Forestry Tree Research Articles

The effect of conditioning Acacia mearnsii De Wild. hedge-plants under shadenetting on rooting, elemental uptake and productivity of cuttings

Acacia mearnsii is a commercial forestry tree in South Africa, largely grown from open-pollinated seeds. Clonal deployment of superior selections of the species is restricted due to its poor rooting ability. The effects of conditioning parent hedge-plants under three levels of reduced light (80% black; 60% red and 40% black/ white shadenet) were investigated. Hedge-plant nutrition, carbohydrate content, productivity and rooting of cuttings were measured. Conditioning hedge-plants under 80% black shadenet for five weeks gave the highest rooting percentages in both seasons (39.3% and 22.1%) (p < 0.05), despite having a lower productivity of 42.5 cuttings per hedge-plant (p > 0.05). As the shading increased to 80% black, so the rooting increased, and stem/leaf total non-structural carbohydrate levels decreased (r = −0.61 to −0.97). Conditioning under shadenet reduced leaf and increased stem total macronutrient percentages but increased both leaf and stem total micronutrient concentrations. Total macro- and micronutrient levels were greatest after conditioning under 80% black shadenet, except for stem-nitrogen, stem-carbon and leaf-manganese, which had the lowest values (p > 0.05). In conclusion, hedge-plant conditioning under 80% black shadenet can significantly improve rooting of A. mearnsii cuttings, which could facilitate the commercial clonal propagation of the species.

Scanning RNA-Seq and RAD-Seq approach to develop SNP markers closely linked to MALE STERILITY 1 (MS1) in Cryptomeria japonica D. Don.

Cryptomeria japonica is a major forestry tree species in Japan. Male sterility of the species is caused by a recessive gene, which shows dysfunction of pollen development and results in no dispersed pollen. Because the pollen of C. japonica induces pollinosis, breeding of pollen-free C. japonica is desired. In this study, single nucleotide polymorphism (SNP) markers located at 1.78 and 0.58 cM to a male sterility locus (MS1) were identified from an analysis of RNA-Seq and RAD-Seq, respectively. SNPs closely linked to MS1 were first scanned by a method similar to MutMap, where a type of index was calculated to measure the strength of the linkage between a marker sequence and MS1. Linkage analysis of selected SNP markers confirmed a higher efficiency of the current method to construct a partial map around MS1. Allele-specific PCR primer pair for the most closely linked SNP with MS1 was developed as a codominant marker, and visualization of the PCR products on an agarose gel enabled rapid screening of male sterile C. japonica. The allele-specific primers developed in this study would be useful for establishing the selection of male sterile C. japonica.

Effect of age and spacing on biomass production in forest plantations

ABSTRACT The aim of this study was to determine the effect of age and plant spacing on biomass production of four forestry tree species: Acacia mearnsii De Wild, Eucalyptus grandis W. Hill ex Maiden, Mimosa scabrella Benth, and Ateleia glazioviana Baill. The following spacings of plants at the ages of 1, 3, and 5 years after planting were considered: 2.0 × 1.0 m, 2.0 × 1.5 m, 3.0 × 1.0 m, and 3.0 × 1.5 m. The study was installed in randomized complete block design. Biomass was determined by weighing different components of the trees after harvesting. Plant spacing affected biomass production of forestry trees at different ages after planting. Dense spacings produced larger quantities of biomass than less dense spacing. The tree species differed in biomass production: Eucalyptus grandis produced the largest quantity (325.1 t ha-1), followed by Acacia mearnsii (239.3 t ha-1), Mimosa scabrella (53.4 t ha-1), and Ateleia glazioviana (32.1 t ha-1). Wood biomass represented the biomass component with the largest production over time, which showed an increasing proportion throughout the age groups, followed branch, leaf, and bark biomass.

Development and evaluation of novel salt-tolerant Eucalyptus trees by molecular breeding using an RNA-Binding-Protein gene derived from common ice plant (Mesembryanthemum crystallinum L.).

SummaryThe breeding of plantation forestry trees for the possible afforestation of marginal land would be one approach to addressing global warming issues. Here, we developed novel transgenic Eucalyptus trees (Eucalyptus camaldulensis Dehnh.) harbouring an RNA‐Binding‐Protein (McRBP) gene derived from a halophyte plant, common ice plant (Mesembryanthemum crystallinum L.). We conducted screened‐house trials of the transgenic Eucalyptus using two different stringency salinity stress conditions to evaluate the plants’ acute and chronic salt stress tolerances. Treatment with 400 mM NaCl, as the high‐stringency salinity stress, resulted in soil electrical conductivity (EC) levels >20 mS/cm within 4 weeks. With the 400 mM NaCl treatment, >70% of the transgenic plants were intact, whereas >40% of the non‐transgenic plants were withered. Treatment with 70 mM NaCl, as the moderate‐stringency salinity stress, resulted in soil EC levels of approx. 9 mS/cm after 2 months, and these salinity levels were maintained for the next 4 months. All plants regardless of transgenic or non‐transgenic status survived the 70 mM NaCl treatment, but after 6‐month treatment the transgenic plants showed significantly higher growth and quantum yield of photosynthesis levels compared to the non‐transgenic plants. In addition, the salt accumulation in the leaves of the transgenic plants was 30% lower than that of non‐transgenic plants after 15‐week moderate salt stress treatment. There results suggest that McRBP expression in the transgenic Eucalyptus enhances their salt tolerance both acutely and chronically.

Uses and ecosystem services of trees outside forest (TOF)-A case study from Uttar Banga Krishi Viswavidyalaya, West Bengal, India

Trees outside Forest (TOF) play a critical role in conservation of floristic diversity apart from being reservoirs of other ecosystem services. TOF includes all the trees, attained 10 cm or more diameters at breast height, available on lands, which is not notified as forests. The present study was conducted in the Pundibari campus of Uttar Banga Krishi Viswavidyalaya to document the available tree diversity and their potential uses and ecosystem services. A total of 1816 numbers of individuals with dbh ≥ 10 cm of 95 woody perennials species were inventoried belonging to 79 genera and 38 families. The contribution among number of individuals was dominated by Mangifera indica with (9.19%). The overall dominant family was Fabaceae represented by 11 species followed by Arecaceae and Meliaceae. The contribution of inventoried 95 species was dominated by forestry tree species followed by road isde plantation, fruit crops and plantation crops respectively. The highest number of individuals among forestry plantation was for Terminalia arjuna (121) followed by Gmelina arborea (114) and Tectona grandis (95). The documented species were dominated by endemic flora (66.31%) and exotic flora (33.68%). Majority of the species (54) were of timber value, followed by food (50), fodder (36) and ethno-medicine (39). Based on the contribution to ecosystem services all the 95 species have the potential to sequest carbon followed by 46 species to provide beautification in the form of avenue/ornamental/roadside. The tree species richness and their potential ecosystem services documented in the present study can be a baseline study for further assessment of such landscapes and their significance under threatning environmental conditions.

Distribution of Honey and Pollen Forestry Trees Important to Honey Bee Along the Syrian Coast Using Geographic Information Systems

Distribution of Honey and Pollen Forestry Trees Important to Honey Bee Along the Syrian Coast Using Geographic Information Systems

Cryopreservation of Fagus crenata seeds: estimation of optimum moisture content for maintenance of seed viability by Bayesian modeling

Fagus crenata Blume is an important forestry tree species that plays a key biological role in natural forests. Because F. crenata forests are declining under global warming, the conservation of seed resources is necessary to maintain sustainable regeneration. We examined the capability of seed cryopreservation to achieve semi-permanent preservation of the F. crenata genetic resource. Seeds at 7%–26% moisture content (MC) exhibited greater than 64% viability, with developing radicles growing at 22 °C in 16 h photoperiods following chilling at 2 °C for 2 months. These seeds were then stored cryogenically at –170 °C for 6 months; cryopreservation at 26% MC reduced seed viability to 12%, whereas dry seeds (7%–14% MC) maintained viability and were comparable with seeds that had neither been dried nor cryopreserved. Drying seeds to 6% MC reduced viability to 47%; following cryopreservation, the viability of these seeds with such a low MC was 36%. Using a Bayesian model, we then determined that the optimal range of MC for the cryopreservation of F. crenata seeds was 9%–12%. We conclude that cryopreservation is feasible for the long-term storage of F. crenata seeds, drying of the seeds to the range of optimal MC retains high viability during cryogenic storage.

Comparative Study of Transpiration in Cooling Effect of Tree Species in the Atmosphere

Trees create microclimate under their crowns in comparison to the outside ambient atmosphere, which is a result of physical as well as physiological functions of the tree. The cooling produced by trees varies with species due to variation in several anatomical, structural and physiological attributes of the species. Transpiration is one of the most significant physiological functions performed by plants, which affects cooling produced by a tree under its shade. When solar energy impinges on the leaf, water emerges from its surface through transpiration taking the latent heat to convert it into water vapour. This leads to a rise in humidity of the atmosphere and reduction in temperature of the leaf. To remain leaf in equilibrium, it takes heat from the surrounding atmosphere resulting in reduction in temperature of surroundings. Since, transpiration takes place through stomata which are normally located on the ventral side of the leaf, this reduction in temperature is more experienced beneath the crown of the tree. Therefore, the present study was carried out to analyze the role of transpiration in cooling effect of five forestry tree species. The cooling produced by tree species under their shades has been found positively correlated to the transpiration rate whereas the rate of transpiration has responded positively to the ambient temperature and water conductance. However, no definite relationship has been found between frequency of open stomata and the rate of transpiration.

Comparative Study of Cooling under Shades of Some Forestry Tree Species with Respect to Ambient Temperatures

Trees create microclimate under their crowns in comparison to the outside ambient atmospheric temperature. Sun is the pivotal source of radiant energy reaching the earth atmosphere of which heat is more important than light. The radiant energy reaches the ground without any barricade whereas the tree crown impedes it in reaching the earth’s surface. During the day, when insolation impinges on tree crown, a portion of it is reflected back to the space, other portion is absorbed by the canopy increasing the temperature of leaves and the remaining part reaches the ground penetrating through the crown. Thus, a significant coolness is experienced under the shade of trees in comparison to open sunshine, with qualitative variations. The cooling produced by trees under their shades varies with species to species due to variation in several anatomical, structural and physiological attributes of the species. Climate is changing more rapidly prominently due to human activities especially indiscriminate felling of trees and it is feared that it will create problems on availability of energy, water and food security. Economic value takes over ecological benefits in selection of species in plantation programmes and this might have been due to the lack of scientific data about varying effectiveness of ecological services bestowed by different species. In the present study, an endeavor has been made to understand as to how a tree is integrated to the effects on atmosphere and responses to changing conditions with respect to differential cooling produced by five selected forestry tree species belonging to different categories. Analysis of data has come out with gradation of the sample species in respect to their cooling effect in the atmosphere in terms of yearly, quarterly, monthly and diurnal basis.

Removal of glucuronic acid from xylan is a strategy to improve the conversion of plant biomass to sugars for bioenergy

BackgroundPlant lignocellulosic biomass can be a source of fermentable sugars for the production of second generation biofuels and biochemicals. The recalcitrance of this plant material is one of the major obstacles in its conversion into sugars. Biomass is primarily composed of secondary cell walls, which is made of cellulose, hemicelluloses and lignin. Xylan, a hemicellulose, binds to the cellulose microfibril and is hypothesised to form an interface between lignin and cellulose. Both softwood and hardwood xylan carry glucuronic acid side branches. As xylan branching may be important for biomass recalcitrance and softwood is an abundant, non-food competing, source of biomass it is important to investigate how conifer xylan is synthesised.ResultsHere, we show using Arabidopsis gux mutant biomass that removal of glucuronosyl substitutions of xylan can allow 30% more glucose and over 700% more xylose to be released during saccharification. Ethanol yields obtained through enzymatic saccharification and fermentation of gux biomass were double those obtained for non-mutant material. Our analysis of additional xylan branching mutants demonstrates that absence of GlcA is unique in conferring the reduced recalcitrance phenotype. As in hardwoods, conifer xylan is branched with GlcA. We use transcriptomic analysis to identify conifer enzymes that might be responsible for addition of GlcA branches onto xylan in industrially important softwood. Using a combination of in vitro and in vivo activity assays, we demonstrate that a white spruce (Picea glauca) gene, PgGUX, encodes an active glucuronosyl transferase. Glucuronic acid introduced by PgGUX reduces the sugar release of Arabidopsis gux mutant biomass to wild-type levels indicating that it can fulfil the same biological function as native glucuronosylation.ConclusionRemoval of glucuronic acid from xylan results in the largest increase in release of fermentable sugars from Arabidopsis plants that grow to the wild-type size. Additionally, plant material used in this work did not undergo any chemical pretreatment, and thus increased monosaccharide release from gux biomass can be achieved without the use of environmentally hazardous chemical pretreatment procedures. Therefore, the identification of a gymnosperm enzyme, likely to be responsible for softwood xylan glucuronosylation, provides a mutagenesis target for genetically improved forestry trees.

Correlation between leaf size and hydraulic architecture in five compound-leaved tree species of a temperate forest in NE China

The divergence between simple and compound leaf form is a fundamental division in leaf architecture that has great impact on environmental adaptations of plants. Two hypotheses regarding the adaptive significance of compound leaf form have long been hypothesized: (1) it enables trees to have higher growth rates under favorable environmental conditions; (2) it contributes to better adaptation to seasonal and unpredictable drought stresses since dropping the whole leaf units could function as a protective mechanism of hydraulic segmentation and hence avoiding diebacks of the more carbon costly stems. These hypotheses, however, have not been firmly supported by mechanistic studies on the underlying physiology and more importantly the inter-specific variations within this functional group in relation to these two proposed hypotheses have largely been overlooked. In the present study, using a common garden setup we investigated the impact of leaf size, an important characteristic of leaf architecture, on xylem hydraulics and carbon economy of five commonly found sympatric compound-leaved tree species from a typical temperate forest of NE China. We specifically tested the hypotheses that larger compound leaf size would be associated with higher hydraulic conductance, increased efficiency of carbon assimilation and greater degree of hydraulic segmentation. Our results showed that the majority of the hydraulic resistance in shoots was allocated to leaf lamina (53–77% among the five species) and the compound leaf petiole only accounts for a small portion of the shoot hydraulic resistance (9–24%). Both stem hydraulic conductivity and whole-shoot hydraulic conductance showed strong positive correlations with compound leaf size contributing to significantly higher carbon assimilation efficiency in species with larger leaf sizes. The magnitude of water potential drop across transpiring leaves showed a strong positive correlation with leaf size resulting in less negative stem xylem water potential in species with larger leaf sizes, which supports our hypothesis that larger compound leaf enhances hydraulic segmentation. Our results also showed that the advantages associated with larger leaf size can be traded off by a greater susceptibility to freeze-thaw induced hydraulic dysfunction. Besides a deeper understanding of the environmental adaptation of compound-leaved tree species, these findings may contribute to a better utilization of this important type of trees in forestry.

Molecular Characterization of Arbuscular Mycorrhizal Fungi in an Agroforestry System Reveals the Predominance of Funneliformis spp. Associated with Colocasia esculenta and Pterocarpus officinalis Adult Trees and Seedlings.

Pterocarpus officinalis (Jacq.) is a leguminous forestry tree species endemic to Caribbean swamp forests. In Guadeloupe, smallholder farmers traditionally cultivate flooded taro (Colocasia esculenta) cultures under the canopy of P. officinalis stands. The role of arbuscular mycorrhizal (AM) fungi in the sustainability of this traditional agroforestry system has been suggested but the composition and distribution of AM fungi colonizing the leguminous tree and/or taro are poorly characterized. An in-depth characterization of root-associated AM fungal communities from P. officinalis adult trees and seedlings and taro cultures, sampled in two localities of Guadeloupe, was performed by pyrosequencing (GS FLX+) of partial 18S rRNA gene. The AM fungal community was composed of 215 operational taxonomic units (OTUs), belonging to eight fungal families dominated by Glomeraceae, Acaulosporaceae, and Gigasporaceae. Results revealed a low AM fungal community membership between P. officinalis and C. esculenta. However, certain AM fungal community taxa (10% of total community) overlapped between P. officinalis and C. esculenta, notably predominant Funneliformis OTUs. These findings provide new perspectives in deciphering the significance of Funneliformis in nutrient exchange between P. officinalis and C. esculenta by forming a potential mycorrhizal network.

Quantitative estimation of carbon stock and carbon sequestration in smallholder agroforestry farms of mango and Indian gooseberry in Rajasthan, India

Tree-based farming systems have the potential to sequester large quantities of carbon. An agroforestry system, promoted among small farmers in rural development projects in India, combines fruit and forestry trees with annual crops. As the carbon sequestration potential of this system has not been quantitatively estimated, a study was conducted on 25 orchards each of amla (Emblica officinalis) and mango (Mangifera indica) in two districts of Rajasthan, India. The orchards, aged between 7-14 years, were selected randomly and biomass accumulation of the trees was estimated using non-destructive allometric methods with quadrate sampling. The mean accumulated carbon in above-ground woody biomass of an amla tree was 0.05 t and that of mango was 0.04 t at an average age of 10 years. Similarly, the estimated carbon sequestered by multipurpose forestry trees growing along the border of the orchard was 0.012 t m2. Besides the above-ground biomass, the orchards also accumulated 8.1 t carbon ha-1 in the upper 15 cm of the soil. The study estimated that the total above and below-ground biomass in a 10 year old agroforestry farm having amla or mango with forestry trees contained 23 t ha-1 of carbon which was equivalent to 84.67 t CO2 ha-1.

Analysis of Exploitation of Forestry Biomass by Industrialization: Effect of Harvesting and Taxation

A control strategy for the conservation of forest biomass is proposed using the system of ordinary differential equation. For system dynamics, we have chosen four state variables in which first three stages are linked up to forest biomass via immature, semi-mature and mature trees and forth industrialization. It is assumed that industries harvest semi and mature phases of the forestry (trees) biomass. Analytically studied the local and global stability of steady state as well as the harvesting policy around the interior steady state. For conservation purpose, we have obtained optimal path considering tax as a control strategy to limit the harvest of trees. In particular, optimal control path is obtained using Pontryagin’s maximum principle. To corroborate the results, we have done numerical simulations for a different set of parameters and shown the various behavior of the system. Further, we have likewise noticed that there are certain parameters which are extremely sensitive to the coexistence state. Sensitivity analysis is done using normalized forward sensitivity index.

Developing publicly acceptable tree health policy: public perceptions of tree-breeding solutions to ash dieback among interested publics in the UK

The UK needs to develop effective policy responses to the spread of tree pathogens and pests. This has been given the political urgency following the media and other commentary associated with the arrival of a disease that causes ‘dieback’ of European Ash (Fraxinus excelsior) - a tree species with deep cultural associations. In 2014 the UK government published a plant biosecurity strategy and linked to this invested in research to inform policy. This paper reports the findings of a survey of informed UK publics on the acceptability of various potential strategies to deal with ash dieback, including “no action”. During the summer of 2015, we conducted a face-to-face survey of 1152 respondents attending three major countryside events that attract distinct publics interested in the countryside: landowners & land managers; naturalists and gardeners.We found that UK publics who are likely to engage discursively and politically (through letter writing, petitions etc.) with the issue of ash dieback a) care about the issue, b) want an active response, c) do not really distinguish between ash trees in forestry or ecological settings, and d) prefer traditional breeding solutions. Further that e) younger people and gardeners are open to GM breeding techniques, but f) the more policy-empowered naturalists are more likely to be anti-GM. We suggest that these findings provide three ‘steers’ for science and policy: 1) policy needs to include an active intervention component involving the breeding of disease-tolerant trees, 2) that the development of disease tolerance using GM-technologies could be part of a tree-breeding policy, and 3) there is a need for an active dialogue with publics to manage expectations on the extent to which science and policy can control tree disease or, put another way, to build acceptability for the prospect that tree diseases may have to run their course.

Extraction of Genomic DNA from Inner Bark of Cedrus deodara (Roxb.) G. Don for RAPD Study

Genomic DNA extraction from forestry tree species require young leaf samples to obtain high-quality DNA for molecular based study. For some study, leaf samples must be collected from remote areas and are difficult to transport long distances. We developed alternative method of DNA extraction from inner bark of Cedrus deodara. We used 2.5% PVP for removal of phenolic compound and apply high concentration of sodium chloride to removes polysaccharides. Extracted DNA gives positive amplification with PCR using random amplification of polymorphic DNA (RAPD) markers.

Combined effects of climate, habitat, and disturbance on seedling establishment of Pinus pinaster and Eucalyptus globulus

The natural expansion of forestry trees into habitats outside plantations is a concern for managers and conservationists. We studied seedling emergence and survival of the two main forestry species in Portugal: Eucalyptus globulus (exotic) and Pinus pinaster (native); using a seed addition experiment. Our main objective was to evaluate the combined effects of climate (mild-summer and warm-summer climate), habitat (oak forest and shrubland), and disturbance (vegetation removal and non-disturbance) on the seedling establishment of species in semi- and natural habitats. Furthermore, we tested the effect of the “sowing season” (autumn and spring) on seedling emergence and survival. Overall, seedling establishment of both species was enhanced by light and water. However, we found important interactions among climate, habitat, and disturbance on both species’ emergence and survival. The differences between habitats were more evident in the mild-summer climate than in the warm-summer climate. Our results also suggested that seedling survival may be enhanced by shrub cover in drier conditions (warm-summer climate). Eucalyptus globulus appears more sensitive to drought and disturbance changes than P. pinaster. In shrublands and mild-summer climate conditions, disturbance especially promoted E. globulus seedling establishment, while the forest canopy and the shade appeared to control it in both climatic conditions. After the first summer life, very low seedling survival was observed in both species, although the colonization of new areas appeared to be more limited for E. globulus. Our study suggests that climate conditions influence the effect (direction and intensity) of habitat and disturbance (plant–plant interactions) on seedling survival. Thus, the effect of light availability (forest canopy) and disturbance (vegetation removal) on these species establishment is climate context-dependent. This study presents very useful information to understand future shifts in these species distribution and has direct applications for the management of natural establishment outside the planted areas, and the management of the understorey to favor forest regeneration or limit forest colonization.

The Use of Auxin Quantification for Understanding Clonal Tree Propagation

Qualitative and quantitative hormone analyses have been essential for understanding the metabolic, physiological, and morphological processes that are influenced by plant hormones. Auxins are key hormones in the control of many aspects of plant growth and development and their endogenous levels are considered critical in the process of adventitious root induction. Exogenous auxins are used extensively in the clonal propagation of tree species by cuttings or tissue culture. Understanding of auxin effects has advanced with the development of increasingly accurate methods for auxin quantification. However, auxin analysis has been challenging because auxins typically occur at low concentrations, while compounds that interfere with their detection often occur at high concentrations, in plant tissues. Interference from other compounds has been addressed by extensive purification of plant extracts prior to auxin analysis, although this means that quantification methods have been limited by their expense. This review explores the extraction, purification, and quantification of auxins and the application of these techniques in developing improved methods for the clonal propagation of forestry trees.

Highlighting the Need for Systems-Level Experimental Characterization of Plant Metabolic Enzymes.

The biology of living organisms is determined by the action and interaction of a large number of individual gene products, each with specific functions. Discovering and annotating the function of gene products is key to our understanding of these organisms. Controlled experiments and bioinformatic predictions both contribute to functional gene annotation. For most species it is difficult to gain an overview of what portion of gene annotations are based on experiments and what portion represent predictions. Here, I survey the current state of experimental knowledge of enzymes and metabolism in Arabidopsis thaliana as well as eleven economically important crops and forestry trees – with a particular focus on reactions involving organic acids in central metabolism. I illustrate the limited availability of experimental data for functional annotation of enzymes in most of these species. Many enzymes involved in metabolism of citrate, malate, fumarate, lactate, and glycolate in crops and forestry trees have not been characterized. Furthermore, enzymes involved in key biosynthetic pathways which shape important traits in crops and forestry trees have not been characterized. I argue for the development of novel high-throughput platforms with which limited functional characterization of gene products can be performed quickly and relatively cheaply. I refer to this approach as systems-level experimental characterization. The data collected from such platforms would form a layer intermediate between bioinformatic gene function predictions and in-depth experimental studies of these functions. Such a data layer would greatly aid in the pursuit of understanding a multiplicity of biological processes in living organisms.

Differences in physiological responses to infection by Ceratocystis tsitsikammensis , a native ophiostomatoid pathogen, between a native forest and an exotic forestry tree in South Africa

The native forest-tree pathogen Ceratocystis tsitsikammensis infects native trees (e.g. Virgilia divaricata) and Acacia mearnsii, an invasive alien and important forestry tree in South Africa. We explored the physiological effects of infection by this fungus on these two tree species, within the context of the Biotic Resistance Hypothesis (BRH). The effects of infection on physiological and resource capture parameters were measured, in conjunction with lesion length. Infected V. divaricata trees changed their N economy by relying more on soil derived N and less on biological nitrogen fixation. Infected A. mearnsii trees altered their biomass allocation into below ground investments. The species responded differently to infection, hence it was not clear which was most negatively affected. Results do support numerous studies that base tests of pathogenicity on lesion length. These results hold important conservation and economic relevance as A. mearnsii is both an invasive tree species and a forestry tree.