Effects of Mycosphaerella leaf disease on the spectral reflectance properties of juvenile Eucalyptus globulus foliage

Mycosphaerella leaf disease (MLD) can cause significant discoloration, necrosis and defoliation in commercial plantations of young Eucalyptus globulus. This study investigated the spectral reflectance changes that result in E. globulus foliage from Mycosphaerella infection. Spectral reflectance measurements were made on healthy and infected E. globulus foliage in the visible and near‐infrared wavelengths (400–1000 nm). Reflectance (R) at 760 nm produced the largest difference between the extremes of disease severity classes. The wavelength most sensitive to infection severity was R678 nm. Other sensitive wavelengths were located between 480 and 500 nm. The wavelengths near 708 and 550 nm appeared relatively insensitive to infection severity. The reflectance index best correlated to leaf infection was R678/R550 (r = 0.841, p < 0.0001). This index was used in a linear regression model for successfully predicting leaf infection levels from an independent data set (r = 0.95, p < 0.0001).     

Effect of Coriolus versicolor on physico-chemical properties of Eucalyptus globulus wood

Summary The purpose of this study was to determine the progressive changes in physical and chemical properties of Eucalyptus globulus wood under the action of a representative white rot fungus, Coriolus versicolor. Observations concerning the nature and relative effects on weight loss, hot water solubility, 1% sodium hydroxide solubility, Klason lignin, holocellulose, intrinsic viscosity and degree of polymerisation of holocellulose, pentosans, methoxyl value, neutral sugar composition and nitrobenzene oxidation products are discussed.The authors thank Dr. P. S. Rehill, the then Officer-in-Charge, Forest Pathology Branch, for valuable suggestions and providing facilities for decay experiments     

Quality of refiner groundwood pulp as related to handsheet properties and gross wood characteristics

Summary Pupl quality, in terms of a fiber shape factor S and a fiber length factor L, was determined for 96 pulps disk-refined from chips of varying characteristics. S was evaluated in terms of the Canadian Standard Freeness of the 48/100 fiber length fraction and is a parameter inversely proportional to specific surface. L is the percentage, by weight, of pulp retained on a 48-mesh screen and reflects the distribution by weight of fiber length in the whole pulp. S and L accounted for as much as 83 percent of the variation in handsheet properties. Properties were improved by using pulps displaying low values of S and relatively high values of L. Both S and L were related to specific refining energy and wood quality. S increased with increasing unextracted chip specific gravity and rings per inch of growth rate but decreased with increasing latewood content and refining energy. L decreased with increasing refining energy, rings per inch of growth rate, and unextracted chip specific gravity but increased with increasing latewood.

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Zusammenfassung Die Qualität von 96 verschiedenen Zellstoffarten, alle im Scheiben-Refiner aus Hackschnitzeln unterschiedlicher Art hergestellt, wurde mit Hilfe des Faser-Form-Faktors S und des Faser-Längen-Faktors L bestimmt. S wurde in Einheiten des Mahlgrades nach Canadian Standard Freeness der 48/100 Faser-Längen-Fraktion bestimmt. S ist als Parameter umgekehrt proportional zur spezifischen Oberfläche. L ist der gewichtsmäßig bestimmte Anteil an Zellstoff, der ein 48-Mesh-Sieb nicht mehr passiert und gibt gleichzeitig gewichtsmäßig die Verteilung der Faserlängen in der Gesamtmenge des Zellstoffes an. Durch S und L werden 83% der Eigenschaftsschwankungen innerhalb der Prüfblätter erklärt. Diese Eigenschaften konnten durch Zellstoff mit niedrigeren S-Werten und relativ hohen L-Werten verbessert werden. Sowohl S als auch L wurden mit der spezifischen Refiner-Leistung und mit der Holzqualität korreliert. S nahm mit ansteigender Dichte der unbehandelten Hackschnitzel und mit ansteigender Jahrringzahl je Zuwachseinheit zu, fiel dagegen mit ansteigendem Spätholzanteil und Refiner-Leistung ab. Dagegen nahm L mit ansteigender Refinerleistung, Jahrringzahl je Zuwachseinheit und Dichte der unbehandelten Hackschnitzel ab, stieg jedoch mit zunehmendem Spätholzanteil an.

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The author appreciatively acknowledges the assistance of Roy O. Martin Lumber Co., Alexandria, La.: R. A. Leask and J. Adams of Bauer Bros. Co., Springfield, Ohio; and D. Bower, mathematical statistician at the Southern Forest Experiment Station, New Orleans, La.     

Effects of ozone on growth and gas exchange of Eucalyptus globulus seedlings

To study the effects of a low concentration of ozone on growth and gas exchange in Eucalyptus globulus Labill. seedlings, ozone was applied for 37 days at a concentration of 50 ppb for 7 h daily under conditions of low light (250 micro mol m(-2) s(-1) (PAR)) and controlled temperature (20 degrees C). The seedlings exhibited extreme sensitivity to ozone. The ozone treatment reduced total plant biomass but had no effect on the partitioning of assimilate. Photosynthesis, stomatal conductance and internal CO(2) concentration were all reduced by ozone. The decline in photosynthesis was partly the result of direct effects of ozone on the stomata.     

Mycosphaerella species occurring on Eucalyptus globulus and Eucalyptus nitens plantations of Tasmania,Australia

The genus Mycosphaerella Johanson contains many pathogens capable of causing a severe impact on the growth of susceptible eucalypt species. The lack of knowledge about which species are present in Tasmania and their potential risk to the plantation industry prompted this study into the Mycosphaerella species occurring on Eucalyptus globulus and Eucalyptus nitens plantations in Tasmania. A total of 36 plantation and five road verge sites of E. globulus and E. nitens were sampled. Five Mycosphaerella species and three species from associated anamorph genera were isolated and identified in Tasmania; Mycosphaerella nubilosa, Mycosphaerella cryptica, Mycosphaerella tasmaniensis, Mycosphaerella grandis, Mycosphaerella vespa, Coniothyrium ovatum, Sonderhenia eucalypticola and Sonderhenia eucalyptorum. The most frequently isolated species with the highest incidence and severity of infection were M. cryptica and M. nubilosa. These two species appear to have the greatest potential to damage juvenile eucalypt plantations in Tasmania. A link between Mycosphaerella vespa and Coniothyrium ovatum is described for the first time.     

Effects of pulp freezing and frozen pulp storage on fibre characteristics

Summary A requirement of long-term research on pulp fibres in that the material for study be stored for prolonged periods without deterioration and without changes in properties. In this paper effects of pulp freezing and thawing and of frozen pulp storage on fibre, wet web, and handsheet properties are discussed. A variety of radiata pine kraft pulps, a radiata pine sodium bisulphite pulp, and silver beech and hard beech (Nothofagus species) kraft pulps are examined.The expanded walls and diameters of beaten fibres were contracted by pulp freezing. This behaviour made fibres less flexible and less able to collapse during papermaking operations. The freezing treatment also caused fibre kinks and other fibre configurations which existed in a pulp before freezing to be fixed into position and made somewhat resistant to straightening when in strained wet webs. It was found that extents of fibre kink can be varied depending on the degree to which fibre configurations are forced into a pulp network before freezing. Increasing periods of frozen storage caused the intensity and distribution of bonds redeveloped by the freezing treatment to be progressively modified. Fibre walls were, however, not contracted further by increasing periods of frozen storage.The technical assistance of Miss D. Brookes is gratefully acknowledged     

蓝桉组织培养的研究

用蓝桉（Ｅｕｃａｌｙｐｔｕｓｇｌｏｂｕｌｕｓ）离体芽器官诱导培养，分化形成丛生芽，年繁殖系数３￣（１２）。０．１～０．５ｍｇ／Ｌ的６－ＢＡ或０．５～０．８ｍｇ／Ｌ的ＫＴ诱导外植体（带节茎段）腋芽萌动的效果最佳，诱导率分别达８０．３％和８１．５％。１．５～２０ｍｇ／Ｌ的６～ＢＡ或２０～２．５ｍｇ／Ｌ的ＫＴ分别与０．５～１．０ｍｇ／Ｌ的ＮＡＡ组合，对于促进腋芽分化形成丛生芽及继代培养中芽的增殖具有最佳效果。培养基中的无机盐浓度、蔗糖含量对蓝桉试管苗的生根具有显著影响；ＩＢＡ促进蓝桉试管苗的生根。至目前为止，在１／２ＭＳ无机盐培养基＋ＩＢＡ１．２～１．４ｍｇ／Ｌ＋Ｓ５ｇ／Ｌ中诱导生根，生根率最高可达２６．４％。     

蓝桉、直干桉综合丰产技术试验示范

试验林采用正交设计，因素为树种、整地方式、密度、施肥，各因素取３个水平，３次重复。用生长量、生物量与投入产出进行评价。试验结果：３．５年生蓝桉、直干桉幼林最佳处理平均高９．５ｍ，平均胸径８．９ｃｍ，每ｈｍ２蓄积量７０．５１２６ｍ３，最佳处理比最差处理树高大２８．４％，胸径大３４．９％，蓄积量大１８３％。用已取得的技术成果营造的示范林，３．５年生平均高９．８ｍ，平均胸径６．５ｃｍ，累计产桉叶２．４３万ｋｇ／ｈｍ２，３年生左右，通过桉油及薪柴的收入可以回收全部造林及加工成本。     

Leaf orientation,light interception and stomatal conductance of Eucalyptus globulus ssp. globulus leaves

Juvenile and adult leaves of the heteroblastic species Eucalyptus globulus Labill. ssp. globulus did not show active diurnal orientation toward or away from incident radiation. Juvenile leaves of a late-maturing sapling of a Tasmanian provenance were evenly distributed in all azimuth sectors. In contrast, an early-maturing sapling of the same age from Wilsons Promontory, Victoria had a predominance of adult leaf blades facing east and west. Mid-vein and blade angles of juvenile and adult leaves were non-random with an overall vertical declination of the leaves. Both leaf types intercepted a greater irradiance during the morning than at midday. Sub-horizontal juvenile leaves intercepted 22% more irradiance than vertical adult leaves during the middle of the day. The amphistomatal and isobilateral adult leaves intercepted sunlight equally on both leaf surfaces. Stomatal conductance was variable during the period of measurement but was similar for the Tasmanian juvenile (0.4 to 0.9 cm s(-1)) leaves and Wilsons Promontory adult (0.5 to 1.2 cm s(-1)) leaves. Greater light interception by the sub-horizontal juvenile leaves would confer a growth advantage to saplings and regenerating canopies. Reduced light interception and leaf temperature of vertical adult E. globulus leaves would assist in water conservation, particularly at high solar angles.     

Studies on Dual Mycorrhizas of Eucalyptus globulus and E

This paper represents the first part of the results from a glasshouse experiment designed to compare the competition of ECM and VAM fungi on root colonization and effects on growth of two Eucalyptus species　（E．globulus and E．urophylla）．One ECM fungus（Laccaria lateritia）　and three VAM fungi belonging to genera Glomus，Acaulospora and Scutellospora，along with field soil as well，were used to inoculate Eucalyptus seedlings alone or in combination．Both ECM and VAM fungi colonized and formed mycorrhizal associations on roots of inoculated seedlings，though infective rates of VAM and ECM tips per meter varied according to inoculant fungi and plant ages． There were some regressive interactions for colonization between the two fungi，as a general trend for ECM root colonization levels to increase with time at the expense of VAM colonization was observed during 16 weeks． The effect of phosphorus levels in soils on mycorrhizal formation was discussed．     

蓝桉人工纯林土壤肥力研究

本项研究历时４年,研究结果显示,营造蓝桉纯林会引起林地土壤肥力明显降低,有机质、全Ｎ、有效Ｎ、Ｐ、Ｋ、交换性Ｃａ２＋、Ｍｇ２＋等７项指标均直接受影响。蓝桉人工林,经造林初期林地施肥能提高其生长量,但不能阻止林地土壤肥力下降。由于施肥促进了林木的生长,故也加强了对土壤肥力的消耗。     

Cellulose content as a selection trait in breeding for kraft pulp yield in Eucalyptus urophylla

? The aim of this study was to investigate the effectiveness of using cellulose content, measured by the diglyme-HCl method, as a selection trait in breeding programs for kraft pulp yield in Eucalyptus urophylla.

? A total of 275 trees from sixty-two families were sampled from a thinned progeny trial of E. urophylla in northern Vietnam to evaluate cellulose content from breast-height increment cores. Among those, twenty unrelated trees were felled to evaluate cellulose content and pulp yield from breast-height disk samples.

? The regression of pulp yield of disk samples on cellulose content was strong either from disks (R ² = 0.83) or increment cores (R ² = 0.69). There was no significant difference in cellulose content between the provenances. The narrow-sense within-provenance heritability of cellulose content was 0.50 and the coefficient of additive genetic variation was 3.9%. Genetic correlations between cellulose content and growth (0.28–0.45) or wood basic density (?0.02) were not significantly different from zero.

? Breast-height increment core cellulose content measured by diglyme-HCl method is under strong genetic control and can be used to rank trees for pulp yield in E. urophylla plantations. Selection for increased cellulose content would have only minor effects on growth and wood basic density.

     

Effects of site preparation and slash management on growth and understory vegetation of Eucalyptus globulus plantations along a rotation time span in Portugal

The removal or maintenance of harvest residues in eucalypt plantations may influence site quality and productivity. Removal of slash from the site may facilitate further management operations and provide a valuable energy resource, but effects on site productivity and sustainability for a rotation time span were not yet assessed under Mediterranean conditions. Therefore, a study was carried out to assess the effects of slash (harvest residues plus forest floor litter) management and soil preparation options on stand productivity and understory vegetation dynamics, hypothesizing that those options influence tree growth, forest floor dynamics and understory biomass and diversity. An experiment was installed in West Central Portugal, consisting on: removal of slash without soil preparation (R); broadcast of harvest residues on the soil surface without soil disturbance (S); as in S, but concentrating the woody debris between tree rows (W); incorporation of slash into the soil by harrowing (I); removal of slash followed by harrowing (RH); and as in I followed by ripping (IS). The experiment was monitored for a rotation time span (140 months). Maintenance of slash followed by deep soil disturbance led to the highest wood production, but differences between treatments were not significant (p > 0.05). Forest floor load and understory biomass were also similar between treatments. Ground vegetation played an important role on nutrient cycling in early rotation stages, such effect being irrespective on slash management options. Incorporation of slash into the soil followed by ripping is probably the best option to match production and environmental sustainability of eucalypt plantations in Mediterranean conditions.     

Nondestructive sampling of Eucalyptus globulus and E. nitens for wood properties. III. Predicted pulp yield using Near Infrared Reflectance Analysis

  Within-tree variation in kraft pulp yield, predicted using near infrared reflectance analysis, was studied in thirty trees of E. globulus and fifty trees of E. nitens to develop a non-destructive sampling strategy. Trees, aged 5 to 9 years, were sampled across a range of sites in southern Australia. Simulated core samples were removed at six fixed heights easily accessible from the ground (0.5, 0.7, ... 1.5 m) and at seven percentage heights (0, 20, 30, ... 70%). Whole-tree values, calculated from percentage height data, were correlated with the core data to determine the optimal sampling height. Core samples were found to be good predictors of whole-tree pulp yield for E. globulus, with simulated cores taken from the recommended sampling height (1.1 m) explaining more than 50% of variation in whole-tree pulp yield. Results for E. nitens were variable with large site differences apparent. On high quality sites, core samples from the recommended sampling height (0.9 m) were good predictors of whole-tree pulp yield, explaining around 60% of the variation. On poor quality sites, cores were poor predictors of whole-tree pulp yield. Radial orientation of cores was not important and predicted pulp yield was not related to tree size, basic density or fibre length. To estimate stand mean pulp yield to an accuracy of ±1% would require sampling 6 trees of E. globulus and 4 trees for E. nitens using either multiple discs or core samples. A single sampling height (1.1 m) is recommended for sampling for basic density, fibre length, fibre coarseness and predicted pulp yield in E. globulus. For E. nitens the recommended sampling height for basic density and fibre length is 0.7 m and 0.9 m is recommended for predicted pulp yield on good quality sites. Received 17 September 1998     

Development and application of a capillary electrophoresis method for the determination of ellagic acid in E. globulus wood and in filtrates from E. globulus kraft pulp

A capillary zone electrophoresis (CZE) method for simple and rapid determination of ellagic acid (EA) in Eucalyptus globulus wood and in the filtrate from unbleached kraft pulp has been developed. This is the first application of CZE for the detection of EA in industrial streams from cellulosic pulp production. The EA determinations in wood extractives and in pulp filtrates were succeeded only after sample acidification. This new CZE analytical procedure allowed reliable determinations of EA in E. globulus wood (1.1 ± 0.6 g kg^?1 of dry wood) and in the filtrates from unbleached kraft pulp (98 ± 0.7 mg L^?1). Gas chromatography–mass spectrometry was used as a reference method for the quantification of EA in industrial samples.     

High resolution temporal variation in wood properties in irrigated and nonirrigated Eucalyptus globulus

? Environmental determinants of wood properties variation were examined in Eucalyptus globulus, a globally important hardwood plantation species, in southern Tasmania, Australia.

? Radial variation in wood properties, measured with the SilviScan system, were re-scaled from distance to time abscissa using stem radial growth data measured with dendrometers. With this re-scaled data it was possible to evaluate how water availability and temperature affected wood density, microfibril angle (MFA) and fibre and vessel transverse dimensions in irrigated and non-irrigated trees.

? Wood density, fibre radial diameter and MFA were sensitive to water availability. Wood density increased and fibre radial diameter decreased in response to reduced water availability. When high water availability was maintained, wood density was negatively correlated with temperature. Together, temperature and soil matric potential explained about 60% of temporal variation in wood density variation. In contrast MFA was not related to temperature but decreased with increasing water stress. Slower growing trees also had lower MFA than faster growing trees. Slower growing trees had a larger number of vessels per unit area of wood than faster growing trees within this even aged stand. However, vessel radius to the 4th power was significantly higher in faster growing trees than in slower growing trees.

? Overall, E. globulus wood properties were sensitive to temporal changes in environmental conditions (particularly water availability) and associated growth rates. The data provided support for the hypothesis that growth rates are hydraulically mediated.

     

Physiology and anatomy of lenticel-like structures on leaves of Eucalyptus nitens and Eucalyptus globulus seedlings

Intumescences or abnormal, non-pathogenic, blister-like protuberant growths, form on Eucalyptus globulus Labill. and, to a much lesser extent, Eucalyptus nitens (Deane and Maiden) Maiden leaves when plants are grown in a high relative humidity environment. We examined the histology of intumescences and their effects on leaf photosynthetic processes. Intumescences were induced by placing E. globulus and E. nitens seedlings in a relative humidity of 80% in a greenhouse for 5 days. Symptomatic and asymptomatic leaves of plants with intumescence development were compared with leaves of control plants. Light-saturated carbon dioxide (CO(2)) assimilation (A(max)) and responses of CO(2) assimilation (A) to varying intercellular CO(2) partial pressure (C(i)) were measured. Symptomatic and asymptomatic leaf samples were fixed and sectioned and cellular structure was examined. Intumescences greatly reduced the photosynthetic capacity of E. globulus leaves and were associated with reduced electron transport rate and ribulose bisphosphate (RuBP) regeneration capacity. Tissue necrotization and cellular collapse of the palisade mesophyll and deposition of phenolic compounds in the affected areas, probably reduced light penetration to photosynthesizing cells as well as reducing the amount of photosynthesizing tissue. Photosynthetic capacity of E. nitens was unaffected. The intumescences resembled simple lenticels, both morphologically and developmentally. To our knowledge, this is the first time that lenticel-like structures developed in response to environmental conditions have been described on leaves.     

Development and variation of wood density, kraft pulp yield and fibre dimensions in young Norway spruce (Picea abies)

Important wood, pulp and fibre properties were investigated on small wood samples from two Rumanian, one German and one Norwegian provenance of Norway spruce (Picea abies) grown in Sørkedalen, Norway. Several samples were collected from inside each single tree, both in radial and transversal direction in the stem. Data were collected from a total of 59 trees, each 28 years of age. All investigated properties showed close relationship to ring number (RN) (cambium age). For basic density and fibre wall thickness (FWT), a fast decline was first observed when moving from pith to bark and a minimum value was found around RN 5–8. The declining trend was then followed by an increase. Kraft pulp yield, fibre length and fibre width (FW) also increased with RN, but the increase was most pronounced close to the pith. The pulp yield (PY) more or less stabilised outside of RN 5–6. FW showed a decrease outside of RN 10–12, but this was probably due to the remarkable simultaneous drop in ring width for the investigated trees. FW decreased, while basic density and fibre length increased with increasing height in the tree. PY and FWT were not affected by height in tree. Diameter at breast height (DBH) was the most important variable indicating differences between trees in the investigated material. Basic density, fibre length and FWT decreased, while FW increased with increasing DBH. Height to crown had a positive effect on basic density, but had no influence on any of the remaining properties. Differences between provenances were found for basic density, fibre length and FW. The analyses showed that it is possible to describe the variation inside and between trees satisfactorily for a range of important wood and fibre properties.     

Defoliation and nitrogen effects on photosynthesis and growth of Eucalyptus globulus

Plant responses to defoliation are complex. We established a field experiment in a nine-month-old Eucalyptus globulus Labill. plantation to examine the effects of pattern (upper crown versus lower crown removal), frequency (single, double or triple defoliation within a 12-month period) and severity (25 versus 38% of leaf area removed) of defoliation and the effect of soil nitrogen (N) on photosynthetic processes and stem growth. The photosynthetic responses observed following defoliation could be attributed to changes in source:sink ratios. Light-saturated CO(2) uptake (A(max)) increased with increasing severity and frequency of defoliation irrespective of defoliation pattern. Seedlings defoliated in autumn did not exhibit increases in A(max) until the following spring, whereas there was no such delay in photosynthetic responses associated with spring defoliation. Application of N before defoliation allowed trees to compensate for the effect of defoliation on stem diameter growth, which could not be explained simply in terms of increases in A(max). The observed increases in stem diameter increment following N fertilization of defoliated trees suggested increases in leaf area development, and there were changes in the leaf area:leaf dry mass ratio that may have increased light absorption by the crown. Nitrogen fertilization also increased partitioning of dry mass to branches at the expense of main stems, suggesting that N supply was important in rebuilding crowns following a defoliation event.     

蓝桉工业用材林的施肥效应及地力变化研究

蓝桉工业用材林的施肥效应及地力变化研究在云南保山和富民红壤地区进行,历经8年,结果表明施肥对蓝桉人工林有明显的增产效果,并且经济效益显著.P肥是蓝桉增产的主要因素,施用P肥的处理生长量明显高于其他处理;有机肥对蓝桉生长有一定的促进作用;N肥对蓝桉高生长的促进作用与K肥相近,对径生长的促进作用略低于K肥;在有效K含量较高的地区,可以不施用K肥.在云南红壤地区培育蓝桉短周期工业原料林,可根据林地土壤情况将施肥量控制为基肥施普钙或者钙镁磷肥400～500g*株-1;追肥施尿素50～100g*株-1、硫酸钾0～100g*株-1,分两年平均施入.据监测,施肥可以有效地阻止土壤养分含量迅速下降.