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.     

提高低密度杨桦林林分生产力的经营技术

对低密度的杨桦林经营过程中需要解决的主要技术问题进行了研究，包括上层林及林冠下栽植密度的确定，最小栽植空间的确认以及红松最适宜的透光时间和透光方法。     

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.     

The generation identification and process of digenesis of Korean pine forest

AgcncrationrcfcrstoaIltrccsgencratcdinsamcPCriodoftimc.Tl1isisat`idcl}'ac-ccptedcol1ccpt.a11dtl1c111ostimPOrtantcharac-tcristicofgcncrationisgcncrationintcri'aloflime.TlcbiologicalcontcntisrcIati\'c1}'t'agucwhcnidcntif3'agcncrationonIyb}'mcansoftime.ltisPoi11tcdoutb}By31,lHlI(l985)tl1atagcncrationrcfcrstoalltl1ctrccst`11ichhax'csamcorigination,agc.morPho1og}',ccologica1proPCrt3'andPOsitionincom111unity,sotl1crcarcman}'`"a},stoidcntif3'gcncration.ltisjustbccauscofthcabundanccoftl1cconnota…     

红松幼龄材与成熟材力学性质的差异

本文研究了人工林和天然林红松幼龄材与成熟材力学性质的差异.结果显示,成熟材的所有力学性质均高于幼龄材.幼龄材与成熟材的抗弯弹性模量差异在人工林红松中达0.01水平显著,天然林红松也达到0.01水平显著;人工林红松抗弯强度和弦向横纹抗压强度差异达0.05水平显著.抗弯强度、顺纹抗压强度、横切面硬度和弦向横纹抗压强度4项指标的差异达0.05水平显著.     

Study on dynamics of stem form of Korean pine trees in natural forest stand

INTRODUCTIONThcstcmfonl1ofnaturalKorcanpincforcst.ot\ingtothcsupprcsscdandshadcd,isvcry'difTcrcntt`iththatofplantation.Itis\'cry't'aluabIctostud}'thcstcmfonnforn1orcac-knot`lcdgcabouttl1ctrccd)-nan1icsofnaturalKorcanpinc.n1crcl1asbccnconsidcrabIcrescarchontl1cstc111for111cquationsasatoolforforcstmanagcmcnt,butitalmostbasnorclationshipt`-iththcbiologicalgrowthproccss.soitisx'ery'dimcuIttouscthccquationtoanalxrsisthcd\'amicsofstclllform.Hcrcthcdct'clopmcntofstcmformt"ascxPCctcdfornotonI\…     

阔叶红松林倒木贮量动态研究

本文研究了中国吉林省长白山区阔叶红松林倒木贮量的动态变化规律。阔叶红松林倒木贮量包括其现有倒木及其年输入量等贮量的变化规律。阔叶红松林现有倒木贮量开始为16.25 t·hm-2,以后随时间减少,到100年分解掉其干重的85%左右,300年后所剩无几。倒木年输入量平均约为0.6 t·hm-2,其贮量是随时间而增加,200年后稳定在31 t·hm-2,可保持到该群落的顶级时期。倒木总贮量的变化在初期呈增加趋势,而后随着现有倒木的完全分解,倒木贮量就与其倒木的年输入趋于一致,最后稳定在上述水平上。图4表2参9。     

丰林保护区阔叶红松林红松根腐规律的研究

本文是以丰林保护区阔叶红松成过熟林木为研究对象,通过对红松株数,无腐率、心腐率、边腐率统计结果表明:心腐率随根径的增大而增加,且以林分类型为主要因子而转移,林分中红松成过熟林木无腐朽率为19.4%、心腐率为75.3%、边腐率为5.3%.     

阔叶红松林主要树种幼树对干旱胁迫的响应

以组成我国北方典型阔叶红松林森林生态系统的主要树种水曲柳、红松、蒙古栎、紫椴和核桃楸为研究对象,模拟不同土壤水分变化对树木生物量、光合特征和水分利用率的影响,分析我国北方典型森林生态系统对未来气候干旱化的响应及适应机制,提出北方典型森林生态系统对未来气候变暖引起的对干旱化的响应与适应对策。     

联营林场红松天然母树林的经营

本文对联营林场红松天然母树林的经营谈了一套实践经验 ;红松优良林分的选择标准 ;促进红松母树结实的疏伐 ;如何加强经营管理及组织好林木种子的生产。