Biology subjects

Marano, G.

Publications and source records attributed to Marano, G..

6 recordsLinked to original sources

bioRxiv2025

Predicting drought-induced tree mortality in Swiss beech forests hinges upon predisposing and inciting factors

The increase in the frequency and severity of drought-induced tree mortality in many European low-elevation forests poses considerable challenges to forest management and requires an understanding of its causes. We propose a novel framework for integrating the factors underlying drought-induced tree mortality in a dynamic vegetation model. We evaluate whether this framework accurately reproduces drought-related mortality in six mesic beech-dominated stands in 2018-2020, and over multiple years in a xeric Scots pine-dominated stand in Switzerland. Additionally, we investigate its behavior along a large climatic gradient in central Europe. We employ a three-step approach. First, we evaluate multiple drought indices for capturing tree growth responses to extreme drought. We find that in contrast to widespread indices such as SPI and SPEI, the ForClim drought index captures growth responses to drought intensity during summer, the growing period, and annually. Second, we assess in detail the capability of the ForClim soil moisture model to simulate soil water dynamics, comparing it to the mechanistic soil-vegetation-atmosphere model LWFBrook90. The ForClim soil moisture model adequately simulates soil water dynamics, particularly in extreme drought years. Third, based on Manions Decline Disease Theory, we develop a novel mortality sub-model that combines predisposing and inciting factors. Its integration in ForClim captures drought-induced mortality events in the mesic beech forests as well as the multi-year mortality at the xeric Scots pine-dominated stand. Along a climatic gradient in central Europe, the model provides good quantifications of Potential Natural Vegetation. The novel framework to capture drought-related tree mortality is simple yet produces accurate results. The underlying hypothesis regarding the factors leading to drought-induced tree mortality is promising but requires further tests for its generality.

ecology↗

bioRxiv2025

Long-term forest-sector mitigation and radiative forcing under contrasting management, climate, and substitution pathways

Forests are central to the EUs climate neutrality strategy, currently offsetting [~]9% of total greenhouse gas emissions and offering further mitigation potential through harvested wood products and the substitution effect. However, the climate benefit of the forest sector is influenced by multiple interacting factors, including forest management, climate change, wood-use strategies, and assumptions about substitution benefits, as well as the timing and fate of carbon across the forest ecosystem and technosphere. To evaluate these drivers, we used a coupled forest growth and a wood products model to simulate five different silvicultural strategies under three climate change scenarios, four wood use schemes, and five displacement factor decay pathways over a 285-year period (2015-2300), applied to a Pinus nigra forest in Italy, questioning the impact of these factors on climate mitigation potential of the forest sector. We assessed forest sector balance (FSB, net carbon exchange between forest system and atmosphere), radiative forcing from biogenic CO2 (RFbio), and mitigation efficiency (ME) - the proportion of sequestered carbon contributing to net climate benefit. Results showed that FSB and RFbio were "broadly" aligned, but ME varied with the magnitude and duration of biogenic emissions. The scenarios BIOE (bioenergy) and TM (modular cutting) achieved high FSB but showed lower ME due to concentrated or sustained emissions. WOOD (promotion of long-lived wood) and ADAPT (adaptation management) yielded higher ME under SSP1-2.6, while several strategies (WOOD, ADAPT, TRANS) became net sources under SSP5-8.5 after 2200. Substitution benefits declined under degressive assumptions, reducing mitigation by up to 53% especially for high-harvest scenarios. FSB was primarily shaped by climate and management, secondly by substitution, however; wood-use strategies had no significant long-term effect provided they did not impact resource availability. Together, these findings underscore that effective forest-sector mitigation requires not only maximizing cumulative carbon stocks, but also minimizing the magnitude, timing, and atmospheric residence time of emissions while carefully considering the role of substitution benefits. HighlightsO_LIThe long-term forest sector carbon balance is mainly governed by active management, climate conditions, and wood substitution pathways. C_LIO_LIForest Sector Balance as a metric is "broadly" aligned with the radiative forcing from biogenic emissions C_LIO_LIThe mitigation efficiency of forest sector options depends on emissions timing, duration, and amplitude C_LIO_LISubstitution factors also known as displacement factors need to be considered with greater caution C_LI

ecology↗

bioRxiv2023

Stand age diversity dampens forests sensitivity to climate change

Stand age significantly influences the functioning of forest ecosystems by shaping structural and physiological plant traits, affecting water and carbon budgets. Forest age distribution is determined by the interplay of tree mortality and regeneration, influenced by both natural and anthropogenic disturbances. Thus, human-driven alteration of tree age distribution presents an underexplored avenue for enhancing forest stability and resilience. In our study, we investigated how age distribution impacts the stability and resilience of the forest carbon budget under both current and future climate conditions. We employed a biogeochemical model on three historically managed forest stands, projecting their future as undisturbed systems, i.e., left at their natural evolution with no management interventions. The model, driven by climate data from five Earth System Models under four representative climate scenarios and one baseline scenario, spanned 11 age classes for each stand. Our findings indicate that Net Primary Production (NPP) peaks in the young and middle-aged classes (16- to 50-year-old), aligning with ecological theories, regardless of the climate scenario. Under climate change, the beech forest exhibited an increase in NPP and maintained stability across all age classes, while resilience remained constant with rising atmospheric CO2 and temperatures. However, NPP declined under climate change scenarios for the Norway spruce and Scots pine sites. In these coniferous forests, stability and resilience were more influenced. These results underscore the necessity of accounting for age classes and species-specific reactions in evaluating the impacts of climate change on forest stability and resilience. We, therefore, advocate for customized management strategies that enhance the adaptability of forests to changing climatic conditions, taking into account the diverse responses of different species and age groups to climate.

plant biology↗

bioRxiv2023

Regional estimates of gross primary production applying the process-based model 3D-CMCC-FEM vs. multiple datasets

Process-based Forest Models (PBFMs) offer the possibility to capture important spatial and temporal patterns of both carbon fluxes and stocks in forests, accounting for ecophysiological, climate and geographical variability. Yet, their predictive capacity should be demonstrated not only at the stand-level but also in the context of large spatial and temporal heterogeneity. For the first time, we apply a stand scale process-based model (3D-CMCC-FEM) in a spatially explicit manner at 1 km spatial resolution in a Mediterranean region in southern Italy. Specifically, we developed a methodology to initialize the model that comprehends the use of spatial information derived from the integration of remote sensing (RS) data, the national forest inventory data and regional forest maps to characterize structural features of the main forest species. Gross primary production (GPP) is simulated over the period 2005-2019 and the multiyear predictive capability of the model in simulating GPP is evaluated both aggregated as at species-level by means of independent multiple data sources based on different RS-based products. We show that the model is able to reproduce most of the spatial ([~]2800 km2) and temporal (32 years in total) patterns of the observed GPP at both seasonal, annual and interannual time scales, even at the species-level. These new very promising results open the possibility of applying the 3D-CMCC- FEM confidently and robustly to investigate the forests behavior under climate and environmental variability over large areas across the highly variable ecological and bio- geographical heterogeneity of the Mediterranean region. Key PointsO_LIWe apply a process-based forest model on a regular grid at 1 km spatial resolution in a Mediterranean region. C_LIO_LIInitial forest state is estimated using spatially explicit input data derived from remote sensing and national forest inventory data. C_LIO_LIThe 3D-CMCC-FEM shows comparably estimates in simulating both spatial and temporally the gross primary production, when compared to independent satellite-based products. C_LI

ecology↗

bioRxiv2022

Simulating alternative forest management in a changing climate on a Pinus nigra subsp. laricio plantation in Southern Italy

Mediterranean pine plantations provide several ecosystem services but are particularly sensitive to climate change. Forest management practices might play a strategic role in the long-term adaptation of Mediterranean forests, but the joint effect of climate change and alternative management options in the near and far future have seldom been investigated together. Here, we developed a portfolio of management options and simulated the development of a Laricio pine (Pinus nigra subsp. laricio) stand in the Bonis watershed (southern Italy) from its establishment in 1958 up to 2095 using a state-of-the-science process-based forest model. The model was run under three climate change scenarios corresponding to increasing levels of atmospheric CO2 concentration, and seven management options with different goals, including post-disturbance management, wood production and renaturalization purposes. We analyzed the effect of climate change on annual carbon fluxes (i.e., gross and net primary production) and stocks (i.e., basal area and potential carbon woody stocks), as well as the impact of different management options compared to no management. Results show that, while climate change (i.e., warming and enriched atmospheric CO2 concentration) seems to increase carbon fluxes and stocks in the first half of the century, both show a substantial decrease in the second half, along with higher temperatures (+3 to +5 {degrees}C) and lower precipitation (-20% to -22%). When compared to no management, alternative options had a moderate effect on carbon fluxes over the whole simulation (between -6% and +7%) but overall carbon stocks were maximized by thinning interventions and the shelterwood system (+54% to +55%). We demonstrate that the choice of management exerts greater effects on the features of Laricio pine plantations than climate change alone. Therefore, silvicultural strategies might enhance potential stocks and improve forest conditions, with cascading positive effects on the provision of ecosystem services in Mediterranean pine plantations. HighlightsO_LIWe simulated the development of a Laricio pine stand over 137 years under three different climatic scenarios and seven management options. C_LIO_LICarbon fluxes and stocks benefit from climate change (i.e., warming and enriched atmospheric CO2 concentration) in the first half of the century but show a marked decrease in the longer-term. C_LIO_LIForest management exerts a much stronger effect on these features than climate change alone. C_LIO_LISilvicultural options aimed at reducing stand density preserve and enhance carbon fluxes and stocks over the simulated time period. C_LI

ecology↗

bioRxiv2022

No leeway to enhance carbon sequestration and stock capacity via changes to forest management

Forest management practices might act as nature-based methods to remove CO2 from the atmosphere and slow anthropogenic climate change and thus support an EU forest-based climate change mitigation strategy. However, the extent to which diversified management actions could lead to quantitatively important changes in carbon sequestration and stocking capacity at the tree level remains to be thoroughly assessed. To that end, we used a state-of-the-science bio-geochemically based forest growth model to simulate effects of multiple forest management scenarios on net primary productivity (NPP) and potential carbon woody stocks (pCWS) under twenty scenarios of climate change in a suite of observed and virtual forest stands in temperate and boreal European forests. Previous modelling experiments indicated that the capacity of forests to assimilate and store atmospheric CO2 in woody biomass is already being attained under business-as-usual forest management practices across a range of climate change scenarios. Nevertheless, we find that on the long-term, with increasing atmospheric CO2 concentration and warming, managed forests show both higher productivity capacity and a larger potential pool size of stored carbon than unmanaged forests as long as thinning and tree harvesting are of moderate intensity.

ecology↗