CONTENTS
 

PREFACE

1

The CONECOFOR Programme: general presentation, aims and co-ordination

Bruno Petriccione and Enrico Pompei

Following EU Regulation no. 1091/94, the Ministry for Agriculture and Forestry Policy (National Forest Service) has since 1995 sponsored the "National Integrated Programme for Forest Ecosystems Monitoring" (CONECOFOR), implemented to study the ef­fects of atmospheric pollution and climate change on forest ecosystems. The Programme also operates within the framework of the Geneva Convention on Trans-boundary air pollution (L.R.T.A.P. U.N.-E.C.E.), ratified by Italy in 1982, and of the Resolutions of the Ministerial Conferences on the protection of forests in Europe (Res. no. 1, Strasbourg, 1990, Res. H4, Helsinki, 1993). The Pro­gramme involves the development of the so-called Level I investigations, which have been in progress since 1987 on a European grid made up of 16×16 km². At present there are in Italy 265 monitoring plots distributed over the whole country, where annual assess­ments are made of the state of the tree crowns. At selected points within the same square, in 1995/6, pedological investigations were carried out and the chemical content of the leaves analysed. The Level II CONECOFOR Programme is currently based on 28 per­manent plots in the framework of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests; 11 areas are also classed as "biomonitoring sites", in the framework of the International Co-operative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems. Nine different researches have since 1996 been in progress in the permanent plots, involving the following analyses: geological and geomorphological (preliminary), vegetation (yearly), crown con­dition (yearly), chemical content of leaves (every 2 years), soil (every 10 years), variations in tree growth (every 5 years), atmos­pheric depositions (continuous), meteorological (continuous), atmospheric pollutants (continuous). Since 2000, surveys of soil solu­tion (continuous), tree phenology (continuous) and ozone visible damage (yearly) have been added. Test phases of new surveys (bio­diversity, biotic damage, etc.) are planned for 2002/3. The National Forestry Service (CONECOFOR Service) co-ordinates six par­ticipating research institutes, each of which is responsible for the analyses and monitoring activities. The permanent plots are se­lected according to the directive of EU Regulation no. 1091/94 so as to include the major forest ecosystems in Italy, and are distrib­uted over the whole country. Each covers an area of 10-100 ha, within which two sample units of 2,500 m² are designated. The main dominant species are Fagus sylvatica (10 areas), Picea abies (6), Quercus cerris (5), Quercus ilex (4), Quercus petraea (1) Quercus robur (1) and Abies alba (1). The first six years of the CONECOFOR Programme have resulted in a detailed, organic description of the main forest ecosystems in Italy. Implementation of the programme has meant that we are now in possession of a reasonably complete knowledge of the ecological characteristics of 17 different Italian forest communities ranging from the Alps to Sicily. The assessment and monitoring of forest health represent a key point for environmental policy-makers and for the management of envi­ronmental resources in the framework of sustainable development.

2

Crown condition assessment at the CONECOFOR Permanent Monitoring Plots

Filippo Bussotti, Alberto Cozzi, Marco Ferretti, Enrico Cenni, Davide Bettini and Renzo Nibbi

A detailed crown condition assessment is currently being carried out at the CONECOFOR (CONtrollo ECOsistemi FORestali, Control of Forest Ecosystems) plots. The assessment began in 1996, and during the first two years (1996 and 1997) an assessment form based on previous regional experience was used; in 1998 the new official EU form was adopted. The resulting loss of compara­bility means that only a few indices can be used in the temporal series 1996-1999. Much effort was devoted to Quality Assurance (QA) procedures. The QA program is structured as follows: (i) specific field manuals have been adopted and are continuously up­dated; (ii) a national training and intercalibration course (NT&IC) is undertaken yearly before beginning the assessment cam­paign;(iii) field checks are carried out yearly on a large number of plots. The results of the QA program have shown that for several indices the quality objectives were not reached, but the quality of the data is improving with time. To express the change in crown conditions in each area, a complex index (CCI = Crown Condition Index) was adopted. This index is the result of the sum of the re­lativized values of all the common indices used during the four years. The following parameters were used: transparency, ramifica­tion type, leaf colour alteration extension, leaf damage extension, alteration of leaf distension extension. The range within which the CCI fluctuates was evaluated taking into account all the observations carried out at a given plot throughout the years. The number of cases over a given threshold (outliers) was calculated for each year. The threshold for outliers was calculated as the median value plus 2 times the range of the interquartile value. All individual cases exceeding this value are considered outliers. The results are presented for all the areas in which the data set is complete for the four years. The yearly fluctuations are discussed and related to possible causes.

3

Survey and assessment of vegetation in the CONECOFOR permanent plots

Bruno PETRICCIONE

Phytosociological knowledge of plant communities and their synecological allocation are the reference basis of the CONECOFOR Programme. Vegetation surveys are performed in all the CONECOFOR plots (28), and have been performed in most of them for 6-7 years, following two fundamental approaches: (1) phytosociological (plant community level) and (2) dynamical (population level). According to a syntaxonomical analysis, 17 plant communities are represented in the CONECOFOR permanent plots, grouped in three classes (Querco-Fagetea, Vaccinio-Piceetea and Quercetea ilicis). Analysis of species richness at community level shows that the total number of vascular species varies between 14 and 81, the lowest values occurring in beech forests and the highest in Turkey oak forests; spruce forests are divided into two groups, the first comprising the secondary type (with high diversity values) and the second comprising the primary type (with relatively low diversity values). Analysis of the main dynamical tendencies show that fluctuation is the commonest ongoing process (occurring mostly in beech and primary spruce forests). Regeneration is also widespread, following the recent general decline of wood exploitation and coppicing, whereas regression and de­generation have been identified only in a few plots. The first vegetation changes seen during the first 6-7 years of investigation are slight and of very low significance. The temporal variation, however, is generally positive, with a fair increase in the number of spe­cies. Further assessment is required to evaluate the ongoing trends.

4

Forest soil conditions in the CONECOFOR Permanent Monitoring Plots and in the Level I Network in Italy

Francesco ALIANIELLO, Francesco A. BIONDI, Cinzia FERRARI, Girolamo MECELLA and Luigi NISINI

The study of forest health is not complete without an assessment of soil condition. Forest soils were monitored in 20 Italian sites in the CONECOFOR programme with different pedological and climatic conditions, the Permanent Monitoring Plots (PMPs). The main objective was the evaluation of the effect of acid depositions on soils and nutrient availability. The FAO classification was ap­plied to all the CONECOFOR soils. Other analyses were carried out on the organic layer and on four mineral layers. Although the number of sites is too small for this monitoring to be considered wholly representative of the state of Italian forest soils, the analyses yield some general information. In addition, a smaller number of determinations were carried out on a higher number of soils (70 soils in the first level monitoring programme (FLP), including the twenty PMPs). Results show that no soils have pH <3 and few soils have pH between 3.0-3.5 (measured in CaCl₂ solution). Furthermore, the soils with low pH values are naturally acid, due to the parent material. The parameters that provide information on the sensitivity of soil to acidification, such as base saturation and the sum of exchangeable base cations in the mineral layers, as well as the amount of total K, Ca and Mg in the organic layer, show that there are hardly any soils in poor health. A high proportion of Italian soils have a lower content of organic matter than other Euro­pean soils, due to Mediterranean climatic conditions; these are very different from those in central and northern Europe, which rep­resent the majority of the European soils monitored. The availability of nutrients (particularly nitrogen and phosphorus) is on the whole sufficient. The results of the determinations of the FLP programme confirm the evaluations expressed for the PMPs, but pro­vide more information, for example regarding the C/N ratio in the different soil layers: several anomalous sites, where the C/N ratio is higher in the surface mineral layer than in the organic layer, were found in this programme, but not in CONECOFOR.

5

Soil conditions under a Fagus sylvatica CONECOFOR stand in Central Italy: an integrated assessment through combined solid phase and solution studies

Guia Cecchini, Stefano Carnicelli, Aldo Mirabella, Francesco Mantelli and Guido Sanesi

As soil solution represents the major phase of soil chemical reactions, its study is a powerful tool for ecological investigations. Soil solution chemical composition gives a realistic idea about the soil chemical components immediately available in the environ­ment, mainly in relation to the soil ecosystem reaction to the disturbance due to acidifying loads. Within the CONECOFOR Program, the monitoring of forest soil conditions was performed in a level II plot (ABR I), under a Fagus sylvatica (European beech) stand, through the study of throughfall and soil solutions collected from depths ranging between the base of the litter layers and 90 cm. To be able to investigate solution contents of nutrients, acidifying agents and DOC throughout the profile, both zero tension and tension lysimeters were used. The first ones were inserted below the organic horizons, while tension lysimeters were placed within the min­eral horizons at 15, 25, 55 and 90 cm depth. Sampled solutions were analyzed for Na, K, Ca, Mg, NH₄, Cl, F, NO₃, SO₄, and DOC. The results evidence a clear seasonal pattern, mainly for macronutrients and inorganic N components. Acidic pulses were mostly evident below the organic horizons, in relation to strong nitric N releases from litter; these last were not always immediately neu­tralized by basic cations. Acid solutions leaving the organic horizons were invariably neutralized in the surface mineral horizons, within 15 cm depth. Temporal patterns of sulphate retention and release suggest that the soil has low retention capability for this anion. Such behaviour can be explained by the composition of the solid phase, where potential anion adsorbants appear strongly linked with organic matter in long residence time complexes. Sulphate and nitrate loading of this soil appear, anyway, to be mostly non-anthropogenic, but rather linked to natural mineralization pulses and, for sulphate, to aeolian solid transport from the south.

6

Contribution to growth and increment analysis on the Italian CONECOFOR Level II Network

Gianfranco FABBIO and Emilio AMORINI

The paper deals with the "Estimation of growth and yield" included in the National Programme on Intensive Monitoring of For­est Ecosystems CONECOFOR Aims of the paper are: i) to outline the composition and design of Level II PMPs network, also ex­amining the structural characteristics of forest stands; ii) to describe the contents of mensurational surveys carried out in winter 1996/97 and 1999/00; iii) to analyse the growth rates in progress at each PMP using selected descriptors. Stand origin (11 high for­ests and 13 stored coppices and transitory crops) and the number of forest types tested are focused as the main discriminants of the PMPs network. This composition, together with irregular forestry practice, results in a number of consequences (prevailing age classes, tree densities and related stand structures, growth patterns) which cause a high in-and-between variability of all growth pa­rameters. For the purposes of this analysis, the network of the plots was divided into three main sets: broadleaved high forest (i.e. beech stands), 6 PMPs; coniferous forest (i.e. Norway spruce stands), 5 PMPs; coppice forest (i.e. deciduous and evergreen oaks, beech and hardbeam stands), 13 PMPs. The measurement of basic growth variables (dbh and tree height) was used to describe the tree populations in each PMP; the calculation of basal area, mean and top dbh, mean and top height, provided the reference dataset at each inventory. The assessment of social class according to Kraft gave information on vertical stand structure and made it possi­ble to analyse growth according to tree layers. Data comparison provided increments in the interval 1997-2000. The occurrence of natural mortality and ingrowth was also assessed to take into account their combined effect on tree population dynamics. No trend was found, due to limited data availability, but it was possible to have a detailed overview of the stand situation and growth rates in PMPs

7

Tree ring growth by core sampling at the CONECOFOR Permanent Monitoring Plots. The deciduous oak (Quercus cerris L.) type

Maria Chiara MANETTI

Radial growth analysis evaluates the ability of trees to grow under different site and environmental conditions, thus contributing to bio-ecological studies aimed at increasing understanding of forest stand evolution. Tree ring growth is analysed in five Permanent Monitoring Plots (PMPs) dominated by Turkey oak (Quercus cerris L.). Common structural features of these PMPs are their origin (coppice forest) and their current physiognomy as stored coppice and transitory crop. A dendroecological approach was used to analyse past radial stem growth, the influence of silvicultural background and stand age, as well as to compare the growth rhythm of stands in different site-indexes and environmental conditions. Tree coring was carried out at the time of the first inventory (winter 1996/97) by sampling 8 to 11 dominant and co-dominant trees representative of the upper storey in the buffer area of each PMP. The basic stem and crown growth variables were measured for each tree sampled and two cores collected at 1.30 m. Annual ring width was determined by the Tree Ring Measurement System SMIL3 and the data were elaborated by the ANAFUS software. Site mean curves and growth trend per social class in each stand were defined both by visual comparison and statistical analysis among indi­vidual tree series. The main results were as follows: i) social differentiation becomes established earlier with better site indexes and higher tree densities; ii) sensitivity to external disturbances is higher and more defined in the dominant class than in the co-dominant tree layer; iii) competition cycles are clearly discernible and related to both stand density and site-index in young stands under natu­ral evolution (stored coppices); iv) when silvicultural interventions were performed in the past is quite visible readable in the stands under conversion into high forest (transitory crops); v) the mean series per site are statistically related and common periods char­acterized by a similar growth trend have been recognized.

8

Litterfall and Leaf Area Index in the CONECOFOR Permanent Monitoring Plots

Andrea CUTINI

Forest canopies are more sensitive and react more promptly to abiotic and biotic disturbances than other stand structural com­ponents. Monitoring crown and canopy characteristics is therefore a crucial issue for intensive and continuous monitoring programs of forest ecosystem status. These observations formed the basis for the measurement of annual litter production and leaf area index (LAI) in the Italian permanent monitoring plots (CONECOFOR program) established within the EC-UN/ECE program "Intensive Monitoring (Level II) of Forest Ecosystems". Preliminary results after three years of observation are presented. The low value of within plot mean relative standard deviation (20.8 ± 1.9%) of litter production, which in any case never exceeded 30%, accounted for the good sampling error and accuracy of the chosen method, which seems to be accurate enough to detect changes in litter pro­duction through the years. The higher inconsistency of the amount of woody and fruits fractions over the years demonstrated the greater reliability of leaf fraction or, on the other hand, of LAI compared to total litter. Mean values of annual leaf-litter and total litter production and LAI were rather high in comparison with data reported in literature for similar stands, and reflected both a medium-high productivity and a juvenile phase in the development of the selected stands on average. Focusing on changes in litter production through the years, statistical analysis on a sub-sample of plots showed the existence of significant differences both in leaf litter and total litter production. These findings seem to attribute to the "year" factor a driving role in determining changes in litter production and LAI. Temporal intermittence in data collection, together with the shortness of the monitoring period, make it difficult to speculate or arrive at definitive conclusions on changes in litter production due to time-dependent factors. The importance of having a complete database to increase index representativeness and reliability and, on the other hand, of performing an integrated results analysis which takes into account the outcomes of other research actions, is recognized as an indispensable requirement for achieving the goals of the monitoring program.

9

Ozone and nitrogen dioxide measurements in the framework of the National Integrated Programme for the Control of Forest Ecosystems (CONECOFOR)

Armando Buffoni

Ozone (O₃) concentrations were monitored using passive (diffusive) samplers at 20 permanent monitoring plots of the National Integrated Programme for Forest Ecosystem Monitoring (CONECOFOR) during late spring and summer from 1996 to 2000. Nitrogen dioxide (NO₂) concentrations were measured at the same sites with passive samplers during the same months in 1999 and 2000. Measurement devices were placed at a short distance from the forest plots in areas with freely circulating air. The exposure period for O₃ passive samplers was 1 week; NO₂ samplers were exposed for 7 days in 1999 and 14 days in 2000. Mean O₃ con­centrations recorded by the passive samplers for the monitoring periods in individual years vary from 75.2 to 125.8 µg m^-3, showing considerable differences between individual years and the geographical locations of the monitoring sites. Generally speaking O₃ concentration levels are higher at the plots located in Central and Southern Italy. The highest mean weekly concentrations were re­corded in Sicily with a maximum of 171 µg m^-3. No correlation can be found between O₃ levels and elevation if all the plots are con­sidered, while a significant increase of O₃ levels with elevation can be observed in the six plots located in the Alpine region. The cor­relation analysis of 5-year mean concentration data and plot latitude show a moderately close relationship. Mean weekly concentra­tions often exceed 65 µg m^-3 as 24 h mean, one of the short term thresholds proposed for the protection of vegetation. Exceedances are recorded in all monitoring periods. At the permanent monitoring observation plot in Sicily this threshold was exceeded in all the years of the study. Mean weekly or fortnightly NO₂ concentration levels are generally very low, with the exception of some plots in­fluenced by nearby emissions or transport phenomena. NO₂ probably exceeds the critical level for the protection of forest ecosystems at one plot only. No correlation was observed between NO₂ and O₃ concentration data.

10

The chemistry of atmospheric deposition in Italy in the framework of the National Programme for Forest Ecosystems Control (CONECOFOR)

Rosario MOSELLO, Maria Cristina BRIZZIO, Dimitrios KOTZIAS, Aldo MARCHETTO, Diana REMBGES and Gabriele TARTARI

Under the CONECOFOR programme, allied to the UE and UN-ECE programme on forests (ICP Forests), the chemistry of open field, throughfall and stemflow deposition was measured in 15 permanent plots over a two year period. Characteristics of the plots, sampling methods, treatment and analyses are in strict agreement with those adopted in the European programme. The plots are representative of different geographical conditions, from the Mediterranean area of the southern plots to the Alpine environment. Results show the highest amount of ion deposition related to anthropogenic emissions in the northern (PIE1, VEN1, FRI2) and cen­tral (EMI1, TOS1) stations, while most of the central and southern sites show a net flux of alkalinity. The acidity is however buffered by dust and dry deposition present on the canopy, so that the throughfall deposition is always alkaline. Nitrogen, both as ammonium and nitrate, is an important component of precipitation and critical loads are exceeded in most of the areas. This situation is con­firmed by analyses of nitrate in runoff, performed in four plots, which show a release from the watershed in all seasons, indicating an overload of nitrogen compared to its possible uptake by vegetation and soil. N saturation is high in the northern and central plots of PIE1 and EMI2, moderate in the central and alpine plots of LAZ1 and FRI2.

11

Meteorological monitoring and climatological trends in Italian forest ecosystems

Tiziana AMORIELLO and Andrea COSTANTINI

In the framework of long term ecological research on Italian forests, this paper describes meteorological monitoring in Italy, analysing meteorological trends in the CONECOFOR areas, paying particular attention to temperature, solar radiation, precipita­tion and windiness. The correlation between geomorphologic and climatic conditions is also examined and the areas characterised climatically through the Thornthwaite model. The analysis is based on measurements performed for the last five years at Open Field and In the Plot stations. This study may help to understand the effects of a microclimate, taking into account its possible impact on crown

12

Management of forest vegetation data series: the role of database in the frame of Quality Assurance procedure

Roberto CANULLO, Giandiego CAMPETELLA, Maria-Cristina ALLEGRINI and Vincenzo SMARGIASSI

If data from diachronic records on permanent areas are to be made available, the quality of the historic sequences must be stan­dardised, preserved, organised and checked in such a way as to permit continuous input and comparison. The "Ground Vegetation Assessment" group of the CONECOFOR programme designed a database with extended search capability to ensure rapid and pre­cise access to data. The vegetation is analysed within a network of permanent plots, based on field surveys conducted at community and population level. Assessments include specific, stratified and overall cover estimates as well as detailed cover scores and density of aboveground shoots (respectively on 24 100 m² and 100 0.25 m² sampling units). In addition to archiving data, the database runs functions to check their validity. The integrity of the dataset and its conformation to the user defined range can be assessed, and the entire sequence can be validated before the new data is saved in the database. Subsequent cross-checks among attributes allow fur­ther tests of validity and precision. These functions are an integral part of the overall Quality Assurance Control system. The data are organised into seasonal surveys, plots and sampling units. Each species has a field code, with reference to a second archive of coded nomenclature established at a European level. A section for addition and deletion of data makes output available according to the appropriate EC regulations. The system guarantees the visualisation of a certain number of simple statistics, and also permits export of analytic data to external statistical tools.

13

The Integrated and Combined (I&C) evaluation system to detect status and trends of the CONECOFOR Permanent Monitoring Plots

Marco FERRETTI

CONECOFOR is the Italian program for the intensive monitoring of forest ecosystems sponsored by the Ministry for Agricul­tural and Forest Policy and the European Commission. It is based upon a series of investigations carried out on 20 (27 from 1999) plots located throughout Italy. The investigations collect data on various ecosystem compartments (soil, ground vegetation, trees, atmosphere) and processes (atmospheric inputs, tree nutrition and growth). A major benefit of intensive monitoring programs is the opportunity they provide to organize integrated studies aimed at understanding the driving forces acting at the ecosystem level. In Italy, the Integrated and Combined (I&C) evaluation system within the CONECOFOR program involves three major approaches: (i) the evaluation of risk status in relation to air pollution, (ii) the quantification of the ecosystem’s status and changes, and (iii) the evaluation of the relationship between pressure and status indicators through time. The I&C project involves scientists from many institutions; major emphasis is placed on the evaluation of data quality and precision. These are regarded as the basic steps in the whole project and a likely source of information about the suitability of the current sample sizes for providing a proper estimation of the parameters under consideration. The paper will provide information on the conceptual and methodological background of the I&C project

14

Forest condition and chemical characteristics of atmospheric depositions: research and monitoring network in Lombardy

Raffaella BALESTRINI, Antonio TAGLIAFERRI, Gianni TARTARI and Flaminio DI GIROLAMO

Since 1987, the Regional Forestry Board of Lombardy and the Water Research Institute of the National Research Council have been carrying out surveys of forest conditions and the response of the ecosystem to environmental factors. The study approach is based on a large number of permanent plots for extensive monitoring (Level 1). At this level, crown condition is assessed annually, and soil condition and the nutritional status of forests surveyed. Some of the permanent plots were selected for intensive monitoring (Level 2), focussing mainly on the impact of atmospheric pollution on forest ecosystems. Level 2 monitoring also includes increment analyses, ground vegetation assessment, atmospheric deposition, soil solution analyses and climatic observations. This paper sum­marises the main results of a pluriannual research, which provides a general picture of the state of forest health in the region and fo­cuses on more detailed investigations, described as case studies. Modified wet and dry samplers which use a water surface to collect dry deposition were used in a pluriannual field campaign at five sites in alpine and prealpine areas, to measure the total atmospheric depositions and to evaluate the nitrogen and sulphate exceedances of critical loads. Throughfall and bulk precipitation chemistry were studied for five years (June 1994-May 1999) at two high elevation forest sites (Val Gerola and Val Masino) which were known to differ in terms of tree health, as assessed by live crown condition. Results indicated a higher contribution from the dry deposition of N-NO₃^-, N-NH₄⁺ and H⁺ and considerable canopy leaching of Ca²⁺, K⁺ and weak organic acids at Val Gerola, where the symp­toms of damage were more evident. In the area of Val Masino (SO), included since 1997 in the national CONECOFOR network, investigations focused on the effectiveness of the biological compartment in modifying fluxes of atmospheric elements, and on the role of nitrogen both as an acidifying element and as a nutrient. To estimate the input-output budget of the catchment, monitoring was extended to stream water and soil solution.

15

Forest ecosystem monitoring in Tuscany (Italy): past activities, present status and future perspectives

Luigi Bartolozzi, Ilaria Bonini, Renzo Boretti, Filippo Bussotti, Enrico Cenni, Alessandro Chiarucci, Alberto Cozzi, Vincenzo De Dominicis, Marco Ferretti, Paolo Grossoni, Gianluca Landi, Claudio Leonzio and Giovanni Vignozzi

Since 1987 the Region of Tuscany has been actively monitoring crown status in its forests, in order to protect them from atmos­pheric pollution, biotic factors and environmental change. Over this period the Region has performed periodical inventories on crown condition in publicly-owned forests (Level I network) and established a network of permanent plots (MON.I.TO., Level II – III) to study long-term changes occurring in forest ecosystems. Some of these permanent plots were later included in the national programme CONECOFOR, managed by the Ministry for Policy in Agriculture and Forest. Currently a further development of MON.I.TO. is being implemented, called MONITO III – TOpModel, the aim of which is to broaden the information potential of the monitoring system to include carbon stocks and biodiversity evaluation. This paper provides an up-to-date report on the status of the various surveys and recommends a closer connection between MON.I.TO. and the other regional information systems, especially the Regional Forest Inventory, in order to produce information that may be useful in forest planning and in Sustainable Forest Manage­ment.

16

Eight years of integrated monitoring in Alpine forest ecosystems of Trentino and South Tyrol, Italy

Paolo AMBROSI, Andrea BERTAGNOLLI, Mauro CONFALONIERI, Nicola LA PORTA, Flavio MARCHETTI, Giorgio MARESI, Stefano MINERBI, Cristina SALVADORI and Ruggero VALENTINOTTI

After the acute emergency of decline in European woodland at the beginning of 1980’s, forest health was the subject of several studies in Trentino and South-Tyrol. Since 1992 investigations focused on an integrated monitoring under the UN-ECE-ICP pro­gramme in 4 selected areas, 2 in subalpine Norway spruce woodland (Lavazè Pass and Renon), and 2 in thermophilous Pubescent oak woodland (Pomarolo and Monticolo). The interdisciplinary programme of integrated monitoring aimed to investigate the state of alpine semi-natural forests in relation to air pollution, anthropogenic stresses, climate changes and trophic-energetic balances. As­sessment of forest health by means of crown conditions showed very low levels of defoliation and discoloration in the subalpine ar­eas, while in the other ones the same parameters had slightly higher values. Every year and in all the sites the mean percentages val­ues were always in class 0 and class 1, hence indicating no danger. Weather patterns showed the presence of occasional water defi­cit, albeit general trends were not observed. High level of pollution were never detected while the level of acidity in rainfall has been slightly decreasing in all the investigated plots. Only ozone showed higher values than normal but there was no correlation with any damage. Foliar mineral nutrient contents ranged quite always within the threshold level. Because of the few years of observation and the absence of relevant stress, it is not possible to get any indication about the relationship between the forest health status and the fungi community composition. The presence of some anomalous data and the growing concern on climate change give reason to the importance of a continuous monitoring action acquiring of comparable set of data, in order to get a better understanding of forest ecosystems response to stress and make progress in general ecological knowledge.

17

Atmospheric deposition at four forestry sites in the Alpine Region of Trentino-South Tyrol, Italy

Flavio MARCHETTI, Danilo TAIT, Paolo AMBROSI and Stefano MINERBI

The Trentino-South Tyrol Region is located in the southern part of the Alpine Chain. The territory is largely mountainous with crystalline rock formations dominant in the north and limestone in the south-east. Most of the land is open to the climatic and at­mospheric influence of the River Po, via the mainly N-S oriented valley of the River Adige. The forestry authorities of the region have since the 80s been making an annual assessment of forest decline, particularly as regards parasite attacks, defoliation and crown discoloration, and have found the situation to be better than in most other parts of Europe. The region's forest protection policy is administered by the two provinces of Bolzano/Bozen and Trento in the framework of the European convention on Long Range Transboundary Air Pollution (UN-ECE LRTAP); each province operates two forestry sampling permanent plots. The sites are all constituted according to the standard recommendations, and are located in the central part of the region along the Adige Valley, where most of population live and where most of the agriculture and industry is. Two of the areas are in coniferous stands of the typical Alpine forest, mainly composed of Norway spruce; the other two are located in deciduous stands (both high forest and cop­pice) and are closer to the urban centres than the first two. Concentration and deposition values for the main ionic components in bulk, wet, throughfall, stemflow and soil water are given separately for the four monitoring sites, with reference to the period 1996-1999. The major acidifying component in atmospheric precipitation is still sulphate, but as other investigations confirm, the relative importance of the nitrate input is increasing all the time. The effect of these changes is probably positive for terrestrial ecosystems in the short term because of the decrease in total acidifying input and the increase in inorganic fertilisation. The absence of major "for­est" damage, outlined in the annual forest damage survey reports issued by the forestry authorities (internal reports since 1983), suggests that the current atmospheric acidic load is in balance with the stational and climatic conditions.

18

Long-term ecological research on Italian forest ecosystems: perspectives and conclusions

Rosario Mosello, Bruno Petriccione and Aldo Marchetto

The paper summarises the contents of the present volume devoted to forest research in Italy, within the National Programme for Forest Ecosystem Monitoring (CONECOFOR), part of the Level II forest monitoring, and other linked regional and provincial monitoring activities. The coordination of the project, through a National Focal Centre and a Task Force for the Integrated and Combined Evaluation of results, made up of the foremost Italian experts working in the field, is outlined. No clear signals of strong negative impacts emerge from the papers, although the results of several studies indicate nitrogen and ozone as possible causes of disturbances in a number of plots. The effects of the deposition of acidity are largely buffered by the nature of the soils, while nitrate is leached from the plots where runoff is analysed, indicating N saturation of soils. This paper describes the main activities of the Task Force as regards data validation and elaboration, aimed at providing reliable information leading to sustainable forest man­agement in Italy as well as making a useful contribution to international activities in a Pan-European context.