Search

• Remote sensing indexes and tree-rings/wood anatomy data were compared. • High variability among sites and tree species in their responses to drought. • Ash seem to perform better then oak in terms of growth under drought. • Relevant effect for forest management and ecosystem services. Drought reduces canopy cover, productivity and tree growth in forests. However, there is still little knowledge on how drought affects coupling between canopy greenness assessed by remote sensing and hydraulic conductivity detected by wood anatomy. This combination could improve the understanding of forest response to climate change. Thus, we investigated the impacts of a hot drought, which occurred in summer 2017, on radial growth, earlywood hydraulic diameter (Dh), a proxy of conductivity, and several remote-sensing indices in mixed Mediterranean hardwood forests (Quercus pubescens Willd. – Fraxinus ornus L.). In general, growth showed a higher coherence among trees and a higher responsiveness to climate. Growth decreased during the drought year, particularly for Q. pubescens , which showed high defoliation and dieback intensity. Both species showed a decline of Dh in 2018 after the drought and subsequent warm winter conditions. We found positive relationships between Dh and remote-sensing data for Q. pubescens in some of these vulnerable sites, where (i) growth was constrained by dry spring-summer conditions and (ii) Dh and growth covaried. These findings indicate a high variability among sites and tree species in their responses to drought considering earlywood anatomy, growth canopy cover and water content. However, some common patterns emerge such as links between potential hydraulic conductivity (Dh), tree cover and Dh-growth covariation in the most impacted sites. Further, F. ornus seem to perform better in terms of growth under drought conditions, showing less mortality and dieback than Q. pubescens. Future studies could explore how water transport and changes in canopy cover respond to dry and warm conditions and if that covariation indicates vulnerability to drought. [ABSTRACT FROM AUTHOR]

This study investigated the impact of different types of soil sealing on the communities of a group of beneficial plant symbionts, arbuscular mycorrhizal fungi (AMF), colonizing the roots of two shade trees, Celtis australis and Fraxinus ornus , frequently grown in urbanized sites. Such plants were grown in an experimental site, in northern Italy, established in November 2011 and subjected to four different pavement treatments: impermeable monolithic asphalt, permeable pavers, permeable concrete and unpaved soil. The diversity and composition of root AMF communities were assessed by PCR denaturating gradient gel electrophoresis of partial 18S rRNA gene, AMF taxa were identified by amplicon sequencing and mycorrhizal colonization was evaluated after root clearing and staining. For the first time, our molecular work revealed that impermeable pavements induced shifts in the composition of AMF communities associated to the roots of C. australis and F. ornus and impacted on the percentage of mycorrhizal root length. When the root-zone was covered with permeable pavements, a similar AMF community as that observed in the unpaved soil was detected, providing novel information to be utilised for reducing the disturbance caused by specific types of soil sealing on AMF symbionts, which play a key role in plant nutrition and health. A total of 45 AMF sequence types were detected, with Sclerocystis and Septoglomus as the most abundant phylotypes, accounting for 84% of the sequences. The predominance of Sclerocystis species in the roots of both tree species under impermeable pavements indicated their high and unforeseen tolerance towards harsh environmental conditions. Such species could be utilized as AMF inocula specifically selected for their proven resilience in paved sites, in order to exploit their ability to boost biogeochemical processes fundamental for energy fluxes and plant nutrition and health. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to establish the influence of species and land preparation method on the maintenance of saplings planted on degraded lands due to sheet erosion in Frata amelioration perimeter (Cluj county, Romania) we used black locust (Robinia pseudoacacia) and manna ash (Fraxinus ornus). The land preparation methods used were terraces and pits. We established the saplings maintenance degree in the first year after planting. To establish the influence of species and antierosional land preparation on the maintenance of saplings planted and which stroke roots, we placed two experiment (bifactorial). The significance of the differences between the tested variants was shown using Duncan (Tuckey) test of multiple comparisons, considering significant differences DS5%. As compared to manna ash, the black locust provided the highest saplings maintenance degree, at an insignificant difference. Terracing, as antierosional land preparation provides the highest maintenance degree at an insignificant difference as compared to the pits, no matter the species involved. The variants which provided the highest maintenance degree were manna ash x wattle fence terraces and black locust x wattle fence terraces and the lowest maintenance degree was registered by the manna ash planted in pits. [ABSTRACT FROM AUTHOR]

• High pine cover favoured late successional resprouter seedling survival. • Seedlings growth response to pine cover depended on their functional strategy. • Pine-seedling interactions were noticeable after 2 years, intensifying with time. • We need long-term monitoring to assess plant interactions and restoration success. Monospecific pine forests are widespread due to extensive afforestation efforts and natural colonization of abandoned croplands in the Mediterranean Basin. It was originally thought that pines would facilitate the natural colonization of native late-successional resprouter species (e.g., hardwoods), but these species can be compromised if competition with pines outweighs their facilitative effect on these hardwood species. Managing the density or canopy cover of these widespread pine forests can potentially provide some "optimum" balance between facilitation and competition to maximize success in the introduction of late successional species while maintaining a tree stratum. We tested the response (survival and growth across 10 years) of six resprouter species covering a wide range of plant functional strategies, from drought-tolerant sclerophyllous shrubs and trees to malacophyllous drought-sensitive trees, across an experimental gradient of Aleppo pine canopy cover. Seedling performance varied according to the functional strategy, pine cover and time. High pine cover generally enhanced seedling survival, whereas moderate pine cover generally enhanced seedling growth, although this response was modulated by the functional strategy of the seedling species. Interactions between pines and seedlings were only detectable 2–3 years after plantation, increasing in intensity with time. The latter highlights the need of medium to long-term studies to evaluate plant-plant interactions in these water-limited environments with slow successional trajectories. Our results could be attributed to the shade tolerance of most of the introduced trees, combined with their low tolerance to the combination of high sunlight radiation and drought. We found an optimal pine cover of ca. 50% (equivalent to 300–400 trees/ha) in which both survival and growth of late successional species can be maximized, which help to select best locations for more efficient reforestation programs and set a threshold value to decide whether or not to perform tree thinning to enhance ecosystem diversity and, subsequently, resilience. [ABSTRACT FROM AUTHOR]

The article focuses on a study about the potential protective effects of Fraxinus ornus on broiler chickens experimentally infected with Eimeria tenella. Chickens were divided in groups that were infected and not infected, and their growth parameters, oocyst excretion, haematocrit values and caecal lesion have been determined for the whole 35 days. According to the findings, there was moderate development of coccidiosis as defined by the presence of oocysts in feces and caecal lesions in experimentally infected birds. It is inferred that Fraxinus ornus present in the ration produced a coccidiostatic effect against Eimeria tenella.