Decay rates of woody debris were estimated and used to model the decay of various diameters of branches and stems in a beech stand in Central Germany. In addition, use of wood density, volume and mass loss to quantitatively describe the degree of decay was tested. The mass loss during decay could be described by a simple exponential function. Under the presented climatic conditions, beech coarse woody debris (CWD) with a diameter [10 cm decays completely in about 35 years. In the first 8 years of decay the mass loss is determined by the decrease in wood density, and subsequently by the loss in volume. Estimation of wood density allows the first three of the four classes of decay to be distinguished, while trees in the last two decay classes could be distinguished using wood volume. Beech fine woody debris with a diameter between 1 and 10 cm decays within about 18 years. The litter fraction of \1 cm is part of the humus layer after 4 years. If there are goals for the amounts, types and dimensions of woody debris to be provided for conservation of biological biodiversity and other ecological functions in managed beech forests, this study offer indications for how long existing woody debris can meet its functions and how frequent new input of CWD is required.

To evaluate the importance of nutrient fluxes via leaching from coarse woody debris (CWD) in an area with high atmospheric nitrogen (N) inputs, throughfall and CWD leachate from logs at different stages of decomposition were investigated over a period of 14 and 27 months, respectively, in a 160-year-old European beech ( Fagus sylvatica L.) forest in northwestern Germany. Water samples, collected from 30 zero-tension lysimeters installed in pairs along 15 logs and from 27 neighboring raingauges, were chemically analyzed in the laboratory. Generally, as CWD decay advanced, the ratio of leachate to throughfall decreased, and the amount of dissolved nutrients in the leachate increased. With the exception of ammonium (NH4+) and dissolved inorganic carbon, the element concentrations in the CWD leachate were significantly higher than those in the throughfall. The concentrations of NH4+ and nitrate (NO3–) in the CWD leachate, which were very high compared with values from North American studies, were caused by the continuously high atmospheric N inputs, and the resulting N saturation in the forest ecosystem investigated. The low concentrations of the cations calcium and magnesium indicate that at this site nutrients limiting plant and fungal growth are retained and accumulated in the CWD.

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Los bosques de roble (Nothofagus obliqua), en el centro sur de Chile, constituyen masas forestales relativamente homogéneas, de fácil acceso, de buen crecimiento y madera de valor, razón por la cual son frecuentemente manejados con los incentivos mediante la ley de bosque nativo. El sistema silvícola que se ha implementado en estos bosques, por sobre otros métodos, es el del manejo de árbol futuro. En el presente estudio se entrega una propuesta para la decisión del momento de cosecha, a través de la definición de un diámetro meta para los árboles futuro que permita optimizar el beneficio económico. La metodología ocupada se basa en un modelo de cálculo de rentabilidad que propone que los ingresos adicionales por la madera, que se producen por el crecimiento del árbol, deben compararse con el interés adicional de esperar año a año para alcanzar un diámetro meta. Se aplicó este método en dos rodales de roble de la región de Los Ríos. Los resultados mostraron que el diámetro meta puede variar entre 34 y 46 cm, según la tasa de rentabilidad esperada y la condición inicial del rodal, expresada en la distribución diamétrica de los árboles futuro. Entre más alta era la rentabilidad esperada, más bajo el diámetro meta.