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 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.

The relative competitiveness of atrazine susceptible and resistant populations of Chenopodium album and C. strictum

1981 ◽  
Vol 59 (5) ◽  
pp. 689-693 ◽  
Author(s):  
S. I. Warwick ◽  
L. Black
Keyword(s):  
Biomass Production ◽  
Aboveground Biomass ◽  
Competitive Ability ◽  
Chenopodium Album ◽  
Dry Weight ◽  
Replacement Series ◽  
Susceptible Population ◽  
Resistant Population ◽  
Reproductive Biomass ◽  
Susceptible Populations

The total aboveground biomass and reproductive dry weight of one atrazine resistant and one susceptible population from southern Ontario of each of two species of Chenopodium, C. album and C. strictum, were compared. The comparison was made between plants grown under both noncompetitive and competitive conditions. Results from a spaced noncompetitive trial provided evidence for: (1) greater total and reproductive biomass production and earlier flowering of resistant and susceptible populations of C. album as compared with both populations of C. strictum, (2) greater aboveground total and reproductive biomass production of the susceptible population of C. album as compared with the resistant population, and (3) greater total aboveground biomass production (but similar reproductive biomass) of the susceptible population of C. strictum as compared with the resistant population. Results from the competition trials (i.e., plants grown in a de Wit replacement series), provided evidence for inter- and intra-specific differences in competitive ability: (1) the susceptible population of C. album was found to be more competitive than the susceptible population of C. strictum, (2) the susceptible population of C. album was a superior competitor to the resistant population, and (3) the resistant and susceptible populations of C. strictum appeared to be equally competitive.

Aboveground biomass production and nutrient accumulation on postharvested white spruce sites in interior Alaska

1993 ◽  
Vol 23 (6) ◽  
pp. 1233-1239 ◽  
Author(s):  
David Paré ◽  
Keith Van Cleve
Keyword(s):  
Nutrient Cycling ◽  
Biomass Production ◽  
Aboveground Biomass ◽  
Nutrient Content ◽  
White Spruce ◽  
Trembling Aspen ◽  
Total N ◽  
Clear Cutting ◽  
Aboveground Production ◽  
Spruce Stands

Nutrient content and biomass of aboveground annual production, and nutrient content of total aboveground biomass, of 14-year-old assemblages of plants developing on harvested white spruce (Piceaglauca (Moench) Voss) sites were estimated by vegetation harvesting and compared with values previously measured in mature white spruce stands. The aboveground biomass production of 14-year-old regenerating trembling aspen (Populustremuloides Michx.) clumps was 3 times higher than the aboveground production of mature white spruce stands, while the aboveground production of other regenerating communities was lower or equivalent to the production of mature white spruce. However, the nutrient content of aboveground current biomass was greater in all regenerating communities than in mature white spruce stands, except on regenerating sites where the forest floor was absent. The amount of nutrient incorporated in current aboveground biomass was 5 times greater in trembling aspen clumps than in mature white spruce stands. Furthermore, the total N, P, and K content of aboveground vegetation corresponded, in 14-year-old trembling aspen clumps, to a value that ranged from 50 to 109% of the amount found in the aboveground biomass of mature white spruce forests, while this value ranged from 4 to 14% on other regeneration types. Trembling aspen and balsam poplar (Populusbalsamifera L.) both showed the greatest concentrations of N and P in foliar litter fall. These observations suggest that the development of a trembling aspen clump after clear-cutting contributes to the acceleration of nutrient cycling. On the other hand, the development of herbaceous communities during the same period after clear-cutting was accompanied by much lower nutrient cycling rates in the aboveground portion of the vegetation.

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.

scholarly journals Aboveground biomass production in an irrigation and fer- tilization field experiment with Eucalyptus globulus

1989 ◽  
Vol 46 (Supplement) ◽  
pp. 526s-528s ◽  
Author(s):  
C. Araújo ◽  
J. S. Pereira ◽  
L. Leal ◽  
M. Tomé ◽  
J. Flower-Ellis ◽  
...  
Keyword(s):  
Field Experiment ◽  
Biomass Production ◽  
Aboveground Biomass ◽  
Eucalyptus Globulus

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 Response of water fluxes and biomass production to climate change in permanent grassland soil ecosystems

2021 ◽  
Vol 25 (12) ◽  
pp. 6087-6106
Author(s):  
Veronika Forstner ◽  
Jannis Groh ◽  
Matevz Vremec ◽  
Markus Herndl ◽  
Harry Vereecken ◽  
...  
Keyword(s):  
Climate Change ◽  
Elevated Temperature ◽  
Biomass Production ◽  
Aboveground Biomass ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Actual Evapotranspiration ◽  
Water Fluxes ◽  
Permanent Grassland ◽  
Experimental Approaches

Abstract. Effects of climate change on the ecosystem productivity and water fluxes have been studied in various types of experiments. However, it is still largely unknown whether and how the experimental approach itself affects the results of such studies. We employed two contrasting experimental approaches, using high-precision weighable monolithic lysimeters, over a period of 4 years to identify and compare the responses of water fluxes and aboveground biomass to climate change in permanent grassland. The first, manipulative, approach is based on controlled increases of atmospheric CO2 concentration and surface temperature. The second, observational, approach uses data from a space-for-time substitution along a gradient of climatic conditions. The Budyko framework was used to identify if the soil ecosystem is energy limited or water limited. Elevated temperature reduced the amount of non-rainfall water, particularly during the growing season in both approaches. In energy-limited grassland ecosystems, elevated temperature increased the actual evapotranspiration and decreased aboveground biomass. As a consequence, elevated temperature led to decreasing seepage rates in energy-limited systems. Under water-limited conditions in dry periods, elevated temperature aggravated water stress and, thus, resulted in reduced actual evapotranspiration. The already small seepage rates of the drier soils remained almost unaffected under these conditions compared to soils under wetter conditions. Elevated atmospheric CO2 reduced both actual evapotranspiration and aboveground biomass in the manipulative experiment and, therefore, led to a clear increase and change in seasonality of seepage. As expected, the aboveground biomass productivity and ecosystem efficiency indicators of the water-limited ecosystems were negatively correlated with an increase in aridity, while the trend was unclear for the energy-limited ecosystems. In both experimental approaches, the responses of soil water fluxes and biomass production mainly depend on the ecosystems' status with respect to energy or water limitation. To thoroughly understand the ecosystem response to climate change and be able to identify tipping points, experiments need to embrace sufficiently extreme boundary conditions and explore responses to individual and multiple drivers, such as temperature, CO2 concentration, and precipitation, including non-rainfall water. In this regard, manipulative and observational climate change experiments complement one another and, thus, should be combined in the investigation of climate change effects on grassland.

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