Quantifying disturbance effects on vegetation carbon pools in mountain forests based on historical data

Abstract

Although the terrestrial carbon budget is of key importance for atmospheric CO 2 concentrations, little is known on the effects of management and natural disturbances on historical carbon stocks at the regional scale. We reconstruct the dynamics of vegetation carbon stocks and flows in forests across the past 100 years for a valley in the eastern Swiss Prealps using quantitative and qualitative information from forest management plans. The excellent quality of the historical information makes it possible to link dynamics in growing stocks with high-resolution time series for natural and anthropogenic disturbances. The results of the historical reconstruction are compared with modelled potential natural vegetation. Forest carbon stock at the beginning of the twentieth century was substantially reduced compared to natural conditions as a result of large scale clearcutting lasting until the late nineteenth century. Recovery of the forests from this unsustainable exploitation and systematic forest management were the main drivers of a strong carbon accumulation during almost the entire twentieth century. In the 1990s two major storm events and subsequent bark beetle infestations significantly reduced stocks back to the levels of the mid-twentieth century. The future potential for further carbon accumulation was found to be strongly limited, as the potential for further forest expansion in this valley is low and forest properties seem to approach equilibrium with the natural disturbance regime. We conclude that consistent long-term observations of carbon stocks and their changes provide rich information on the historical range of variability of forest ecosystems. Such historical information improves our ability to assess future changes in carbon stocks. Further, the information is vital for better parameterization and initialization of dynamic regional scale vegetation models and it provides important background for appropriate management decisions. Keywords Forest carbon stock Á Terrestrial carbon sinks Á Windthrow Á Bark beetle Á Forest management Á Historical ecology

Application of a computationally efficient method to approximate gap model results with a probabilistic approach

“…Our total biomass results are also consistent with results of Erb (2004), who reported a PNV carbon mass of 12.4 kgC m −2 for Austrian forests. Furthermore, in a study where LPJ-GUESS was used locally for a valley in the Swiss Prealps, Gimmi et al (2009) also concluded that the actual biomass was slightly smaller than the assumed natural forest biomass.…”

Modelling natural disturbances in forest ecosystems: a review

“…Individual-based models were used to simulate the effect of wind events on local structure and forest dynamics (e.g., Rademacher et al, 2004;Papaik and Canham, 2006;Uriarte and Papaik, 2007). Similar approaches were incorporated into models operating at larger spatial scales (e.g., Moorcroft et al, 2001: ED;Gimmi et al, 2009). Spatially explicit forest landscape models (i.e.…”

Land-use and climate change effects in forest compositional trajectories in a dry Central-Alpine valley

“…in the valley bottom to the upper tree line at about 2 400 m a.s.l. These forests were chosen due to the excellent historical source availability, especially forest management plans which are a valuable source for reconstructing historic forest conditions and forest uses (Bürgi, 1999;Gimmi and Bürgi, 2007;Gimmi et al, 2009). …”