Stand dynamics of a beech coppice beyond the rotation age and under conversion into high forest.

Abstract

 One of major issues dealing with forest management in Italy is the lack or the suspension of silvicultural practices over an increased share of the forest area, in progress since a few decades ago. The abandonment of rural areas, the emerging environmental functions being nowadays addressed to natural resources, include also many forests and management systems formerly devoted mainly to wood production. This occurrence has its major evidence on coppice forests, i.e. about a half of the country forest area and the forest type historically submitted to the more intensive management practices. The results of an experimental trial started in 1972 in a beech coppice aged 27, i.e. a few years after the age of traditional rotation, comparing the natural evolutive pattern as well as the silvicultural practices aimed at its conversion into high forest, are here reported. The trial included the control thesis and three different thinning intensities. Each thesis was arranged within the same thinning type, taking into account the volume of former standing crop in each plot. The analysis includes the growth pattern and the dynamics of stand structure in the populations under natural evolution and under conversion into high forest. Four inventories were carried out since 1972 at each decade up to 2002. Three thinnings were undertaken within the same time. Results show that both the tested management options, alternative and/or complementary to the traditional coppice system, are based on reliable biological assumptions. The natural evolutive pattern highlights the growth trend at ages older than those monitored under the coppice system. Beech shows a peculiar behaviour in the range observed due to its specific shade-tolerance. The shoot population reveals a sustained growth between the ages of 30 to 40; then, the occurrence of a heavy, regular mortality up to 50; finally, the recovery of a high growth rate up to the age of 60 (ending of the monitored period at now). Such growth pattern moves up the current volume increment, delays its intersection to mean increment and postpones substantially the age of growth rates culmination. The observed trend deviates from the canonical stand growth pattern and seems to be grounded on beech auto-ecology. This extends the time of reaction between the opposite feedbacks of mortality and growth and allows monitoring a likely different behaviour ruling ageing coppice growth. The same occurrence had not been highlighted before studying light-demanding species (deciduous oaks in the case) under the same stand types, these species being able to settle much more rapidly the cycle mortality-growth recovery-incremental culmination. The thesis of conversion into high forest provides the technical cultivation rules (type, intensity and interval of thinning repetition) and suggests it as enforceable also in the private domain due to the shortly-repeated harvestings and intermediate volumes that make each intervention profitable. The basic outcomes of the applied silvicultural practices are (i) the early crown shaping of shoot dendrotypes; (ii) the modeling of clustered stand structure; (iii) the individual development of well-balanced trees, more suited to tackle the grown-up and mature stages till the time of regeneration from seed, ending of the transitory cycle

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