Nutrient accumulation and export in teak (Tectona grandis l.f.) plantations of Central America

Abstract

© 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...

Modifying harvesting time as a tool to reduce nutrient export by timber extraction: a case study in planted teak (Tectona grandis L.f.) forests in Costa Rica

“…3, Fig. S3 in Supplementary material), confirming the hypothesis stated in the introduction section (Fernández-Moya et al 2014). Thus, harvesting time influences the amount of nutrients extracted through wood removal.…”

“…Nutrient export through timber harvesting has been reported to be of specific importance for N, P and K in the various teak plantations studied in Central America (Fernández-Moya et al 2014). N and Ca are the nutrients with highest nutrient export values (220 kg N ha -1 , 281 kg Ca ha -1 ), although in the case of Ca there is no sustainability issue due to its large soil reservoir (Fernández-Moya et al 2014).…”

“…A number of studies have addressed the question of soil fertility and nutrition in planted teak forests (for an overview, see Kumar 2011 andAlvarado 2012). For example, nutrient accumulation in aerial biomass of teak has been analyzed by several authors (Nwoboshi 1984, Kumar et al 2009, Fernández-Moya et al 2014, Jha 2014. Excessive nutrient export has been reported for teak plantations (Fernández-Moya et al 2011, 2014 and this could be related to the decline in productivity observed by some managers in the second Fernández- and/or third rotations (Kollert & Cherubini 2012).…”

“…Although this is a large loss in itself, the total nutrient extraction over one rotation is even larger as the timber extracted by thinnings, with a higher proportion of bark, also needs to be taken into account. Final felling nutrient extraction in teak plantations could be of special relevance in the case of P and K, because of their low soil availability (Fernández-Moya et al 2014). Due to the importance of teak plantations in Central American countries (Kollert & Cherubini 2012), this species was chosen in order to analyze possible solutions to nutrient export and soil depletion.…”

“…Hence, hypothetically, timber will have a higher nutrient concentration during the dry season (defoliated teak period), when timber extraction is usually performed, than in the growing season when nutrients will be allocated to foliage (Fernández-Moya et al 2014). Consequently, if this hypothesis is confirmed, modifying harvesting schedules would provide an efficient, cost effective approach to reducing nutrient export through timber harvesting.…”