In the context of climate change, the stable isotope analysis of tree rings may play a crucial role in deciphering the eco-physiological mechanisms underlying forest decline and dieback phenomena. ...However, this technique is often considered expensive, time-consuming, and with several methodological constraints. Specifically, milling and transferring the material from jars to vials during the different steps of sample preparation involve risk of contamination among samples and loss of sample material. When dealing with declining trees (i.e., trees affected by loss of vitality with strong percentage of defoliation and reduction in growth) and trees subjected to extreme events or negative pointer years (characterized by extremely narrow ring) the sample preparation is particularly difficult because of scarce amount of wood material. In such a case, pooling rings from several years to achieve the minimum weight of wood is often necessary, thus losing information at the annual resolution. In order to overcome such limitations, we developed a novel protocol for quick and accurate whole-wood pre-processing, testing it on oak tree rings of different widths taken from living trees. The main novelty introduced by our protocol was freezing tree-ring samples at −80 °C and milling multiple samples at a time by using a 24-tube plate. The results showed that our novel simplified protocol significantly reduced the pre-processing time with respect to the standard protocol (12 vs. 284 sec/sample), while achieving the same wood particle size, limiting the loss of wood material and reducing the risk of contamination among samples.
Presently, the forests of one of the most economically important tree species in Europe—Norway spruce Picea abies (L.) Karst.—have been disrupted and are in rapid decline due to a combination of ...several natural factors: extreme drought, heatwaves, and secondary damage caused by bark beetle outbreaks. The vulnerability of these forests has increased considerably over the past decade, and remote sensing methods can theoretically improve the identification of endangered forest stands. The main objective was to determine the relationship between remotely sensed characteristics of vegetation (using the normalized difference vegetation index—NDVI) and annual tree-ring growth in 180 trees through precipitation and air temperature. The research was conducted at six research plots in lowland spruce forests (319–425 m a.s.l.) in the central Czech Republic. No significant correlation between NDVI and annual ring width was observed. The primary factor limiting radial growth was lack of precipitation in the growing season; subsequently, spruce trees reacted negatively to air temperatures. A higher correlation with NDVI was observed on sites susceptible to drought, but overall, NDVI and RWI did not show similarities. This result describes that NDVI is a poor indicator for identifying low radial growth in Norway spruce stands on non-native localities in the studied area.
Key message
Managing forest residues according to the carbon content of the soil helps to minimize the ecological footprint of their removal.
Context
In Mediterranean mountain ecosystems, ...unsustainable harvesting of wood residues might contribute to land degradation, carbon, and nutrient depletion in forest soils.
Aims
This study aimed to assess the amount of forest biomass residues that should be left on-site to minimize the depletion of soil fertility.
Methods
We estimated the availability of biomass residues in the public forest land of the Basilicata region of Southern Italy by collecting stand-scale inventory attributes from forest management plans. Subsequently, we quantified the amount of forest biomass residue released by implementing a scenario-based approach.
Results
Approximately 5800 m
3
year
−1
of forest residues could be potentially available for bio-based industries at the regional scale within the next 10 years. Such residues mainly belong to broadleaved forest types, having a high variability in their soil organic stock (228.5–705.8 Mg C ha
−1
) and altitudinally spanning from 400 to 1500 m a.s.l. In these forests, the simulated scenarios displayed a wide range of average harvestable residues from 2.5 to 5.5 m
3
ha
−1
, containing approximately 1.1 to 2.1 Mg ha
−1
of organic carbon.
Conclusion
Our study suggests that forest management plans are a useful source of information to estimate the available forest biomass residues consistently. In southern Mediterranean mountain forests, the management of forest residues according to soil carbon content helps to minimize the environmental impact and increase their sustainability.
Norway spruce (Picea abies (L.) Karst.) is a significant conifer tree species in Europe that holds significant economic and ecological value. However, it remains one of the most sensitive to climate ...change. This study describes the climate–growth relationship, focusing on dendroecology in hilly spruce forests (319–425 m a.s.l.) located in Bohemia, the Czech Republic, during 1950–2018. The results confirmed that the highest radial increment was obtained in locations with higher precipitation (Kostelec), while the lowest growth was observed in locations with lower precipitation (Karlstejn). Tree-ring growth shows very low increments for the years 1964 and 1976 for all plots, and the years with the least growth were confirmed by the negative pointer year analysis. This study confirmed precipitation as the main factor that affects the growth of spruce at lower altitudes. The radial growth for all study sites shows a statistically significant positive correlation with precipitation during the growing season, while no statistically significant values between radial growth and temperature were obtained. This study demonstrates that Norway spruce is affected more by precipitation than temperature, and the results indicate that this conifer is seriously affected by the lack of precipitation at lower altitudes in the Czech Republic, where the species is not native.
•Floodplain and riparian forests are among the most vulnerable ecosystems.•We compared growth of coexisting trees in a temperate and Mediterranean conditions.•Climate and tree-ring data were combined ...with growth models to detect growth decline.•Warmer springs and drier summers reduce oak and ash growth.•Alder was the most drought resistant species.
Floodplain forests are sensitive to climate warming and increased drought, as showed by recent oak (Quercus robur) dieback and mortality episodes. However, a comprehensive comparison of coexisting tree species under different climate settings or biomes are lacking. Herein, we compared growth rates, growth responses to climate and drought severity, and modeled climate mediated growth of oak and three coexisting tree species (ash, Fraxinus angustifolia; alder, Alnus glutinosa; elm, Ulmus minor). Two floodplain forests subjected to cooler (temperate climate, Ticino) and warmer (Mediterranean climate, Bosco Pantano) conditions in northern and southern Italy, respectively, were analyzed. Ash seemed to be the most sensitive to drought, particularly at the Mediterranean site where oak and elm growth were also negatively affected by water shortages. Alder appeared to be the least sensitive species in terms of growth variability to drought under both temperate and Mediterranean climate conditions. Furthermore, the growth model revealed the influence of soil moisture in spring and summer on the constrained growth of ash and oak and illustrated how oak growth could be severely reduced during drastic hotter droughts. Alder seemed to be the most drought-resistant species under both environmental conditions. These results could represent the first attempts in documenting the ecological consequences of drought in terms of projected climate trends in less investigated Mediterranean floodplain forests. Furthermore, these results highlight how climate and tree-ring data combined with growth models could be useful tools to detect early warning signals of growth decline and impending dieback in floodplain forests in response to dry spells.
Norway spruce (Picea abies (L.) Karst.) is a significant conifer tree species in Europe that holds significant economic and ecological value. However, it remains one of the most sensitive to climate ...change. This study describes the climate–growth relationship, focusing on dendroecology in hilly spruce forests (319–425 m a.s.l.) located in Bohemia, the Czech Republic, during 1950–2018. The results confirmed that the highest radial increment was obtained in locations with higher precipitation (Kostelec), while the lowest growth was observed in locations with lower precipitation (Karlstejn). Tree-ring growth shows very low increments for the years 1964 and 1976 for all plots, and the years with the least growth were confirmed by the negative pointer year analysis. This study confirmed precipitation as the main factor that affects the growth of spruce at lower altitudes. The radial growth for all study sites shows a statistically significant positive correlation with precipitation during the growing season, while no statistically significant values between radial growth and temperature were obtained. This study demonstrates that Norway spruce is affected more by precipitation than temperature, and the results indicate that this conifer is seriously affected by the lack of precipitation at lower altitudes in the Czech Republic, where the species is not native.
Abstract Water transport, mechanical support and storage are the vital functions provided by the xylem. These functions are carried out by different cells, exhibiting significant anatomical variation ...not only within species but also within individual trees. In this study, we used a comprehensive dataset to investigate the consistency of predicted hydraulic vessel diameter widening values in relation to the distance from the tree apex, represented by the relationship Dh ∝ Lβ (where Dh is the hydraulic vessel diameter, L the distance from the stem apex and β the scaling exponent). Our analysis involved 10 Fagus sylvatica L. trees sampled at two distinct sites in the Italian Apennines. Our results strongly emphasize that vessel diameter follows a predictable pattern with the distance from the stem apex and β ~ 0.20 remains consistent across cambial age and climates. This finding supports the hypothesis that trees do not alter their axial configuration represented by scaling of vessel diameter to compensate for hydraulic limitations imposed by tree height during growth. The study further indicates that within-tree variability significantly contributes to the overall variance of the vessel diameter-stem length exponent. Understanding the factors that contribute to the intraindividual variability in the widening exponent is essential, particularly in relation to interspecific responses and adaptations to drought stress.
