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

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

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

Were there significant changes in the overall condition of the CONECOFOR plots over the 1995 -2005 period?

Since 1995 the CONECOFOR programme is collecting data on a number of attributes of forest ecosystems in 20 permanent plots in Italy. In this paper, different multivariate methods were used to detect possible changes and deviations in the overall biological and chemical-physical status of the CONECOFOR plots as compared to defined reference periods. The reference periods were set-up taking into account the data availability and were as follows: 1997-1999 for biological status; 1999-2002 for chemical-physical status. Changes of the biological conditions of the plots were identified only in a few cases over the period 2000 - 2004 and were due to low values in transparency and basal area increment of the intermediate and dominated layer. On the other hand, several changes were detected in relation to the chemical and physical status over the period 2003-2005. Some few regularities were identified: (i) change/deviations concentrated on few plots; (ii) high ozone (O3), low sulphur deposition and low precipitation were the attributes more consistently related tochanges/deviations; (iii) most deviations were due to changes in the correlation structure of the attributes; and (iv) there is no consistenttiming of change/deviations among plots. These findings emphasise the need to evaluate the data at the plot level and this indicate the importance of obtaining a time series long enough to enable plot-wise integrated analysis