Organic matter and nitrogen dynamics in a mature forest of common beech in the Sierra de la Demanda, Spain

Abstract

-Aboveground biomass, litterfall, leaf weight loss due to decomposition, N return and seasonal leaf N dynamics were studied in the Sierra de la Demanda, Spain, a Mediterranean climatic zone. The forest ecosystem considered was a climax beech (Fagus sylvatica L.) forest. Aboveground biomass was estimated by cutting and weighing seven trees from a beech stand according to diameter classes, recording the categories of trunk, branches and leaves. The results indicate a total biomass of 132.7 Mg ha -1 . The litterfall was 4 682 kg ha -1 yr -1 , although variations from year to year were observed, mostly due to water stress in summer. Greater K (Jenny's constant) and K o (Olson's constant) values were obtained for total litter than for leaves alone. It is possible that the mean soil humidity might not be a limiting factor in the decomposition process and that this effect would be due to the distribution of rainfall rather than to the total amount of precipitation together with elevated temperature and airing of the holorganic soil horizon. The leaf N contents of beeches growing in the Sierra de la Demanda were studied, relating the contents to other structural stand characteristics. For this, N was analysed in shed leaves, in leaf biomass and in leaves decomposing on a test plot in the "Tres Aguas" beech forest. Leaf nitrogen contents were measured over a vegetative cycle in the above beech forest. Finally, leaf nitrogen contents were studied in thirty beech stands in the Sierra de la Demanda located at different altitudes. Annual nitrogen accumulation in leaf biomass was 79.4 kg ha -1 yr -1 , of which 22.9 kg ha -1 yr -1 were returned to the soil substrate through shedding and 2.1 kg ha -1 yr -1 were actually incorporated into the soil. Nitrogen cannot be a limiting factor for the development of the beech stands studied because all of them surpassed the leaf deficiency threshold. Only other factors such as soil texture and structure or silvicultural treatment have a decisive effect on the production of the stand studied. The correlations for leaf nitrogen contents and the structural stand characteristics explored revealed that leaf nitrogen was only slightly correlated with the mean height of the trees at the plot. aboveground biomass / litterfall / weight loss / nitrogen / forest ecosystem Résumé -Dynamique de la matière organique et de l'azote dans une hêtraie de la Sierra de la Demanda (Espagne). La biomasse aérienne, la retombée de litière, la perte de poids de feuilles en décomposition, le retour et la dynamique saisonnière de l'azote des feuilles, ont été estimés dans une hêtraie (Fagus sylvatica L.) de la Sierra de la Demanda, (Espagne). La biomasse a été estimée par coupe et pesée de sept arbres selon la distribution des diamètres. Les poids des troncs, branches et feuilles ont été mesurés. Les résultats indiquent une biomasse totale de 132,27 Mg ha -1 . La chute de litière est de 4 682 kg ha -1 an -1 , cependant on a observé des variations inter-annuelles, principalement dues au stress hydrique esti...

Producción De Hojarasca Y Retorno De Nutrientes Vía Fliar en Un Matorral Desértico Micrófilo en El Noreste De México

“…These percentages are within the ranges reported by Caritat, García, Lapeña, and Vilar, (2006), Santa Regina (2000), Santa Regina and Tarazona (2001a) and Santa Regina and Tarazona (2001b), who found that leaves accounts for 50-80 % of all litwho found that leaves accounts for 50-80 % of all litterfall components in various ecosystems. Several studies (Domínguez, 2009;González et al, 2008;López et al, 2013;Rodríguez, 2010) reported leaf depositions ranging from 40-86 % in ecosystems similar to that used in the present study.…”

Litter production in an Atlantic beech (Fagus sylvatica L.) time sequence

“…Shifts in the time of litter fall result in the leaves (and another components) finding different conditions on the soil surface (microclimate, micro-organisms biomass etc.). Litter quality affects not only the rate of mass loss, but also the patterns and rates of nutrient immobilisation or release [38].…”

Sustainable development and management of beech forests

“…У зависности од добијених модела, користе се друге једначине, у којима су, као независни параметри, D 2 H, HD 2 , итд., гдје је H -висина стабла у метрима (Nihlgård 1972;Duvigneaud et al 1977;Bartelink 1997;Pretzsch 2000;Le Goff and Ottorini 2000;Santa Regina and Tarazona 2001;Cienciala et al 2005;Calamini and Gregori 2013). Регресијски коефицијент тежи вриједности 2,67, док регресијска константа варира у зависности од еколошких услова (Zianis and Mencuccini 2004).…”