Retranslocation of foliar nutrients in evergreen tree species planted in a Mediterranean environment

Abstract

Internal nutrient recycling through retranslocation (resorption) is important for meeting the nutrient demands of new tissue production in trees. We conducted a comparative study of nutrient retranslocation from leaves of five tree species from three genera grown in plantation forests for commercial or environmental purposes in southern Australia--Acacia mearnsii De Wild., Eucalyptus globulus Labill., E. fraxinoides H. Deane & Maiden, E. grandis W. Hill ex Maiden and Pinus radiata D. Don. Significant amounts of nitrogen, phosphorus and potassium were retranslocated during three phases of leaf life. In the first phase, retranslocation occurred from young leaves beginning 6 months after leaf initiation, even when leaves were physiologically most active. In the second phase, retranslocation occurred from mature green leaves during their second year, and in the third phase, retranslocation occurred during senescence before leaf fall. Nutrient retranslocation occurred mainly in response to new shoot production. The pattern of retranslocation was remarkably similar in the leaves of all study species (and in the phyllodes of Casuarina glauca Sieber ex Spreng.), despite their diverse genetics, leaf forms and growth rates. There was no net retranslocation of calcium in any of the species. The amounts of nutrients at the start of each pre-retranslocation phase had a strong positive relationship with the amounts subsequently retranslocated, and all species fitted a common relationship. The percentage reduction in concentration or content (retranslocation efficiency) at a particular growth phase is subject to many variables, even within a species, and is therefore not a meaningful measure of interspecific variation. It is proposed that the pattern of retranslocation and its governing factors are similar among species in the absence of interspecies competition for growth and crown structure which occurs in mixed species stands.

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). This is in accordance with the previously discussed resorption process, as nutrients are retranslocated to the wood, bark, branches and roots when the leaves begin the senescence process (Van Den Driessche 1984, Aerts 1996, Fife et al 2008. This pattern is different to that of the foliar K concentration, which exhibits the resorption process slightly later (between January and February, as previously mentioned) and the greater increase in trunk concentration slightly earlier, between October and December ( Fig.…”

“…S1 in Supplementary material). This pattern has been observed by other authors, at least with regard to the lack of Ca retranslocation (Saur et al 2000, Fife et al 2008.…”

“…S1 in Supplementary material). This variation can mainly be attributed to the widely analyzed retranslocation processes (Van Den Driessche 1984, Aerts 1996, Fife et al 2008). In addition, litterfall nutrient concentration ( Fig.…”

Litterfall and nutrient return in moist evergreen broad-leaved primary forest and mixed subtropical secondary deciduous broad-leaved forest in China

“…A previous study has confirmed that the nutrient of twigs and leaves can be from soil via roots and from the atmosphere through stomata (Staaf and Berg 1981). For different forest stand species, seasonal fluctuations of N concentrations in green litterfall, with the maximum values in fresh leaves and the minimum values in old ones, have been reported in the literatures (Martínez-Alonso et al 2007;Hansen et al 2009;Fife et al 2008). Litterfall nutrient concentrations have also been related to other factors, such as soil nutrient availability, climatic and growth conditions (Binkley 1996;Augusto et al 2000).…”

“…By contrast, the lowest N concentrations in litterfall collected in autumn and early winter appear to be a strategy to reduce nutrient losses through retranslocation to the new tissue production or storage in twigs (Fife et al 2008). However, N showed a relative stable pattern in the primary forest, which may be significantly related to litterfall quality.…”