The umbric epipedon in the N Apennines,Italy—an example from the Vallombrosa Forest

The umbric epipedon is a diagnostic surface horizon recognized by both the World Reference Base for Soil Resources and the U.S. Soil Taxonomy. It is mainly characterized by a dark color, a moderate to high content of OM, and a base saturation of less than 50%. In the N Apennines, Central Italy, forest soils over 600–700 m a.s.l. often have this epipedon. This paper stresses the morphological, chemical, and biological properties of the epipedon, specifically in the Vallombrosa Forest, where considerable work has been done in the last decade. Here, the umbric epipedon forms on sandstone, in high forests of Abies alba, Fagus sylvatica, and Castanea sativa. It does not have homogeneous properties throughout its thickness and often is divided into two distinct genetic horizons, A1 and A2. The A1 horizon is thinner, darker, and richer in OM, more base‐saturated, and biologically more active than the underlying A2 horizon. The mean residence time of the bulk OM amounts to about a century in the A1 horizon, versus half a millennium in the A2. In both A1 and A2 horizons, the non‐humic fraction prevails in the OM; this could account for the high susceptibility of the umbric epipedon to degrade when the forest is clear‐cut or undergoes extensive uprooting due to windstorms or heavy snow loads. Significant discrepancies between the two A horizons have been found in regard to the microbial community. Umbric epipedons which developed under different tree species show minor differences, mainly concerning the microbial community.     

Effect of drainage conditions on winter wheat production

To forecast the suitability of land for winter wheat, soil investigations were directed towards the evaluation of the effect of drainage conditions on productivity. Experiments were carried out on two soil types in Mugello (Italy): a well-drained soil and a poorly drained soil. Measurements of plants, atmosphere and water-table data were taken to simulate soil water contents and yields according to the model of Feddes et al. (1978). Computed and measured soil water contents and yields showed good agreement. On the poorly drained soil, root development was limited by the groundwater table and the final productivity, expressed as dry biomass, resulted in a 50% yield depression compared with that on the well drained soil.     

Benefits and well-being perceived by people visiting green spaces in periods of heat stress

In urban environments, green spaces have proven to act as ameliorating factors of some climatic features related to heat stress, reducing their effects and providing comfortable outdoor settings for people. In addition, green spaces have demonstrated greater capacity, compared with built-up areas, for promoting human health and well-being. In this paper, we present results of a study conducted in Italy and the UK with the general goal to contribute to the theoretical and empirical rationale for linking green spaces with well-being in urban environments. Specifically, the study focused on the physical and psychological benefits and the general well-being associated with the use of green spaces on people when heat stress episodes are more likely to occur. A questionnaire was set up and administered to users of selected green spaces in Italy and the UK (n=800). Results indicate that longer and frequent visits of green spaces generate significant improvements of the perceived benefits and well-being among users. These results are consistent with the idea that the use of green spaces could alleviate the perception of thermal discomfort during periods of heat stress.     

Structural diversity and height growth models in urban forest plantations: A case-study in northern Italy

Current knowledge on the growth models of urban forest plantations several years after their establishment still remains poor and fragmentary. Furthermore few studies have assessed the growth of urban plantations on reclaimed land, such as brownfield sites.This paper assesses urban forest plantations in terms of tree height growth, crown width and vertical structural using as a case study tree inventory-data collected in an urban forest plantation (Parco Nord Milano, PNM northern Italy). In this research tree inventory-data was used to achieve the following objectives: (i) to develop a series of tree height-growth models and tree crown-width models for the main taxonomic units in the study-area; (ii) to analyse the temporal pattern of current increments of tree height; (iii) to assess the vertical stratification of tree crowns using a method developed by Latham et al. (1998).The results suggest that during the earlier stage after planting, trees reach high levels of growth (tree height and crown width) regardless of the taxonomic unit. Evidence is found to support a high level of spatial competition between individual trees of different taxonomic units in as little as 15–18 years. Competition between trees appears to be mainly affected by diametrical differentiation rather than hypsometric variation: trees grow more in diameter than in height. Furthermore a decrease in longitudinal growth was observed for most tree species while the radial growth tends to be constant over time. The research at PNM shows that in temperate climates this can be achieved in less than 30 years. We believe that these analyses could provide important data supporting the planning of new urban forest plantations on reclaimed land and inter alia provide some answers to the questions around plantations growth evaluation and management.     

Carbon dioxide efflux and concentrations in two soils under temperate forests

The carbon dioxide efflux to the atmosphere and the concentrations at various depths in two soils were measured, for more than a year, under pure stands of silver fir ( Abies alba Mill.) and European beech ( Fagus sylvatica L.) in central Italy. Microbial biomass and activity at the monitored depths were determined in the laboratory and the CO₂ evolved from incubated samples was submitted to radiocarbon analysis to assess the mean residence time of the organic matter degraded by microorganisms. The CO₂ efflux showed similar trends in the two soils, with highest values in October and lowest in January. The efflux depended more on air and soil temperatures than soil moisture, and was related to these variables better under fir than under beech. In both soils, the CO₂ concentration increased with depth: in the top horizon it was low and similar to that of the atmosphere, while in the deeper horizons it often amounted to considerable values (up to more than 1% by volume in the BC horizon under fir). The subsoil of the fir stand generally showed much higher CO₂ concentrations than that of the beech. The basal respiration as determined in the laboratory was at a maximum in the topsoil and decreased sharply downwards. Therefore, the high CO₂ concentrations measured in the field at the bottom of the profiles--where roots were few, and microbial biomass and available C pool were at a minimum--appeared to be due more to slow diffusivity of the soil matrix rather than to heavy release of the gas by the biota. The organic matter respired by microorganisms in incubated soil samples showed positive values of j¹⁴C that revealed a recent synthesis. The estimated mean residence time increased with depth, suggesting a generally higher degree of stabilisation of the organic pool in the subsoil.     

Residents and urban green spaces: The case of Bari

The total area of public green spaces in the city of Bari, Italy is more limited than in most other Italian cities (2.9 m²/inhabitant). This fact makes it an interesting subject for research into the general perception that the residents of the city have of green spaces and their behaviour patterns when using them.

A questionnaire (27 questions) was presented by telephone to a representative sample (n=351) of the population of Bari. The aims of the study were: (a) to gain insight in the perception of green spaces with particular reference to those green areas within the city itself; (b) to examine behaviour during visits to parks and gardens and means of transport used to reach them; (c) to investigate what kind of relationship should be set up between the local authority and the population regarding information and participation.

The results show that respondents perceive the green areas as a life quality enhancer in accordance with some previous studies carried out in Italy and in other countries. Citizens are moreover conscious of the limitations in quality and quantity of green areas in their own city, although this result needs to be more closely analysed in the future. Patterns in the use of public green areas proved to be strictly connected with age, sex, marital status, area of residence. Another conditioning factor was the system of mobility. The results moreover underline how citizens see the public and private green areas as single beneficial system.

The research also demonstrates the potentials of applying telephone surveys in studies concerning urban forests.     

Soil moisture regimes and credibility in the assessment of soil suitability for crops in Tuscany

Abstract. Results of recent research on moisture regimes of surface water soils and on soil credibility are summarized, and proposals are made for the use of results in soil evaluation for selected crops.
Measurements of water table depth show high variability from year to year and during the same season. Soil moisture regimes seem to affect soil management more than crop yield. A probabilistic calendar is needed for the occurrence of topsoil moisture content near the lower plastic limit in periods corresponding to the most important management practices. This is required in order to assess important soil qualities like workability and trafficability.
Soil erosion is greatest when superficial run-off can create rills. This happens when run-off shear stresses exceed a threshold proportional to soil shear strength. Consequently, soil shear strength can be used as a measure of soil resistance to erosion. Probabilistic calendars are needed on the occurrence of heavy rainstorms able to create rills when the soil is most at risk.
Entries for ratings of workability, trafficability and erosion risk are outlined.