Forest monitoring is the recurrent measurement of forest parameters to identify changes over time. There is currently a rising demand for monitoring, as well as growing capacities for it. The research explores whether the location of these studies is in the countries where monitoring is most needed. Three characteristics, biophysical conditions, anthropogenic influences, and forest monitoring capacities were used to identify the need for tropical forest monitoring advances.
This provided an understanding as to where research should be targeted in the future. The findings revealed that research appears to be concentrated in countries with strong forest monitoring capabilities that face challenges due to biophysical and anthropogenic influences (e.g., logistically difficult ground sampling and rapid pace of forest change, respectively). Consequently, future research could be targeted in countries with lower capacities and higher needs, in order to improve forest monitoring and conservation.
Forests, which cover about 30% of the Earth’s surface, are among the most diverse ecological environments on the planet. Tropical forests encompass almost half of these areas and are located between the latitudes 23.5◦ North and South of the equator. They play a crucial part in the regulation of the climate by storing and absorbing carbon. In addition, they support the maintenance of water cycles, protect soils, reduce erosion, and provide economic and social benefits. Particularly in tropical regions, anthropogenic disturbances have led to land use and land cover changes and related loss of forest area and resources. This unsustainable use of natural resources has resulted in a reduction in ecological services provided by forests.
Worldwide, deforestation and degradation are arguably the greatest threats to tropical forests, with conversion for agriculture being the most common driver. Deforestation, additionally, causes degradation and biodiversity loss, loss of biomass, GHG emissions, and reduction in mitigation potential (which leads to higher costs for decreasing emissions). Prevention of deforestation and forest degradation, and sustainable forest management which aims to protect forest biomass and related carbon stocks is particularly relevant for climate change, and for the security and continuity of other forest functions.
Forest monitoring is the consistent and frequent measurement of forest parameters, which can be physical, biological, or chemical, and can be used to set standards for detecting changes over time. Monitoring is especially important in tropical forests which are disappearing at an alarming pace. REDD+, or “reducing emissions from deforestation and forest degradation in developing countries, and the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks in developing countries” is an initiative set up to conserve forests in developing (often tropical) countries. In order to track progress, monitoring, reporting, and verification systems are required as part of REDD+ initiatives, of which forest monitoring is a key element. To obtain the best results, monitoring must be carried out using reliable methodologies over a long period of time. The regularity of monitoring, as well as the time it is in operation, increases its value, by allowing the planning of actions based on monitoring results. A complete monitoring approach incorporates high-resolution remotely sensed data with observations and ground measurements, offering a good foundation for evaluating forest dynamics and for supporting sustainable forest management at different scales. Recent technological advances, mainly regarding the availability of satellite data, remote sensing tools, machine learning, and online processing resources have provided new opportunities for forest monitoring.
Global and national forest monitoring capabilities are increasing fast. Moreover, stakeholders including research and academic institutions, service providers, space agencies, and government agencies have been involved in the development of novel approaches and techniques that can be used to support forest monitoring. This includes both organizations based outside tropical countries and those within.
Needs and Challenges for Forest Monitoring
Forest monitoring systems are primarily concerned with tracking forest area and area changes but also monitor variables related to forest welfare. One challenge is long-term monitoring of the structure and functioning of forests. This requires improving knowledge and information on the variety and distribution of species and changes in species composition in tropical forests. A better understanding of the impact on forest dynamics of drivers such as climate, disturbances, and interactions, is vital to foresee the future of forests. Integration of data sources can support monitoring efforts. For example, linking ground plots to Earth Observation (EO) information to evaluate forest biomass can support the assessment of carbon stocks and fluxes, and, hence, the forest reactions to anthropogenic alterations. Finally, data science can be useful for instance for modeling, which can provide insights into the dynamics of tropical forests associated with environmental conditions and disturbances. Although additional advances to eliminate significant systematic errors are needed, the application of correct statistical approaches is also a challenge to produce monitoring results. The challenges include the extraction of data from maps and uncertainty analysis.
Capacities for Forest Monitoring
Worldwide, there is a growing need for forest monitoring as well as increasing capacities for it. The needs for monitoring are mostly prompted by reporting requests for international policies but are also triggered by compliance with voluntary endeavors in the forest and land-use sector, forest certification programs, and the necessity to evaluate forest resources. Several countries have obtained assistance from international organizations in developing and improving their national forest monitoring systems. The capacities of countries for forest monitoring are varied and can be relatively
limited. The accessibility of remotely sensed data and tools by country is different, and there are disparities regarding the level of access to electricity, the internet, computer power, and software required for data access and analyses. In certain countries, the capacities, approaches, and methods need considerable enhancement prior to the accurate estimation of forest area and change. In these countries, there is a real need for efficient strategies to monitor the condition of forests, so that stronger management decisions and restoration endeavors can be employed. Nonetheless, the development of capacities in many countries is steadily increasing at a scientific, political, and functional level.
Identifying Research Challenges
The purpose of this study is to identify through a literature review the approaches and methods being used to monitor tropical forests. The aim is to also evaluate if those are being applied to the countries with the greatest needs for monitoring. Needs will be evaluated based on anthropogenic influences and disturbances. Consequently, reviewing the studies performed over the last years, in combination with the specific needs and challenges presented per country and their respective capacities, will contribute to the understanding of where research should be targeted in future ventures.
The study has three objectives.
- identify in literature research studies that address different forest monitoring challenges and the location where they are being applied.
- understand the relationship between the first authors and the location where the studies were performed.
- explore if there is a link between the location of studies and challenges faced by tropical countries in terms of forest changes and capacities for monitoring.
The anthropogenic impacts, and related needs for monitoring forests and forest change were evaluated using tree cover and biomass loss, as well as the carbon emissions and the burned area. Evaluating tree cover loss and biomass loss in tropical forests allows for the identification of deforestation, one of the most critical impacts. The release of carbon dioxide into the atmosphere, important for mitigation initiatives can be assessed through the above-ground biomass loss. Fires present challenges to monitoring forests, regarding their detection as dynamic events, and challenges in linking the burned area to biomass loss and estimating related emissions.
Forest Monitoring Capacities
The capacities for forest monitoring, and, thus, the need for research support, were evaluated using three indicators of forest monitoring (forest area change and RS capacity, forest inventory capacity, and carbon pool reporting capacity), access to the internet, and participation in REDD+ programs. The indicator for forest area change and RS capacity reveals the capacities of a country to monitor forest area, forest changes, and the country’s ability to produce maps using remotely sensed data. The indicator for forest inventory capacity concentrates on the country’s capacity to perform a national forest inventory. The indicator for carbon pool reporting capacity concentrates on the reporting of biomass and carbon stocks related to the carbon pools of forests: Above ground Biomass,
Below ground biomass, soil organic matter, deadwood, and litter. All indicators were used to classify the countries regarding their capacities for monitoring. Amazons will be justified.