Time filter

Source Type

Aracruz, Brazil

Eucalyptus grandis is one of the most popular species to use as raw material for pulp production in Brazil, as it provides excellent pulping, bleaching and papermaking results. The main objective of this study is to examine the quality of wood and pulp from a clone of Eucalyptus grandis, at age 4 years approximately, planted in three different soils, two of which being low fertility and one being a superior fertility soil, and their reflections on wood quality and pulping results. Chemical analyses of the soils followed guidelines developed by Raij et al. (2001), while physical and chemical properties of the wood followed ABTCP, TAPPI and ABNT standards. Chemical analyses of the soils pointed to lower fertility in Fazenda Limeira and Fazenda Tapera Queimada as opposed to higher fertility in Fazenda Mendes União. Results revealed stronger tendencies for the stand grown in the less fertile soils (Fazenda Limeira and Fazenda Tapera Queimada) in comparison to the stand grown in more fertile soil (Fazenda Mendes União) as to: higher wood and bark basic density, lower height and dry matter content, higher bark content, lower extractives content and higher holocellulose content, higher total and screened yields from pulping, lower specific wood consumption/t of pulp, and higher tear and tensile indices at low refining levels. Source

Hakamada R.,University of Sao Paulo | Giunti Neto C.,Fibria | de Lemos C.C.,International Paper Do Brazil | Silva S.R.,Brazilian Agricultural Research Corporation Embrapa | And 3 more authors.
Southern Forests | Year: 2016

Leaf area index (LAI) is a key ecophysiological parameter in forest stands because it characterises the interface between atmospheric processes and plant physiology. Several indirect methods for estimating LAI have been developed. However, these methods have limitations that can affect the estimates. This study aimed to evaluate the accuracy and applicability of a visual method for estimating LAI in clonal Eucalyptus grandis × E. urophylla plantations and to compare it with hemispherical photography, ceptometer and LAI-2000® estimates. Destructive sampling for direct determination of the actual LAI was performed in 22 plots at two geographical locations in Brazil. Actual LAI values were then used to develop a field guide with photographic images representing an LAI range of 1.0–5.0 m2 m−2 (leaf area/ground area). The visual LAI estimation guide was evaluated with 17 observers in the field. The average difference between actual LAI and visual LAI estimation was 12% and the absolute difference between the two methods was less than or equal to 0.5 m2 m−2 in 77% of plots. Pearson’s correlation coefficients were high between actual LAI and hemispherical photographs (0.8), visual estimation (0.93) and LAI-2000® (0.99) and low for the ceptometer (0.18). However, absolute values differed among methods, with the average difference between the actual and estimated LAI of [12]% for visual estimation, 28% for the LAI-2000®, 37% for the ceptometer and −43% for hemispherical photographs. The LAI-2000® and ceptometer overestimated LAI in all plots, whereas hemispherical photographs underestimated the values in all measurements, showing that these methods need calibration to be used. No differences were observed between actual LAI and visual estimates across stand ages of 2–8 years and LAI of 1.5–5.3 m2 m−2 (P > 0.05). The results show that visual estimation of LAI in Eucalyptus stands is a practical method that is unaffected by atmospheric characteristics and can be used on an operational scale. © 2016 NISC (Pty) Ltd Source

Pegoraro R.F.,State University of Montes Claros | Silva I.R.,Federal University of Vicosa | Novais R.F.,Federal University of Vicosa | Barros N.F.,Federal University of Vicosa | Fonseca S.,Fibria
Revista Arvore | Year: 2013

The study aimed to evaluate the content of phenols derived from lignin, carbohydrates, amino sugars, the stage of decomposition of compounds and the relative contribution of plant-and microbialderived compounds to the soil organic matter (SOM) in the conventional and fertirrigated till age of eucalyptus. Samples of litter and soil (Ultisol) were taken from two tillage systems (conventional and fertirrigated) at two collection sites (line and between-line) with three replications. It was evaluated the litter production, content of total organic C (TOC), total N (TN), lignin and phenols-derived lignin and its Ac/Alratio, carbohydrates and their hexose/pentose ratio, amino sugars and the glucosamine/muramic acid ratio in the soil. The cultivation of eucalyptus in fertirrigated system promoted higher litter fall, reduced the carbohydrate content and maintained the content of lignin in the litter in comparison to the conventional system. In soil, the greater accumulation of the litter (22%) in fertirrigated system increased the contents of carbohydrates, lignin and amino sugars, mainly in the between-lines position. The hexoses/pentoses ratio also increased, indicating a greater presence of compounds of microbial origin. Among the compounds of microbial origin, a larger abundance of glucosamine was observed, indicating a greater contribution of fungal to the SOM formation under fertirrigated cultivation. Source

Almeida A.C.,CSIRO | Siggins A.,CSIRO | Batista T.R.,Fibria | Beadle C.,CSIRO | And 3 more authors.
Forest Ecology and Management | Year: 2010

In the wet tropics, near the Atlantic Coast of Brazil, drought may reduce plantation yields by as much one-third over a six-to-seven-year rotation. For land owners, annual variation in production cannot be estimated with empirical models. In this paper, we examine whether the process-based growth model, 3-PG is sufficiently sensitive to climatic variation to provide a virtual record of changes in growing stock across 180,000 ha eucalypt plantation estate. We first mapped variation in climate and soil properties, and then ran simulations for the current planted forest with ages varying from one to seven years. Model predictions of stand volume and mean tree diameter agreed closely with measurements acquired on 60 reference plots monitored over the test period; the prediction of mean annual increment (MAI) was less reliable. Available soil water (ASW) and leaf area index (LAI) were also measured and compared with the model estimations. Vapour pressure deficit (VPD) and ASW accounted for most of the variation in yields. We conclude that this spatial modelling approach offers a reasonable alternative to extensive ground surveys, particularly when climatic variation extends beyond the historical average for a region. Crown Copyright © 2009. Source

e Silva C.S.J.,Fibria | de Oliveira A.D.,Federal University of Lavras | Coelho Jr. L.M.,Instituto Agronomico Do Parana | Scolforo J.R.S.,Federal University of Lavras | de Souza A.N.,University of Brasilia
Cerne | Year: 2014

The general objective of this paper was studying the economic feasibility and determining the economic rotation of candeia planting at various spacings under risky conditions. The study was conducted from an experimental planting of candeia consisting of four spacings (1.5 x 1.5 m, 1.5 x 2.0 m, 1.5 x 2.5 m and 1.5 x 3.0 m) for which the cash flows related to the different cutting ages were obtained. For the risk analysis the Monte Carlo method was used, its having the Equivalent Annual Value (EAV) as the output variable (output) and as input variables (sources of uncertainty) the probability distributions concerning the price of the seedlings, land and wood, the harvest cost, interest rates and timber production. The simulation constituted in the doing of 50,000 iterations from where the information necessary to the analyses was extracted. It was concluded that the 1.5 x 3.0 m spacing was the most economically viable and presented a lower risk level than the other spacings. The economic rotation was 12, 13, 13 and 15 years for the spacings 1.5 x 3.0 m, 1.5 x 2.5 m, 1.5 x 2.0m and 1.5 x 1.5m, respectively. Information obtained about the economic risks involved in planting candle serve as a tool to aid in making decisions regarding new plantings of this species and also as a basis for future experiments with the same, seeking to improve its culture. Source

Discover hidden collaborations