Assessing the mechanical stability of trees in artificial plantations of Pinus nigra J. F. Arnold using the LWN tool under different site indexes

In young black pine plantations, the most valuable and interesting thinning scheme is mainly based on the positive selection of dominant and well-shaped trees to be candidates for carbon sequestration, timber production and natural regeneration. The mechanical stability of candidate trees is here a fundamental skill that must be taken into account and the slenderness ratio (HD) is one of the main indicators. HD has been recently proved to be correlated to the living whorl number (LWN) by Cantiani & Chiavetta (2015). In this study, the statistical model was re-calibrated in order to study the influence of soil fertility on the HD - Living whorls number (LWN) relationship.The fertility-balanced models estimated a different LWN threshold. The model for the highest fertility class (Site index 24) estimated 12 LWN (RMSE of 20%). Similarly, a lower value were detected for the other two fertility classes, SI20 and SI16, where 10 LWN were considered enough with an associated RMSE of 16% and 17% respectively. Compared to the general model provided by Cantiani & Chiavetta (11 LWN with 18% of RMSE) the site index approach improved the accuracy and reliability

Effect of Thinning on Forest Scenic Beauty in a Black Pine Forest in Central Italy

Forest management practices determine changes in stand characteristics and consequently influence public perception of forest scenic beauty visually appreciated by visitors. To understand the relationship between forest management practices and public perception, the present study evaluated the effects of thinning on the forest scenic beauty analyzing visitors' preferences towards images of forest managed in different ways. The investigation was implemented in a black pine (Pinus nigra spp.) forest located in Central Italy, where a designed thinning experiment was conducted during the winter of 2016. Silvicultural interventions were based on three options: traditional thinning (medium-intensity thinning from below), selective thinning, and absence of intervention (control). Then, through the face-to-face administration of a questionnaire to a sample of 200 visitors, visitors' aesthetic preferences for stands' characteristics affected by management interventions were assessed. The survey also investigated the perception of the effect of silvicultural treatments on the scenic beauty using pairwise comparison method. Results evidence a strong relation between scenic beauty and forest attributes. In particular, the results show that visitors prefer mixed forest with varying tree heights and layers, and consequently a high and variable quantity of light reaching the soil. Results also show that visitors prefer managed forests, and both kinds of thinning have a positive effect on the scenic beauty

Application of Innovative Silvicultural Treatments in Pine Forests

Pine forests—as natural stands and artificial plantations—are one of the most extended and common forest types in the world [...

La gestione dei rimboschimenti di pino nero appenninici. I diradamenti nella strategia di rinaturalizzazione

Management of black pine stands in the Appennines. Thinning for renaturalisation - The first stages of management and renaturalisation of black pine plantations are founded on thinnings, which are primarily aimed at increasing physical stability and creating favourable ecological conditions for the natural regeneration of autochthones species. The research aims at experimenting two different intensities in the first thinning of a black pine young stand of good fertility in the area of Pratomagno (Arezzo). The effects of the thinning on the main dendrometric parameters have been evaluated by means of three different inventories: i) 1998 before and after thinning, ii) 2002, iii) 2006. In particular the dynamics of horizontal structure (permanent transects) and the trend of stability indicators (height – diameter ratio, crown depth, crown area, crown diameter – stem diameter ratio) have been investigated. Thinning intensity is strictly related to increasing of the pine forest functionality. In a thirty years old stand in good fertility conditions a “strong thinning” (reduction of about half the number of trees and 35% of basal area) is proved to be effective in increasing stability and stimulating crown growth

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

Early impact of alternative thinning approaches on structure diversity and complexity at stand level in two beech forests in Italy

Stand structure, tree density as well as tree spatial pattern define natural dynamics and competition process. They are therefore parameters used to define any silvicultural management type. This work aims to report first data resulting from a silvicultural experiment in beech forests. The objective of the trial is testing the structure manipulation in terms of diversity and the reduction of inter-tree competition of different thinning approaches. Alternative thinning methods have been applied in two independent experimental sites located in the pre-Alps and Southern Apennines, in Italy. Specific goals were to: (i) verify the impact early after thinning implementation on forest structure through a set of diversity and competition metrics resulting from a literature review; (ii) the sensitivity of tested indexes to effectively detect thinning manipulation. Main result show the low sensitivity of stand structure indexes and the ability of competition metrics to detect thinning outcome

Early impact of alternative thinning approaches on structure diversity and complexity at stand level in two beech forests in Italy

Stand structure, tree density as well as tree spatial pattern define natural dynamics and competition process. They are therefore parameters used to define any silvicultural management type. This work aims to report first data resulting from a silvicultural experiment in beech forests. The objective of the trial is testing the structure manipulation in terms of diversity and the reduction of inter-tree competition of different thinning approaches. Alternative thinning methods have been applied in two independent experimental sites located in the pre-Alps and Southern Apennines, in Italy. Specific goals were to: (i) verify the impact early after thinning implementation on forest structure through a set of diversity and competition metrics resulting from a literature review; (ii) the sensitivity of tested indexes to effectively detect thinning manipulation. Main result show the low sensitivity of stand structure indexes and the ability of competition metrics to detect thinning outcome

Le pinete demaniali costiere di Ravenna e Ferrara: analisi dei tipi forestali e strutturali per la scelta del trattamento selvicolturale nel processo di pianificazione

The state-owned pine forests on the coast of Ravenna and Ferrara: analysis of forest and structure types for choice of silvicultural system in the planning process. Results of the analysis on typology and structure of state forests dominated by maritime pine (Pinus pinaster Ait.) are reported. These formations grow on a narrow coastal belt between Cervia (Ravenna) and Volano (Ferrara), in the Emilia-Romagna region (Italy). The aim of the study is to support the proper silvicultural system in order to satisfy multiple use of pine forests using the analysis of forest types and model types of structure. Main ecological and structural features of principal pine forest types and experimental criteria on silvicultural systems are explained

The Turkey oak high forests in the Molise region (central Italy). Analysis of past silvicultural system and current management choices.

Aim of the work is to provide further knowledge on the silvicultural system applied to Quercus cerris hight forests in the Molise Region (Central Italy). An historical analysis, based on a number of forest management plans applied since 1940 referred to 19 municipalities and on other historical documents, is provided in the paper. Forest management has been traditionally applied in the Molise Region and therefore is at now possible to reconstruct in detail the management of the forests of Molise Region. The historical study has been integrated with the analysis of a chronosequence including four steps of stand development in a Turkey oak stand: the regeneration phase (1-2 yrs) - the unthinned young stand (46 yrs) - the unthinned adult stand (aged 60 to 100) - the mature stand (126 yrs). Mensurational surveys were carried out at each phase in order to characterize both stand structure and derive information on the silvicultural practices applied in the past, but not documented in the available papers. The stand age was determined by tree coring and count of annual rings. At the beginning of the last century, the silvicultural system to be applied in oak high forests wasn’t strictly defined and a particular kind of selection cutting was carried out. It was named taglio a salto per sezioni i.e. “compartment selection cutting”, partly leading back to a real selection cutting, partly to a shelterwood system. The use of the reported silvicultural system gave rise to irregular forest structures and led to management problems well-described in the management plans at the end of 1940s. Another consequence of the applied practices was the absence or the inadequate natural regeneration establishment. The contemporary unregulated practice of grazing the forest floor contributed to the unsuccessful regeneration and made the situation worse. The presence of an understorey layer made up by sproutings from Carpinus betulus stools clearcutting, was a further hindrance to the establishment of natural oak regeneration. In the fifties, the rate of forest management increased as a consequence of the coming up economic concern in sleeper production. The silvicultural shelterwood system was therefore codified. The system resulted to be more effective and adopted up to the present time. The traditional shelterwood system was based on a 90 yrs rotation length, three thinnings performed from the age of 25 up to 75, time of the seed cutting with a release of 90 trees per hectare. In the seventies, following the much more reduced and even null concern in wood production from oak high forests, practices into the same forests were suspended or postponed. At now, the renewed concern for fuelwood production, the only assortment marketable, as well as the increased attention paid to the multifunctional role of these forests, made again actual the problem of oak high forest management. The effectiveness of shelterwood system is the main outcome of the documental analysis performed. The study of the Carovilli’s chronosequence confirmed the close link between the current stand structures and the prescribed rules adopted in the past, in accordance with the management plans. The experimental trials in progress are now focused at defining an improvement of the shelterwood system practice as for the following issues: reduction of cutting areas; establishment of a more complex structural mosaic at neighbouring forest patches, setting up of a consistent release of seed trees i.e. number and dendrotypes to be selected at the purpose, with a special care to the crown cover to the forest floor, effective control of the understorey development due to the resprouting of Carpinus betulus stools, to enhance the establishment of oak natural regeneration