南京郊区典型人工林分空间结构及间伐响应

采用混交度、大小比数、角尺度等林分空间分布格局参数分析了南京市郊区3种不同人工林的空间结构特征。结果表明,马尾松与杉木的混交林分平均混交度达0.61,接近较强度混交,群落的组成较复杂。而间伐前杉木林和麻栎林的混交度较小,分别为混交度为0.25和0.15,处于较弱度混交以下,群落组成较简单。马尾松与杉木混交林和麻栎林混交的平均角尺度分别为0.50和0.49,处于随机分布状态,而间伐前杉木林的林分平均角尺度为0.55,林内所有树种均属于聚集分布状态。马尾松与杉木混交林、麻栎林和间伐前杉木林的平均大小比数分别为0.61,0.5和0.54。在麻栎林中,麻栎的生长占较优势状态;在间伐前杉木林和马尾松与杉木混交林中,马尾松生长占绝对优势。杉木林间伐2 a后,林分的平均混交度由0.25上升到0.38,达到了较弱度混交以上,而林分的平均角尺度和平均大小比数变化不明显。     

杉阔混交人工林林分空间结构分析

选择以杉木和木荷为优势树种的中亚热带人工林为研究对象,结合树种组成Ⅰ和Ⅱ,利用混交度、大小比数和角尺度3种结构参数,分析了杉阔混交人工林林分空间结构.结果表明:优势树种杉木和木荷以弱度混交和中度混交为主,林分平均混交度分别为0.45和0.52,树种空间配置较简单,林分树种混交程度较低;杉木、木荷和苦槠大小比数分布比较均匀,平均大小比数在0.5左右;其余树种大小分化明显,平均大小比数在0～0.88之间,既有占优势的树种(泡桐、马尾松和丝栗栲),也有受压的树种(柯木、漆树、枫香、青冈和虎皮楠),林分平均大小比数分别为0.50和0.52,处于中庸生长状态,乔木层树种不稳定;在角尺度研究中,相对空间结构单元而言,林木水平分布存在波动性变化,分布格局呈聚集分布,平均角尺度分别为0.549 9和0.536 4.这些林分空间结构信息可为指导杉阔混交人工林合理择伐经营提供科学依据,通过合理择伐经营进行林分结构调整,提高林分质量,优化林分空间结构,以便更好地发挥其功能.     

四川盆周山地5种典型林分的空间结构对比分析

【目的】研究四川盆周山地5种典型林分空间结构的特征,为该地区森林结构化经营提供理论依据。【方法】以四川盆周山地同龄的杉木纯林、柳杉纯林、杉木-柳杉混交林及同一时期形成的人天混交林和天然次生林为研究对象,采用角尺度、混交度、大小比数和林分空间结构指数对其空间结构进行分析。【结果】1)杉木纯林、杉木-柳杉混交林、人工天然混交林和天然次生林的水平分布格局为随机分布,平均角尺度分别为0.485、0.478、0.478、0.481,柳杉纯林为均匀分布,平均角尺度为0.455。2)5种林分的大小比数频率分布比较均匀,平均大小比数分别为0.465、0.529、0.446、0.810和0.534,林分整体为中庸生长状态。3)在混交度研究中,杉木纯林和柳杉纯林以零度混交为主,平均混交度分别为0.227和0.020;杉木-柳杉混交林的平均混交度为0.460,林分整体为中度混交;人工天然混交林和天然次生林平均混交度为0.610和0.674,为强度混交。4)引入林分空间结构指数FSSI,综合分析3种林分空间结构参数,FSSI大小排序为:天然次生林>人工天然混交林>杉木-柳杉混交林>杉木纯林>柳杉纯林,其排序与林分混交度排序结果一致。【结论】该地区5种典型林分空间结构的大小比数和角尺度相差不大,林分空间结构主要受混交度的影响。     

河北省北沟林场针阔混交林空间结构优化技术研究

为了研究针阔混交林空间结构特征,用林分直径分布特征以及空间结构3个参数(角尺度、混交比和大小比数)对河北省北沟林场的华北落叶松、白桦混交林进行了分析。结果表明:该林分直径分布中,白桦的直径分布均匀,落叶松较差;林分平均角尺度为0.352 6,林分基本处于均匀分布状态;林分平均混交度为0.425,处于中度混交;从大小比数来看,林分中白桦处于优势地位,更新树种五角枫被压严重。以林分空间结构3个参数为依据,提出林分结构调整的几种方法,使林分结构更加接近最优状态。     

叶山林场常绿阔叶混交林林分空间结构研究

结合试验地调查以及林分内树种组成,利用混交度(M)、大小比数(U)和角尺度(W)3个林分结构参数,分析了叶山林场常绿阔叶混交林林分空间结构。结果表明:该林分平均混交度为0.371 8,主要树种麻栎多呈单种聚集,其余树种中强度混交比例达到96%;平均大小比数为0.493 6,在林分空间配置上,马尾松处于优势状态,其余树种分化严重;平均角尺度为0.518 9,混交林的分布格局基本上以团状分布为主。     

小陇山辽东栎次生林的结构特征和物种多样性

运用混交度、角尺度、大小比数、林层数等林分空间结构参数,直径分布和物种多样性等非空间结构参数,对小陇山林区辽东栎天然林林分结构特征进行分析研究。结果表明:小陇山林区辽东栎天然林群落的灌木层和草本层物种丰富,多样性高;乔木层物种多样性指数明显低于灌木层和草本层;直径分布特征表现为典型的异龄林直径分布特征;林分天然更新良好,辽东栎实生苗占幼苗总数的46%;林分中林木个体分布角尺度均值为0.541,林木个体水平分布格局属团状分布;群落的树种隔离程度较高,平均混交度高达0.71,群落中77.4%以上的林木处于中度混交以上,处于强度混交的比例也接近于24%;林分中各树种以胸径作为比较指标的大小比数排序为:锐齿栎辽东栎漆树灯台树华山松青榨槭三桠乌药椴树秦岭白蜡梾木;在垂直结构方面,林分的平均林层数为2.45层,林层分化明显。依据辽东栎林分的天然更新和结构特征提出经营建议。     

柏木、马褂木和杉木等针阔混交林结构化森林经营研究

以29a生柏木、马褂木和杉木针阔混交林为研究材料,利用结构化森林经营技术评价林分的稳定性。结果表明:柏木、马褂木和杉木等针阔混交林中树种优势程度最高的为柏木,其次为马褂木;整个林分中的树种为随机分布,林分中林木大多数处于强度混交和极强度混交的状态,其中刺槐、翅荚木、构树和马尾松平均混交度为1,为极强度混交。女贞、黄檀、蓝果树、香椿、和油桐为强度混交。优势树种柏木、马褂木和杉木中,马褂木的平均混交度0.615,处于中度混交状态,杉木的平均混交度0.519,处于中度混交状态,柏木的平均混交度为0.484,处于弱度混交与中度混交之间。林分中翅荚木和构树的平均大小比数为1,在它们所处的结构单元中处于绝对劣势状态;黄檀、蓝果树和油桐的平均大小比数在0.750~0.856之间,处于劣势状态;刺槐和杉木的平均大小比数在0.5~0.618之间,处于从劣势向中庸过渡状态;柏木、女贞、马褂木、马尾松、黄樟和香椿平均大小比数在0.25~0.5之间,处于从中庸向亚优势过渡状态;林分中,天然更新情况均达到了更新良好的等级,林分处于健康稳定的状态,目前不需要经营。结果为柏木、马褂木和杉木针阔混交林经营提供了理论依据和技术支持。     

清原县蒙古栎天然次生混交林空间结构分析

以抚顺市清原县蒙古栎天然次生林为研究对象,采用混交度、角尺度和胸径大小比数3个空间结构参数分析了林分的空间结构。结果表明:林分的平均混交度为0.572,属于中度混交;林分的平均角尺度为0.494,属于随机分布;林分的平均胸径大小比数为0.499,林分处于中庸状态,不同径级林木分布较为均匀。整个林分的混交状况较好,种群隔离程度较高,林分相对稳定。     

大兴安岭林区典型阔叶混交林林分空间结构特征

文章以大兴安岭阔叶混交林为研究对象,利用角尺度、混交度和大小比数3种林分空间结构参数,研究了阔叶混交林的空间结构。研究发现：林分中随着径级的增加,林木株数呈逐渐减少的趋势;林分的平均角尺度为0.526,林分整体空间格局偏向于聚集分布状态;林分平均混交度为0.436,林分处于中弱度混交;林分的大小比数平均值为0.455,林分内各树种整体上处于中庸状态。     

川西山地岷江冷杉风景林林分空间结构分析

应用传统林分结构因子配合混交度、角尺度、大小比数和开敞度4个林分空间结构参数,分析了川西山地退化风景林的空间结构特征.结果表明:林分结构较为简单,林分乔木层由7个树种组成,树种密度分布差异较大,树种结构相对单一;林分垂直结构特征明显,可分为3个林层,呈现出典型的复层林结构特征;林分平均混交度为0.46,以中强度混交单元为主,所占比例达61％;平均角尺度为0.483,属于随机分布状态;林木的胸径大小比数为0.286,有接近30％的林木处于优势状态;林分平均敞开度为0.309,林木生长空间基本充足.岷江冷杉种群优势度明显,群落处于相对稳定状态,其他5个树种由于株数较少,且径级分布不连续,自然更新较困难,经过一定时间的演化,将死亡,因此必须切实采取保护措施,保证其顺利生长,以保持物种多样性和群落的稳定性.     

STUDIES ON STRUCTURE AND FUNCTIONS OF MONGOLIAN OAK FORESTS

INTRODUCTIoNMongoIianoak(QItcI.cIISn1ongolica)extcnsi\'cl)'dlstributcsinDaxing-anli11g-Xiaoxing-anllng,Wandasl1an-Zl1angguangcail-ing.andl11oUI1tai11ousrcgiol1sofSl1a11jial1gPlainonhorizonIalscalca11d35I)-6()l)111abo`.cscalcvcIonaItitudcscalc.Itisoncof111ainaccol11pan}4ngtrccsPCcicsintl1czo11alforcsttypesinHcilonaiia11gProtincc.Thcstandsdominatcdb}'MongolianoakoccuP}'tIlcIarg-cstarcaintl1enaturaIsccondary'forcstrcgionsthatoriginalcdaftcrtl1cdcstructionof\'irgil1forcsts.Mongolia…     

Effects of fuel reduction on birds in pitch pine-scrub oak barrens of the United States

Fire-dependent ecosystems include some of the most threatened ecosystems in the world, and where fuels are allowed to accumulate, they can present significant threats to human life and property. Fuel reduction activities can be effective in reducing the risk of wildfire, but these practices need to be evaluated relative to their effect on biodiversity. We surveyed birds in an inland pitch pine-scrub oak barren, a fire-dependent plant community, in which fuel reduction had been carried out via thinning of canopy trees to reduce the risk of running crown fires. We hypothesized that thinning pitch pine forest would negatively affect the abundance of mature forest birds and positively affect the abundance of scrub-shrub birds. Our results confirmed these expectations: several mature forest bird species were less abundant in thinned pitch pine than unthinned pitch pine, although most of these species were also present in mixed deciduous forest, and therefore regionally well represented. In contrast, another group of bird species was scarce or absent from unthinned pitch pine and mixed deciduous forest, but present in thinned sites and scrub oak stands. These were scrub-shrub species that do not nest in mixed deciduous or pitch pine forest but depend on shrubland or savannah habitats that cover ∼3% of the region. We conclude that fuel reduction by thinning canopy trees at this site provides habitat for high-priority scrub-shrub bird species at the cost of modest reductions in numbers of forest birds whose regional aggregate population is large.     

THE WAY OF RESTORING AND REESTABLISHING BROADLEAVED/CONIFEROUS MIXED FOREST ECOSYSTEM FROM SECONDARY FOREST OF MONGOLIAN OAK

The necessity,basis,characteristic and methods of restoring and reestabling broadleaved/coniferous mixed forest ecosystem from the secondary forest of Mongolian oak(Quercus mongolica)are briefly set forth;then several effective methods of restoration and reestablishment are put forward and discussed as follows:openning up effect belt or island to establish horizontal order mixture;replenishing the blank niche to make vertical orderly mix-ture;planting artificial mixed forest to create biological diversity;developing ecological forestry,establishing integrated agroforestry ecosystem;and closing the land for forest and pre-serving some stands considering special conditions and demads.     

Fire-driven oak regeneration in French Mediterranean ecosystems

Regeneration by seeds for cork oak (Quercus suber) and companion oaks (holm oak Quercus ilex and downy oak Quercus pubescens) is likely to be poor in the fire-prone Maures massif (southern France) but the causes are poorly known. Our objective was to assess the effective recruitment for these three oak species and their temporal pattern of recruitment, in order to determine the main limitation factors and the regeneration window of each species. We studied oak recruits (height <3 m) in naturally regenerated populations according to a gradient of fire recurrence and in five main vegetation types including shrublands and mixed mature woodlands. Fire recurrence was the main explanatory factor of oak recruitment, either directly or through vegetation type and microsite characteristics. The results indicate nil to low recruitment for holm oak and downy oak in shrublands, especially those recurrently burned and dominated by Cistus species. Cork oak recruited better than the other oaks in medium and high shrublands dominated by Erica arborea. In contrast, recruitment was high for holm and downy oak in mixed oak stands and mixed pine-oak stands that have not burned for decades. Microsite conditions such as coverage by litter and shrubs influenced oak recruitment, whereas landscape configuration and stand basal area had no influence. Our results suggest that strategic shrub-clearing, oak planting and protection of mixed oak woodlands as seed sources would help maintaining oak populations in the woodland–shrubland mosaic.     

A quantitative approach to cork oak forest management

Mathematical programming is one quantitative technique that can be used for strategic and tactical natural resources planning. It has been extensively used both at private and public forest planning levels. Nevertheless, most applications concentrate on modelling of systems involving timber harvesting. This paper focuses on cork oak (Quercus suber L.) forest management. It summarizes the methodology to follow in order to generate information needed for modelling purposes. It formulates a cork oak forest management problem using a linear programming model. A case study is used to illustrate the procedure used. The results of the research on a modelling approach to cork oak forest management for an area extending over 5272 ha in the Portuguese submediterranean ecological region are presented. Extensions to this study are identified.     

松栎混交林的形成及其生态功能研究

确立了油松、辽东栎混交的三种优化模式，对松栎混交林的生态防护功能作了详细分析，充分证明了松、栎混交林结构的稳定性及其巨大的生态防护效益。该文还就大力发展松栎混交林提出合理化建议。     

Spatial structure and dynamics of predominant populations in a virgin old-growth oak forest in the Qinling Mountains,China

This paper attempts to explore the characteristics of the spatial structure and development dynamics of three predominant tree populations, Quercus aliena var. acutiserrata Maxim.(QA), Acer caesium subsp. giraldii (Pax) E. Murr.(AC), and Ulmus propinqua Koidz (U. japonica) Sag (UG), in a virgin old-growth oak broad-leaved mixed forest in the Qinling Mountains, China. We employed a bivariate distribution of the structural parameters (mingling, dominance, and uniform angle index) based on the relationship between nearest neighbor tree groups and found that all predominant populations with a high species mixture and random distribution pattern. However, QA and UG are recessional populations, and AC is a progressive population. Predominant populations showed a consistent tendency during stand development that the spatial structures became increasingly mixed; the distribution pattern gradually transformed from clumped to random, and the segregation among the tree species increased. This finding demonstrates that the populations are forming a steady-state forest structure. The QA population will continue to maintain its predominance in the forest in the future, and AC will survive and grow as an associated species over the long term. However, UG will decline, and the forest will ultimately become an oak-dominated climax forest community if there are no large-scale disturbances.     

我国栓皮栎分布及其生态学研究

栓皮栎作为广泛分布的树种之一,在全球气候变化的大环境下,成为研究树木生长应对气候变化的重要树种。文中分析了我国栓皮栎水平分布和垂直分布的特点及其与气候的关系,栓皮栎在不同地区的森林类型,主要包括栓皮栎纯林、松栎混交林、栎类混交林等类型;综述了我国对栓皮栎生态学、群落结构、更新等研究的最新进展和主要结论;提出今后开展栓皮栎研究的重点和方向,以期为栓皮栎生理生态学及其对气候变化响应研究提供参考。     

依兰国营林场不同林分结构内柞树生长状况差异及技术对策的研究

通过"样方标准地调查法"研究了依兰国营林场不同林分结构内柞树的生长状况,通过方差分析和多重比较方法得到柞树在针阔混交林、阔叶混交林和柞树纯林中的生长状况排序。结果表明:针阔混交林内柞树的胸径年均生长量、树高年均生长量和材积年均生长量3项指标在18~42 a之间均明显高于阔叶混交林内柞树和柞树纯林,优势明显。所以,无论从生态角度还是用材角度,培育混交异龄复层林结构对森林的永续经营和利用具有重要的作用。     

Grazing effects on the sustainability of an oak coppice forest

In Greece, deciduous oak forests usually provide both, wood production and grazing of understory vegetation. Grazing as a management tool was assayed in a deciduous oak coppice forest of 2000 ha under conversion during the management period of 1991–2005 in Central Macedonia, Greece. In this forest, 1340 cows and 3880 goats were grazing from May to October along the years. The impact of grazing pressure on forest growth was related to the difference of the overall wood stock in two sampling times conducted during the management period of 1991 and 2005. Three grazing pressures were distinguished in the forest: heavy, moderate and light. The moderate grazing improved tree growth and provided significant wood production during the management period. It has also resulted in a sustainable production of herbage and browse in the understory, supporting the maintenance of the livestock. It seems that the conversion of a deciduous oak coppice forest to a high forest along with livestock grazing in the understory is a very efficient management scheme for sustainable production in such a forest.