Nutrient cycles in pine and their adaptation to poor soils

Abstract

Values for the various fluxes of nitrogen through the tree–soil system were calculated using models derived from measurements of rates of input, accumulation, and transfer in plots of 11-m-tall Pinusnigra var. maritima (Ait.) Melv. that were showing growth responses to varying rates of nitrogen fertilizer. As the result of continuing immobilization in trees and humus, growth of the unfertilized trees was declining and the trees were having to sacrifice older tissues to mobilize sufficient nitrogen for new growth. In the fertilized trees, there was similar mobilization but of excess nitrogen stored during the period that fertilizers were applied. Models of the flux of nitrogen, phosphorus, calcium, and magnesium at optimum growth showed that tight cycling and low rates of immobilization, coupled with effective retention of relatively high atmospheric inputs, probably represents the adaptive mechanism that enables trees to thrive on soils low in potassium and magnesium. However, high rates of immobilization and low rates of atmospheric input relative to tree uptake mean that despite the maintenance of tight cycles, the trees continued to make significant demands on soil reserves of nitrogen, phosphorus, and calcium throughout their life cycle.

Age-related nutrient content and carbon isotope composition in the leaves and branches of Quercus aquifolioides along an altitudinal gradient

“…As the whole plant is composed of tissues of different ages, in which the nutrient contents are not evenly distributed, the lower accumulation of N, P, K and Mg, both on a dry mass basis and on a unit area basis, with increasing leaf age can be explained by the nutrient availability and the mobility within the trees (Miller et al 1979;Saur et al 2000;Zas and Serrada 2003). It has also been reported that the contents of these nutrients are generally highest in the actively growing parts of the trees (e.g., leaves) and lowest in the structural and not actively growing parts (e.g., stem wood) (Wang et al 1996;Wang and Klinka 1997;Laclau et al 2001).…”

Nitrogen uptake, partitioning and internal cycling in Picea sitchensis (Bong.) Carr. as influenced by nitrogen supply

“…Tbe Storage atid seasonal intertial cycling of nitrogen (N) bas been sbovvn to be importatit for tbe sustainable growtb of evergreen trees (Miller et al, 1979;Rapp, Leclerc & Lossaint, 1979;Millaid & Proe, 1992). In conifers, N is stored duritig tbe winter in needles and remobilized in tbe spring duritig tbe growtb of new foliage, as sbowti by N budget studies (Turner, 1977;Ericsson et al, 1985, Nambiar & Fife, 1987Heltnisaari, 1992a, b) and tbe use of ""N to quantify internal cycling directly (Millat-d & Pioe, 1992), Nitrogen budget studies bave sbowti tbat enbanced site fertility increases tbe capacity for ititertial cycling (Miller et al, 1979), tbrougb increasing needle mass atid so tbe capacity for N storage (Nambiar & Eife, 1987;Heltnisaari, 1992«), Eew studies bave considered tbe impact of nutrient supply oti tbe efficieticy of tbe processes of internal cyclitig.…”

Age-related changes of leaf traits and stoichiometry in an alpine shrub (Rhododendron agglutinatum) along altitudinal gradient

“…Previous researches showed that, lower accumulation of nutrients (N, P), both on a dry mass basis and on a unit area basis, with increasing leaf age, can be explained by the nutrient availability and the mobility within the trees (Miller et al 1979;Saur et al 2000;Zas and Serrada 2003). Generally, contents of nutrients are higher in more actively growing parts of trees like leaves and fine roots (Wang et al 1996;Wang and Klinka 1997;Laclau et al 2001).…”