Seasonal Dynamics of Energy Return Through Litterfall of A Mixed Forest of Chinese Fir and T. odorum

Based on the measurement of monthly litterfall and their gross calor ic values, the seasonal dynamics of energy return through litterfall were determ ined in a pure and a mixed T. odorum (Tsoongiodendron odorum Chun) forests with Ch inese fir (Cunninghamia lanceolata (Lamb.) Hook.) in Sanming, Fujian Provinc e. Annual ene rgy return through litterfall was estimated as 12.648×10 6J·m -2 for the mixed fo rest, being 4 2% higher than that of the pure forest, and a large proportion of the energy return comprised leaf litter. The conversion efficiency of solar rad i ation energy into litterfall was 0 56% for mixed forest and 0 54% for pure for es t, respectively. The monthly energy flux in litterfall of Chinese fir showed a t hree-apex curve, peaked in March, August and December, respectively, which was s imilar to that in various fractions of leaf, twig, flower and fruit litter. The consistency in monthly patterns among different litter fractions of Chinese fir was attributed to their solid connections all the while. The monthly energy flux in litterfall of T. odorum culminated in January, May and August, the same was true for its leaf and twig litter. However, energy flux in flower litter only oc curred during March to May and that in fruit litter appeared in January and Marc h. The monthly dynamics of energy flux through litterfall of the two forests wer e both determined by their respective litterfall pattern of Chinese fir. Seasona l energy flux in litterfall for both mixed and pure forests followed the sequenc e of spring>winter>summer>autumn, but fluctuations in the former were less disti nct than those in the latter.

Effect of Mixed Forests of Chinese Fir and Tsoong's Tree on Soil Properties

An investigation and on 13 year old (1984～1996) Chinese fir and Tsoong's tree mixed forests in Jianou City, Fujian Province, China was carried out to compare the influences of different interplanting types of individual tree tree, row row, row strip (three rows) and pure Chinese fir stands on soil properties. Compared with the pure stands of Chinese fir, the mixed stands exerted a positive effect on soil fertility, with increases in soil organic matter, total N, available P and available K. Moreover, improvements were also observed in soil enzymatic activities, aggregate structure, structure stability, status of soil porosity, soil aeration and penetrability in mixed stands. The row row interplanted stands had the best effect on tree growth and soil properties among these mixed forests. In the southern subtropical region, the spreading of the row row mixing model of the two tree species would be helpful to preventing the soil from fertility deterioration caused by successive plantation of Chinese fir.

THE COMBUSTIBILITY OF CHINESE FIR AND MACCLURE MICHELIA MIXED FOREST

Based on the theory of forest burning link, the combustibility of the 6-year-old Chinese fir (Cunninghamia lanceolata) and macclure michelia (Michelia macclurei) mixed forest was determined in Youxi County, Fujian Province from 1988 to 1989. The results show that the daily mean moisture in the forest, moisture content of litter and the water reserves of the stand in mixed forest are 3%, 7.6% and 46.8% higher than that in pure stand respectively, the inflammables quantity and energy ratios of the stand biomass and total potential energy in mixed stand are 8.5% and 3.69% lower than that in pure stand respectively. Mixed forest can decrease the combustibility of stand.

Composition and properties of soil humus in a mixed forest of Cunninghamia lanceolata and Tsoongiodendron odorum

This study was conducted in Xinkou Experimental Forestry Farm of Fujian Agricultural and Forestry University, Sanming, Fujian Province in January 1999. Taking pure stand of Chinese fir as control, the authors measured and studied the content of organic carbon, content of humic acid (HA), ratio of HA to fulvic acid (FA), and the characteristics of infrared light spectrum and visible light spectrum of soil humus in the mixed forest of Chinese fir and Tsoong?tree. Compared to humus composition in the pure stand of Chinese fir, the content of soil organic C, HA content, and the E4 value of HA for different layers of soil, except for the ratio of HA to FA, showed a significant increase in the mixed forest, while the ratios of E4 to E6 had a little decrease. The infrared light spectrum of humic acid had an absorptive peak at 1650 cm-1. It is concluded that the levels of humification and aromaticity of soil humus are higher in the mixed forest, which is favorable for the improvement of soil structure and nutrient supply, thus improving the soil fertility to a certain degree.

Dynamics of nitrogen and phosphorus concentrations of fine roots in a mixed forest of Cunninghamia lanceolata and Tsoongiodendron odorum

From September 1999 to July 2000, N and P concentrations of fine roots were measured with the method of sequential soil core at bimonthly intervals in a mixed forest of Tsoong's tree (Tsoongiodendron odorum Chun) and Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) in Sanming, Fujian. The results showed that N, P concentration of Chinese fir and Tsoong's tree in fine roots were negatively related to root diameter size. The concentrations of N and P in living roots and dead roots were compared. The order of N concentration in fine roots in different samples was Tsoong's tree>undergrowth>Chinese fir, while that of P was undergrowth>Tsoong's tree>Chinese fir. For Chinese fir, the seasonal change of N, P concentrations in fine roots with various diameter classes showed a single-apex curve with a maximum in September. For Tsoong's tree, maximized concentration of N in fine roots appeared in July or September and maximized P concentration in May.

Optimum stand density of Chinese pine forests in Taihang limestone mountains, Shanxi Province

Data analysis was made for 54 stands of Chinese pine forests for soil and water conservation and timber. The regression equations were drawn up on forest density and different rafter timber and bush coverage.Based on those equations, the number of rafter timber trees, storage, number of non-raffer timber trees, stand volume and the output value were calculated for six different forest densities ranged from 1250 to 6600 trees/hm2.According to the economic and ecological criteria, the optimum density for Chinese pine forests was determined as 1 650 trees/hm2.

南方红壤丘陵区水土保持林对枯落物和土壤养分的影响

探究不同水土保持林土壤有机碳及土壤养分变化,为水土保持林的营造提供科学依据。以湖南省金洞林场15年生杉木-闽楠混交林、闽楠纯林、杉木纯林为研究对象,测定不同季节土壤有机碳、土壤及凋落物养分含量,分析不同林分组成和季节对土壤有机碳的影响。结果表明,林分组成和季节对土壤有机碳含量存在显著影响,土壤有机碳主要受全N、全P、可溶性有机碳、可溶性有机N的影响。不同林分下,土壤养分和凋落物养分存在显著差异,杉木-闽楠混交林土壤和凋落物养分显著高于杉木纯林、闽楠纯林,其土壤有机碳、全N、全P比杉木纯林高35.07%~52.63%,凋落物矿质元素含量比闽楠纯林高25.35%~45.16%。季节因子对土壤养分的影响高于凋落物养分,季节因子对凋落物矿质元素无显著影响。林分组成对土壤有机碳的影响主要通过改变土壤理化性质,特别是N素含量来影响土壤有机碳;季节因子对土壤有机碳的影响通过改变水热条件及凋落物分解速率,从而影响土壤有机碳的输入、输出。研究结果对南方红壤地区水土保持林的营造具有一定的参考意义。

田林老山中山两类森林凋落物研究

田林老山中山两类森林凋落物研究梁宏温（广西农学院林学分院，南宁５３０００１）ＳｔｕｄｉｅｓｏｎｔｈｅＬｉｔｔｅｒｆａｌｌｏｆＴｗｏＦｏｒｅｓｔＴｙｐｃｓｉｎＭｉｄ—ＡｌｔｉｔｕｄｅｏｆＬａｏｓｈａｎＭｏｕｎｔａｉｎｉｎＴｉａｎｌｉｎＣｏｕｎｔｙ．￥Ｌ...

杉木林分密度对套种闽楠树型、光合能力及生物量分配的影响

[目的]通过探讨不同林分密度杉木林下套种闽楠的树型结构、光合作用及生物量分配的适应性变化规律,为杉木近成熟林林分质量精准改造与提升提供科学依据。[方法]选择21年生杉木人工林为研究对象,通过设置375株·hm^(-2)、570株·hm^(-2)、630株·hm^(-2)和810株·hm^(-2)等4个间伐保留密度处理,分别进行林下套种900株·hm^(-2)闽楠形成杉阔复层林,测定分析林下套种5 a后闽楠冠型、侧枝长度、分枝角、叶片形态、叶绿素荧光参数、SPAD值,以及侧枝、茎干和叶片不同器官生物量等主要适应性生长指标的差异,探讨林分密度对林下套种闽楠树冠形态特性、光合能力及生物量分配的影响规律。[结果]低林分密度(375株·hm^(-2)和570株·hm^(-2))杉木下套种的闽楠2级侧枝长、1级和2级侧枝密度大于810株·hm^(-2)林分密度处理。闽楠叶片的叶面积、比叶面积表现出随着杉木林分密度增加而增加,其中,杉木林分密度375株·hm^(-2)的叶面积、比叶面积显著小于杉木林分密度810株·hm^(-2),相差80.97 cm^(2)和10.43 cm^(2)·g-1;810株·hm^(-2)林分密度处理下,闽楠叶片的叶绿素荧光参数和SPAD值均高于375株·hm^(-2)林分密度处理。低林分密度下(375株·hm^(-2)和570株·hm^(-2))套种的闽楠下层树冠叶片、总叶片生物量、以及侧枝和茎干生物量均显著大于810株·hm^(-2)林分密度处理(p<0.05)。375株·hm^(-2)林分密度处理下,闽楠通过增加株高,促进侧枝生物量积累;810株·hm^(-2)林分密度处理下,闽楠减少对株高的投资,从而增加叶片生物量的积累。[结论]在低林分密度(375株·hm^(-2)和570株·hm^(-2))下,林下光照充足有利于闽楠生物量积累,侧枝生长,其生长状况较好;在高林分密度下(630株·hm^(-2)和810株·hm^(-2)),闽楠可通过促使叶片长度变长,增大叶片比叶面积,增加叶片SPAD值,提高光合电子传递速率和光能捕获效率等变化来增强光捕获能力,从而适应光照资源不足的生存环境。

间伐对杉木林枯落物和土壤水源涵养能力的动态变化分析

探讨不同间伐年限对杉木林枯落物层和土壤层持水能力的影响,为评估杉木林水源涵养功能对间伐的响应提供科学依据。以浙西南景宁县间伐1年、间伐3年、间伐8年和未间伐的杉木林为对象,采集枯落物与土壤样品,分析测定枯落物含水率、持水能力、土壤容重、非毛孔隙度并计算相关指标。结果表明:杉木林枯落物现存量在不同间伐年限间的差异并不显著(P>0.05);枯落物持水量、持水速率与浸水时间的关系分别符合对数函数和幂函数;间伐8年的杉木林枯落物层的最大持水率、最大拦蓄率和有效拦蓄率均显著高于未间伐林分(P<0.05);间伐3年、间伐8年的杉木林枯落物最大持水量和有效拦蓄量均显著高于未间伐林分;间伐8年杉木林地0~10 cm土层土壤容重显著降低(P<0.05),非毛管孔隙度显著增大,非毛管持水量显著增加了22.4%(P<0.05),而对10~30 cm土层土壤储水性能相关指标的影响不显著(P>0.05)。综上,杉木林枯落物层和土壤层的水源涵养功能随着间伐年限的延长而增强。

阔叶混交林与杉木萌芽林的净生产力及水源涵养能力比较

[目的]分析福建省泉州市山美水库库区9年生阔叶混交林及杉木萌芽林的净生产力和水源涵养功能,为其水源涵养林的改造提供参考。[方法]设置标准样地,调查山美水库库区9年生闽粤栲×台湾相思×火力楠阔叶混交林及杉木萌芽林林分生长量、生物量及年净生产力,并测定生态系统各组分水源涵养能力。[结果]阔叶混交林乔木层生物量、年净生产力以及地上部分总生物量、最大持水量和排水能力分别比杉木萌芽林显著提高22.44%、14.73%、18.01%、18.21%和17.45%。阔叶混交林的土壤持水指标优于杉木萌芽林,其中0~40 cm土层土壤的最大持水量和排水能力分别比杉木萌芽林显著提高17.21%和19.85%。阔叶混交林林分最大持水量和排水能力分别比杉木萌芽林显著提高17.23%和19.80%。[结论]闽粤栲×台湾相思×火力楠阔叶混交林可有效提升林分净生产力和水源涵养功能,该混交模式可在水源涵养林改造提升工程中推广应用。

立地因子对半天然杉阔混交林生长的影响

为高质量培育杉木Cunninghamia lanceolata速生丰产大径材和檫树Sassafras tzumu珍贵用材,精准提升森林经营成效,以13~14 a生半天然杉阔混交林为研究对象,分析不同坡向、坡位、立地等级对其生长的影响。结果表明,3个坡向杉木胸径、树高和材积生长量表现为阴坡>半阴坡>半阳坡,不同坡向间差异极显著(P<0.01);木荷Schima superba和檫树的胸径、树高、材积生长量表现为半阳坡>半阴坡>阴坡,不同坡向间木荷生长差异不显著,檫树胸径、材积生长差异极显著(P<0.01)。3个坡位杉木、檫树的胸径、树高、材积生长量表现为下部>中部>上部,杉木胸径、树高、材积生长差异均为极显著(P<0.01);檫树胸径、树高生长差异显著(P<0.05),材积生长差异极显著(P<0.01);木荷胸径、树高、材积生长差异不显著。2个立地级杉木、木荷、檫树胸径、树高和材积生长量表现为Ⅰ立地级>Ⅱ立地级,杉木树高生长差异显著(P<0.05),胸径、材积生长差异极显著(P<0.01);木荷胸径、材积生长差异不显著,树高生长差异显著(P<0.05);檫树胸径、树高、材积生长差异极显著(P<0.01)。在一代杉木林阴坡、山坡下部、Ⅰ立地级条件下,连栽杉木混生天然檫树林分中,13~14 a生杉木平均树高12.4~13.9 m、平均胸径14.0~14.8 cm、蓄积量201.45~248.90 m^(3)·hm^(-2)、年均蓄积生长量15.50~19.15 m^(3)·hm^(-2),达到速生丰产林大径材指标。

火力楠杉木混交林抚育技术应用研究

火力楠杉木混交林是南方地区重要的人工林,在生态建设中发挥着重要作用.本文从混交林的生态特性出发,对优化混交比例与配置模式,土壤管理与营养调控,病虫害防治以及抚育措施等关键技术进行了探讨了,并案例分析,证实了这些技术在改善林分结构,提升生态功能方面的显著效果.研究表明,科学的混交林抚育经营是实现生态效益与经济效益双赢的有效途径之一。

不同混交模式对杉木初期生长特征的影响

本文以檫木、香樟、枫香、乐昌含笑和火力楠5种速生阔叶树木作为杉木的混交树种,对不同混交模式下杉木的树高、地径、胸径和材积4项生长指标与杉木纯林进行对比与分析,以研究出5种混交树种中效果最佳的树种。结果表明:在经历1~2 a的适应期后,从第3 a开始,不同混交模式下杉木生长量均表现出显著性差异。其中,杉木+枫香混交模式中杉木的地径、胸径和材积生长量显著高于其余四种混交模式以及杉木纯林的生长量,说明枫香对杉木的树体生长具有明显的促进作用,杉木×枫香混交是种间关系较为协调的模式。

不同生境中杉阔混交林物种多样性特征初步研究

根据生境因子应用主分量分析和动态聚类方法进行生境的划分 ,在此基础上分析不同生境中杉阔混交林群落数量特征。结果表明 :不同生境中植物群落的主要优势种组成不一 ,其重要值也不同。不同生境中植物群落乔木层的物种数目、物种多样性、群落均匀度均有较大差异。海拔对不同生境中植物群落乔木层的物种数目、物种多样性和群落均匀度有很大影响 ,坡向则对个体总数和种类数量的影响较大。海拔和坡向对不同生境中植物群落乔木层生态优势度则无明显影响。

杉木拟赤杨混交林土壤肥力性状研究

通过对 1 1年生杉木拟赤杨混交林土壤肥力测定结果表明 :杉拟混交林土壤结构体、孔隙状况、水分状况和土壤化学性质均较杉木纯林有所改善 ;各模式 0～ 2 0cm土壤 >0 .2 5mm的水稳性团聚体含量比杉木纯林提高 6.2 1 % ;总孔隙度和通气度分别较杉木纯林增加 9.87%和 1 8.0 6% ;杉拟 3∶1混交林 0～2 0cm土层的最大持水量、毛管持水量和最小持水量比杉木纯林分别提高了 1 1 .96% ,2 0 .5 5 % ,2 2 .46% ;各模式土壤养分含量有所提高 ,杉拟 3∶1混交林土壤有机质比杉木纯林提高 43 .96%。这说明通过落叶阔叶树和常绿针叶树之间的混交具有较强的培肥土壤和水源涵养作用 ,对防止杉木多代连栽造成的地力衰退问题具有重要的指导意义。

雨雪冰冻灾害干扰对杉木人工林土壤动物的影响

2008年1月中国南方遭受了一场罕见的雨雪冰冻灾害,对基础设施、生态与环境造成了严重影响.为了分析雪灾对森林生态系统的长期影响,在以往定位观测的基础上,开展了土壤动物调查.根据湖南会同林区杉木(Cunninghamia lanceolata)纯林和杉木-桤木(Alnus cre-mastogyne)混交林在受到大规模雨雪天气干扰停止40d以后的土壤动物调查数据,并利用2007年同期的监测数据作为灾前正常水平的参照,选择土壤动物群落的2个主要参数(多度和群落组成)作为评价指标,初步评估了土壤动物对于灾害性天气干扰表现的弹性和抗性.结果表明:相对于灾前水平,灾后土壤动物发生了明显变化,微型土壤动物如线虫出现了爆发性增长,在纯林中线虫多度从2007年的12216.9ind·m-2增加到目前的118343.9ind·m-2,在混交林中线虫多度从2007年的25435.9ind·m-2增加到目前的84573.0ind·m-2;大型土壤动物的多度大幅下降,纯林和混交林分别下降27.0%和85.6%;纯林凋落层中型土壤动物多度显著下降,但纯林土壤层及混交林无显著变化.在土壤动物类群多度方面,从大到小的功能群恢复进程由慢到快,表明土壤动物类群多度可以作为评估干扰和其后恢复的一个敏感指标;在群落组成方面,利用群落排序没有检测到群落组成的明显变化,表明群落组成对于雪灾干扰有很高的抗性.

杉阔混交林杉木与其混交树种种间竞争研究

分析了杉阔混交林中杉木与 1 2个主要混交树种分别在不同资源空间 (土壤物理与化学营养 )中的种间竞争情况。结果表明 :在同一资源空间中 ,杉木与混交树种的竞争结局依树种不同而异。杉木与同一混交树种在不同资源空间中具有不同的竞争结局。建议在不同立地条件或采用不同混交树种时杉木与混交树种的混交比例应不同。

毛竹杉木混交林生产力和土壤性状研究

对杉木纯林 (1 9年生 )、毛竹纯林、6种毛竹杉木混交林 (杉木 1 9年生 )的生长状况、土壤化学性质、土壤孔隙状况、水分特性、土壤水稳性团聚体组成、土壤渗透性能经济效益等方面进行研究。结果表明 ,混交林能改善土壤的物理性质和化学性质 ,提高林地土壤肥力 ,在混交林的各种模式中 ,以杉木密度 1 350株 /hm2 的混交林对土壤肥力改良效果最佳 ,生长量较大 ,经济效益较高。毛竹杉木混交林可作为我国南方改良林地土壤肥力、防止杉木多代连栽引起地力衰退的有效生物措施之一 ,能充分发挥地力、提高林地利用率。

中亚热带几种典型森林生态系统碳、氮储存功能研究

采用定位研究方法,从生态系统服务功能角度,对比研究了中亚热带区域7种典型森林生态系统碳、氮储存功能。结果表明,次生常绿阔叶林碳、氮储存功能最强,杉阔混交林碳、氮储存功能比同林龄的杉木纯林强,而第1代杉木纯林碳、氮储存功能强于连栽杉木纯林。生态系统碳、氮储存功能空间分布基本一致,土壤层是主要部分,其次为乔木层,然后是根系,林下植被层和凋落层所占比例最小。相关分析表明,土壤碳、氮储存功能与林下植被生物量、森林凋落物现存量之间都具有良好的线性关系,但与地下部分生物量相关性不明显。