Litterfall and litter decomposition in chestnut high forest stands in northern Portugal

Abstract

This research aimed to: estimate the inputs of litterfall; model the decomposition process and assess the rates of litter decay and turnover; study the litter decomposition process and dynamics of nutrients in old chestnut high forests. This study aimed to fill a gap in the knowledge of chestnut decomposition process as this type of ecosystems have never been modeled and studied from this point of view in Portugal. The study sites are located in the mountains of Marão, Padrela and Bornes in a west-to-east transect, across northern Portugal, from a more-Atlantic-to-lessmaritime influence. This research was developed on old chestnut high forests for quality timber production submitted to a silviculture management close-to-nature. We collected litterfall using littertraps and studied decomposition of leaf and bur litter by the nylon net bag technique. Simple and double exponential models were used to describe the decomposition of chestnut litterfall incubated in situ during 559 days. The results of the decomposition are discussed in relation to the initial litter quality (C, N, P, K, Ca, Mg) and the decomposition rates. Annually, the mature chestnut high-forest stands (density 360-1,260 tree ha -1 , age 55-73 years old) restore 4.9 Mg DM ha -1 of litter and 2.6 Mg ha -1 yr -1 of carbon to the soil. The two-component litter decay model proved to be more biologically realistic, providing a decay rate for the fast initial stage (46-58 yr -1 for the leaves and 38-42 yr -1 for the burs) and a decay rate related to the recalcitrant pool (0.45-0.60 yr -1 for the leaves and 0.22-0.36 yr -1 for the burs). This study pointed to some decay patterns and release of bioelements by the litterfall which can be useful for calibrating existing models and indicators of sustainability to improve both silvicultural and environmental approaches for the management of chestnut forests.Key words: Castanea sativa Mill.; decomposition rate; turnover; nutrient use efficiency; double exponential model. Resumen La hojarasca y su descomposición en bosques de castaño de monte alto en el Norte de PortugalEsta investigación tuvo como objetivo calcular los aportes de hojarasca; modelar el proceso de descomposición y evaluar las tasas de descomposición de la hojarasca y el turnover; estudiar el proceso de descomposición de la hojarasca y la dinámica de nutrientes en bosques de castaños de monte alto. Asimismo, se quiso llenar un vacío en el conocimiento del proceso de descomposición del castaño ya que este tipo de ecosistemas no han sido modelados y estudiados desde este punto de vista en Portugal. El estudio se realizó en las montañas de Marão, Padrela y Bornes situados en un transepto que va de oeste a este, en el norte de Portugal, de mayor a menor influencia Atlántica. La investigación se desarrolló en bosques de castaños antiguos dedicados a la producción de madera de calidad sometida a una gestión silvícola cercana a la naturaleza. Se emplearon colectores de hojarasca y se estudió la descomposición de hojarasca y erizos mediante el empl...

The effect of Jatropha curcas L. leaf litter decomposition on soil carbon and nitrogen status and bacterial community structure (Senegal)

“…The double exponential decomposition model was a good fit with C mineralization data. It showed that C was divided into 28% labile C and 72% recalcitrant C. The decomposition rate for the labile component (k 1 ) was higher than that for the recalcitrant component (k 2 ) which agrees with the litter decomposition dynamics reported by Patrício et al (2012). The rate of decomposition of recalcitrant compounds plays a key role in organic matter sequestration.…”

“…The carbon loss data were also fitted to the double exponential decomposition model of Wider and Lang (1982) used in previous studies (Beyaert and Voroney, 2011;Staelens et al, 2011;Patrício et al, 2012).…”

“…J. curcas is a perennial plant belonging to the Euphorbiaceae family with poisonous seeds and leaves. Wani et al (2012) estimated that the accumulated leaf fall from a 3 to 5 year old J. curcas plantation added 1450 kg ha −1 of carbon to the soil, 800 kg of this from the leaves, suggesting that leaves can recycle soil organic matter and nutrients (Patrício et al, 2012).…”

Decomposition and nutrient release pattern of wheat (Triticum aestivum) residues under different treatments in desert field conditions of Sudan

“…where W t = Weight remained after each sampling week (g) and, W 0 = Initial weight (g) which is potentially decomposable The data for dry mass remaining from each treatment were fitted to a negative exponential model (Olson 1963): Exponential decomposition models have been extensively used to describe the decomposition of litter in litter bags (Patricio et al 2012):…”

Carbon sequestration for different management alternatives in sweet chestnut coppice in northern Spain

“…Leaf turnover was estimated considering that all leaves fall in 1 year because sweet chestnut is a deciduous species (value equal to 1). Branch turnover was calculated considering that a value of 0.40 Mg ha -1 of carbon was provided to the soil (Patricio et al, 2012). Stem fraction was evaluated directly and the trees which had fallen between the taking of the inventory and the census of dead trees were also included.…”