Field surveys of ozone symptoms in Europe. Problems, reliability and significance for ecosystems

<p>The ICP-Forest program for the monitoring of forest conditions includes the assessment of ozone symptoms in the European forests. This contribute to discussion points out the problems related to the recognition of such symptoms, with a special focus on the difficulties to extend the results obtained in experimental conditions to woody plant species growing in the field. Non specific symptoms (such as reddening, yellowing, early senescence and leaf loss), and the concurrent action of modifying factors (high light, drought, nutrient deficiency, pest attack and fungi) make the recognition elusive. In these cases, the action of ozone cannot be proven or excluded with “ad hoc” experiments. Apparently “good” bioindicators (<em>Rubus</em> sp. <em>Cornus</em> sp. pl., <em>Prunus</em> sp. pl., <em>Viburnum</em> sp. pl. etc.)  are not suitable to assess the impact of ozone on vegetation. Symptoms are not necessarily related to the ozone dose taken up by stomata, and don’t are reliable indicator for biomass and productivity losses. Symptoms can be considered an epiphenomenon of more complex ecosystem processes.</p

Editorial to: "A challenge for the analysis of environmental stress. The measurement of chlorophyll a fluorescence (ChlF) from plants to ecosystems"

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Do tree-species richness, stand structure and ecological factors affect the photosynthetic efficiency in European forests?

No abstract available

Traditional and novel indicators of climate change impacts on European forest trees

The concern for the fate of forest ecosystems under climate change demands the development of a prompt and effective system for detecting the impacts of pressure factors, such as rising temperatures, drought conditions, and extreme climatic events. In ongoing European monitoring programs, the health condition of trees is only assessed visually as a matter of course and there is limited evidence that enhanced crown defoliation implies physiological disturbance and reduced tree growth. The progress of the research makes it possible to apply methods developed in experimental conditions in forests for the fast and reliable assessment of impacts and of stress conditions. In this review, we analyze the most promising indicators of tree and forest health (at individual plant and ecosystem levels) for their potential application in forest ecosystems and their ability to support and integrate the traditional visual assessment, provide information on influential factors, and improve the prediction of stand dynamics and forest productivity

Linking forest diversity and tree health: preliminary insights from a large-scale survey in Italy

Forest health is currently assessed in Europe (ICP Forests monitoring program). Crown defoliation and dieback, tree mortality, and pathogenic damage are the main aspects considered in tree health assessment. The worsening of environmental conditions (i.e., increase of temperature and drought events) may cause large-spatial scale tree mortality and forest decline. However, the role of stand features, including tree species assemblage and diversity as factors that modify environmental impacts, is poorly considered. The present contribution reanalyses the historical dataset of crown conditions in Italian forests from 1997 to 2014 to identify ecological and structural factors that influence tree crown defoliation, highlighting in a special manner the role of tree diversity. The effects of tree diversity were explored using the entire data set through multivariate cluster analyses and on individual trees, analysing the influence of the neighbouring tree diversity and identity at the local (neighbour) level. Preliminary results suggest that each tree species shows a specific behaviour in relation to crown defoliation, and the distribution of crown defoliation across Italian forests reflects the distribution of the main forest types and their ecological equilibrium with the environment. The potentiality and the problems connected to the possible extension of this analysis at a more general level (European and North American) were discussed

Tree inventory data of Pinus nigra J.F.Arnold subsp. laricio (Poir.) Maire in southern Italy

The dataset supplied in this article provides data from a stand of Pinus nigra J.F.Arnold subsp. calabrica (Poir.) Maire (Calabrian black pine) characterized by old trees, with a relevant role for forest community biodiversity. Natural stands of Calabrian black pine have both outstanding conservation and cultural values, to be taken under consideration in forest and land uses management and monitoring plans.A time series of dendrometric parameters is provided for 58 pine trees: the data were collected during three forest surveys (in 1976, 1986 and 2016). These data, in combination with other forest stand and environmental parameters, may effectively contribute to understand the dynamics of Calabrian black pine forests in southern Italy, thus how the natural and human disturbances have affected the structure and species composition of these forest ecosystems with high ecological value.Dataset access at https://zenodo.org/record/1100340. Associated metadata available at https://zenodo.org/record/110034