Precision Forestry : A Revolution through Remote Sensing Technology
Introduction
Precision forestry is a method in which the characteristics of forests, treatments, biodiversity preservation, and recreational opportunities can be accurately determined, at the forest stand, plot, or individual tree level. Precision forestry requires a plethora of information and data which needs to be accurate, spatially detailed, up to date, and must characterize the composition, structure and productivity of a forest. The world today needs the application of the ideas of precision forestry concepts in order to achieve the forest management goals, improving the decision making process and providing several economic and ecological benefits. Out of all best known modern technologies, remote sensing technologies has become the mainstay of precision forestry transformation process because it is seen that high-resolution satellite imagery has proven extremely useful for repetitive timeline-based data collection of all forest management components with its synoptic view and fast processing of large quantities of data. High spatial resolution (30 cm or less) imagery can provide every fine details of a forest which can be mapped and analyzed for different subject of research. It provides highly repeatable measurements, actions and processes to initiate, cultivate, and harvest trees, as well as to protect enhance riparian zone, wildlife habitat, and other environmental resources. It provides valuable information and linkages among resource managers, the environmental community, manufactures and public policy makers.
What is Precision Forestry?
Precision Forestry is the use of tools and technology to collect data to make decisions for site-specific management. It aims to improve wood quality, protect the environment, reduce waste, and increase profits.
It can be used in all phases of forestry, such as planning, site operations, monitoring, processing, and marketing.
Precision forestry takes advantage of the understanding of ecological processes in forests, which has been undergoing in the past. Instead of following a single plan for the entire area, accurate data and advanced analytics can optimize and fine-tune management decisions to suit site conditions, such as soil type and fertility, slope, etc. This can ensure the following:
- Site specific species selection and planting to improve survival of seedlings.
- Site-specific fertilization treatments based on granular assessment of soil nutrients deficiencies.
- Regular monitoring of the health of trees.
- Automation of site operations, from nurseries to wood logistics.
- Digital forest inventory and tracking of wood during transport.
- Combination of spatial data on tree growth, yield, and environmental conditions to create growth and yield models for future management.
Who Can Use Precision Forestry?
Precision management is important for both economic and ecological reasons.
Public and private organizations involved in natural forest conservations are interested in this new forestry method for –
- Carbon sequestration,
- Carbon accounting,
- Watershed development,
- Soil conservation,
- Forest preservation, and
- Biodiversity conservation.
The wide range of end users may be comprised of:
- Public supervisory or regulatory authorities (supervision of agricultural, construction and production activities in forests, wild and protected forests);
- Forest service (violations of the existing land allocation regulations for commercial or sanitary logging, updating forestry maps);
- Police, special forces and patrol services (detection of illegal logging areas and fight against poachers);
- Environmental service (monitoring of forest restoration activities);
- TV and radio companies and other mass media (propaganda against poachers and measures against illegal logging);
- People living near forests (obtaining objective and reliable information regarding the pace and extent of deforestation and forest degradation).
How Satellite Remote Sensing is helping in Precision Forestry?
Satellite remote sensing data provides a unique way for mapping forest attributes on spatially extensive areas, from regional to global scale. For this reason, satellite products have long been widely used for many forestry application including forest inventory, biodiversity assessment and monitoring, global change, as well as to support decision-making sustainable forest management
Remote sensing through high-resolution satellite imagery relies on spectral images to give large-scale information on forest composition, forest health, land cover change, land use analysis, drought conditions, fire and flood risks, logging activity etc… Let’s discuss 5 main applications of remote sensing satellite data applications employed in Precision Forestry.
- Land Cover/ Land Use Change Detection
Forests are dynamic ecosystems, subject to both natural and anthropogenic agents of change. Wildfire, harvesting and other human activities alter the tree-covered area present in forests. So identifying both the changes that occurred in the past and the alteration taking place in the present is very important as a part of precision forestry. Using time series of high-resolution satellite imagery, weekly, monthly or annual land cover maps can be generated that will indicate the past disturbance history (such as wildfire and harvesting) and the ongoing dynamics due to both natural and manmade causes.
A Land Cover analysis based on classified WorldView 2 Imagery
Forest degradation detection based on historical and recent satellite imagery classification.
- Determination of Areas with Plant Stress
The natural conditions in which plants and trees grow are neither uniform nor controlled. Many changes or fluctuations, even if they are temporary, can have a negative impact on and stress plants. Stress can have serious repercussions on various phases of a plant’s growth and, ultimately, crop productivity. The factors which can lead to stress can be one of two types: abiotic or biotic.
Abiotic stress factors stem from the environment in which the plant or tree grows and include light, temperature, moisture, nutrients, and soil conditions. Whereas biotic stress factors arise from the other living organisms such as pathogens and herbivores, with whom the plants coexist and interact with.
High-resolution satellite imagery can be used to generate various vegetation index models to determine such plant stress at an early stage and become an integral part of precision forestry by providing a monitoring and decision support system for remedial measures and actions.
- Tree detection for automated forest inventories
Forest inventories provide support to the management and conservation activities in rural or urban forests or even in tree plantation. It is very important, especially during the initial years after the plantation is done. Accurate information about the mortality and growth dynamics of the plantation can help in improved decision making related to replanting, soil improvement, and early thinning activities.
Remote sensing with high spatial resolution is a cost-effective and reliable way to obtain information about trees. The tree crown is the basis of the data required for the inventory, for it allows determining not only its size but also its position, crown closure, and, in some cases, the species. It also allows the derivation of parameters such as the density of the population, the health condition of the trees, the volume, the biomass, and the carbon sequestration rates. This information is crucial to a series of applications such as counting and monitoring trees in orchards or under power lines to prevent damage and accidents.
Using high-Resolution satellite imagery detailed digital elevation model of the plantation area can be created, which can help in differentiating the trees crown from the background terrain. Using different image segmentation algorithms and other advanced image processing and analysis techniques, individual trees can be isolated and their position and size can be determined. Further it can be imported to any GIS software for all kind of forest statistics analysis.
Tree Counting using High-Resolution Satellite Imagery
- Monitoring Logging Impact and Detect Illegal Logging
The main cause of deforestation is logging activities and regular monitoring of deforestation is currently an urgent task for many countries. The availability of relevant and reliable information ensures effective monitoring of compliance with the legislative acts providing protection and sustainable use of forests, wildlife and the existing forest regulations.
Modern Earth remote sensing satellites have been widely utilized to solve a range of environmental monitoring and emergency control tasks. It allows managers of any level to receive the most timely and reliable information about the state of forests and related economic activities in any of the most remote and inaccessible areas, which is unattainable with ground surveys.
High-resolution satellite imagery can be used to classify land cover pattern of the area of interest and different vegetation indices maps such as NDVI, EVI, ARVI, SAVI, etc… can be created to detect significant canopy gaps caused due to deforestation by logging activities. Change detection analysis can be done on a weekly or monthly basis at any scale to identify remotely forest cover changes due to the illegal logging activities taking place in deep dense forest areas, which otherwise is difficult to access physically.
Satellite composite image shows areas of temporal change, such as seasonal agriculture or logging, display as various shades of blue, depending on the degree of change that occurs. Stable, forested areas show as shades of green.
- Real-time Detection of Forest Fires
Satellite remote sensing offers a useful tool for forest fire detection, monitoring, management and damage assessment. During a fire event, active fires can be detected by detecting the heat, light and smoke plumes emitted from the fires. Hot spots detected in low-resolution satellite imagery provide information on the general locations, spatial distributions and temporal evolution of fires.
High-resolution imagery can be used to zoom in onto the hot spot areas to accurately locate the individual fires and to determine the types of land cover affected by fires. Burn scar maps at various scales can be produced from satellite imagery. The burn scar maps, together with land cover and vegetation maps (also derivable from satellite imagery), are useful in ascertaining the types of land affected by fires during a fire event for effective firefighting and fire management, and for damage assessment.
High-resolution satellite imagery detecting forest fire. The red outlines indicate the hotspot.
Conclusion
Managing forests in an increasingly environmental- and profit- concerned market have become a complex challenge for forest planning. Precision forestry could generate future forestry operations at a macro and micro level in a more economically and ecologically sustainable way to satisfy public and environmental demands. Modern remote sensing technologies can contribute to higher precision in forest management and decision making process. It holds great potential to develop automated monitoring and management applications and thus reduce labor requirements. Its importance relies on usage of high-resolution satellite imageries and improved algorithms and models, to automate maximum processes related to monitoring and management of forest resources such as LULC analysis, illegal logging activities detection, estimating plant stress, maintaining updated forest inventories and real-time detection of forest fires. Thus remote sensing technologies have ushered in a revolutionary change to the forestry industry.