Large-scale monitoring of coppice forest clearcuts by multitemporal very high resolution satellite imagery. A case study from central Italy

Abstract

Reliable assessment of forest resource stock, productivity and harvesting is a commonly agreed objective of environmental monitoring programs. Distinctively, the assessment of wood harvesting has become even more relevant to evaluate the sustainability of forest management and to quantify forest carbon budget. This paper presents the development and testing of procedures for assessing forest harvesting in coppice forests by very high resolution (VHR) satellite imagery. The study area is located in central Italy over approximately 34,000 km 2 . A set of SPOT5 HRG multispectral images was acquired for the study years (2002)(2003)(2004)(2005)(2006)(2007). Official administrative statistics of coppice clearcuts were also acquired. More than 9500 clearcuts were mapped and dated by on-screen interpretation of the SPOT5 images. In a subset of the study area various methods for semi-automatic clearcut mapping were tested by pixel-and object-oriented approaches. The following results are presented: (i) clearcut map developed by visual interpretation of the SPOT5 images resulted in high thematic (overall accuracy of 0.99) and geometric (root mean square error of clearcut boundary delineation of 5.3 m) reliability; (ii) object-oriented approach achieved significantly better accuracy than pixel-based methods for semi-automatic classification of the coppice clearcuts; (iii) comparison between mapped clearcut area and official forest harvesting statistics proved a significant underestimation by the latter (65% of the total mapped clearcut area). A sample-based procedure exploiting VHR satellite imagery is finally proposed to correct the official statistics of coppice clearcuts.

The Greenhouse Gas Balance of Italy

“…The results from Chirici et al (2011) confirmed a 35 % underestimation of official wood harvesting statistics from coppice forests in Italy originally hypothesized by Cutolo (2000) and Corona et al (2004). Multitemporal high resolution remotely sensed images can be operatively used with a probabilistic sampling procedure to obtain a more reliable data on annual wood harvesting extents.…”

“…The results recently published in Chirici et al (2011) are here synthesized. The integrated use of remote sensing technologies should be considered.…”

“…Chirici et al (2011) compared the visual on-screen photo-interpretation of infrared false color composite SPOT5 HRG images with semi-automatic classification systems based on both pixel-based and object-based approaches. Chirici et al (2011) compared the visual on-screen photo-interpretation of infrared false color composite SPOT5 HRG images with semi-automatic classification systems based on both pixel-based and object-based approaches.…”

Use of geographically weighted regression to enhance the spatial features of forest attribute maps

“…1,2 Conventionally, statistical assessments of forest attributes are obtained through inventories based on ground sampling, which are expensive and time consuming to perform. [6][7][8] In regard to optical images, several studies have been conducted on the integration of ground and satellite data to map these forest attributes over both Europe [9][10][11] and North America. 5 Satellite remote sensing techniques are a valuable alternative source of information about forest attributes at various spatial and temporal scales.…”

Province-scale comparison between harvest wood products reported by ISTAT and forested areas reported by INFC

“…L'applicazione di questo nuovo approccio non può naturalmente prescindere da una accurata quantifi cazione delle utilizzazioni forestali realizzate a livel lo nazionale. Tale aspetto tuttavia, almeno per l'Ita lia, risulta tuttora problematico (Corona et al 2007, Pettenella & Ciccarese 2009, Chirici et al 2011, stan te la scarsa attendibilità dei dati riportati dalle stati stiche ufficiali pubblicate principalmente a cura del l'Istituto Nazionale di Statistica (ISTAT 2005).…”