Species diversity in Eucalyptus camaldulensis woodlots and miombo woodland in Northeastern Zimbabwe

The tree species diversity, groundvegetation species richness, and soilcharacteristics were studied forEucalyptus camaldulensis woodlots and thenatural miombo woodlands in the Mukarakate Areaof Northeastern Zimbabwe. The woodlandcharacteristics were measured and soil sampleswere taken at a total of thirty-four miombowoodland plots and twenty-seven eucalyptusplantations.The number of tree species was significantlyhigher for the miombo woodland sites than forthe eucalyptus woodlots. The Berger-Parker andShannon-Wiener Index values for speciesdiversity were higher for the tree speciesfound on the miombo woodland sites. There wereno significant differences between theeucalyptus woodlots and the miombo woodlands inthe percentage of grass cover and the number ofgrass and herb species. The same grass and herbspecies were common in both the woodlots andthe woodlands. The older woodlots hadsignificantly more tree and herb species thanthe younger woodlots.Soil nutrient analyses showed no significantdifferences between the woodlots and thewoodlands regarding their available phosphorusand total nitrogen, but the total phosphorusand total carbon were higher for the miombowoodlands. The results suggest that E.camaldulensis woodlots established in areasthat were formerly fields and grazing areas inthe savannah-like conditions pertaining inSouthern Africa do not cause the loss ofspecies richness or soil nutrients. In heavilydeforested areas eucalyptus woodlots may evencontribute positively to the protection andpreservation of indigenous trees species andother flora.     

Genetic characterisation of a Eucalyptus nitens base breeding population in South Africa

The measurement and statistical analysis of data from eight Eucalyptus nitens trials, established in the summer rainfall forestry region of South Africa during the 1980s and 1990s, have enabled the characterisation of the Institute for Commercial Forestry Research's breeding population. Provenance testing showed that the more northerly New South Wales (Australia) Eucalyptus nitens provenances of Barren Mountain and Barrington Tops are distinctly better suited to the summer rainfall areas of South Africa than the southern New South Wales provenances and the Victorian provenance, Penny Saddle. Generally, the species was not badly affected by Coniothyrium canker. High type B genetic correlations for all site pairs, except one comparison, ranged from 0.75 to 0.99 for diameter at breast height (dbh), indicating very little or no genotype × environment interaction for dbh for the genotypes tested in this study. Narrow-sense heritability coefficients ranged from 0.01 to 0.34, indicating that the species generally exhibited sufficient breeding opportunity for improvement of diameter growth. High genetic correlations of greater than 0.90 between diameter measurements at 52 to 62 months after establishment and diameter measurements at 94 or 113 months were found, indicating that selections can be reliably made at five or six years. Predicted genetic gains were highest in the trials at Goedehoop and Arthur's Seat, with increases in dbh of 3.07 cm (17.1%) and 3.17 cm (20.7%), respectively, at full rotation.     

Effect of NaCl and high pH on seedling growth of 15 Eucalyptus camaldulensis Dehnh. provenances

Eucalyptus camaldulensis Dehnh. is a moderately salt-tolerant Australian tree species widely used in farm forestry, often in salt-affected landscapes. In a glasshouse experiment, E. camaldulensis seedlings from 15 wide-ranging Australian seed sources (provenances), were cultured in sand-filled pots and treated for 57 days with control (no added NaCl in tap water, neutral pH), saline (150 mol m^–3 NaCl, stepped high pH (pH 7.6 to 9.5) and combined NaCl and high pH solutions. Significant differences were found among provenances in height and shoot dry weight. Differences in provenance response to treatment were found for dry weight but not for height. Reductions in shoot dry weight due to NaCl and high pH ranged from 42.9% to 82.0% and 4.3% to 51.7% respectively. Provenances from Lake Hindmarsh-SE (Victoria) and Lake Albacutya-N (Victoria) had relatively high tolerance to both stresses whereas those from Lake Albacutya-S (Victoria), Lowan Valley (Victoria), Silverton (New South Wales) and Katherine (Northern Territory) had low tolerance to both stresses. Provenances from De Grey River and Fitzroy River (Western Australia) were most tolerant of high pH. The performance of these provenances in this experiment generally accorded well with that in saline field environments.     

Tropical red gums — a source of 1,8-cineole-rich Eucalyptus oil

Tropical provenances of Eucalyptus camaldulensis Dehnh. and E. tereticornis Smith were studied, in their natural habitat in Australia and in a 3.75-year-old progeny trial in Zimbabwe, for their potential to produce medicinal-grade essential oils. Substantial interand intra-specific variation in the contents of five prominent monoterpenes, 1,8-cineole, -pinene, -pinene, limonene and p-cymene was found. Plantations of E. camaldulensis established in the wet/dry tropics using seed from Petford in northern Queensland offer immediate potential for oil production. Other widely-planted Queensland provenances with oil potential are Gilbert River Bridge E. camaldulensis and, after some genetic improvement, E. tereticonis from Morehead and Kennedy Rivers. Select individual trees at Petford provide oil of enhanced quality, at about double the yield of average trees.     

Structural conversion of the lignin subunit at the cinnamyl alcohol stage in Eucalyptus camaldulensis

The lignin biosynthetic pathway in Eucalyptus camaldulensis was investigated by feeding stems with deuterium-labeled precursor. Pentadeutero[,-D₂ OCD₃] coniferyl alcohol was synthesized and supplied to shoots of E. camaldulensis, and incorporation of the labeled precursor into lignin was traced by gas chromatography-mass spectrometry. In addition to the direct incorporation of labeled precursor into the guaiacyl unit, a pentadeuterium-labeled syringyl unit was detected. This finding indicates that the -deuterium atoms in the hydroxymethyl group of labeled coniferyl alcohol remain intact during modification of the aromatic ring. The relative level of trideuterium-labeled syringyl monomer (the result of conversion via the cinnamic acid pathway) was negligible, suggesting that the pathway at the monolignol stage is used for conversion of exogenously supplied precursor. Our results provide conclusive evidence of a novel alternative pathway for generation of lignin subunits at the monolignol stage even in plants that do not accumulate coniferin in lignifying tissues.     

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantations by near infrared spectroscopy for improving wood selection for high quality pulp

Near-infrared (NIR) spectroscopy has been demonstrated as a means for rapid nondestructive determination of the chemical composition and final pulp yield of Eucalyptus camaldulensis in Thailand tree plantations. Multiple linear regression (MLR) analysis and partial least squares (PLS) analysis were introduced to develop statistical models in terms of calibration equations for total pulp yield, screened pulp yield, and contents of -cellulose, pentosans, and lignin in wood. In MLR analysis, a reasonably good calibration equation was found only for pentosans (standard error of prediction (SEP): 0.98%). The PLS analysis improved the accuracy of prediction for every criterion variable, especially for pentosans (SEP: 0.91%) and lignin (SEP: 0.52%). Also, in the case of screened pulp yield, we were able to use such a statistical result as an indicator of the characteristics of the pulp and paper. Thus, NIR spectroscopy could be satisfactorily used as an effective assessment technique for Eucalyptus camaldulensis plantation trees.     

Influence of non-genetic factors on yield of monoterpenes in leaf oils of Eucalyptus camaldulensis

Sources of variation in yields (as a fraction of leaf weight) of 1,8-cineole, -pinene, -pinene and limonene in the leaf oils of young Petford Eucalyptus camaldulensis trees were studied. The oil yields of leaves up to 5 months of age were significantly affected by physiological changes associated with leaf maturation. The extent of these changes depends on genotype and on external influences such as soil moisture conditions. Prolonged drought stress reduced oil production in young leaves but did not affect greatly the equilibrium reached between synthesis and removal of oils at leaf maturity. Waterlogging prolonged peak oil production.Trends in oil yields with time differed markedly between individual trees. Although genotypic variation was great, there was detectable variation attributable to site, season and year. A relationship between seasonal patterns and climatic factors could not be established. Part of the observed variation in oil yields with time was attributable to variability in leaf maturity.The relative superiority in oil-yielding capacity of certain individuals in each experiment was maintained throughout, despite substantial variation from non-genetic sources. This consistency in ranking is of advantage to tree breeders wishing to make selections amongst plantations of differing age, on different sites and at different times of the year. However, even with careful sampling controls, absolute values will vary substantially and progeny testing will be necessary to further assess the potential of the initial selections.     

Antioxidative and antiradical activities of <Emphasis Type="Italic">Eucalyptus camaldulensis</Emphasis> leaf oils from Thailand

The leaf essential oils (six samples) from three clones of Eucalyptus camaldulensis Dehnh. were characterized by gas chromatography-mass spectrometry. Radical scavenging and antioxidant properties were investigated by the 1,1-diphenyl-2-picylhydrazyl (DPPH) assay and the β-carotene bleaching test. It was found that the whole essential oil and its fractions had significant antioxidant effects when they were tested by each method. In the DPPH assay, the E. camaldulensis leaf oils showed IC₅₀ inhibitory concentrations in the range of 1.75–12.62 mg/ml. In the β-carotene bleaching test, the IC₅₀ valued were in the range of 14.30–118.55 μg/ml. Part of this report was presented at the 18th meeting of the Chugoku-Shikoku Branch of the Japan Wood Research Society, November 2006     

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.     

Eucalyptus plantations in Israel: an assessment of economic and environmental viability

This paper discusses a plantation management approach involving a combination of “short” and “long” rotations designed to allow farmers to receive income from trees as soon as possible after establishment. We present results from two plots that represent extreme conditions: (a) a seasonally waterlogged, non-saline site (Nahalal), and (b) a saline site (Ginnegar) located in the Yizre’el Valley, Israel. Six improved seed sources, four of Eucalyptus camaldulensis and two of E. occidentalis, were examined. The local Israeli seed source of E. camaldulensis (HA) performed best at both sites. In Nahalal, the short rotation thinning of the slower growing (50%) plantation trees could provide economic returns approximately five years after establishment. The calculated mean annual increment (MAI) of these trees reached 12.2 t ha⁻¹ year⁻¹. The long rotation, or better performing half of the plantation trees, could be used as a source of sawn timber, providing higher-value products. By nine years after establishment, the average DBH of the various seed sources reached 25.8 ± 1.9 cm. The calculated MAI of the combined cutting rotations reached 48.3 t ha⁻¹ year⁻¹. Eucalyptus grown under the combined (short- and long-term) management approach at Nahalal was more profitable than many other non-irrigated local crops. Eucalyptus production in Ginnegar would be less profitable than in Nahalal. However, an additional ecological benefit was provided by the crop’s ability to lower the water table. When this contribution to regional drainage is taken into account, trees become economically competitive with other non-irrigated field crops under saline conditions. Jim Morris–Deceased.     

尾叶桉与赤桉正反析因交配杂种F_1材性遗传参数的估算

[目的]通过尾叶桉与赤桉杂种F1材质性状的遗传参数估算及其分析,为桉树杂交育种材性改良亲本选配和交配设计提供理论依据。[方法]以尾叶桉与赤桉6×6正反析因交配杂种F1测定林为材料,并以相应亲本自由授粉的半同胞子代作对照。9年生时,对各小区的杂种和家系(5株小区,6次重复)选取2株平均木,在胸高1. 3 m处沿南北向钻取木芯,共984个,测定木材基本密度、纤维长、纤维宽和纤维长宽比,利用ASReml-R估算4个材质指标的特殊配合力、杂种优势、父母本单株狭义遗传力、遗传相关和表型相关系数。[结果]表明:尾叶桉与赤桉正反交的杂种木材基本密度优于对照,呈明显的杂种优势;反交组合杂种其木材基本密度优于正交组合杂种,正交组合杂种的纤维特性优于反交组合的;在正交组合杂种中,木材基本密度、纤维长和纤维长宽比的母本效应低于父本效应;而反交组合杂种中,4个材质指标的母本效应均高于父本效应。木材基本密度和纤维特性指标受中至低遗传控制。正反交组合杂种中,除纤维长宽比外,其余3个材质指标的显性效应大于加性效应。对于遗传相关,杂种的木材基本密度与纤维宽呈极显著的负相关,与纤维长宽比呈极显著的正相关,与纤维长呈不显著负相关,纤维长与纤维宽呈显著正相关。对于表型相关,除纤维宽与纤维长宽比呈不显著正相关外,其余性状间均呈极显著正相关。[结论]尾叶桉与赤桉杂种的材质性状遗传差异因亲本和交配方式而异,表明通过种间杂交和正向选择进行材质性状的遗传改良具有潜力。     

Optimum age for selection based on a time trend of genetic parameters related to diameter growth in seedling seed orchards of Eucalyptus pellita in Indonesia

The time trend of genetic parameters related to diameter growth was investigated using data at ages from 1 to 6 years to determine the optimum age for selection in four seedling seed orchards of Eucalyptus pellita in South Kalimantan and Riau (Sumatra), Indonesia. The seed orchards at each location were from three geographically distinct provenances from Papua New Guinea. The pooled sum of squares and sum of cross products derived from an analysis of variance of growth of the three provenance populations were used to estimate genetic parameters at each location. Because the genetic parameters at rotation age, 8 years in this study, were not available, they were estimated using functions derived from their time trends. Phenotypic variances and genetic variances calculated at each age were converted to the corresponding square roots, and then analyzed by the linear regression using means as independent variables. The trend of juvenile–mature correlation was fitted by a modified Richards function with the ratio of the older diameter mean to the juvenile diameter as an independent variable. Early selection always resulted in more genetic gain per year than selection at rotation age, and the optimum age for selection, where genetic gain per year was maximized, was found to be 4 and 5 years in the two locations.     

Determining the climatic suitability of Eucalyptus dunnii for plantations in Australia,China and Central and South America

Climatic conditions within the naturaldistribution of Eucalyptus dunnii were determinedusing interpolated relationships developed forAustralia. Climatic interpolation relationships forAfrica, Central and South America and China as well asAustralia were then used to examine locations where E.dunnii has been successfully grown in trials and todetermine the species' climatic adaptability outsideits natural range. The original climatic profile wasrevised and maps were produced to show climaticallysuitable regions in Australia, China and Central andSouth America.     

Allelopathic effects of essential oil from Eucalyptus grandis × E. urophylla on pathogenic fungi and pest insects

This study on the allelopathic effects and chemical components of the essential oi l from Eucalyptus grandis × E. urophylla shows that the leaf oil emulsion of E. grandis × E. urophylla can inhibit the proliferation of pathogenic fungi Fusarium oxysporum, Pyriculerie grisea, Glorosprium musa rum and Phytophthora capsici. Pupation and feeding of the pest insects Spodopteralitura Fabricius and Helicoverpa armigera Hubner are shown to be affected with restraining effects which increase with the increasing levels of oil concentration. A GC/MS analysis of the leaf oil indicated that the main components, with a relative content of ⩾3%, were alloocimene (43.22%), α-pinene (13.63%), γ-terpinene (5.49%), (E)-3,7-dimethyl-2,6-octadien-1-ol (3.58%), β-fenchyl alcohol (4.58%), and 2-amino-3,5-dicyano-6-(4-methoxyphenoxy)-pyridine (3.67%). Terpenes played an important role in the inhibitory effects of E. grandis × E. urophylla essential oil on pathogenic fungi and pest insects. Poor biodiversity of eucalyptus plantations is a function of allelopathy. __________ Translated from Chinese Journal of Ecology, 2007, 26(6): 835–839 [译自: 生态学杂志]     

Species and site selection for timber production on farm boundaries in the humid Atlantic Lowlands of Costa Rica and Panama

In 1987–89 the CATIE-GTZ Agroforestry Project set up experiments with five timber tree species planted in single lines on twelve farm boundaries in cooperation with local farmers. When the trees were five years old, their height, diameter and total stem volume were: Acacia mangium 17 m, 19 cm and 67 m³ km^–1, Cordia alliodora 14 m, 20 cm and 46 m³ km^–1, Eucalyptus deglupta 22 m, 24 cm and 85 m³ km^–1, Tectona grandis 17 m, 20 m and 64 m³ km^–1, Terminalia ivorensis 18 m, 23 cm and 104 m³ km^–1. Considering these excellent growth rates, planting of Cordia alliodora, Eucalyptus deglupta and Tectona grandis in lines on farm boundaries should be promoted. T. ivorensis and A. mangium are not recommendable for sites with impeded drainage because of mortality caused by root rot, mostly due to Rosellinia sp.     

Provenance and family variability in slash pine (Pinus elliottii var. elliottii Engelm.) grown in southern Brazil and northeastern Argentina

A total of 172 seed orchard open-pollinated families of slash pine (Pinus elliottii var. elliottii Engelm.), generallysuperior for growth in the southeastern United States, wereevaluated in southern Brazil and northeastern Argentina. Mostfamilies were from selections originally made in four majorphysiographic regions within the species' natural distribution:Atlantic Coastal Flatwoods, East-Central Florida Flatwoods, GulfCoastal Flatwoods, and Southern Coastal Plain (withoutflatwoods). Ninety-one families were established in 1982 inthree tests in the Brazilian states of Santa Catarina and Parana. In 1986, 119 families, including 35 common to the Braziliantests, were planted in four tests in Corrientes and Misionesstates in Argentina. Variation among provenances for individualvolume growth was significant for both countries withEast-Central Florida Flatwoods consistently having the highestmean age-eight year volume and Southern Coastal Plainconsistently the lowest. Heritabilities were 0.20 in Argentinaand 0.44 in Brazil with within country type B geneticcorrelations of 0.66 and 1.00 for age-eight individual volume,respectively. The between country type B genetic correlation was0.63. Type B genetic correlations between United States breedingvalues for age-fifteen volume and Argentinian and Brazilianbreeding values for age-eight volume were 0.10 and 0.15,respectively. Families were generally superior to local checksin both South American countries.     

Genetic diversity of Castanopsis acuminatissima (Bl.) A. DC. in northern Thailand and the selection of seed trees for forest restoration

Castanopsis acuminatissima (Bl.) A. DC. is one of a number of framework species which are being planted to restore seasonally dry tropical forests in northern Thailand. This study describes the level of microsatellite variation within and among three populations of this species in three National Parks in northern Thailand: Doi Suthep-Pui, Doi Inthanon and Jae Sawn, using published primers developed for Castanopsis cuspidata var. sieboldii Nakai. The five microsatellite loci employed in this study detected a total of 54 alleles (n = 72). The informativeness of the microsatellite loci varied from six to 18 alleles, with an average of 10.8 alleles found over all loci. The mean observed heterozygosities in the three populations showed no significant deviations from Hardy-Weinberg expectations. The vast majority of genetic diversity was contained within the populations, with no significant differentiation between them (F_ST = 0.006). Algorithms were designed to capture microsatellite diversity, and the rationale for using microsatellite markers to inform genetic conservation is discussed. The implications for seed collection of C. acuminatissima for forest restoration are also discussed.     

An efficient method for clonal propagation and in vitro establishment of softwood shoots from epicormic buds of teak (Tectona grandis L.)

Softwood shoots were produced from 40 cm long stem segments placed horizontally in flat trays containing sterilized sand under natural light or shade conditions for subsequent rooting and micropropagation studies in teak (Tectona grandis L.). Higher number of shoots (6.17) per log was produced under natural light as compared to shade conditions. Forcing was also better in natural light as compared to shade in terms of shoot length, number of nodes or leaves. For rooting, 2–4 cm long softwood shoots were excised and treated with either indole-3-butyric acid (IBA) or α-naphthyl acetic acid (NAA) at 0, 1000, 2000 or 3000 μmol·L^–1 each or with combinations (1000 + 1000, 2000 + 2000 or 3000 + 3000 μmol·L^–1) and then placed in flat trays containing autoclaved sand at 25 ± 2ºC in 16 h photoperiod at 35 µmol·m^–2·s^–1. After 28 days, softwood cuttings treated with IBA + NAA (3000 + 3000 μmol·L–1) had highest rooting percentage (89.3%) with 5.5 mean roots. Shoot apex and nodal explants of softwood cuttings were pretreated with 0.1% (w/v) ascorbic acid, boric acid, activated charcoal, citric acid, glutamine or polyvinylpolypyrollidone (PVP) for 24 h to remove phenolic compounds before surface disinfestation. Glutamine (Gl) and PVP were equally effective resulting in 60% establishment of shoot apices on MS medium supplemented with 10 μmol·L–1 6-benzylaminopurine (BAP) + 5 μmol·L–1 NAA. Using shoot apices, highest (42.80) number of multiple shoots with 54.33 mm shoot length were obtained on MS + BAP (8.8 μmol·L–1) + IBA (2 μmol·L–1) after 45 days. Shoots were successfully rooted and acclimatized to greenhouse