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Old-growth forest in Italy: Recent research developments and future perspectives
Abstract
In Italy there are no truly primeval forests because forest exploitation has been very pervasive since Roman times. All along the centuries intensive silvicultural systems have heavily modified forest composition and structure. Nevertheless, in particular situations there are forest stands that have not been impacted by utilization for very long periods of time and show old-growth characters. The contribution recall the main projects dealing on characterization and monitoring of old-growth forests in Italy starting from the activities of Prof. Pavari in 1954. It then introduces the papers presented in this special issue resulting from the activities of different recent research projects funded by national authorities. Most of these contributions were presented in a national congress held in Prati di Tivo (TE) from 25 to 26 of June 2010 titled “Old-growth forests in Italy: identification, characterization, management”, organized with the support of the Gran Sasso and Monti della Laga National Park
... However, such pattern did not lead to a parallel development of mature, complex, resilient and biologically rich forest stands (Sferlazza et al. 2017). Nevertheless, some isolated forest stands, left unmanaged for a long time and/or no more subject to relevant forms of human disturbance, tended to recover structural and functional features resembling those of the primary forests; such stands may be termed, under certain conditions, old-growth (Hilbert & Wiensczyk 2007;Chirici & Nocentini 2010). In the last decades, research efforts have been increasingly dedicated to the definition, detection and characterization of old-growth forests (OGFs) in Europe and elsewhere (Keenan & Ryan 2004), due to their widely recognized role in the conservation of biological diversity, the storage of atmospheric carbon and the preservation of natural landscapes (Luyssaert et al. 2008). ...
... Living organisms with limited dispersal ability, which need sufficient ecological continuity, i.e. long time under steady ecological conditions and low disturbance, may be used as reliable proxy bioindicators of old growth forest systems (Nord en & Appelqvist 2001;Blasi et al. 2010). In Italy, although the intensive exploitation of forest resources dates back at least to Roman times (Chirici & Nocentini 2010), it is estimated that old growth forests cover about 160.000 ha. They account for 1.6% of the national forest cover , and are mainly localized in less accessible contexts and steep slopes and/or in areas subject to a special protection regime (Motta 2002;Barbati et al. 2012). ...
Old growth forests are increasingly considered and studied all around the world. However, the knowledge of such important forest systems is still limited in some bioclimatic regions, such as in the Mediterranean Basin. Starting from the knowledge acquired elsewhere, our research was carried out with the aim to select the most effective criteria to identify potential old-growth forests in Mediterranean ecosystems (Sicily, Italy). Four key proxy indicators were considered: deadwood amount, tree size, structural traits, and tree species richness. A preliminary classification of the local forest stands level in three classes of old-growthness (high, medium and low) has also been proposed. The main threats to woods conservation, as well as their biological value were considered. Twenty-one forest stands have been detected and characterized; among them, seven forest stands were close to old growth conditions. Although the selected forest stands are located in protected areas, browsing due to farming and feral ungulates represent a widespread threat. The information provided for each forest stand may represent a starting point for further and in-depth investigations in similar Mediterranean forest ecosystems.
... This is particularly the case in the Mediterranean basin, in which the joint effects of ancient and significant human activities and climatic constraints have caused the widespread presence of semi-open to open ecological systems, with too-short disturbance return intervals to allow the development of mature forest [10][11][12][13]. Nevertheless, in this area, several isolated woodland patches have been recognized that present features of old-growth forest [3,10,[14][15][16]. ...
Old-growth forests are of high interest for biodiversity conservation, especially in the disturbance-prone Mediterranean landscapes. However, it remains unclear whether the survival of patches of old-growth forest in the degraded Mediterranean landscapes results from local anomalies or from past, larger forests. Therefore, in this study, we assessed (1) the origin, (2) the long-term ecological trajectory, and (3) the mechanism(s) that explain the survival of a Mediterranean old-growth forest, the Sainte-Baume forest. To achieve this, we used soil charcoal analysis. We opened fifteen soil profiles in the forest and five in its surrounding areas for soil description and sampling. The soil descriptions enabled us to highlight in situ soil horizon and colluvial layers. A total of 1656 charcoal pieces from different soil samples were taxonomically identified to characterize the composition of past forests. Selected charcoal pieces (n = 34) were dated to obtain chronological data. Our investigations indicate that the survival of the Mediterranean old-growth forest, in the context of the semi-open/open Mediterranean landscapes, is the result of a combination of biotic and abiotic factors, which reduced the influence of past forest disturbances. Thus, the resistance and resilience of the forest areas are preserved over a long-term ecological trajectory. Therefore, the potential of Mediterranean old-growth forests as baseline reference points for the conservation of biodiversity is related to the identification and maintenance of the local biotic and abiotic factors which allowed the survival of the old-growth forest.
... Naturally regenerated forests of native species, where there are no clearly visible signs of human activities and ecological processes are not significantly disturbed, are generally called primary forests (FAO 2015). These often isolated primary forest stands recover compositional, structural and functional features and can be also defined old-growth forests or long untouched forests (Buchwald 2005, Chirici & Nocentini 2013. As a forest ages, peculiar structural features develop, for instance through the accumulation of high quantities of large trees and deadwood, which determines an increase in general complexity (=heterogeneity) of the forest structure (Burrasacano et al. 2018). ...
Mediterranean forests have been altered by several human activities. Consequently, relatively intact forests that have been unmodified by humans for a relatively long time (i.e., old-growth forests) are often reduced to isolated and fragmented stands. However, despite their high conservation value, little is known about their features and even presence several Mediterranean areas. First steps of their investigation are based on the identification of old-growth features such as amount of large‐size and old trees, tree species composition, canopy heterogeneity, occurrence and amount of deadwood. The Structural Heterogeneity Index (SHI) is commonly used to summarise features of old-growthness in one single value. Here, the SHI was derived for 68 plots included in 45 forest stands within the 4,297 km2 of territory that is covered by forests in Sardinia. SHI values were affected by variables that are likely to be related to forest age and structural complexity, such as presence of cerambycids, canopy cover, forest layers, location and three old-growthness classes. Results confirm a high structural variability among forests with old-growth features, determined by the presence, or lack, of given living and deadwood features. Our findings identified, for the first time, most of the forest stands that need special protection in Sardinia for the presence of old-growth features. In this sense, the SHI was confirmed useful for improving their management and conservation, although more specific and deeper studies are necessary for better understanding their species composition and dynamics.
... Land abandonment and decrease of forest harvesting has also raised the interest for forests with old-growth characteristics (Marchetti and Blasi, 2010;Chirici and Nocentini, 2013). These stands, prevalently dominated by beech, house some of the tallest and oldest trees in Europe; they have a significantly higher deadwood volume than ordinarily managed forests with similar composition (Lombardi et al., 2013), and a living biomass comparable or higher than central European old-growth forests, in both pure beech (302-1383 m 3 ha À1 ) and mixed beech-fir stands (570-1189) (Calamini et al., 2011). ...
... Paci & Salbitano 1998;Motta 2002;Piovesan et al. 2005). The interest on old-growth forest studies has been recently renewed by national projects aimed to increase the knowledge on old-growth forest stands in the Alps and Apennines (Blasi 2010;Chirici & Nocentini 2010;Piovesan et al. 2010). In these projects, the following topics were addressed: ecology ) and stand structure (Ciancio et al. 2010;Iovino et al. 2010;Manes et al. 2010;Palombo et al. 2010;Piovesan et al. 2010), deadwood (Burrascano et al. 2008;Lombardi et al. 2010;Motta et al. 2010), vascular flora (Sabatini et al. 2010), lichens and bryophytes (Brunialti et al. 2010;Potenza & Fascetti 2010;Ravera et al. 2010), carbon stock (Piovesan et al. 2010), genetic diversity (Vettori et al. 2010), monitoring systems Corona et al. 2010;Di Paolo et al. 2010) and, finally, possible indications from old-growth studies in supporting forest management and planning in areas with long standing human impact (Nocentini 2010). ...
An old-growth beech forest stand with silver fir within the strict forest reserve of Sasso Fratino has been examined with the following aims: to characterize forest stand on the basis of classic forest parameters and to assess forest stand structure by means of spatial functions; to provide genetic dating of the beech population. Total census of size and position of living trees and deadwood was performed on a 9200 m permanent plot. Vertical distribution of crowns in the stand was assessed using the TSTRAT function, horizontal stand structure using spatial point pattern analysis. Genetic dating was performed on a sample of beech trees. DNA was isolated and each individual was genotyped at four chloroplast microsatellite loci. Microsatellite profiles were compared with the profiles of control DNA of known haplotypes. Results show a multi-strata vertical structure, a horizontal structure characterized by small gaps (
... Recent reviews on this subject (Chirici and Nocentini 2010) show that several authors have identified and studied what have been defined as OGFs in Italy. These OGFs are mainly located in mountain areas in the Alpine (Motta 2002; Motta et al. 2006; Motta and Edouard 2005) and Apennine regions (Paci 1998; Piovesan et al. 2005; Burrascano et al. 2009). ...
The concept of the old-growth forest is highly debated in the literature because of its implications, from close-to-nature forest management to carbon balance. Studies on old-growth forests have multiplied in the last three decades. Most of these studies have focussed on defining the structural features of old-growth forests of non-Mediterranean forest ecosystems or of specific forest types. In Italy, forest structure since Roman times has been greatly influenced by man. For this reason, the concept of old-growth forest in these ecosystems seems more controversial than at the global level. Nonetheless, in the Mediterranean region, there are persistent forest formations that present a certain level of oldgrowthness. These types of forests have been identified mostly in National Parks. The description of forest structure requires a vast amount of information about several biometric attributes. Consequently, the classification of forests as old growth is very time- and resource-consuming. This research aims to describe and test a proposed methodology to classify and determine the relative oldgrowthness of a series of forest inventory plots. Data from 77 beech forest plots located all across Italy were collected and compared with a virtual reference plot. To compare the forest plots, a set of similarity/dissimilarity indexes were tested. The results obtained show that it is possible to accurately rank the oldgrowthness of forest plots and to screen them to exclude non-old-growth forests. The method described was applied for the first time on a set of plots located in the Italian National Parks to determine a priority list of beech forests where further studies need to be conducted.
Old growth forests, i.e. forests which have achieved a remarkable age without or with a very lim-ited disturbance, are nowadays subject of detailed studies in order to understand their characters and capacity of ecosystems services providing. In Sicily only few wooded areas are classified as old growth forest, following the heavy land use change toward agriculture during the centuries. This paper reports the results of a study carried out to characterize the vegetation of a little crater on the Mount Etna, where a residual open wood of Quercus congesta (an endemic oak of Southern Italy) survived the year 1651 lava flows surrounding the crater. About 35 years ago inside the crater some areas were planted with Calabrian Black Pine. As a consequence today there is a remarkable com-petition between trees of the two species. An integrated approach monitoring was adopted, tak-ing into account both trees and understory (herbs, shrubs and tree regeneration) characters as well as bird fauna, in order to describe the current situation and monitor the effect of pine plantation thinning aimed at favouring oak regeneration and reducing pine-oak competition.
La virtual ausencia de bosques maduros y la extrema escasez de rodales en estado de senescencia en España, hace oportuno el desarrollar metodologías para su identificación y criterios de gestión que permitan su adecuada conservación.
Constituyen los hábitats forestales de mayor naturalidad disponibles, y por tanto, son un valioso referente tanto para el análisis del estado de conservación de los hábitats arbolados, como para su gestión.
Old-growth forests are characterized by the presence of large and very large trees. The estimation of their wood volume and biomass is essential in order to monitor the ecological processes in these stands and their contribution to carbon cycle. However, conventional wood volume estimation techniques based on mensuration of stem diameter at breast height and tree height is most often unfeasible for large and very large trees in old-growth forests because volume models or tables are usually elaborated from trees of smaller size grown up in regularly managed forest stands. Random Branch Sampling (RBS) is often proposed as a possible estimation alternative under such conditions. Starting from the ground level some of the parts of the main trunk and of the branches are sampled and measured to estimate the overall wood volume (or other biophysical variables). The application of RBS in old-growth forests, where tree cutting is usually forbidden or very difficult, requires that the crown of the tree can physically be reached to measure the sampled parts. We argue that under such conditions it is usually preferable to fully measure all the components of the tree crown because RBS estimates are not precise if based on only one sampling path and that, on the other hand, measuring the main trunk and all the branches by tree-climbing consumes the same time as replicating several RBS paths on the same tree. To demonstrate our hypothesis we selected 16 large beech trees located in the old-growth forest of Mount Cimini in Central Italy. Using a modern tree-climbing approach the main trunk and all the branches were measured and recorded in the field. The database was used to simulate RBS paths. Real values from volume census were contrasted with estimates based on RBS. On the whole, RBS estimates based on one single path prove to be highly imprecise. Even for trees characterized by a rather regular form, at least three RBS paths should be repeated on the same tree to maintain the relative standard error under or near 15%. This paper introduces the problem and describes the experimental test. The results are discussed under the perspective of standardized application of the proposed methodology.
The study has been carried-out to compare the genetic diversity between old-growth beech forest and post-harvested naturally regenerated stands. The purpose was also the evaluation of the possible genetic impact of harvesting systems; these information are needed for the development sustainable silvicultural methods.
The paper discusses if and how research results can support forest management and planning in areas where forests have been heavily and pervasively modified during the
centuries. Along with the rare tracts of old-growth forests, the reduction in forest utilization which has taken place in Italy starting from the 1960’s has favored natural development and
an increasing degree of “old-growthness” in many once managed forest stands.
Difficulties in using “old-growth” forests as models for sustainable forest management in this situation arise from many factors: scarcity and limited surface of most old-growth
forests; relatively short history of non-management; heavily disturbed surrounding matrix.
Further uncertainty is added by the fact that old-growth forests have developed in climatic and environmental conditions which might be very different from the ones that will be faced in the future.
Nevertheless lessons can be learned if the growing scientific knowledge is connected to a dynamic concept of forest ecosystems and forest management, where monitoring and
feedback is the basis for adapting silviculture to the reactions of each different stand. In areas with long standing human impact, interdisciplinary research insights into the structural
changes and development processes of forests which have been subtracted from direct management and utilization, can provide criteria and indicators for designing monitoring
schemes in support of forest management, and for implementing ecological networks which integrate biodiversity conservation with socio-economic opportunities and constraints.
1) Calabrian pine forests are the peculiar feature of the landscape of many Italian mountain areas: Etna, Aspromonte and, especially, Sila. Sila landscape conservation is important not only for cultural and historical heritage value, but also for environmental and socioeconomic aspects. This is particularly relevant as most Calabrian pine forests are now included in the Sila National Park. The authors analyze the structure of an old growth pine forest. The main structural characters are compared with those of small group selection pine forests. Results show that small group selection felling, a tradidional silvicultural system peculiar to this area for Calabrian pine, is the best silvicultural approach for the conservation of Calabrian pine forests.
Vascular plants understorey of an old-growth beech forest was compared to a managed stand, similar for biogeographical, climatic and abiotic features. Parametric tests and accumulation and rarefaction curves were used to compare the stands in terms of vascular plant diversity at stand level and among sampling units. The sampled understorey species were characterized in terms of functional traits and Ellenberg's indicator values; next, we calculated four different pairwise plot-to-plot dissimilarity matrices based on: 1. species presence/absence, 2. cover values, 3. functional traits and 4. Ellenberg's indices. We applied a permutational multivariate extension of ANOVA to test whether the forest stands significantly differ in the considered features. Furthermore we used fourth corner analysis to highlight which single functional trait is significantly associated to each stand. Although not richer at plot level the old-growth stand resulted more diverse both at stand level and in terms of among-plots diversity than the managed one. All the comparisons performed through permutational multivariate ANOVA showed significant differences, with the exception of the one based on Ellenberg's indices. From a functional and ecological perspective in the old-growth forest we noted: 1. a relative increase of hemicryptophyte species with limited dispersal abilities (ant-dispersed or non specialized); 2. a decrease in early-flowering geophytes; 3. a parallel increment in small seeded, wind-dispersed species adapted to relatively open and bright conditions (gaps). Our results suggest that in the old-growth stand the high vertical and horizontal structural heterogeneity of the canopy modulates the ecological conditions at the forest floor and increases the environmental heterogeneity. This mechanism is likely to allow the coexistence of a higher number of species, with different ecological requirements.
In the Mediterranean basin human activity has modified landscapes for millennia, nevertheless there are few remote forest areas relatively untouched long enough from direct anthropogenic disturbance to develop old-growth attributes. The aim of this note is to assess the potential of QuickBird (QB) satellite multispectral imagery for detecting old-growth forest stands, considering as case study a Mediterranean beech forest in central Italy. The segmentation-based analysis of QB image proved to be a promising tool to detect scaledependent pattern of forest structural heterogeneity. Values of remotely sensed attributes are compared in old-growth and not-old-growth stands: the statistical analysis showed that oldgrowthness is associated to the variability of multispectral reflectance from the image objects (polygons). Green band variability, notably, expressed by Ratio_band_2 has proven to be helpful for predicting old-growthness.
This study was carried out in the “La Verna” forest, located in the “Foreste Casentinesi, Monte Falterona, Campigna” National Park at the border between Arno and Tevere watersheds. The forest covers an area of 203 ha and it is owned by the Franciscan religious order. Since 1985 the “La Verna” forest has been managed by the “Casentino” Comunità montana.
In 2008 a sector of about 36 ha was selected for an intensive study of the stand structure, and the quality and quantity of coarse woody debris (CWD). A regular network of 33 sampling point was established.
The average stem density was 473 trees ha-1 (range 133-1283) and the growing stock of living trees was 657.1 m3ha-1 (299-1452.9). The average volume of CWD was 66.9 m3ha-1 ranging between 3.7 and 355.8 m3ha-1. Of the total volume of dead and living trees, CWD comprised 10.2%. Among the CWD the volume of logs (66.1%) was greater than the volume of snags (28.3%) and stumps (5.6%).
The study has emphasized that the “La Verna” forest, besides the historical and cultural value, has an important naturalistic value. The past low-intensity silviculture, traditionally applied by the Franciscan monks, has allowed the development of the current mixed structure and the co-existence in a managed forest of some structural “old-growth” characteristics e.g. the multi-layered vertical structure, the high living biomass and the
quantity and quality of CWD.
All forests in the Italian Alps have been affected by humans in some way, either through direct periodic destruction of the forest or by more subtle forms of management and habitat manipulation. For this reason it is very difficult to find stands with old-growth properties°d. However, in the last century there has been a noticeable reduction in many human activities in the mountains and, as a result, many forest stands have developed naturally over the past few decades, even if their composition and structure still reflect past human activity. This makes it particularly important to study the unmanaged parts of previously managed forests: the past history, present structures and long-term monitoring of these forest stands are fundamental steps for increasing our knowledge of the natural forest stand dynamics. Knowledge of this sort is an important reference tool for the present and future development of near-natural silviculture aimed at producing commodities as well as maintaining environmental values. In this paper, a case study in the forest of Paneveggio is presented. In this forest, a strict forest reserve of about 100 ha was established, and a long-term forest dynamics study was set up in four 1-ha plots. The main results of the study of the stand histories of these plots are presented, and their current naturalness status is discussed.
In the European Alps, ancient protective forests have represented important landscape and cultural features for centuries. At the present time they often host interesting
plant communities with varied structures and extreme age not far from those observed at the upper tree-line or in inaccessible sites. This is primarily a result of past management that
precariously balanced the forest’s strong protective properties and its resources. Therefore, ancient protective forests represent very interesting research topics, especially if they show unevenly-aged structures, century-old stand continuity and singular historic or naturalistic features. The present study aims to reconstruct past disturbances and the age structure of an ancient coniferous forest located on the southern slopes of the Swiss Alps (Canton Ticino, Switzerland), by means of historical and dendroecological data. Results show that during
the last three centuries of human activity (especially logging but also traditional non-timber forest use) has had a considerable impact on the study area. In contrast, exogenous
disturbances (natural events) are supposed to have influenced forest structure more on a local scale. Endogenous dynamics appear to be fairly significant, especially after a decrease
in human activity and the abandonment of traditional forest practices. The timing and intensity of disturbances coincide reasonably well with potential anthropogenic causal
factors. Knowledge of local forest dynamics and past disturbance regimes could help forest managers to better understand changes and, at the same time, help historians to analyse the impact of driving forces and single events on past landscapes.
Question: Which are the structural attributes and the history of old-growth Fagus forest in Mediterranean montane environments? What are the processes underlying their structural organization? Are these forests stable in time and how does spatial scale affect our assessment of stability? How do these forests compare to other temperate deciduous old-growth forests?
Location: 1600–1850 m a.s.l., Fagus forest near the tree line, central Apennines, Italy.
Methods: An old-growth Fagus forest was studied following historical, structural and dendroecological approaches. History of forest cover changes was analysed using aerial photographs taken in 1945, 1954, 1985 and 1994. The structural analysis was carried out in the primary old-growth portion of the forest using 18 circular and two rectangular plots. Dendroecological analyses were conducted on 32 dominant or co-dominant trees.
Results: These primary old-growth Fagus remnants consist of four patches that escaped logging after World War II. Both living and dead tree components are within the range of structural attributes recognized for old-growth in temperate biomes. Dendroecological analyses revealed the roles of disturbance, competition and climate in structuring the forest. We also identified a persistent Fagus community in which gap-phase regeneration has led to a mono-specific multi-aged stand at spatial scales of a few hectares, characterized by a rotated-sigmoid diameter distribution.
Conclusion: Even at the relatively small spatial scale of this study, high-elevation Apennine Fagus forests can maintain structural characteristics consistent with those of old-growth temperate forests. These results are important for managing old-growth forests in the Mediterranean montane biome.