Search results for "Canopy"

Differences of raw cork quality in productive cork oak woods in Sicily in relation to stand density

2010

Differences of raw cork quality, in terms of thickness and porosity, were observed in productive cork oak (Quercus suber L.) stands in the Nebrodi and Iblei mountains of Sicily in relation to stand density. Five study areas were chosen across a range of different stand density satisfying specific sampling requirements among two managed cork oak stands. Analysis of variance using Fisher-Snedecor's F test (p<0,05) were used to identify statistically significant differences of cork quality and sylvicultural, dendrometric and cork stripping parameters between study areas within each stand and also between stands. Relationships between cork quality and sylvicultural and dendrometric parameters w…

Soil and organic carbon redistribution in a recently burned Mediterranean hillslope affected by water erosion processes

2022

Forest fires cause many changes in the physical, chemical and biological soil properties such as aggregation and soil organic carbon contents (SOC) as well as on soil hydrology and erosion processes. Most studies on post-fire soil erosion in Mediterranean environments have been plot-based and research at hillslope or broader scale is scarce. Understanding SOC nature, distribution and modifications, as produced by forest fires and erosion, has become crucial to model and define the role of soil erosion as source or sink of C, and to sustainably manage ecosystem services related to the soil resource. This research provides data about the loss and redistribution of soil and SOC in a Mediterran…

Evaluation of different mechanical fruit harvesting systems and oil quality in very large size olive trees

2014

In 2006 and 2009, trials were carried out in the Apulia region in Southern Italy to evalu-ate the possibility of mechanizing olive harvesting in groves of old and very large trees. The trees belonged to the cultivars ‘Cellina di Nardò’ and ‘Ogliarola Salentina’. They were 60-100 years old and 7-9 m tall with a canopy volume of 140-360 m3. In the first half of November 2006, with a mechanical beater mounted on a tractor plus hand-held pneumatic combs, the harvesting yield was close to 90% of the total olives present in the canopy, and the harvesting working productivity was around 60 kg of harvested olives h-1 worker-1. With a self-propelled shaker attached to the main branches the harvestin…

Lifestyle dependent occurrence of airborne fungi

2018

Abstract. Fungi play important roles in the environment, agriculture, and human health. Most fungal species spread by wind-driven dispersal of spores, determining their occurrence and distribution in different environments. The dynamics of airborne fungi and their dependence on lifestyle and environmental conditions, however, are not well characterized. Here, we categorize the fungi detected in coarse and fine aerosol samples from continental boundary layer air using a lifestyle classification scheme that differentiates whether the fungi are (A) primarily associated to herbaceous or woody plants and (B), whether they are saprophytic, plant pathogenic, or surface inhabitants. Herbaceous fung…

Conversion of nadir, narrowband reflectance in red and near-infrared channels to hemispherical surface albedo

1997

Abstract Measured nadir-viewed narrow-band reflectanees in red and near infrared channels simulating AVHRR Channels 1 and 2 are compared with measured integrated solar spectrum hemispherical albedos. Reflectanees and albedos were measured from an aircraft over four widely different vegetation surfaces in southeastern Tasmania (Australia). A linear function is used to simultaneously correct for narrow band to broad band conversion errors and to convert nadir viewed reflectances to hemispherical albedos. While the application of the conversion equation presented is limited to the vegetation types of the study, the equation is independent of vegetation type. Results indicate that the reflectan…

Corrigendum to ‘Pathway using WUDAPT's Digital Synthetic City tool towards generating urban canopy parameters for multi-scale urban atmospheric model…

2019

Atmospheric dry deposition processes of particles on urban and suburban surfaces: Modelling and validation works

2019

Abstract Dry deposition process is one of the important pathways for the removal of particles from atmosphere. It is the result of a combination of different environmental and physical factors as atmospheric conditions, particle properties, characteristics of the canopy. For this latter factor, urban canopy represents unevenly combinations of different types of surface elements that increases the complexity of deposition process phenomena. Therefore, particle dry deposition on urban surfaces is not easy to configure and, although empirical or semi-empirical models in literature have been developed to address this aspect, there is not standardized and commonly accepted criteria, especially f…

Morphology and yield response to weed pressure by corn hybrids differing in canopy architecture

2001

Abstract Recently, corn ( Zea mays L.) hybrids accumulating more leaf area above the ear, maturing earlier, yielding better in narrower row spacings and tolerating higher population densities than conventional hybrids have been developed. However, no research has been conducted to assess their ability to compete with weeds. The objective of this study was to quantify morphological and grain yield responses of hybrids with differing canopy architectures to the presence and absence of weeds. Field experiments were conducted in 1996, 1997, and 1998 at Ste. Anne de Bellevue, Quebec and in 1996 at Ottawa, Ontario. Three hybrids, leafy reduced-stature (LRS), late maturing big leaf (LMBL), and con…

Upscaling leaf gas exchange measurements to the whole grapevine canopy: An update

2009

This review first revisits current knowledge about single-leaf function, viz. photosynthesis, chiefly in relation to environmental factors, that underscores the importance of multiple summer stresses. Emphasis is placed on the response different genotypes show under light and heat stress with or without soil-water shortage. Secondly, it tackles the thorny issue of extrapolating single-leaf readings to the whole-canopy level, with special reference to both methodological and physiological implications. Whole-canopy gas-exchange systems deliver and emphasise the usefulness of such an approach in achieving key research goals. One case in point is quantifying the amount and dynamics of canopy g…

Characterization of the surface emissivity and temperature at heterogeneous sites for different zenith viewing angles using remote sensing

2020

Para estimar con precisión la temperatura de la superficie terrestre (TST) es necesario conocer con exactitud la emisividad de dicha superficie. Sobre zonas vegetadas, la estimación de la emisividad es más compleja debido a las reflexiones múltiples de la radiación (emitida y reflejada) entre los distintos elementos que forman la vegetación (suelo y elementos de la planta). En la literatura pueden encontrarse diversos métodos que modelan la emisividad de la vegetación. En este trabajo, se ha profundizado en el análisis y evaluación de los modelos de transferencia radiativa (MTR) para la obtención de la emisividad direccional de la vegetación. Los modelos utilizados para este estudio han sid…