Response of tree-ring growth to climate at treeline ecotones in the Qilian Mountains,northwestern China

Climate constitutes the main limiting factor for tree-ring growth in high-elevation forests, and the relationship between tree-ring growth and climate is complex. Based on tree-ring chronology and meteorological data, the influence of precipitation, mean temperature and mean minimum temperature at yearly, seasonal and monthly scales on the tree-ring growth of Picea crossifolia was studied at treeline ecotones in the Qilian Mountains, northwestern China. The results show that growing season temperatures of previous and current years are important limiting factors on tree-ring growth, particularly June mean temperature and mean minimum temperature of current year. The precipitations in the previous winter and current spring have a positive correlation, and in the current fall has a negative correlation with tree-ring growth, but these correlations are not significant. Our results suggest that temperature controls tree-ring growth more strongly than precipitation at treeline ecotones in the Qilian Mountains.

Stable isotopes reveal varying water sources of Caragana microphylla in a desert-oasis ecotone near the Badain Jaran Desert

Understanding the variation in a plant's water sources is critical to understanding hydrological processes in water-limited environments. Here, we measured the stable-isotope ratios(δ18 O) of xylem water of Caragana microphylla, precipitation,soil water from different depths, and groundwater to quantitatively analyze the proportion of water sources for the shrub.We found that the water sources of C. microphylla differed with the plant's ages and the seasons. The main water source for young shrubs was upper-soil water, and it showed significant changes with seasonal precipitation inputs. In summer,the proportion contributed by shallow water was significantly increased with increased precipitation inputs. Then, the contribution from shallow-soil water decreased with the decline in precipitation input in spring and autumn. However, the adult shrubs resorted to deep-soil layers and groundwater as the main water sources during the whole growing season and showed much less seasonal variation. We conclude that the main water source of the young shrubs was upper-soil water and was controlled by precipitation inputs. However, once the shrub gradually grew up and the roots reached sufficient depth, the main water sources change from the upper-soil layer recharged by precipitation to deep-soil water and groundwater, which were relatively stable and abundant in the desert ecosystem. These results also suggest that desert shrubs may be able to switch their main water sources to deep and reliable water sources as their age increases, and this adjustment to water availability carries significant importance for their acclimation to the desert habitat.

A meta-analysis of the impacts of forest logging on soil CO2 efflux

Soil CO2 efflux,the second largest flux in a forest carbon budget,plays an important role in global carbon cycling.Forest logging is expected to have large effects on soil CO2 efflux and carbon sequestration in forest ecosystems.However,a comprehensive understanding of soil CO2 efflux dynamics in response to forest logging remains elusive due to large variability in results obtained across individual studies.Here,we used a meta-analysis approach to synthesize the results of 77 individual field studies to determine the impacts of forest logging on soil CO2 efflux.Our results reveal that forest logging significantly stimulated soil CO2 efflux of the growing season by 5.02%.However,averaged across all studies,nonsignificant effect was detected following forest logging.The large variation among forest logging impacts was best explained by forest type,logging type,and time since logging.Soil CO2 efflux in coniferous forests exhibited a significant increase(4.38%)due to forest logging,while mixed and hardwood forests showed no significant change.Logging type also had a significant effect on soil CO2 efflux,with thinning increasing soil CO2 efflux by 12.05%,while clear-cutting decreasing soil CO2 efflux by 8.63%.The time since logging also had variable effects,with higher soil CO2 efflux for 2 years after logging,and lower for 3-6 years after logging;when exceeded 6 years,soil CO2 efflux increased.As significantly negative impacts of forest logging were detected on fine root biomass,the general positive effects on soil CO2 efflux can be explained by the accelerated decomposition of organic matter as a result of elevated soil temperature and organic substrate quality.Our results demonstrate that forest logging had potentially negative effects on carbon sequestration in forest ecosystems.

Integrated Forest Biorefinery:Value-added Utilization of Dissolved Organics in the Prehydrolysis Liquor of Prehydrolysis Kraft (PHK) Dissolving Pulp Production Process

The concept of integrated forest biorefineries(IFBRs) has gained significant interest.The prehydrolysis kraft(PHK) dissolving pulp production process is a suitable example of IFBR concept for the production of dissolving pulp and utilization of dissolved hemicelluloses,acetic acid,and lignin in the prehydrolysis liquor(PHL).This review paper highlights recent progress related to the recovery and utilization of dissolved organics(e.g.,hemicelluloses,acetic acid,and lignin) in the PHL of the PHK dissolving pulp production process.Integrated multi-step recovery and separation processes have been developed for this purpose to accommodate the complex nature of the PHL.Potential products,including xylan-based compounds,acetic acid,and lignin,are also discussed in detail.

Impact of soil conditions on the physiological characteristics of maize plants in an arid region, Northwest China

Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures （sandy loam, sand） and three one-time irrigation volumes （60 mm, 20 mm, 0 mm） in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.

Coverless Image Steganography Based on Image Segmentation

To resist the risk of the stego-image being maliciously altered during transmission,we propose a coverless image steganography method based on image segmentation.Most existing coverless steganography methods are based on whole feature mapping,which has poor robustness when facing geometric attacks,because the contents in the image are easy to lost.To solve this problem,we use ResNet to extract semantic features,and segment the object areas from the image through Mask RCNN for information hiding.These selected object areas have ethical structural integrity and are not located in the visual center of the image,reducing the information loss of malicious attacks.Then,these object areas will be binarized to generate hash sequences for information mapping.In transmission,only a set of stego-images unrelated to the secret information are transmitted,so it can fundamentally resist steganalysis.At the same time,since both Mask RCNN and ResNet have excellent robustness,pre-training the model through supervised learning can achieve good performance.The robust hash algorithm can also resist attacks during transmission.Although image segmentation will reduce the capacity,multiple object areas can be extracted from an image to ensure the capacity to a certain extent.Experimental results show that compared with other coverless image steganography methods,our method is more robust when facing geometric attacks.

Processes of runoff in seasonally-frozen ground about a forested catchment of semiarid mountains

Climate warming increases the variability in runoff of semiarid mountains where seasonally-frozen ground is widely distributed.However,what is not well understood are the processes of runoff,hydrological drivers,and freeze-thaw cycles in seasonally-frozen ground in semiarid mountains.To understand how freeze-thaw cycles affect runoff processes in seasonally-frozen ground,we monitored hydrological processes in a typical headwater catchment with seasonally-frozen ground in Qilian Mountain,China,from 2002 to 2017.We analyzed the responses of runoff to temperature,precipitation,and seasonally-frozen ground to quantify process characteristics and driving factors.The results show that annual runoff was 88.5 mm accounting for 25.6%of rainfall,mainly concentrated in May to October,with baseflow of 36.44 mm.Peak runoff occurred in June,August,and September,i.e.,accounting for spring and summer floods.Runoff during the spring flood was produced by a mix of rainfall,melting snow,and melting seasonally-frozen ground,and had a significant correlation with air temperature.Runoff was mainly due to precipitation accumulation during the summer flood.Air temperature,average soil temperature at 0−50 cm depth,and frozen soil depth variable explained 59.60%of the variation of runoff in the thawing period,while precipitation variable explained 21.9%.Thawing-period runoff and soil temperature had a>0.6 correlation coefficient(P<0.05).In the rainfall-period,runoff was also affected by temperature,soil moisture,and precipitation,which explained 33.6%,34.1%and 18.1%,respectively.Our results show that increasing temperature and precipitation will have an irreversible impact on the hydrological regime in mountainous basins where seasonally-frozen ground is widely distributed.

Celulose Paper-based Strapping Products for Green/Sustainable Packaging Needs

Paper products such as corrugated paperboards are the most common green packaging materials, which are renewable, sustainable, recyclable and biodegradable. However, the plastic or metal straps used to secure the carton boxes are not so green. At the end of packaging, the carton boxes can be recycled, but the plastic/metal straps have to be sorted out for disposal separately. This review focuses on: 1) the global trend of green packaging;2) conventional plastic/metal strapping materials for carton boxes;3) conventional market pulp baling with steel wire as the tying materials;4) cellulose fiber-based materials for strapping market pulp bales and carton boxes. New generation of cellulose paper straps are being developed for more challenging applications with superior strength properties and repulpability.

Characterizing stand structure in a spruce forests:effects of sampling protocols

Spatial heterogeneity is an inherent characteristic of natural forest landscapes, therefore estimation of structural variability, including the collection and analyzing of field measurements, is a growing challenge for monitoring wildlife habitat di- versity and ecosystem sustainability. In this study, we investigated the combined influence of plot shape and size on the accuracy of assessment of conventional and rare structural features in two young-growth spruce-dominated forests in northwestern China. We used a series of inventory schemes and analytical approaches. Our data showed that options for sampling protocols, especially the selection of plot size considered in structural attributes measurement, dramatically af- fect the minimum number of plots required to meet a certain accuracy criteria. The degree of influence of plot shape is related to survey objectives; thus, effects of plot shape differ for evaluations of the ＂mean＂ or ＂representative＂ stand structural conditions from that for the range of habitat （in extreme values）. Results of Monte Carlo simulations suggested that plot sizes 〈0.1 ha could be the most efficient way to sample for conventional characteristics （features with relative constancy within a site, such as stem density）. Also, 0.25 ha or even larger plots may have a greater likelihood of capturing rare structural attributes （features possessing high randomness and spatial heterogeneity, such as volume of coarse woody debris） in our forest type. These findings have important implications for advisable sampling protocol （plot size and shape） to adequately capture information on forest habitat structure and diversity; such efforts must be based on a clear definition of which types are structural attributes to measure.

Reversible Data Hiding in Encrypted Images Based on Adaptive Prediction and Labeling

Recently,reversible data hiding in encrypted images(RDHEI)based on pixel prediction has been a hot topic.However,existing schemes still employ a pixel predictor that ignores pixel changes in the diagonal direction during prediction,and the pixel labeling scheme is inflexible.To solve these problems,this paper proposes reversible data hiding in encrypted images based on adaptive prediction and labeling.First,we design an adaptive gradient prediction(AGP),which uses eight adjacent pixels and combines four scanning methods(i.e.,horizontal,vertical,diagonal,and diagonal)for prediction.AGP can adaptively adjust the weight of the linear prediction model according to the weight of the edge attribute of the pixel,which improves the prediction ability of the predictor for complex images.At the same time,we adopt an adaptive huffman coding labeling scheme,which can adaptively generate huffman codes for labeling according to different images,effectively improving the scheme’s embedding performance on the dataset.The experimental results show that the algorithm has a higher embedding rate.The embedding rate on the test image Jetplane is 4.2102 bpp,and the average embedding rate on the image dataset Bossbase is 3.8625 bpp.

Long-term thinning decreases the contribution of heterotrophic respiration to soil respiration in subalpine plantations

Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on R,Rn and Ra.Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning intensity.Thinning significantly decreased winter R,because of the reduction in Rn but had no significant effect on Ra.The temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to Rn and R_(a) dynamics.Thinning increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial activity.Our results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term thinning.Therefore,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) emissions.The increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.

Fe/C micro electrolysis and Fenton oxidation process for the removal of recalcitrant colored pollutants from mid-stage pulping effluent

The pulp and paper industry produces a large amount of colored effluent in the pulping,bleaching,and papermaking processes.The wastewater from the pulp washing and bleaching stages is also known as mid-stage pulping effluent,which is difficult to treat due to its toxicity and dark dolor.This paper reports a novel Fe/C micro-electrolysis process for the treatment of the mid-stage pulping effluent.Results show that this process is effective in removing the color under optimal reaction conditions.Scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR)analyses indicate that the colored pollutants were removed from the wastewater in the Fe/C micro-electrolysis by adsorption,collection and filtration mechanisms.The Fe2+ions produced in the micro-electrolysis process functioned as Fenton’s reagents with H2O2 in the follow-up oxidation stage,which enhanced the removal of chemical oxygen demand(COD)and color.

First International Symposium on Nanocellulosic Materials,Hangzhou,China:Spurring Research and Innovation in Nanocellulosic Materials by Bringing Creative Minds Together

From May 20 to May 21,2017,the 1st International Symposium on Nanocellulosic Materials,hosted by China Technical Association of Paper Industry(CTAPI)and its affiliated Nanocellulose and Materials Committee,was held in Hangzhou,China.This timely symposium attracted about 270 attendees from 8 countries,bringing creative minds together for facilitating more breakthroughs in research,innovation,and commercialization.

About the Journal of Bioresources and Bioproducts (JBB)

The Journal of Bioresources and Bioproducts(JBB)is devoted to publish high-quality peer-reviewed technical research articles on the science and technology related to bio-resources and bio-products.As the petroleum-based economy will be phasing out in a foreseeable period of time,the industrial and scientific societies are paying much attention to the renewable and sustainable resources:bioresources.

Prediction of cognitive scores by joint use of movie-watching fMRI connectivity and eye tracking via Attention-CensNet

Background:Brain functional connectivity under the naturalistic paradigm has been shown to be better at predicting individual behaviors than other brain states,such as rest and doing tasks.Nevertheless,the state-of-the-art methods have found it difcult to achieve desirable results from movie watching paradigm functional magnetic resonance imaging(mfMRI)-induced brain functional connectivity,especially when there are fewer datasets.Incorporating other physical measurements into the prediction method may enhance accuracy.Eye tracking,becoming popular due to its portability and lower expense,can provide abundant behavioral features related to the output of human's cognition,and thus might supplement the mfMRI in observing participants'subconscious behaviors.However,there are very few studies on how to effectively integrate the multimodal information to strengthen the performance by a unified framework.objective:A fusion approach with mfMRI and eye tracking,based on convolution with edge-node switching in graph neural networks(CensNet),is proposed in this article.Methods:In this graph model,participants are designated as nodes,mfMRI derived functional connectivity as node features,and different eye-tracking features are used to compute similarity between participants to construct heterogeneous graph edges.By taking multiple graphs as different channels,we introduce squeeze-and-excitation attention module to CensNet(A-CensNet)to integrate graph embeddings from multiple channels into one.Results:The proposed model outperforms those using a single modality and single channel,and state-of-the-art methods.Conclusions:The results indicate that brain functional activities and eye behaviors might complement each other in interpreting trait-like phenotypes.

Molded fiber and pulp products as green and sustainable alternatives to plastics:A mini review

There are significant incentives/pressures on decreasing the use of plastics and their related prod-ucts in the packaging industry,correspondingly,strong demands are emerging for clean,renew-able,recyclable/biodegradable packaging products.In this context,molded fiber/pulp products have attracted increasing attention,due to their green/sustainable advantages,simply because the raw materials used are plant-based and/or recycled fibers.Many companies have switched their packing practices from plastics to more environmentally friendly products,such as molded fiber products,which already have had and will continue to have obvious effect on packaging industries.This paper initially provides an overview on the general concept of molded pulp prod-ucts,and further summarizes the different types of molded fiber products in terms of natural fiber sources,manufacturing processes,current and emerging applications as well as the environmental sustainability of molded products.

Potential of cellulose-based materials for lithium-ion batteries(LIB)separator membranes

Lithium-ion batteries(LIB)are the dominant power sources for many consumer electronics,and they can also be large-scale power sources/energy storage devices,which can be credited to their advantages:high efficiency,high energy density,long cycling life.The separator membrane is a critical component of LIB.It is an electron insulator between the cathode and anode electrodes in order to prevent electrical short circuits,and it also functions as an ionic conductor to let ions pass freely in the charging and discharging cycles.The critical parameters to meet high quality separator membranes include:high dimensional/thermal/chemical stability,good wettability towards electrolyte,high mechanical strength,appropriate porosity and pore size distribution.Conventionally,plastic materials,such as polyolefin,are the main materials for manufacturing LIB separator membrane.However,polyolefin separator s have a number of drawbacks such as poor thermal stability and wettability.Cellulosic materials have unique properties,and can meet the quality specifications of LIB separator membranes;in addition,they are abundant,low cost,biodegradable,renewable and sustainable.Therefore,cellulose and its related materials can be promising alternatives to replace polyolefin for LIB separator membranes.In this short review,relevant literature on the topic was reviewed and further development/improvement of cellulose-based LIB separator membrane will be discussed.

Effect of magnesium hydroxide as cigarette paper filler to reduce cigarette smoke toxicity

The use of magnesium hydroxide(Mg(OH)_(2))was proposed as a filler to replace part of the calcium carbonate(CaCO_(3))in cigarette paper and reduce the toxicity of the smoke from cigarettes.Physical property changes and smoke reducing ability of this possible substitution were effectively studied.The results showed that adding 10%Mg(OH)_(2) could meet the requirements of the physical property of the cigarette paper.Moreover,with the addition of Mg(OH)2 as a filler in the cigarette paper,the pyrolysis temperature of the cigarette paper decreased,while the porosity and specific surface area increased.As a result,the main-stream smoke had a lower smoke total particle matter(STMP),tar,nicotine and carbon monoxide content,and the side-stream smoke also had a lower STMP.

Potassium hydroxide based biorefinery concepts for non-wood bioresources

The paper and paperboard production in 2016 in the world was 110.07 million tones.1 Bangladesh consumes only about 3.5~4 kg paper and board products per capita,while the developed countries consume about 300 kg/capita.Bangladesh’s consumption is also much lower than the world’s average(@50 kg/capita)and the Asia’s average(@50 kg/capita).2 To reach the world’s or Asia’s level,Bangladesh’s consumption of paper and board products needs to increase 10 folds.As forest resources are very limited in Bangladesh,alternative fibrous raw materials are required to achieve this goal.Therefore many studies have been carried out on alternative raw materials available in Bangladesh.

Nanocellulosic materials:research/production activities and applications

Nanocelluloses have emerged as novel materials and attracted significant interest from both academia and industry.Nanocelluloses can now be produced at pilot plant and pre-commercial scales,and even at commercial scales in some regions in the world.Successful commercial applications of nanocelluloses have entered commercial stages though their full potentials are yet to be developed.In this short communication,the applications of these nanomaterials are high-lighted,including high-volume applications(e.g.,paper,textiles),high-value applications(e.g.,aerogels and structure materials for aerospace),and novel/emerging applications(e.g.,organic light emitting diodes,photonic films).Close collaboration between industries and the academic world would facilitate the development of commercial markets for using nanocelluloses in existing/new areas.