General remote sensing approach to forestry data processing and Current directions of remote sensing for research and development of forestry support products
Remote Sensing (RS) Approach to Forestry Data Processing
Forests are a crucial resource for sustaining life on Earth. They act as carbon sinks and are one of the most effective ways to combat climate change. They also represent a significant source of renewable energy in the form of wood fuel—currently, as much as solar, hydroelectric, and wind energy combined. Forests cover approximately 30% of all land on Earth and are home to 80% of the planet's terrestrial species (50% of animals). Therefore, they are one of the most valuable public assets on the planet, requiring protection from numerous threats, primarily stemming from human activities: agriculture, forest fires, urbanization, unregulated logging, and more.
RS methods enable addressing the following tasks for forestry development:
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Detailed examination of suspicious forested areas identified during fieldwork for changes and distributions over large areas;
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Monitoring anomalies over time based on image archives, maps, diagrams, reports, etc.;
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Forest classification (deciphering species and natural growth conditions);
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Indexing of leaf cover and individual tree stems (point analysis);
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Recording and spreading of parasitic diseases, harmful substances, insects, etc.
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Modeling emergencies (fires, floods, deforestation).
Large-scale and medium-scale monitoring of the forest environment can be carried out cost-effectively using remote sensing and sensor analysis from aerial or ground-based platforms. High-quality sensors (higher resolution, spectral ranges) and data collection technologies are becoming increasingly accessible, both for new Earth observation satellites, ground observation towers, and aircraft (manned and unmanned). Both individually and in combination, these various observation methods can provide valuable data for resource management or actions in response to abnormal events.
Remote sensing is primarily based on platforms: satellites, aircraft, UAVs, and remote ground imaging devices.
Sensors operating in the optical, infrared, and radar spectrums of electromagnetic waves are commonly used in practice.
The primary processing of image data from these sensors is traditionally conducted in the visible, multispectral, hyperspectral, near-infrared, and radar bands. Less frequently, but more actively in the thermal infrared, and in the USA for building 3D models of forested areas and individual trees, LIDAR is ubiquitous.

Modern Trends in Remote Sensing (RS) for Forestry Research and Product Development
As a trend, RS in forestry is moving towards detailed analysis of forest areas on a global scale, across different continents, countries, and individual plots.
The synergistic use of high-resolution optical and radar satellite data identifies historical and current forest conditions, forest size, density, and changes over time. Historical trends in deforestation, degradation, and tree phenology are derived.
For the analysis of current forest cover, solutions based on satellites, drones, or small aircraft with higher-resolution data collection methods are actively employed. Machine learning methods (artificial intelligence - AI) can be used for identifying forest cover over large areas and determining tree species.
Developed methods have been applied for over 10 years in reforestation and forest restoration projects, as well as in sustainable forest management:
Baseline Assessment
• Analysis of historical forest inventory and its dynamics.
• Analysis of current forest inventory using AI.
• CO2 (carbon dioxide) accounting.
• Development of future scenarios for sustainable management.
• Verification of CO2 certificates.
• Long-term monitoring.
Deforestation and Forest Degradation
The GEO Innoteer approach to monitoring, based on synergistic use of high-resolution optical and radar data, identifies the current state of forests, forest size, density, and changes over time. Historical trends in deforestation and forest degradation can be compared with current and future activity data.
Wildfire Consequences
Forest fires annually affect millions of hectares of tropical forests, especially in Southeast Asia, Russia, and Brazil. Repeated fires cause a gradual degradation of tropical and coniferous forest ecosystems.
Remote sensing provides an assessment of the impact of fires on the forest ecosystem and biodiversity in spatial and temporal scales. Forest fires alter the composition of forest vegetation, suppressing some species and stimulating the growth of others. Often, forests become more susceptible to fires because subsequent fires burn with greater speed and intensity, resulting in higher tree mortality. Forest managers can use data on fire impact and frequency to prevent fires and improve firefighting and forest management adaptation.
Forest Species Composition
Different types of forests require different management and protection measures. Dominant tree species are often unknown variables when planning forest resource use or managing protected areas. Using multi-temporal satellite data, different tree species' phenology can be obtained. Combining this information with digital elevation models, digital surface models, and canopy structure parameters, various types of forests can be mapped with high spatial detail.
Assessment of Forest Biomass
Combined RS methods provide forest biomass estimation with up to 80-90% accuracy, allowing conclusions to be drawn about other aspects of forest composition, carbon, oxygen, and forest ecosystem survival as a whole.
In 2023-2025, the RS community in the field of forestry outlines research directions:
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Classification, detection, and segmentation of vegetation cover.
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Detection and monitoring of animal movements in the forest environment.
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Measurement of moisture, temperature, and vegetation cover biomass.
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Detection and segmentation of fire, smoke, and burnt areas during forest fires.
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UAVs in forest environment monitoring.
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Multi-spectral and hyperspectral image sensors and forest analysis methods.
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Geolocation and mapping of events and landmarks in forest areas.
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Data collection from cameras and onboard sensors of manned and unmanned aircraft, spacecraft.
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Publicly available datasets containing aerial photos/videos of the forest environment.
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Benchmarking of aerial photo/video analysis methods in forest conditions.
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3D reconstruction of the forest environment using aerial photography, video, LiDAR, and Radar.
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Real-time data analysis for early detection and prediction of forest fires.
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Integration of large-scale satellite data with high-latency and small-scale aerial data with low latency.
Primary Sources of Remote Sensing Data - Images of Forests from Satellite, Aviation, and UAV Sensors
Imaging from Optical and IR RS Spacecraft
The assessment of forest resources using remote sensing began in the first half of the 20th century with the creation of local forest maps based on aerial photography.
The greatest contribution to the study of global forestry has been made by Earth remote sensing satellites (ERS):
Since 1972, with the launch of the first satellite sensor for Earth resource monitoring (ERTS - LANDSAT, 16 channels), significant advances have been made in remote sensing technology, allowing the assessment of forest resources over much larger areas. Technical specifications: sensors in panchromatic (15-meter resolution) and multispectral (including near and far thermal IR, with resolutions of 30 and 60 meters, respectively). There are three levels of detail:
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Level one relates to information about the spatial extent of forest cover, which can be used to assess dynamics;
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Level two includes information about species within forest plots;
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Level three provides information on the biophysical properties of forests.
Evaluating such information about forests allows for comprehensive monitoring of forest resources. The combination of remote sensing technologies with analysis methods, along with advancements in ecosystem modeling, has played a critical role in mapping, monitoring, and managing forest resources. LANDSAT-8 and 9 (USA) are still considered the most accessible and preferred satellites for capturing and subsequently analyzing forest resources.

Fig. Subsets of Landsat 8 images in bands 6, 5, 4 (R, G, B) for location A, acquired on (a) June 6, (b) August 25, and (c) October 28; and subsets of forest cover maps generated with (d) RF, (e) SVM, and (f) DT classifiers.
SENTINEL-2A and 2B (European Union) satellites are equipped with an optical-electronic multispectral sensor for imaging with resolutions ranging from 10 to 60 meters in the visible, near-infrared (VNIR), and shortwave infrared (SWIR) spectra, including 13 spectral channels. For example, using multispectral imagery from these satellites, three classification methods (artificial neural network (ANN), support vector machine (SVM), and spectral angle mapper (SAM)) were researched and accepted for comprehensive mapping of secondary forest cover.

Fig. Comparison of Sentinel-2A spectral bands with Sentinel-2A RGB imagery of forest areas
Practically analogous to LANDSAT, in terms of characteristics, is the satellite ASTER (USA). Space images obtained by the ASTER equipment from the Terra satellite have 14 spectral bands: 3 in the visible and near-infrared, 6 in the mid-infrared, and 5 in the thermal infrared, with spatial resolutions of 15, 30, and 90 meters, respectively, and a frame size of 60x60 km. For example, Terra/ASTER data have a high potential for distinguishing peat bog forests in Canada based on vegetation class and forest cover density. Maps of forest cover density class and vegetation class were obtained for many forest areas. The accuracy of the results was calculated based on the Maximum Likelihood Classification (MLC) confusion matrix.

Fig. Color infrared composite image (channels 321) of ASTER images taken on April 28, 2007. The center of this subset is an area covered with forests and continuous forest areas.
More high-quality images in terms of resolution for forestry tasks, but with fewer channels in the multispectral range, can be obtained from the SPOT satellites (Azerbaijan/France). The spatial resolution is 1.75 - 6 meters. SPOT-6/7 images were used to create the largest global Urban Atlas database, including forestry, which is used to calculate multiscale forest morphological features using the Random Forest classifier.

Fig. Location of the training sample for simple random sampling and stratified random sampling on SPOT 6/7 false-color image composites in 2018-2019.
And finally, high and super high-resolution satellites (PLANET Lab and MAXAR).
PlanetScope is a constellation of nanosatellites. The uniqueness of the group is that in one day, the satellites capture more than 200 million square kilometers and cover almost the entire world with the most up-to-date images. The satellites have a spatial resolution of 3.7 meters in four spectral channels (RGB+NIR), with no panchromatic channel. Satellite imaging is continuous, allowing them to work completely autonomously: they do not need to be programmed for new imaging. Using PlanetScope, an open portal was created for forestry professionals to see which trees were recently removed due to bark beetle activity and which ones remained standing due to bark beetle invasion.

High-frequency high-resolution images provide continuous monitoring of forest management activities - from planning to logging and reporting.
WorldView-3 is the first commercial super high-resolution multispectral satellite with a large payload. With the WorldView-3 satellite, there is a 31 cm resolution in panchromatic mode, 1.24 m in multispectral mode, 3.7 m in shortwave infrared (SWIR) channels, and 30 m with the CAVIS equipment. Importantly, the satellite has an additional red band that is sensitive to vegetation. Identifying tree species is an important issue in forest management and monitoring. In recent years, the identification of tree species based on high-resolution spatial imagery at 0.3 m spatial resolution from WorldView-3 has been extensively studied. This is because some tree species have a very high market value for wood. In addition, tropical forests store a large carbon stock, contributing to a vast amount of aboveground and underground biomass. The most important bands in classification were the blue bands, followed by bands related to the red bands.

Evaluation of tree stocks from WorldView-3 images.
So far, among optical and multispectral range satellites, there is a unique hyperspectral satellite, Earth Observation EO-1, which has already ceased to exist in orbit but is actively used in the archive. The three main instruments on board EO-1 are ALI (analogous to LANDSAT), Hyperion, and Linear Etalon Imaging Spectrometer Array (LEISA) Atmospheric Corrector (LAC). Hyperion is a grating spectrometer with a 30-meter ground resolution, covering a 7.7 km strip. It captures in the spectral range of 400-2500 nm with a 10 nm interval for each of the 220 channels. LAC is a spectrometer that covers the spectral range from 900-1600 nm and was used for one year to monitor atmospheric water absorption lines for atmospheric correction in multispectral images. Hyperion hyperspectral images with Random Forest (RF), Support Vector Machine (SVM), and Multivariate Adaptive Regression Splines (MARS) classifiers were obtained for various forest cover groups, namely broadleaf and coniferous forests. Statistical data obtained from the classification confusion matrix were widely used to assess the accuracy of thematic maps obtained.

Image obtained from Hyperion (left) in false colors (R: band 29, G: band 14, B: band 7; Hyperion subset (center) covering the study area; (right) SVM-classified image covering an enlarged part of the scene using orthophotos.