Time filter

Source Type

Belo Oriente, Brazil

Ribeiro R.N.,CENIBRA | Muniz E.S.,Klabin | Won Park S.,University of Sao Paulo
O Papel | Year: 2013

This paper aims to make an economic evaluation of the results already achieved through implementation of Advanced Process Control (APC) in the pulp and paper industries. For this, we firstly describe some basic concepts, and then some cases of practical applications that have reported good outcomes are cited. Companies have invested in this technology, and there are many applications already in operation. It is worth to discuss now, after the euphoria of the initial results, what effectively are the outcomes achieved over the past years and, also, how to keep them in full control capability, promoting the appropriate maintenance actions for the effects initially achieved be improved over its use.

Gatto A.,Tecnico do Ministerio do Meio Ambiente | de Barros N.F.,Federal University of Vicosa | Novais R.F.,Federal University of Vicosa | da Silva I.R.,Federal University of Vicosa | And 3 more authors.
Revista Brasileira de Ciencia do Solo | Year: 2010

Eucalypt is the main commercial forest species in Brazil, but very little information is available in the literature on the amount of carbon stored in the soil and in the biomass of these forest stands. The main objective of this study was to estimate the amount of soil-stored carbon (SSC) of eucalypt plantations and determine soil and climate characteristics that influence SSC. The study was carried out in the Central-Eastern region of Minas Gerais State, Brazil, in five micro-regions (CO, RD, SB, SA, and VI) with varying soil and climatic conditions. Soil carbon was determined to a depth of 100 cm. Carbon in the forest floor was estimated by allometric equations. The carbon stored in the soil-plant system differed among micro-regions and soil classes. SSC ranged from 183.1 t ha-1 in Red Latosol to 95.1 t ha-1 in Inceptisol, and was negatively correlated to soil K, Ca2+, and Mg2+ content and density in the top soil layer. SSC was highest in the micro-region VI (141.2 t ha-1, average value for all soil types) and lowest in RD (80.8 t ha-1). Considering the soil-plant ecosystem and the usual rotation age (84 months), the absolute SSC value was greatest in the micro-region SA (251.6 t ha-1) and lowest in RD (186.8 t ha-1). Regression equations showed that the clay and aluminum content and altitude and water stress explained most of the SSC variation.

Stape J.L.,North Carolina State University | Binkley D.,Colorado State University | Ryan M.G.,U.S. Department of Agriculture | Ryan M.G.,Colorado State University | And 14 more authors.
Forest Ecology and Management | Year: 2010

We examined the potential growth of clonal Eucalyptus plantations at eight locations across a 1000+ km gradient in Brazil by manipulating the supplies of nutrients and water, and altering the uniformity of tree sizes within plots. With no fertilization or irrigation, mean annual increments of stem wood were about 28% lower (16.2 Mg ha-1 yr-1, about 33 m3 ha-1 yr-1) than yields achieved with current operational rates of fertilization (22.6 Mg ha-1 yr-1, about 46 m3 ha-1 yr-1). Fertilization beyond current operational rates did not increase growth, whereas irrigation raised growth by about 30% (to 30.6 Mg ha-1 yr-1, about 62 m3 ha-1 yr-1). The potential biological productivity (current annual increment) of the plantations was about one-third greater than these values, if based only on the period after achieving full canopies. The biological potential productivity was even greater if based only on the full-canopy period during the wet season, indicating that the maximum biological productivity across the sites (with irrigation, during the wet season) would be about 42 Mg ha-1 yr-1 (83 m3 ha-1 yr-1). Stands with uniform structure (trees in plots planted in a single day) showed 13% greater growth than stands with higher heterogeneity of tree sizes (owing to a staggered planting time of up to 80 days). Higher water supply increased growth and also delayed by about 1 year the point where current annual increment and mean annual increment intersected, indicating opportunities for lengthening rotations for more productive treatments as well as the influence of year-to-year climate variations on optimal rotations periods. The growth response to treatments after canopy closure (mid-rotation) related well with full-rotation responses, offering an early opportunity for estimating whole-rotation yields. These results underscore the importance of resource supply, the efficiency of resource use, and stand uniformity in setting the bounds for productivity, and provide a baseline for evaluating the productivity achieved in operational plantations. The BEPP Project showed that water supply is the key resource determining levels of plantation productivity in Brazil. Future collaboration between scientists working on silviculture and genetics should lead to new insights on the mechanisms connecting water and growth, leading to improved matching of sites, clones, and silviculture. © 2010 Elsevier B.V.

Ryan M.G.,U.S. Department of Agriculture | Ryan M.G.,Colorado State University | Stape J.L.,North Carolina State University | Binkley D.,Colorado State University | And 13 more authors.
Forest Ecology and Management | Year: 2010

Wood production varies substantially with resource availability, and the variation in wood production can result from several mechanisms: increased photosynthesis, and changes in partitioning of photosynthesis to wood production, belowground flux, foliage production or respiration. An understanding of the mechanistic basis for patterns in wood production within a stand and across landscapes requires a complete annual carbon budget. We measured annual carbon flows to wood production, foliage production and total belowground carbon flux (the sum of root production, root respiration, and mycorrhizal production and respiration) from ages three to five years in clonal Eucalyptus plantations at four sites in Brazil to test if fertility, water availability and stand structure changed wood production and by what mechanism. We also quantified the patterns in light interception and the efficiency of light use to provide additional mechanistic insights into growth responses and to determine if light-use efficiency was related to changes in flux and partitioning. The routine level of forest fertilization at these four sites was high enough that further increases in nutrient supply did not increase wood growth. Irrigation increased wood net primary productivity (age three to five) from 1.45 to 1.84 kg m-2 year-1 of C (27%), because of increases in light interception (5%), photosynthetic efficiency (from 0.028 to 0.031 mol C/mol photons absorbed, 11%), gross primary productivity (from 3.62 to 4.28 m-2 year-1 of C, 18%), and partitioning to wood (from 0.397 to 0.430 of photosynthesis, 8%). These changes increased light-use efficiency by 20%. Annual flux belowground varied among sites from 0.43 to 1.0 m-2 year-1 of C but did not vary with water availability. Across the four sites for the irrigated and unirrigated treatments, light-use efficiency was positively correlated with gross primary productivity and partitioning to wood production. Increasing heterogeneity of stand structure (resulting from staggered timing of planting within plots) led to a 14% loss in wood biomass relative to uniform stand structure at age six. Light-use efficiency, gross primary productivity, and wood net primary productivity were lower, but not significantly so, in heterogeneous compared to uniform stands.

Binoti D.H.B.,Federal University of Vicosa | Da Binoti M.L.M.S.,Federal University of Vales do Jequitinhonha and Mucuri | Leite H.G.,Federal University of Vicosa | Silva A.,CENIBRA
Revista Brasileirade Ciencias Agrarias | Year: 2013

The cost for the inventory of even-aged forest is significant, therefore the objective of this study was to develop, build and validate a model to estimate the height of even-aged stands of eucalyptus using artificial neural networks (ANN). Data from 1870 trees measured in the Southern region of Bahia was used. ANN were trained for different percentages of measurements of heights (90, 80, 70, 60, 50, 40, 30, 20 and 10%) of the plots. The methodology allows to reduce considerably the cost to conduct a forest inventory, without significant depreciation of the estimates.

Discover hidden collaborations