week)or subjected to drought(DR;50 mL water per plant/week)until the end of the growing season.HF largely stimulated plant growth and above-and belowground biomass production,eff ects that are of practical signifi cance,but caused a small decrease in stomatal conductance(Gs 390)and transpiration rate(E 390),which in practice is insignifi cant.ECM treatment resulted in moderate inhibition of seedling growth and biomass and largely canceled out the enhancement of biomass and foliar K content by HF.DR caused a large decrease in CO 2 assimilation,and enhanced stomatal closure and induced senescence.DR also largely depleted foliar Mg and enriched foliar K.Although DR caused a large decrease in foliar P content in LF,it moderately increased P in HF.Likewise,DR increased foliar K in HF but not in LF,and decreased foliar P in ECM plants but not in non-ECM plants.Conversely,ECM plants exhibited a large enrichment in foliar P under WW and had a lower water potential under DR when grown in LF.These results indicate that the drought tolerance and health and vigor of Japanese larch seedlings can be modifi ed by soil fertility and soil microorganisms.This study provides a basis for new multifactorial research programs aimed at producing seedlings of superior quality for forestation under climate change.

Sensitivity of forest phenology in China varies with proximity to forest edges

Background:Shifts in forest phenological events serve as strong indicators of climate change.However,the sensitivity of phenology events to climate change in relation to forest origins has received limited attention.Moreover,it is unknown whether forest phenology changes with the proximity to forest edge.Methods:This study examined the green-up dates,dormancy dates,time-integrated NDVI(LiNDVI,a measure of vegetation productivity in growing season),and their sensitivities to climatic factors along the gradients of distance(i.e.proximity)to forest edge(0–2 km)in China's natural forests(NF)and planted forests(PF).For the analysis,field-surveyed data were integrated with Moderate Resolution Imaging Spectroradiometer(MODIS)NDVI from 2000 to 2022.Results:Our results reveal that PF had earlier green-up dates,later dormancy dates,and higher LiNDVI than NF.However,green-up sensitivities to temperature were higher at the edges of NF,whereas no such pattern was observed in PF.Conversely,the sensitivity of dormancy dates remains relatively stable from the inner to the edge of both NF and PF,except for a quadratic change in dormancy date sensitivity to precipitation found in NF.Additionally,we found that the green-up sensitivity to temperature increased with decreasing proximity to edge in NF evergreen forests,while it showed the opposite trend in PF evergreen forests.Furthermore,we observed that the precipitation impact on green-up dates shifts from postponing to advancing from the inner to the edge of NF,whereas precipitation dominantly postpones PF's green-up dates regardless of the proximity to edge.The LiNDVI exhibits higher sensitivity to precipitation at the edge areas,a phenomenon observed in NF but not in PF.Conclusions:These results suggest that the responses of forests to climate change vary with the distance to the edge.With increasing edge forests,which results from fragmentation caused by global changes,we anticipate that desynchronized phenological events along the distance to the edge could alter biogeochemical cycles and reshape ecosystem services such as energy flows,pollination duration,and the tourism industry.Therefore,we advocate for further investigations of edge effects to improve ecosystem modelling,enhance forest stability,and promote sustainable tourism.

Zeno’s Paradoxes and Lie Tzu’s Dichotomic Wisdom Explained with Alpha Beta (αβ) Asymptotic Nonlinear Math (Including One Example on Second Order Nonlinear Phenomena)

Zeno’s paradoxes are a set of philosophical problems that were first introduced by the ancient Greek philosopher Zeno of Elea. Here is the first attempt to use asymptotic approach and nonlinear concepts to address the paradoxes. Among the paradoxes, two of the most famous ones are Zeno’s Room Walk and Zeno’s Achilles. Lie Tsu’s pole halving dichotomy is also discussed in relation to these paradoxes. These paradoxes are first-order nonlinear phenomena, and we expressed them with the concepts of linear and nonlinear variables. In the new nonlinear concepts, variables are classified as either linear or nonlinear. Changes in linear variables are simple changes, while changes in nonlinear variables are nonlinear changes relative to their asymptotes. Continuous asymptotic curves are used to describe and derive the equations for expressing the relationship between two variables. For example, in Zeno’s Room Walk, the equations and curves for a person to walk from the initial wall towards the other wall are different from the equations and curves for a person to walk from the other wall towards the initial wall. One walk has a convex asymptotic curve with a nonlinear equation having two asymptotes, while the other walk has a concave asymptotic curve with a nonlinear equation having a finite starting number and a bottom asymptote. Interestingly, they have the same straight-line expression in a proportionality graph. The Appendix of this discussion includes an example of a second-order nonlinear phenomenon. .

Does the root to shoot ratio show a hormetic response to stress? An ecological and environmental perspective

Root/shoot(R/S)ratio is an important index for assessing plant health,and has received increased attention in the last decades as a sensitive indicator of plant stress induced by chemical or physical agents.The R/S ratio has been discussed in the context of ecological theory and its potential importance in ecological succession,where species follow different strategies for above-ground growth for light or below-ground competition for water and nutrients.We present evidence showing the R/S ratio follows a biphasic dose–response relationship under stress,typical of hormesis.The R/S ratio in response to stress has been widely compared among species and ecological succession classes.It is constrained by a variety of factors such as ontogeny.Furthermore,the current literature lacks dose-response studies incorporating the full dose–response continuum,hence limiting scientific understanding and possible valuable application.The data presented provide an important perspective for new-generation studies that can advance current ecological understanding and improve carbon storage estimates by R/S ratio considerations.Hormetic response of the R/S ratio can have an important role in forestry for producing seedlings with desired characteristics to achieve maximum health/productivity and resilience under plantation conditions.

Forest management required for consistent carbon sink in China’s forest plantations

Background:Forest is the largest biomass carbon(C)pool in China,taking up a substantial amount of atmospheric carbon dioxide.Although it is well understood that planted forests(PFs)act as a large C sink,the contribution of human management to C storage enhancement remains obscure.Moreover,existing projections of forest C dynamics suffer from spatially inconsistent age and type information or neglected human management impacts.In this study,using developed PF age and type maps and data collected from 1371 forest plantation sites in China,we simulated biomass C stock change and quantified management impacts for the time period 2010-2050.Results:Results show that future forest biomass C increment might have been overestimated by 32.5%-107.5% in former studies.We also found that age-related growth will be by far the largest contributor to PF biomass C increment from 2010 to 2050(1.23±0.002 Pg C,1 Pg=10^(15) g=1 billion metric tons),followed by the impact of human management(0.57±0.02 Pg C),while the contribution of climate is slight(0.087±0.04 Pg C).Besides,an additional 0.24±0.07 Pg C can be stored if current PFs are all managed by 2050,resulting in a total increase of 2.13±0.05 Pg C.Conclusions:Forest management and age-related growth dominate the biomass C change in PFs,while the effect of climatic factors on the accumulation is minor.To achieve the ambitious goal of forest C stock enhancement by 3.5 Pg from 2020 to 2050,we advocate to improve the management of existing forests and reduce the requests for more lands for forest expansion,which helps mitigate potential conflicts with agricultural sectors.Our results highlight that appropriate planning and management are required for sustaining and enhancing biomass C sequestration in China’s PF.

Ozone disrupts the communication between plants and insects in urban and suburban areas:an updated insight on plant volatiles

Plant-insect interactions are basic components of biodiversity conservation.To attain the international Sustainable Development Goals(SDGs),the interactions in urban and in suburban systems should be better understood to maintain the health of green infrastructure.The role of ground-level ozone(0_(3)) as an environmental stress disrupting interaction webs is presented.Ozone mixing ratios in suburbs are usually higher than in the center of cities and may reduce photosynthetic productivity at a relatively higher degree.Consequently,carbon-based defense capacities of plants may be suppressed by elevated 0_(3) more in the suburbs.However,contrary to this expectation,grazing damages by leaf beetles have been severe in some urban centers in comparison with the suburbs.To explain differences in grazing damages between urban areas and suburbs,the disruption of atmospheric communication signals by elevated 0_(3) via changes in plant-regulated biogenic volatile organic compounds and long-chain fatty acids are considered.The ecological roles of plant volatiles and the effects of 0_(3) from both a chemical and a biological perspective are presented.Ozone-disrupted plant volatiles should be considered to explain herbivory phenomena in urban and suburban systems.

Temperature-induced hormesis in plants

Environmental change attracts particular attention by biologists concerned with the performance of biological systems under stress. To investigate these, dose–response relationships should be clarified. It was previously assumed that the fundamental nature of biological dose–responses follows a linear model, either with no threshold or with a threshold below which no effects are expected to occur in biological endpoints. However, substantial literature, including widespread documentation in plants, has revealed that hormesis commonly occurs. Hormesis is highly generalized and can be utilized as a quantitative measure of biological plasticity. Conditioning induced by adaptive responses also occurs in the framework of hormesis and is of particular importance to environmental change biology with regards to evolutionary adaptations.This paper presents additional evidence for hormetic dose responses induced by temperature in plants. The current understanding on hormesis provides a perspective for next generation environmental change research. Hormesis should have a central role in environmental change biology of vegetation.

Ethylenediurea(EDU)effects on hybrid larch saplings exposed to ambient or elevated ozone over three growing seasons

Ground-level ozone(O_(3))pollution is a persistent environmental issue that can lead to adverse effects on trees and wood production,thus indicating a need for forestry interventions to mediate O_(3) effects.We treated hybrid larch(Larix gmelinii var.japonica×L.kaempferi)saplings grown in nutrient-poor soils with 0 or 400 mg L^(-1) water solutions of the antiozonant ethylenediurea(EDU0,EDU400)and exposed them to ambient O_(3)(AOZ;08:00-18:00≈30 nmol mol^(-1)) or elevated O_(3)(EOZ;08:00-18:00≈60 nmol mol^(-1))over three growing seasons.We found that EDU400 protected saplings against most effects of EOZ,which included extensive visible foliar injury,premature senescence,decreased photosynthetic pigment contents and altered balance between pigments,suppressed gas exchange and biomass production,and impaired leaf litter decay.While EOZ had limited effects on plant growth(suppressed stem diameter),it decreased the total number of buds per plant,an effect that was not observed in the first growing season.These results indicate that responses to EOZ might have implications to plant competitiveness,in the long term,as a result of decreased potential for vegetative growth.However,when buds were standardized per unit of branches biomass,EOZ significantly increased the number of buds per unit of biomass,suggesting a potentially increased investment to bud development,in an effort to enhance growth potential and competitiveness in the next growing season.EDU400 minimized most of these effects of EOZ,significantly enhancing plant health under O_(3)-induced stress.The effect of EDU was attributed mainly to a biochemical mode of action.Therefore,hybrid larch,which is superior to its parents,can be significantly improved by EDU under long-term elevated O_(3) exposure,providing a perspective for enhancing afforestation practices.

Mastering the scientific peer review process:tips for young authors from a young senior editor

Are you a student at a higher institution or an early-career researcher who is striving to understand and master the peer review process so to increase the odds of getting a paper published in the Journal of Forestry Research or another reputable,peer-reviewed,scientific journal?In this paper,a young,senior editor provides a handbook of the peer review process based on his decadal experience in scientific publishing.He covers major information you need to know during the entire process,from selecting journals to completing the proofing of your accepted paper.He introduces key points for consideration,such as avoidance of predatory journals,dubious research practices and ethics,interaction with peers,reviewers,and editors,and the pursuit of aretê.Finally,he points out some common statistical errors and misconceptions,such as P hacking and incorrect effect size inference.He hopes that this paper will enhance your understanding and knowledge of the peer-review process.

thylenediurea(EDU)effects on Japanese larch:an one growing season experiment with simulated regenerating communities and a four growing season application to individual saplings

Japanese larch(Larix kaempferi(Lamb.)Carr.)and its hybrid are economically important coniferous trees widely grown in the Northern Hemisphere.Ground-level ozone(O_(3))concentrations have increased since the preindustrial era,and research projects showed that Japanese larch is susceptible to elevated O_(3)exposures.Therefore,methodologies are needed to(1)protect Japanese larch against O_(3)damage and(2)conduct biomonitoring of O_(3)in Japanese larch forests and,thus,monitor O_(3)risks to Japanese larch.For the first time,this study evaluates whether the synthetic chemical ethylenediurea(EDU)can protect Japanese larch against O_(3)damage,in two independent experiments.In the first experiment,seedling communities,simulating natural regeneration,were treated with EDU(0,100,200,and 400 mg L^(-1))and exposed to either ambient or elevated O_(3)in a growing season.In the second experiment,individually-grown saplings were treated with EDU(0,200 and 400 mg L-1)and exposed to ambient O_(3)in two growing seasons and to elevated O_(3)in the succeeding two growing seasons.The two experiments revealed that EDU concentrations of 200-400 mg L^(-1)could protect Japanese larch seedling communities and individual saplings against O_(3)-induced inhibition of growth and productivity.However,EDU concentrations≤200 mg L^(-1)did offer only partial protection when seedling communities were coping with higher level of O_(3)-induced stress,and only 400 mg EDU L^(-1)fully protected communities under higher stress.Therefore,we conclude that among the concentrations tested the concentration offering maximum protection to Japanese larch plants under high competition and O_(3)-induced stress is that of 400 mg EDU L^(-1).The results of this study can provide a valuable resource of information for applied forestry in an O_(3)-polluted world.

isoAOT40:An improved ozone exposure index based on the Annual Ozone Spectrum Profile(AO3SP)

Abstarct In recognition of the rising threats of groundlevel ozone(O_(3))pollution to forests,agricultural crops,and other types of vegetation,accurate and realistic risk assessment is urgently needed.The accumulated O_(3)exposure over a concentration threshold of 40 nmol mol-1(AOT40)is the most commonly used metric to investigate O3 exposure and its effects on vegetation and to conduct vegetation risk assessment.It is also used by international regulatory authorities for deriving critical levels and setting standards to protect vegetation against surface O_(3).However,fixed periods of the growing season are used universally,yet growing seasons vary with latitudes and elevations,and the periods of plant lifespan also differ among annual species.Here,we propose the concept of the Annual O_(3)Spectrum Profile(AO_(3)SP)and apply it to calculate the profile of AOT40 throughout the year(AAOT40SP,Annual AOT40 Spectrum Profile)using the International Organization for Standardization(ISO)weeks as a shorter window ISO-based accumulated exposure.Using moving time periods of three(for crops)or six(for forests)months,the i so AOT40 behavior throughout the year can be examined as a diagnostic tool for O_(3)risks in the short-or long-term during the lifecycle of local vegetation.From this analysis,AOT40(i so AOT40)that is most representative for the local conditions and specific situations can be identified,depending on the exact growing season and lifecycle of the target vegetation.We applied this novel approach to data from five background monitoring stations located at different elevations in Cyprus.Our results show that the AAOT40SP approach can be used for improved and more realistic assessment of O3 risks to vegetation.The AO_(3)SP approach can also be applied using metrics other than AOT40(exposure-or flux-based),adding a new dimension to the way O_(3)risk to vegetation is assessed.

Engaging in scientific peer review:tips for young reviewers

Are you a student at a higher institution or a graduate who has published his/her first paper in the Journal of Forestry Research or another legitimate scientific journal?If yes,this paper is written specifically for you since you may soon start receiving invitations to act as a referee.If you are an early career reviewer,you may still find this paper enlightening.Based on his experience,a senior editor summarizes some critical information that,in his view,you may need to know.He provides nine main suggestions to have on your radar,and discusses what you should do or not do as a peer reviewer.

Six statistical issues in scientific writing that might lead to rejection of a manuscript

Communication plays an important role in advancing scientific fields and disciplines,defining what knowledge is made accessible to the public,and guiding policymaking and regulation of public authorities for the benefit of the environment and society.Hence,what is finally published is of great importance for scientific advancement,social development,environmental and public health,and economic agendas.In recognition of these,the goal of a researcher is to communicate research findings to the scientific community and ultimately,to the public.However,this may often be challenging due to competition for publication space,although to a lesser extent nowadays that online-only publications have expanded.This editorial introduces six statistics-related issues in scientific writing that you should be aware of.These issues can lead to desk rejection or rejection following a peer review,but even if papers containing such issues are published,they may prevent cumulative science,undermine scientific advancement,mislead the public,and result in incorrect or weak policies and regulations.Therefore,addressing these issues from the early research stages can facilitate scientific advancement and prevent rejection of your paper.

European Union’s imminent ban on glyphosate: Hormesis should be considered in new chemical screening and selection

The European Federation of Food, Agriculture, and Tourism Trade Unions (EFFAT) called for the immediate ban on glyphosate in the 2022 renewal process, promoting the use of natural herbicides and recommending against the use of other harmful or hazardous chemicals. The new chemical testing and selection research agendas should consider the hormetic effects of individual natural herbicides, and their potential mixtures, on targeted and non-targeted organisms to avoid stimulation of pests and negative effects on non-targeted organisms. New scientific research programs are needed to study the effects of mixtures of natural pesticides on soils, plants, animals, and microorganisms within the context of agroforestry.