Modelling near-natural silvicultural regimes for beech - an economic sensitivity analysis

Near-natural silvicultural regimes for beech (Fagus sylvatica L.), in the f orm of uneven-aged selective felling, receive increasing interest in Denmar k. This is partly due to the ability of this system to preserve the forest climate and maintain important ecological functions such as bio-geochemical cycling and biodiversity conservation. The optimal age to convert from eve n-aged management to uneven-aged selective felling seems to be as early as possible, about 55 years, when sufficient natural seeding can be expected. A fixed conversion period of 100 years is assumed. This regime, here analys ed by the use of a so-called chessboard model, appears to be economically s uperior to clear felling if the regime is initiated in medium-aged stands d own to the age of 55 years, assuming a high site quality and a real discoun t rate of 3% per annum. Uneven-aged selective felling seems to be economica lly superior to even-aged natural regeneration, assuming that: (i) the stum page prices of regeneration harvests are increased by 10%, or (ii) the diam eters of regeneration harvests exceed those of even-aged management by abou t 17% simultaneous with an identical increase of the maximum stumpage price . Clear felling seems to be the more profitable regime only if: (i) the sta nd is close to the economic optimal rotation age for clear felling, and (ii ) when the stumpage prices of regeneration harvests achieved by use of the uneven-aged selective management regime are reduced by 10% or more due to q uality defects caused by prolonged rotation ages. The above results are sen sitive to variation of stumpage prices, but less so to variation of regener ation costs associated with near-natural management systems. However, the n ear-natural silvicultural regimes may be unable to fulfill the liquidity ob jectives following from the application of traditional management systems. (C) 2000 Elsevier Science B.V. All rights reserved.