保留密度对杉木人工林生长和生物量及经济效益的影响

在广西凭祥市热带林业实验中心青山实验场的杉木中龄人工纯林(14年生)中,以不间伐为对照(密度1500株·hm^-2),研究不同保留密度(500、750和1000株·hm^-2)对杉木人工林胸径、树高、蓄积生长量和林分生物量及经济效益的影响。结果表明: 500株·hm^-2处理杉木人工林的平均胸径、树高生长量及大径材蓄积量均最高,分别达20.55 cm、15.70 m、18.31 m³·hm^-2。对照林分活立木蓄积量最高(199.63 m³·hm^-2),显著高于500、750株·hm^-2处理。不同处理乔木层生物量、生态系统生物量和经济效益差异显著。1000株·hm^-2处理乔木层生物量(90.72 t·hm^-2)、生态系统生物量(94.97 t·hm^-2)和经济效益(11.84万元·hm^-2)显著高于其他处理。降低林分保留密度虽然能促进杉木胸径和树高的生长,提高林分的出材径级、大径材比例、单木平均材积和生物量,但不能提高活立木蓄积量。1000株·hm^-2处理是杉木中龄林最适保留密度,林分的总蓄积量、乔木层生物量、生态系统生物量和经济效益分别比对照增加2.3%、5.7%、4.7%和5.8%。     

不同林龄杉木人工林碳储量及其分配格局

基于广西北部杉木主产区45块1000 m²样地的调查,研究幼龄林、中龄林、近熟林、成熟林、过熟林5种林龄杉木植被与土壤碳储量的分配格局.结果表明: 杉木人工林生态系统总碳储量表现为过熟林(345.59 t·hm^-2)>成熟林(331.14 t·hm^-2)>近熟林(299.11 t·hm^-2)>幼龄林(187.60 t·hm^-2)>中龄林(182.81 t·hm^-2).不同林龄碳储量分布格局均为土壤层>植被层>凋落物层,地下部分>地上部分.其中,植被层为34.80～134.55 t·hm^-2,占总碳储量的18.6%～38.9%,随林龄的增加而增加;凋落物层为1.26～2.07 t·hm^-2,占总碳储量的0.4%～1.1%;土壤层为149.24～206.02 t·hm^-2,占总碳储量的61.9%～80.0%.植被层碳储量以乔木层(33.51～133.7 t·hm^-2)最大,占92.8%～98.9%.其中,乔木层各器官碳储量以树干(20.98～95.68 t·hm^-2)最大,占乔木层碳储量的62.6%～72.6%,随林龄的增加而增加;枝、叶碳储量分别占4.8%～11.0%和11.1%～14.2%,随林龄的增加而减小,在过熟林阶段有所上升;根的碳储量占11.3%～12.3%,波动较小,比较稳定.     

阔叶和杉木人工林对土壤碳氮库的影响比较

通过比较我国亚热带地区19年生阔叶人工林和杉木人工林土壤碳氮储量,探讨树种对土壤碳氮库的影响.结果表明：阔叶人工林0～40 cm土层碳储量平均为99.41 Mg·hm^-2,比杉木人工林增加33.1%;土壤氮储量为6.18 Mg·hm^-2,比杉木人工林增加22.6%.阔叶人工林林地枯枝落叶层现存量、碳和氮储量分别是杉木人工林的1.60、1.49和1.52倍,两个树种的枯落叶生物量、碳和氮储量均有显著差异.枯枝落叶层碳氮比值与土壤碳、氮储量之间呈显著负相关.阔叶人工林细根生物量(0～80 cm)是杉木林的1.28倍,其中0～10 cm土壤层细根生物量占48.2%;阔叶人工林细根碳、氮储量均高于杉木人工林.在0～10 cm土层,细根碳储量与土壤碳储量具有显著正相关关系.阔叶树种比杉木的土壤有机碳储存能力更大.     

粤北不同经营措施对人工林年均固碳量的影响

基于粤北林农参与林业碳汇项目的人工林调查数据,分析了粤北不同经营措施对人工林年均固碳量的影响;并运用代表当地普遍经营水平所模拟的材积生长方程计算得出常规经营模式下的杉木碳储量,与参与林业碳汇项目情景所监测的杉木碳储量进行比较。结果表明,不同经营方式下的试验林的年均固碳量具体表现为VI（1.5667 t·hm^-2）-2）-2）-2）-2）-2）-2）,采用科学合理经营模式下的人工林与采用粗放经营模式下的人工林相比较,年均固碳量相对较高;试验林II、III 和IV 的年均固碳量总体呈III IV II 的趋势,而它们的林分密度总体呈III IV II 的趋势,在当地采用了更高林分密度的杉木人工林,其林分的年均固碳量反而较低;杉木的监测碳汇量与预估碳汇量相比有22%-53%的增长,参与林业碳汇项目的杉木人工林碳储量高于当地普遍经营水平的碳储量。该研究有助于了解粤北不同经营措施的人工林固碳情况以及促进林业碳汇的发展。     

杉木人工林冰雪灾害受灾和萌生情况调查及影响因子分析

以九龙山国家级自然保护区的主要公益林杉木人工林作为研究对象,选择具有代表性的受灾区域,自海拔700 m至900 m设置样地,共10块样地,总面积4 000 m2。分析其受2008年初严重冰雪灾害破坏及灾后萌生情况与胸径、树高、尖削度、海拔之间的关系。结果表明： 1）杉木人工林损害严重,其中断冠、断干植株比例较高,而掘根和冻死植株相对较少;杉木具有极强的萌生能力,以断冠杉木的萌生能力最强。2）不同胸径、树高、尖削度的杉木对于冰雪灾害的抵御能力及萌生能力存在一定差异,小径级矮小的个体受灾较重,易被冻死和掘根,大径级的较高个体受灾相对较轻,主要表现为断冠和断干危害,且不同径级下的受灾杉木上部萌生均占较大比例。3）杉木的抵御能力和萌生能力与海拔存在一定的关系,高海拔地区杉木受灾较重,而中海拔地区的杉木萌生能力相对较强。     

杉木人工林冰雪灾害受灾和萌生情况调查

以九龙山国家级自然保护区的主要公益林杉木人工林作为研究对象,选择具有代表性的受灾区域,自海拔700 m至900 m设置样地,共10块样地,总面积4 000 m2。分析其受2008年初严重冰雪灾害破坏及灾后萌生情况与胸径、树高、尖削度、海拔之间的关系。结果表明：1）杉木人工林损害严重,其中断冠、断干植株比例较高,而掘根和冻死植株相对较少;杉木具有极强的萌生能力,以断冠杉木的萌生能力最强。2）不同胸径、树高、尖削度的杉木对于冰雪灾害的抵御能力及萌生能力存在一定差异,小径级矮小的个体受灾较重,易被冻死和掘根,大径级的较高个体受灾相对较轻,主要表现为断冠和断干危害,且不同径级下的受灾杉木上部萌生均占较大比例。3）杉木的抵御能力和萌生能力与海拔存在一定的关系,高海拔地区杉木受灾较重,而中海拔地区的杉木萌生能力相对较强。     

米槠和杉木人工林土壤呼吸及其组分分析

区分森林土壤呼吸组分是了解生态系统碳循环的重要环节。该文以福建省三明市格氏栲自然保护区米槠(Castanopsis carlesii)人工林和邻近的杉木(Cunninghamia lanceolata)人工林为研究对象, 于2012年8月至2013年7月, 采用LI-8100开路式土壤碳通量系统, 通过挖壕沟方法, 测定了土壤呼吸及异养呼吸的速率, 同时测定了5 cm深处的土壤温度和0-12 cm深处的土壤含水量。利用指数模型和双因素模型, 分析土壤呼吸及其组分与土壤温度和土壤含水量的关系, 同时计算了土壤呼吸各组分在土壤呼吸中所占的比例, 并分析了不同森林类型对土壤呼吸及其组分的影响。结果表明: 米槠人工林和杉木人工林土壤呼吸及其组分的季节变化显著, 均呈单峰型曲线, 与5 cm深处的土壤温度呈极显著正相关关系。土壤温度可以分别解释米槠人工林土壤呼吸、自养呼吸和异养呼吸变化的70.3%、73.4%和58.2%, 可以解释杉木人工林土壤呼吸、自养呼吸和异养呼吸变化的77.9%、65.7%和79.2%。土壤呼吸及其组分与土壤含水量没有相关关系。米槠和杉木人工林自养呼吸的年通量分别为4.00和2.18 t C·hm^-2·a^-1, 占土壤呼吸年通量的32.5%和24.1%; 异养呼吸年通量分别为8.32和6.88 t C·hm^-2·a^-1, 分别占土壤呼吸年通量的67.5%和75.9%, 米槠人工林土壤呼吸及其组分的年通量都大于杉木人工林。     

晋西北黄土高原丘陵区不同土地利用方式下土壤碳氮储量

对晋西北黄土高原丘陵区杨树-小叶锦鸡儿人工林、小叶锦鸡儿人工灌丛、杨树人工林、撂荒地和农田5种土地利用方式下土壤碳氮储量进行研究.结果表明: 不同土地利用方式下土壤碳氮含量、碳氮密度和碳氮储量存在显著差异.5种土地利用方式0～20 cm表层土壤碳氮含量和碳氮密度均显著大于20～40 cm和40～60 cm土层.5种土地利用方式同一土层碳氮含量和碳氮密度大小为: 杨树-小叶锦鸡儿人工林>小叶锦鸡儿人工灌丛>杨树人工林>撂荒地>农田;0～60 cm土层土壤有机碳储量大小为:杨树-小-叶锦鸡儿人工林(30.09 t·hm^-2)>小叶锦鸡儿人工灌丛(24.78 t·hm^-2)>杨树人工林(24.14 t·hm^-2)>撂荒地(22.06 t·hm^-2)>农田(17.59 t·hm^-2);土壤氮储量与有机碳储量变化规律相似,杨树-小叶锦鸡儿人工林0～60 cm土层土壤氮储量(4.94 t·hm^-2)最高,其次是小叶锦鸡儿人工灌丛(3.53 t·hm^-2)、杨树人工林(3.51 t·hm^-2)和撂荒地(3.40 t·hm^-2),农田土壤氮储量(2.71 t·hm^-2)最低.杨树-小叶锦鸡儿人工林和小叶锦鸡儿人工灌丛是晋西北黄土高原丘陵区植被建设和生态恢复过程中较好的两种土地利用方式.     

杉木、木荷纯林及其混交林凋落物量和碳归还量

2005年5月-2007年4月,研究了福建省建瓯市水土保持科教园内19年生杉木人工林、木荷人工林和杉-荷混交林凋落物量和碳归还量.结果表明：3种人工林的年均凋落物量分别为2470.85、4171.96和4285.99 kg·hm^-2·a^-1,不同人工林中凋落物均以落叶为主,占林分年总凋落量的68.62%～87.26%.杉木人工林凋落物量在每年的4-5月、7月和12月出现3次较大峰值,而木荷人工林和杉-荷混交林凋落物量的峰值仅出现在每年的3月份.与人工纯林相比,混交林促进了阔叶树种的单株凋落物量增加,但抑制了针叶树种的凋落物量.落叶是3种人工林凋落物碳归还的主体,人工林碳年归还总量大小顺序与年均凋落量相同,其中杉-荷混交林最高(2.12 t·hm^-2·a^-1),杉木人工林最低(1.19 t·hm^-2·a^-1).与针叶和阔叶人工纯林相比,针阔混交林的凋落量大、碳归还量高,具有良好的碳吸存能力.     

雪灾对古田山常绿阔叶林群落结构的影响

为了解雪灾对亚热带常绿阔叶林群落结构的影响,我们于2008年初对右田山24 ha固定监测样地进行了调查.经统计,约1/3的树木遭受重度损伤,1/3的树木遭受轻度损伤.选择生境类型、胸径、物种的物候犁、生长型4个因子,用多项逻辑斯蒂回归分析了这些因子对个体损伤的影响.结果表明:低海拔山谷受损最严重,树木倒伏、折断的倾向最大,高海拔山脊受损最轻.胸径影响树木的受损程度和类型,大致来说,随着胸径的增大,树木受损的比例增大,折断、断梢相对于压弯的可能性逐渐增大,断枝相对折断、断梢的可能性也逐渐增大.常绿物种较落叶物种受损更重.由于上层乔木的庇护,灌木树种受损较为轻微.采用除趋势对应分析(DCA)比较了雪灾前后群落结构的变化,结果表明:在40 m×40 m尺度上,群落的变化与随机变化的零假设有显著差异,这说明冰雪灾害对个体的损伤不是随机的,而是有物种选择性的,如甜槠(Castanopsis eyrei)、木荷(Schima superba)和马尾松(Pinus massoniana)等物种受灾情况显著低于随机损伤的零假设,而青冈(Cyclobalanopsis glauca)、石栎(Lithocarpus glaber)、马银花(Rhododendron ovatum)等物种显著地高于随机损伤的零假设,群落的物种组成在雪灾后发生了显著的变化.     

Enhancement of photosynthetic parameters and growth of Zelkova serrata by arbuscular mycorrhizal fungi under simulated sulfuric acid rain

Plant Ecology - Acid rain (AR) is a frequent environmental issue in southern China that causes damage to the growth and photosystems of subtropical tree species. Arbuscular mycorrhizal fungi (AMF)...     

Differential susceptibility of tree species to oviposition by periodical cicadas

Abstract 1. Periodical cicadas occur widely in deciduous forests of eastern North America and represent the largest insect emergences in the world. Their effects on forest community dynamics, via oviposition damage and root feeding, are potentially great but not well understood. If tree species vary in their susceptibility to cicada oviposition and root colonization, then periodical cicadas may affect ecological interactions among tree species and forest composition. 2. We measured oviposition damage on 63 tree species at 52 sites in southern Indiana, U.S.A. for two broods of periodical cicadas. We compared oviposition damage among different sites, habitats, and tree species. We also measured cicada emergence rates in mature and successional forest habitats and from beneath different tree species. 3. Certain tree species received significantly more oviposition damage than others, and the most and least damaged species were consistent between the two broods. For some species, oviposition damage varied between mature and successional sites. Despite the differences in oviposition rates among species, there was no difference in emergence rates from beneath different tree species, suggesting that initial differences in cicada density among tree species are not maintained through the nymphal life cycle. 4. Cicadas oviposited more at successional sites, but emerged more in mature forest stands, suggesting that successive generations of cicadas represent a shifting mosaic between forests of different ages. As tree species consistently vary in their susceptibility to oviposition damage, periodical cicadas could alter local competitive interactions and therefore affect forest dynamics.     

台风“布拉万”对东北近天然落叶松云冷杉试验林的影响

台风是重要的森林干扰因子之一,会对森林生态系统的结构和功能产生较大的影响。2012年的台风"布拉万"对我国东北地区局部森林造成了严重的破坏。以受灾最重的吉林省汪清林业局的近天然落叶松云冷杉林为对象,采用方差分析和相关分析方法,研究林分结构和地形条件对林木株数损伤率的影响。结果表明:(1)林木损伤类型可分为折断、连根拔起、搭挂、压弯4种,其中连根拔起为最主要的损伤类型,占总损伤株数的52%,台风灾害造成的林木株数损伤率平均为14.09%。(2)径级大小对林木株数损伤率的影响显著。损伤主要发生于径级较小林分处,径级越大,其株数损伤率越小。(3)林木株数损伤率随林分密度的增加有减小的趋势,但在统计学上它们的关系不显著。(4)不同树种间的林木株数损伤率差异显著,落叶松、冷杉等针叶树种损伤株数最多。(5)林分的树种多样性指数与林木株数损伤率无显著的相关性。(6)海拔、坡度和坡位对林木株数损伤率的影响不显著,但坡向的影响显著,东北坡向林分的林木株数损伤率最大。研究结果可以为灾后森林恢复和减少风灾影响的森林培育措施提供依据。     

Tree seedling responses to leaf-cutting ants herbivory in Atlantic Forest restoration sites

Leaf-cutting ants (LCA) are generalist herbivores capable of causing severe plant damage. Negative impacts of ant herbivory vary according to the density of nests and availability of palatable plants; however, it is not yet clear how these herbivores affect tropical forest restoration sites. To investigate how LCA preference affects plant species performance, we evaluated the herbivory of Atta sexdens rubropilosa on native tree species seedlings in Atlantic Forest restoration sites. We expected pioneer species to suffer higher herbivory by LCA when compared with non-pioneer species and that species with higher damage will have poorer growth and higher mortality. The experiment was conducted in three restoration sites in northern Paraná state, southern Brazil, with 1,500 seedlings of 5 pioneer and 5 non-pioneer species. Sites share similar age, stand size, tree species composition, and LCA nest density. The number of attacks, degree of leaf damage, number of leaves, plant height, and survival were recorded. Specific leaf area, leaf polyphenols, flavonoids, tannins, and nitrogen content were analyzed for each species. Plant damage was similar between pioneer and non-pioneer plant species. This could be explained by trait variability among species in each group and by LCA generalist foraging. Preferred species suffered decreases in growth and survival. Less preferred species suffered fewer ant attacks and no change in performance. Results suggest that ant herbivory can influence plant species establishment and thus species composition in restoration sites by reducing performance and increasing mortality of some, but not all species, making LCA an important ecological filter.     

Elephant herbivory,frost damage and topkill in Kalahari sand woodland savanna trees

Questions: Which factors best predict the probability of elephant and frost damage in Kalahari sand woodland savanna? What is the association between tree mortality and the disturbance regime? Location: Western Zimbabwe. Methods: Elephant and frost damage, topkill, and whole‐plant mortality were quantified in ten common tree species in a Kalahari sand savanna in Zimbabwe. Individual trees were tagged in 20 plots and monitored over a two‐year period. A model selection approach was used to test the association between the probability of damage and size, prior damage, and neighbourhood effects, and to investigate the effect of damage on mortality. Results: Elephant damage differed strongly among species, and was not influenced by neighbourhood effects or prior disturbance. Frost damage also varied across species, and declined as a function of stem size and neighbourhood tree cover, and ‐ against expectations ‐ prior disturbance. Topkill increased as a function of elephant and frost damage, but was lower in previously damaged than in undamaged trees. Conclusions: Frost and elephant damage are influenced by community composition, and frost damage is also correlated with community structure and prior disturbance. Frost is an important and generally overlooked disturbance agent in southern African woodlands, where it may play a key role in association with other disturbance factors ‐ such as elephant herbivory ‐ that reduce woodland canopy cover.     

Arbuscular mycorrhizal fungi protect a subtropical tree species exposed to simulated acid rain by accelerating photosynthetic ability,antioxidant enzymes and osmolyte accumulation

丛枝菌根真菌对其宿主光合能力、抗氧化酶和渗透物质积累的促进作用 及其抗酸雨机制的探讨 酸雨在中国南方发生频繁,对亚热带树种生长具有明显抑制作用。以往研究表明,丛枝菌根真菌(AM真菌)可以缓解酸雨对宿主植物的胁迫效应。榉树(Zelkova serrata)为中国南方主要经济树种之一,其如何与共生AM真菌协同、增强其抗酸雨胁迫的能力是本项研究所要探讨的关键科学问题。通过温室控制实验,将榉树幼苗随机接受4个水平的AM真菌接种处理(接种灭菌菌种;单独接种Rhizophagus intraradices;单独接种Diversispora versiformis;接种这两种菌种的混合菌种)和3个pH水平(pH2.5、pH4.0和pH5.6)的硫酸型酸雨和硝酸型酸雨处理组成的12个处理组合,同时测定其生长、光合性能、抗氧化酶、渗透调节和土壤酶的响应格局。研究发现酸雨处理显著降低了非菌根榉树幼苗的总干重、总叶绿素含量、叶片净光合速率和可溶性蛋白的含量;接种AM真菌,特别是接种混合菌种,显著提高了强酸胁迫下榉树幼苗的总干重、光合性能、丙二醛、过氧化物酶、超氧化物歧化酶、可溶性蛋白和根系酸性磷酸酶活性。此外,菌根效应依赖于AM真菌的种类和酸胁迫的梯度。本研究 结果表明,AM真菌对榉树幼苗抗酸胁迫的调控作用主要源于调节宿主植株光合能力、抗氧化酶和渗透物质的积累。榉树与其共生AM真菌在应对酸胁迫上协同机制的解析为该树种在中国南方酸雨区的栽培提供理论基础、具有重要的实践指导意义。     

广西南宁市园林树木白蚁发生种类及危害情况

2009年311月对南宁市园林树木白蚁为害情况进行了调查。结果表明,台湾乳白蚁Coptotermes formosanus Shiraki是危害园林树木的优势种;调查的57种树木中,45种树木受到了白蚁的侵害,占总数的78.95%,树木受害株率达13.11%,严重受害株率为1.66%。银桦、侧柏和樟树等树种受白蚁危害最为严重。     

东江林场20个乡土阔叶树种拟木蠹蛾为害调查

拟木蠹蛾Arbela spp.是华南地区严重影响人工林质量和稳定性的一类钻蛀害虫。本研究以广东省东江林场20个乡土阔叶树种人工幼林为研究对象,调查分析拟木蠹蛾对不同树种的为害状况及其与林木生长的关系。结果表明:7 a生时共有5个树种受到拟木蠹蛾为害,分别为西南桦Betula alnoides、海南红豆Ormosia pinnata、山杜英Elaeocarpus sylvestris、翻白叶Potentilla fulgens和楝叶吴茱萸Evodia glabrifolia,8 a生时新增1个受害树种——秋枫Bischofia javanica;受害树种生长表现和感虫情况均差异显著(P0.05),但种内感虫个体生长表现与未感虫个体差异不显著(P0.05);这些受害树种的虫口高度分布范围不同,生长较快的翻白叶和西南桦,其虫口主要分布在树冠以下,生长速度中等的海南红豆和山杜英的虫口分别集中在树冠下缘附近和树冠下缘上部,生长较慢的楝叶吴茱萸和秋枫的虫口则分别多在树冠下缘附近及其下部和树冠下缘及其上部,据此初步提出以枝下高作为主要参考指标分析其虫口高度分布特征。研究结果补充完善了拟木蠹蛾发生规律和为害特征方面的资料,且为该区域营建混交林的树种选择提供参考。     

The Tropical Forests of Southern China and Conservation of Biodiversity

Species-rich tropical forests once occurred along much of China’s southern border, from southeastern Xizang (Tibet) and southern Yunnan to southwestern Guangxi, southern Taiwan and Hainan, mainly south of 22°30’N latitude. These Chinese forests are similar to Southeast Asian lowland tropical forests in their profiles and physiognomic characteristics, floristic composition and species richness. Studies of these southern forests in China are reviewed. Complete vegetation studies on the physiognomy and floristic composition have been done in southern Yunnan, Hainan and southwestern Guangxi. Forest fragmentation, dispersal patterns of trees, and the maintenance, population dynamics, phylogenetic community structure, tree functionality and phylogenetic diversity and conservation of these tropical Chinese forests have also been studied. Major changes in land use in China have resulted in an increase in rubber and Eucalyptus plantations and a decrease in the extent of southern forests. The direct results have been fragmentation and loss of biodiversity. The underplanting of economic crops in native forests also threatens to destroy saplings and seedlings, causing the forest to lose its regenerative capacity. Limiting further expansion of monoculture tree plantations, restricting underplanting, and promoting multi-species agroforestry systems are needed in China to conserve the biodiversity of its forests.     

基于聚类分析的广东省乡土阔叶树种分布研究

利用《中国植物志》、《广东植物志》等资料并结合实地野外踏查记录数据,获取了广东省1152个乡土阔叶树种的分布信息,在对其进行聚类分析的基础上采用多响应置换过程、指示种分析和Kruskal-Wallis检验,研究广东省乡土阔叶树种的分布特征。结果表明,乡土阔叶树种在广东省的分布具有较明显的纬度地带性,且可划分为3个分布区:Ⅰ区主要出现在广东省北部山区的中亚热带,树种丰富度的均值最大(376.5),缺萼枫香(Liquidambar acalycina)、椿叶花椒(Zanthoxylum ailanthoides)、伞花木(Eurycorymbus cavaleriei)等为主要指示种;Ⅱ区主要出现在广东省中部的南亚热带,树种丰富度的均值为339.8,肉桂(Cinnamomum cassia)、狭叶山黄麻(Trema angustifolia)、黄叶树(Xanthophyllum hainanense)等为主要指示种;Ⅲ区主要出现在广东省南部沿海的热带北缘,树种丰富度的均值最小(206.5),秋茄树(Kandelia candel)和山油柑(Acronychia pedunculata)等为主要指示种。