透光抚育对红松阔叶林群落结构与生产力的影响

采用样带网格调查方法和群落重要值分析方法，研究透光抚育（全透光、半透光、未透光）对红松阔叶混交林群落（人天混群落）的树种组成结构、径级分布、蓄积量和红松蓄积生产力的影响效果。结果表明：沿由小到大的透光强度，人天混群落中红松重要值依次增大（0．499～1．000），透光有利于人天混群落中红松优势地位增强；红松大径木比例依次增加（0．00％～54．0％），小径木比例依次减少（74．9％～2．7％），透光有利于人天混群落中红松大径木比例提高；群落蓄积量依次增加（60．2475～230．4051m^3／hm^2），红松蓄积生产力依次增加（1．2692～5．3603m^3／hm^2·a），透光有利于人天混群落蓄积量及红松蓄积生产力的提高。     

不同抚育强度的人天混红松林群落植物多样性

采用样带网格调查和多样性指数分析方法,研究了透光抚育(全透光、半透光、未透光)对人天混红松林群落植物多样性(丰富度、多样性指数和均匀度)的影响效果,并与天然次生林群落进行对比分析,定量评价了40年生人天混红松群落植物多样性的恢复效果。结果表明:全透光和半透光群落的物种丰富度较未透光群落增加了8.0%和24.0%,但较天然次生林群落却分别下降了18.2%~27.0%和6.1%~16.2%,半透光抚育更有利于该群落物种丰富度的恢复;全透光和半透光群落的物种多样性指数分别较未透光群落提高了3.38%和20.8%,与相应天然次生林群落的变化幅度分别为-8.70%~8.66%和6.69%~26.98%,也是以半透光抚育方式恢复效果好;全透光、半透光和未透光群落的物种均匀度相近(变化幅度在0.02%~10.7%之间),但三者与天然次生林群落有较大的差异性(变化幅度依次为-5.2%~18.2%、4.9%~30.8%和-5.2%~12.6%),半透光抚育群落物种均匀度最高。     

透光抚育对张广才岭“栽针保阔”红松林群落生产力的影响

介绍了透光抚育对不同立地(不同坡位)上的栽针保阔红松林群落的公顷蓄积和生产力的影响,研究分析如何通过不同强度透光抚育提高栽针保阔红松林群落生产力。     

林隙透光抚育对红松林结构稳定性的影响

以经历过林隙透光抚育的红松人工林为研究对象,利用树种的存活曲线以及重要值两种方法,对林隙透光抚育红松林的结构及稳定程度进行研究的结果表明,抚育后的林分中的主要树种红松、杨树和白桦的存活曲线均接近直线型,表明各主要树种均处于稳定状态;红松的重要值均明显高于阔叶树种,阔叶树种中白桦与杨树的重要值是最高的,红松的重要值与阔叶树重要值总和相当,表明抚育措施在达到保留与培育目的树种红松的前提下,为群落正向演替提供了良好的环境基础,使群落的树种结构得到优化。     

红松人天混交林透光抚育技术研究

红松人天混交林不同的抚育方式、抚育强度对红松生长和林分质量有影响。通过综合评估,对上层阔叶树实行中高强度透光疏伐效果较好,能分别提高红松胸径生长量26.3%和34.8%,提高树高生长量17.1%和11.5%,提升珍贵阔叶树在阔叶树中比例6.5%和10.1%;在相同透光强度下,窄带透光抚育和均匀透光抚育效果近似,是均可采用的2种抚育方式。     

不同抚育强度下的“栽针保阔”红松林群落结构与动态

采用样带网格调查法和分层株数法,研究了不同抚育强度的"栽针保阔"红松林群落结构及动态变化趋势,定量评价了不同抚育强度对其群落结构及动态的影响。结果表明:栽针保阔红松林群落的郁闭度由大到小,重要值增大(0.300～0.708),在群落中的优势地位上升;红松中径级林木比例增加,小径级林木比例减少;各群落总体上均呈现出向红松针阔混交林进展型演替趋势,但以中、低郁闭度群落演替趋势较好。     

阔叶林不同郁闭度下人工更新红松林状况分析

阔叶林下栽植红松,在同等抚育条件下,试验区人工更新红松苗木生长量随着郁闭度的增加而降低,林分透光量越大,红松苗木生长得越好。从而得出结论,在人工更新上可以适地适树营造红松,建立阔叶林下红松更新层群落,有利于恢复小兴安岭森林顶级群落——阔叶红松林。     

不同抚育强度对人天混红松林群落演替的影响

采用样带网格调查法和分层株数法,研究了不同抚育强度下人天混红松林群落的演替趋势。结果表明：未透光群落中红松和五角槭属于进展种群,花曲柳属于潜在稳定种群,而蒙古栎属于衰退种群;半透光群落中红松、水曲柳和假色槭属于潜在进展种群,花曲柳和五角槭属于稳定种群,而蒙古栎属于衰退种群;全透光群落中红松、花曲柳、五角槭和灯台树属于潜在进展种群,裂叶榆、青楷槭和花楷槭属于潜在稳定种群,而蒙古栎属于衰退种群。不同林分均呈现出进展演替趋势,都向着红松硬阔叶混交林方向发展。     

小兴安岭阔叶红松林林分结构与修复

小兴安岭阔叶红松林（Pinus koraiensis）是地带性顶极植被.本文以黑龙江丰林国家级自然保护区阔叶红松林为研究对象,系统分析小兴安岭阔叶红松林林分类型分布的斑块和年龄特征、垂直分布特征,论证郁闭度对红松群落数量、幼林生长群落的影响,阐述不同林分类型对红松天然更新的影响、上层林冠抚育对红松幼树的影响、上层林冠抚育强度对红松生长的影响.结果证明：透光抚育为红松提供了良好的生长空间,上层抚育可显著提高林冠下红松幼树的高生长、地径生长和保存率,提出了小兴安岭阔叶红松林生态修复的策略.     

基于“近自然林业”的红松林主要树种重要值的研究

以“近自然林业”为指导思想,对凉水自然保护区不同类型红松林主要树种的重要值进行了研究。结果表明：红松在天然林内并不占据优势地位;红松人工纯林内红松的重要值都很大,都大于同林分内的阔叶树主要树种的重要值之和;林隙透光抚育林内红松的重要值为107．98％,而其他几个阔叶树种色木、白桦、椴树和杨树的重要值相加为121．69％,主要树种中针叶树种和阔叶树种的比值接近1∶1,这种重要值的比率使整个林分的针阔比处于一种平衡的状态。     

Effect of thinning intensity on tree growth and temporal variation of seed and cone production in a Pinus koraiensis plantation

Thinning of Korean pine (Pinus koraiensis Sieb. et Zucc.) is used to facilitate timber and cone production. The present study in Northeast China investigated the effects of thinning intensity on individual tree growth, temporal variation in cone yield, and seed quality in Korean pine plantation. In 2005, five thinning intensity levels (none, extreme, heavy, moderate and light) were set in 15 permanent plots in a 32-year-old Korean pine plantation at Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province. We recorded tree growth and seed cone production from 2013 to 2016, i.e., from 8 to 11 years after thinning. Except for height growth, thinning increased tree growth (diameter at breast height and crown size) and improved cone yield. The extreme thinning treatment (to 300 trees per hectare) resulted in the largest tree diameter, tree volume, crown size and 4-year cone production per tree. The highest cone yield per tree in the mast year (2014) was observed when stands were thinned to 500 trees per hectare (heavy thinning). Although the best cone and seed quality and the largest cone and seed mass per tree were recorded in the heavily thinned stand, no significant differences were found between heavy and moderate thinning stands (750 trees per hectare). At the stand level, the moderately thinned stand had the highest basal area, stock volume and seed cone production per stand. Our results suggest that thinning to 750 trees per hectare will improve timber and cone productivity in 40-year-old P. koraiensis stands.     

桂西南马尾松人工林生长对不同强度采伐的动态响应

[目的]研究不同强度采伐下马尾松的生长动态,筛选适宜的采伐强度,为马尾松人工林近自然经营提供技术支撑。[方法]2007年10月在14年生马尾松人工林(保存密度1 100株·hm~(-2))内进行采伐试验,设置4个采伐强度,即保留密度分别为225、300、375、450株·hm~(-2),以不采伐为对照;其后,自2008年开始连续8 a,每2 a测定1次马尾松的胸径、树高、枝下高和冠面积等生长指标,并计算单株材积和林分蓄积量,应用方差分析和Duncan多重比较分析生长指标对不同采伐强度的动态响应。[结果]表明:采伐强度显著影响林分生长,其中,林分平均胸径、单株材积、冠面积的年均增长量随保留密度增大而减小,但均显著高于对照(P0.05)。采伐后第1 3年,马尾松冠面积增长量显著高于采伐后期,胸径则在采伐后第3 5年最高,而不同采伐强度对林分树高生长影响不明显。保留密度显著影响林分枝下高和蓄积量的动态变化,其年均增长量随密度增大而递增。5个处理间林分蓄积年均增长量的差异随林龄的增大而逐渐缩小。[结论]马尾松人工林生长对不同强度采伐的动态响应以树冠最敏感,冠面积首先陡然增大,进而引起胸径的快速生长。树高和枝下高在采伐后年均增量变化相对平稳。4个采伐强度均显著促进单株材积生长,而仅保留密度为225株·hm~(-2)的采伐对林分蓄积增长量影响显著。综合比较林分的单株材积和林分蓄积连年增长量,建议在桂西南15年生马尾松人工林近自然经营中宜选择300株·hm~(-2)的保留密度进行采伐。     

粤北马尾松人工林坡向效应分析

马尾松 Pinus massoniana 是粤北主要造林树种之一,研究以韶关地区 20 a 生马尾松人工林为 研究对象,重点研究坡向对其人工林生长的影响,并探讨其可行的调整经营措施。结果表明,南坡马尾 松的胸径和树高均显著高于北坡,坡顶胸径与北坡近似,树高大于北坡,且径高比最高;北坡的冠幅、 冠长和冠体积均高于南坡和坡顶,反映马尾松喜光特性。南坡单株材积高于北坡和坡顶,坡顶中小径级 个体 (DBH 10~25 cm) 比例高于南坡和北坡,但大径级个体 (DBH 25~30 cm) 比例明显下降,大径级个体 单株材积和比例对林分蓄积影响最大,蓄积以南坡最高,其次为北坡,坡顶最低。根据不同径级单株材 积和蓄积的坡向间差异及形成原因分析,探讨了不同坡向马尾松间伐强度、改造树种选择和培育模式, 对于促进马尾松人工纯林的林分改造和森林质量精准提升具有指导作用。     

Comparative analysis on the litter in Korean pine Mongolian scots pine and dahurian larch plantations (I) Amount and fluctuation of litter fall

Investigations were made in korean pine, mongolian scots pine and dahurian larch plantations in Laoshan Plantation Experiment Station of Maoershan Experiment Forest Farm of Northeast Forestry University. Data are tabulated on the amount and seasonal and annual fluctuations of fractional composition of the litter (conifer needles, branches, cones, bark scales, broad leaves) in the three plantations. The accounts of conifer needle branch and bark scale litter are as follows: korean pine: 71.16%, 6.23% and 7.32%; mongolian scots pine: 43.65%, 18.52 % and 32.12%; dahurian larch: 90.30%, 7.83% and 1.85%. There are certain broadleaf litter in dahurian larch and mongolian scots pine plantations (account for 7.61% and 8.92% respectively). The litter wither and fall concent ratively in autumn in dahurian larch plantation and scattered all year long in korean pine and mongolian scots pine plantations. Along with the increase of stand age, the absolute amount of litter tend to increase, the relative amount of main fractional compositions (conifer needle, branch and bark scale) in korean pine and mongolian Scots pine plantations maintain stead, whereas in dahurian larch plantation, the relative amount of conifer needle is decreased gradually and the relative amount of other fractional compositions are increased gradually.     

The effect of quality bucking and automatic bucking on harvesting productivity and product recovery in a pine-dominated stand

On-board computers (OBC) of harvesting machines can now provide optimized bucking (task of cutting stems into different log lengths) by relying on value and demand matrices. Despite existing benefits of these systems in certain countries, they remain largely underutilized and generally poorly understood in German mechanized forest operations. The study aimed to compare and quantify the differences in harvesting productivity and value recovery between two treatments: quality bucking (OFF) and automatic bucking (ON). A mature forest stand with a high proportion of Scots pine (Pinus sylvestris L.) was divided into plots (30 m × 100 m) where initial tests of both treatments were randomly distributed and replicated 10 times for a total of 11 plots per treatment. Pre-harvest inventory was performed on each tree targeted for removal via a commercial thinning silvicultural treatment. Mechanized harvesting was performed with an excavator-based Atlas Kern T23 Königstiger single-grip harvester. The same assortment specifications and prices were used for both treatments but on-board optimized bucking solutions were applied in the ON plots, whereas the operator had full control of the products to be recovered in the OFF plots. During harvesting operations, continuous time and motion was performed in all plots. Average harvesting productivity was higher—but not statistically significant—in OFF plots compared to ON plots by 2.0 and 0.46 m³/PMH₀ for pine and spruce trees, respectively. Even if there was no difference detected in volume recovery for both treatments and tree species, value recovery was more than 1.60 € per cubic meter higher for pine in larger diameter classes when using quality bucking. This may be due to the fact that the algorithm of the OBC is designed for pine trees with a simpler crown architecture than trees harvested in this study. Results supporting quality bucking over automatic bucking in a Scots pine-dominated stands provide important forest operational information to managers.

     

COMPARATIVE ANALYSIS ON THE LITTER IN KOREAN PINE MONGOLIAN SCOTS PINE AND DAHURIAN LARCH PLANTATIONS(Ⅰ) AMOUNT AND FLUCTUATION OF LITTER FALL

Koreanpine(Pinuskoraiensis)(KP),mongolianscotspine(Pinussylvestrisvarmongolica)(MSP)anddahurianlarch(LarisgmeIinii)(DL)arethemainconiferousspeciesforforestationinnortheastregionofChina-LargeareplantationsofKP,MSPandDLhavebeenplantedintheregionsincel95o's.Whetherthestandstabilityandecolo-gicalequilibriumcanbemaintainedandtheforestfloorproductivitycanincreaseintheplantati0nsismainlydeterminedbytheamount,fracti0nalandchemicalcomp0sitionanddecomp0sitionrateof1itters,exceptforinfluenceofl0ca…     

红松人工林不同间伐强度对降雨再分配的影响

为研究间伐对红松人工林水源涵养功能的影响程度,该文以本溪县草河口地区70 年生不同间伐强度(对照区、中度区、极强区)的红松人工林为研究对象,研究不同间伐强度对红松人工林树干径流、穿透雨及林冠截留的影响,结果表明:红松人工林的穿透雨、树干径流以及林冠截留都会随降雨强度增加而增加,穿透雨量随间伐强度增加而增加,不同间伐强度的穿透雨率差异显著(p<0.05),树干径流率差异不显著。林冠截留量随间伐强度增加而减小,且不同间伐强度的林冠截留率差异显著(p<0.05)。     

Effects of Mechanized Thinning and Prescription Fire on Stand Structure,Live Crown,and Mortality in Jeffrey Pine

ABSTRACT

Forest thinning, using cut-to-length and whole-tree harvesting systems with subsequent underburning were assessed for their influence on stand structure, health, and fire resilience in uneven-aged Jeffrey pine (Pinus jeffreyi Grev. & Balf). Stand attributes, derived from measuring trees ≥ 10.2 cm diameter at breast height (DBH), were collected from permanent plots. Trees were divided into three size classes that generally corresponded to dominant/codominant, intermediate, and suppressed crown classes. Comparisons of post- to pre-burning mortality revealed significant thinning and fire main treatment effects as well as significant interaction between these two treatments in the two larger size classes. Mortality increased by 250% in the intermediate crown class within the burned stand portion of the whole-tree treatment, whereas among dominant/codominant trees mortality rose by 160% in the burned cut-to-length treatment combination. Pre- to post-burning shifts in live crown, expressed as a percentage of total tree height, were significantly influenced by both thinning and fire main treatments in the two larger size classes, while the interaction of these treatments was also significant among the largest trees. Within both of these size classes, decreases in live crown percentage were greatest in the burned portion of the unthinned treatment, where intermediate crown class trees lost over 20% of their crowns, while reductions in dominant/codominant trees averaged nearly 25%. The second highest losses for both size classes occurred within the burned cut-to-length treatment. In the smallest trees, mortality rose sharply and live crown decreased substantially after burning in both thinning treatments and in the unthinned control. Within the two larger size classes, preburn live crown size was negatively correlated with changes in crown size subsequent to underburning while DBH was negatively correlated with postburning changes in mortality, but only in intermediate crown class trees. These results present land managers with outcomes of differing management practices presently being evaluated for their potential to enhance forest health and reduce wildfire risk in the Sierra Nevada and similar dry forest regions.     

STUDY ON RELATIONSHIPS AMONG SEEDLING QUALITY AND SURVIVAL RATE, STOCKING PERCENTAGE AND GROWTH

Seedlingqualityisoneofthemostimportantfactorsinfluencingonthesurvivalrateandstockingpercentageinafforestationespecially,thequalityofseedlingmakesgreateffectsonthegroWthofdiameterandheightdirectlyincultivatinghighyieldandfastgrowthplantation.korqanpine,mongolianscotspine,dahurianlarch,koreanspruce,manchurianash,anurcorktreeandanurlindenaremainbroadleafandconiferousspeciesforwoodinNortheastofChina.Thisisbecausethatthesespeciesnotonlyhavegoodtimberqualityandfastgrowth,butalsohavehighereconomicva…