This innovative environmental history of the long-lived European chestnut tree and its woods offers valuable new perspectives on the human transition from the Roman to the medieval world in Italy. ...Integrating evidence from botanical and literary sources, individual charters and case studies of specific communities, the book traces fluctuations in the size and location of Italian chestnut woods to expose how early medieval societies changed their land use between the fourth and eleventh centuries, and in the process changed themselves. As the chestnut tree gained popularity in late antiquity and became a valuable commodity by the end of the first millennium, this study brings to life the economic and cultural transition from a Roman Italy of cities, agricultural surpluses and markets to a medieval Italy of villages and subsistence farming.
Chestnuts have been consumed in Portugal for immemorial times. These fruits are highly appreciated, not only due to their organoleptic characteristics but also due to their nutritional and functional ...values. For the nutrients to be more accessible and for the chestnuts to have better flavour and digestibility, it is necessary to heat, cook or roast them, for example. Chestnuts are a very versatile food, in terms of preparation, and can be cooked, roasted, as an accompaniment to dishes, replacing rice, pasta or potatoes, in the base of soups or the preparation of appetizing desserts and cakes. In Portugal the use of chestnuts to produce differentiated food products is traditional, but also new and innovative products are appearing on the market, either made with chestnuts or even with some residues of their processing, in the context of a circular economy. Examples of traditional usages of chestnut in Portugal include chestnut soup, or roasted chestnuts, which are typically consumed in the colder months of autumn and winter. In what concerns more modern trends, the use of chestnut flour to incorporate into a variety of foods, like bread, cookies or pasta is highlighted. This article explores the value of the chestnut sector in Portugal and the use of these fruits to obtain either traditional or innovative foods, such as bread, biscuits, pasta and beverages.
Starch retrogradation is a mechanism that is associated with the quality of starch-based food products. A thorough understanding of chestnut starch retrogradation behavior plays an important role in ...maintaining the quality of chestnut foods during processing and storage. In this study, we investigated the effects of storage time on the structural properties and in vitro digestibility of gelatinized chestnut starch by using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and solid-state 13C nuclear magnetic resonance (NMR). The results showed that the long-range crystallinity and short-range molecular order of retrograded chestnut starch first rapidly increased from 3 h to 3 d and then decreased from 3 d to 7 d, followed by a slight increase from 7 d to 14 d with retrogradation. With the extension of storage time at 4 °C, there were generally obvious increases in single and double helical structures, which were stacked into long-term ordered structure, resulting in increased enthalpy changes as detected by differential scanning calorimetry spectroscopy (DSC) and reduction of the digestion rate of retrograded chestnut starch. Overall, this study may provide important implications for manipulating and improving the quality of chestnut foods.
•Retrogradation behavior and in vitro digestibility of chestnut starch stored at 4 °C from 3 h to14 d were studied.•The molecular order increased and then decreased slightly during retrogradation.•The RS contents increased with the extension of storage time.
The American chestnut (AC; Castanea dentata (Marsh.) Borkh.) once dominated the forests of eastern North America prior to the introduction of chestnut blight in the late 19th century. A somatic ...embryogenesis (SE) system developed for American chestnut is potentially applicable for clonally propagating blight-resistant trees produced by The American Chestnut Foundation’s hybrid backcross breeding program. In this program, AC trees are hybridized with blight-resistant Chinese chestnut (CC; Castanea mollissima Blume) trees, followed by multiple generations of backcrossing to AC trees. It is possible, however, that the proportion of CC parental contribution in the hybrid backcross material could affect the success of SE using the AC protocol. Over three years of culture initiations, we tested the effects of the relative parental contributions of AC and CC on the success of SE induction using our standard AC culture initiation protocol and, subsequently, a published protocol for SE in European chestnut (Castanea sativa Mill.). With our standard AC protocol, open-pollinated AC and open- and control-pollinated hybrid backcross BC3F3 seed explants, as well as open-pollinated BC2 seed explants, successfully produced embryogenic tissue, while CC, F1, and BC1 explants did not. The European chestnut protocol produced Chinese chestnut embryogenic tissue and, subsequently, somatic embryos. The first BC3F3 somatic seedlings are currently growing in field tests.
•Natural seed regeneration of chestnut is a key issue in recovering overaging chestnut coppices.•The establishment of seed regeneration was more than sufficient to guarantee a safe turnover of dead ...stools.•Chestnut trees released (standards) after coppicing do not play a relevant role as tree-seeders.•The presence of standards inhibited the growth of seedlings up to 10 m away.•An excessive presence of standards has promoted the settling of regeneration of shade-tolerant species.
The management of Italian chestnut coppices has gradually been suspended after World War II, causing a widespread overaging of the concerned stands. In recent years, the renewed interest in coppice wood products increased the need of a solid knowledge on the most suitable restoration practices of overaged coppices.
In this context, a key issue is assuring a qualitative and abundant seed regeneration of the chestnut tree (Castanea sativa Miller) in order to substitute overaged stools. Open questions still exist however on the role of the standards (trees released after coppicing) and, in particular, on their interaction with the post-coppicing establishment of seed regeneration.
In order to clarify these aspects, we applied different coppicing systems in overaged chestnut coppices so as to create a gradient of residual coverage ranging from full coverage left (no intervention) to simple coppicing (all trees cut, no standards released). The impact of different treatments on chestnut regeneration has been then assessed through field surveys in the second and fifth year post-coppicing, respectively.
Chestnut seed regeneration promptly and abundantly established to guarantee the replacement of dead stools also in the simple coppicing. The post-coppicing pulse of chestnut seed regeneration mostly originated from the existing annual seed bank and it was concentrated in the first two years after the intervention, whereas seed inputs by standards or by adult trees at the forest edge played a secondary or negligible role from the third post-coppicing year onwards. Thus, the presence of standards did not benefit regeneration. Rather, it displayed a marked depressive effect on the growth rate of young chestnut seedlings and, under significant shading conditions, enhanced the establishment of shade-tolerant tree species.
From a silvicultural point of view, simple coppicing of overaged chestnut coppices represents a valuable management option combining a rapid establishment of natural seed regeneration of chestnut with the resprout and development of the most vigorous stools.
Biological control of Cryphonectria parasitica fungus, causal agent of chestnut blight, by virus infection (hypovirulence) has been shown to be an effective control strategy against chestnut blight ...in Europe and some parts of North America. The most studied mycovirus is the Cryphonectria hypovirus 1 (CHV-1) type species of the Hypoviridae family. To efficiently provide biocontrol, the virus must be able to induce hypovirulence in its fungal host in chestnut trees. Here, two different CHV-1 subtype I virus strains (E-5 and L-18), gained by transmissions, were tested for their hypovirulence induction, biocontrol potential, and transmission between vegetatively compatible (VCG) and incompatible fungal isolate groups in sweet chestnut seedlings and branches. Both strains of CHV-1 showed great biocontrol potential and could protect trees by efficiently transmitting CHV-1 by hyphal anastomosis between fungal isolates of the same VCG and converting virulent to hypovirulent cankers. The hypovirulent effect was positively correlated with the virus concentration, tested by four different reverse-transcription PCRs, two end-point and two real-time methods, one of which represents a newly developed real-time PCR for the detection and quantification of CHV-1.
Chestnut breeding programs have been using a backcross breeding technique to produce trees with a predominantly American chestnut (Castanea dentata (Marsh.) Borkh.) genome and chestnut blight disease ...resistance from Asian species like the Chinese chestnut (Castanea mollissima Blume). The potential for other physiological changes caused by breeding has yet to be widely studied. We quantify chestnut (American, Chinese, and BC
3
F
3
hybrids) responses to water-stress and measure how co-occurring drought influences disease severity. The experiment was completed using 172 bare-root seedlings organized into a completely randomized factorial design in an outdoor rain-out shelter for one growing season. BC
3
F
3
hybrid gas exchange (A
sat
, g
s
) rates were more similar to Chinese than American chestnuts over a 20-day dry-down period, and hybrid turgor loss point showed a more intermediate (between Chinese and American) response. The relationship of stomatal conductance to midday leaf water potential (Ψ
md
) also exhibited both American and Chinese characteristics in the hybrid trees. There was no effect of drought on the disease severity for any of the chestnut groups. We find evidence that drought physiology has been altered in some BC
3
F
3
hybrids, but do not find changes in disease severity when chestnuts are under co-occurring drought.
The invasion of the Asian chestnut gall wasp Dryocosmus kuriphilus (ACGW) in Europe has caused serious biological and economic impacts on chestnut stands that have been partially solved with the ...introduction of the biological control agent Torymus sinensis. However, information concerning tree‐ring growth during the ACGW epidemic has been lacking so far.
Using dendrochronology techniques, we analysed the impact of the ACGW on tree‐ring growth and the capacity of the chestnut tree to recover when biocontrol was achieved in seven sites covering the area of first detection and subsequent spread of the ACGW in Europe. In each site, a non‐target control species (i.e. trees not attacked by the ACGW) has been included as a reference in the analysis.
Results show a reduction in the tree‐ring increment by 60% on average during the ACGW epidemic. Such effects were higher in the magnitude and longer in the duration when compared to other stresses such as insect defoliation or extreme summer droughts.
Synthesis and applications. Marked reductions in radial growth were evident in the years of ACGW attack regardless of the age of the chestnut coppices. Since most of the trees only recovered to an almost normal growth rate after 3–4 years of biocontrol by T. sinensis, an immediate release of the antagonist at the first ACGW appearance is highly recommended. The consequences and perspectives of ACGW's attacks on the quality of the timber produced are also discussed.
Marked reductions in radial growth were evident in the years of ACGW attack regardless of the age of the chestnut coppices. Since most of the trees only recovered to an almost normal growth rate after 3–4 years of biocontrol by T. sinensis, an immediate release of the antagonist at the first ACGW appearance is highly recommended. The consequences and perspectives of ACGW's attacks on the quality of the timber produced are also discussed.
In this study, the antioxidant properties of chestnut (flowers, leaves, skins and fruits) extracts were evaluated through several biochemical assays: DPPH (2,2-diphenyl-1-picrylhydrazyl) ...radical-scavenging activity, reducing power, inhibition of β-carotene bleaching, inhibition of oxidative hemolysis in erythrocytes, induced by 2,2′-azobis(2-amidinopropane)dihydrochloride (AAPH), and inhibition of lipid peroxidation in pig brain tissue through the formation of thiobarbituric acid-reactive substances (TBARS). These assays have been extensively studied as models for the peroxidative damage in biomembranes. The EC
50 values were calculated for all the methods in order to evaluate the antioxidant efficiency of each chestnut extract. The phenol and flavonoid contents were also obtained. Chestnut skins revealed the best antioxidant properties, presenting much lower EC
50 values, particularly for lipid peroxidation inhibition in the TBARS assay. Furthermore, the highest antioxidant contents (polyphenols and flavonoids) were found for these extracts.
•Soil fungi with Fagaceae reforestation shifts similarly between oaks and chestnuts.•Chestnut species and backcrossed hybrids share many common ectomycorrhizae.•Many taxa, including ectomycorrhizal ...fungi are established during planting.•American chestnut had fewer plant pathogens detected than other species.
Forests of the Southern Appalachian Mountains were historically dominated by hardwood species within the family Fagaceae, e.g., American chestnut (Castanea dentata) and white oak (Quercus alba) among others. Due to numerous biotic and abiotic stressors, including pathogen pressure, populations of many Fagaceae have been greatly reduced, or functionally eliminated as is the case with American chestnut. This has led to reforestation efforts designed to increase American chestnut and white oak populations in this region, but success has been minimal. Since soil fungal communities are crucial to plant health, understanding how reforestation efforts alter soil fungal communities will inform reforestation efforts. Here, using nursery-reared bareroot seedlings of American chestnut, Chinese chestnut, 3rd generation backcross chestnut hybrids (BC3F3), and white oaks outplanted at a locally xeric site in the Southern Appalachian Mountains, we investigated if and how these species and backcross families within species differentially impact soil fungal communities. We demonstrate that after three years of growth, plant-associated soil fungal communities change similarly among different Fagaceae and are distinct from pre-planting soil communities. Interestingly, we observed differential shifts in fungal functional guilds among the Fagaceae species, although these were rather minimal. Taken together, the largely convergent shifts in soil communities across Fagaceae species suggest that these tree species may have similar impacts on soils and/or share similar communities that become enriched in closely related fungal species. The similarity in shared mutualist fungal communities suggests that companion planting or reforestation of genetically disease resistant American chestnut adjacent to establishing white oak trees might enhance survival and growth of both species at xeric sites.
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