Aboveground interactions and productivity in mixed-species plantations of Acacia mearnsii and Eucalyptus globulus

2004 ◽  
Vol 34 (3) ◽  
pp. 686-694 ◽  
Author(s):  
Jürgen Bauhus ◽  
Aaron P van Winden ◽  
Adrienne B Nicotra
Keyword(s):  
Eucalyptus Globulus ◽  
Net Photosynthesis ◽  
Stem Volume ◽  
Niche Separation ◽  
Mixed Species ◽  
Acacia Mearnsii ◽  
Replacement Series ◽  
Crown Volume ◽  
Lower Light ◽  
Productivity Gains

This study compared productivity in mixed-species plantations of Eucalyptus globulus ssp. pseudoglobulus (Naudin ex Maiden) Kirkpatr. and Acacia mearnsii de Wild with pure stands of each species and investigated how this might be explained by canopy stratification between species and changes in leaf characteristics of eucalypts. Investigations were carried out at a trial using the replacement series design, which consisted of the following combinations: 100% eucalypts (100%E), 75% eucalypts + 25% acacia (75%E:25%A), 50% eucalypts + 50% acacia (50%E:50%A), 25% eucalypts + 75% acacia (25%E:75%A), and 100% acacia (100%A). At 9.5 years, stem volume and biomass were highest in 50%E:50%A treatments. Canopy stratification occurred in all mixtures, with acacias in the lower and eucalypts in the upper canopy stratum. This and the increasing canopy light interception with increasing proportion of acacia in the mixture indicated that A. mearnsii is substantially more shade tolerant than E. globulus. Midcanopy foliage of E. globulus in the 50%E:50%A mixture had higher foliage nitrogen (N) but lower phosphorus (P) concentrations and lower light-saturated net photosynthesis rates (Amax) than those in the 100%E treatment. In addition, similar relationships between eucalypt crown volume and stem biomass across treatments indicated that eucalypt crowns were not more efficient in mixture. Our study indicates that the productivity gains in these mixtures may be partially attributable to aboveground niche separation between species.

Nutrient cycling in a mixed-species plantation of Eucalyptus globulus and Acacia mearnsii

2005 ◽  
Vol 35 (12) ◽  
pp. 2942-2950 ◽  
Author(s):  
David I Forrester ◽  
Jürgen Bauhus ◽  
Annette L Cowie
Keyword(s):  
Nutrient Cycling ◽  
Biomass Production ◽  
Aboveground Biomass ◽  
Eucalyptus Globulus ◽  
N Availability ◽  
Species Replacement ◽  
Mixed Species ◽  
Acacia Mearnsii ◽  
Replacement Series ◽  
Silvicultural System

A doubling of aboveground biomass production has been observed in mixtures of Eucalyptus globulus Labill. and Acacia mearnsii de Wildeman when compared with monocultures after 11 years of growth. This study examined to what extent increased nitrogen (N) availability and accelerated rates of nutrient cycling may contribute to increased growth in mixtures. Monocultures of E. globulus (E) and A. mearnsii (A) and mixtures of these species were planted in a species replacement series: 100% E, 75% E + 25% A, 50% E + 50% A, 25% E + 75% A, and 100% A. Litterfall mass increased with aboveground biomass production and was highest in 50:50 mixtures and lowest in monocultures. Owing to higher N concentrations of A. mearnsii litter, N contents of annual litterfall were at least twice as high in stands containing A. mearnsii (32-49 kg·ha–1·year–1) as in E. globulus monocultures (14 kg·ha–1·year–1). Stands with A. mearnsii also cycled higher quantities of phosphorus (P) in annual litterfall than E. globulus monocultures. This study demonstrated that mixing A. mearnsii with E. globulus increased the quantity and rates of N and P cycled through aboveground litterfall when compared with E. globulus monocultures. Thus, mixed-species plantations appear to be a useful silvicultural system to improve nutrition of eucalypts without fertilization.

Aboveground and belowground interactions in mixed plantations of Eucalyptus globulus and Acacia mearnsii

2000 ◽  
Vol 30 (12) ◽  
pp. 1886-1894 ◽  
Author(s):  
J Bauhus ◽  
P K Khanna ◽  
N Menden
Keyword(s):  
Eucalyptus Globulus ◽  
Root Architecture ◽  
Fine Root ◽  
Tree Height ◽  
Stem Volume ◽  
Niche Separation ◽  
N Fixation ◽  
Acacia Mearnsii ◽  
N Nutrition ◽  
Mixed Plantations

This study investigated whether increased productivity in mixed plantations of Eucalyptus globulus Labill. and Acacia mearnsii de Wild when compared with monocultures could be explained by niche separation of the fine-root systems. For this purpose fine-root architecture, nutrient concentration, and fine-root distribution were examined in two horizons (0-15 and 15-30 cm) of mixed and pure stands. Investigations were carried out in 6.5-year-old plantations consisting of 100% eucalypts, 75% eucalypts + 25% acacia, 50% eucalypts + 50% acacia, 25% eucalypts + 75% acacia, and 100% acacia. Aboveground the two species interacted synergistically. Stem volume and tree height was highest in the 50:50 mixtures. For acacias, intraspecific competition was stronger than interspecific competition with eucalypts. Fine-root biomass and length density were similar for all species combinations, and there was no synergistic effect. The vertical distribution of fine roots and fine-root architecture were similar for acacias and eucalypts. This indicated that soil exploitation strategies may be similar, which can result in strong competition for soil resources. Fine-root nitrogen concentrations of eucalypts were highest in the 50:50 mixture. Improved productivity of mixtures appears to be a result of both canopy stratification and improved N nutrition of eucalypts through N fixation by acacias.

Growth dynamics in a mixed-species plantation of Eucalyptus globulus and Acacia mearnsii

2004 ◽  
Vol 193 (1-2) ◽  
pp. 81-95 ◽  
Author(s):  
David I Forrester ◽  
Jürgen Bauhus ◽  
Partap K Khanna
Keyword(s):  
Eucalyptus Globulus ◽  
Growth Dynamics ◽  
Mixed Species ◽  
Acacia Mearnsii

Carbon allocation in a mixed-species plantation of Eucalyptus globulus and Acacia mearnsii

2006 ◽  
Vol 233 (2-3) ◽  
pp. 275-284 ◽  
Author(s):  
David I. Forrester ◽  
Jürgen Bauhus ◽  
Annette L. Cowie
Keyword(s):  
Eucalyptus Globulus ◽  
Carbon Allocation ◽  
Mixed Species ◽  
Acacia Mearnsii

scholarly journals ARTIFICIAL NEURAL NETWORKS (ANN) FOR HEIGHT ESTIMATION IN A MIXED-SPECIES PLANTATION OF Eucalyptus globulus LABILL AND Acacia mearnsii DE WILD

2021 ◽  
Vol 45 ◽  
Author(s):  
Gustavo Martins Soares ◽  
Luciana Duque Silva ◽  
Antonio Rioyei Higa ◽  
Augusto Arlindo Simon ◽  
Jackson Freitas Brilhante de São José
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Eucalyptus Globulus ◽  
Growth Patterns ◽  
Mixed Species ◽  
Acacia Mearnsii ◽  
Height Estimation ◽  
R Project ◽  
Artificial Neural ◽  
Stand Attributes

ABSTRACT The objective of this study is to evaluate the fit of Artificial Neural Networks (ANN) for height estimation and evaluation of the effects of consortium in a mixed-species plantation of Eucalyptus globulus (E) and Acacia mearnsii (A). The experiment was installed in 2005, on two farms in the municipality of Piratini - RS, where was planted the species Eucalyptus globulus (E) and Acacia mearnsii (A), in monoculture and mixed in simple lines (50%E:50%A - SL), and double lines (50%E:50%A - DL). The training and evaluation of the networks were made in R-project with the package neuralnet. All ANNs, from the simplest to the most complex, showed high values for Rŷy and low for Syx, BIAS and RMSE, with superior results in ANN 3, 4, and 6, which demonstrates that the information of DBHmin, DBHmean, and DBHmax were important stand attributes. Furthermore, the ANNs were able to capture the different growth patterns shown by the species in the different forms of consortiums, therefore is indicated for the height estimation in monocultures and mixed plantations of Eucalyptus globulus and Acacia mearnsii, and only one ANN would be necessary to represent the entire population.

Does the addition of litter from N-fixing Acacia mearnsii accelerate leaf decomposition of Eucalyptus globulus?

2007 ◽  
Vol 55 (5) ◽  
pp. 576 ◽  
Author(s):  
W. Xiang ◽  
J. Bauhus
Keyword(s):  
Species Interactions ◽  
Eucalyptus Globulus ◽  
N Cycling ◽  
Decomposition Rates ◽  
Mixed Species ◽  
Acacia Mearnsii ◽  
N Loss ◽  
Mixed Stands ◽  
Mixed Litter ◽  
Loss Of Mass

Nutrient cycling in mixed-species plant communities may be enhanced in comparison to what might be expected from the component species. In this study, we investigated (1) whether the admixing of nitrogen-rich litter from Acacia mearnsii can accelerate the decomposition of Eucalyptus globulus leaf litter and (2) whether eucalypt litter originating from mixed stands with acacias decomposes faster than litter from pure eucalypt stands. To address the first question, pure and mixed litter was incubated in the laboratory for 110 days at 25°C in the following proportions: 100%E, 75%E : 25%A, 50%E : 50%A, 25%E : 75%A and 100%A, where %E and %A refers to the proportion of eucalypt and acacia in the microcosms, respectively. Since mass loss and N loss of litter in the 50 : 50 mixture was higher than for pure eucalypt but not higher than for acacia, it appears that acacia litter accelerated decomposition of eucalypt litter but not vice versa. Decomposition rates increased with N concentration in the combined litters up to 1.1% N, above that point it remained constant. To address the second question, eucalypt litter from pure and mixed stands was incubated in microcosms. The loss of mass, N and P after 110 days was not different for eucalypt litter originating from mixed (75E : 25A, 50E : 50A, 25E : 75A) and pure (100E) plantations. Together, these studies suggest that admixture of A. mearnsii to E. globulus has the potential to accelerate decomposition and N cycling, and that the species interactions are most pronounced in the 50 : 50 mixture. Mixing of the two species in plantations has so far had no influence on the decomposability of eucalypt litter.

scholarly journals Analytical approaches for modeling tree crown volume in black wattle (Acacia mearnsii De Wild.) stands

2016 ◽  
Vol 11 (49) ◽  
pp. 4979-4989
Author(s):  
C. Cadori Guilherme ◽  
R. Sanquetta Carlos ◽  
Pellico Netto Sylvio ◽  
Behling Alexandre ◽  
Costa Junior Sergio ◽  
...  
Keyword(s):  
Tree Crown ◽  
Acacia Mearnsii ◽  
Crown Volume ◽  
Black Wattle ◽  
Analytical Approaches

scholarly journals OC kappa increases in the levels of glucose, trehalose, TOR-P and transcripts encoding proteins involved in photosynthesis, and basal and secondary metabolisms in Eucalyptus globulus

2018 ◽  
Author(s):  
Silvia Saucedo ◽  
Alberto González ◽  
Melissa Gómez ◽  
Rodrigo A Contreras ◽  
Daniel Laporte ◽  
...  
Keyword(s):  
Secondary Metabolism ◽  
Eucalyptus Globulus ◽  
Net Photosynthesis ◽  
Defense Responses ◽  
Water Control ◽  
S6 Kinase ◽  
Expression Of Genes ◽  
Oscillatory Pattern ◽  
Glucose Accumulation ◽  
Metabolism Enzyme

Oligo-carrageenan (OC) kappa increases net photosynthesis, and basal and secondary metabolism enzyme activities in Eucalyptus globulus trees. Here, trees were sprayed on leaves with water (control) or with OC kappa 1 mg ml-1, once a week, four times in total, and cultivated for 17 additional weeks (21 weeks in total). Height, level of glucose, trehalose, TOR phosphorylated in Ser2448 (TOR-P) and transcripts encoding TOR and S6 kinase (S6K) as well as the level of transcripts encoding proteins and enzymes involved in glucose accumulation, photosynthesis, C, N and S assimilation, and synthesis of phenylpropanoid compounds (PPCs) and terpenes were determined. Treated trees showed an increase in height of 105% compared to controls at week 21. Treated trees showed an increase in glucose and trehalose level having an oscillatory pattern with maximal levels for glucose at week 1, 9-11 and 17-19, and for trehalose at weeks 1-3, 5, 8-9, 12, 15-16 and 18-21. TOR-P showed increases from week 1 until the end of the experiment with peaks at weeks 2, 6, 12 and 16. The level of tor transcripts showed peaks at weeks 3, 6, 10-11 and 13 whereas the level of s6k transcripts remained unchanged. In addition, transcripts encoding proteins involved in photosynthesis, and enzymes involved in glucose accumulation, C, N and S assimilation, and synthesis of secondary metabolites showed an oscillatory pattern with increases mainly at weeks 3-4, 5-6, 10-11, and in some cases at weeks 13-14 and 16-18. Thus, the increases in trehalose levels better correlate with increases in TOR-P and transcript levels. Therefore, OC kappa induced an increase in the levels of glucose, trehalose, TOR-P and expression of genes involved in photosynthesis, and basal and secondary metabolism which may explain, at least in part, the increase in growth and defense responses in E. globulus trees.

scholarly journals Compatible Taper and Stem Volume Equations for Five Pine Species in Mixed-Species Forests in Mexico

2019 ◽  
Vol 65 (5) ◽  
pp. 602-613
Author(s):  
Gerónimo Quiñonez-Barraza ◽  
Dehai Zhao ◽  
Héctor Manuel De los Santos-Posadas
Keyword(s):  
Volume Ratio ◽  
Stem Volume ◽  
Volume Data ◽  
Stem Height ◽  
White Pine ◽  
Mixed Species ◽  
Cumulative Volume ◽  
Volume Equations ◽  
Better Than ◽  
Pine Species

Abstract Ten systems of compatible taper and outside-bark volume equations derived from upper-height-based volume ratio equations were compared with a used segmented-stem system of compatible taper and volume equations. All the systems were simultaneously fitted to cumulative volume data and taper data for Arizona pine, Aztec pine, Durango pine, Mexican white pine, and Smooth-leaved pine species in naturally regenerated mixed-species forests in Mexico. The systems derived from volume ratio equations performed better than the segmented-stem system for most species. The resultant top systems might be easier to implement than the segmented-stem system for predicting upper-stem height, upper-stem diameter, merchantable volume, and total stem volume for considered species.

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