Elevated CO2 offsets the alteration of foliar chemicals(n-icosane,geranyl acetate,and elixene)induced by elevated O3 in three taxa of O3-tolerant eucalypts

Eucalypts are important forest resources in southwestern China,and may be tolerant to elevated ground-level ozone(O3)concentrations that can negatively affect plant growth.High CO2 may offset O3-induced effects by providing excess carbon to produce secondary metabolites or by inducing stomatal closure.Here,the effects of elevated CO2 and O3 on leaf secondary metabolites and other defense chemicals were studied by exposing seedlings of Eucalyptus globulus,E.grandis,and E.camaldulensis×E.deglupta to a factorial combination of two levels of O3(<10 nmol mol^(−1)and 60 nmol mol^(−1))and CO2(ambient:370μmol mol^(−1)and 600μmol mol^(−1))in open-top field chambers.GC-profiles of leaf extracts illustrated the effect of elevated O3 and the countering effect of high CO2 on compounds in leaf epicuticular wax and essential oils,i.e.,n-icosane,geranyl acetate and elixene,compounds known as a first-line defense against insect herbivores.n-Icosane may be involved in tolerance mechanisms of E.grandis and the hybrid,while geranyl acetate and elixene in the tolerance of E.globulus.Elevated O3 and CO2,singly or in combination,affected only leaf physiology but not biomass of various organs.Elevated CO2 impacted several leaf traits,including stomatal conductance,leaf mass per area,carbon,lignin,n-icosane,geranyl acetate and elixene.Limited effects of elevated O3 on leaf physiology(nitrogen,n-icosane,geranyl acetate,elixene)were commonly offset by elevated CO2.We conclude that E.globulus,E.grandis and the hybrid were tolerant to these O3 and CO2 treatments,and n-icosane,geranyl acetate and elixene may be major players in tolerance mechanisms of the tested species.

Solid Wood Products from Eucalypts Plantations

To improve and diversify the use of tropical plantation timbers in Southern China, with support from International Tropical Timber Organizations (ITTO), a research project was started in 2002 focusing on development of processing and manufacturing technologies to promote production of value-added wood products from eucalypts plantations. This project will also facilitate the formulation of forest management strategy in China to supplement the diminishing supply of timber from the natural forests. The sp...

Sound absorption property of wood for five eucalypt species

The sound absorption coefficients of wood and wood boards for five eucalypt species (Eucalyptus urophylla, Euca-lyptus urophylla E. grandis, Eucalyptus urophylla E. tereticornis, Eucalyptus urophylla E. camaldulensis and Eucalyptus cloeziana) that were collected from plantation in Dongmen Forestry Center of Guangxi Province, China were tested with stand-ing wave method and their sound absorption properties were also compared. The results showed that the sound absorption co-efficients of the five eucalypt wood species did not change evidently below 1000 Hz, but above 1000 Hz their sound absorption coefficients increased with the increasing frequency. The difference in sound absorption coefficient among five species of eucalypt wood is not evident at the tested frequency range (200-2000 Hz), but the sound absorption property of Eucalyptus urophylla at low frequency is better than that of other four species. The sound absorption coefficient of the tangential-sawn board is higher than that of the radial-sawn board. The sound absorption property of eucalypt wood of 0.5 cm in thickness is much better than that of 1.0 cm in thickness. It is concluded that wood sound absorption properties of eucalypts are affected by their board thickness and the type of sawn timber within the testing frequency, but the variance of wood sound absorption property among the five tested species is not significant.

Longitudinal growth strains in five clones of Eucalyptus tereticornis Sm

We studied the variability in longitudinal growth strains and wood basic density in five-year old trees from five clones （one tree per clone） of Eucalyptus tereticornis. Mean longitudinal growth strain in clones ranged from 466 to 876 μm. There was a significant difference between clones in growth strains and wood basic density. Clone 10 exhibited maximum growth strains and basic density, whereas clone 3 and clone 7 exhibited minimum growth strains and basic density, respectively. Within a tree, the growth strain variation with tree height was high but statistically insignificant while within tree variation in basic density was very small. There was no specific trend in variation in either strain or density within a tree. There was 5% 200% difference in growth strain on opposite sides of the logs. However two strains showed a strong positive correlation. There was a moderate positive association of wood basic density and mean growth strains in logs. The variation around the periphery emphasize the need to measure strain more than one, preferably on opposite sides at the same height, on a tree to know the mean strain level for the purpose of selection of clones.

Decline of eucalypt trees in tablelands of New South Wales, Australia

Eucalyptus species are the native and major plant group in Australian landscapes. Since European settlement, eucalypt trees heavily decline in the tablelands .of New South Wales. Tree recruitment bog down and the landscape ecosystem hardly recovers to the original state. This paper introduces the history of eucalypt trees and native shrubs decline, analyzes reasons of seedling recruitment decrease in this region, such as clearing, grazing, fire, competition from exotic species, dieback, insects, drought and so on, and summarizes the probable conditions of eucalypt tree recruitment, such as suitable conditions of seedling survival, sufficient seed supply, keep from predation, suitable germination conditions, non-grazed environment, mechanical treatment, weed control, fire regime, disease control etc, lending suggests how to preserve and encourage eucalypt trees recruitment in the area.

Age trends and correlations of growth and wood properties in clone of Eucalyptus urophylla × E. grandis in Guangdong, China

We assessed growth traits and wood properties ofDH32-29, a clone of Eucalyptus urophylla x E. grandis, at age of two to six years in Guangdong in China. Analysis of variance of studied traits showed that there were significant differences （1% level） on all studied traits among ages except for wood basic density. Analysis of age trends of growth traits and wood properties revealed that rotation length of DH32-29 should be more than six years or longer. Phenotypic correlations among traits at individual ages indicated that correlations between growth traits were strongly positive. There was significant change in relationship between growth and wood basic density with increasing age, ranging from -0.03 to -0.54 at 2 and 5 year and 0.003 to 0.3 at 3, 4 and 6 year. Correlations between Pilodyn pin penetration and basic density measured on increment cores showed that Pilodyn could rank or group genotypes or sites into density classes, but failure to predict individual tree and individual clone.

Growth rates of Eucalyptus and other Australian native tree species derived from seven decades of growth monitoring

There is widespread interest in estimating and forecasting individual tree and forest growth rates for restoration and carbon sequestration objectives. Outside intensively managed forests, past attempts have been limited by the lack of accurate long-term monitoring in multi-age mixed native forests to provide estimates of both expected mean diameter increments and the statistical variation in those estimates. A dataset from Eucalyptus-dominated native forests in subtropical Queensland, Australia offers an opportunity to provide accurate estimates of tree and forest growth rates. Over 86,400 trees from 155 native species were identified and remeasured between 1936 and 2011 in 641 permanent sample plots across a 500-2000 mm mean annual rainfall gradient. Individual tree diameter at breast height （DBH） increments observed for all species ranged mainly from 0.01 to 0.5 cm yr-1 （94 % of values）, with consistentdifferences between rainfall zones （mean of 500- 2000 mm yr-1）, and varying differences between species （155） and stem diameter class （10-100 cm）. For some spe- cies, diameter increment increased progressively with rain- fall （e.g. Eucalyptus siderophloia, Eucalyptus propinqua, and Lophostemon confertus）, but in others （e.g. Corymbia citriodora subsp, variegata, Corymbia intermedia, and Eucalyptus biturbinata） the greatest diameter increments were recorded between 1200 and 1600 mm yr-1. Where there were sufficient data, most species exhibited a quadratic relationship between DBH increment and DBH class, but two species （ Callitris glaucophylla and Eucalyptus crebra） native to the 500-800 mm annual rainfall zone showed lin- ear increases in DBH increment with increasing DBH. Continued monitoring of these plots would add to their already great value.

Age Trends and Correlations of Fiber Traits in Clone of Eucalyptus Urophylla×E.Grandis in Guangdong Province

Growth traits and wood properties were assessed for DH32-29,a clone of Eucalyptus urophylla×E.grandis,at the age of two to six in Guangdong,China.Analysis of variance of studied traits showed that there were significant differences(1%level)on Fiber Length and Fiber Width among ages,with F value ranging from 12.73 to 18.91,indicating clear differences between ages.The Fiber Length increased from 0.58 mm at 2-year to 0.60 mm at 3-year,061 mm at 4-year,0.72 mm at 5-year and 0.79 mm at 6-year,meanwhile the annual Fiber Length increment among ages increased from 0.02 to 0.01,0.11 and 0.07 mm,respectively.However,Mean Curl,Kink Index and Kink Angle were not found any trend by age.In general,the correlations between same traits were different with different ages.The biggest negative correlations(-0.78)was found between Fiber Length and Fine Percentage at 4-year while the biggest positive correlations(0.98)was found between Kink Index and Kink Angle at 2-year and 4-year.

Regulation of Respiratory and Ligninolytic Enzyme Activity of Lentinula edodes by Selenium

The production of mushrooms enriched with essential elements, e.g. selenium, for human health is an interesting strategy to improve the functional foods supply. The selenium is an essential mineral and makes part of structure of enzymes involved in the oxidative metabolism. However, the selenium effect on the activity of respiratory and lignocellulolytic enzymes has not been considered. The understanding of this effect is important to determine the selenium concentration that increases the mushroom productivity and the degradation rate of the substrate. In this study, it was observed reduction of the respiratory activity of Lentinula edodes (Berk.) Pegler, the shiitake mushroom, in function of the increasing of the sodium selenite concentration in the substrate (p < 0.05). Selenium did not inhibit the activity of the hydrolytic enzymes (cellulase and xylanase), but it increased the activity of the oxidative enzyme (laccase). Respiratory activity of L. edodes has a negative correlation with sodium selenite concentration added in substrate. Thus is important to define the ideal dose of selenium to be added to the substrate for increasing lignocellulosic residues degradation and, consequently, guarantee a higher production of Se-enriched mushrooms.

Water yield and biomass production for on a eucalypt-dominated Mediterranean catchment under different climate scenarios

Worldwide,forests are vital in the regulation of the water cycle regulation and in water balance allocation.Knowledge of ecohydrological responses of production forests is essential to support management strategies,especially where water is already scarce.Shifting climatological patterns are expected to impact thermopluviometric regimes,water cycle components,hydrological responses,and plant physiology,evapotranspiration rates,crop productivity and land management operations.This work(1)assessed the impacts of different predicted climate conditions on water yield;(2)inferred the impacts of climate change on biomass production on eucalypt-to-eucalypt succes sion.To this end,the widely accepted Soil and Water Assessment Tool(SWAT)was run with the RCA,HIRHAM5 and RACMO climate models for two emission scenarios(RCP 4.5 and8.5).Three 12-year periods were considered to simulate tree growth under coppice regime.The results revealed an overall reduction in streamflow and water yield in the catchment in line with the projected reduction in total annual precipitation.Moreover,HIRHAM5 and RACMO models forecast a slight shift in seasonal streamflow of up to 2 months(for2024-2048)in line with the projected increase in precipitation from May to September.For biomass production,the extreme climate model(RCA)and severe emis sion scenario(RCP 8.5)predicted a decrease up to 46%.However,in the less extreme and more-correlated(with actual catchment climate conditions)climate models(RACMO and HIRHAM5)and in the less extreme emission scenario(RCP 4.5),biomass production increased(up to 20%),and the growth cycle was slightly reduced.SWAT was proven to be a valuable tool to assess climate change impacts on a eucalypt-dominated catchment and is a suitable decision-support tool for forest managers.

Axial variations in anatomical properties and basic density of Eucalypt urograndis hybrid(Eucalyptus grandis × E. urophylla)clones

We studied two clones of Eucalypt urograndis hybrid （Eucalyptus grandis × E. urophylla）, GR283 and GR330, grown in Tumkur district of Kamataka （India）, and felled 5-6 years old three trees of each clone. We recorded axial variations in heartwood content, bark properties, wood density and anatomical characteristics of wood in- cluding fibre length, fibre diameter, fibre wall thickness, lumen diameter, vessel frequency, vessel diameter and vessel element length. Clone GR283 had about 10 % heartwood, significantly lower than for clone GR330 （37 %）. Basic wood density along the tree height varied significantly within and between the clones. We observed significant variations in fibre length, fibre diameter and wall thickness within and between the two clones. Vessel frequency and vessel element length did not vary but vessel diameter differed significantly between the clones. With a greater proportion of sapwood, clone GR283 can be uti- lized for paper and pulp applications. Clone GR330 had a higher proportion of heartwood and lower wood density and, hence, is more suitable for light-weight material applications.

Some biological consequences of environmental change:A study using barnacles(Cirripedia:Balanomorpha)and gum trees(Angiospermae:Myrtaceae)

Uniformitarianism permits understanding of the past on the basis of the present,and modeling the future through consideration of the fossil record.The present paper addresses the impact environmental(climatic)change has had on acorn barnacles and eucalyptus trees.Acorn barnacles(Balanomorpha)are first recorded after the K/T massextinction event.In the Paleogene,rapid radiation resulted in their occupying most marine environments.That balanomorphs survived both the Paleocene–Eocene thermal maximum and the Pleistocene glaciation is testament to their ability to adapt to opportunities;they are known from the littoral(Chamaesipho)to depths of 3600 m(Tetrachaelasma)and within this from diverse substrates:rock,wood and miscellaneous flotsam,plus in symbiosis or commensalism with most larger marine organisms.Darwin’s(1854)view of the late Tertiary as the age of barnacles is reflected in their diversity,distribution and biomass.Barnacles are contrasted with the Australian Myrtaceae:plants ranging from woody shrubs to tall trees.The most significant is Eucalyptus sensu lato,which typifies Australia’s flora,and is characterized by aromatic leaves that produce eucalyptol.Eucalyptus has evolved strategies that result in its domination of Australian open woodlands:these include production of highly flammable eucalyptol oil(with a flashpoint of 49℃)and an unprecedented ability to regenerate following forest fires.Gum trees and barnacles first appear in the Paleogene,their earliest records are Australasian,and they both demonstrate extraordinary resilience when environmental conditions are optimal.

Structural development of vegetation on rehabilitated North Stradbroke Island:Above/belowground feedback may facilitate alternative ecological outcomes

Introduction:This study depicts broad-scale revegetation patterns following sand mining on North Stradbroke Island,south-eastern Queensland,Australia.Methods:Based on an ecological timeline spanning 4–20 years post-rehabilitation,the structure of these ecosystems(n=146)was assessed by distinguishing between periods of‘older’(pre-1995)and‘younger’(post-1995)rehabilitation practices.Results:The general rehabilitation outlook appeared promising,whereby an adequate forest composition and suitable levels of native biodiversity(consisting of mixed-eucalypt communities)were achieved across the majority of rehabilitated sites over a relatively short time.Still,older sites(n=36)appeared to deviate relative to natural analogues as indicated by their lack of under-storey heath and simplified canopy composition now characterised by mono-dominant black sheoak(Allocasuarina littoralis)reaching up to 60%of the total tree density.These changes coincided with lower soil fertility parameters(e.g.,total carbon,total nitrogen,and nutrient holding capacity)leading us to believe that altered growth conditions associated with the initial mining disturbance could have facilitated an opportunistic colonisation by this species.Once established,it is suspected that the black sheoak’s above/belowground ecological behaviour(i.e.,relating to its leaf-litter allelopathy and potential for soil-nitrogen fixation)further exacerbated its mono-dominant distribution by inhibiting the development of other native species.Conclusions:Although rehabilitation techniques on-site have undergone refinements to improve site management,our findings support that putative changes in edaphic conditions in combination with the competitive characteristics of some plant species can facilitate conditions leading to alternative ecological outcomes among rehabilitated ecosystems.Based on these outcomes,future studies would benefit from in depth spatio-temporal analyses to verify these mechanisms at finer investigative scales.

Advances in eucalypt research in China

Eucalypt plantations in China currently exceed4.5 Mhm^2, and this country has the third largest area of such plantations after India and Brazil. China's eucalypt industry now comprises a complex, multifaceted industry including seedling propagation, fertilizer production and supply, plantation silviculture, harvesting and transport,wood processing for products including lumber, pulp and paper, and wood-based panels, as well as bioenergy production and various forest byproducts and non-wood forest products. In 2015, the combined value of output of this whole industry was around 300 billion CNY. Chinese research and development(R&D) has been instrumental in supporting growth and development across the whole breadth of the country's eucalypt industry. In this report,recent advances in this R&D are reviewed under six key topics:(1) advanced propagation technology;(2) genetic resources and breeding;(3) targeted silviculture;(4) eucalypt disease and pest management;(5) enhancing plantation ecology and sustainability; and(6) wood processing and byproduct technology. R&D has greatly facilitated expansion and proliferation of all parts of China's eucalypt industry. This industry is now of major importance to China's economy; it involves tens of thousands of growers and companies that provide livelihoods for hundreds of thousands of people.

Bacterial Wilt and Boron Deficiency Stress:A New Disorder in Eucalypt Plantations in South China

This paper reports on a new disorder that first appeared in eucalypt plantations in south China in2003. The plantations were destructively sampled near Leizhou, Yanxi, Kaiping and Gaoyao in September toDecember 2003. Whilst some 5% of 0.5 to 1.5 year-old Eucalyptus urophylla trees declined rapidly andexhibited symptoms of wilting, the majority of the affected trees declined slowly and exhibited two foliarsymptoms. Young leaves initially developed an interveinal chlorosis extending from the leaf margin inwardsto the midrib. Most leaves then developed pockets of necrotic tissue that became bleached but typically hadbrown margins. The former symptoms have been recognised as being caused by limited boron supply in soil,but the latter symptoms have not been previously observed in eucalypts in China. Inorganic analysisshowed that the leaves with the latter symptoms had deficient B concentrations whereas the leaves fromhealthy trees had adequate B concentrations. Bacterial wilt, Ralstonia solanacearum, was present at all siteswhere foliar symptoms and tree death were present. The root system of all trees with foliar chlorosis andnecrosis had signs of infection in some roots and attrition of lateral roots. The trunk and branches of therecently died trees and the trees with advanced leaf drop had discoloured xylem, which on cutting, oozedbacterial slime. Possible relationships between root damage caused by abiotic (e.g. typhoons, root damagefrom hand weeding) and biotic factors and reduced B uptake are discussed. Recommendations are made forreducing bacterial wilt disease and improving B management in fast-growing short-rotation eucalypt plantations.

Plant growth in a fragmented forest is a consequence of top-down and bottom-up processes, but not their interaction

Aims Habitat loss and fragmentation are the leading causes of global biodiversity decline.How fragmentation(leading to edge effects,increased isolation and declining habitat size)interacts with top-down processes like vertebrate herbivory,an important driver of vegetation structure and composition in many ecosystems,is poorly quantified.Interactions between fragmentation and changes in her-bivory may exacerbate their individual influences on plant growth,with implications for management of native plant communities within fragmented landscapes.We examined the effects of habitat fragmentation on herbivore activity,and also how both fragmen-tation and mammalian herbivory influence growth of understorey plant species.Methods This study was conducted at the Wog Wog habitat fragmentation experiment,located in south-eastern New South Wales,Australia.We use herbivore exclusion plots across an experimentally frag-mented landscape to assess the interactive effects of fragmenta-tion and herbivory on the growth of four plant species that vary in growth form and rarity in the landscape.Important Findings We observed species-specific responses to both herbivory and fragmentation,but no additive or interactive effects between these drivers.We show that a reduction in herbivore activity within frag-ments does not correspond with an increase in plant growth,even for the most palatable species.Rather,top-down processes continue to operate across the fragmented landscape.Although changes in habitat conditions within fragments appear to negatively influence both plant growth and mammalian herbivore activity,it is likely that alterations to bottom-up effects(i.e.fragmentation)may be more important than top-down effects(i.e.herbivores)for the spe-cies under investigation.The species-specific response of plants to herbivory or fragmentation may have implications for temporal and spatial population persistence in fragmented landscapes and ulti-mately fragment vegetation structure.

State of Further Processing of Tropical Timber in China

This paper, from the development of Chinese economy and forest resources as well as the fast-growing and high-yield timber plantation development program and harvesting policies of plantation, analyses the Eucalypt planting, processing, utilization and developing prospect in tropical area.

Effects of Applying New-style Growth Hormone on Eucalypt Cuttage

Diethyl aminoethyl hexanoate AC is a new-style growth hormone that induces cuttings to root by molecule signal. With Eucalptus urophylla and E. urophyllaxE, grandis as testing varieties, effects of applying different growth hormones on eucalypt cuttage were compared through experiments, and the result showed that diethyl aminoethyl hexanoate AC made cuttings root 4 days earlier than other common growth hormones did. The average rooting rate and the mean root quantity of diethyl aminoethyl hexanoate AC treated cuttings were 11%-26.5% higher than and 1.8-8.5 pieces per cutting more than those in other treatments. Besides, the seedlings were excellent. The new-style growth hormone improves cuttage of eucalypt to a higher level.