Acessibilidade / Reportar erro

EFFECT OF PLANTING AGE AND SPACING ON ENERGY PROPERTIES OF Eucalyptus grandis W. Hill EX Maiden

EFEITO DA IDADE E DO ESPAÇAMENTO DE PLANTIO NAS PROPRIEDADES ENERGÉTICAS DO Eucalyptus grandis W. Hill ex Maiden

ABSTRACT

This study aimed to determine the effect of planting age and spacing on energy properties of different compartments of the biomass of Eucalyptus grandis W. Hill ex Maiden, disseminated in different spacings: 2.0 x 1.0 m, 2.0 x 1.5 m, 3.0 x 1.0 m e 3.0 x 1.5 m, in the 1st, 3rd and 5th year after the planting. The present study was carried out as an experiment installed in an experimental design of randomized complete blocks in three replications. Variables determined were Biomass (BIO), Gross Calorific Value (GCV), Basic Density (BD), Energy Productivity (EP), Energy Density (ED), Fixed Carbon Content (FCC), Volatile Material Content (VMC), and Ash Content (AC). Ages have an effect on all studied variables, and in the 5th year after planting, the largest BIO, EP, BD, ED and FCC values are checked. The planting spacings induce different productions of BIO and EP, with a trend towards lower values with increasing planting spacing in all assessed periods. The compartments of trees influence BIO, GCV, FCC, VMC and AC variables. Regarding to energy, the higher the age and lower the planting spacing, the better the energy properties of biomass.

Keywords:
Biomass; Gross Calorific Value; Energy Productivity

RESUMO

Esse trabalho teve como objetivo determinar o efeito da idade e do espaçamento de plantio nas propriedades energéticas de diferentes compartimentos da biomassa de Eucalyptus grandis W. Hill ex Maiden, distribuída em diferentes espaçamentos: 2,0x1,0 m, 2,0x1,5 m, 3,0x1,0 m e 3,0x1,5 m, no 1º, 3º e 5º ano após o plantio. O presente trabalho foi realizado em um experimento instalado em delineamento experimental de blocos completos casualizados em três repetições. Foram determinadas as variáveis biomassa (BIO), poder calorífico superior (PCS), massa específica básica (ME), produtividade energética (PE), densidade energética (DE), teor de carbono fixo (CF), teor de material volátil (MV) e teor de cinzas (CZ). As idades proporcionam um efeito em todas as variáveis analisadas, sendo que no 5º ano após o plantio, são verificados os maiores valores de BIO, PE, ME, DE e CF. Os espaçamentos de plantio induzem a diferentes produções de BIO e PE, com uma tendência de redução dos valores com o aumento do espaçamento de plantio, em todos os períodos avaliados. Os compartimentos das árvores influenciam nas variáveis BIO, PCS, PE, CF, MV e CZ. Do ponto de vista energético, quanto maior a idade e menor o espaçamento de plantio, melhores são as propriedades energéticas da biomassa.

Palavras-chave:
Biomassa; Poder calorífico superior; Produtividade energética

1. INTRODUCTION

The development of mankind is closely associated with an increase in energy consumption and the rational use of various sources of energy. Over the past decades, that energy demand has been mainly based on non-renewable sources, setting off a series of questions regarding energy supply and environmental and economic balance. So, many countries have been looking for alternatives to minimize these problems, particularly by intensifying the use of renewable sources, including forest biomass.

With the growing demand for renewable energy sources, studies regarding the potential of generation originating from forest biomass have been conducted in Brazil and in the world, reporting the potential of biomass for a clean energy production, such as those developed by Lemenih and Bekele (2004)LEMENIH, M.; BEKELE, T. Effect of age on calorific value and some mechanical properties of three Eucalyptus species grown in Ethiopia. Biomass e Bioenergy, v.27, p.223-232, 2004.; Lima et al. (2011);LIMA, E.A.; SILVA, H.D.; LAVORANTI, O.J. Caracterização dendroenergética de árvores de Eucalyptus benthamii. Pesquisa Florestal Brasileira, v.31, n.65, p.9-17, 2011. Vidaurre et al. (2012)VIDAURRE, G.B.; CARNEIRO, A.C.O.; VITAL, B.R.; SANTOS, R.C.; VALLE, M.L.A. Propriedades energéticas da madeira e do carvão de paricá (Schizolobium amazonicum). Revista Árvore, v.36, n.2, p.365-371, 2012.; Protásio et al. (2013)PROTÁSIO, T.P.; COUTO, A.M.; REIS, A.A.; TRUGILHO, P.F. Seleção de clones de Eucalyptus para a produção de carvão vegetal e bioenergia por meio de técnicas univariadas e multivariadas. Sientia Forestalis, v.41, n.97, 2013.; Caron et al. (2015)CARON, B.O.; ELOY, E.; SOUZA, V.Q.; SCHMIDT, D.; BALBINOT, R.; BEHLING, A.; MONTEIRO, G.C. Quantificação da Biomassa florestal em plantios de curta rotação com diferentes espaçamentos. Comunicata Scientiae, v.6, n.1, p.106-112, 2015.; Eloy et al. (2015)ELOY, E.; CARON, B.O.; SILVA, D.A.; SOUZA, V.Q.; TREVISAN, R.; BEHLING, A.; ELLI, E.F. Produtividade energética de espécies florestais em plantios de curta rotação. Ciência Rural, v.45, n.8, p.1424-1431, 2015.. However, to increase the efficiency of the conversion of wood into energy, the adoption of the most appropriate technologies is needed to assess its true potential in the carbonization, heat making, and power cogeneration (SILVA et al., 2012SILVA, D.A.; CARON, B.O.; BEHLING, A.; SOUZA, V.Q.; ELOY, E. Ponto de amostragem ao longo do fuste para estimativa do poder calorífico da madeira. Ciência Rural, v.42, n.9, p.1588-1595, 2012.); thus, turning expectations regarding the use of forest biomass as a feedstock for power generation auspicious.

In Brazil, in 1940, approximately 80% of energy consumption came from wood. In 1970 this percentage was reduced to 45%, in 2013 to 8.3% (EPE, 2014EMPRESA DE PESQUISA ENERGÉTICA - EPE. Balanço Energético Nacional 2014: ano base 2013. Rio de Janeiro: 2014. 288p.). Despite this decrease in participation of wood as an energy source, in quantitative terms, the consumption has not changed significantly, evidencing that there is a captive market for the use of forest biomass as an energy source.

The selection of species, both native and exotic, is extremely important for its use as an alternative energy source. Nonetheless, for this to be viable, knowledge regarding the essential characteristics is necessary for that use, in relation to ecological and silvicultural factors and those ones related to energy potential, supporting, thus, the decision-making for implementation of forest plantations (MOREIRA, 2011MOREIRA, J.M.M.A.P. Potencial de participação das florestas na matriz energética. Pesquisa Florestal Brasileira, v.31, n.68, p.363-372, 2011.).

The use of wood for energy purposes is elevated in Brazil, mainly motivated by the diversity of species with energetic properties. Thus, the presence of established forest experiments with known original conditions of location, planting and ages of trees is essential, for new information regarding the qualification of species for energy generation to be allowed and, by extension, with propensity to formation of forest regions for fuelwood material production.

One of the main factors that affects the formation of forests is the spacing practiced in plantings, because it has silvicultural, technological and economic implications, interfering with growth rates of plants, cutoff age, quality of wood, forestry practices employed and, therefore, production costs (ELOY, 2013ELOY, E.; CARON, B.O.; TREVISAN, R.; SCHMIDT, D.; ZANON, M.L.B.; BEHLING, A.; MONTEIRO, G.C. Variação longitudinal e efeito do espaçamento na massa específica básica da madeira de Mimosa scabrella e Ateleia glazioveana Floresta, v.43, n.2, p.327-334, 2013.). Thus, when it aims to timber production for energy purposes, normally recommended to be narrower spacing plant in order to produce a greater volume of biomass per unit area in less time possible.

In this context, this study aimed to determine the effect of planting age and spacing on energy properties of different compartments of the biomass of Eucalyptus grandis W. Hill ex Maiden.

2. MATERIALS AND METHODS

2.1 Characterization of the study area

The work was carried out in the experiment located in an area pertaining to the Federal University of Santa Maria (UFSM) under geographic coordinates 27º22'S; 53º 25'W, 480 m altitude, in the city of Frederico Westphalen, Rio Grande do Sul.

According to the Köppen climate classification, the climate in this region is Cfa, i.e. Humid subtropical climate, with an average annual temperature of 19.1º C, varying with maximum of 38 º C and minimum of 0 º C, with an average annual rainfall of 1606 mm. The experimental area is far from Iraí, the city taken as a reference for the data of climate classification, from approximately 30 km. As proposed by Maluf (2000)MALUF, J.R.T. Nova classificação climática do Estado do Rio Grande do Sul. Revista Brasileira de Agrometeorologia, v.8, n.1, p.141-150, 2000., Iraí has an average annual temperature of 18.8 º C and an average temperature, in the coldest month, of 13.3 ºC.

The experiment was conducted using a design of experimental randomized complete blocks. They were characterized by a 3x4x4 factorial, i.e. three periods (1st, 3rd and 5th years after planting), four planting spacings (2.0x1.0 m; 2.0 x 1.5 m; 3.0 x 1.0 and 3.0 x 1.5 m) and four compartments of trees (wood, bark, branch and leaf) in three replications. The block includes 16 experimental units, each of which has 45 plants located in five planting rows.

The soil of the area is classified as typical dystrophic Red Latosol, clayey texture, deep and well-drained corresponding to Passo Fundo mapping unit (EMBRAPA, 2006EMPRESA BRASILEIRA DE PESQUISA AGROPECUÁRIA - EMBRAPA. Sistema brasileiro de classificação de solos. 2ª.ed. Rio de Janeiro: 2006. 412p.).

2.2 Sampling

The destructive assessments of the trees were carried out in three different periods: in 1st year (2009), 3rd year (2011) and 5th year (2013), after planting the experiment, when 36 trees were assessed per period. From those, six discs were removed with approximately two centimeters thick, in the following positions along the stem: 0% (basis), 1.30 m (diameter at breast height - DBH), 25%, 50%, 75% and 100% of the total height of the tree, and also two symmetrically opposed wedges of each disk were selected.

Samples of branches and leaves were collected from the plant in a stratified manner, i.e. the lower, middle and upper layer of the canopy of the trees, in order to obtain a homogeneous material that represents the entire length of the canopy. These were identified and taken to a drying and air circulation and renewal oven, in order to obtain the dry product. The samples of wood, bark, leaf and brunch were dried at 103 ºC at 0% moisture, to determine the respective humidity content.

2.3 Characterization of the assessments performed

To determine the biomass (BIO), the direct method was used, which consisted on cutting and weighing the different compartments of the trees (SANQUETTA, 2002SANQUETTA, C.R. Métodos de determinação de biomassa florestal. In: SANQUETTA, C.R. (Ed.). As florestas e o carbono. Curitiba: 2002. p.119-140.). The total fresh masses of sampled trees were determined under field conditions, and samples were taken from each compartment to obtain the moisture content in the laboratory.

For determining the gross calorific value (GCV) and the Immediate Chemical Analysis (ICA), materials obtained in sampling were used, that were grounded into a slicer with a 40-mesh sieve, in order to obtain a thinner and more uniform material. Evaluations of the GCV were performed using a digital bomb calorimeter, C5000 Cooling System model, IKA Werke, with adiabatic operating principle, according to the technical standard NBR 8633 (ABNT, 1984ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS - NBR 8633: carvão vegetal: Determinação do poder calorífico superior. Rio de Janeiro: 1984. 13p.), and, in the case of the ICA, was used the technical standard 8112 NBR (ABNT, 1986ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS - NBR 8112: carvão vegetal: análise imediata. Rio de Janeiro: 1986. 6p.), from which were obtained the concentrations of volatile, ashes and fixed carbon materials.

To determine the Basic Density (BD), the materials obtained in the sampling were used. The procedures were performed according to the technical standard NBR 11941 (ABNT, 2003ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS - ABNT. NBR 11941: Determinação da densidade básica da madeira. Rio de Janeiro: 2003. 6p.).

For determining the Energy Productivity (EP), the BIO values with their respective GCV were multiplied according to the following expression:

(1)

Where: EP = Energy Productivity (Gcal ha-1); BIO = Dry Biomass of each compartment (ton ha-1) and GCV = Gross Calorific Value (kcal kg-1).

To determine the Energy Density (ED), BD and GCV values were multiplied according to the following expression:

(2)

Where: ED = Energy Density (kcal m-3); BD = wood Basic Density according to the volume of the tree (kg m-3) and GCV= Gross Calorific Value (kcal kg-1).

2.4 Data Analysis

The obtained data was subjected to statistical analysis, which proceeded with the test assumption of homogeneity of variances, analysis of variance, regression analysis, F-test and Tukey's range test at 5% probability of error.

3. RESULTS

Analysis of variance revealed differences among the three studied periods and among the four compartments of the trees, for all analyzed variables. Likewise, this characteristic was observed among the four planting spacings for variables BIO and EP.

In the 1st year of assessment, BIO and EP did not differ among the different compartments of the trees. In GCV and FCC cases, a difference was observed: the leaf showed the highest average values. Similarly, the same variation was observed in AC and VMC for bark and wood compartments, respectively. In BD and wood ED cases, the highest values were 0.391 g cm-3 and 1.770 Gcal m-3, respectively (Table 1).

Table 1
Average test for energy variables of the compartments of Eucalyptus grandis, distributed in different spacings, one year after planting in the city of Frederico Westphalen-RS.
Tabela 1
Teste de médias para as variáveis energéticas dos compartimentos das árvores de Eucalyptus grandis, distribuídas em diferentes espaçamentos, um ano após o plantio, no município de Frederico Westphalen-RS.

In the 3rd year of assessment, the highest BIO values were observed in the wood compartment in smaller planting spacings. Also, this characteristic was observed for EP in the same compartment. The highest average values of GCV were reported for the leaf. Nevertheless, peel presented the lowest GCV values for all the spacings (Table 2).

Table 2
Average test for energy variables of the compartments of Eucalyptus grandis, distributed in different spacings, three years after planting in the city of Frederico Westphalen-RS.
Tabela 2
Teste de médias para as variáveis energéticas dos compartimentos das árvores de Eucalyptus grandis, distribuídas em diferentes espaçamentos, três anos após o plantio, no município de Frederico Westphalen-RS..

As observed in the 3rd year of assessment, at 5th year the production of BIO and EP of the wood was different and statistically superior to other compartments of the trees. Just as in the two previous periods, in the 5th year of assessment the highest average values were observed in the leaf, detecting maximum values of 5,055 kcal kg-1 (Table 3).

Table 3
Average test for energy variables of the compartments of Eucalyptus grandis, distributed in different spacings, five years after planting in the city of Frederico Westphalen-Rio Grande do Sul.
Tabela 3
Teste de médias para as variáveis energéticas dos compartimentos das árvores de Eucalyptus grandis, distribuídas em diferentes espaçamentos, cinco anos após o plantio, no município de Frederico Westphalen-RS.

For FCC, in general, it was reported the highest average values for the bark, and the lowest ones for the branch compartment, which was different and inferior inside spacings for most of the other compartments. Nevertheless, the highest average values for VMC were reported for wood, being statistically higher than bark and leaf in all spacings (Table 3).

From the BIO analysis of the different compartments of trees in relation to the four planting spacings, a direct relationship with the planting density in the three ages was observed. That is, in treatments with higher densities were observed higher BIO values, when compared with lower density spacings, and decreasing trends of this variable in the different compartments of the plant can be observed, due to the increase of usable area.

In Figure 1, regression equations of the different compartments over the three periods are presented, for all assessed variables. In general, a growing trend of compartments was observed, especially in wood, for BIO and EP variables, in relation to the different years evaluated, with no tendency to stabilization since the evaluation period influenced compartments of the trees production.

Figure 1
Regression equations for biomass (A), energy productivity (EP) (B), Gross Calorific Value (GCV)(C), Fixed Carbon Content (FCC)(D), Volatile Material Content (VMC)(E), Ash Content (AC)(F), Basic Density (BD)(G) and Energy Density (ED)(H) in the 1st, 3rd and 5th year after planting in the city of Frederico Westphalen-RS.
Figura 1
Equações de regressão para a biomassa (A), produtividade energética (EP)(B), poder calorífico superior (GVC)(C), teor de carbono fixo (FCC) (D), teor de materiais voláteis (VMC)(E), teor de cinzas (AC)(F), massa específica básica (BD)(G) e densidade energética (ED)(H), no 1º, 3º e 5º ano após o plantio, no município de Frederico Westphalen-RS.

Although significant models for ED and EP along the three periods (Figure 1) were identified, it was observed that there is not a systematic variation in increase or decrease for these variables over time, consequently, a clear trend wasn't detected. Therefore, it is emphasized the importance of those variables that consider the energy contained in a determined volume and weight of wood, respectively.

4. DISCUSSION

According to Oliveira Neto et al. (2003)OILIVEIRA NETO, S.N.; REIS, G.G.; REIS, M.G.F.; NEVES, J.C.L. Produção e distribuição de biomassa em Eucalyptus camaldulensis Dehn. em resposta à adubação e ao espaçamento. Revista Árvore, v.27, n.1, p.15-23, 2003., there is a bigger production of BIO per unit of area in the minor spacings, mainly due to the larger number of individuals. This justifies the decreasing trends in BIO production in the different compartments of the plants, due to the increase of planting spacing. Though, Müller et al. (2005)MÜLLER, M.D.; COUTO, L.; LEITE, H.G.; BRITO, J.O. Avaliação de um clone de eucalipto estabelecido em diferentes densidades de plantio para produção de biomassa e energia. Biomassa & Energia, v.2, n.3, p.177-186, 2005. emphasize that, over time, the amount of stored wood on a particular location tends to level off at different spacings, even though in the higher densities occurs stagnation of growth at earlier ages and in the plantations with broader spacings it appears at advanced ages.

The values observed in this study were lower than those found in the literature with populations of different ages. Lima et al. (2011)LIMA, E.A.; SILVA, H.D.; LAVORANTI, O.J. Caracterização dendroenergética de árvores de Eucalyptus benthamii. Pesquisa Florestal Brasileira, v.31, n.65, p.9-17, 2011. reported an average productivity of biomass of the E. benthamii bole, 416 ton ha-1ton ha-1 at 6 years old. Brito et al. (1983)BRITO, J.O.; BARRICHELO, L.E.G.; SEIXAS, F.; MIGLIORINI, A.J.; MURAMOTO, M.C. Análise da produção energética e de carvão vegetal de espécies de eucalipto. IPEF, n.23, p.53-56, 1983. reported values for E. saligna, 405.6 ton ha-1 and E. grandis (518.2 ton ha-1) at 10 years old. This data is verified by authors who have developed several works related to the influence of planting spacing and age of the population in the production of forest populations, presenting a difference in the distribution of BIO among the species and in the same species (MÜLLER et al., 2005MÜLLER, M.D.; COUTO, L.; LEITE, H.G.; BRITO, J.O. Avaliação de um clone de eucalipto estabelecido em diferentes densidades de plantio para produção de biomassa e energia. Biomassa & Energia, v.2, n.3, p.177-186, 2005.).

The average values for E. grandis GCV are in accordance with those reported in the literature. In studies based on Hofler et al. (2010)HOFLER, J.; BIANCHI, M.L.; SOARES, V.C. Variação da composição química e poder calorífico da madeira de clones de Eucalyptus de diferentes idades. 33ª Reunião anual da sociedade brasileira de química, 2010, Águas de Lindóia-SP., average values were observed in 3, 5 and 7 year-old Eucalyptus clones respectively, equivalent to 3,348, 4,529 and 4,378 kcal kg-1. Likewise, Quirino et al. (2005)QUIRINO, W.F.; VALE, A.T.; ANDRADE, A.P.A.; ABREU, V.L.S.; AZEVEDO, A.C.S. Poder calorífico da madeira e de materiais ligno-celulósicos. Revista da Madeira, v.15, n.89, p.100-106, 2005. conducted a literature review related to GCV of wood from 258 exotic and native tropical forest species, and reported that the average values were 4,710 kcal kg-1, ranging from 3,831 to 5,324 kcal kg-1.

Santana (2009)SANTANA, W.M.S. Crescimento, produção e propriedades da madeira de um clone de Eucalyptus grandis e E. urophylla com enfoque energético. 2009. 91f. Dissertação (Mestrado em Tecnologia da Madeira) - Universidade Federal de Lavras, Lavras, 2009. verified that the GCV is little influenced by age, so a conclusive trend can't be confirmed. The same author mentions that factors related to the structural composition of wood positively influence its energy potential, especially those with regard to chemical and elemental constitution. In contrast, Lemenih and Bekele (2004)LEMENIH, M.; BEKELE, T. Effect of age on calorific value and some mechanical properties of three Eucalyptus species grown in Ethiopia. Biomass e Bioenergy, v.27, p.223-232, 2004., by evaluating the effect of age on the GCV of wood in Eucalyptus species, mention a negative relationship with the age of the tree, presenting a small difference between the ages of 11-21. Similar results were reported by Vidaurre et al. (2012)VIDAURRE, G.B.; CARNEIRO, A.C.O.; VITAL, B.R.; SANTOS, R.C.; VALLE, M.L.A. Propriedades energéticas da madeira e do carvão de paricá (Schizolobium amazonicum). Revista Árvore, v.36, n.2, p.365-371, 2012. with Schizolobium amazonicum, reporting that the youngest age had the highest GCV values, with a downward trend with the increasing age of the tree.

VMC and FCC levels in wood are according to Brito and Barrichello (1982)BRITO, J.O.; BARRICHELO, L.E.G Aspectos técnicos da utilização da madeira e carvão vegetal como combustíveis. In: SEMINÁRIO DE ABASTECIMENTO ENERGÉTICO INDUSTRIAL COM RECURSOS FLORESTAIS, 2., 1982, São Paulo. São Paulo: 1982. p.101-137., who delimit, in general, the VMC content ranging from 75% to 85%, and the FCC from 15% to 25%. According to these authors, combustibles with high FCC rates are desirable, as they perform a slower burning, resulting in a longer residence time inside the machines. According Vieira et al. (2013)VIEIRA, A.C.; SOUZA, S.N.M.; BARICCATTI, R.A.; SIQUEIRA, J.A.C.; NOGUEIRA, C.E.C. Caracterização da casca de arroz para geração de energia. Revista Varia Scientia Agrárias, v. 3, n. 1, p. 51-57, 2013., the VMC content positively interferes in the ignition facilitating it, although the combustion process is fast. For these authors, the AC content is undesirable for an energy product, reducing the GCV and causing loss of efficiency of the product, because it corresponds to substances that do not burn when in solid form. Botrel et al. (2010)BOTREL, M.C.G.; TRUGILHO, P.F.; ROSADO, S.C.S.; MOREIRA DE SILVA, J.R. Seleção de clones de Eucalyptus para biomassa florestal e qualidade da madeira. Scientia Forestalis, v.38, n.86, p.237-245, 2010., working with eight Eucalyptus clones, found AC values ranging from 0.11 to 0.25%.

In relation to BD, the results observed in this study are within the range that Quirino et al. (2005)QUIRINO, W.F.; VALE, A.T.; ANDRADE, A.P.A.; ABREU, V.L.S.; AZEVEDO, A.C.S. Poder calorífico da madeira e de materiais ligno-celulósicos. Revista da Madeira, v.15, n.89, p.100-106, 2005. reported for 108 forest species, ranging from 0.200 to 1.080 g cm-3. They also corroborate the results observed by Eloy et al. (2014)ELOY, E.; CARON, B.O.; SILVA, D.A.; SCHMIDT, D.; TREVISAN, R.; BEHLING, A.; ELLI, E.F. Influência do espaçamento nas características energéticas de espécies arbóreas em plantios de curta rotação. Revista Árvore, v.38, n.3, p.551-559, 2014., who found no effect of spacing in the BD of the wood. However, they are different from those found by Pauleski (2010)PAULESKI, D.T. Influência do espaçamento sobre o crescimento e a qualidade da madeira de Pinus taeda L.. 2010. 198f. Tese (Doutorado em Engenharia Florestal) - Universidade Federal de Santa Maria, Santa Maria, 2010., which reported an increase on BD with the increase of planting spacing. In contrast, Garcia et al. (1991)GARCIA, C.H.; CORRADINE, L.; ALVARENGA, S.F. Comportamento florestal do Eucalyptus grandis e Eucalyptus saligna em diferentes espaçamentos. IPEF Circular Técnica, n.179, p.1-8, 1991. reported a decrease of the BD of the wood with the increase of spacing in wood from E. grandis and E. saligna. For Eloy et al. (2013)ELOY, E. Quantificação e caracterização da biomassa florestal em plantios de curta rotação. 2013. 88f. Dissertação (Mestrado em Agronomia) - Universidade Federal de Santa Maria, Frederico Westphalen, 2013. those differences in the results could be due to several factors, such as genetic variability of the populations and different environmental conditions, based on the different ages.

The difference in BD observed in those periods is supported by several authors who have studied this technological characteristic. Trevisan et al. (2012)TREVISAN, R.; ELOY, E.; DENARDI, L.; HASELEIN, C.R.; CARON, B.O. Variação axial e efeito do desbaste na massa específica das árvores centrais de Eucalyptus grandis. Ciência Rural, v.42, n.2, p.312-318, 2012., by studying the influence of thinning in central trees of E. grandis aged 4-18, found a variation in the average BD values of 0.390 to 0.462 g cm-3, confirming the existence of variability within species and among the different ages of the populations.

The ED that considers the energy contained in a specific volume of wood was more influenced by the SG than the GCV that varied less. For Moreira et al. (2012)MOREIRA, J.M.M.A.P.; LIMA, E.A.; GOULART, I.C.G.R. Impacto do teor de umidade e da espécie florestal no custo da energia útil obtida a partir da queima da lenha. Colombo: 2012. 5p. (Comunicado Técnico Embrapa, 293), the BD and the GCV vary among the species, among individuals from the same species according to their age, justifying the reported variation in this work. Neves et al. (2013)NEVES, T.A.; PROTÁSIO, T.P.; TRUGILHO, P.F.; VALLE, M.L.A.; SOUSA, L.C.; VIEIRA, C.M.M. Qualidade da madeira de clones de Eucalyptus em diferentes idades para a produção de bioenergia. Revista Ciências Agrárias, v.56, n.2, p.139-148, 2013. reported that for Eucalyptus clones, at 4.5 and 5.6 years, the values of this variable are 2.051 and 2.084 Gcal m-3, respectively.

Similar results of EP were obtained by Santana (2009)SANTANA, W.M.S. Crescimento, produção e propriedades da madeira de um clone de Eucalyptus grandis e E. urophylla com enfoque energético. 2009. 91f. Dissertação (Mestrado em Tecnologia da Madeira) - Universidade Federal de Lavras, Lavras, 2009., by studying E. grandis and E. urophylla, reported differences among ages and spacings, and the highest values were identified in advanced ages and more dense spacings.

5. CONCLUSION

Age and planting spacing influence in the biomass energy properties of the different compartments of Eucalyptus grandis.

The three ages induce a significant effect for all analyzed variables, so in the 5th year after planting are verified the higher biomass levels, energy productivity, basic density, energy density and fixed carbon content.

Through the different ages, biomass and energy productivity of wood are superior than other compartments of the trees, so the biggest contributions to biomass follow the order wood> branch> leaf> bark.

The four planting spacings provide different biomass productions and energy productivity by reducing their values with the increase of spacing, in all assessed periods.

From the energy point of view, the higher the age and lower the planting spacing, the better the biomass energy properties.

6. REFERÊNCIAS

  • ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS - ABNT. NBR 11941: Determinação da densidade básica da madeira Rio de Janeiro: 2003. 6p.
  • ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS - NBR 8112: carvão vegetal: análise imediata Rio de Janeiro: 1986. 6p.
  • ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS - NBR 8633: carvão vegetal: Determinação do poder calorífico superior Rio de Janeiro: 1984. 13p.
  • BOTREL, M.C.G.; TRUGILHO, P.F.; ROSADO, S.C.S.; MOREIRA DE SILVA, J.R. Seleção de clones de Eucalyptus para biomassa florestal e qualidade da madeira. Scientia Forestalis, v.38, n.86, p.237-245, 2010.
  • EMPRESA DE PESQUISA ENERGÉTICA - EPE. Balanço Energético Nacional 2014: ano base 2013. Rio de Janeiro: 2014. 288p.
  • BRITO, J.O.; BARRICHELO, L.E.G.; SEIXAS, F.; MIGLIORINI, A.J.; MURAMOTO, M.C. Análise da produção energética e de carvão vegetal de espécies de eucalipto. IPEF, n.23, p.53-56, 1983.
  • BRITO, J.O.; BARRICHELO, L.E.G Aspectos técnicos da utilização da madeira e carvão vegetal como combustíveis In: SEMINÁRIO DE ABASTECIMENTO ENERGÉTICO INDUSTRIAL COM RECURSOS FLORESTAIS, 2., 1982, São Paulo. São Paulo: 1982. p.101-137.
  • CARON, B.O.; ELOY, E.; SOUZA, V.Q.; SCHMIDT, D.; BALBINOT, R.; BEHLING, A.; MONTEIRO, G.C. Quantificação da Biomassa florestal em plantios de curta rotação com diferentes espaçamentos. Comunicata Scientiae, v.6, n.1, p.106-112, 2015.
  • ELOY, E. Quantificação e caracterização da biomassa florestal em plantios de curta rotação 2013. 88f. Dissertação (Mestrado em Agronomia) - Universidade Federal de Santa Maria, Frederico Westphalen, 2013.
  • ELOY, E.; CARON, B.O.; TREVISAN, R.; SCHMIDT, D.; ZANON, M.L.B.; BEHLING, A.; MONTEIRO, G.C. Variação longitudinal e efeito do espaçamento na massa específica básica da madeira de Mimosa scabrella e Ateleia glazioveana Floresta, v.43, n.2, p.327-334, 2013.
  • ELOY, E.; CARON, B.O.; SILVA, D.A.; SCHMIDT, D.; TREVISAN, R.; BEHLING, A.; ELLI, E.F. Influência do espaçamento nas características energéticas de espécies arbóreas em plantios de curta rotação. Revista Árvore, v.38, n.3, p.551-559, 2014.
  • ELOY, E.; CARON, B.O.; SILVA, D.A.; SOUZA, V.Q.; TREVISAN, R.; BEHLING, A.; ELLI, E.F. Produtividade energética de espécies florestais em plantios de curta rotação. Ciência Rural, v.45, n.8, p.1424-1431, 2015.
  • EMPRESA BRASILEIRA DE PESQUISA AGROPECUÁRIA - EMBRAPA. Sistema brasileiro de classificação de solos 2ª.ed. Rio de Janeiro: 2006. 412p.
  • GARCIA, C.H.; CORRADINE, L.; ALVARENGA, S.F. Comportamento florestal do Eucalyptus grandis e Eucalyptus saligna em diferentes espaçamentos. IPEF Circular Técnica, n.179, p.1-8, 1991.
  • HOFLER, J.; BIANCHI, M.L.; SOARES, V.C. Variação da composição química e poder calorífico da madeira de clones de Eucalyptus de diferentes idades. 33ª Reunião anual da sociedade brasileira de química, 2010, Águas de Lindóia-SP.
  • LEMENIH, M.; BEKELE, T. Effect of age on calorific value and some mechanical properties of three Eucalyptus species grown in Ethiopia. Biomass e Bioenergy, v.27, p.223-232, 2004.
  • LIMA, E.A.; SILVA, H.D.; LAVORANTI, O.J. Caracterização dendroenergética de árvores de Eucalyptus benthamii Pesquisa Florestal Brasileira, v.31, n.65, p.9-17, 2011.
  • MALUF, J.R.T. Nova classificação climática do Estado do Rio Grande do Sul. Revista Brasileira de Agrometeorologia, v.8, n.1, p.141-150, 2000.
  • MOREIRA, J.M.M.A.P.; LIMA, E.A.; GOULART, I.C.G.R. Impacto do teor de umidade e da espécie florestal no custo da energia útil obtida a partir da queima da lenha Colombo: 2012. 5p. (Comunicado Técnico Embrapa, 293)
  • MOREIRA, J.M.M.A.P. Potencial de participação das florestas na matriz energética. Pesquisa Florestal Brasileira, v.31, n.68, p.363-372, 2011.
  • MÜLLER, M.D.; COUTO, L.; LEITE, H.G.; BRITO, J.O. Avaliação de um clone de eucalipto estabelecido em diferentes densidades de plantio para produção de biomassa e energia. Biomassa & Energia, v.2, n.3, p.177-186, 2005.
  • NEVES, T.A.; PROTÁSIO, T.P.; TRUGILHO, P.F.; VALLE, M.L.A.; SOUSA, L.C.; VIEIRA, C.M.M. Qualidade da madeira de clones de Eucalyptus em diferentes idades para a produção de bioenergia. Revista Ciências Agrárias, v.56, n.2, p.139-148, 2013.
  • OILIVEIRA NETO, S.N.; REIS, G.G.; REIS, M.G.F.; NEVES, J.C.L. Produção e distribuição de biomassa em Eucalyptus camaldulensis Dehn. em resposta à adubação e ao espaçamento. Revista Árvore, v.27, n.1, p.15-23, 2003.
  • PAULESKI, D.T. Influência do espaçamento sobre o crescimento e a qualidade da madeira de Pinus taeda L.. 2010. 198f. Tese (Doutorado em Engenharia Florestal) - Universidade Federal de Santa Maria, Santa Maria, 2010.
  • PROTÁSIO, T.P.; COUTO, A.M.; REIS, A.A.; TRUGILHO, P.F. Seleção de clones de Eucalyptus para a produção de carvão vegetal e bioenergia por meio de técnicas univariadas e multivariadas. Sientia Forestalis, v.41, n.97, 2013.
  • QUIRINO, W.F.; VALE, A.T.; ANDRADE, A.P.A.; ABREU, V.L.S.; AZEVEDO, A.C.S. Poder calorífico da madeira e de materiais ligno-celulósicos. Revista da Madeira, v.15, n.89, p.100-106, 2005.
  • SANQUETTA, C.R. Métodos de determinação de biomassa florestal. In: SANQUETTA, C.R. (Ed.). As florestas e o carbono Curitiba: 2002. p.119-140.
  • SANTANA, W.M.S. Crescimento, produção e propriedades da madeira de um clone de Eucalyptus grandis e E. urophylla com enfoque energético 2009. 91f. Dissertação (Mestrado em Tecnologia da Madeira) - Universidade Federal de Lavras, Lavras, 2009.
  • SILVA, D.A.; CARON, B.O.; BEHLING, A.; SOUZA, V.Q.; ELOY, E. Ponto de amostragem ao longo do fuste para estimativa do poder calorífico da madeira. Ciência Rural, v.42, n.9, p.1588-1595, 2012.
  • TREVISAN, R.; ELOY, E.; DENARDI, L.; HASELEIN, C.R.; CARON, B.O. Variação axial e efeito do desbaste na massa específica das árvores centrais de Eucalyptus grandis Ciência Rural, v.42, n.2, p.312-318, 2012.
  • VIDAURRE, G.B.; CARNEIRO, A.C.O.; VITAL, B.R.; SANTOS, R.C.; VALLE, M.L.A. Propriedades energéticas da madeira e do carvão de paricá (Schizolobium amazonicum). Revista Árvore, v.36, n.2, p.365-371, 2012.
  • VIEIRA, A.C.; SOUZA, S.N.M.; BARICCATTI, R.A.; SIQUEIRA, J.A.C.; NOGUEIRA, C.E.C. Caracterização da casca de arroz para geração de energia. Revista Varia Scientia Agrárias, v. 3, n. 1, p. 51-57, 2013.

Publication Dates

  • Publication in this collection
    Jul-Aug 2016

History

  • Received
    30 June 2015
  • Accepted
    02 June 2016
Sociedade de Investigações Florestais Universidade Federal de Viçosa, Departamento de Engenharia Florestal, Avenida Purdue, s/nº - Campus Universitário UFV, CEP: 36570-900, Tel.: (+55 31) 3612-3959 - Viçosa - MG - Brazil
E-mail: rarvore@sif.org.br