Orthotropic elastic constants of wood

Wood tracheids are essentially tubular structures but wood cross sections are characterized by large numbers of triple points or junctures of wall segments from three adjacent cells. A symmetric triple point is taken as an approximation to the basic unit of wood structure. This element is analysed as a linearly elastic, isotropic body. It is shown that bending effects enhance the deformations arising from simple strains so that the overall response of the element is anisotropic. The resulting stiffnesses are ordered $$E_L \user2{ > }E_R \user2{ > }G_{LR} \sim G_{LT} \user2{ > }E_T \user2{ > }G_{RT} $$ for what are considered to be fairly typical element geometries. It is shown that for all geometries the longitudinal Youngs modulus is proportional to the volume fraction of cell wall material.     

Characteristics of microfibrillated cellulosic fibers and paper sheets from Korean white pine

Microfibrillated cellulosic fibrous product was successfully obtained from Korean white pine (Pinus koraiensis Sieb. et Zucc.) by using two alternative pretreatments (steam and ozone treatments) followed by disk milling (DM). The steam and ozone treatments were effective in extracting some of the hemicelluloses and degrading lignin, respectively, with both types of treatment resulting in the improvement of mechanical fibrillation as a result of loosening of the cell wall structure. The obtained products showed nanoscopic fibrous morphology even though hemicelluloses and lignin components remained. The specific surface area and filtration time were increased using the DM treatment after both treatments, and the values increased further with longer periods of DM. The paper sheets of the fibrillated products after both the alternative treatments had higher tensile properties at the same DM time scale than the sheets of the products obtained without treatment. Tensile strength was further increased by increasing sheet density showing the highest tensile strength and modulus of 125 MPa and 20 GPa, respectively.     

SMALL-DIAMETER KOREAN PINES AND THEIR ROLES INNATURAL KOREAN PINE FOREST

lNTRODUCTloNKorcanpincforcst'asaclimaxofcastlnounta1nsinNortheast-isalt"a}simportantobjcctforforcstcrstostlld}.AIthougllman}'cxpcrtsllax'cn1assi\'cI}'stlldicdthcdy'nal11icsproccssofKorcanpincforest.thcstudlesinsolllcaspcctsstilIIackdcpth'ct'cnl1at'cgaps.Sillccslnall-dianlcterKorcanpincsplayaIinL-lllgIbrlllerandlattcrroIcinKorcanpincforcstd}'llaIl1icsproccss.tl1cstudicsaboutsn1all-dlan1ctcrKorcal1pil1cs-origlnatiol1'gro\Y1l1cllaractcrandthcirrclatiol1stostandstnICt1Ircundoubtcd1}oflbr…     

超声波辅助提取脱脂红松仁中水溶性多糖的研究

采用超声波辅助提取法对脱脂红松仁中水溶性粗多糖的提取工艺进行了研究.通过正交试验,分别考察了提取温度、液料比、提取时间及醇沉浓度4个因素对红松仁多糖提取率的影响,得出优化的工艺条件：提取温度为70℃,液料比为20：1,提取时间为40 min,醇沉浓度为80%,此条件下多糖的提取率为3.65%,平均含量为45.38%.结果表明,超声波辅助提取的效率和含量均优于传统热水浸提法,且具有提取温度低、时间短及效率高的优势.     

红松仁营养成分分析及松仁油制取方法的探讨

分析了松仁的营养成分,并详细阐述了各种营养成分的功能机理,对红松仁系列产品的加工工艺进行了系统的研究。运用CO2超临界萃取技术,对红松松仁油提取条件进行了初步探讨,找出了最佳提取温度、压力指标。     

SECONDARY SUCCESSION OF NATURAL KOREAN PINE FORESTS

ThereisatractofsecondaryforestsinnatUfKoreanghn(Pinuskorniensis)forestndon-FenlinNatUrReserveswithanareaofl8l65.4hIn,locatedinthesouthslopeofXiaOking'anlingMountain.ThisresearchwascAnedoutonthesuccessionofhosstandNATURAL0unS0FwiSTANDSInl93l,therewasawildfireinthevir-ginKoreanPineforests,whichstretchedfromShanggedingalongTangwangffivertonorth-eastuntilstandNo.32OfFenglinNatureRe-serves.Thefiredareawasabout2,44Ohm2.TOdate,thestandsisbroadleavedmixedfOr-estsdOndnatedbywhitebirch(…     

Comparison of methods for extracting high-throughput sequencing RNA from Korean pine seeds

Korean pine(Pinus koraiensis Sieb. et Zucc.) is an ecologically and economically important tree species in East Asia. Molecular studies of seed development of this species are limited due to the lack of effective RNA extraction protocols. This study aimed to obtain an effective method to extract high-quality RNA from Korean pine seeds. The TRIzol kit and CTAB methods were used to extract the total RNA from Korean pine seeds at different developmental stages. The bands of RNA extracted by CTAB were not clear, whereas the bands of RNA extracted by the TRIzol kit were brighter and clearer, indicating higher quality and integrity of the RNA products extracted by the TRIzol kit. The 28 S r RNA band was approximately1.5- to 2-fold brighter than the 18 S r RNA band on the agarose gel electrophoresis. The absorbance value A260/280 was 1.8–2.0, and the absorbance value A 260/230 was [1.9. The Bioanalyzer RNA integrity results showed that the RNA integrity number of the RNA extracted using the TRIzol kit was acceptable for high-throughputsequencing. Therefore, the total RNA extracted using the TRIzol kit method can be used for high-throughput sequencing and other molecular biology experiments.     

Soil CO2 evolution from Korean pine virgin forest at Changbai Mountain

The soil CO₂ evolution rate was measured in a virgin Korean pine forest. The results in June showed that the lowest value of evolution rate was 220 mg/(m²·h) and appeared at 6:00 a.m. The highest value was 460 mg/(m²·h) at 18:00. The rates of CO₂ evolution were related with soil temperature. On the basis of the constructed regression equation and the monthly average values of temperature, the magnitude of CO₂ evolution from Korean pine forest soil was 10.4 t/hm² during a growing season. This project was funded by the Opened Research Station of Changbai Mountain Forest Ecosystem, Chinese Academy of Sciences. Responsible editor: Zhu Hong     

Soil CO_2 evolution from Korean pine virgin forest at Changbai Mountain

InttxiductionCozevolutionfrolnsoilisol1eoftlletl1aj()rprocessesli1globalcarboncycling.II1creaseal11oul1tofCo2inatnlos-phereisPartlyresultedfromtl1edislurba11ceofstabilizedvegetationandlalldused.Sonlege11erali11f`)nnatio11forforestecosystemisavailableo11soilrespirati()l1(Scllle11t-nerandClevel985).Managementpracticeli1forestryclearlyhassignincanteffectedontl1emagnitudeofsoiICozevolution(EWletal.l987).Con1parisol1resuILsofsoilCozevolutionratesatsitesindifferel1tcol1ditiollsllavebeenwellgot…     

红松、红皮云杉及落叶松裸根苗培育技术的探讨

论述了红松、红皮云杉及落叶松裸根苗培育技术,着重强调了几种常用树种裸根育苗在实际营林生产中应用的可能性。     

Ultrasound-associated extraction of seed oil of Korean pine

Experiment on ultrasound- associated extraction of seed oil of Korean pine (Pinus koraiensis) was conducted in Northeast Forestry University, Harbin, China. The factors affecting extraction yield, such as ultrasonic frequency, extracting temperature, extracting time and the ratio of material to liquid (ratio of Korean pine seed to absolute alcohol), were analyzed under specific condition and the optimal extracting parameters were obtained as the ultrasonic frequency 32 000 Hz, the extracting temperature 80℃, the extracting time 50 rain, and the ratio of material to liquid 1: 30. The study demonstrates that ultrasound is a reliable and great efficiency tool for the fast extraction of Korean pine seed oil。     

RESEARCH ON REGENERATION APPROACHES OF KOREAN PINE FORESTS

Broad-lcavedKoreanpincforcstisthcclimaticclimaxconinunitVofnortheastmoun-tainousregionsofChina.AsthemaintreesPecies,Koreanpinehasexccllentwood.AgreatattentionbasbccnpaidtorecoveringtheseforesttyPesafterharvesting.Additional1y,KoreanpineisoneofkeyregcncrationtreesPeCiesinthisregion.TherehasbeenlargeareaofKorcanpincplantations.Howevcr,thercaresomeproblemsncedingtobestUdicdfwtheramongwhichoneistoselectsuitabIeropenerationapproacl1esofKoreanpincforesls.WHATISTHEPROBLEM?ThcnatUralregen…     

红松经济林无性系嫁接配套技术

从4个方面介绍了红松经济林栽培、嫁接、嫁接幼树的抚育管理,以及病虫害防治等一系列无性系嫁接配套技术.     

红松不同部位精油的成分分析及抑菌活性

[目的]植物精油是安全并有良好抑菌效果的天然产物,在食品防腐剂领域潜力巨大.本研究通过对红松不同部位精油成分与抑菌活性的研究,能为开发安全绿色的食品防腐剂及为其在食品、化妆品等领域的应用提供理论基础.[方法]采用水蒸气蒸馏法从红松的松针、松塔、松壳中制备精油,采用气相色谱-质谱(GC-MS)联用技术结合保留指数(RI)...     

ENERGY DISTRIBUTION AND BIOLOGICAL PRODUCTIVITY IN KOREAN PINE PLANTATION

Energycirculatingbetweenliveandenvironmentsystemsformesanenergyflowofaecosystem.Itissignificanttocorrectlyrecognizethepatternofenergyflowinaecosystemfordeterminingthemeasurementofforestmanagement.Thepaperstudiedenergydistributionandtranslationpattern.whichcanprovideatheoreticalbasisforreasonablymanagingkoreanpineplantations.MethodofRescarchThestandinvestigatedisapurekoreanpineplant-ationthatwasplantedinl96l,withspacingofl.Oxl'5m;itwasthinnedfor4timesafterreachingclosureandnowhasadansityofl52…     

Estimation of yield and ultimate strengths of bolted timber joints by nonlinear analysis and yield theory

A finite element nonlinear analysis was conducted on bolted timber joints under lateral loads parallel and perpendicular to the grain. The results obtained from this analysis were compared with the experimental results and calculated values based on the yield theory. The analysis and experiment were performed on double shear bolted joints parallel and perpendicular to the grain with steel side plates and a slotted-in steel plate. It was found from the analysis that the yielding of wood and bolt occurred before the overall yielding of the bolted joint. Shear strength of bolted joints calculated from the yield theory using the embedding yield strength of wood and the yield moment of the bolt showed comparatively good agreement with the shear strength evaluated by 5% offset of the load–slip curve in the experiment and analysis. The shear strength of the bolted joint calculated from the yield theory using the embedding ultimate strength of wood and the ultimate moment of the bolt agreed quite well with the shear strength evaluated by the maximum load up to 15mm slip in the analysis. The former, parallel and perpendicular to the grain, were 11% and 34%, on average smaller than the latter in the experiment.Part of this paper was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002; the Annual Meeting of Architectural Institute of Japan 2002, Ishikawa, August 2002; and the World Conference on Timber Engineering 2002, Shah Alam, Malaysia, August 2002     

Comparative analyses on the litter in Korean pine Mongolian Scots pine and Dahurian Larch plantations

Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine (MSP) and Dahurian larch (DL) plantations in Laoshan Plantation Experiment Station of Maoershan Experiment Forest Farm of Northeast Forestry University. The results are as follows: (1) The nutrient element content and returning amount in litter varies among different fractional compositions and tree species, the total returning amount of all nutrient elements and the returning amount of K, Ca, Mg, N and P are DL > MSP > KP, the returning amount of Cu is DL > KP > MSP, the returning amount of Fe and Mn are MSP > DL > KP; (2) To KP and DL plantations, the main nutrient element returned is dead needles; dead branches, bark scales and dead cones account for a little proportion; whereas to MSP plantation, besides dead needles, dead branches and bark scales also play an important role in the return of nutrient elements; (3) A little deal of dead leaves can provided a great deal of returning amount of nutrient elements.     

超声波辅助提取红松仁油

近年来,超声波辅助提取已成为天然产物分离中一种有效的方法.本文研究了利用超声波辅助提取技术从红松仁中提取红松仁油的工艺条件,系统分析了超声频率、提取温度、提取时间和料液比等参数对红松仁油提取率的影响.结果表明,最佳的提取条件为:超声频率为32 000 Hz,超声温度为80 ℃,超声时间为50 min,料液比为1:30.     

Optimal management of Korean pine plantations in multifunctional forestry

Korean pine is one of the most important plantation species in northeast China.Besides timber,it produces edible nuts and plantations sequester carbon dioxide from the atmosphere.This study optimized the management of Korean pine plantations for timber production,seed production,carbon sequestration and for the joint production of multiple benefits.As the first step,models were developed for stand dynamics and seed production.These models were used in a simulation–optimization system to find optimal timing and type of thinning treatments and optimal rotation lengths.It was found that three thinnings during the rotation period were optimal.When the amount or profitability of timber production is maximized,suitable rotation lengths are 65–70 years and wood production is 5.5–6.0 m~3 ha~(-1) a~(-1).The optimal thinning regime is thinning from above.In seed production,optimal rotation lengths are over 100 years.When carbon sequestration in living biomass is maximized,stands should not be clear-cut until trees start to die due to senescence.In the joint production of multiple benefits,the optimal rotation length is 86 years if all benefits(wood,economic profits,seed,carbon sequestration) are equally important.In this management schedule,mean annual wood production is 5.5 m~2 ha~(-1) and mean annual seed yield 141 kg ha~(-1).It was concluded that it is better to produce timber and seeds in the same stands rather than assign stands to either timber production or seed production.     

红松速生丰产林立地选择技术

选择最佳立地是培育红松人工丰产林的基础,也是一种不增加投入,可望取得较大幅度增产的有效途径。为了更好的实现这一目标,经过系列研究与编制红松人工林的立地指数,进行立地质量综合评价,为营造速生丰产林提供科学依据。