Eucalyptus Microcarpa Research Articles

Tree failure - A natural phenomenon with forensic implications.

Tree failure, or summer branch drop, refers to situations where large branches or whole trees may unexpectedly drop on unsuspecting victims. On occasion, this involves vehicles impacted by falling overhanging trees or branches. To study this phenomenon further review of the Forensic Science SA, Adelaide, Australia, database and an internet news search were undertaken over a 20 year period from March 2004 to February 2024 for all cases where unexpected accidental deaths in South Australia had been caused by falling branches or trees. There were six cases (age range 12-63 years; average 39 years; M:F 1:2). Three deaths occurred when branches dropped onto vehicles being driven along roads, 2 occurred when entire trees dropped onto the victims (one in windy weather) and 1 was due to a branch drop. Three tree species were identified as a grey box gum tree (Eucalyptus microcarpa), a lemon-scented gum tree (Corymbia citriodora) and a Cottonwood tree (Populus deltoides). The remainder were variants of eucalyptus (gum) trees. Deaths due to tree failures are uncommon and may involve a variety of different tree species with these events not necessarily occurring during high winds or storms. The major findings at autopsy are blunt force injuries.

Estimates of heterozygosity from single nucleotide polymorphism markers are context-dependent and oftenwrong.

Genetic diversity is frequently described using heterozygosity, particularly in a conservation context. Often, it is estimated using single nucleotide polymorphisms (SNPs); however, it has been shown that heterozygosity values calculated from SNPs can be biased by both study design and filtering parameters. Though solutions have been proposed to address these issues, our own work has found them to be inadequate in some circumstances. Here, we aimed to improve the reliability and comparability of heterozygosity estimates, specifically by investigating how sample size and missing data thresholds influenced the calculation of autosomal heterozygosity (heterozygosity calculated from across the genome, i.e. fixed and variable sites). We also explored how the standard practice of tri- and tetra-allelic site exclusion could bias heterozygosity estimates and influence eventual conclusions relating to genetic diversity. Across three distinct taxa (a frog, Litoria rubella; a tree, Eucalyptus microcarpa; and a grasshopper, Keyacris scurra), we found heterozygosity estimates to be meaningfully affected by sample size and missing data thresholds, partly due to the exclusion of tri- and tetra-allelic sites. These biases were inconsistent both between species and populations, with more diverse populations tending to have their estimates more severely affected, thus having potential to dramatically alter interpretations of genetic diversity. We propose a modified framework for calculating heterozygosity that reduces bias and improves the utility of heterozygosity as a measure of genetic diversity, whilst also highlighting the need for existing population genetic pipelines to be adjusted such that tri- and tetra-allelic sites be included in calculations.

Establishing a climate‐ready revegetation trial in central Victoria – A case study

SummaryA promising approach in dealing with the detrimental effects of climate change on vegetation is to introduce pre‐adapted genotypes into restoration programmes. Bush Heritage’s Victorian reserves have experienced eucalypt dieback probably due to intense drought and heat shock linked to climate change. Planned revegetation on the Nardoo Hills reserve provided an opportunity to establish and test the potential for new climate‐matched genotypes to expand the adaptive capacity of the plantings. As NRM practitioners, here we document our experiences in implementing this approach. Using the Climate Analogues tool and the Australasian Virtual Herbarium, we selected provenances from four climate analogue regions where remnants of our focal species, Grey Box (Eucalyptus microcarpa) and Yellow Box (E. melliodora), were located. Replicated plots were established covering five provenances for Grey Box and 5 provenances for Yellow Box with up to 10 ‘families’ (mother trees) per provenance. Numerous challenges were encountered including locating suitable provenances, the design and scientific compromises associated with the experimental layout, sourcing of adequate seed from remote regions (especially drought affected) and high mortality during seedling establishment. Monitoring nine months after planting revealed not only high overall mortality (around 70%, probably due to drought conditions during establishment) but also significant differences in height between provenances and in mortality and height among families in both species. Despite the initial mortality, the nested design and level of replication applied in these plots appear adequate to test hypotheses about the value of climate matching and will continue to be monitored in the future.

Opportunities and challenges in assessing climate change vulnerability through genomics

By investigating how past selection has affected allele frequencies across space, genomic tools are providing new insights into adaptive evolutionary processes. Now researchers are considering how this genomic information can be used to predict the future vulnerability of species under climate change. Genomic vulnerability assessments show promise, but challenges remain.

Combined Analyses of Phenotype, Genotype and Climate Implicate Local Adaptation as a Driver of Diversity in Eucalyptus microcarpa (Grey Box)

Trees are a keystone species in many ecosystems and a critical component of ecological restoration. Understanding their capacity to respond to climate change is essential for conserving biodiversity and determining appropriate restoration seed sources. Patterns of local adaptation to climate between populations within a species can inform such conservation decisions and are often investigated from either a quantitative trait or molecular genetic basis. Here, we present findings from a combined analysis of phenotype (quantitative genetic analysis), genotype (single nucleotide polymorphism (SNP) trait associations), and climate associations. We draw on the strength of this combined approach to investigate pre-existing climate adaptation and its genetic basis in Eucalyptus microcarpa (Grey box), an important tree for ecological restoration in south-eastern Australia. Phenotypic data from a 26-year-old provenance trial demonstrated significant genetic variation in growth and leaf traits at both the family and provenance levels. Growth traits were only associated with temperature, whilst leaf traits were associated with temperature, precipitation and aridity. Genotyping of 40 putatively adaptive SNPs from previous genome-wide analyses identified 9 SNPs associated with these traits. Drawing on previous SNP–climate association results, several associations were identified between all three comparisons of phenotype, genotype and climate. By combining phenotypic with genomic analyses, these results corroborate genomic findings and enhance understanding of climate adaptation in E. microcarpa. We discuss the implication of these results for conservation management and restoration under climate change.

Evidence of genomic adaptation to climate in Eucalyptus microcarpa: Implications for adaptive potential to projected climate change.

Understanding whether populations can adapt insitu or whether interventions are required is of key importance for biodiversity management under climate change. Landscape genomics is becoming an increasingly important and powerful tool for rapid assessments of climate adaptation, especially in long-lived species such as trees. We investigated climate adaptation in Eucalyptus microcarpa using the DArTseq genomic approach. A combination of FST outlier and environmental association analyses were performed using >4200 genomewide single nucleotide polymorphisms (SNPs) from 26 populations spanning climate gradients in southeastern Australia. Eighty-one SNPs were identified as putatively adaptive, based on significance in FST outlier tests and significant associations with one or more climate variables related to temperature (70/81), aridity (37/81) or precipitation (35/81). Adaptive SNPs were located on all 11 chromosomes, with no particular region associated with individual climate variables. Climate adaptation appeared to be characterized by subtle shifts in allele frequencies, with no consistent fixed differences identified. Based on these associations, we predict adaptation under projected changes in climate will include a suite of shifts in allele frequencies. Whether this can occur sufficiently rapidly through natural selection within populations, or would benefit from assisted gene migration, requires further evaluation. In some populations, the absence or predicted increases to near fixation of particular adaptive alleles hint at potential limits to adaptive capacity. Together, these results reinforce the importance of standing genetic variation at the geographic level for maintaining species' evolutionary potential.

Landscape genomics reveals altered genome wide diversity within revegetated stands of Eucalyptus microcarpa (Grey Box).

In order to contribute to evolutionary resilience and adaptive potential in highly modified landscapes, revegetated areas should ideally reflect levels of genetic diversity within and across natural stands. Landscape genomic analyses enable such diversity patterns to be characterized at genome and chromosomal levels. Landscape-wide patterns of genomic diversity were assessed in Eucalyptus microcarpa, a dominant tree species widely used in revegetation in Southeastern Australia. Trees from small and large patches within large remnants, small isolated remnants and revegetation sites were assessed across the now highly fragmented distribution of this species using the DArTseq genomic approach. Genomic diversity was similar within all three types of remnant patches analysed, although often significantly but only slightly lower in revegetation sites compared with natural remnants. Differences in diversity between stand types varied across chromosomes. Genomic differentiation was higher between small, isolated remnants, and among revegetated sites compared with natural stands. We conclude that small remnants and revegetated sites of our E.microcarpa samples largely but not completely capture patterns in genomic diversity across the landscape. Genomic approaches provide a powerful tool for assessing restoration efforts across the landscape.

Comparing the impacts of different types of recreational trails on grey box grassy-woodland vegetation: lessons for conservation and management

Tourism and recreation are popular in natural areas but can damage plant communities, including those of high conservation value in protected areas. This includes impacts from recreational trails, but what type of trail has the most impact and why? We compared the impacts of five different trails (narrow, intermediate and wide bare earth trails, intermediate gravel trails and wide tarmac trails) on the endangered grey box grassy-woodland (Eucalyptus microcarpa (Maiden) Maiden) in Belair National Park near Adelaide in South Australia. First, the extent, width and area of recreational trails in the remnant woodland were mapped. Then, vegetation parameters were recorded in quadrats at three distances from the edge of trails in the woodland, with 10 replicate sites per trail type and single quadrats at 10 control sites (i.e. total 60 sites, 160 quadrats). All trails resulted in vegetation loss on the trail surface and along the edges of the trails, as well as changes in vegetation composition, including reductions in shrubs and bulbs close to the trail. The most common types of trail were bare earth trails with an average width of 2.5 m (50% of trails) which resulted in the greatest soil loss (>88 000 m3) and vegetation loss (33 899 m2 or 3.4 ha) in the 167 ha woodland remnant overall. Wider (5.4 m) hardened tarmac trails, however, were associated with low species richness, high cover of exotic grasses and few herbs, shrubs and bulbs compared with vegetation away from trails and closer to other trails. Therefore a mixed approach to the provision of trails may be most appropriate, with hardened trails used in areas of highest use, but in some circumstances leaving trails unhardened may be more appropriate where they are likely to remain narrow and where there is less likely to be erosion and/or safety issues.

Climatic and photoperiodic effects on flowering phenology of select eucalypts from south-eastern Australia

Flowering phenology plays an important role in the plant life cycle as it is sensitive to climate. The timing and intensity of flowering is important for the reproductive success, fitness, survival and diversity of plants. Its study in relation to the environment can therefore aid in understanding the response of species to climate change. Long-term studies examining the relationship between flowering phenology and climate are limited in Australia. This study explores the effect of photoperiod length, temperature and rainfall on flowering duration and intensity of Eucalyptus tricarpa, Eucalyptus microcarpa and Eucalyptus polyanthemos using long term data sets from two locations and the statistical model: generalised additive model for location, scale and shape (GAMLSS). The study further incorporates the phenological response to calibrate the flowering sub-module of the mechanistic model TACA-GEM to investigate the effect of predicted climate change on flowering phenology. Flowering intensity of E. microcarpa increased as temperatures warmed in the months prior to flowering but declined when warmer temperatures occurred in the early stages of bud development. For E. polyanthemos flowering decreased with increases in temperature combined with decreased rainfall and shorter days. Increased rainfall, cooler temperatures and shorter days increased flowering in E. tricarpa. Modelling of species response to climate change showed that decreases in flowering intensity and duration for all three species are likely. The temperature thresholds required for flowering of E. polyanthemos were exceeded under climate change while the requirement for longer days prevented flowering phenology shifting to cooler months. E. tricarpa exhibited a decline in flowering intensity and duration under climate change; however, its requirements for shorter days allowed the species to continue to flower during winter. E. microcarpa displayed no consistent relationship to photoperiod and a decline in flowering intensity and duration under climate change was modelled. The species’ specific responses to photoperiod suggests that flowering asynchrony between the coexisting species may be linked to day length and that the asynchrony will be strengthened under climate change as flowering duration and intensity contract under a warmer and drier climate.

Environmental effects on germination phenology of co-occurring eucalypts: implications for regeneration under climate change.

Germination is considered one of the important phenological stages that are influenced by environmental factors, with timing and abundance determining plant establishment and recruitment. This study investigates the influence of temperature, soil moisture and light on the germination phenology of six Eucalyptus species from two co-occurring groups of three species representing warm-dry and cool-moist sclerophyll forests. Data from germination experiments were used to calibrate the germination module of the mechanistic model TACA-GEM, to evaluate germination phenology under a range of climate change scenarios. With the exception of E. polyanthemos, the optimal niche for all species was characterised by cool-moist stratification, low light, cool temperatures and high soil moisture. Model results indicated that of the warm-dry species, Eucalyptus microcarpa exhibited greater germination and establishment under projected changes of warmer drier conditions than its co-occurring species Eucalyptus polyanthemos and Eucalyptus tricarpa which suggests that E. microcarpa could maintain its current distribution under a warmer and drier climate in southeastern Australia. Among the cool-moist species, Eucalyptus radiata was the only species that established under projected climate change of the 2080s but at such a low probability that its persistence compared to Eucalyptus obliqua and Eucalyptus sieberi cannot be posited. For all cool-moist species, germination did not benefit from the phenological shifts they displayed. This study successfully demonstrated environmental effects on germination phenology and how a shift in climate can influence the timing and success of recruitment.

Nematodes from galls on Myrtaceae. IV. Fergusobia from flat leaf galls onEucalyptus and Corymbia, with descriptions of two new species.

Two new species of Fergusobia are described. Both were collected from flat leaf galls from South Australia, one on Eucalyptus microcarpa and the other on E. porosa. Fergusobia microcarpae n. sp. Davies is characterised by the combination of a C-shaped parthenogenetic female with a short, broadly rounded conoid tail, an arcuate to open C-shaped infective female with an hemispherical tail tip, and arcuate to J-shaped males with angular spicules and short peloderan bursa. Fergusobia porosae n. sp. Davies is similar in having an arcuate to C-shaped parthenogenetic female with a small conoid tail, an almost straight to arcuate infective female with an hemispherical tail tip, and males that are almost straight to barely J-shaped with angular spicules and short peloderan bursa. They differ in that the bodies of parthenogenetic and infective females of F. microcarpae n. sp. are more curved than in F. porosae n. sp. Other known similar forms of Fergusobia/Fergusonina galls are outlined and the larval shield morphologies of their associated mutualistic Fergusonina fly species are discussed where known. An inventory of all known Fergusobia/Fergusonina associations from flat leaf galls from Corymbia spp. and Eucalyptus spp. is presented. Relationships of Fergusobia nematodes were inferred from analysis of sequences of 28S rDNA D2/D3 domains and a portion of mitochondrial DNA cytochrome oxidase subunit I (mtCOI). Nematodes from flat leaf galls appeared in two clades.

Environmental effects on growth phenology of co-occurring Eucalyptus species

Growth is one of the most important phenological cycles in a plant's life. Higher growth rates increase the competitive ability, survival and recruitment and can provide a measure of a plant's adaptive capacity to climate variability and change. This study identified the growth relationship of six Eucalyptus species to variations in temperature, soil moisture availability, photoperiod length and air humidity over 12months. The six species represent two naturally co-occurring groups of three species each representing warm-dry and the cool-moist sclerophyll forests, respectively. Warm-dry eucalypts were found to be more tolerant of higher temperatures and lower air humidity than the cool-moist eucalypts. Within groups, species-specific responses were detected with Eucalyptus microcarpa having the widest phenological niche of the warm-dry species, exhibiting greater resistance to high temperature and lower air humidity. Temperature dependent photoperiodic responses were exhibited by all the species except Eucalyptus tricarpa and Eucalyptus sieberi, which were able to maintain growth as photoperiod shortened but temperature requirements were fulfilled. Eucalyptus obliqua exhibited a flexible growth rate and tolerance to moisture limitation which enables it to maintain its growth rate as water availability changes. The wider temperature niche exhibited by E. sieberi compared with E. obliqua and Eucalyptus radiata may improve its competitive ability over these species where winters are warm and moisture does not limit growth. With climate change expected to result in warmer and drier conditions in south-east Australia, the findings of this study suggest all cool-moist species will likely suffer negative effects on growth while the warm-dry species may still maintain current growth rates. Our findings highlight that climate driven shifts in growth phenology will likely occur as climate changes and this may facilitate changes in tree communities by altering inter-specific competition.

Arthropod assemblages in a focal tree species (Eucalyptus microcarpa) depends on the species mix in restoration plantings

The composition of arthropods in trees has long been a topic of interest, with many studies exploring ways in which arthropod communities differ among tree species or entire forests. Few studies, however, have examined arthropods from trees in restoration plantings, and little is known about how different tree plantings might lead to different biodiversity outcomes. The aim of our study was to determine if a focal tree species hosted a different arthropod fauna depending on its context. We examined arthropod assemblages from the foliage of Eucalyptus microcarpa (Grey Box) trees present in two kinds of plantings: (i) simple plantings with only Eucalyptus trees, and (ii) mixed plantings with both Eucalyptus and Acacia trees. We examined the composition of the assemblages, and looked for associations between ant and psyllid (Hemiptera) diversity across each kind of planting. We found more species of psyllids, beetles and ants in E. microcarpa trees when they were grown in simple plantings compared with the mixed species plantings. We also found that psyllid richness and abundance was positively correlated with ant richness and abundance across all plantings. Our study shows that a more diverse context (i.e. a mixed planting) is not necessarily associated with a more diverse fauna within a focal tree species, and that simple Eucalyptus-only plantings may encourage higher numbers of insect herbivores. The apparent association between psyllids and ants suggests a complex interaction that may drive patterns in tree arthropod assemblages.

Hollow occurrence and abundance varies with tree characteristics and among species in temperate woodlandEucalyptus

Tree hollows are a critical but diminishing resource for a wide range of fauna around the world. Conservation of these fauna depends on sustainable management of tree species that produce the hollows on which they depend. This study addressed the need for empirical data about intraspecific and interspecific variation in hollow occurrence and abundance in woodland trees in Australia. We measured and performed hollow surveys on 1817 trees of seven species of woodland Eucalyptus in central-western New South Wales, Australia. Trees were surveyed at 51 one-hectare sites and about 30% of trees surveyed had multiple stems. Generalized linear mixed models that accounted for nestedness of stems within trees and trees within sites detected a significant amount of variation in hollow occurrence and abundance. Models for individual tree stems of live trees showed hollow probability and abundance increased with diameter at breast height (DBH) and with increasing senescence (form). Stems of Eucalyptus microcarpa Maiden had a higher probability of having hollows than similar DBH stems of Eucalyptus camaldulensis Dehnh., Eucalyptus melliodora A.Cunn. ex Schauer or Eucalyptus populnea ssp. bimbil L.A.S.Johnson & K.D.Hill. Dead stems in live trees were more likely to have hollows than live stems of similar DBH. Each stem in a multi-stemmed tree had a lower probability of hollow occurrence and lower abundance of hollows than single-stemmed trees of similar DBH. For stems of dead trees, hollow occurrence and abundance increased with DBH and differed depending on stage of senescence. A comparison of our data with other studies indicates regional variation of hollow abundances within tree species.

Promicromonospora endophytica sp. nov., an endophytic actinobacterium isolated from the root of an Australian native Grey Box tree

A novel aerobic actinobacterium, strain EUM 273(T), was isolated from the root of a Grey Box tree (Eucalyptus microcarpa Maiden). Cells were Gram-staining-positive with well-developed substrate mycelia which were non-motile and rod-like, with coccoid elements. Phylogenetic evaluation based on 16S rRNA gene sequence analysis placed the isolate as a member of the family Promicromonosporaceae that was most closely related to Promicromonospora xylanilytica YIM 61515(T) (98.2%) and Promicromonospora vindobonensis V45(T) (98%). Chemotaxonomic data including cell wall components, major menaquinone and major fatty acids confirmed the affiliation of strain EUM 273(T) to the genus Promicromonospora. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain EUM 273(T) from the closest related species with validly published names. The name proposed for the novel species is Promicromonospora endophytica sp. nov. The type strain is EUM 273(T) (=DSM 23716(T)=NRRL B-24816(T)).

Pseudonocardia eucalypti sp. nov., an endophytic actinobacterium with a unique knobby spore surface, isolated from roots of a native Australian eucalyptus tree

A novel strain, designated EUM 374(T), was isolated from the root of a native Australian eucalyptus tree, Eucalyptus microcarpa, and subjected to a range of morphological, phylogenetic and chemotaxonomic analyses. The strain was Gram-reaction-positive with well-developed aerial mycelia, which fragmented into rod-shaped spores that had unique knobby protrusions on the spore surface. Substrate mycelia were not present in the media used. Strain EUM 374(T) grew as a film on the surface of static liquid culture medium but did not grow under shaking conditions. Phylogenetic evaluation based on 16S rRNA gene sequences identified the new isolate as belonging to the family Pseudonocardiaceae with sequence similarities of 96.1 and 96.3 % to Pseudonocardia acaciae GMKU095(T) and Pseudonocardia spinosispora LM 141(T), respectively, and 93-96 % sequence similarity to other members of the genus Pseudonocardia. The results of comprehensive phylogenetic analyses, including physiological and biochemical tests, differentiated strain EUM 374(T) from related members of the genus Pseudonocardia. Based on the phenotypic, phylogenetic and chemotaxonomic evidence, strain EUM 374(T) represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia eucalypti sp. nov. is proposed. The type strain is EUM 374(T) ( = DSM 45351(T) = ACM 5285(T)).

Pseudonocardia adelaidensis sp. nov., an endophytic actinobacterium isolated from the surface-sterilized stem of a grey box tree (Eucalyptus microcarpa)

An aerobic, actinobacterial strain with rod-shaped spores, EUM 221(T) [corrected], which was isolated from the surface-sterilized stem of a grey box tree (Eucalyptus microcarpa), is described. Phylogenetic evaluation based on 16S rRNA gene sequence similarity showed that this isolate belongs to the family Pseudonocardiaceae, with the closest neighbour being Pseudonocardia zijingensis 6330(T) (98.7 %). The level of 16S rRNA gene sequence similarity between the isolate and species of the genus Pseudonocardia with validly published names ranged from 95 to 98 %. Chemotaxonomic data (meso-diaminopimelic acid; major menaquinone MK-8(H(4)); major fatty acid iso-C(16 : 0)) confirmed the affiliation of strain EUM 221(T) [corrected] to the genus Pseudonocardia. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain EUM 221(T) [corrected] from the closest described species. Therefore, this strain represented a novel species and the name proposed is Pseudonocardia adelaidensis sp. nov. The type strain is EUM 221(T) [corrected] (=DSM 45352(T) =ACM 5286(T)).

Can climate at the seed-source predict the success of eucalypts planted on sites that have been grazed for over 100 years?

Abstract Many regions of southern Australia exposed to broad-acre grazing are denuded of trees. Re-establishing trees in these landscapes is important for both environmental and economic reasons. We investigated whether climate at the site of origin of the seed can inform species selection for tree establishment on ex-pasture sites within agricultural landscapes. We established trials at four sites in the sheep and cattle grazing region of the Midlands of Tasmania at: ‘Woodland Park’; ‘Sorrel Springs’; ‘Inverel’ and ‘Glen Morey’ farms (long-term average rainfalls of 584, 520, 520, and 479 mm, respectively). Eucalypt species were selected, based on high tolerance to frost and drought inferred from climate at the sites of origin and based on the limited scientific literature available, from across Tasmania and mainland Australia. We investigated the mortality, health and height growth of 18 eucalypt species three months, one and six years after planting. Climatic data from the site of origin of the seed of these species was used to group species into categories of mean annual temperature and mean annual rainfall at seed-source. Sensitivity of species to environment was investigated and compared using modified joint regression. At three planting sites, Woodland Park, Sorrel Springs (except health of the temperature category comparison at six years) and Inverel, we found significantly greater height and health one and six years after planting for local (Tasmanian) compared to non-local (Australian mainland) species, and for species where the site of origin of seed was categorised as low or medium mean annual temperature compared with those categorised as high mean annual temperature. There were no significant differences in mortality for these comparisons. At Glen Morey, height was significantly greater at six years after planting of local compared to non-local species and of species from low and medium mean annual temperature categories compared with the high mean annual temperature category. Mortality was significantly greater in local than non-local species six years after planting. Health was not significantly different for these comparisons. Differences in height, health or mortality of species categorised into mean annual rainfall at seed-source were largely non-significant at all sites one and six years after planting. A study of the sensitivity of species to environment of planting indicated that Tasmanian species were less sensitive than mainland species when height data was compared. When health data was compared, species with a site of origin of seed categorised as low rainfall were less sensitive to environment than species categorised as medium and high-mean rainfall. When mortality data was used significant differences were identified in the sensitivity of species to planting environment but this was not related to locality, mean annual temperature or rainfall at seed-source. Species that attained above average height and low mortality across three or more sites included Eucalyptus pulchella, Eucalyptus perineana (Tasmanian species), and Eucalyptus microcarpa, Eucalyptus benthamii and Eucalyptus melliodora (mainland species). Whilst temperature (and to a lesser extent rainfall) at seed-source is a good indicator of the success of tree establishment, high variability between sites points to the need to consider climate, browsing pressure and farm management at the paddock-scale when planning revegetation plantings. This has important implications for carbon sequestration plantings.

Eucalyptus recruitment in degraded woodlands: no benefit from elevated soil fertility

Grasses and forbs compete heavily with young tree seedlings for available resources, greatly reducing tree seedling establishment success. Soil nutrient enrichment associated with agricultural intensification can increase the growth of both herbaceous and woody lifeforms growing in isolation, but may change the balance of competitive advantage when growing together. The effects of nitrogen and phosphorus enrichment on pasture biomass and competition with two Australian grassy woodland trees (Eucalyptus albens and Eucalyptus microcarpa) was investigated in a field plot trial. Soil nutrients increased pasture biomass, but had no measurable effect on tree growth in our experiment. Competition from pasture species, even at low levels, led to high tree seedling mortality and greatly reduced tree seedling growth compared with pasture-free plots. However, when pasture-free plots were excluded from the analysis, tree seedling leaf area was not strongly correlated with herbaceous biomass. Tree seedling establishment was severely restricted even at the lowest levels of pasture biomass. We conclude that increased soil fertility resulted in a competitive advantage to the pasture, and does not improve tree seedling establishment when grown either with or without exotic herbaceous pasture (grassy understorey) species.

Box Mistletoe (Amyema miquelii) parasitism is not detrimental to the health of Grey Box (Eucalyptus microcarpa) trees at a regional scale

Ecological Management & RestorationVolume 10, Issue 2 p. 148-150 Box Mistletoe (Amyema miquelii) parasitism is not detrimental to the health of Grey Box (Eucalyptus microcarpa) trees at a regional scale Lindy M. MacRaild, Lindy M. MacRaildSearch for more papers by this authorJames Q. Radford, James Q. RadfordSearch for more papers by this authorAndrew F. Bennett, Andrew F. BennettSearch for more papers by this author Lindy M. MacRaild, Lindy M. MacRaildSearch for more papers by this authorJames Q. Radford, James Q. RadfordSearch for more papers by this authorAndrew F. Bennett, Andrew F. BennettSearch for more papers by this author First published: 31 July 2009 https://doi.org/10.1111/j.1442-8903.2009.00476.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume10, Issue2August 2009Pages 148-150 RelatedInformation