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Performance of Densified Wood Glulam as Building Bio-Material

Journal of Renewable Materials 2022年第2期10卷 511-526页

作者： Reza Hajihassani Saman Ghahri Seyedeh Masoomeh Zamani Amir Nourbakhsh Wood and Forest Products research Division Research Institute of Forests and RangelandsAgricultural ResearchEducation and Extension Organization(AREEO)Tehran19395-1113Iran research institute of forests and rangelands Agricultural ResearchEducation and Extension Organization(AREEO)Tehran19395-1113Iran

In this research,some practical aspects of densified wood glulam were investigated.For this aim,poplar wood specimens were densified by hygro-thermo-mechanical technique.Glulam specimens were produced by finger joint technique and polyurethane glue was used as resin.Physical and mechanical properties of glulams were investigated according to ASTM D 143-09,ASTM D 905-03 and ISO 8375 standards.Based on obtained results,using this process(steam and pressurize compaction)resulted in improvement of physical and mechanical prop-erties of glulam specimens.Optical microscopic and scanning electron microscopic(SEM)pictures were proved structural changes on wood material during of applied technique.Generally,the increase of wood density and hygrothermal treatment has a positive role on the glulam properties especially its dimensional stability.This tech-nique showed a significant effect on water absorption;the steaming temperature and holding time significantly decreased water absorption but densification process increased this parameter.Also,delamination of specimens was decreased by hygrothermal treatment while densification showed negative effect on delamination.Moreover,modulus of rupture,modulus of elasticity,shear strength and compression strength parallel to grain were decreased by this technique but it is depend to treatment temperature and holding time.Higher temperature and holding time cause to higher decrease in the glulam mechanical strength.

关键词： Wood modification glued laminated timber physical and mechanical properties

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Functional dissimilarity in mixed forests promotes stem radial growth by mitigating tree water deficit

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National Science Review 2024年第3期11卷 55-57页

作者：张宏图艾尤尔.亥热提白云旻郭焱培李珊 Bernhard Schmid Helge Bruelheide 马克平唐志尧 institute of Ecology College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of Ministry of EducationPeking University College of Geography and Tourism Xinjiang Normal University State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences Department of Geography Remote Sensing LaboratoriesUniversity of Zurich institute of Biology/Geobotany and Botanical Garden Martin Luther University Halle-Wittenberg German Centre for Integrative Biodiversity research(iDiv)Halle-Jena-Leipzig

Tree growth is a key component of forest ecosystem functioning and is wellknown to be limited by water availability[1]. It is acknowledged that composition and diversity of co-occurring tree species can mitigate the influence of drought on tree growth through the resource complementarity for water use via niche partitioning and facilitation between different species [2,3].

关键词： RESILIENCE

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The effects of fire and seasonal variations on soil properties in Juniperus excelsa M.Bieb.stands in the Alborz Mountains,Iran

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Journal of Forestry research 2022年第5期33卷 1471-1479页

作者： Nasim Bagheri Delijani Alireza Moshki Mohammad Matinizadeh Hooman Ravanbakhsh Elham Nouri Faculty of Desert Studies Semnan UniversitySemnanIran Dep.of Forestry in Arid Regions Faculty of Desert StudiesSemnan UniversitySemnanIran Agricultural research Education and Extension Organization(AREEO)Research Institute of Forests and RangelandsTehranIran

This study was conducted in Juniperus excels a stands on the southern slopes of Iran’s Alborz Mountains,to determine the effects of fire and seasonal variations on soil physicochemical properties and enzyme activities.A total of 64 composite soil s amples were randomly collected in the spring and fall from two burned and unburned sites at depths of 0-10 and 10-20 cm.The results of a two-way ANOVA analysis indicate that fire increased the organic carbon(OC),total nitrogen(TN),and available phosphorus(P_(ava)) contents of the soil by 16%,59%,and 53%,respectively.Similarly,when burned sites were compared to unburned sites,the activities of acid phosphatase(ACP) and urease enzymes increased by 73% and 12%,respectively.Nevertheless,fire did not affect soil texture,bulk density(BD),pH,electric conductivity(EC),exchangeable potassium(Kexc),or the activities of alkaline phosphatase(ALP) and dehydrogenase.According to two-way ANOVA results,OC,TN,P_(ava),K_(exc),and EC values were significantly higher in the fall,whereas pH and ALP values were significantly higher in the spring.Additionally,phosphorous and dehydrogenase activity were significantly different in selected soil factors at 0-10 and10-20 cm depths.The interaction of fire,season,and soil depth were significant for phosphorous and urease.Moreover,the activity of ALP correlated well with pH(r=0.68),P(r=-0.74),OC(r=-0.53),and TN(r=-0.37),whereas the activity of ACP correlated significantly with OC(r=0.64) and TN(r=0.71).Two years after the fire,soil properties in J.excels a stands had either improved or remained unaffected,returning to pre-fire levels.Additionally,soil chemical properties varied significantly across sampling seasons,which should be considered when comparing and interpreting soil data in future research.

关键词： Dehydrogenase Acid&alkaline phosphatases Seasonal variations Soil physicochemical properties Urease

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Semi-automated detection of rangeland runoff and erosion control berms using high-resolution topography data

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International Soil and Water Conservation research 2024年第1期12卷 217-226页

作者： Li Li Changjiang River Scientific research institute of Changjiang Water Resources Commission Wuhan430010China research Center on Mountain Torrent&Geologic Disaster Prevention Ministry of Water ResourcesWuhan430010China University of Arizona School of Natural Resources and the EnvironmentTucsonAZ85719USA

An inventory of topographic modifications is essential to addressing their impacts on hydrological and morphological processes in human-altered watersheds.However,such inventories are generally lacking.This study presents two workflows for semi-automatic detection of linear earthen runoff and erosion control berms in rangelands using high-resolution topographic data.The workflows consist of initial object identification by applying either morphological grayscale reconstruction(MGR)or the Geomorphon(GEO)method,followed by identification refinements through filters based on objects’horizontal and vertical information.Three sites were selected within the Altar Valley,Arizona,in the southwestern United States.One site was used for developing workflows and optimizing filter thresholds,and the other two sites were used to validate workflows.The results showed that:1)The MGR-based workflow methodology could produce final precision and detection rates of up to 92%and 75%,respectively,and take less than 5 s for a 10.1 km^(2) site;2)The workflow based on the MGR method yielded greater identification accuracy than did the GEO workflow;3)Object length,orientation,and eccentricity were important characteristics for identifying earthen berms,and are sensitive to general channel flow direction and berm shape;4)Manual interrogation of topographic data and imagery can significantly improve identification precision rates.The proposed workflows will be useful for developing inventories of runoff and erosion control structures in support of sustainable rangeland management.

关键词： Earthen berm Rangeland Grayscale morphological reconstruction Geomorphon LiDAR

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Modeling the effect of stand and site characteristics on the probability of mistletoe infestation in Scots pine stands using remote sensing data

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Forest Ecosystems 2024年第3期11卷 296-306页

作者： Luiza Tymińska-Czabańska Piotr Janiec Pawel Hawrylo Jacek Slopek Anna Zielonka Pawel Netzel Daniel Janczyk Jaroslaw Socha Department of Forest Resources Management Faculty of ForestryUniversity of Agriculture in KrakowAl.29 Listopada 46Krakow31-425Poland Forest Management and Geodesy Bureau Ul.Lesnikow 2105-090Sekocin StaryPoland Department of Geoinformatics and Cartography Institute of Geography and Regional DevelopmentFaculty of Earth Sciences and Environmental ManagementUniversity of WroclawPl.Uniwersytecki 1WroclawPoland institute of Geography and Spatial Management Faculty of Geography&GeologyJagiellonian University in KrakowUl.Gronostajowa 730-387Poland Torun Regional Directorate of State forests Ul.Adama Mickiewicza 987-100TorunPoland

Over the past decade,the presence of mistletoe(Viscum album ssp.austriacum)in Scots pine stands has increased in many European countries.Understanding the factors that influence the occurrence of mistletoe in stands is key to making appropriate forest management decisions to limit damage and prevent the spread of mistletoe in the future.Therefore,the main objective of this study was to determine the probability of mistletoe occurrence in Scots pine stands in relation to stand-related endogenous factors such as age,top height,and stand density,as well as topographic and edaphic factors.We used unmanned aerial vehicle(UAV)imagery from 2,247 stands to detect mistletoe in Scots pine stands,while majority stand and site characteristics were calculated from airborne laser scanning(ALS)data.Information on stand age and site type from the State Forest database were also used.We found that mistletoe infestation in Scots pine stands is influenced by stand and site characteristics.We documented that the densest,tallest,and oldest stands were more susceptible to mistletoe infestation.Site type and specific microsite conditions associated with topography were also important factors driving mistletoe occurrence.In addition,climatic water balance was a significant factor in increasing the probability of mistletoe occurrence,which is important in the context of predicted temperature increases associated with climate change.Our results are important for better understanding patterns of mistletoe infestation and ecosystem functioning under climate change.In an era of climate change and technological development,the use of remote sensing methods to determine the risk of mistletoe infestation can be a very useful tool for managing forest ecosystems to maintain forest sustainability and prevent forest disturbance.

关键词： Generalized additive models Tree infestation Mistletoe occurrence ALS UAV Scots pine

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Four decades of full-scale nitrous oxide emission inventory in China

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National Science Review 2024年第3期11卷 137-149页

作者： Minqi Liang Zheyan Zhou Peiyang Ren Han Xiao Xu-Ri Zhongmin Hu Shilong Piao Hanqin Tian Qing Tong Feng Zhou Jing Wei Wenping Yuan School of Atmospheric Sciences Guangdong Province Data Center of Terrestrial and Marine Ecosystems Carbon Cycle Sun Yat-sen University State Key Laboratory of Tibetan Plateau Earth System Resources and Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province Hainan University Sino-French institute for Earth System Science College of Urban and Environmental SciencesPeking University Schiller institute for Integrated Science and Society Department of Earth and Environmental Sciences Boston College institute of Energy Environment and Economy Tsinghua University Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)

China is among the top nitrous oxide（N2O）-emitting countries, but existing national inventories do not provide full-scale emissions including both natural and anthropogenic sources. We conducted a four-decade（1980–2020） of comprehensive quantification of Chinese N2O inventory using empirical emission factor method for anthropogenic sources and two up-to-date process-based models for natural sources. Total N2O emissions peaked at 2287.4（1774.8–2799.9） Gg N2O yr-1in 2018, and agriculture-developed regions, like the East, Northeast, and Central, were the top N2O-emitting regions. Agricultural N2O emissions have started to decrease after 2016 due to the decline of nitrogen fertilization applications, while, industrial and energetic sources have been dramatically increasing after 2005. N2O emissions from agriculture, industry,energy, and waste represented 49.3%, 26.4%, 17.5%, and 6.7% of the anthropogenic emissions in 2020,respectively, which revealed that it is imperative to prioritize N2O emission mitigation in agriculture,industry, and energy. Natural N2O sources, dominated by forests, have been steadily growing from 317.3（290.3–344.1） Gg N2O yr-1in 1980 to 376.2（335.5–407.2） Gg N2O yr-1in 2020. Our study produces a Full-scale Annual N2O dataset in China（FAN2020）, providing emergent counting to refine the current national N2O inventories.

关键词： nitrous oxide four decades anthropogenic sources natural sources

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Competitive effect, but not competitive response, varies along a climatic gradient depending on tree species identity

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Forest Ecosystems 2024年第2期11卷 142-151页

作者： Teresa Valor Lluís Coll David I.Forrester Hans Pretzsch Miren del Río Kamil Bielak Bogdan Brzeziecki Franz Binder Torben Hilmers Zuzana Sitková Roberto Tognetti Aitor Ameztegui Department of Agricultural and Forest Sciences and Engineering(DCEFA) University of LleidaAv.Alcalde Rovira Roure 191E25198 LleidaSpain Joint research Unit CTFC-AGROTECNIO-CERCA Ctra.Sant LlorençKm.225280SolsonaSpain Swiss Federal institute of Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland CSIRO Land and Water GPO Box 1700CanberraACT2601Australia Chair of Forest Growth and Yield Science School of Life Sciences WeihenstephanTechnical University of MunichHans-Carl-Von-Carlowitz-Platz 285354FreisingGermany Forest research Center INIA-CSICCtra.A Coruña Km 7.528040MadridSpain IuFOR Sustainable Forest Management Research InstituteUniversity of Valladolid&INIASpain Department of Silviculture Institute of Forest SciencesWarsaw University of Life SciencesNowoursynowska 159/3402776WarsawPoland Bavarian State institute of Forestry(LWF) Hans-Carl-von-Carlowitz-Platz 1D-85354FreisingGermany National Forest Centre Forest Research InstituteT.G.Masaryka 2296001ZvolenSlovakia Faculty of Agricultural Environmental and Food SciencesFree University of Bozen-Bolzano Piazza Università1 I-39100Bolzano

Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling appr

关键词： Competition coefficient Competition reduction Interspecific competition Intraspecific competition Mixing effects Mixed species forest Neighbourhood models Plant-plant interactions

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A new approach to pedestal differentiation for soil loss estimation-a case study from a burnt area in north-central Portugal

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Journal of Forestry research 2024年第3期35卷 45-54页

作者： Frank G.A.Verheijen Martinho A.S.Martins Sergio A.Prats Jan J.Keizer Centre for Environmental and Marine Studies(CESAM) Department Environment and PlanningUniversity of Aveiro3810-193 AveiroPortugal Mediterranean institute for Agriculture Environment and Development(MED-CHANGE)Institute for Advanced Studies and ResearchUniversity of EvoraPolo da MitraAp.947006-554 EvoraPortugal GeoBiociencias Geotecnologias E Geoengenharias(GEOBIOTEC)Department Environment and PlanningUniversity of Aveiro3810-193 AveiroPortugal

Soil pedestals have long been used as qualitative indicators of soil splash erosion.In rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the first half of the twentieth century.In agricultural lands,forests,and bad-lands,stone-capped pedestals have been used as qualitative and semi-quantitative indicators of active,'extreme'erosion.Little work has been reported on using capstone pedestal data for quantifying soil loss.We postulate that three distinct capstone pedestal types may be present in any given location and that a detailed analysis of a pedestal height histogram may be used to recognize their populations.This analysis can subsequently inform if soil loss can be reliably estimated and if so,which of the existing methods using pedestal height data will provide more accurate results.The three proposed capstone pedestal types are:(1)neo-pedestals formed underneath surface stones exposed by(partial)removal of the soil surface cover;(2)endo-pedestals formed underneath stones that were buried in the soil but have been exposed by erosion;and(3)phoenix-pedestals formed underneath stones from collapsed pedestals.In the pedestal height histogram of any given location,a skew to smaller heights may indicate the existence of endo-and/or phoenix-pedestals,which may be revealed as a bi-(or tri)modal distribution when using a smaller bin size.This concept was applied to a case study where soil loss had been monitored for control plots and mulched plots during a 5-year period following wildfire in a eucalypt plantation.We measured pedestal heights and used methods to quantitatively assess soil loss from soil pedestal data in the available literature.Soil pedestal data at the end of the 5-year period under or overestimated soil loss in the control treatment,with results ranging from 60 to 115%of measured soil loss,depending on the method.It is postulated that phoenix-and endo-pedestals may be a driving factor behind the observed discrepancies.We discuss

关键词： Soil pedestals Mulch Wildfire Soil erosion Char

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Effects of site preparation methods on soil physical properties and outplanting success of coniferous seedlings in boreal forests

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Journal of Forestry research 2024年第2期35卷 70-80页

作者： Aleksey S.Ilintsev Elena N.Nakvasina Alexander P.Bogdanov Northern research institute of Forestry 13 Nikitova Str.Arkhangelsk 163062Russian Federation Department of Silviculture and Forest Management Northern(Arctic)Federal University Named After M.V.LomonosovSevernoy Dviny Emb.17Arkhangelsk 163002Russian Federation

This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites in taiga forests of the European part of Russia.A total of 54 plots were set up to assess seedling survival;root collar diameter,height,and heigh increment were measured for 240 seedlings to assess growth.In the rooting layer,240 soil samples were taken to determine physical properties.The study showed that soil treatment methods had no effect on bulk density and total porosity in Cladina sites.However,reduced soil moisture was noted,particularly in mounds,resulting in increased aeration.In Myrtillus sites,there were increased bulk density,reduced soil moisture,and total porosity in the mounds.Mounding treatment in Polytrichum sites resulted in reduced soil moisture and increased aeration porosity.In the Myrtillus and Polytrichum sites,patch scarification had no effects on physical properties.In Polytrichum sites,survival rates,heights,and heigh increments of bareroot Norway spruce seedlings in mounds were higher than in patches;however,the same did not apply to diameter.In Cladina and Myrtillus sites,there was no difference in growth for bareroot and containerised seedlings with different soil treatments.Growing conditions and soil types should be considered when applying different soil treatment methods to ensure high survival rates and successful seedling growth.

关键词： Boreal forests Mechanical site preparation Patch scarification Mounding Soil properties Containerised seedlings Bareroot seedlings

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The relationship between interannual dry/wet changes and nomadic wars in the Hexi Corridor region of China during the period 241–1912 A.D.

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Science China Earth Sciences 2024年第6期67卷 1922-1931页

作者： Fei TANG Zhilin SHI Qinhua TIAN Xiaogang DU Yong ZHANG Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China institute of Dunhuang Studies Lanzhou UniversityLanzhou 730020China National Climate Center China Meteorological AdministrationBeijing 100081China Longchanghe Station Gansu Qilian Mountain National Nature ReserveZhangye 734400China University of Chinese Academy of Sciences Beijing 100049China

The link between climate and war has long been a topic of great scientific and social interest.In this study,we investigate the influence of climate on warfare in China’s Hexi Corridor region since 241 A.D.Using the superposed epoch analysis of tree-ring data and historical war data,we observe a notable correlation between interannual dry-wet variations and wars instigated by nomadic groups in the Hexi Corridor.However,this relationship is dynamic and influenced by the region’s relative unity.During periods in which the Hexi Corridor was ruled by multiple regimes,wars tended to follow dry climatic conditions,which may be due to the fact that unusual drought during these periods likely heightened competition for resources and land.Conversely,during times of regional unity,wars were more likely to occur when climatic conditions were wet because the expansion of rangelands and the accumulation of resources helped fuel the nomads’outward conquest.These findings underscore the complexity of the relationship between war and climate change.To gain a more comprehensive understanding of this relationship,continuous,high-resolution historical temperature and humidity datasets with broader and more uniform coverage are needed across multiple regions.In addition,collecting and examining disaggregated historical war data for regions with distinct characteristics is essential.

关键词： Drought Interannual dry and wet variations War The Hexi Corridor Tree ring Nomadic groups

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