Abstract
Among the largest disturbances affecting the health of spruce forests is the large-scale appearance of bark beetles. Knowledge on the spatial distribution of infected-spruce areas is vital for effective and sustainable forest management. Medium-spatial-resolution (20–30 m) satellite images are well-suited for spruce forest disturbance monitoring at a landscape and regional scale following bark beetle outbreaks. The aim of this study was to evaluate the health of a Norway spruce stand after a bark beetle outbreak based on Landsat 8 images and thematic and vector data, supplemented with selected climate variables. This research was conducted for a spruce stand in the Białowieża Forest District in 2013, 2015, 2017, and 2019. We hypothesised that the changes in spruce health would significantly influence the NDVI distributions during the studied years. Our research revealed that the weather conditions in the period of May–September were beneficial for beetle development and detrimental for the spruce stand, particularly in 2015, 2018, and 2019. SWIR-NIR-G and NDVI images showed a gradual deterioration in spruce health. The quantitative NDVI distributions varied; the minimum, mean, and median decreased; and the distribution shape of the index values changed over the studied years. An analysis of the spatial NDVI distributions revealed that the threshold NDVI value separating spruce stand areas in good and poor health was ca. 0.6. This study confirmed the applicability of NDVI for monitoring alterations in spruce stands, and indicated that spatial NDVI distributions can provide valuable support in forest monitoring at a landscape scale, since medium-resolution, ready-to-use NDVI images are easily available from the Landsat archives, facilitating the routine assessment of stand health.
Highlights
Forests cover about one third of the Earth’s land area and fulfil environmental, productive, and social functions [1,2]
We noted a decrease in the NIR accompanied by a considerable increase in the short-wave infrared (SWIR) equalling, or even exceeding, the values observed in the NIR (Figure 3)
A combination of Landsat 8 medium-resolution satellite imagery, thematic and vector data, supplemented by weather data proved to be an effective tool to objectively assess the current state of the studied spruce stand within the Białowieża Forest District under a bark-beetle infestation
Summary
Forests cover about one third of the Earth’s land area and fulfil environmental, productive, and social functions [1,2]. These roles are interdependent and related to each other in time and space. They are influenced by a variety of external factors. Among the largest disturbances affecting the health of forests in diverse geographical regions are natural hazards caused by the large-scale appearance of insects [3,4]. North America, considerable environmental and economic losses are caused by bark beetle (Ips typographus L.) infestations. Bark beetle is a permanent, integral element of the Norway spruce
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
