简介:Bothofstraightandincliningpoplarclone107treewereselectedforstudyingmaterialsinthispaper.Theoptimalpulpingconditionswasestablishedbyorthogonalexperimentaldesignbothfornormalwoodandtensionwood,andthequalityofpulpingandpaper-makingbetweennormalwoodandtensionwoodwascomparedwitheachother.Finally,potentialapplicationforimprovingpaperqualityoftensionwoodthroughincreasingbeatingrevolutionswasdiscussed.Theresultshowedthattheoptimalcookingconditionfornormalwoodwasalkaliconcentration15%,thehighesttemperature164℃,timeathighesttemperature75min,andfortensionwooditwasalkaliconcentration13%,thehighesttemperature160℃,timeathighesttemperature40min.Pathcoefficientofeffectofalkaliconcentrationbothonpulpyieldandkappavaluewassignificantatdifferentlevels.Bycomparisonbetweenaverageresultofnormalwoodandtensionwoodinqualityofpulpingandpaper-making,itwasfoundthattensionwoodhadhigherpulpingyieldandlowerkappavaluethannormalwood.Furthermore,forallmechanicalpropertiesofpaper,normalwoodholdhighervaluethantensionwood,andevenneartwotimesthantensionwood,suchasburstindexandtensileindex.However,differenceoftearindexwasquitenarrow.ResultofonewayANOVAshowedthatdifferenceofburstindexandtearindexbetweennormalwoodandtensionwoodwassignificantatthe0.001level,oftearindexwassignificantatthe0.05level.Basedonobservationofcrosssurfaceofpaper,itwasassumedthatcontributionofgelatinouslayertorigidityofsinglefiberhadhamperedcollapseandcompressionoffiberduringpaperformation,whichisessentialforexertingcombinationbetweenfibersinpaper.So,mechanicalpropertiesoftensionwoodpaperweredecreasedaccordingly.However,owingtohighcellulosecontentofgelatinouslayer,tensionwoodwaseasiertopulpingthannormalwood.Mechanicalpropertiesoftensionwoodpapercouldbeimprovedbyincreasingbeatingrevolutions,
简介:许多学者先后对东北林区桦木属的分类进行了深入研究,对种及种下分类等级意见至今不一致,给综合开发利用桦木类群资源造成了混乱。笔者经多年深入林区实践、调查、采集标本,结合种群特征、地理分布、生境特点综合分类,不以蜡叶标本作为唯一依据,鉴定了桦木属种及种下等级,基本上同意傅沛云(1995)对东北林区桦木属的分类。但笔者认为东北白桦(B.mandshurica(Regel)Nakai)应视为独立种,取消栓皮白桦(BetulaplatyphyllaSuk.var.phellodendroidesTung)名称及英吉里岳桦(ermaniiCham.var.yingkiliensisliouetWang)名称,卵叶桦(BetulaovalifoliaRupr)不应该降为柴桦变种(BetulafruticosaPall.),仍为独立种。
简介:林业分类经营实质上是按照森林主导功能的差异将森林分为生态公益林与商品林,分别按各自特点和规律运营的一种经营管理体制和发展模式。实施林业分类经营,可以从根本上转变林业经济体制和经济增长方式,实现市场经济条件下的森林资源合理配置,较好地解决林业作为物质生产部门和公益事业部门双重功能的矛盾,满足社会对森林不同功能的多样性需求。森林分类区划是林业分类经营的基础与前提,本标准是为了指导全国的森林分类区划工作,规范森林的主导功能类型、分类指标和技术指标而制定的。本标准由国家林业局科技司提出。本标准由国家林业局调查规划设计院起草。本标准主要起草人员林进、唐小平、周洁敏、李荣玲、程小玲。