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How satellite data help evaluate forest condition and anticipate future risks

Lenka Foltýnová, Climate Resilience Specialist
Lenka Foltýnová
27/03/2026
  • Ecology
  • Greenery
  • UpGreen
Satellite data reveal forest productivity, stress, and survival capacity, enabling earlier detection of decline and better decisions under climate pressure.
Aerial view of a dense forest canopy, showing a mosaic of tree crowns in varying shades of green.
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Forest management is entering a new phase. The combination of climate pressure, budget constraints, and increasing expectations on ecosystem services is forcing a shift in how decisions are made. Field inspections remain essential, but they are inherently local, episodic, and often reactive. By the time visible symptoms appear, the underlying problem may already be well advanced. This is where satellite data begin to change the decision landscape.

Why assessing forest condition is getting harder

Forest condition has always been dynamic. But today, that variability is amplified by climate change.

Longer drought periods, higher temperatures, and more frequent extremes are affecting growth, vitality, and survival. At the same time, expectations on forests are increasing: production, biodiversity, carbon storage and water regulation.
forest

Traditional assessment approaches struggle in this environment for two main reasons:

  • First, field inventories provide comprehensive coverage, but they are periodic. This makes it difficult to detect gradual changes or early decline between inventory cycles.
  • Second, they are difficult to compare. Different observers, different timing, and different methods introduce variability that makes portfolio-level decisions harder to justify.

The result is a decision gap. Managers are often forced to prioritize based on partial information, intuition, or visible symptoms rather than underlying trends.

What satellite data can reveal about forest stands

“Satellite data address a different question than field inspections. They are not primarily about identifying individual trees or diagnosing specific pathogens. Their strength lies in observing patterns across space and time.”
Miloslav Kaláb, Climate Resilience Specialist
Miloslav Kaláb
ASITIS.cz, Climate Resilience Specialist

At a practical level, satellite-based forest condition monitoring can reveal:

  • Differences in vitality and productivity across stands
  • Survival capacity
  • Areas under increased drought stress
  • Spatial variability that would be difficult to detect from the ground
  • Changes in canopy condition over time
“These signals are typically derived from how vegetation reflects light, especially in parts of the spectrum linked to chlorophyll and water content. Satellites capture how active the vegetation is.
This activity is closely related to photosynthesis. “
Petr Klimeš, Climate Data Analyst
Petr Klimeš
ASITIS.cz, Climate Data Analysit, GIS analyst

Forest survival capacity

Satellite-based map showing a delineated urban green area analyzed using UpGreen methodology. The overlay visualizes spatial variation in tree condition across the area through three key indicators: survival capacity, productivity, and stress. Color-coded grid cells indicate: • Survival capacity, classifying trees as growing, stable, or declining based on their ability to persist under current conditions • Productivity, reflecting photosynthetic performance and vitality, from very high to none • Stress levels, capturing long-term environmental pressure such as heat, drought, and urban impact, from none to extreme The map highlights heterogeneity within the area, showing where trees are performing well, where they are stable, and where decline or elevated stress may require targeted intervention.
In applied analysis, forest survival capacity is not interpreted in isolation. It is understood as a combined signal of productivity, canopy density and stress exposure.

The key advantage is consistency. The same method can be applied across entire regions, allowing managers to compare stands objectively rather than relying on fragmented observations.

Survival capacity is addressing the future

Instead of asking:
“How does the forest look today?”
it allows you to ask:
“Can this forest maintain its function under current and future pressure?”
This distinction is critical for decision making.

A stand can appear stable today but still be structurally vulnerable. If productivity is weakening and stress is persistent, its ability to survive future droughts or heat waves is reduced. Conversely, a stand under temporary stress but with strong productivity may recover without intervention.

In practical terms, survival capacity helps you:

  • Identify stands that are approaching a tipping point
  • Distinguish between temporary stress and long-term decline
  • Prioritize areas where intervention will prevent future losses
  • Avoid unnecessary action in areas that are likely to remain stable

Using satelite data to calculate surival capacity answers the essential question, where will the forest hold, and where is it likely to fail?

Forest stress

When thinking about using satelite data for forest stress assessment, it is essential to think about it as a combination of multiple factors acting together:

– Drought pressure
– Heat exposure
– Site conditions


These factors do not act independently. Their effects accumulate. A tree can compensate for short-term stress. But when stress becomes persistent, it gradually reduces vitality, growth, and resilience.
Stress map of an urban green area analyzed using UpGreen, showing the spatial distribution of environmental pressure affecting trees. The color-coded grid represents stress intensity levels: • None to low stress (blue shades) indicates areas where trees experience relatively favorable conditions with sufficient water and lower heat or urban pressure • Medium stress (light orange) highlights transitional zones where trees begin to face limiting conditions • High stress (dark orange) marks areas under significant pressure, typically linked to heat exposure, drought, soil constraints, or proximity to infrastructure The map reveals a clear pattern: lower stress dominates the interior of the green area, while stress increases toward the edges and in localized hotspots. This suggests that boundary conditions such as surrounding urban surfaces, roads, or microclimate effects are driving higher stress levels.

Satellite data help capture this accumulation. Instead of identifying only visible damage, they reveal where pressure is building, often long before symptoms appear in the field.

This has direct management implications:

  • Areas with consistently high stress can be flagged for closer inspection
  • Repeated stress signals indicate structural problems, not temporary fluctuation
  • Spatial patterns reveal whether stress is localized or systematic across the landscape

For decision makers, stress maps answer a fundamental question: Where is the forest under pressure, even if it still looks green?

Forest Productivity

Productivity map of an urban green area analyzed using UpGreen, showing the spatial variation in tree performance and vitality based on photosynthetic activity. The color-coded grid reflects productivity levels: • Very high to high (dark green) indicates healthy, actively growing trees with strong ecosystem function • Moderate (light green) represents stable but not optimal performance • Low to very low (pink shades) highlights trees with reduced vitality and limited growth • None (red) marks areas with minimal or no functional productivity, such as heavily stressed, damaged, or missing trees The map shows that most of the area maintains moderate to high productivity, suggesting generally functioning vegetation. However, scattered clusters of low and very low productivity indicate localized decline or suboptimal conditions.
Productivity is one of the most informative signals in satellite-based forest analysis.

It reflects how effectively trees convert light, water, and carbon into growth. In other words, it shows how well the forest is functioning.

Low productivity is not just a visual issue. It has direct implications:
– Slower biomass accumulation and delayed value development
– Lower carbon sequestration
– Weaker cooling and water regulation functions
– Increased vulnerability to stress and disturbance

Importantly, productivity also acts as an early signal. A decline in productivity often appears before visible damage. Trees may still look green, but their internal performance is already weakening.

This makes productivity particularly useful for:

  • Detecting hidden decline
  • Comparing stands across large areas
  • Identifying zones where ecosystem function is already reduced
  • Supporting long-term investment and regeneration planning

Productivity helps answer a critical question: Is the forest still functioning, or is it gradually losing its growth potential?

From observation to decision

Stress, productivity, and survival capacity combined

Combined together, they create a powerful picture.

They allow you to see:
Where the forest is thriving
Where it is stable but under pressure
Where it is losing performance
Where it is at risk of future decline

This is the point where satellite data move from observation to decision support.

Instead of reacting to visible damage, forest managers can shift toward a more proactive approach by prioritizing inspections where early warning signals emerge, targeting interventions where they will have the greatest impact, allocating budgets based on measurable differences between stands, and communicating decisions with clear, data-based justification. The result is not more data, but better decisions under uncertainty.
Aerial view of a dense forest canopy, showing a mosaic of tree crowns in varying shades of green.

Where UpGreen Forest adds practical value

Satellite data provide the signals. But decision making requires structure, interpretation, and prioritization.

UpGreen Forest translates these signals into decision-ready outputs.

UpGreen forest evaluates stands combining:

– Productivity as a measure of functional performance
– Stress as a measure of environmental pressure
– Long-term trends as a measure of change
– Survival capacity as a measure of future risk

The result is a set of clear, actionable outputs:

  • Vitality and productivity maps
  • Forest stress maps
  • Survival capacity classification maps
  • A concise interpretation report

This allows forest owners, municipalities, and investors to move from scattered observations to systematic, portfolio-level management.

It is to make sure that attention, time, and resources are directed where they matter most.

The goal is not to replace field expertise.


Conclusion

If you want to understand how your forest is performing today and where it may be heading under future climate conditions, contact ASITIS to explore a pilot analysis or a tailored UpGreen Forest assessment.

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Lenka Foltýnová, Climate Resilience Specialist
Author of the article

Lenka Foltýnová

CEO společnosti ASITIS
Lenka Foltýnová holds a degree in mathematical biology with a focus on plant ecology and physiology. She earned her Ph.D. in Applied Bioclimatology. She works as a researcher in the field of climate change and the impact of the environment on plant physiological functions and their ecosystem services. In her work, she focuses primarily on woody plants and their species-specific responses to stressors typical of urban environments, such as drought, heat, and air and soil pollution. At Asitis, she is involved in developing methodologies for calculating and processing satellite data to assess the condition of urban greenery and evaluating the results within a broad environmental context.
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