Deadwood density variation with decay class in seven tree species of the Italian Alps

Forest deadwood is an important indicator of the biodiversity level because it provides habitat for many species. A wide range of plants and animals is strongly associated with standing and lying deadwood. Deadwood is also a fundamental component of nutrient cycles, regulates water flows, prevents soil erosion and contributes to carbon storage in the forest. In consideration of this last aspect a method is proposed to sample and analyse wood density in deadwood (standing and lying) at different rates of decay. The wood density provides valuable information needed to calculate carbon content of the deadwood. The method has been applied on seven alpine forest species (fir, spruce, Swiss pine, black European pine, Scots pine, European larch and beech) localized in several valleys of Trentino province in north-east Italy. Laboratory analysis of the sample deadwood determined the moisture content, fresh density and dry density. Moisture content was significantly higher in logs than in snags; moreover, this value decreased from the first to the third decay class and thereafter increased from the third to the fifth class. The dry density decreased at a constant rate from lower to higher decay classes. For all species the maximum percentage of dry density reduction is found between the fourth and the fifth decay classes. This study provides a preliminary data set on deadwood density, above all taking into account the increasing importance of the carbon content closely connected with this attribute.