孟加拉羯布罗香(Dipterocarpus turbinatus Gaertn.F)外生侵染菌根的水平分布(英文)

本文论述了孟加拉国吉大港大学校园里,不同年龄(5、10、20年)的羯布罗香(DipterocarpusturbinatusGaertn.F)人工林内,距树木基部不同距离(1、2、3、4米)处,外生侵染菌根的水平分布状况。在山的3个部位(顶部、中部和下部)对各人工林外生侵染菌根的侵染进行了测定。在不同水平分布距离处的树下采集了1000cm3的根际土壤样本,不同距离和山高处的外生侵染菌根浸染率差异显著。在5年和10年林龄的人工林内,浸染率随着距树的距离的增加而快速下降,而在20年林龄的人工林内,浸染率随着距树基部距离的增加而急剧增加。山下部20年生人工林内距树4m处的浸染率最高(81.3%),山顶部5年生人工林内距树4m处的浸染率最低(55.33%)。     

黄土高原不同树龄刺槐丛枝菌根与根际微生物的群落多样性

采用BIOLOG检测法,研究丛枝菌根与黄土高原不同树龄刺槐人工林及次生林根际微生物群落多样性的关系.结果表明:8、15、23和30年刺槐人工林随着树龄的增加,菌根侵染率先增加后降低,微生物活性(AWCD值)增大,碳源代谢丰富度指数(S)和Shannon指数(H)逐渐增加,23年达到峰值后趋于稳定,并逐渐降低,不同林地菌根侵染率与根瘤数呈显著正相关(Y=414.82 x-188.73,r=0.927,P＜0.05).主成分分析表明:刺槐人工林根际微生物群落结构与功能随着树龄的增加存在时间上的连续性,次生林优于相同树龄人工林,在碳源利用上表现为与树龄更长的人工林相近.菌根侵染率与根瘤数、细菌量、丰富度指数(S)和Shannon指数(H)的相关性分析表明:丛枝菌根对刺槐根际微生物群落的稳定和功能多样性的增加具有促进作用,在造林年限上表现为对较短树龄刺槐林根际微生物群落影响较大,在造林措施上对刺槐次生林微生物群落多样性的作用优于人工林.     

西澳州桉树林地土壤菌根菌剂接种潜力研究(英文)

对澳大利亚西澳州桉树人工林菌根类型及其形成情况进行了调查 ,并采用生物测定法 (Bioas saymeasurement)研究了桉树林地土壤菌根菌剂的接种潜力 .根系菌根检查和生物测定法试验均表明 ,在自然条件下桉树可以和不同真菌共生而形成三种类型的菌根 ,即外生菌根、VA菌根和混合菌根 ;林分成熟程度与菌根形成有一定的相关性 ,与共生体的类型也有一定影响 .在幼林中 ,桉树根系主要与内囊霉菌共生形成VA菌根 ,而成熟林主要与担子菌共生形成外生菌根 ,混合菌根表现为一种中间类型 .在收集的林地土壤中移植的菌根诱饵植物 (三叶草和蓝桉 )分别检测出土壤中存在有一定量的VA菌根菌和外生菌根菌 ,但菌根菌繁殖体数量及接种潜力相对较小 ,并且也揭示了按树年龄对土壤菌剂的相对接种潜力影响较大 .本文对桉树人工林土壤菌剂接种潜力进行了评价 ,并就引进优良菌根菌对桉树人工林生产的重要性进行讨论     

外生菌根真菌促进油松人工幼林生长试验

应用从不同林型下分离获得的外生菌根真菌纯培养菌株中的优良菌种,对油松人工林进行菌剂混合接种试验。结果表明:采用外生菌根真菌对油松林接菌,能使土壤微生物种群数量发生变化;接菌后的土壤中的细菌、真菌、放线菌总数比对照有明显的增加,其中真菌增加558.7%。接菌后的油松菌根侵染率为75%,对照为20%;采用外生菌根真菌对油松林接菌,能够提高其抗病力,增强抗旱性,促进林木的生长。对连续2年接种菌剂的油松幼林调查表明,施用菌剂的油松与对照相比,其地径、树高均有显著增加,树高增长46.1%,地径增长41.3%。所以说外生菌根真菌作为一项生物接种技术,对提高油松林的抗病力,增强抗旱性,促进林木的生长具有重要的作用。     

丛枝菌根对大青杨苗木生长的影响

利用5种丛枝菌根真菌,在不同肥态、肥力水平下对大青杨实生苗进行接种。结果表明:5种真菌都与大青杨形成了菌根,在不施肥情况下Glomusintraradices、G mosseae、G versiforme3个菌种的苗木在苗高、地径、总干生物量上都与对照表现出差异极显著,与菌根侵染率呈正相关。丛枝菌根能增加苗木对难溶性P肥的吸收和利用,特别是G sinuosa与施过磷酸钙(Ca(H2PO4)2·H2O)在有效成分(P2O5)含量0 06g·kg-1土水平下的组合对苗木有良好的促生效果,生物量积累是对照处理的3 58倍;使用G mosseae或G intraradices与施可溶性P肥磷酸氢二钾(K2HPO4),在有效成分(P2O5)含量0 03g·kg-1土水平下的组合时对苗木的促生效果达到最佳,但随着可溶性P浓度增加,丛枝菌根对苗木生物量的积累却有抑制作用;丛枝菌根同样促进苗木对硝态N和铵态N的吸收、利用,G ver -)含量0 08g·kg-1土水平下和G mosseae、siforme、G intraradices与施硝酸钾(KNO3)在有效成分(NO3 )含量0 08g·kg-1土水平下,对苗木都有良G intraradices与施硫酸铵((NH4)2SO4)在有效成分(NH4好的促生效果,总干生物量是对照处理的2 91、2 56和2 70、2 40倍;试验结果同时也表明,根际营养状况是决定菌根侵染率的重要因素之一。     

接种外生菌根真菌对马尾松幼苗生长的影响

采用松乳菇(Lactariusdeliciosus01,02)、华南牛肝菌(Suillusplacidu504)和双色蜡蘑(LaccariabicolorS238N)4株外生菌根真菌固体纯培养接种物,对马尾松进行了圃地育苗接种试验。接种6个月后取样,比较了接种和未接种马尾松幼苗的生长、菌根侵染率和氮磷钾含量的差异。结果表明,外生菌根对马尾松幼苗的生长和氮磷钾养分的吸收有明显的促进作用,接种幼苗的株高、地径、生物量和氮磷钾含量等显著增加,菌根感染率超过65%以上,较对照均达显著水平(P<0 05)。     

不同AM菌剂对石山树种任豆幼苗生长的影响

为探索任豆(Zenia insignis)接种AM菌剂后的生长效应,采用4种丛枝菌根真菌(HUN03B、XJ08A、HEB04、XJ04B)接种剂和2种接种处理方式(蘸根、穴施)接种任豆幼苗,观测其接种40、70、110和150的侵染率和侵染强度变化过程,分析接种后任豆苗木的生长及生物量动态。结果表明:4种丛枝菌根真菌对任豆苗木生长均具有一定的促进作用,接种半年后的接种苗比未接种苗的苗高增加12.29%～22.73%,地径增加24.64%～39.11%,总生物量增加37.88%～57.20%。蘸根比穴施更易使菌剂浸染任豆幼苗根系,有效提高了前期侵染率,促进苗木生长,但2种接种方式的浸染率在接种后150 d左右基本一致。任豆生长以蘸根HUN03B丛枝菌根真菌的促进作用较好。研究结果对促进石漠化地区任豆造林生长,提高石漠化地区森林植被恢复与重建有重要意义。     

多年施用氮肥对水曲柳人工林内生菌根真菌侵染及其根尖形态的影响

以水曲柳人工林1级根为研究对象,通过施氮肥处理,对不同季节和不同土壤深度根系取样,研究施用氮肥对根尖内生菌根真菌侵染率和形态与土壤N有效性、季节和土壤深度的关系.结果表明:1)施N肥处理导致水曲柳人工林1级根的菌根真菌侵染率显著降低11%,季节和土壤深度对1级根的侵染率影响显著,其中春季＞夏季＞秋季,土壤表层高于亚表层;2)施N肥导致1级根长度显著降低,季节和处理之间的交互作用影响1级根的直径和根长,季节、土层和处理3者的交互作用影响根长和比根长;3)与未侵染菌根真菌的1级根形态相比,菌根真菌侵染导致1级根平均直径未发生变化,长度略有降低,而比根长则显著减小.这种根系形态变化规律在不同处理、不同季节和不同土壤深度上表现一致.     

林龄对思茅松人工林根系生物量的影响

[目的]以云南省普洱市主要植被思茅松人工林为研究对象,探讨不同林龄思茅松人工林根系生物量的大小分布及变化特征。[方法]分别在5、8、15、25、36年生思茅松人工林内,利用内径为8.5 cm的根钻分3层(0~10、10~20、20~30 cm)获取思茅松与其它物种的细根、粗根及死根生物量数据。[结果]表明:随着思茅松人工林林龄的增长,思茅松细根生物量呈减少的趋势,而其它物种细根生物量呈增加趋势,细根生物量最大出现在36年生思茅松人工林。不同林龄思茅松人工林的思茅松粗根和死根生物量之间无显著差异,而其它物种及林分的粗根生物量和根系生物量则随林龄增长而增加。思茅松人工林的细根生物量主要分布在土壤深度0~10 cm内,其中,思茅松、其它物种、林分细根生物量以及根系生物量随土层深度的增加呈减少趋势。林龄和土壤深度对思茅松与其它物种的细根生物量有显著影响,林龄与土壤深度的交叉作用对思茅松细根生物量有显著影响,林龄对死根生物量有显著影响,林龄、土壤深度及林龄与土壤深度的交叉作用对粗根与根系的生物量有显著影响。[结论]思茅松人工林随着林龄增长,群落结构与树种组成随之发生变化,从而对根系生物量产生较大影响。     

油松心边材量及年轮数的变异特征

在太行山石灰岩区4个林龄与密度不同的油松人工林内选取40株样木,用联苯胺染色法对其上截取的350个圆盘的心、边材进行区分.在此基础上,对心、边材量及年轮数的变异进行分析.结果表明:树干4个方位的心、边材量无显著差异性(P＞0.05);边材宽度在距基部0.50～1.00 m以上到距树梢2.46～3.22 m以下相对恒定,而心材半径、心材面积与边材宽度随树高增加持续减小,横截面直径较好地解释了心、边材量的轴向变异;心、边材量的株间变异很大,胸径对此变异的解释能力高于其他树木变量;4个林分的心、边材量存在显著差异性(P＜0.05),林分尺度的心、边材量与林分生长水平及林龄的变化趋势一致;油松心材的起始形成层年龄为13年,心材年轮数随形成层年龄而增加,后者可解释前者变异的97.9%;形成层年龄为40年与60年时,心材年轮数的增长率分别为0.5年轮·a~(-1)与0.7年轮·a~(-1).研究认为用林分调查因子预测油松心、边材量及心材年轮数的变异是可行的.     

孟加拉吉大港地区丘陵森林有机物积累

在孟加拉吉大港丘陵地区,调查了热带季风气候条件下的3种人工林(7年生大叶相思(Acacia auriculiformis)林、15年生大叶相思林和18年生混交林)和1种天然林的森林凋落物及其对土壤性质的作用.结果表明,总的有机质积累随人工林树龄增加而增加,但是年积累量随之降低.在同一植被类型内,不同坡位新鲜或部分分解的凋落物有机质累计量变化较大,坡底部有机质积累量最高,沿着山坡向上逐渐减少.在15年生大叶相思人工林内,土壤整合有机物积累量变化趋势与新鲜或部分分解有机质积累量变化趋势相反.在7年生和15年生的大叶相思林以及18年龄的阔叶混交人工林内,新鲜、部分分解和完全分解(含土壤整合有机质)有机质总生产速率分别是2554.31、705.79和1028.01kg.ha-1·a-1,新鲜凋落物有机质在3种林分中的生产速率分别是38.23,19.40和30.48 kg·ha-1·a-1.3种人工林和自然林内,平均新鲜凋落物的有机质积累占有机质产出总量的32.45%,部分分解凋落物占13.50%,而全分解整合土壤有机质占54.56%.森林土壤酸度随凋落物分解阶段的深入而增加.     

The implication of using a fixed form factor in areas under different rainfall and soil conditions for Pinus kesiya in Zambia

The study was undertaken to evaluate form factors for Pinus kesiya growing in the three Zambia Forest and Forestry Industries Corporation (ZAFFICO) plantations – the Ndola, Ichimpe and Chati groups – under different rainfall (900–1 500?mm) and soil conditions (pH 4.0–5.5). Trees were sampled from the three plantation groups and 10 sample plots were established in which 10 trees were randomly sampled for cutting. Height and diameter at breast height (dbh) were the main variables that were measured and constituted the collected data. The trees were then felled and cut into segments of 0.5?m from the bottom to the top of the tree and segment diameters over bark were measured at both ends. The form factor for each tree was then calculated by dividing the sum of the volume of the tree segments by the estimated cylindrical volume of the standing tree. The results showed significant differences (p-value<0.05) in form factors among the three plantation groups. The study further showed a significant difference in form factor when the three plantation groups were compared with a fixed form factor (0.4) used by ZAFFICO plantations, indicating that the form factors are site specific. Therefore, for the benefit of customers and plantation owners, it is important that area-specific form factors should be used for each plantation group, as these groups are affected by different factors such as soils characteristics and rainfall, which have a direct effect on the form factor.     

桂西北秃杉人工林土壤肥力变化的研究

采用时空互换法,于广西南丹县山口林场选取不同林龄(9、14、20 a)的秃杉人工林作为研究对象,对其土壤物理性质、化学性质和生物化学性质(土壤酶活性)进行研究。结果表明:不同林分年龄土壤性质存在一定的差异,8、14、20 a秃杉人工林表层土壤(0 20 cm)土壤密度分别为0.978、0.914、0.890 g·cm^-3,总孔隙度分别为63.10%、65.53 %、66.40%,土壤最大持水量分别为64.55%、71.70%、74.58%。随着林龄的增长,土壤各化学和生物化学指标的变化不尽相同,但林分年龄到20年生时,多数土壤养分和酶活性指标都有所升高,土壤肥力状况得到提高。     

杉木纯林、混交林土壤微生物特性和土壤养分的比较研究

本文于2005年5月份,在中国科学院会同森林生态实验站选择了一块15年生的杉木纯林和两块15年生杉阔混交林作为研究对象,调查了林地土壤有机碳、全氮、全磷、硝态氮、有效磷和土壤微生物碳、氮、磷、基础呼吸以及呼吸熵,比较了纯林和混交林土壤微生物特性和土壤养分.结果表明,杉阔混交林的土壤有机碳、全氮、全磷硝态氮和有效磷含量高于杉木纯林;在混交林中,土壤微生物学特性得到改善.在0(10 cm和10(20 cm两层土壤中,杉阔混交林土壤微生物氮含量分别比杉木纯林高69%和61%.在0(10 cm土层,杉阔混交林土壤微生物碳、磷和基础呼吸分别比杉木纯林高11%、14%和4%;在10(20 cm土层,分别高6%、3%和3%.但是,杉阔混交林土壤微生物碳:氮比和呼吸熵较杉木纯林低34%和4%.另外,土壤微生物与土壤养分的相关性高于土壤呼吸、微生物碳:氮比和呼吸熵与土壤养分的相关性.由此可知,在针叶纯林中引入阔叶树后,土壤肥力得以改善,并有利于退化森林土壤的恢复.     

Poor Stem Form as a Potential Limitation to Private Investment in Koa Plantation Forestry in Hawaii

Providing economic incentives to landholders is an effective way of promoting sustainable forest management, conservation and restoration. In Hawaii, the main native hardwood species with commercial value is Acacia koa (koa), but lack of successful examples of koa plantation forestry hinders private investment. Financial models, which have been offered to encourage investment, assume that a particular minimum volume of merchantable wood will be harvested at rotation age. No studies have been done to determine the appropriateness of the assumed volumes for koa plantations. Three 18- to 28-year-old koa plantations were studied to determine butt-log size, crown class and crop tree potential. Estimates of present and future merchantable sawtimber volume were made for each plantation. Results indicate that most existing plantation koa trees fork so close to the ground that they will produce little to no merchantable wood. Projected sawtimber yields from crop trees in these plantations at age 45 years are 10, 15 and 90 m³/ha, which are below the 135 m³/ha yield used in the most recent financial analysis of returns on investment in koa forestry. Relaxing the crop tree criteria gives higher volume yields, but two plantations still fall short of the assumed target yield by 43 and 52%. Given such shortfalls, returns on investment will be less than predicted by the financial analysis. Nevertheless, government offered financial incentives should compensate for lower volume yields and thus promote private investment in koa plantation forestry. Insect herbivory, genetic diversity, and low stand density contribute to poor stem form of plantation koa, and research is needed to quantify the relative importance of and interactions between these factors.     

Potential of clones in improving the financial benefits of essential oil production from <Emphasis Type="Italic">Melaleuca alternifolia</Emphasis> plantations

Australian tea tree (Melaleuca alternifolia) is a woody plant that produces an essential oil with antiseptic, anti-bacterial, anti-fungal, and anti-inflammatory properties and is widely formulated into many products. Yield and financial analyses were done to compare the viability of replanting 20 ha tea tree plantations using elite clones and improved seedlings over a 15 year time frame were carried out. Four plantation options were modelled: (1) plantations established using genetically improved seedlings (ATTIA 2B) planted at a stocking of 33,333 plants/ha and (2) 16,667 plants/ha, (3) plantations established using the best three selected clones planted at a stocking of 33,333 plants/ha and (4) 16,667 plants/ha. Financial analysis showed that, at an oil price of $45/kg (as at Sep 2008), replacement plantations of either elite clones or improved seedlings are both highly profitable irrespective of the stocking employed. The Net Present Values per hectare at 7% discount rate was $45/kg (as at Sep 2008), replacement plantations of either elite clones or improved seedlings are both highly profitable irrespective of the stocking employed. The Net Present Values per hectare at 7% discount rate was 107,824, 63,640,63,640, 163,162 and 104,055 for plantation options 1, 2, 3 and 4, respectively. Plantation option 3 was predicted to give the greatest profit at any of the oil prices tested, followed by plantation option 1, 4 and 2. The break-even prices for tea tree oil production, using the production parameters in this model were104,055 for plantation options 1, 2, 3 and 4, respectively. Plantation option 3 was predicted to give the greatest profit at any of the oil prices tested, followed by plantation option 1, 4 and 2. The break-even prices for tea tree oil production, using the production parameters in this model were 11.81/kg, 15.19/kg,15.19/kg, 10.72/kg and $12.96/kg for plantation options 1, 2, 3 and 4 respectively.     

Predicting the productivity of a young hybrid poplar clone under intensive plantation management in northern Alberta,Canada using soil and site characteristics

Site productivity of the hybrid poplar clone Brooks6 was predicted using soil and site information from 6, 4-year-old plantations in north-east Alberta. Predictions were made at both the local and microsite scales. Percent sand (R ² = 0.352, P = 0.001) was the best single predictor of hybrid poplar productivity, showing a curved relationship. Soil pH also showed a curved but weaker relationship with hybrid poplar productivity (R ² = 0.133, P = 0.100). Maximum tree productivity occurred at sand contents between 55 and 70% and pH values near 6. Other variables, including foliar nutrient concentrations, foliar δ¹³C, electrical conductivity, depth of the A horizon and total chemistry of the soil, were also related to hybrid poplar productivity at the local and microsite scales. However, all of these variables were correlated to either soil texture (percent sand) or pH. At the microsite scale within plantations, percent sand was the most important predictor of tree productivity and explained more than 50% of the variability within plantations, although the relationship varied by plantation. In plantations with fine textures, sandier microsites were associated with increased growth while in sandy plantations, finer textured microsites were more productive. As a whole, the growth of the hybrid poplar clone Brooks6 appears to be mostly influenced by a combination of soil water and nutrient availability, the former being impacted by soil texture and the latter being governed by soil pH.     

Estimation and economic evaluation of aboveground carbon storage of <Emphasis Type="Italic">Tectona grandis</Emphasis> plantations in Western Panama

Tropical tree plantations may play an important role in mitigating CO₂ emissions through their potential to capture and sequester carbon from the atmosphere. The Clean Development Mechanism (CDM) as well as voluntary initiatives provide economic incentives for afforestation and reforestation efforts through the generation and sale of carbon credits. The objectives of our study were to measure the carbon (C) storage potential of 1, 2 and 10-years old Tectona grandis plantations in the province of Chiriquí, Western Panama and to calculate the monetary value of aboveground C storage if sold as Certified Emission Reduction (CER) carbon credits. The average aboveground C storage ranged from 2.9 Mg C ha⁻¹ in the 1-year-old plantations to 40.7 Mg C ha⁻¹ in the 10-year-old plantations. Using regression analysis we estimated the potential aboveground C storage of the teak plantation over a 20 year rotation period. The CO₂-storage over this period amounted to 191.1 Mg CO₂ ha⁻¹. The discounted revenues that could be obtained by issuance of carbon credits during a 20 year rotation period were about US$460 for temporary CER and US$560 for long-term CER, and thus, contribute to a minor extent (1%) to overall revenues, only.     

Ectomycorrhizal fungal communities of Dipterocarpus alatus seedlings introduced by soil inocula from a natural forest and a plantation

We attempted to introduce ectomycorrhizal (ECM) fungi onto seedlings of Dipterocarpus alatus (Dipterocarpaceae) by soil inocula collected from tree stands of D. alatus. Top soils collected from beneath the trees of D. alatus in a dry evergreen forest and a 15-year-old plantation were inoculated onto germinating seeds of D. alatus. After 7 months of seedling cultivation, ECM fungal communities in the seedlings were investigated based on the sequences of ITS rDNA. The ECM fungi detected were divided into 19 phylotypes by molecular analysis. Most of the phylotypes were identified as ECM fungal taxa, i.e., Clavulina, Laccaria, Lactarius, Tomentella, Pyronemataceae, and Tricholomataceae. Accordingly, we can confirm that soil inoculation is a simple method to induce ECM formation with diverse fungi in pot cultured seedlings, which would be useful for introducing diverse ECM fungi to dipterocarp plantations.