Modelling dead wood in Norway spruce stands subject to different management regimes
ABSTRACT Strategies for preserving biodiversity in boreal forests should include the maintenance of coarse woody debris (CWD) because this substrate is a key feature for the preservation of many threatened species. Computer simulation programs are useful tools for predicting the amount of CWD that will arise if certain management practices are applied in the long term. We have constructed and used a simulation program based on stochastic equations, which aims at predicting the amount of CWD in homogenous stands of Norway spruce in central Scandinavia. Because the rate of tree mortality is a critical factor in such simulations, we present such data derived from spruce-dominated forests surveyed in the Swedish National Forest Inventory.A comparison between simulation outcomes and field data shows that the average quantity of CWD in today’s managed forest is possible to predict using the simulation model. If the forest is managed according to the Forest Certification Standard, the amount of CWD (diameter larger than 10 cm) will be almost three times higher as the amount in today’s managed forests. The amount of CWD was found to be highest in old stands and immediately after cutting. In stands of an intermediate age the amount of CWD was low, especially CWD in early decay stages and of larger sizes. High productivity and long rotation time tended, on average, to increase the amount of CWD in stands. Among the management practices recommended in the new biodiversity-oriented forestry, retention of small areas with living trees is the most efficient way to increase the average amount and continuous occurrence of CWD within a stand, at least if the retained areas are as productive as the main part of the stands.
- Alzheimer's & dementia: the journal of the Alzheimer's Association 07/2011; 7(4). · 14.48 Impact Factor
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ABSTRACT: Many species that depend on old trees and dead wood are suffering from habitat losses and intensive forest management. For the conspicuous cerambycid beetle Rosalia alpina, a relative sampling analysis combined with a distribution model showed a population decrease in Switzerland between 1900 and World War II. This negative trend can be ascribed to the abandonment of traditional management such as wooded pasture and to the expansion of high forest promoted by modern forestry. Since that period, the population of R. alpina, has been increasing and each single relict population of this species was maintained. These positive population trend can be explained by less intensive forest management and a shift from fuel-wood production to timber wood. Today, many more old beech trees and much more dead wood remain in Swiss forests than 50 years ago. Consequently, the habitat conditions necessary for the development of the Rosalia longicorn have improved, especially on steep terrain in colline and submontane regions. However, it is still uncertain whether current population sizes can guarantee the survival of this species in the long term, especially as fuel-wood production is expected to become more intensive in Switzerland in future decades. The conservation of this species requires, therefore, the establishment of natural forest reserves and dead wood islands or the restoration of wooded pastures with scattered habitat trees. The Rosalia longicorn could then act as an umbrella species for other species that depend on old trees and dead wood.Journal of Insect Conservation 17(4). · 1.80 Impact Factor
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ABSTRACT: – • Coarse woody debris (CWD) plays a substantial role in several ecological processes in forest ecosystems, providing a habitat for many organisms and participating in biogeochemical fluxes. Understanding CWD dynamics is important to classify adequate density, size and amount into different decay classes and to make decisions that include biodiversity and the carbon budget in practical forestry. – • A two-step model has been developed to quantify CWD in Pinus spp. plantations in Northern Spain. The two-step approach was composed of a logistic model to predict the probability of CWD occurrence and linear models to quantify the two components considered, basal area of snags and volume of logs. – • Site conditions, and climatic and stand variables were included in the models as independent variables. Good performance of the two-step model (R 2snag = 39.9%, R 2log = 62.8%) was observed. – • Modelling CWD is a useful tool for simulating future scenarios in the current context of climate change. Models inform stakeholders properly about defining the best silvicultural options for the distribution of CWD under sustainable forest management.Annals of Forest Science 01/2010; 67(7):708-708. · 1.63 Impact Factor