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iForest -Biogeosciences and Forestry
IntroductionDue to growing needs for timber and wood products, forest plantations have increased around the world and have gained economical relevance. At the same time there has been an increase in concerns regarding the sustainability of planted forests, especially those managed under a regime of short rotations (Nambiar 1995). In particular, the relationship between forest nutrition and sustainable timber production has become an important issue for the management of less studied species in countries such as Costa Rica and China , Arias et al. 2011, Qiong et al. 2011.Teak (Tectona grandis L.f.) plantations have been widely established in Central America, initially in Costa Rica and Panama (De Camino et al. 2002) (Pandey & Brown 2000, De Camino et al. 2002. In this kind of short-rotation, intensively-managed forest plantations, nutrient management is a key issue for attaining sustainability and maintaining yields for future rotations (Poels 1994, Evans & Turnbull 2004. Appropriate knowledge regarding teak nutrition is required to improve plantation management and to attain high productivity and sustainability. Nutrient accumulation increases with the stand's age, mainly due to biomass accumulation; however, nutrient uptake during early years is considered crucial to sustain the high growth rates and the rapid expansion of both crown and roots required to maintain an appropriate nutritional status throughout the entire rotation length (Miller 1981, Laclau et al. 2003. In general, foliage is the tree tissue with the highest nutrient concentration and it is considered to contain 20-40% of total stand nutrients, while tree stems are assumed to have relatively low concentrations of nutrients (Miller 1984(Miller , 1995. However, the high amount of biomass accumulated in the tree stem makes it an important sink of nutrients. As a consequence, the loss of nutrients through wood removal at harvesting is a major cause of impoverishment of forest sites (Fölster & Khanna 1997, Worrel & Hampson 1997. While N, P and Mg are mainly accumulated in the tree stem, bark and roots are considered to be Ca sinks (Nwoboshi 1984). Nutrient uptake depends mainly on the species' demand and its ability to access nutrients, as well as the potential of the site (especially the soil) to supply nutrients. In calcareous soils in India, the most absorbed nutrients by teak were Ca > K > N > Mg > P = S (Negi et al. 1995), while they were K > N > Ca >> Mg ≥ P in less fertile soils in Africa (Nwoboshi 1984) and N > Ca > K > Mg > P > Na > S > Cl in a different study site in India ).In order to understand the relationship between soil and forest nutrition, it has been long recognized that it is first necessary to evaluate the quantities of nutrients taken up by the growing forest and removed from the site during timber extraction (Rennie 1955). However, Fölster & Khanna (1997) pointed out a traditional and general lack of concern of this problem in planted forests. Soil-plant relation research in agricultu...
