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Pubblicazioni Scientifiche
Filtri di ricerca 2 risultati
Pubblicazioni per anno
Estimating canopy and stand structure in hybrid poplar plantations from multispectral UAV imagery
Romano
,
Elio
,
Brambilla
,
Massimo
,
Chianucci
,
Francesco
,
Tattoni
,
Clara
,
Puletti
,
Nicola
,
Chirici
,
Gherardo
,
Travaglini
,
Davide
,
Giannetti
,
Francesca
canopy photography
canopy structure
poplar plantation
texture metrics
digital camera
gclm metrics
unmanned aerial vehicle
Mostra abstract
Accurate estimates of canopy structure like canopy cover (CC), Leaf Area Index (LAI), crown volume (Vcr), as well as tree and stand structure like stem volume (V_st) and basal area (G), are considered essential measures to manage poplar plantations effectively as they are correlated with the growth rate and the detection of possible stress. This research exploits the possibility of developing a precision forestry application using an unmanned aerial vehicle (UAV), terrestrial digital camera and traditional field measurements to monitor poplar plantation variables. We set up the procedure using explanatory variables from the Grey Level Co-occurrence Matrix textural metrics (Entropy, Variance, Dissimilarity and Contrast) calculated based on UAV multispectral imagery. Our results show that the GCLM texture derived by multispectral ortomosaic provides adequate explanatory variables to predict poplar plantation characteristics related to plants' canopy and stand structure. The evaluation of the models targeting the different poplar plantation variables (i.e. Vcr, G_ha, Vst_ha, CC and LAI) with the four GLCM explanatory variables (i.e. Entropy, Variance, Dissimilarity and Contrast) consistently higher or equal resulted to R<sup>2</sup> ≥0.86. © 2024, Editura Silvica. All rights reserved.
Influence of image pixel resolution on canopy cover estimation in poplar plantations from field, aerial and satellite optical imagery
Chianucci
,
Francesco
,
Puletti
,
Nicola
,
Grotti
,
Mirko
,
Bisaglia
,
Carlo
,
Giannetti
,
Francesca
,
Romano
,
Elio
,
Brambilla
,
Massimo
,
Mattioli
,
Walter
,
Cabassi
,
Giovanni
,
Bajocco
,
Sofia
,
Li
,
Linyuan
,
Chirici
,
Gherardo
,
Corona
,
P.
,
Tattoni
,
Clara
Mostra abstract
Accurate estimates of canopy cover (CC) are central for a wide range of forestry studies. As direct measurements are impractical, indirect optical methods have often been used to estimate CC from the complement of gap fraction measurements obtained with restricted-view sensors. In this short note we evaluated the influence of the image pixel resolution (ground sampling distance; GSD) on CC estimation in poplar plantations obtained from field (cover photography; GSD < 1 cm), unmanned aerial (UAV; GSD <10 cm) and satellite (Sentinel-2; GSD = 10 m) imagery. The trial was conducted in poplar tree plantations in Northern Italy, with varying age and canopy cover. Results indicated that the coarser resolution available from satellite data is suitable to obtain estimates of canopy cover, as compared with field measurements obtained from cover photography; therefore, S2 is recommended for larger scale monitoring and routine assessment of canopy cover in poplar plantations. The higher resolution of UAV compared with Sentinel-2 allows finer assessment of canopy structure, which could also be used for calibrating metrics obtained from coarser-scale remote sensing products, avoiding the need of ground measurements. © 2021 Centro di Ricerca per la Selvicoltura, Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria. All rights reserved.