Chinese Forest Research Articles

The impact of environmental regulations on forest product trade in China

AbstractForest product trade plays an important role in the development of the Chinese forest industry. The trading value of forest product has shown a yearly growth rate of 12% during the last five recent years. Stringent environmental regulations in China have a profound impact on raw material supplies and industrial production in the forest sector; however, their impact on the forest product trade is still unclear. This study applies fixed and random effects models as well as a seemingly unrelated regression model to investigate the impact of environmental regulations on the trade of forest product from 2002 to 2015. The results indicate that the stringent environmental regulations promoted the import but restricted the export of forest product in general. Specifically, the stringent environmental regulations stimulated the import but had an ambiguous impact on the export of the paper product. The stringent environmental regulations had also stimulated the import of wood product but inhibited the export. In contrast, wooden furniture had been affected minimally; only export got slightly negatively affected by environmental regulations.Recommendations for resource managers: Trade‐offs between economic growth and environmental regulations are needed to smoothly promote the forest product trade in China. Paper and wooden furniture product sectors are less likely to be affected by stringent environmental regulations, because high value‐added products could compensate for environmental costs. The wood product sector is more likely to be negatively affected by stringent environmental regulations because environmental costs could severely impact the competitiveness of low value‐added products.

Development of a Tree Growth Difference Equation and Its Application in Forecasting the Biomass Carbon Stocks of Chinese Forests in 2050

Global climate change has raised concerns about the relationship between ecosystems and forests, which is a core component of the carbon cycle and a critical factor in understanding and mitigating the effects of climate change. Forest models and sufficient information for predictions are important for ensuring efficient afforestation activities and sustainable forest development. Based on the theory of difference equations and the general rules of tree growth, this study established a difference equation for the relationship between the ratio of tree diameter at breast height (DBH) to the tree height and age of age of China’s main arbor species. A comparison with equations that represent the traditional tree growth models, i.e., Logistic and Richards equations, showed that the difference equations exhibited higher precision for both fitting and verification data. Moreover, the biomass carbon stocks (BCS) of Chinese forests from 2013 to 2050 were predicted by combining the 8th Chinese Ministry of Forestry and partial continuous forest inventory (CFI) data sets. The results showed that the BCS of Chinese forests would increase from 7342 to 11,030 terra grams of carbon (Tg C) in 2013–2050, with an annual biomass C (carbon) sink of 99.68 Tg C year−1, and they indicated that the Chinese land-surface forest vegetation has an important carbon sequestration capability.

The strength of soil-plant interactions under forest is related to a Critical Soil Depth

Soil properties and terrain attributes are of great interest to explain and model plant productivity and community assembly (hereafter P&CA). Many studies only sample surface soils, and may therefore miss important variation of deeper soil levels. We aimed to identify a critical soil depth in which the relationships between soil properties and P&CA were strongest due to an ideal interplay among soil properties and terrain attributes. On 27 plots in a subtropical Chinese forest varying in tree and herb layer species richness and tree productivity, 29 soil properties in six depth columns and four terrain attributes were analyzed. Soil properties varied with soil depth as did their interrelationships. Non-linearity of soil properties led to critical soil depths in which different P&CA characteristics were explained best (using coefficients of determination). The strongest relationship of soil properties and terrain attributes to most of P&CA characteristics (adj. R2 ~ 0.7) was encountered using a soil column of 0–16 cm. Thus, depending on the biological signal one is interested in, soil depth sampling has to be adapted. Considering P&CA in subtropical broad-leaved secondary forests, we recommend sampling one bulk sample of a column from 0 cm down to a critical soil depth of 16 cm.

MicroRNA and Other Small RNA Sequence Profiling across Six Tissues of Chinese Forest Musk Deer (Moschus berezovskii)

The Chinese forest musk deer (Moschus berezovskii) is an economically important species distributed throughout southwest China and northern Vietnam. Occurrence and development of disease are aggravated by inbreeding and genetic diversity declines in captive musk deer populations. Deep transcriptomics investigation may provide a promising way to improve genetic health of captive and wild FMD population. MicroRNAs (miRNAs), which regulate gene expression by targeting and suppressing of mRNAs, play an important role in physiology and organism development control. In this study, RNA-seq technology was adopted to characterize the miRNA transcriptome signature among six tissues (heart, liver, spleen, lung, kidney, and muscle) in Chinese forest musk deer at two years of age. Deep sequencing generated a total of 103,261,451 (~87.87%) good quality small RNA reads; of them 6,622,520 were unique across all six tissues. A total of 2890 miRNAs were identified, among them 1129 were found to be expressed in all tissues. Moreover, coexpression of 20 miRNAs (>2000RPM) in all six tissues and top five highly expressed miRNAs in each tissue implied the crucial and particular function of them in FMD physiological processes. Our findings of forest musk deer miRNAs supplement the database of transcriptome information for this species and conduce to our understanding of forest musk deer biology.

Policy forum: Challenges and ways forward in implementing “a guide on sustainable overseas forest management and utilization by Chinese enterprises”

In 2009, the Chinese State Forestry Administration (SFA) and the Ministry of Commerce (MOFCOM) jointly issued the voluntary Guide on Sustainable Overseas Forest Management and Utilization by Chinese Enterprises (herein after referred to as “the Guide”). The main aim is to provide guidance to Chinese companies that invest in overseas forestry development and direct them to develop forestry in other countries in a sustainable way, taking into consideration social and environmental impacts. Thus far, the uptake of the Guide in practical strategies and decisions by enterprises, however, has been limited. Thus, this article aims to identify the main causes for the limited application and challenges in practical business. Based on a questionnaire survey and interviews with Chinese companies, this article finds that after years of advocacy and promotion, the awareness of the Guide among Chinese forest enterprises has increased, but the implementation of the Guide still faces challenges. By reviewing the promotion experience of other international non-compulsory guides, this study provides policy recommendations to encourage Chinese companies to follow the Guide and adopt principles of the Guide in their operations abroad.

Denitrification as a major regional nitrogen sink in subtropical forest catchments: Evidence from multi-site dual nitrate isotopes.

Increasing nitrogen (N) deposition in subtropical forests in south China causes N saturation, associated with significant nitrate (NO3- ) leaching. Strong N attenuation may occur in groundwater discharge zones hydrologically connected to well-drained hillslopes, as has been shown for the subtropical headwater catchment "TieShanPing", where dual NO3- isotopes indicated that groundwater discharge zones act as an important N sink and hotspot for denitrification. Here, we present a regional study reporting inorganic N fluxes over two years together with dual NO3- isotope signatures obtained in two summer campaigns from seven forested catchments in China, representing a gradient in climate and atmospheric N input. In all catchments, fluxes of dissolved inorganic N indicated efficient conversion of NH4+ to NO3- on well-drained hillslopes, and subsequent interflow of NO3- over the argic B-horizons to groundwater discharge zones. Depletion of 15 N- and 18 O-NO3- on hillslopes suggested nitrification as the main source of NO3- . In all catchments, except one of the northern sites, which had low N deposition rates, NO3- attenuation by denitrification occurred in groundwater discharge zones, as indicated by simultaneous 15 N and 18 O enrichment in residual NO3- . By contrast to the southern sites, the northern catchments lack continuous and well-developed groundwater discharge zones, explaining less efficient N removal. Using a model based on 15 NO3- signatures, we estimated denitrification fluxes from 2.4 to 21.7kgNha-1 year-1 for the southern sites, accounting for more than half of the observed N removal. Across the southern catchments, estimated denitrification scaled proportionally with N deposition. Together, this indicates that N removal by denitrification is an important component of the N budget of southern Chinese forests and that natural NO3- attenuation may increase with increasing N input, thus partly counteracting further aggravation of N contamination of surface waters in the region.

Effects of elevated UV-B radiation and N deposition on the decomposition of coarse woody debris

Increases in nitrogen (N) deposition and ultraviolet-B (UV-B) radiation play an important role in global climate change. Because coarse woody debris (CWD) represents a sizeable proportion of total carbon (C) pool in forest ecosystems, understanding the response of CWD decomposition to increased UV-B and N deposition become necessary for evaluating forest C storage under global climate change. In this study, we investigated the respiration of CWD (RCWD) in response to increased UV-B and N deposition over a two-year period for two tree species in subtropical Chinese forests: Cunninghamia lanceolata (Lamb.) Hook. (CL) and Cinnamomum camphora (L.) Presl (CC). We found that N and UV-B treatment, alone or in combination, significantly promoted RCWD, which was further magnified by increased temperature. Moreover, the combined treatment (UV-B + N) far exceeded the sum of the individual effects of N and UV-B treatments. Our results indicated that the three components of global climate change (increased UV-B, N deposition, and warming) worked interactively to accelerate CWD decomposition in forest ecosystems, suggesting that the biogeochemical cycling of subtropical forests could be altered greatly in the future, and this alteration must be considered in modelling the effects of global climate change.

Large-scale patterns in forest growth rates are mainly driven by climatic variables and stand characteristics

Comparing the growth rate of natural forest and plantation forest may be useful to better understand rates of carbon sequestration and carbon turnover. However, the large-scale patterns of biomass growth rates in China’s forests are still not well defined. We analyzed the growth rates of forest leaves, branches, stems, and roots across forest communities in China by using data collection, collation, and systematic analysis of published research and our unpublished data. The biomass growth rates in all forests exhibited negative latitudinal trends and negative altitudinal trends, with significant influence from climatic variables and stand characteristics. Stand characteristics explained more variation in growth rates of forest biomass than did climatic variables, and growth rates of forest leaves, branches, stems, and roots varied in relation to climate, stand characteristics, and forest origin. The cross-validated results of stepwise multiple regression (SMR) models and neural network models (NNM) indicated that the prediction accuracy of growth rate of forest biomass by NNM was better than that of the SMR models. Our results improve understanding of the environmental factors affecting Chinese forest growth and inform efforts to model dynamics of carbon accumulation in China’s forests.

Forest edge effect on biomass carbon along altitudinal gradients in Chinese Fir (Cunninghamia lanceolata): A study from Southeastern China

Monitoring and mapping forest carbon is critical for informing climate change mitigation measures. Evidence indicates that forest edges hold less carbon than the forest interior. In this study, using field inventory data from a Chinese fir forest ecosystem in southeast China, the carbon at the forest edge and forest interior at different elevations was measured. The results showed a significant increasing trend in carbon with elevation. The results also revealed that forest edges had significantly lower carbon than the forest interior. Carbon density values varied between 265 Mg C ha−1 at forest edges and 320 Mg C ha−1 at forest interior. The study highlights that ignoring edge effects overestimates carbon density by 9.46%. These findings suggest that edge effects should be given proper consideration during national forest carbon inventory. Furthermore, the authors recommend the establishment of permanent sampling plots along forest edges for precise and accurate carbon accounting.

Latitudinal and climate effects on key plant traits in Chinese forest ecosystems

Abstracts A long-standing goal of ecology and forest management is to understand the environmental controls of resource utilization strategy of plants along geographical gradients. However, the mechanisms that guide this phenomenon, especially along latitude gradients, remain unclear. Using key leaf functional trait data of 1185 species within 120 sites in Eastern and Western China, we quantified the relationships between plant traits, namely leaf area (LA), specific leaf area (SLA), leaf nitrogen content, leaf phosphorus content, leaf dry matter content (LDMC) and leaf delta 13C (d 13C) content, and local climate along the latitude in Eastern and Western China. Our results revealed that: (1) Plant traits showed a wide variation across the study locations in China. The variation in plant traits was strongly correlated with latitude. (2) In Eastern China, latitude alone explained 54% and 53% of the variation in N:P and leaf phosphorus content (Pmass (g/kg)), respectively. In Western China, latitude alone explained 75% of the variation in leaf area. In Eastern China, most plant traits are significantly correlated with each other. However, this phenomenon is not obvious in Western China. (3) Immediate climate factors (mean climate in the month when the leaf traits were sampled) contributes most to explaining functional traits related to leaf nutrients, such as leaf nitrogen content (Nmass (g/kg), Narea (g/cm2)), leaf phosphorus content (Pmass (g/kg), Parea (g/cm2)), and annual mean climate contributes more to explaining functional traits related to leaf survival strategies. (4) In Eastern China, immediate climate and annual mean climate variables can explain the variance of 39.2% and 41.3% of plant traits variation, respectively. In Western China, the effect size of corresponding factors are 23.4% and 25.2%, respectively.

Estimating N2O emissions from soils under natural vegetation in China

BackgroundNatural and managed soils have been identified as the largest sources of atmospheric nitrous oxide (N2O). However, the quantification of N2O emissions from soils under natural vegetation in China and their possible responses to changing climate and atmospheric nitrogen deposition remains uncertain. In particular, information regarding N2O emissions from Chinese shrublands is lacking.MethodThis study used 28 sets of N2O field measurements in China to validate a process-based dynamic nitrogen cycle model (DyN-LPJ), which was then used to investigate the N2O fluxes from soils under natural vegetation in China from 1970 to 2009.ResultsN2O emissions from Chinese forests, grasslands, and shrublands in the 2000s were estimated to be 0.10 ± 0.06 Tg N yr.−1, 0.09 ± 0.09, Tg N yr.−1 and 0.14 ± 0.07 Tg N yr.−1, respectively. Monthly N2O fluxes were linearly correlated with precipitation, and exponentially (Q10 = 3) with air temperature. The total N2O fluxes from natural terrestrial ecosystems in China increased from 0.28 ± 0.03 Tg N yr.−1 in the 1970s to 0.46 ± 0.03 Tg N yr.−1 in the 2000s. Warming and atmospheric nitrogen deposition accounted for 37% (or 0.07 ± 0.03 Tg N) and 63% (0.11 ± 0.01 Tg N) of this increase respectively.ConclusionsOur results indicate that when compared to grassland ecosystems, N2O emissions from forest and shrubland ecosystems contain larger uncertainties due to either their uncertain areal extent or their emission rates. Long-term and continuous field measurements should be conducted to obtain more representative data in order to better constrain shrubland N2O emissions.

Host Phylogeny Is a Major Determinant of Fagaceae-Associated Ectomycorrhizal Fungal Community Assembly at a Regional Scale.

Environmental filtering (niche process) and dispersal limitation (neutral process) are two of the primary forces driving community assembly in ecosystems, but how these processes affect the Fagaceae-associated ectomycorrhizal (EM) fungal community at regional scales is so far poorly documented. We examined the EM fungal communities of 61 plant species in six genera belonging to the Fagaceae distributed across Chinese forest ecosystems (geographic distance up to ∼3,757 km) using Illumina Miseq sequencing of ITS2 sequences. The relative effects of environmental filtering (e.g., host plant phylogeny, soil and climate) and dispersal limitation (e.g., spatial distance) on the EM fungal community were distinguished using multiple models. In total, 2,706 operational taxonomic units (OTUs) of EM fungi, corresponding to 54 fungal lineages, were recovered at a 97% sequence similarity level. The EM fungal OTU richness was significantly affected by soil pH and nutrients and by host phylogeny. The EM fungal community composition was significantly influenced by combinations of host phylogeny, spatial distance, soil and climate. Furthermore, host phylogeny had the greatest effect on EM fungal community. The study suggests that the assembly of the EM fungal community is governed by both environmental filtering and dispersal limitation, with host effect being the most important determinant at the regional scale.

Distinctive distributions and migrations of 239+240Pu and 241Am in Chinese forest, grassland and desert soils

The vertical distributions and downward migrations of the global fallout derived 239+240Pu and 241Am in diverse types of Chinese soils (forest, grassland and desert) were studied. The mean 239+240Pu and 241Am activity concentrations in the investigated soil cores were 0.28–0.69 mBq/g and 0.13–0.37 mBq/g, respectively, while the accumulative inventories were 61.53–138.99 Bq/m2 for 239+240Pu and 28.29–61.05 Bq/m2 for 241Am. The convection-dispersion equation (CDE) was used to calculate the migration parameters of 239+240Pu and higher apparent dispersion coefficients (D) were observed for the acidic forest soils compared with the alkaline grassland and desert soils; meanwhile a compartment model was employed to compare the migration of 239+240Pu and 241Am in successive soil layers which showed that the migration behaviors of 239+240Pu and 241Am were rather similar; both velocities were less than 0.3 cm/y in diverse types of soils and these findings were compatible with those of short-term laboratory simulation experiments in China.

Chlorinated flame retardant Dechlorane Plus: environmental pollution in China

Dechlorane Plus (DP) is a chlorinated flame retardant that is currently in intensive use and has been detected extensively in the environment. In China, the temporal and spatial distribution of DP is characterized by sources of point emissions in the south and diffusion to the north and west, including to remote, high-elevation areas, which are characterized by different climatic conditions and topographies. Thus, relatively high and low concentrations of DP have been observed in areas without significant nearby pollution sources. High DP concentrations have been observed in South China because of the recycling of large amounts of electronic waste and the presence of a DP factory. DP in urban areas is not influenced by atmospheric transportation, whereas DP in rural areas originates from atmospheric transmission from specific sources, such as e-waste recycling areas, which vary seasonally. Furthermore, DP in Chinese forest soils has been observed to preferentially accumulate in the mineral horizon due to leaching by precipitation as well as erosion by weathering in the organic horizon. Although the hazard quotient (HQ) has been estimated to be far from 1 for DP manufacturing operators, the HQ might not reveal deleterious effects on humans. Extremely high DP concentrations have been observed in serum samples from DP manufacturing operators in China. Moreover, different isomer-specific accumulation in terrestrial species, except for aquatic biota, shows that syn-DP is preferentially accumulated. Finally, to achieve better understanding of the mechanisms of DP degradation both in nature and in organisms, further laboratory study is needed.

Variation in Organ Biomass with Changing Climate and Forest Characteristics across Chinese Forests

Forest biomass allocation patterns are important for understanding global carbon cycling and climate change, which might change with environmental conditions and forest characteristics. However, the effects of climate and forest characteristics on biomass allocation fractions (the fraction of total forest biomass distributed in organs) remains unknown. The authors use a large Chinese biomass dataset (1081 forests encompassing 10 forest types) to analyse the responses of biomass allocation fractions to biogeography, climate, and forest characteristics. The authors found that the stem mass fraction significantly increased with age and precipitation and significantly decreased with latitude and temperature. The branch mass fraction significantly decreased with age and density, but significantly increased with temperature and latitude. The leaf mass fraction significantly decreased with age and precipitation and significantly increased with temperature. The root mass fraction significantly increased with latitude and density, and significantly decreased with precipitation. The results suggest that latitude, temperature, precipitation, stand age and density are good predictors of biomass partitioning. These findings support the hypotheses that variation in resource availability constrains organ allocation and provides biogeographically explicit relationships between biomass allocation and both environmental and forest characteristics, which might be used for assessing the impact of changing environmental and forest characteristics on forest carbon dynamics and fixation.

Future biomass carbon sequestration capacity of Chinese forests

Chinese forests, characterized by relatively young stand age, represent a significant biomass carbon (C) sink over the past several decades. Nevertheless, it is unclear how forest biomass C sequestration capacity in China will evolve as forest age, climate and atmospheric CO2 concentration change continuously. Here, we present a semi-empirical model that incorporates forest age and climatic factors for each forest type to estimate the effects of forest age and climate change on total forest biomass, under three different scenarios based on the fifth phase of the Coupled Model Intercomparison Project (CMIP5). We estimate that age-related forest biomass C sequestration to be 6.69 Pg C (∼0.17 Pg C a−1) from the 2000s to the 2040s. Climate change induces a rather weak increase in total forest biomass C sequestration (0.52–0.60 Pg C by the 2040s). We show that rising CO2 concentrations could further increase the total forest biomass C sequestration by 1.68–3.12 Pg C in the 2040s across all three scenarios. Overall, the total forest biomass in China would increase by 8.89–10.37 Pg C by the end of 2040s. Our findings highlight the benefits of Chinese afforestation programs, continued climate change and increasing CO2 concentration in sustaining the forest biomass C sink in the near future, and could therefore be useful for designing more realistic climate change mitigation policies such as continuous forestation programs and careful choice of tree species.

Joint Control of Net Primary Productivity by Climate and Soil Nitrogen in the Forests of Eastern China

The nature and extent of climate and soil nutrient controls in Chinese forests remain poorly resolved. Here, we synthesized the data on carbon–climate–soil in eastern China, and litter N was firstly taken into consideration, to examine the variation of net primary productivity (NPP) and its driving forces. Results showed that NPP had significant latitude pattern and varied substantially across climate zones. Bivariate analyses indicated that mean annual temperature (MAT), mean annual precipitation (MAP), soil N content (Nsoil), and annual litter N (Nre) were the main controlling factors in spatial pattern of forest NPP. Notably, partial general linear model analysis revealed that MAT, MAP, and Nre jointly explained 84.8% of the spatial variation of NPP. Among the three major factors, Nre explained more variation of forest NPP than the other two factors, and MAT and MAP affected NPP mainly through the change of litter N rather than via themselves, highlighting the importance of litter N in estimating forest NPP. However, to accurately describe the pattern of forest NPP in China, more detailed field measurements and methodologies on NPP and relevant confounding factors should be addressed in future studies.

Influencing Factors on the Ecological Protection Behaviors of Entrepreneurial Farmers in Chinese Forest Zones

Following the collective forest tenure reforms in China, many households pursued entrepreneurial activities creating substantial pressure on the environment. This study examines data collected from 462 informants in 10 provinces in Southern China to understand how changes in attitudes toward ecological protection behavior occur. The internal mechanisms of ecological attitudes were explored using structural equation modeling to obtain a function path. Ecological emotion has a direct effect on ecological protection behavior by acting as an intermediary between ecological knowledge and ecological protection. Perceived ecological severity mediates between ecological knowledge and emotion influencing entrepreneurial farmers’ ecological protection behavior. The perception of individual effect is mediated by perceptions of ecological severity and ecological emotion, eventually affecting ecological protection behavior. A model of cognition–emotion–practice is proposed based on the findings.

Applying foliar stoichiometric traits of plants to determine fertilization for a mixed pine-oak stand in the Qinling Mountains, China.

BackgroundThe Chinese Natural Forest Protection program has been conducted nationwide and has achieved resounding success. However, timber importation has increased; therefore, producing more domestic timber is critical to meet the demand for raw materials. Fertilization is one of the most effective silviculture practices used to improve tree and stand growth. However, determining the appropriate type and amount of elements is necessary for effective fertilization of big timber in different forest types and environmental conditions. Stoichiometric theory provides the criteria to assess nutrient limitation in plants and offers important insight into fertilizer requirements of forested ecosystems.MethodsNitrogen (N) and phosphorus (P) concentrations in plants’ leaves, mineral soil, and litter were investigated in a mixed pine-oak stand.ResultsThe big timber rate for Pinus tabuliformis, Pinus armandii and Quercus aliena var. acutesserata is 57.71%, 22.79% and 2.78% of current existing individuals respectively. Foliar N and P concentrations were 9.08 and 0.88 mg g−1, respectively. The N:P in the plants was 10.30. N concentration and N:P in mineral soil decreased from 0–30 cm soil depth. For litter, N and P concentrations were 16.89 and 1.51 mg g−1, respectively, and N:P was 11.51. Concentrations of N and P in mineral soil and litter did not significantly affect plants’leaf concentrations. Similar result was also obtained between litter and mineral soil concentrations. Nitrogen storage in mineral soil was significantly correlated with foliar N:P in the plants.DiscussionFoliar N:P of dominant tree species and the plants, and foliar N concentration in Pinus tabuliformis and P. armandii, and foliar P concentration of P. armandii in the mixed pine-oak stand was lower than that in Chinese and other terrestrial plants. Foliar nutrients in the plants were not affected by soil nutrients. According to the criteria of nutrient limitation for plants, growth of dominant tree species was N limited; therefore, 1.49 t ha−1 pure N should be added to forest land to as fertilizer.

Adapting Chinese Forest Operations to Socio-Economic Developments: What is the Potential of Plantations for Strengthening Domestic Wood Supply?

Over recent decades, China’s forestry sector went through a transition phase characterized by a management and institutional reform process, with a constant rethinking of the ecological and societal role of forests within a unique political system. Nevertheless, despite impressive achievements in forest restoration and conservation efforts, the enhancement of ecosystem services and forest area expansion through plantation development, China was not able to improve its domestic timber supply capacities according to its demands. Consequently, the continually growing wood processing industry is facing a severe demand-and-supply gap, causing high dependencies on timber imports. Outdated forest operations practices, dominated by manual labour, are not able to meet supply demands or to implement new silvicultural strategies for enhancing forest quality and productivity and are a widely unnoted disruption of a sustainable development. Therefore, this review presents the status quo of China’s forest operations sector, how it is shaped by forest policy reforms and recent socio-economic developments. In addition, suggestions are developed how the sector can progress through policy adaptations in order to develop sustainable timber supply capacities based on a domestic plantation sector.