Fabio Lombardi

Old-growth forest structure and deadwood: Are they indicators of plant species composition? A case study from central Italy

Abstract The aim of this paper is to investigate differences in plant species composition between managed and unmanaged forests, and to assess if these difference give rise to a higher plant diversity in the unmanaged forest. Furthermore our aim is to relate forest structure to differences in plant species composition, identifying the structural attributes more strongly related to the unmanaged forest vegetation. We compared an old-growth forest and a managed highforest in the Abruzzo Lazio and Molise National Park (Central Italy). Plant species composition and diversity, deadwood components and live structure have been analyzed. We used permutational multivariate analysis of variance to test the response of species composition to management factor; furthermore, we compared species richness and beta diversity. Redundancy analysis has been used to relate plant species abundances to structural variables; the importance of dead and living wood components has been compared through variation partitioning. Plant species composition proved to be significantly different in the two sites, and the old-growth stand showed a higher plant diversity. From a structural point of view, we found differences especially in the amount and quality of deadwood, and in the diameter class distribution. These variables are also the most important in determining the old-growth stand plant species composition according to redundancy analysis. Variation partitioning confirmed the greater importance of the deadwood variables. Our results suggest that including deadwood surveys in traditional forest inventories could help in finding forests with both structural and floristic old-growth properties to be considered in conservation programmes. The imitation of natural dynamics, through the creation of gaps avoiding deadwood removal, could be an effective strategy for restoring old-growth conditions, also in terms of plant diversity.

Ecological portrayal of old‐growth forests and persistent woodlands in the Cilento and Vallo di Diano National Park (southern Italy)

Abstract The maintenance of certain levels of old forest represents a cornerstone of the EU’s biodiversity management strategy. A consensus on a single general ecological definition of old‐growth is particularly difficult in Mediterranean Europe. The present paper deals with old‐growth forests and persistent woodlands in the Cilento and Vallo di Diano National Park (PNCVD) to give an ecological understanding of forest complexity and dynamics under a multiscale and multidisciplinary perspective. The multiscale approach ranged from the identification and mapping of potential old‐growth stands at landscape scale to a two‐level field review of forest stand features. Field sampling involved a multidisciplinary team of researchers in forest structure, pedologic environment, soil microbial activity, flora and vegetation and deadwood components. The research provided sound knowledge about old‐growthness features in the PNCVD that constitutes a unique case study in the whole Mediterranean basin. The integration of results allowed to: identify main ecosystem functions and the related services of the old‐growth forests in the study area; distinguish persistent woodlands, multi‐aged stands with old trees deriving from nineteenth‐century management practices, from old‐growth forests sensu strictu; recognize indicators of direct and indirect impacts of human activities; suggest effective practices for sustainable management in the Mediterranean context.

Deadwood in Relation to Stand Management and Forest Type in Central Apennines (Molise, Italy)

Deadwood is an important component for conserving carbon stock and maintaining species diversity. Scarce information is, at present, available concerning the amount and composition of deadwood in Mediterranean-type ecosystems. In this study, 21 sites were chosen to characterize different forest types among representative managed and unmanaged stands in the Central Apennines (Molise, Italy). Data were collected to assess living tree and deadwood volumes, and the relative abundance of different deadwood components in decay classes. The information gathered was related to human-induced disturbances on a regional scale. There were substantial differences in the deadwood volumes between managed and unmanaged stands, although this was not the case in the living tree volumes. Deadwood volumes were larger in unmanaged than in managed stands. In particular, large amounts of deadwood were found in managed Mediterranean and Anatolian fir forests, probably due to minimal management practices. Dead downed trees were less represented in managed forests as they are normally removed to facilitate logging activities. Logs occurred more frequently in managed stands as logging residues left on site. Most deadwood material belonged to early decay classes. Proportionally larger amounts of deadwood ascribed to class 1 in managed stands correlated with recent cutting activities. The relatively large amounts of deadwood attributed in unmanaged stands to class 3 demonstrate its longer persistence in unmanaged forests. This study represents a first systematic analysis of deadwood occurrence in a typical Mediterranean forest area, and should be useful in defining important objectives for sustainable forest management.

Modeling the influence of alternative forest management scenarios on wood production and carbon storage: A case study in the Mediterranean region.

Forest ecosystems are fundamental for the terrestrial biosphere as they deliver multiple essential ecosystem services (ES). In environmental management, understanding ES distribution and interactions and assessing the economic value of forest ES represent future challenges. In this study, we developed a spatially explicit method based on a multi-scale approach (MiMoSe-Multiscale Mapping of ecoSystem services) to assess the current and future potential of a given forest area to provide ES. To do this we modified and improved the InVEST model in order to adapt input data and simulations to the context of Mediterranean forest ecosystems. Specifically, we integrated a GIS-based model, scenario model, and economic valuation to investigate two ES (wood production and carbon sequestration) and their trade-offs in a test area located in Molise region (Central Italy). Spatial information and trade-off analyses were used to assess the influence of alternative forest management scenarios on investigated services. Scenario A was designed to describe the current Business as Usual approach. Two alternative scenarios were designed to describe management approaches oriented towards nature protection (scenario B) or wood production (scenario C) and compared to scenario A. Management scenarios were simulated at the scale of forest management units over a 20-year time period. Our results show that forest management influenced ES provision and associated benefits at the regional scale. In the test area, the Total Ecosystem Services Value of the investigated ES increases 85% in scenario B and decreases 82% in scenario C, when compared to scenario A. Our study contributes to the ongoing debate about trade-offs and synergies between carbon sequestration and wood production benefits associated with socio-ecological systems. The MiMoSe approach can be replicated in other contexts with similar characteristics, thus providing a useful basis for the projection of benefits from forest ecosystems over the future.

Investigating biochemical processes to assess deadwood decay of beech and silver fir in Mediterranean mountain forests

ContextWe investigated the relationships between decay classes, morphological characteristics and chemical compounds in Abies alba Mill. and Fagus sylvatica L. stumps in two forest stands in the central Apennines (Italy). The analysis of deadwood decomposition is important in estimating carbon sequestration potential and carbon residence time in forest ecosystems. In addition, deadwood decomposition affects nutrient cycling and microhabitat distribution.AimsThe overall aim of this study was to investigate the decomposition processes in a mountainous Mediterranean ecosystem, and specifically to assess changes in chemical variables (lignin, cellulose, carbon and nitrogen content) in deadwood during the decomposition process, in relation to decay classes and to the species.MethodsCross-sections were collected from stumps. Samples were assigned to visually discernible decay classes, and cellulose, lignin and carbon (C) and nitrogen (N) content in relation to total dry mass were analysed during the decay process.ResultsResults showed how C/N ratio decreased over decades due to an increase in nitrogen content. On the contrary, carbon concentration in stumps remained substantially stable. Lignin degraded slowly in comparison with cellulose and differences between species were observed.ConclusionThe hypothesis that the conifer species would decompose faster than deciduous species did not prove correct. The slower decay of lignin compared to cellulose suggested that lignin could be an important long-term source of soil organic carbon, and that this process could be greatly affected by forest species mixtures. Finally, decomposition processes in the investigated montane–Mediterranean forests were definitely faster than in the colder climates of northern Europe.

ForestBIOTA data on deadwood monitoring in Europe

Abstract Deadwood is a key ecological factor in forest ecosystems. Its occurrence is fundamental since it represents a microhabitat for hundreds of species of invertebrates, fungi, bryophytes, lichens, amphibians, small mammals and birds. In recent years, deadwood has been recognized as a relevant indicator for the assessment and monitoring of forest biodiversity. In this paper the methodology for surveying woody necromass proposed by the ForestBIOTA project under Regulation (EC) No 2152/2003 (Forest Focus) is described. The amount of deadwood found on 91 Intensive Monitoring Level II plot of the EU and ICP Forest condition monitoring programme range from 0 to 258 m3 ha−1. In the examined areas, total deadwood volume does not differ significantly among forest types, due to the high intra-type variability. On the other hand, its distribution between coarse and fine necromass and among necromass components is highly dependent on forest types.

Tree-ring stable isotopes reveal twentieth-century increases in water-use efficiency of Fagus sylvatica and Nothofagus spp. in Italian and Chilean mountains.

Changes in intrinsic water use efficiency (iWUE) were investigated in Fagus sylvatica and Nothofagus spp. over the last century. We combined dendrochronological methods with dual-isotope analysis to investigate whether atmospheric changes enhanced iWUE of Fagus and Nothofagus and tree growth (basal area increment, BAI) along latitudinal gradients in Italy and Chile. Post-maturation phases of the trees presented different patterns in δ13C, Δ13C, δ18O, Ci (internal CO2 concentration), iWUE, and BAI. A continuous enhancement in isotope-derived iWUE was observed throughout the twentieth century, which was common to all sites and related to changes in Ca (ambient CO2 concentration) and secondarily to increases in temperature. In contrast to other studies, we observed a general increasing trend of BAI, with the exception of F. sylvatica in Aspromonte. Both iWUE and BAI were uncoupled with the estimated drought index, which is in agreement with the absence of enduring decline in tree growth. In general, δ13C and δ18O showed a weak relationship, suggesting the major influence of photosynthetic rate on Ci and δ13C, and the minor contribution of the regulation of stomatal conductance to iWUE. The substantial warming observed during the twentieth century did not result in a clear pattern of increased drought stress along these latitudinal transects, because of the variability in temporal trends of precipitation and in specific responses of populations.

ANALISI QUALI-QUANTITATIVA DEL LEGNO MORTO IN SOPRASSUOLI NON GESTITI: IL CASO DI «BOSCO PENNATARO», ALTO MOLISE ( 1 )

La salvaguardia delle foreste ha un punto focale nell’applicazione della selvicoltura sistemica e nella conservazione della biodiversita. Il legno morto viene espressamente citato e politicamente riconosciuto nella MCPFE tra gli indicatori adottati per la Gestione Forestale Sostenibile ed e un importante strumento per valutare e monitorare la biodiversita. Tra i parametri utili alla definizione della vetusta di un popolamento forestale, ci si interroga sul ruolo che puo assumere il legno morto nell’individuazione del grado di vetusta, considerata l’assenza in letteratura di una chiara ed univoca definizione di foresta vetusta per l’elevata diversita riscontrabile sia tra aree geografiche differenti che nell’ambito di una medesima area. Si riporta un caso studio connesso alla realizzazione del Piano di Gestione del «Bosco Pennataro», area forestale montana di elevato valore naturalistico localizzata in Molise, gia interessante per la definizione dei rapporti tra Quercetalia pubescentis e Fagetalia sylvaticae. Il legno morto e stato valutato quali-quantitativamente in aree rappresentative delle tipologie forestali piu diffuse: Cerreta mesofila e Faggeta bassomontana su calcari, associando i risultati ottenuti a considerazioni sull’eventuale presenza di soprassuoli vetusti nell’area in questione. E emerso come il legno morto possa essere un ottimo indicatore del grado di vetusta di un popolamento forestale, ma anche uno strumento per comprendere la fase evolutiva in cui si trova, rendendo visibili ed interpretabili le caratteristiche ecologico-funzionali possedute in passato e la loro evoluzione nel tempo. Il «Bosco Pennataro», pur non essendo considerabile un’area caratterizzata da una vetusta tipica, specialmente se raffrontato ad altre realta forestali non solo nazionali, presenta situazioni locali di interessante valore in relazione alle dinamiche evolutive naturali ed e evidente come l’area sia candidata ad evolvere verso la vetusta in tempi ragionevoli.

Synchronisms and correlations of spring phenology between apical and lateral meristems in two boreal conifers

Phenological synchronisms between apical and lateral meristems could clarify some aspects related to the physiological relationships among the different organs of trees. This study correlated the phenological phases of bud development and xylem differentiation during spring 2010-14 in balsam fir (Abies balsamea Mill.) and black spruce [(Picea mariana Mill. (BSP)] of the Monts-Valin National Park (Quebec, Canada) by testing the hypothesis that bud development occurs after the reactivation of xylem growth. From May to September, we conducted weekly monitoring of xylem differentiation using microcores and bud development with direct observations on terminal branches. Synchronism between the beginning of bud development and xylem differentiation was found in both species with significant correlations between the phases of bud and xylem phenology. Degree-day sum was more appropriate in assessing the date of bud growth resumption, while thermal thresholds were more suitable for cambium phenology. Our results provide new knowledge on the dynamics of spring phenology and novel information on the synchronisms between two meristems in coniferous trees. The study demonstrates the importance of precisely defining the phases of bud development in order to correctly analyse the relationships with xylem phenology.

Soil attributes and microclimate are important drivers of initial deadwood decay in sub-alpine Norway spruce forests.

Deadwood is known to significantly contribute to global terrestrial carbon stocks and carbon cycling, but its decay dynamics are still not thoroughly understood. Although the chemistry of deadwood has been studied as a function of decay stage in temperate to subalpine environments, it has generally not been related to time. We therefore studied the decay (mass of deadwood, cellulose and lignin) of equal-sized blocks of Picea abies wood in soil-mesocosms over two years in the Italian Alps. The 8 sites selected were along an altitudinal sequence, reflecting different climate zones. In addition, the effect of exposure (north- and south-facing slopes) was taken into account. The decay dynamics of the mass of deadwood, cellulose and lignin were related to soil parameters (pH, soil texture, moisture, temperature) and climatic data. The decay rate constants of Picea abies deadwood were low (on average between 0.039 and 0.040y(-1)) and of lignin close to zero (or not detectable), while cellulose reacted much faster with average decay rate constants between 0.110 and 0.117y(-1). Our field experiments showed that local scale factors, such as soil parameters and topographic properties, influenced the decay process: higher soil moisture and clay content along with a lower pH seemed to accelerate wood decay. Interestingly, air temperature negatively correlated with decay rates or positively with the amount of wood components on south-facing sites. It exerted its influence rather on moisture availability, i.e. the lower the temperature the higher the moisture availability. Topographic features were also relevant with generally slower decay processes on south-facing sites than on north-facing sites owing to the drier conditions, the higher pH and the lower weathering state of the soils (less clay minerals). This study highlights the importance of a multifactorial consideration of edaphic parameters to unravel the complex dynamics of initial wood decay.