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。     

尾叶桉萌芽林施肥试验初报

通过分析施肥对尾叶桉萌芽林胸径、树高及材积等生长因子的影响。结果表明不同施肥量对萌芽林生长的影响有显著差异，以每株施复合肥１５０ｇ对萌牙林生长作用最大，２年生尾叶桉萌芽林平均胸径８．２３ｃｍ，平均树高１３．５３ｍ，平均单株材积０．０３７４ｍ＾３，单位面积蓄积量６１．７ｍ＾３／ｈｍ＾２。     

尾叶桉种源—家系生长与抗风性选择

对尾叶桉11个种源174个家系2．3年生试验林的生长与抗风性进行了浏定，结果表明：尾叶桉种源间、家系间、区组间的差异以及种源与区组、家系与区组的交互作用均极显著。台风对尾叶桉的危害主要表现在造成风折，占整个试验林木的22．5％。尾叶桉种源，家系的生长性状与其抗风性能呈显著的负相关；通过对174个家系的生长和抗风性的综合指数选择，初步选出了32个适合粤西生长的既抗风、生长又快的家系。     

贫瘠丘陵地短轮伐期薪材树种生长过程的研究

尾叶桉、细叶桉、赤桉、粗皮桉、巨桉（简称桉树类，下同）和马占相思、粗果相思及薄果相思（简称相思类，下同）等８个树种，在水土严重流失的贫瘠丘陵地经７年的生长试验，结果表明：除巨桉和细叶桉在该立地生长较缓慢外，其余６个树种生长快，产量较高。尤其是尾叶桉和马占相思，７年生胸径年均生长量在１．０ｃｍ以上，单位面积生物量（地上部分鲜重，下同）为５２．６９ｔ／ｈｍ２和４３．６７ｔ／ｈｍ２。不同树种的生长比较：桉树类树种（除巨桉外）４年生以前胸径、树高和生物量生长均比相思类树种生长快，４年后相思类树种逐渐赶上或超过桉树类树种。性状生长高峰期分别为：胸径桉树类为２年生（细叶桉１年生）、相思类为３～４年生，树高桉树和相思类均为１年生，生物量桉树类为２～３年生、相思类为４～６年生。     

华南地区桉属树种种源生长表现

在华南地区，桉属树种的多点试验结果表明，细叶桉和赤桉的优良种源在各种不同的立地条件下，其近期保存率和立木蓄积量都比当地原主栽树种窿缘桉高１倍以上；在较好的立地条件下，尾叶桉产量最高，该树种最优种源２年生立木蓄积量比最差种源大１３９．２％，细叶桉５年生立木蓄积量最好种源比最差种源大２１．１１倍，赤桉５年生立木蓄积量最好种源比最差种源大６６％。     

巨尾桉无性系山地引种造林效果的研究

通过对引进巨尾桉无性系与巨桉,尾叶桉进行山地造林试验３年的研究结果表明,巨尾桉无性系不仅能适宜本地区山地栽培,而且,生长快,３年生平均树高１２．１ｍ,胸径１２．３ｃｍ,单株带皮材积０．０７２８ｍ＾３,去皮材积０．０５７４ｍ＾３,比尾叶桉分别增长２３．５％,２８．１％,９２．１％和１４０．２％,比巨桉分别增长１３．１％,１９．４％,５６．６％和５１．５％。它还具有树干通直圆满,树皮较薄,冠径比小,出     

尾叶桉不同密度与株行距配置造林及其效益研究

对５年９个月生三种密度（１６６６株／ｈｍ＾２、２２２２株／ｈｍ＾２和３３３３株／ｈｍ＾２）两种配置（１６６６株／ｈｍ＾２,株行距分别为２ｍ＊３ｍ、１ｍ＊６ｍ）尾叶桉试验林的研究表明：密度越大的林分,其冠幅、胸径、树高、单株材积、蓄积量就越小;     

大叶相思种源选择试验

对从昆士兰引进的５个大叶相思种源及１个本地种源，在琼海试点和花都试点进行试验，结果表明，引进种源在前者的生长表现均比后者好，不同种源在同一试验点比较，以１５６９７和１５４８３种源生长快，产量高，年平均生长琼海试点和花都试点分别为胸径２．０ｃｍ和１．３树高，树高２．３ｍ和１．３ｍ，生物量２５．３６ｔ／ｈｍ＾２和１３．６３ｔ／ｈｍ＾２以上，明显地优于其余各种源。花都试点５个引进种源树高，胸径生长量及生     

尾叶桉幼林地上部分生物量及养分循环的研究*

论述了２－３年生尾叶桉幼林地上部分生长、生物量积累和生物量在树木各器官及各径阶中的分配，林分净生产量，树木各器官及凋落物的养分含量和林分的养分循环。２年生时林分的生物量为２２．９ｔ／ｈｍ＾２，其中干材占６０．２％，皮占８．９％，枝占１４．７％，叶占１６．２％。３年生时林分生物量为４０ｔｈｍ＾２，其中干材占６３．６％，皮占７．７％，枝占１４．１％，叶占１４．６％。年净生产量为２０．５ｔ／ｈｍ＾２，约     

尾叶桉种源─家系生长与抗风性选择

对尾叶桉11个种源174个家系2 3年生试验林的生长与抗风性进行了测定,结果表明:尾叶桉种源间、家系间、区组间的差异以及种源与区组、家系与区组的交互作用均极显著。台风对尾叶桉的危害主要表现在造成风折,占整个试验林木的22 5%。尾叶桉种源 家系的生长性状与其抗风性能呈显著的负相关;通过对174个家系的生长和抗风性的综合指数选择,初步选出了32个适合粤西生长的既抗风、生长又快的家系。     

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…     

Growth potential of Eucalyptus cypellocarpa as an alternative species for the mid-altitude summer rainfall region of South Africa

Eucalyptus grandis is predominantly cultivated in the humid, warmer temperate, subtropical regions in South Africa for pulp and paper production because of its rapid growth and desirable wood properties. With forestry expanding into mid-altitude drier and warmer, or drier and colder sites, the growth of E. grandis has been compromised by unsuitable growing conditions and, therefore, the search to identify reasonably well-performing species/provenances for such sites has extended to summer rainfall provenances of E. cypellocarpa for pulp and paper production. Seed collected from New South Wales, Australia, comprising provenances from Hanging Rock, Nullo Mountain, Wingello State Forests and Kaputar Mountain National Park was established in provenance/progeny trials on three sites in South Africa (Windy Gap, Petrusvlei and Speenkoppies). Trials were planted at 1 667 stems ha^?1, in single-row plots of six trees, with four replications in one balanced and two unbalanced lattice designs. Commercial seed of other eucalypts and clones was used as controls. Diameter at breast height and height were measured at 96 months at Windy Gap, and 72 months at both Petrusvlei and Speenkoppies. Basal areas and volumes were derived from these measurements. There were distinct family and provenance differences for growth at the different sites, with the Hanging Rock provenance generally performing well across all sites. A genotype × environment interaction was present between two sites, as indicated by low Type B correlations of 0.47 and 0.53 for basal area and volume, respectively. This indicated that different populations of E. cypellocarpa should be developed for the cold and warm sites.     

25年生大花序桉种源生长与形质性状的遗传变异及选择

[目的]研究广西国有东门林场25年生大花序桉种源生长与形质性状的遗传变异,筛选优良种源及单株,为大花序桉良种繁育及中大径材培育提供优质遗传材料。[方法]采用方差分析、构建性状选择指数方程综合分析等方法,对11个大花序桉种源进行生长与形质性状遗传变异分析及选择。[结果]表明:大花序桉胸径(DBH)、树高(H)、单株材积(V)、树干通直度(ST)和树干圆满度(SF)在种源间呈极显著差异;上述5个主要性状的种源遗传力(H2)为0.634 0.895,单株遗传力(h2)为0.136 0.342;以DBH、H、V、ST和SF 5个性状指标构建大花序桉种源/单株选择指数方程,按标准选择出4个优良种源和13株优良单株,优良种源平均材积遗传增益达11.2%,优良单株平均材积遗传增益达29.7%,选择效果尚好。[结论]大花序桉5个主要性状遗传变异在种源水平受中度至较强遗传控制,在单株水平受弱度遗传控制。优良种源D47、S14127、B47和S12195生长材性兼优,可用作培育优质中大径材。     

Genetic control of wood density and bark thickness,and their correlations with diameter,in pure and hybrid populations of Eucalyptus grandis and E. urophylla in South Africa

Tree diameter under and over bark at breast height (dbh), wood density and bark thickness were assessed on samples from control-pollinated families of Eucalyptus grandis, E. urophylla, E. grandis × E. urophylla and E. urophylla × E. grandis. The material was planted in field trials in the coastal Zululand region of South Africa. At 75 months, between three and seven of the best trees per family were felled and wood samples collected. Genetic parameters for wood density, bark thickness and bark percentage (ratio of double bark thickness to overbark diameter) and the inter-trait correlations for the different species and hybrids were calculated. Genetic parameter estimates for wood density, bark thickness and bark percentage in the E. urophylla × E. grandis hybrids showed these traits to be under total additive genetic control. This was confirmed by the intermediate hybrid means for these traits relative to those of the parental species. There was a very low correlation between dbh and wood density for the E. urophylla × E. grandis hybrids (r_G = –0.07 and r_P = 0.064). Amongst the E. urophylla families there was a moderate positive and significant phenotypic correlation between wood density and bark thickness (r_P = 0.391), and between wood density and bark percentage (r_P = 0.442).     

Estimates of genetic parameters and genetic gains for growth traits of two Eucalyptus urophylla populations in Zululand,South Africa

In South Africa, Eucalyptus urophylla is an important species due to its disease tolerance to fungal diseases such as Crysoporthe austroafricana and the Coniothyrium sp. cankers. It is mainly planted as a parental species in a hybrid combination with E. grandis. Generally, the E. grandis × E. urophylla hybrid has better disease tolerance and higher wood density than pure E. grandis. The current strategy is to maintain large breeding populations of both parental species in order to provide improved elite selections for hybrid crosses on a regular basis. With this in mind, two E. urophylla populations, consisting of five provenance/progeny trials, were established in the subtropical region of Zululand. The aims of this study were, firstly, to determine the magnitude of genotype × environment interaction of E. urophylla in Zululand; secondly, to estimate genetic parameters and correlations for diameter at breast height (DBH), height and volume; and thirdly, to identify selections to advance the current breeding population as well as to hybridise with E. grandis. Results indicated that genotype × environment interaction effects would be practically negligible for growth in Zululand and therefore a single breeding population will be appropriate. In general, all growth traits were under low to moderate genetic control, with narrow-sense heritabilities ranging between 0.14 and 0.48 for volume. The genetic correlations between growth traits were high (0.98 and 0.99 for DBH– volume). This is an indication that DBH is a sufficient growth measure to use in E. urophylla breeding programmes. Best linear unbiased prediction estimates indicated that aa selection scenario of 200 individuals will generate genetic gains of 44.7% over the population mean. The estimated gains for the top 50 individuals that could potentially be used as hybrid parents to cross with E. grandis was 59.8% over the population mean.     

广西丘陵台地巨尾桉、尾叶桉(实生)地位指数表的编制*

从广西南部桉树主要栽培区丘陵台地立地类型现有林人中收集的９５株解析木及９１株固定标准地内平均优势木调查材料，选用ＬｎＹ＝Ａ＋Ｂ×Ｘ＾ｃ公式模拟出巨尾桉和尾叶桉的导向曲线。最后确定了广西丘陵台地两种桉树的立地指数表。经检验，达到了较高的估测精度。     

广西东门林场桉树无性系选育研究概述

对东门林场多年来所做的桉树无性系选育研究进展以及结果进行了总结分析。通过大量桉树树种(种源、家系)的引进,在优良种源、林分及优良单株选择的基础上,进行杂交育种和子代测定,开展优树选择和无性繁殖,开发出优良无性系,并通过无性系对比试验和区域试验,最终选育出优良无性系进行推广造林。东门林场先后选育出1800多个桉树优良无性系,其中已有140多个在林业生产中广泛推广和应用,树立了东门的“DH”(东门杂交种)品牌形象,充分展示东门林场的资源优势和技术优势,为我国的桉树无性系事业发展做出了贡献。     

Dissimilar stem and leaf hydraulic traits suggest varying drought tolerance among co-occurring Eucalyptus grandis × E. urophylla clones

In South Africa, there is currently a phenomenon where a Eucalyptus grandis × E. urophylla clone is dying on a large scale, whereas co-occurring clones in the same plantation area remain healthy. No primary biotic pathogen has been isolated from these dying trees. However, the plantation region has endured severe drought conditions. We hypothesised that the specific E. grandis × E. urophylla clone dieback is due in part to the affected trees having an elevated drought vulnerability. We tested this hypothesis retrospectively by examining how the dying (branch dieback started) as compared with two healthy and co-occurring E. grandis × E. urophylla clones vary in branch xylem anatomy (water transport) and leaf stable carbon isotopes (gas exchange) across two levels of mean annual precipitation in the planted landscape. There was significant intra-hybrid variation in the range of studied hydraulic traits. It appeared that the dying clone is maladapted to drier field conditions relative to the two healthy growing clones. Individuals of the drought-susceptible clone had increased hydraulic conductivity, having both wider vessel lumens and larger lumen fractions, and also did not regulate leaf-level transpiration in the drier landscape as efficiently as the two unaffected clones (lower δ¹³C ratios). In turn, one of the healthy growing clones had a completely different hydraulic strategy, having higher wood density, lower lumen fractions, and higher δ¹³C ratios that are widely considered as hydraulically resilient during water stress. The other clone appeared to also gain drought tolerance via higher leaf-level water-use efficiency, although drought tolerance was less clear regarding xylem anatomy. We highlight how variation in relative drought vulnerability can be highly significant even between clones within a single hybrid group. Knowledge of this variation in plant hydraulics between commercially planted and closely related Eucalyptus trees would complement clone deployment programmes in a target landscape.     

西南桦和尾巨桉凋落叶分解及其与土壤性质的相关性

[目的]探讨南亚热带西南桦和尾巨桉人工纯林的凋落叶分解动态及其与土壤化学性质之间的相关关系.[方法]采用原位分解袋法研究凋落叶的分解过程.[结果]表明:西南桦、尾巨桉人工林凋落叶分解系数分别为0.96 a^-1和0.88 a^-1.在为期12个月的分解试验中,2种凋落叶有机C含量在整个分解过程中呈逐渐下降趋势;全K含量和C/N比在分解前期迅速下降,之后趋于平缓;全N含量和全P含量在整个分解过程中呈逐渐上升趋势;2种凋落叶N/P比则呈先升高后下降的趋势.无论是分解前期还是分解后期,凋落叶质量损失与N含量均呈显著正相关(前期R=0.877;后期R=0.855),与C/N均呈显著负相关(前期R=-0.735;后期R=-0.697).与尾巨桉林地土壤性质相比,西南桦凋落叶分解提高了林地0~10、10~20 cm土壤的有机C、全N、全P、全K、N/P,对2030 cm土壤有机C、全K、pH值、C/N、N/P则未产生显著影响.相关分析表明:凋落叶初始有机C含量与土壤有机C、全N、全P、全K、N/P显著相关;凋落叶初始全N含量与土壤全N、pH值、C/N显著相关.[结论]凋落叶的养分含量与土壤养分的关系紧密;与尾巨桉相比,西南桦凋落叶的养分含量明显较高,分解速率更快,释放到土壤中的养分也更多.     

Genetic variability of growth and wood chemical properties in a clonal population of Eucalyptus urophylla × Eucalyptus grandis in the Congo

Thirty-four Eucalyptus urophylla × Eucalyptus grandis hybrids were evaluated with a view to selecting for improved growth and wood-quality traits for plantations in the Congo. Height, circumference at breast height and volume were measured at 12, 27, 37, 49 and 60 months. Lignin content, the syringyl/guaiacyl ratio and total extractives content were predicted by near-infrared spectroscopy using wood powder samples collected from trees at breast height. While wood chemical properties were stable and under strong genetic control, growth traits were not. The genetic correlation between lignin content and growth was weak and negative, whereas the environmental correlation was also weak but positive. The genetic improvement of E. urophylla × E. grandis clones, based on growth features, leads to a limited decrease in lignin content and syringyl content and to a limited increase in extractives content.