Assessing the accuracy for area-based tree species classification using Sentinel-1 C-band SAR data

Forest type (FTY) and tree species classification (SPP) over the Remn-ingstorp test site were performed using ground-based field observations and remote sensing data sources. The field inventory for the forest estate and for the surrounding natural reserve of Eahagen was carried out in 2016. The re-mote sensing data used were C-band Synthetic Aperture Radar (SAR) data from Sentinel-1. Dual polarization backscatter values were extracted for the period October 2017 - February 2019 and the area-based method was applied. The metrics obtained, i.e. monthly mean backscatter, were used to perform classification by machine learning models’ random forest (RF) and linear dis-criminant analysis (LDA). The models were evaluated with the leave-one-out cross-validation method and the classification outcomes were compared with reference values in terms of confusion matrixes. The best performing model was LDA with an overall accuracy of 88% for FTY and 61% for SPP, whereas RF achieved values of 84% for FTY and 56% for SPP. It was concluded that C-band SAR data can be used for FTY and SPP classification, but further investigation is needed to determine which factors affect the backscatter in order to obtain more accurate classifications

Assessing Forest Type and Tree Species Classification Using Sentinel-1 C-Band SAR Data in Southern Sweden

The multitemporal acquisition of images from the Sentinel-1 satellites allows continuous monitoring of a forest. This study focuses on the use of multitemporal C-band synthetic aperture radar (SAR) data to assess the results for forest type (FTY), between coniferous and deciduous forest, and tree species (SPP) classification. We also investigated the temporal stability through the use of backscatter from multiple seasons and years of acquisition. SAR acquisitions were pre-processed, histogram-matched, smoothed, and temperature-corrected. The normalized average backscatter was extracted for interpreted plots and used to train Random Forest models. The classification results were then validated with field plots. A principal component analysis was tested to reduce the dimensionality of the explanatory variables, which generally improved the results. Overall, the FTY classifications were promising, with higher accuracies (OA of 0.94 and K = 0.86) than the SPP classification (OA of 0.66 and K = 0.54). The use of merely winter images (OA = 0.89) reached, on average, results that were almost as good as those using of images from the entire year. The use of images from a single winter season reached a similar result (OA = 0.87). We conclude that multiple Sentinel-1 images acquired in winter conditions are feasible to classify forest types in a hemi-boreal Swedish forest

Logging Residue Assessment in Salvage Logging Areas: a Case Study in the North-Eastern Italian Alps

Salvage logging operations often occur after large disturbances and usually leave behind a substantial quantity of residues, which is fundamental for maintaining soil fertility and facilitating ecosystem dynamics. This study aims to estimate the amount of logging residues following salvage operations categorized by two wood harvesting systems: Cut-To-Length (CTL) and Full-Tree System (FT). Logging residues in the harvested areas were sampled using linear transects and the data collected were divided into classes based on diameter. The quantity of residues was estimated using the Brown method for Fine Wood Debris (FWD) and the Van Wagner method for Coarse Wood Debris (CWD). Furthermore, the carbon and nutrient content associated with logging residues were also determined, considering their interaction with the soil organic layer. Overall, a higher quantity of FWD was detected in the sites cleared with the FT system and a higher quantity of CWD in the sites logged with the CTL system. Differences could be observed for all three years and systems considered, but only the third year reported statistically significant results (p<0.01). The soil and residue chemical analysis for carbon and nutrient contents revealed a high amount of carbon stored in a potential layer of 10 cm of soil (up to 85 Mg·C·ha-1), while only up to 15 Mg·C·ha-1 for the woody material

Logging residues mass and volume from systematic literature review

Creation of a benchmark for logging residues after harvesting operations and forest management treatments. This dataset represents the most up-to-date collection of studies related to quantity and volume values of logging residue and shows how the relationship with working systems, treatments, and forest type is affecting these values. The dataset can be used to establish a line of comparison for further research and applications in the field of forest management giving insights on quantities that could be potentially present after harvesting operations

Effetti dei sistemi di utilizzazione e modalità di esbosco : studio preliminare sul rilascio di biomassa ed efficienza del cantiere forestale

Effetti dei sistemi di utilizzazione e modalit{\`{a}} di esbosco: studio preliminare sul rilascio di biomassa ed efficienza del cantiere forestale Alberto Cadei, Alberto Udali, Mihail Bacescu, Stefano Grigolato Nel contesto alpino, i sistemi di utilizzazione forestale si distinguono in processi di lavoro semimeccanizzati e completamente meccanizzati. In entrambi i casi, i sistemi di lavoro possono essere a pianta intera e legno corto. A seguito della tempesta Vaia, per garantire il recupero di ingenti volumi di legname danneggiato in superfici anche estese, si {\`{e}} fatto ampio ricorso a sistemi di utilizzazione completamente meccanizzati o sistemi semi-meccanizzati con l'impiego di macchine e attrezzature avanzate. I principali sistemi di utilizzazione impiegati sono stati quello del sistema con esbosco a legno corto completamente meccanizzato con l'impiego di harvester e forwarder e quello con esbosco con albero intero o parzialmente intero con gru cavo e l'allestimento del legname a bordo strada tramite processore. Questi due sistemi, dunque, possono avere un diverso effetto sulla quantit{\`{a}} di biomassa rilasciata in bosco a seguito dell'abbatimento, sramatura, allestimento ed esbosco: nel caso di harvester e forwarder, l'intera biomassa, che comprende ramaglie e parte del cimale, {\`{e}} rilasciata in bosco, mentre nel caso dell'utilizzo di gru a cavo, ramaglia e cimali vengono accumulati a bordo strada all'imposto in cui avviene l'allestimento del legname. Inoltre, l'attuale contesto operativo nelle Alpi orientali ha evidenziato il vantaggio, in termini di sicurezza per gli operatori, nell'impiego di sistemi di utilizzazione a completa meccanizzazione e l'impiego di macchine e attrezzature avanzante anche nel sistema di lavoro a pianta intera. Per meglio comprendere l'effetto della meccanizzazione in questi contesti, occorre per{\`{o}} anche valutare l'efficienza economica ed ecologica dei diversi sistemi di utilizzazione considerati, sia in termini di produttivit{\`{a}} che in termini di consumi di carburante per unit{\`{a}} di legname lavorato In questo contesto, il presente lavoro si pone due obbiettivi: a) valutare se l'adozione di un sistema di lavoro (pianta intera e legno corto) influenza in modo significativo i quantitativi di biomassa forestale presenti in bosco; b) valutare l'efficienza economica ed ecologica dei diversi sistemi di utilizzazioni e di lavoro considerati. I due obbiettivi sono stati verificati analizzando tre tipologie di cantieri: sistema di utilizzazione completamente meccanizzato a legno corto (cantiere harvester - forwarder) , sistema di utilizzazione semi-meccanizzato a pianta intera (cantiere gru a cavo - processore) e cantiere tradizionale semi-meccanizzato di tipo terrestre a legno corto (allestimento in bosco ed esbosco con trattore e verricello). La quantificazione e valutazione della biomassa rilasciata in seguito all'utilizzazione {\`{e}} avvenuta tramite transetti di campionamento. L'analisi della produttivit{\`{a}} e dei consumi {\`{e}} avvenuta utilizzando i dati di dettaglio forniti dalle macchine utilizzate sia in termini di consumi che di produttivit{\`{a}} (cantiere harvester e forwarder), o tramite cubatura manuale del legame esboscato (cantiere gru a cavo e trattore e verricello)

Economic Impacts of Forest Storms\u2014Taking Stock of After-Vaia Situation of Local Roundwood Markets in Northeastern Italy

Large timber availability after storms can lead to a drop in timber prices that can impact local markets. The Vaia storm, which occurred in Northeastern Italy at the end of October 2018, felled large volumes of timber, spruce in particular. To estimate the loss in volume and value connected to Vaia, data of roundwood sales from four local markets (Province of Trento, Province of Bol-zano, Veneto Region and Friuli Venezia Giulia Region) were collected before and after Vaia, as well as reports on the status of salvage operations. The results confirm that Vaia had a strong impact on Northeastern Italy. A large area of the forest was hit and massive volumes of wood were affected. The analysis on prices showed a negative trend in the post Vaia period due to an increase in volume per sale, especially for stumpage sales. It also highlighted the difficulties of storing the salvaged wood and the consequent fast saturation of the market. Although it was not possible to assess long-term effects on the four local markets, the presence and use of local e-commerce platforms proved useful in making roundwood sales more organized and efficient

Digging up into windstorms aftermath: understanding the effect of harvesting systems on salvage logging wood residues spatial distribution

Extreme disturbance events, such as climate change-driven ones, have increased their frequency, upsetting the ordinary management of forests, and impacting large areas with severe damage. As a consequence, when productive forests are hit, salvage logging operations represent the common way to recover part of the economic loose. However, salvage logging can lead to negative impacts in terms of soil erosion as well in terms of variation of soil carbon stock and nutrients. Commonly, in the European Alps, salvage logging operations in largely damaged forest areas can be referred generally to as two harvesting systems: i) Cut-to-Length (CTL) and ii) Full-Tree (FT) extraction systems. The application of the two harvesting systems can have a different effect on the type and quantity of logging residues and deadwood left on the forest ground, which in the short-medium term it can be reflected in terms of quantity and distribution of organic carbon and nutrients in the soil. To evaluate and gather more detailed information on the effects of forest operations, a valuable option is to rely on the use of precision forestry approaches, such as the use of remote sensing (RS) and Artificial Intelligence applications, for example, machine learning (ML). In the realm of forest operations, ML techniques and algorithms are the most used and can be fed with data directly extracted from the machines operating live on sites, and also with data retrieved through RS. Drone-borne data, for example, is now becoming the most used for its large potential and applicability, providing both large coverage and a high level of detail oversampled areas. The aim of this study is thus comparing two salvage logging areas and find any difference in terms of logging residue type, quantity, and spatial distribution according to the used harvesting system. Drone flights over two logging areas in the northeastern Alps to retrieve logging residues data were performed in 2022, the sites were windthrown in 2018 and harvested in 2021. A random forest model was built using RGB bands derived from the drone images, textural variables, and information from the surface model to classify elements in a clear-felled site. After the classification and noise removing operations, residues mass per hectare and distribution were estimated. Preliminary results will show the strengths and weaknesses of the method adopted in assessing the type of residues and their spatial distribution. Moreover, this application will highlight the different impacts of the two systems adopted in salvage logging operations with respect to residue type and quantity left on site