Large-scale two-phase estimation of wood production by poplar plantations exploiting Sentinel-2 data as auxiliary information
Agnese Marcelli,
Walter Mattioli,
Nicola Puletti,
Francesco Chianucci,
Damiano Gianelle,
Mirko Grotti,
Gherardo Chirici,
Giovanni D' Amico,
Saverio Francini,
Davide Travaglini,
Lorenzo Fattorini,
Piermaria Corona
Affiliations
Agnese Marcelli
University of Tuscia, Department for Innovation in Biological, Agro-food and Forest systems, Viterbo, Italy; Fondazione Edmund Mach, Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, San Michele all’Adige, Italy
Walter Mattioli
University of Tuscia, Department for Innovation in Biological, Agro-food and Forest systems, Viterbo, Italy; CREA, Research Centre for Forestry and Wood, Arezzo, Italy
Nicola Puletti
CREA, Research Centre for Forestry and Wood, Arezzo, Italy
Francesco Chianucci
CREA, Research Centre for Forestry and Wood, Arezzo, Italy
Damiano Gianelle
Fondazione Edmund Mach, Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, San Michele all’Adige, Italy
Mirko Grotti
CREA, Research Centre for Forestry and Wood, Arezzo, Italy; University of Roma La Sapienza, Department of Architecture and Design, Rome, Italy
Gherardo Chirici
University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy
Giovanni D' Amico
University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy
Saverio Francini
University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy; University of Molise, Department of Agricultural, Environmental and Food Sciences, Campobasso, Italy
Davide Travaglini
University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy
Lorenzo Fattorini
University of Siena, Department of Economics and Statistics, Siena, Italy
Piermaria Corona
CREA, Research Centre for Forestry and Wood, Arezzo, Italy
Growing demand for wood products, combined with efforts to conserve natural forests, have supported a steady increase in the global extent of planted forests. Here, a two-phase sampling strategy for large-scale assessment of the total area and the total wood volume of fast-growing forest tree crops within agricultural land is presented. The first phase is performed using tessellation stratified sampling on high-resolution remotely sensed imagery and is sufficient for estimating the total area of plantations by means of a Monte Carlo integration estimator. The second phase is performed using stratified sampling of the plantations selected in the first phase and is aimed at estimating total wood volume by means of an approximation of the first-phase Horvitz-Thompson estimator. Vegetation indices from Sentinel-2 are exploited as freely available auxiliary information in a linear regression estimator to improve the design-based precision of the estimator based on the sole sample data. Estimators of the totals and of the design-based variances of total estimators are presented. A simulation study is developed in order to check the design-based performance of the two alternative estimators under several artificial distributions supposed for poplar plantations (random, clustered, spatially trended). An application in Northern Italy is also reported. The regression estimator turns out to be invariably better than that based on the sole sample information. Possible integrations of the proposed sampling scheme with conventional national forest inventories adopting tessellation stratified sampling in the first phase are discussed.
