Effects of silvicultural treatment on the stability of black pine plantations.

Black pine plantations have been established at the purpose of recovering a forest cover to marginal soils, mostly throughout the Apennines range in Italy, since the end of the eighteenth century and up to the mid 1900. Both the decay of forest cover and soil erosion were the outcome of the long-lasting overuse through the intensive forest exploitation practices, grazing of the forest floor and wildfires, occurring since many centuries ago. The primary function of pine reafforestation was therefore to re-establish a first cover with a pioneer species, preparatory to future mixed forest types based on the natural reintroduction of broadleaves originally living in the same areas, mainly deciduous oaks and beech in the upper part. These goals have been partly met over the wide reafforestation area; the key functions of pine stands are today the protection against soil erosion and the hydrological regulation of catchments. The pine stands have been assuming today also a scenic role because they have been incorporated in the landscape physiognomy. A series of thinning up to the regeneration phase had been planned by foresters since the design of these plantations, but many stands have grown unthinned and fully stocked for a long time, this condition contributing a less mechanical stability of trees. Alternative forms of regeneration in grown-up stands have been and are being tested to improve both the natural and artificial establishment of indigenous species, but thinnings remain, even if a tardy measure, the main practice enforceable to these pine forests. The results of experimental trials undertaken in the black pine forest stand located in Pratomagno casentinese (Arezzo) are being reported in the paper. The study started in 1978 and the following theses were tested (A) heavy thinning from below; (B) moderate thinning from below; (C) control. Three thinnings were carried out in 1978, 1999 and 2009 at the ages of 24, 45 and 55. The action over time of each intervention on the mensurational and mechanical stability parameters (H/D ratio H/Ddom ratio), are being analyzed. The stability parameters of the pine forest after three interventions (H/D ratio, crown ratio, horizontal crown projection and eccentricity of the crown) have been also analyzed on a sample of trees per thesis and compared with those of trees grown in absence of competition. Sampled trees were sorted per social class. Results proved that type, interval and intensity of thinning related to the age of intervention are the main determinants of a successful treatment. Thinnings from below increase individual stability over time only when also trees living in the main crop layer are being removed. The trials showed the improvement of stability parameters following the intermediate thinning applied at the age of 45. The thesis of heavy thinning had the best performance as for the awaited purpose

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

 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

Early and long-term impacts of browsing by roe deer in oak coppiced woods along a gradient of population density

Over the last few decades, wild ungulate populations have exhibited relevant geographic and demographic expansion in most European countries; roe deer is amongst the most widespread ungulate species. The increasing roe deer densities have led to strong impact on forest regeneration; the problem has been recently recognized in coppice woods, a silvicultural system which is widespread in Italy, where it amounts to about 56% of the total national forested area.In this study we investigated the effect of roe deer browsing on the vegetative regeneration of Turkey oak few years after coppicing, along a gradient of roe deer density. A browsing index revealed that browsing impact was high at any given roe deer density but increased at higher density, with the browsing rate ranging from 65% to 79%. We also analyzed the long-term impact of browsing six and eleven years after coppicing under a medium roe deer density. Results indicated the early impact are not ephemeral but produced prolonged impacts through time, with an average reduction in volume of -57% and -41% six and eleven years after coppicing, respectively. Based on these results we proposed integrating browsing monitoring with roe deer density estimation to allow identifying ungulate densities which are compatible with silvicultural and forest management objectives. The proposed browsing index can be regarded as an effective management tool, on account of its simplicity and cost-effectiveness, being therefore highly suitable for routine, large scale monitoring of browsing impact

Roe deer browsing effects on growth development of Turkey oak and chestnut coppices.

Over the last three decades wild ungulates populations in Italy increased to values ranging from 300% to 600%. As a consequence, in Italy as well as in other European countries, situations with high ungulate density and, then, negative effects on the stability and dynamics of ecosystems, are increasing frequently. Starting from these evidences we investigated the effects of roe deer population on the vegetative regeneration of two different broadleaved tree species: Turkey oak (Quercus cerris L.) and chestnut (Castanea sativa Mill.) coppice stands. In Alpe di Catenaia (Apennines – Central Italy), after coppicing in 2002, we chose six experimental areas where fenced (P) and non-fenced (NP) plots were established. Measurements were performed at the beginning of the study period and in winter 2008 in both P and NP plots. Diameter and    height of all sprouts were measured. Results showed a different impact of roe deer on the two species. After seven years chestnut did not show any significant browsing-related damage, while in Turkey oak heavy differences between protected and non-protected areas are present: in NP plots roe deer browsing has produced a significant reduction in basal area (58%) and volume (57%) compared to P plots. The results agree with previous studies and confirm: (a) a selective browsing pressure on Turkey oak; (b) the lasting effect of the early impact after clear cutting, visible even seven years after. Based on the findings, we discussed the need for an integrated management of forest vegetation and forest fauna which should define the density of ungulates not only according to the theoretical carrying capacity    of ecosystems, but also considering (i) the preservation of the ecosystem overall functionality, (ii) the forest structure development and (iii) the forest management type

Enhancing chestnut coppices: silvicultural management and socio-economic context.

 Castanea sativa is one of the most important species for timber production in Italy but, both management system, ownership type and wood chain structure, aren’t able to  enhance enough the market value of wood assortments. Although the high demand of quality timber, the internal production is heavily  reduced, mainly as far as timber quality is concerned and because of the lack of suitable timber sizes. In this context, experimental trials  have been approached to identify and verify which silvicultural methods are best suited to reach high yields depending to the investments  needed and the local socio-economical condition. Two technical approaches were evaluated: stand silviculture and single-tree oriented silviculture. As for the socio-economical aspects, a few demographic indexes have been examined and the first-phase processing enterprises  acting in the concerned area were analyzed. The goals of this paper are to evaluate the biological response to the applied silviculture, to  analyze the problems arisen and to estimate the applicability of the proposed methods in relation to the different socio-economic contexts. The research has been carried out in Tuscany in two important forest areas - Monte Amiata and Colline Metallifere - in young chestnut  coppices characterized by an homogeneous stand density and a good site index. The two examined districts showed some similarities  but they have mainly highlighted important differences about the social structure and concerns and enterprises characteristics. The area of Monte Amiata is typified by a higher residents density then the Colline Metallifere but only 1/3 of the population is employed in the agro-forest sector. In addition, in the Monte Amiata district most concerns are sized less than 2 hectares and chestnut is the main forest  species. On the contrary, in the Colline Metallifere the agro-forest sector (57% of workers) is one of the main sources of income for the  local communities and medium-sized concerns are noteworthy present. Chestnut stands have here a marginal role, oaks are dominant  and the prevailing assortment is firewood. From a silvicultural viewpoint, both the studied areas showed a quite good potentiality, suitabl