Windstorm disturbance triggers multiple species invasion in an urban Mediterranean forest

Plant invasion in forest ecosystems is a serious ecological and economic issue, deserving attention by researchers, managers and policy-makers worldwide. Many invasive plants have been reported as early successional species able to colonize disturbed areas following abrupt changes in microhabitat and resource availability. We investigated disturbance effects of a severe windstorm generated by a wet microburst (hail and rain at 160 mm h-1) remarkably affecting the canopy cover of an old-growth Quercus ilex urban forest in Southern Italy. This stand-replacing disturbance produced a mosaic of 103 gaps, 5.6 to 1632 m2 in size, over an area of 1.53 ha, uprooting 76% of the trees and decreasing thereby 85% of the standing above-ground dry biomass into the gaps. By intensive monitoring we compared above- and below-ground microclimate, soil moisture and mineral N availability in paired disturbed and control areas of the study forest. Within newly formed gaps we observed a seasonally consistent 70% higher content of nitrate nitrogen, 29% and 47% decreases of ammonia nitrogen in summer and autumn, respectively, and a higher moisture in topsoil, in addition to different above- and below-ground microclimatic conditions, with canopy cover mitigating extreme temperatures. One year after the windstorm, the microhabitat shift promoted the establishment in gaps of 15 native and 10 alien taxa previously absent in both disturbed and control plots. In such conditions, the rarefaction of the dominant Q. ilex canopy cover and the occurrence of empty niches prone to invasion could dramatically affect the local community structure and diversity. Our data indicate that stand-replacing windstorm can transiently transform the studied urban evergreen forest to an early allogenic successional community dominated, in the medium and large gaps, by annual and perennial non-native species. This is particularly relevant under a perspective of possible increasing frequency of windstorm events in the Mediterranean region in the near future

The Changes in China's Forests: An Analysis Using the Forest Identity

Changes in forest carbon stocks are a determinant of the regional carbon budget. In the past several decades, China has experienced a pronounced increase in forest area and density. However, few comprehensive analyses have been conducted. In this study, we employed the Forest Identity concept to evaluate the changing status of China's forests over the past three decades, using national forest inventory data of five periods (1977–1981, 1984–1988, 1989–1993, 1994–1998, and 1999–2003). The results showed that forest area and growing stock density increased by 0.51% and 0.44% annually over the past three decades, while the conversion ratio of forest biomass to growing stock declined by 0.10% annually. These developments resulted in a net annual increase of 0.85% in forest carbon sequestration, which is equivalent to a net biomass carbon uptake of 43.8 Tg per year (1 Tg = 1012 g). This increase can be attributed to the national reforestation/afforestation programs, environmentally enhanced forest growth and economic development as indicated by the average gross domestic product

The late Holocene history of cypress (Cupressus sempervirens L.) in the Italian peninsula: New perspectives from archaeobotanical data

The objective of this research is to reconstruct the recent Holocene history of Cupressus sempervirens from the Bronze to the Roman Age in Italy. Our work consisted both in a review of published data and in the identification of novel archaeobotanical remains stored in the deposits of the National Archaeological Museum of Naples and of the Archaeological Park of Pompeii. The literature permitted to collect information linked to different plant remain typologies of the Italian cypress; 362 botanical remains were counted, of which 292 were from the Vesuvian area and 70 from other archaeological sites of the central and western Mediterranean. Data chronology spans from the second century BC to the AD fifth century for the archaeological area of ancient Campania and from the 14th century BC to the AD fourth century for the sites located in different regions. It is clear that the ‘cypress culture’ is confirmed by the archaeobotanical data found in the Roman world. Romans especially appreciated its timber but cypress was also used for many other purposes. Furthermore, the employment of timber for wells was documented in pre-Roman sites and the presence of fruits/seeds in central Italy confirms its importance also in the Bronze Age

Generalized functions of biomass expansion factors for conifers and broadleaved by stand age, growing stock and site index

Parties to the Kyoto Protocol and/or the United Nations Framework Convention on Climate Change (UNFCCC) are required to account for their direct human-induced carbon emissions and removals including those from forestry and other land use related activities. In most European countries, the forestry related greenhouse gas inventories are largely or exclusively based on converting tree volume data from national forest inventories to biomass using biomass conversion and expansion factors (BCEFs). However, country specific data for many species are often lacking, which considerably increases the uncertainties of the greenhouse gas inventories. The focus of this research was to develop, using internationally published datasets that cover a large geographical area, an extended set of generalized curves of such biomass expansion factors for several species or species groups by age, growing stock and site index. (C) 2008 Elsevier B.V. All rights reserved

Utilizzazione di dati inventariali a scala aziendale e dati LiDAR per la stima delle variazioni temporali dello stock di carbonio epigeo nel demanio forestale di Vitulano (BN, Campania)

La rendicontazione dello stock di carbonio di un bosco e la stima temporale delle sue variazioni rappresenta una nuova occasione professionale per chi opera nel settore forestale. La mancanza di dati inventariali a scala locale (aziendale), la loro disomogeneità e l'eterogeneità strutturale degli ecosistemi forestali mediterranei può rende inaccurata e/o imprecisa la stima temporale delle variazioni degli stock di carbonio quando viene effettuata con metodologie esistenti (UNFCCC 2003, UNFCCC 2006). L'utilizzo di nuove tecniche di analisi del territorio (ad es., voli LiDAR) permette l'integrazione con i dati comunemente acquisiti nell???ambito della compilazione del piano di assestamento forestale (PAF) e consente di verificare l???accuratezza o la precisione delle stime effettuate a partire da dati LiDAR. Una verifica di questo tipo è stata eseguita utilizzando scansioni laser (LiDAR) da aereo acquisite nell???ambito del progetto LIFE SOILCONS-WEB e dati provvigionali del demanio forestale del comune di Vitulano (BN) relativi al 2003, anno di redazione del PAF, opportunamente aggiornati al 2011. Si riportano in questo lavoro le linee metodologiche applicate per la stima delle variazioni temporali di carbonio a scala locale, la loro verifica tramite analisi LiDAR, nonché i limiti applicativi riscontrati nell'utilizzo di metodologie sviluppate per inventari a scala regionale e/o nazionale con dati raccolti per fini gestionali a scala locale

Recent history, use and forgetfulness of the cypress forest of fontegreca (Southern Italy)

The cypress (Cupressus sempervirens) is characterized by a very ancient history linked to the wide employment for the technological properties of its wood and for its symbolic value. Although this tree was often considered as a species introduced in Italy, the first genetic studies showed, instead, the presence of an autochthonous population of C. sempervirens in the forest of Fontegreca (Matese massif, Southern Italy), which constitutes the unique autochthonous cypress woodland present in Southwestern and Western Europe. Therefore, investigations were carried out in selected (using geomorphological criteria) areas of the forest, through soil chemical analysis, identification and 14C dating of soil charcoals. Indeed, we hypothesize that these analyses allow clarifying the history of this woodland characterized by the dominance of the cypress in the forest cover. Areas at medium-low (17–29◦) slope gradient on the eastern and southern slopes of the forest were investigated and sampled, following pedological criteria (soil horizons order). Soil morphological and chemical analysis showed humus-rich surface horizons, thin (15–30 cm) and poorly developed (young) soils, overlapping the bedrock limestones. The first soil charcoal analysis data highlighted the presence of a previous landscape characterized by several species (e.g., Pistacia, Ostrya carpinifolia, Juniperus sp. and Pinus sp.) and, probably, by a different forest structure. Ongoing charcoal identification and 14C dating will likely give a better understanding of both (1) the cypress history and (2) the development of this forest landscape

Developing an accurate and fast non-destructive single leaf area model for loquat (Eriobotrya japonica lindl) cultivars

In this research, seven different models to predict leaf area (LA) of loquat (Eriobotrya japonica Lindl) were tested and evaluated. This species was chosen due to the relevant importance of its fruit as an appreciated early summer product and of its leaves and flower as a source of additional income within the nutraceutical and functional food markets. The analysis (calibration and validation) was made using a large dataset (2190) of leaf width (W), leaf length (L), and single LA collected in ten common loquat cultivars. During the analysis, the results obtained using one- and two-regressor models were also evaluated to assess the need for fast measurements against different levels of accuracy achieved during the final estimate. The analysis permitted to finally select two different models: 1) a model based on a single measurement and quadratic relationship between the single LA and W (R2 = 0.894; root mean squared error [RMSE] = 12.98) and another model 2) based, instead, on two measurements (L and W), and on the linear relationship between single LA and the product of L × W (R2 = 0.980; RMSE = 5.61). Both models were finally validated with an independent dataset (cultivar 'Tanaka') confirming the quality of fitting and accuracy already observed during the calibration phase. The analysis permitted to select two different models to be used according to the aims and accuracy required by the analysis. One, based on a single-regressor quadratic model and W (rather than L) as a proxy variable, is capable of obtaining a good quality of fitting of the single LA of loquat cultivars (R2 = 0.894; RMSE = 12.98), whereas, the other, a linear two-regressor (i.e., W and L) model, permitted to achieve the highest prediction (R2 = 0.980; RMSE = 5.61) of the observed variable, but double the time required for leaf measurement