Search results for " forest"
showing 10 items of 1940 documents
Patterns of earthworm, enchytraeid and nematode diversity and community structure in urban soils of different ages
2016
Annelids (Lumbricidae and Enchytraeidae) and nematodes are common soil organisms and play important roles in organic matter decomposition, nutrient cycling and creation of soil structure and porosity. However, these three groups have rarely been studied together and only few studies exist for urban soils. We studied the diversity and community composition of annelids and nematodes in soils spanning more than two centuries of urban soil development in Neuchâtel (Switzerland) and assessed the relationships 1) among these three groups and 2) between each group and environmental (physical, chemical and functional) characteristics of soils and soil age. While the groups of environmental variable…
Effect of Cd-containing wood ash on the microflora of coniferous forest humus
2000
The use of wood ash in forestry has been questioned because the cadmium (Cd) concentration of ash, which varies between 1 and 20 mg kg(-1) ash, exceeds the level allowed for fertilizers (3 mg kg(-1)) used in agriculture. To investigate the combined and separated effects of Cd and ash on the forest humus microflora, pumice or wood ash, spiked with a water-soluble (CdCl(2)) or -insoluble (CdO) form of Cd at three levels (0, 400 and 1000 mg kg(-1)), were applied at a fertilization level of 5000 kg ha(-1) in a laboratory microcosm study. The trial consisted of 60 microcosms (five replications per treatment), which were incubated in darkness at +20 degrees C and a constant relative air humidity …
Abundance and activity of nitrate reducers in an arable soil are more affected by temporal variation and soil depth than by elevated atmospheric [CO2]
2011
Elevated atmospheric carbon dioxide concentrations ([CO2]) might change the abundance and the function of soil microorganisms in the depth profile of agricultural soils by plant-mediated reactions. The seasonal pattern of abundance and activity of nitrate-reducing bacteria was studied in a Mini-FACE experiment planted with oilseed rape (Brassica napus). Three depths (0–10, 10–20 and 20–30 cm) were sampled. Analyses of the abundances of total (16S rRNA gene) and nitrate-reducing bacteria (narG, napA) revealed strong influences of sampling date and depth, but no [CO2] effects. Abundance and activity of nitrate reducers were higher in the top soil layer and decreased with depth but were not re…
Identification des espèces d'arbres à partir de données T-LiDAR Tree species identification using T-LiDAR data
2013
National audience; En raison de l'utilisation croissante des scanners LiDAR terrestre (T-LiDAR) dans le domaine forestier, le développement d'outils logiciels pour la mesure automatique d'attributs d'inventaire forestier est devenu un domaine de recherche important. De nombreux travaux portant sur la localisation des arbres dans un nuage de points, la mesure du diamètre à hauteur de poitrine (DHP) ou la mesure de la hauteur des arbres ont été décrits dans la littérature. Cependant, le problème de l'identification des espèces d'arbres à partir de données T-LiDAR a été peu abordé. La plupart des travaux utilisent des données LiDAR aéroportées et les espèces des arbres sont déterminées à l'éch…
Il sistema gerarchico d’analisi e le schede di caratterizzazione multidisciplinare e multiscala.
2014
La comprensione di strutture, processi e significati è alla base dello studio del paesaggio agrario. Alla base del metodo vi è l’analisi del paesaggio agrario tradizionale condotta integrando fra loro informazioni di carattere ecologico, ambientale, storico-culturale, economico nell’ottica di un approccio interdisciplinare, il solo in grado di riprodurne la natura sistemica e le dinamiche di interazione fra fattori naturali e antropici alla base della sua costruzione. Su questi presupposti si articola la descrizione multi- settoriale delle aree territoriali prescelte come aree modello: l’individuazione delle forme fisiche, della rete idrografica, dell’assetto agro-forestale, delle vicende s…
Labile carbon addition affects soil organisms and N availability but not cellulose decomposition in clear-cut Norway spruce forests
2014
We assessed the effects of sucrose addition on the biological and chemical properties of organic soil in clear-cut Norway spruce forests managed with or without wood-ash fertilization and mechanical site preparation. Sucrose addition increased the abundances of enchytraeids and tardigrades and soil moisture percentage in the clear-cut areas. Sucrose also increased nematode abundance in the non-fertilized plots. Sucrose reduced the pool of waterextractable NH4-N in the soil in the first year, but increased it in the second year. Sucrose addition did not affect the decomposition rate of cellulose strips. The biomass of ground vegetation was not affected by sucrose. Carbohydrate addition seems…
La Betulla dell’Etna: uno studio multidisciplinare sui fattori di deperimento della specie
2018
La betulla dell’Etna (Betula aetnensis Rafin), è una delle specie arboree che durante le ultime glaciazioni si è spinta verso sud e dove oggi costituisce popolazioni pressoché relitte localizzate esclusivamente in Sicilia sulla sommità dell’Etna. I betulleti sono presenti sui versanti orientali ed occidentali dell’Etna, ad un’altitudine compresa tra 1.400 e 2.000 m s.l.m. Si tratta di popolamenti pionieri che colonizzano substrati vulcanici inalterati e/o poco evoluti dove costituiscono a volte dei piccoli boschi puri o misti a pino laricio. Questi boschi in passato erano sottoposti a ceduazioni, che dal 1987 non sono state più eseguite a seguito della istituzione del Parco Regionale dell’E…
Anthropogenic Influences in Land Use/Land Cover Changes in Mediterranean Forest Landscapes in Sicily
2016
This paper analyzes and quantifies the land use/land cover changes of the main forest and semi-natural landscape types in Sicily between 1955 and 2012. We analyzed seven representative forest and shrubland landscapes in Sicily. These study areas were chosen for their importance in the Sicilian forest panorama. We carried out a diachronic survey on historical and current aerial photos; all the aerial images used to survey the land use/land cover changes were digitalized and georeferenced in the UTM WGS84 system. In order to classify land use, the Regional Forest Inventory 2010 legend was adopted for the more recent images, and the CORINE Land Cover III level used for the older, lower resolut…
Changes in Climate and Land Use Over the Amazon Region: Current and Future Variability and Trends
2018
This paper shows recent progress in our understanding of climate variability and trends in the Amazon region, and how these interact with land use change. The review includes an overview of up-to-date information on climate and hydrological variability, and on warming trends in Amazonia, which reached 0.6-0.7 °C over the last 40 years, with 2016 as the warmest year since at least 1950 (0.9 °C +0.3°C). We focus on local and remote drivers of climate variability and change. We review the impacts of these drivers on the length of dry season, the role of the forest in climate and carbon cycles, the resilience of the forest, the risk of fires and biomass burning, and the potential “die back” of …
Multiscale variation in drought controlled historical forest fire activity in the boreal forests of eastern Fennoscandia
2017
Forest fires are a key disturbance in boreal forests, and characteristics of fire regimes are among the most important factors explaining the variation in forest structure and species composition. The occurrence of fire is connected with climate, but earlier, mostly local-scale studies in the northern European boreal forests have provided little insight into fire-climate relationship before the modern fire suppression period. Here, we compiled annually resolved fire history, temperature, and precipitation reconstructions from eastern Fennoscandia from the mid-16th century to the end of the 19th century, a period of strong human influence on fires. We used synchrony of fires over the network…