Stand and coarse woody debris dynamics in subalpine Norway spruce forests withdrawn from regular management

Abstract

Abstract• We studied structural characteristics, amount and quality of coarse woody debris (CWD), intensity of competition and mortality in two subalpine Norway spruce stands withdrawn from regular management. The stands, that we measured twice (in 1993 and 2005), have similar age and structure, but a different time has elapsed since the last silvicultural treatments (respectively 22 and about 55 y).• The main purposes were to analyze the current stage of development as compared to the old-growth one and to highlight the legacies of past management.• Although relatively old, the first plot (Valbona 1) was at the end of the pole stage. CWD was low in volume and was mainly of man-made origin (stumps). A recent thinning from below has reduced density-dependent competition and delayed the development of old-growth characteristics. The second plot (Valbona 2a) was at the beginning of the transition stage, with density-dependent and allogenic mortality both active at the same time. CWD volume was higher in plot Valbona 2a than in Valbona 1, but neither was comparable yet to the reference old-growth sites from Central Europe, both in quantity and in quality (e.g., decay rate continuity).• The effects of the past management were: (1) reducing the quality and quantity of the CWD, (2) alleviating competition, (3) increasing resistance to minor disturbances and, as a consequence, (4) delaying the development processes.• In mature or overmature subalpine Norway spruce stands withdrawn from regular management many decades are necessary to develop old-growth characteristics and a longer period of time is necessary to reach a true old-growth stage.

Stand structure and plant species diversity in managed and abandoned silver fir mature woodlands

“…However, woodlands inside strict forest reserves (MCPFE, 1998;Parviainen et al, 2000) have the potential to develop towards old-growth forests (Gilg, 2004) that have stand structures and features similar to those which preceded human disturbances (Schnitzler and Borleab, 1998;Parviainen et al, 2000;Motta et al, 2010). In addition because silviculture is often abandoned when unprofitable, such as in the Alpine and in the Mediterranean regions (Piussi, 1991;Fabbio et al, 2003;Pettenella and Secco, 2006), the area of unmanaged woodlands is expected to increase in the future.…”

Development of old-growth characteristics in uneven-aged forests of the Italian Alps

“…In the last decades, a gradual reversal of this trend has been observed, with a decrease in timber removal, and many forests have been withdrawn from management Motta et al 2010 ;Vandekerkhove et al 2009 ). At the same time, the scientific community has been advocating for forest management strategies that aim at the restoration of old-growth attributes that would benefit a wealth of taxa that are lacking or threatened in managed forests, even where close-to-nature forestry is applied (Lindenmayer and Franklin 2002 ;Lindenmayer et al 2006 ).…”

Influence of Spatiotemporal Dynamics on the Fine-Scale Spatial Genetic Structure of Differently Managed Picea abies Stands

“…Although a formal comparison of genetic diversity between managed and unmanaged stands of Norway spruce is virtually impossible in the Italian Alps due to the lack of unmanaged forests, our data showed negligible differences in genetic diversity and SGS among plots that have had a different recent history of forest management. The main difference in terms of recent forest management history is between VB3, a former wooden pasture, and VB1-VB2, both established about 200 years ago after a shelterwood felling and managed until 1984 and 1948, respectively [64]. A possible disadvantage of shelterwood management with respect to wood pastures is that natural regeneration originates mainly from a single seed year, determining that only a subset of adult trees could contribute to the post-intervention generation [9].…”