Journal of Forestry Research (2009) 20(1):15–22 DOI 10.1007/s11676-009-0003-5 - Aboveground nutrient components of Eucalyptus camaldulensis and E. grandis in semiarid Brazil under the nature and the mycorrhizal inocu- lation conditions Marcela C. Pagano 1 *, Antonio F. Bellote 2 , Maria R. Scotti 1 1 Microorganism-Plant Interaction Laboratory, Institute of Biological Sciences, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, CEP: 31270-901, Belo Horizonte, MG, Brazil. 2 Embrapa Forestry, Estrada da Ribeira, km 111, Caixa Postal 319 - Colombo, PR - 83411-000- , Brazil. Abstract: A study was conducted to evaluate the aboveground biomass, nutrient content and the percentages of mycorrhizal colonization in Eucalyptus camaldulensis and Eucalyptus grandis plantations in the semiarid region (15° 09' S 43° 49' W) in the north of the State of Minas Gerais in Brazil. Results show that the total above-ground biomass (dry matter) was 33.6 Mg·ha -1 for E. camaldulensis and 53.1 Mg·ha -1 for E. grandis. The biomass of the stem wood, leaves, branches, and stem bark for E. camaldulensis accounted for 64.4%, 19.6%, 15.4%, and 0.6% of the total biomass, respectively (Table 2); meanwhile a similar partition of the total above-ground biomass was also found for E. grandis. The dry matter of leaves and branches of E. camaldulensis accounted for 35% of total biomass, and the contents of N, P, K, Ca, Mg, and S in leaves and branches accounted for 15.5%, 0.7%, 12.3%, 22.6%, 1.9%, and 1.4% of those in total above-ground biomass, respec- tively. In the trunk (bark and wood), nutrient accumulation in general was lower. Nutrient content of E. grandis presented little variation compared with that of E. camaldulensis. Wood localized in superior parts of trunk presented a higher concentration of P and bark contained significant amounts of nutrients, especially in E. grandis. This indicated that leaving vegetal waste is of importance on the site in reducing the loss of tree productivity in this semi-arid region. The two species showed mycotrophy. Keywords: Eucalyptus; biomass; nutrient components; semi-arid region; mycorrhizal symbioses; Brazil Introduction Eucalyptus, native from Australia, with more than 600 species, has been used as a monoculture in afforestation programs. In many countries these plantations are used in cellulose industries, pharmaceutics and hygiene. The Eucalyptus species present characteristics suitable for commercial use, such as fast growth, high cellulose production and resistance to environmental stress and diseases (Santos et al. 2001). In Brazil, for a sustainable production in intensive systems of wood extraction, to keep or improve the nutritional soil levels is essential. Studies showed a general upward trend in N fertilizer requirements in commercial Foundation project: This study was financed by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) Received: 2008-03-28; Accepted: 2008-10-30 © Northeast Forestry University and Springer-Verlag 2009 The online version is available at http://www.springerlink.com Biography: Marcela Claudia Pagano (1966-), *Corresponding author, female, Major: Botany; Postdoctoral researcher at Federal University of Minas Gerais, Brazil . e-mail: marpagano@gmail.com Responsible editor: Chai Ruihai eucalypt plantations (Gonçalves et al. 2004; Laclau et al. 2005; Corbeels et al. 2005) and the N inputs are a major cost in Brazilian silviculture not to mention the potential risks of pollution and leaching of nitrates in tropical forest soils (Fisher and Binkley 2000). Gonçalves (1995) reported the nutrient accumulation in 5–6 year-old Eucalyptus grandis plantations in Brazil and observed that during harvesting part of nutrients remain in the ecosystem accumulated in leaves, branches and litter when these are not removed from the site. Nevertheless, 30% of nitrogen (N), phosphorus (P) and calcium (Ca), and 43% of potassium (K) are removed when wood is extracted. The loss of N, P, K and Ca increases 40%, 60%, 65%, and 48%, respectively, when bark is extracted with wood. Mineral fertilization is a common practice to improve productivity; however, management policies need fur- ther studies. Most biomass and nutrients accumulated by planted E. grandis occurred between two and five years of age, when the leaf area is expanding. E. camaldulensis is very widely distributed in inland Australia along river banks. This fast growing tree species can tolerate moderate salinity, alkalinity, extended dry seasons and waterlogging, and is extensively planted throughout the world for purposes such as shade, shelter, agroforestry, fur- niture and industrial wood production (Midgley et al. 1989; Marques Júnior et al. 1996). The rotation length is about 3–5 years for E. camaldulensis and 7 years for E. grandis (Campinhos RESEARCH PAPER