Abstract
ABSTRACT This study evaluated the suitability of different airborne laser scanning (ALS) datasets for the prediction of forest canopy fuel parameters in managed boreal forests in Finland. The ALS data alternatives were leaf-off and leaf-on unispectral and leaf-on multispectral data, alone and combined with aerial images. Canopy fuel weight, canopy base height, biomass of living and dead trees, and height and biomass of the understory tree layer were predicted using regression analysis. The considered categorical forest parameters were dominant tree species, site fertility and vertical forest structure layers. The canopy fuel weight was modeled based on crown biomass with an RMSE% value of 20–30%. The canopy base heights were predicted separately for pine and spruce stands with satisfactory results the RMSE% values being 9–10% and 15–17%, respectively. Following the initial classification of the existence of an understory layer (with kappa-values of 0.47–0.53), the prediction of understory height performed well (RMSE% 20–25%) but the understory biomass was predicted with larger RMSE% values (about 60–70%). Site fertility was classified with kappa-values of 0.5–0.6. The most accurate results were obtained using multispectral ALS data, although the differences between the datasets were minor.
Highlights
Forest fires are one of the greatest natural hazards faced by boreal forests
The predictor variables in the Linear discriminant analysis (LDA) and linear regression (LR) models are shown in Tables 4 and 5, respectively
The role of airborne laser scanning (ALS) intensity features was emphasized in the classifications and they were selected by the heuristic feature selection in each case (Table 4)
Summary
Forest fires are one of the greatest natural hazards faced by boreal forests. fire is a natural phenomenon and is an important factor in maintain ing biodiversity and in natural regeneration (Esseen et al, 1997; Koutsias & Karteris, 2003). In Nordic countries, such as Finland, approximately 1000 forest fires occur, on average, each year (Lehtonen et al, 2016). The area burnt in Finland is relatively small because of active fire suppression, and the heterogeneity of forested areas with numerous lakes and swamps, and a dense forest road network, which create natural obstacles to fire spread (Lehtonen et al, 2014). In August 2014, a large forest fire of approximately 150,000 hectares occurred and rapidly spread in Västmanland, Sweden (Bohlin et al, 2017). During a hot dry period in the summer of 2018, several substantial forest fires occurred in Sweden and in Finland, providing further evidence of the increasing susceptibility of managed boreal for ests to fire. The risk of forest fires is expected to increase in Finland and elsewhere in the boreal zone under a warming climate, due to increased frequency of drought periods (Lehtonen et al, 2014, 2016; Ruosteenoja et al, 2018)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
