Changes in organic chemical components of needle litter during decomposition. Long-term decomposition in a Scots pine forest. I

Abstract

0 . THEANDER. 1982. Changes in organic chemical components of needle litter during decomposition: long-term decomposition in a Scots pine forest I. Can. J. Bot. 60: 1310-1319. The decomposition and organic chemical changes in Scots pine (Pinus silvestris) needle litter were studied for a period of 5 years and until 75% weight loss was reached in field incubation. The changes in components such as various groups of lipophilic extractives, low-molecularcarbohydrates, cyclitols, phenolic glycosides, polysaccarides, and lignin were followed. There was a great drop of sugars, steryl esters, and triglycerides during the 1st year of decomposition. Some isoprenoid alcohols, sterols, and some acids belonged to the most stable of the soluble components. Of the solid residue the arabinans decomposed rapidly, the cellulose decomposed somewhat faster than the hemicelluloses as a group, and the lignin decomposed rather slowly (about 48% in 5 years). I BERG, B., K. HANNUS, T. POPOFF et 0 . THEANDER. 1982. Changes in organic chemical components of needle litter during , decomposition: long-term decomposition in a Scots pine forest I. Can. J. Bot. 60: 1310-1319. La dCcomposition de la litiere d'aiguilles de pin sylvestre (Pinus silvestris) et les changements chimiques dans les composCs organiques de la litibre ont Ct C CtudiCs pendant une pCriode de 5 ans, et jusqu'a une perte en poids de 75% dans les incubations au champ. Les changements de divers types de composes chimiques ont Ct C suivis: extraits lipophiles, glucides de faible poids molCculaire, cyclitols, glycosides phCnoliques, polysaccarides et lignine. I1 y a une forte baisse des sucres, des stCryl esters et des triglyckrides au cours de la premibre annee de dCcomposition. Certains alcools isoprknoides, des stCrols et quelques acides sont parmi les plus stables des composCs solubles. Quant aux rCsidus solides, les arabinanes se dCcomposent rapidement, la cellulose se dCcompose un peu plus vite que l'hCmicellulose, tandis que la lignine se dCcompose plutBt lentement (environ 48% en 5 ans).[ Traduit par le journal]Introduction studies and comments on the effect of "chemicalLitter and humus are organic chemical c-ers of physical" quality of litter on decomposition there have nutrients and their decomposition appears to be the been very few studies on the decomposition of specific limiting process for the release of nutrients. However, chemical components Of litter. el in (1928) found that comparatively little is known about the ~ecomposition the percentage of nitrogen in litters strongly affected the of plant litter in nature. The chemical composition, both weight loss rate. He also suggested that decom~osition the inorganic and the organic, could be expected to be an is affected by other factors, among which tannins have important regulatory factor for the rate of the decompo-been assumed affect weight loss rate in Oak leaves sition process and some of the studies made have dealt (Ha"ison 1971). High levels Of lignin have a strong with decomposition versus the organic and...

Spectral Reflectance of Wheat Residue during Decomposition and Remotely Sensed Estimates of Residue Cover

“…Similar patterns of changes in fiber composition also occurred in the weathered outer layers of large round bales of hay stored outdoors [38] and in forest ecosystems during the early stage of litter decomposition when environmental conditions were major controlling factors [5]. The onset of mass loss due to degradation of cellulose and hemicellulose began rapidly in pine litter, but the first net loss of lignin mass was after 2 years [39]. The reflectance spectra of dry wheat straw at selected DD (Figure 4) illustrate the subtle changes in spectrum shape as the wheat straw decomposed.…”

Disruption of root carbon transport into forest humus stimulates fungal opportunists at the expense of mycorrhizal fungi

“…Litter saprotrophs in the boreal forest are nitrogen limited (Boberg et al, 2008) and little net release of nitrogen seems to take place during the early, saprotrophic stages of decomposition (Berg et al, 1982). Instead, nutrients are recycled to plants from more degraded litter and humus (Melillo et al, 1989;Lindahl et al, 2007).…”

Alterations in forest detritus inputs influence soil carbon concentration and soil respiration in a Central-European deciduous forest

“…Decreased soil C could also be due, at least in part, to elevated rates of decomposition enhanced by higher soil moisture in plots without roots (and thus without transpirational water losses) in these dry forests. We expected woody debris to have a greater effect on soil C levels than leaf litter, given that leaves are likely to decompose more quickly than woody tissue (Harmon et al, 1986) and enter the soil C pool (Berg et al, 1982), however, leaf litter addition (DL) increased SOC concentration in the upper soil layer to a greater extent than did a similar amount of woody debris (branches, twigs, bark). The effect of wood debris, therefore, might not be observed in the first decade.…”