Holzerntepotenzial im Schweizer Wald: Simulation von Bewirtschaftungsszenarien

Abstract

Timber-harvesting potential of Swiss forests: simulation of management scenarios Growing stock in Swiss forests has, during the past 10 years, increased by 3% overall, with large regional variation. The increase in Alpine regions has been considerable, while growing stock has decreased on the Plateau. We simulated 5 different 100-year management scenarios with the forest development model Massimo. In the base scenario “constant growing stock”, 7.7 million m3 of merchantable timber could be harvesting annually. In the scenario “increasing growing stock”, the harvesting potential was lower (6.3 million m3), but it was higher in the scenarios “continually high increment” (7.8 million m3), “high demand for coniferous timber“ (8.5 million m3) and “high demand for wood fuel or chemical timber” (8.1 million m3). With time, timber-harvesting costs increase for all scenarios, with the least increase for the base scenario. If the prevailing management system continues (scenario “increasing growing stock”), stands will become denser and growing stock increase, with the risk of more disturbances, e.g. wind, snow-breakage, or bark beetles. In the Plateau, however, the regional overuse of recent decades could limit the overall timber-harvesting potential. In Alpine regions, stabilizing growing stock (scenario “constant growing stock”) could improve the resistance of forests, but the harvesting costs per cubic meter might be higher. These management scenarios provide decision makers with indications of how particular forest management strategies could affect the development of growing stock, harvesting amounts and costs.

Trade-offs between ecosystem service provision and the predisposition to disturbances: a NFI-based scenario analysis

“…The 1 km sampling grid of NFI1 encompassed 10,981 sample plots and the 1.44 km grid of NFI2, NFI3 and NFI4b encompassed 6412, 6608 and 3376 sample plots (Abegg et al 2014b). The model simulations by Stadelmann et al (2016), on which this study builds, were initialized with data from the 5086 sample plots that have been resampled both in NFI2 and NF3 ( Fig. 1).…”

“…These guidelines encompass phytosociological but also silvicultural criteria. The scenarios also account for harvesting restrictions (no shelterwood cuts) in protection forests (Stadelmann et al 2016;Temperli et al 2017a).…”

“…In 2014, when Stadelmann et al (2016) set up the simulations, the data from NFI2 and NFI3 were the most recent complete and consecutive NFI samples and constituted the 5086 sample plots that were used to initialize MASSIMO. To approximate forest conditions in 2016, simulated harvests in MASSIMO were iteratively adjusted until simulated growing stocks matched the most recent observations of 2013 (NFI4b).…”

“…National policies and previous assessments of potential future timber availability in several Central European countries, including Switzerland, consider scenarios of increased timber harvesting. The goal is to promote local wood use as a CO 2 -neutral construction material and source of energy and to therewith support local forest industry, sequester carbon and substitute fossil fuels (Federal Office for the Environment FOEN 2013;Nabuurs et al 2015;Stadelmann et al 2016;Jandl et al 2018). These "climate-smart" forest management policies contrast with recent developments of increasing growing stocks in poorly accessible mountain regions where profitable commercial logging is difficult due to high harvesting costs (Brändli and Röösli 2015;Taverna et al 2016;Yousefpour et al 2018).…”

“…We used data from the Swiss National Forest Inventory (NFI) and tree-level output data from the NFI-based forest development model MASSIMO to calculate ecosystem service provision and disturbance predisposition. MASSIMO was applied in a previous project to predict growing stock, increment and potential timber harvests under business as usual (BAU) management and four scenarios of increased timber harvests (Stadelmann et al 2016). Specifically, we asked: 1) does increasing timber yield trade-off with disturbance predisposition?…”