Loading...
Pubblicazioni Scientifiche
Filtri di ricerca 7 risultati
Pubblicazioni per anno
Early impact of alternative thinning approaches on structure diversity and complexity at stand level in two beech forests in Italy
Becagli
,
Claudia
,
Puletti
,
Nicola
,
Chiavetta
,
U.
,
Cantiani
,
Paolo
,
Salvati
,
Luca
,
Fabbio
,
Gianfranco
Mostra abstract
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 detect effectively thinning manipulation. Main results show the low sensitivity of stand structure indexes and the ability of competition metrics to detect thinning outcome.
Allometric relationships for volume and biomass for stone pine (Pinus pinea L.) in Italian coastal stands
Mostra abstract
Tree biomass plays a key role in sustainable forest management and in determining forest carbon stocks. Accurate estimates based on species-specific empirical data are necessary for regional and national inventories and forest carbon management. In this study, we obtained allometric relationships for volume and aboveground biomass for stone pine (Pinus pinea) based on empirical data collected in four coastal stands in Italy. Root sampling was also performed. The results enabled generalized equations for volume and aboveground biomass to be developed. However, an analysis also showed several differences in biomass allocation in stone pine resulting from different stand characteristics, emphasizing the importance of stand-dependent factors for adjusting regional or national biomass calculations. Biomass expansion factors were also provided. This study provides tools to help forest managers in quantifying volume and biomass, thereby contributing to the accurate estimation of carbon sequestration and stocks in stone pine stands in Italy. © SISEF.
Mast seeding in deciduous forests of the northern Apennines (Italy) and its influence on wild boar population dynamics
Cutini
,
Andrea
,
Chianucci
,
Francesco
,
Chirichella
,
Roberta
,
Donaggio
,
Emanuela
,
Mattioli
,
Luca
,
Apollonio
,
Marco
forest management
forest seed production
game management
pulsed resource
silvicultural treatment
sus scrofa l.
Mostra abstract
Context: Pulsed food resources may strongly affect the population dynamics of several consumer species, with consequences on the ecosystem. One of the most common pulsed resources is forest mast seeding. Aims: We analysed mast seeding in deciduous forests in a mountainous area of northern Apennines and its effect on population dynamics of wild boar (Sus scrofa L.). Methods: We performed a quantitative, 20-year analysis on annual seed production in Turkey oak (Quercus cerris L.), beech (Fagus sylvatica L.) and chestnut (Castanea sativa Mill.) forest stands using litter traps. The wild boar population density was estimated by means of drive censuses and hunting bag records. The role of other biotic (density of predators) and abiotic (climate) factors potentially affecting wild boar mortality was also investigated. Results: Turkey oak and chestnut showed high levels of seed production, whereas lower levels were found in beech. The pulsed resources of chestnut and Turkey oak positively affected piglet density. Analyses also highlighted the influence of snow cover and wolves on wild boar population dynamics. Conclusion: Wild boar can be considered a pulse rate species, the management of which can be improved by annual monitoring of seed production. © 2013 INRA and Springer-Verlag France.
Estimation of canopy properties in deciduous forests with digital hemispherical and cover photography
leaf area index
cover photography
digital hemispherical photography
clumping
light extinction coefficient
Mostra abstract
Rapid, reliable and meaningful estimates of forest canopy are essential to the characterization of forest ecosystems. In this paper the accuracy of digital hemispherical (DHP) and cover (DCP) photography for the estimation of canopy properties in deciduous forests was evaluated. Leaf area index (LAI) estimated from both these photographic methods and from light transmittance data derived from DHP were compared with direct measurements obtained by litter traps (LAI<inf>LT</inf>) and an AccuPAR ceptometer. Also, comparison with different gap fraction methods used to calculate LAI in DHP and LAI-2000 PCA were performed.We applied these methods in four forest stands of Quercus cerris, two stands of Castanea sativa and four stands of Fagus sylvatica, the most common deciduous species in Italy, where LAI<inf>LT</inf> ranged from 3.9 to 7.3. Both photographic methods provided good indirect estimates of LAI<inf>LT</inf>. The DCP method provided estimates of crown porosity, crown cover, foliage cover and the clumping index at the zenith, but required assumptions about the light extinction coefficient at the zenith (k), to accurately estimate LAI. Cover photography provided good indirect estimates of LAI assuming a spherical leaf angle distribution, even though k appeared to decrease as LAI increased, thus affecting the accuracy of LAI estimates in DCP. In contrast, the accuracy of LAI estimates in DHP appeared insensitive to LAI<inf>LT</inf> values, but the method was sensitive to photographic exposure and more time-consuming than DCP.The studied stands were characterized by higher within-crown clumping than between-crowns clumping; only the segmented analysis of gap fraction for each ring of the fisheye images was found to provide reliable and useful clumping index in DHP. The 1-azimuth segment method employed in PCA poorly detected clumping in dense canopies.The correlation between transmittance estimates by DHP with values measured at noon with the AccuPAR ceptometer was linear and significant, although the variability observed in reference measures suggested that results obtained with the ceptometer should be treated with caution.We conclude both photographic methods are suitable for dense deciduous forests. Cover photography holds great promise as a means to quickly obtain inexpensive estimates of LAI over large areas. However, in situations where no direct reference measurements of . k are available, we recommend using both DHP and DCP, in order to cross-calibrate the two methods; DCP could then be used for more routinely indirect measurement and monitoring of LAI. © 2012 Elsevier B.V.
Stand structure and ecological changes in holm oak coppices 25 years later the opening of thinning operations for the conversion into high forest; Cambiamenti strutturali ed ecologici in cedui di leccio in Sardegna a 25 anni dal taglio di avviamento ad altofusto
Manetti
,
Maria Chiara
,
Giannini
,
Tessa
,
Chianucci
,
Francesco
,
Casula
,
Antonio
,
Cutini
,
Andrea
Mostra abstract
Holm oak (Quercus ilex L.) is one of the most diffuse and economically important forest species in Sardinia, where it holds about 40% of holm oak cover in Italy. The forest type has also acquired a high ecological, recreational and landscape value over the last decades. Most of holm oak stands originated from overgrown coppice forests partly undergoing conversion into high forest. This study was set up in 1994 to analyse, as a function of site-index, the effects of conversion thinning on productivity, biodiversity, structural dynamics and canopy characteristics in an holm oak forest located in southern Sardinia. Two experimental permanent plots, differing in site index, stand structure and tree density, were established. The surveys were carried out in 1994-95 and 2010-11. The analysis included growth pattern, dynamics of stand structure and estimation of forest canopy attributes as leaf area index and canopy transmittance. Results pointed out the simplified stand structure, the poor biodiversity, the low LAI and high transmittance values 9 years after thinning implementation. These characteristics were more pronounced in the less productive area, characterised by substantial canopy gaps. 25 years after thinning implementation, both stands showed significant increase in the number of trees, strengthening of the clustered structure and high canopy recovery. Conversely, no significant changes in biodiversity and vertical structure were observed. Overall results contributed to a positive evaluation of the conversion practice based on periodical thinnings, even if the excessive reduction of tree density, mainly in the lower site-index area, did not allow yet the fully achievement of canopy recovery.
Multifunctionality assessment in forest planning at Landscape Level. The study case of Matese mountain community (Italy)
Di Salvatore
,
Umberto
,
Ferretti
,
Fabrizio
,
Cantiani
,
Paolo
,
Paletto
,
Alessandro
,
De Meo
,
Isabella
,
Chiavetta
,
U.
forest landscape management planning
forest multifunctionality
function fulfilment index
matese district (italy)
silvicultural system
Mostra abstract
The main objective is to improve a method that aims at evaluating forest multifunctionality from a technical and practical point of view. A methodological approach - based on the index of forest multifunctionality level - is proposed to assess the "fulfilment capability" of a function providing an estimate of performance level of each function in a given forest. This method is aimed at supporting technicians requested to define most suitable management guidelines and silvicultural practices in the framework of a Forest Landscape Management Plan (FLMP). The study area is the Matese district in southern Apennines (Italy), where a landscape planning experimentation was implemented. The approach includes the qualitative and quantitative characterization of selected populations, stratified by forest category by a sampling set of forest inventory plots. A 0.5 ha area around the sample plot was described by filling a form including the following information: site condition, tree species composition, stand origin and structure, silvicultural system, health condition, microhabitats presence. In each sample plot, both the multifunctionality assessment and the estimate of the effect of alternative management options on ecosystem goods and services, were carried out. The introduction of the term "fulfilment capability" and the modification of the concept of priority level - by which the ranking of functions within a plot is evaluated - is an improvement of current analysis method. This enhanced approach allows to detect the current status of forest plot and its potential framed within the whole forest. Assessing functional features of forests with this approach reduces the inherent subjectivity and allows to get useful information on forest multifunctionality to support forest planners in defining management guidelines consistent with current status and potential evolutive pattern.
Application of k-nearest neighbor on multispectral images to estimate forest parameters; Aplicação de k-nearest neighbor em imagens multispectrais para a estimativa de parâmetros florestais
Giongo
,
Marcos Vinicius
,
Chiavetta
,
U.
,
Soares Koehler
,
Henrique Soares
,
Machado
,
S. A.
,
Kirchner
,
Flávio Felipe
Mostra abstract
Natural resources management requires several parameters estimate in order to support the identification of the best alternatives to forest areas management. In particular, forest ecosystems require a complex and increasing set of descriptive information, where forest inventories put up important information, however not in a continuous spatial way. Lately, several scientific researches have been focusing on establishing methodologies to relate data from field to those obtained from multispectral images. Modeling these relations can extend the estimates of forest inventory data to not sampled areas. This research evaluated performance of non-parametric analysis using the K-Nearest Neighbor (k-NN) on SPOT 5 images. It evaluated the results obtained from the spatialization of some forest attributes in a forest area located at Molise, Italy. Among several methodologies for spatial distance calculations, the use of multiregressive non-parametric distances revealed the best results. Density and number of species on the ground revealed a Pearson correlation coefficient of = 0.58 as compared to data obtained from multispectral images, lightly lower than the obtained for basal area and volume, which were = 0.62 and 0.71, respectively.