Gas exchange responses of two Eucalyptus species to salinity and waterlogging

The effects of salinity and waterlogging on stomatal conductance, net photosynthesis and transpiration of 3-month-old Eucalyptus camaldulensis Dehnh. and Eucalyptus lesouefii Maiden seedlings were studied under greenhouse conditions. Under non-saline conditions, waterlogging induced stomatal closure in both species. However, the stomata of E. camaldulensis reopened after five weeks, when adventitious roots were produced. Relative to that of controls, height growth of waterlogged seedlings was greater in E. camaldulensis than in E. lesouefii, as were rates of photosynthesis and transpiration. In a freely drained medium, high salinity reduced rates of seedling height growth and photosynthesis, relative to those in controls, less in E. lesouefii than in E. camaldulensis. In both species, height growth, stomatal conductance and photosynthetic rate were lowest under conditions of saline waterlogging.     

桉树无性系在桂南地区生长对比

在相同立地条件下对广西钦州地区5年生的5个桉树无性系进行生长对比试验,结果表明:5个无性系在树高、胸径、蓄积量生长方面差异均达到显著水平;广林韦赤桉（Eucalyptus wetarensis×E.camaldulensis）3号和广林柳窿桉（E saligna×E.exserta）9号蓄积量占有较大的优势;无性系生长...     

海南岛东部地区桉树树种/种源试验*

在海南岛东部进行的桉树１１个树种７９个种源试验，５年的结果表明，不同树种种源间生长差异极显著，来自印度尼西亚Ｍｔ．ｍａｎｄｉｒｉ的尾叶桉１２８９５种源是所有参试树种／种源中表现最好的，树高、胸径和每公顷材积分别为１３．８２ｍ、１２．５４ｃｍ和１２８．３４ｍ３。同一树种种源间生长差异也极显著，最佳种源的每公顷材积与最差种源相比，尾叶桉为８．４６：１，细叶桉５．８６：１，赤桉５．３２：１和巨桉３．０４：１。细叶桉、赤桉和巨桉种源树高、胸径和材积生长与原产地纬度显著负相关，尾叶桉种源与原产地海拔高极显著负相关。本文提出了适合海南岛东部地区生长的树种和种源。     

24个产地南方红豆杉在两试验点的生长差异及其选择

[目的]对南方红豆杉产地试验林分别在不同年份进行全林生长性状测定,评估南方红豆杉产地早期选择的准确性和可靠性。[方法]在浙江龙泉和浙江安吉两地同时开展了南方红豆杉产地试验,通过对24个产地南方红豆杉树高、胸径和冠幅等生长性状的10 a跟踪观测,以明确早期选择的准确性并优选出一批生长优良的产地。[结果]浙江龙泉和浙江安吉两地点24个产地南方红豆杉10年生树高、胸径和冠幅变异系数分别达6.58%、15.14%、11.18%和9.17%、17.18%、17.14%。浙江龙泉点不同产地南方红豆杉10年生树高和胸径均值分别比浙江安吉点高29.02%和10.88%。浙江安吉和浙江龙泉两地点24个产地南方红豆杉7年生树高与10年生树高的相关系数分别为0.780(P0.01)和0.769(P0.01),均大于两地点4年生树高与10年生树高的相关系数0.479(P0.05)和0.649(P0.01)。[结论]南方红豆杉生长性状具有显著的产地、地点以及产地×地点的互作效应。以10年生树高、胸径以及7 10年生树高和胸径生长量均值为筛选标准,采用独立淘汰法分别从龙泉点和安吉点选出7个和3个速生优良产地。     

广西大青山柚木人工林生长过程研究

[目的]研究柚木人工林生长过程及其与气象因子的相关性,为柚木抚育经营提供理论依据。[方法]以优良、中等和差3种生长类型的30余年生柚木人工林为对象,基于样地调查,选取优势木、平均木、被压木进行树干解析,对比分析其生长过程,应用灰色关联分析法揭示气象因子对柚木生长的影响。[结果]表明:3种生长类型林分柚木胸径、树高和材积生长过程基本一致,各分级木的生长过程亦相似,其胸径平均和连年生长量随年龄的增大呈先增加后逐渐降低的趋势,树高生长整体上呈下降趋势,材积生长则呈递增趋势。各优良林分的林木及各类型林分的优势木,其胸径、材积平均和连年生长量较大,速生期持续时间长,生长衰减慢,而其树高生长量的优势相对不明显;30余年生时柚木尚未达数量成熟龄。各类型林分间柚木生长与气象因子关系的差异仅体现在胸径,优良林分胸径连年生长量主要受极端低温影响,而中等和差林分则与年均降水量相关性最大;各分级木间柚木生长与气象因子的关系无明显差异;影响树高和材积连年生长量的最主要气象因子分别为年均降水量和年均气温。[结论]柚木各生长类型及分级木的生长过程整体趋势基本一致,其差异主要体现在生长量大小和快速生长期长短。约30年生柚木人工林仍未达到数量成熟,后期抚育经营对于其优质大径材高效培育仍不可忽视。     

兴安落叶松天然林林木直径与树高分布的分层特征

[目的]通过分析大兴安岭呼中林区兴安落叶松天然林胸径和树高的一元、二元分布特征,揭示脆弱地带森林群落的林木大小分布特征。[方法]在大兴安岭呼中林场设置3种不同类型兴安落叶松林固定样地,利用整体和分层的方法,对样地林分胸径和树高的变化规律以及两者之间的关系进行研究。[结果]表明:(1)草类-落叶松林直径分布为单峰分布,其他2块样地为双峰分布; 3块样地林木直径分布均呈左偏。杜鹃-落叶松林树高分布为多峰分布,其他2块地均为单峰分布; 3块样地林木树高分布均呈右偏。(2) 3块样地上、下层林木的直径分布均为单峰分布,上层木直径分布均呈左偏,下层木直径分布草类-落叶松林右偏,杜鹃-落叶松林左偏,杜香-落叶松林为近似正态。杜鹃-落叶松林的树高上、下层分布为双峰,其他2块样地均为单峰,3块样地上层木树高分布均左偏,而下层木树高分布均右偏。(3)草类-落叶松林和杜鹃-落叶松林小径阶林木株数占绝大多数。3块样地林分中树高与胸径的比值在小径阶林木中明显大于大径级林木。草类-落叶松林和杜鹃-落叶松林上层木中小径阶林木株数所占比例稍大,杜香-落叶松林和杜鹃-落叶松林下层木中大径阶林木株数比例稍大,但3块样地上层和下层木树高与胸径的比值在大小径阶林木中均无明显差异。[结论]高密度的杜鹃-落叶松林平均树高要高于低密度的杜香-落叶松林和草类-落叶松林平均树高,而平均胸径无明显差异。3块样地林分中树高与胸径的比值小径阶林木中明显大于大径级林木,但其差异在上层和下层林分中均表现不明显。     

不同坡向坡位对桉树造林成活率的影响及生长效应分析

分析不同坡向、坡位对桉树造林成活率、树高及胸径的影响。采用桉树组培苗木进行造林试 验,以1年生桉树人工林样地调查数据为研究对象,调查造林效果,记录样地坡向、坡位,并实测每 株林木的树高和胸径。结果表明,坡向或坡向与坡位二者的交互作用对桉树造林成活率、树高、胸 径的影响程度均强于坡位,其中坡向对桉树造林成活率及当年生长量的影响程度最大;不同坡向对 桉树造林成活率及当年生长量的影响极为显著,造林成活率受坡向的影响最大,不同坡位对桉树造 林成活率及当年生长量的影响不显著,坡位对造林成活率、树高、胸径的影响较小;从阳坡、半阳坡、 半阴坡、阴坡光照依次逐渐减弱,桉树造林成活率分别为90.83%、84.18%、77.34%、75.95%,平均 树高从8.59 m减小到7.57 m,平均胸径从6.26 cm 减小到5.43 cm;从阳坡到阴坡,桉树造林成活 率、平均树高、平均胸径均呈现逐渐减小的趋势,而随不同坡位的降低,其变化不明显,但均在中坡 表现出最小值。     

Root distribution of Eucalyptus grandis and Corymbia maculata in degraded saline soils of south-eastern Australia

Planting trees, in farm forestry enterprises, to control rising watertables is an increasing practice for both economic and environmental benefits. One central biophysical issue which determines the effectiveness of trees to control groundwater is the ability of trees to grow roots through degraded soils and take up groundwater. We investigated the effect of soil properties, especially the presence of shallow watertables and site preparation practice, on the vertical and horizontal distributions of Eucalyptus grandis W. Hill ex Maiden and Corymbia maculata (Hook.) K.D. Hill and L.A.S. Johnson roots. In order to improve the reliability of root data, we measured root growth and distribution by three different methods – (i) number of roots intercepting the vertical plane of the soil profile, (ii) root length density in soil cores taken at different depths but in the horizontal plane of the profile, and (iii) root length density in soil cores in the vertical plane at different radial positions from trees and compared the results. Two experimental sites were established in flood-irrigated, farm forestry plantations on contrasting soils in the Murray Riverina region of south-eastern Australia. At one site (Norwood Park), we studied a 58-month-old stand of E. grandis growing in clay loam overlaying medium clay, saline, sodic and alkaline subsoil with a saline (11.5 dS m⁻¹) watertable at 2.8 m depth. Here, there were few roots growing above the watertable. The Karawatha site had adjacent stands of 46-month old E. grandis and C. maculata growing in a sandy, neutral and non-saline soil with a shallow (3.1 m deep) non-saline (2.8 dS m⁻¹) watertable. Here roots proliferated above the watertable in both species but to a much greater extent under C. maculata than under E. grandis. Root distributions in the surface soil were similar at all sites but differences in root growth in the capillary zones paralleled differences in groundwater uptake by trees. We conclude (i) that appropriate matching of species with site characteristics, especially soil and groundwater properties, will enhance tree growth and groundwater uptake and (ii) that extensive planting of C. maculata over non-saline watertables maximises the chances of achieving the multiple objectives of regional groundwater control, fast growth rates and reduced irrigation demand.     

Application of theoretical growth functions for Mongolian oak (Qurcus mongolica)

Four alternative functions are used for fitting tree height and diameter growth models for mongolian oak. (Quercus mongolica Fisch. et Turcz.). The data set includes 1250 random trees and 755 dominant trees coming from 510 temporary plots. The resultsshow that the Richards function is the best model for predicting height. diameter at breast height (DBH) and dominant height from age. The average growth curve of dominant height is used as a guide curve for the construction of a site index table which is partially validated using an independent data set. The Mitscherlich function is the best model for estimating height and dominant height from DBH. (Responsible Editor: Chai Ruihai)     

赤桉优良家系选择分析

以8年生赤桉种源试验林的141个家系为材料,进行3个生长性状遗传变异分析,并根据各家系单株材积表现进行优良家系选择,结果表明：树高、胸径、材积3个性状在家系水平存在极显著的差异;家系遗传力与单株遗传力具有同样的规律：胸径遗传力〉树高遗传力〉单株材积遗传力。由遗传相关系数来看,以家系单株材积表现进行赤桉优树选择比其他性状更具指导意义。以表现水平法和T检验,2个不同参照标准,选择出103、106、108号等13个优良家系,其中前3名家系单株平均材积分别达0.1120m3、0.0944m3和0.0936m3。     

北美鹅掌楸人工林生长规律及早期选择可行性探究

[目的]北美鹅掌楸为优良的珍贵用材树种,研究其生长发育规律及生长性状早晚期相关对于北美鹅掌楸人工林高效培育有重要的指导意义。[方法]本文利用树干解析的方法对江苏句容24年生的北美鹅掌楸人工林生长规律研究,并在此基础上进行胸径、树高和材积性状的年年相关分析以及早期选择效率评价。[结果]研究结果表明:北美鹅掌楸胸径、树高从6 a进入快速生长期,持续到17 a,而材积则在1 10 a增长缓慢,12 a后进入速生期,生长速率在20 a达到最大,22 a后逐渐降低,林分接近数量成熟。生长性状的年年相关及早期选择效率分析结果表明:胸径、树高在6 a与18 a显著相关,材积在6 a与16 a达到显著相关,且此时选择效率最高;若以24 a为伐期年龄早晚相关分析,胸径、材积在16 a与24 a生长量达到显著相关水平,而树高则为14 a。[结论]北美鹅掌楸胸径、树高早期增速较快,进入中壮龄阶段竞争加剧,个体间分化增大。随着林分年龄的增长,研究获得的早期选择年龄也相应地延迟。从加速育种角度,在6 a进行早期选择较为合理,而在培育大径材北美鹅掌楸方面可以16 a之后再进行疏伐选择。     

山地木麻黄种源在海南临高的遗传变异及选择

[目的]研究山地木麻黄种源间抗风性、生长及形质性状的遗传变异规律,为山地木麻黄的良种选育和种质资源的合理开发利用提供科学依据。[方法]以27个山地木麻黄种源为试验材料,于造林后2、5、7 a时测定山地木麻黄种源的树高、胸径、单株材积和保存率等数量性状,并于造林后7 a时调查主干分叉习性(AP)、主干通直度(SFS)、侧枝密度(DPB)、侧枝直径(TPB)、绿色小枝长度(LDB)、侧枝分枝角(APB)、侧枝长度(LPB)等形质性状以及抗风性(RES),通过方差分析、相关性分析及遗传参数估算揭示其遗传变异规律。应用坐标综合评定法对山地木麻黄种源进行综合评定。[结果]表明:造林后2、5、7 a时,27个山地木麻黄种源间保存率和抗风性差异显著(P0.05);对造林后7 a时保存率较高的18个种源进一步分析显示,上述3个年份各种源间树高、胸径和单株材积等生长性状均存在极显著差异(P0.01);7 a时,TPB、APB、LDB、AP和SFS等形质性状在种源间亦存在显著或极显著差异;生长性状的种源遗传力明显高于形质性状,二者分别受中度或中度偏下和低度遗传控制;随着林龄的增长,树高的遗传变异系数变化不大,而胸径和单株材积的遗传变异系数呈先增加后降低的趋势,树高、胸径、单株材积的遗传变异系数分别为11.89%~12.30%、11.67%~13.67%、30.20%~38.11%;7 a时,形质性状的遗传变异系数为3.84×10~(-5)%~5.56%。性状间相关分析表明:树高作为山地木麻黄早期选择性状较适宜。[结论]依据坐标综合评定法,筛选出17877、19489和19490等3个优良种源,可在生产上大面积推广。     

造林密度对米老排人工林初期生长的影响

[目的]探讨不同造林密度对米老排人工林生长的影响规律,为米老排人工林定向培育过程中的密度控制提供参考。[方法]以广东省云浮市造林后6年生米老排人工林为研究对象,对不同造林密度(625、833、1 111、1 667、2 500株·hm~(-2))林分平均树高、优势木高、胸径、保留率和枝下高等生长指标进行连续4年调查。[结果]表明:随着造林密度的增大,米老排林分平均胸径、胸径连年生长量、保留率、单株材积和材积连年生长量均显著减小,而枝下高、林分蓄积量和蓄积连年生长量显著增加。在一定密度范围内,造林密度对林分高生长的影响比较小。造林后第6年,密度1 667株·hm~(-2)林分的平均树高最大(11.4 m),优势木高以密度1 111株·hm~(-2)林分的最大(13.3m),树高连年生长量以密度625株·hm~(-2)林分的最大(1.5 m·a~(-1));密度625株·hm~(-2)林分的平均胸径、胸径连年生长量、单株材积和材积连年生长量均最大,分别为14.3 cm、2.5 cm·a~(-1)、0.097 3 m~3和0.038 2 m~3·a~(-1),比密度2 500株·hm~(-2)林分的分别增加27.7%、81.0%、49.0%和82.4%;密度2 500株·hm~(-2)林分的枝下高、蓄积量和蓄积连年生长量均最大,分别为6.0 m、149.4 m~3·hm~(-2)和44.8 m~3·hm~(-2)·a~(-1),分别是密度625株·hm~(-2)林分的2.61、2.52、1.95倍。[结论]分析了造林密度对米老排初期生长的影响,对米老排人工林的培育具有理论指导意义。     

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。     

引进种源印度黄檀优株选择及优良无性系选择与评价

[目的]印度黄檀Dalbergia sissoo(Roxb.)是一种经济价值比较高的用材树种,对印度黄檀优株选择及优良无性系筛选,可以为印度黄檀优良品种选育提供理论指导和支持。[方法]本研究测定4种国外引进种源(N0、N2、I4和H6)印度黄檀母株株高和胸径,选择出20棵优株;并通过嫁接进行无性系苗木繁殖,测定2年生无性系苗木胸径和株高,比较分析了20个无性系株高和胸径,筛选出优良无性系用于印度黄檀优良品种选育。[结果]4个种源的印度黄檀母株株高和胸径变异系数较大,选择的20棵优株株高和胸径约等于或大于母株平均株高和胸径的130%;9和10号无性系株高和胸径均明显大于其它无性系,且变异系数远远小于母株;其次为12、18、19和20号无性系;9和10号优株,树干较直,胸径较大,超过母株平均值的170%;9和10号无性系株高和胸径均超过对照的130%,可作为优良无性系。[结论]本研究选择了20棵印度黄檀优株,并繁殖出20个无性系,筛选出9和10号作为优良无性系,用于之后的印度黄檀优良品种的选育。     

桉属树种/种源试验

广东省江门地区为调整人工林树种结构 ,提高人工林的产量和质量 ,发展以阔叶树种为主的人工林。现桉树 ( Eucalyptusspp.)已成为该市营造短轮伐期工业用材林的主要树种 [1] 。本试验的目的在于通过从澳大利亚引进桉属树种 ,进行桉属树种 /种源试验 ,为江门市选出更适合当地生长的优良桉树树种和优良种源 ,促进该地区桉树人工林的发展。1　试验地概况　　试验地位于广东省开平市镇海林场 ,2 2°2 5′～ 2 2°40′N,112°15′～ 112°45′E。属南亚热带气候 ,年平均温度 2 2 .1℃ ,极端最高温度 38.3℃ ,极端最低温度 1℃ ,年平均降水量 182…     

Sprouting characteristics of a subtropical evergreen broad-leaved forest following clear-cutting in Okinawa,Japan

This study explores the sprouting characteristics of an evergreen broad-leaved forest after clear-cutting based on a survey of 1,893 stumps of 62 tree species in Okinawa, Japan. The sprouting capabilities of the stumps varied among tree species. The stumps of 60 species could produce sprouts, while those of the other two species could not. In 10 of the sprouting species, the mean sprout-stem number was higher than 4.0 stems per stump; nine sprouting species showed low sprouting capabilities. Additionally, Castanopsis sieboldii and Schima wallichii, the dominant species, exhibited high sprouting capabilities. Further, the sprouting capabilities varied with stump diameter at breast height (DBH). Stumps with a larger DBH tended to have a higher mean number of sprout stems per stump, higher DBH, and higher tree height than the smaller stumps. The forest stands regenerated by sprouting might recover into a tree community similar to that before clear-cutting.     

Fruit production ofAcacia tortilis andA. nilotica in semi-arid Ethiopia

Dry, dehiscent fruits ofAcacia tortilis provide important fodder for pastoral livestock in dry seasons on the central Borana Plateau, fruits ofA. nilotica may also be useful during drought. Information was needed on fruit yield to assess what these species could contribute to improved calf feeding systems based on local resources. Fruit production of 10 mature trees per species was measured at five sites for seven months during 1988–9 (n=50 per species). Fruit yields varied according to site, season and species x site (each atP<0.001), but there was no main effect of species (P=0.13). Yields were not correlated with trunk diameter at breast height (DBH) or canopy area within or across species (P>0.05 in all cases). Yields ranged from 0 to 40 kg DM per tree overall, with an average of 5.3 kg DM per tree (or 65 g DM/m² of canopy area). This average tree had a DBH of 26 cm and a canopy area of 81 m². Low and highly variable fruit yields appear to constrain enhanced use of these species here. These species warrant further attention in research and development, however, given their strategic value as forage resources in pastoral systems and their ability to persist in variable environments.     

Estimating plot-level forest structural attributes using high spectral resolution ASTER satellite data in even-aged Eucalyptus plantations in southern KwaZulu-Natal,South Africa

This study assessed the suitability of both visible and shortwave infrared of ASTER reflectance bands and various vegetation indices for estimating forest structural attributes of Eucalyptus species. The study was conducted in even-aged monoculture plantations of E. grandis and E. nitens in the southern KwaZulu-Natal Midlands of South Africa. Empirical relationships between forest structural attributes, i.e. stems per hectare (SPHA), diameter at breast height (DBH), mean tree height (MTH), basal area and volume, and ASTER data were derived using correlation and canonical correlation analysis (CCA). The results indicated weak relationships between the studied forest structural attributes and ASTER data. In the younger plantation stands (4–6 years) the adjusted R ² values from CCA regression for SPHA, DBH, MTH, basal area and volume were 54.2, 63.5, 33.8, 25.4 and 30.3, respectively. The adjusted R ² values in the mature stands (7–9 years) were distinctly weaker with values of 50.7, 55.8, 25.1, 20.2 and 27.3 for SPHA, DBH, MTH, basal area and volume, respectively. The results imply that ASTER satellite data are not applicable to forest structural attribute estimation in commercially managed forest stands.     

Growth and nut production of black walnut in relation to site, tree type and stand conditions in south-central United States

Black walnut (Juglans nigra) is a prime tree species for agroforestry practices in the United States providing highly prized wood and nuts for human consumption and wildlife. In 54 black walnut stands in south central United States, the site index (i.e., mean dominant height [DH], at age 25 years) ranged between 5.2 and 21.4 m, and was independent of stand density. There were no differences in height and stem diameter (DBH) growth rates between stands with improved varieties and native stock. Most stands were in a “free growth” stage because of either early age or wide spacing. Mean annual increments in DBH and height were positively related both for improved varieties and native stock. Understory competition had a substantial detrimental effect on DH. In a 26 year-old stand, trees growing within Kentucky blue grass (Poa pratensis) had a site index 5 m greater than trees growing within tall fescue (Festuca arundinacea). Predicted nut yields in 2002 varied between 0 and 1370 kg of hulled nuts per ha. Improved varieties had, in general, higher nut yields than predicted from a nut yield-DBH equation developed for individual trees. Nut yields were highly variable both within and among stands, and were related to DBH in native stock but not in improved varieties.