GeospatialGeospatial

Detecting Deforestation with AI

How satellite monitoring and AI detect deforestation in real time. GLAD alerts, Global Forest Watch, and building your own detection pipeline.

Ryan Bethencourt
April 23, 2026
9 min read

The Scale of Deforestation

The world loses approximately 10 million hectares of forest every year – an area roughly the size of South Korea. Tropical deforestation accounts for the majority of this loss, driven by agricultural expansion, cattle ranching, logging, and infrastructure development. The Amazon, Congo Basin, and Southeast Asian rainforests experience the most severe pressure, with cascading effects on biodiversity, carbon emissions, and indigenous communities.

Monitoring deforestation at this scale is impossible with ground surveys alone. A single ranger station might oversee hundreds of thousands of hectares of forest, much of it accessible only by river or on foot. By the time illegal clearing is discovered through patrols, the forest is already gone. Satellite monitoring changes this equation fundamentally – every hectare of forest on Earth can be observed from space every few days, and AI can process these observations automatically to detect clearing within days of it occurring.

Note
Tropical deforestation and forest degradation account for approximately 8-10% of global greenhouse gas emissions. Reducing deforestation is one of the most cost-effective climate mitigation strategies available, but it requires knowing where and when clearing is happening in near real-time.

How Satellite Monitoring Works

Satellite-based deforestation monitoring relies on repeated observations of the same location over time. Each satellite image captures a snapshot of the forest canopy. By comparing images from different dates, analysts (and algorithms) can identify where forest has disappeared. The fundamental signal is simple: forest reflects strongly in the near-infrared spectrum, while bare soil and grassland do not. When a pixel transitions from high near-infrared reflectance to low, something has changed on the ground.

In practice, this simple concept encounters several complications:

  • Cloud cover: Tropical forests are cloudy for much of the year. A single Sentinel-2 image may have 50-80% cloud coverage, hiding the very deforestation you are trying to detect. Temporal compositing (combining multiple images over weeks) and SAR data (which sees through clouds) help mitigate this problem.
  • Seasonal variation: Deciduous forests naturally lose leaves seasonally, mimicking the spectral signature of deforestation. Models must distinguish seasonal phenology from actual clearing, typically by building a baseline of expected seasonal behavior for each pixel.
  • Degradation vs. clearing: Selective logging, fire damage, and canopy thinning are harder to detect than complete clearing because the spectral change is subtler. Radar data is more sensitive to structural changes in the canopy than optical data.
  • False positives: Cloud shadows, smoke from nearby fires, and sensor artifacts can be misidentified as forest loss. Machine learning models trained on confirmed deforestation events learn to filter these false signals.

AI Detection Methods

Change Detection

The most straightforward approach compares two images from different dates and flags pixels where vegetation indices have dropped below a threshold. NDVI differencing (subtracting the earlier NDVI from the later NDVI) highlights areas of vegetation loss. AI improves on simple thresholding by learning complex decision boundaries that account for seasonal patterns, sensor noise, and local ecosystem characteristics. Siamese neural networks, which process two images through identical network branches and compare the resulting features, have become the standard architecture for deep learning-based change detection.

Time Series Analysis

Rather than comparing just two dates, time series approaches analyze the full temporal trajectory of each pixel. Algorithms like BFAST (Breaks For Additive Season and Trend) decompose the signal into seasonal, trend, and residual components, then detect abrupt breaks in the trend that indicate deforestation. This approach is more robust to seasonal variation and gradual degradation than two-date comparison. Deep learning variants use recurrent neural networks (LSTMs) or temporal convolution networks to learn temporal patterns from labeled deforestation time series.

Spatial Pattern Recognition

Deforestation often follows recognizable spatial patterns: fishbone patterns along roads in the Amazon, concentric clearing around settlements in the Congo Basin, or systematic plantation establishment in Borneo. Convolutional neural networks learn these spatial patterns from labeled examples, enabling them to detect deforestation even before the spectral change is fully visible. This spatial context helps distinguish planned agricultural expansion from natural disturbances like windthrow or flooding.

Existing Monitoring Systems

GLAD Alerts

The Global Land Analysis and Discovery lab at the University of Maryland produces weekly deforestation alerts from Landsat imagery. GLAD alerts have been the backbone of tropical forest monitoring since 2016, providing publicly accessible, near-real-time alerts at 30-meter resolution. The system processes every new Landsat scene automatically, applying a trained classifier to detect tree cover loss and issuing alerts through the Global Forest Watch platform.

Global Forest Watch

Global Forest Watch (GFW) is a platform built by the World Resources Institute that aggregates multiple deforestation monitoring systems into a single interactive map. It combines GLAD alerts, Hansen tree cover loss data, fire alerts (VIIRS and MODIS), and integrated deforestation alerts (combining optical and radar data) into a comprehensive monitoring dashboard. GFW provides free data access, email alerts for custom areas of interest, and an API for programmatic access.

Tip
You can set up custom alert areas on Global Forest Watch to receive email notifications whenever deforestation is detected within your area of interest. This is useful for NGOs monitoring specific conservation areas, companies tracking deforestation in their supply chains, and journalists investigating illegal clearing.

Deforestation Analysis via API

SciRouter's geospatial endpoints enable programmatic deforestation monitoring. Here is how to check for forest loss in a specific region:

Detect deforestation with satellite AI
import requests

API_KEY = "sk-sci-your-api-key"
BASE = "https://api.scirouter.ai/v1"
HEADERS = {"Authorization": f"Bearer {API_KEY}"}

# Monitor a region in the Amazon for deforestation
response = requests.post(f"{BASE}/geospatial/change-detect",
    headers=HEADERS,
    json={
        "latitude": -3.47,
        "longitude": -62.22,
        "radius_km": 25,
        "source": "sentinel-2",
        "date_before": "2025-06-01",
        "date_after": "2026-03-01",
        "change_type": "deforestation",
        "min_area_ha": 1.0
    })

result = response.json()
print(f"Region analyzed: {result['area_km2']:.0f} km2")
print(f"Forest cover (before): {result['forest_pct_before']:.1f}%")
print(f"Forest cover (after):  {result['forest_pct_after']:.1f}%")
print(f"Forest loss detected:  {result['loss_ha']:.1f} ha")
print(f"Loss hotspots: {len(result['hotspots'])}")
for h in result["hotspots"][:5]:
    print(f"  ({h['lat']:.4f}, {h['lon']:.4f}) - {h['area_ha']:.1f} ha")
Output
Region analyzed: 1963 km2
Forest cover (before): 87.3%
Forest cover (after):  84.1%
Forest loss detected:  628.4 ha
Loss hotspots: 23
  (-3.4212, -62.1847) - 142.3 ha
  (-3.5103, -62.3021) - 87.6 ha
  (-3.3876, -62.1543) - 64.2 ha
  (-3.4921, -62.2765) - 51.8 ha
  (-3.4456, -62.1932) - 43.1 ha

Building a Deforestation Alert Pipeline

For continuous monitoring, you can set up a pipeline that runs periodically and sends alerts when new deforestation is detected:

Automated deforestation alert pipeline
import requests
from datetime import datetime, timedelta

API_KEY = "sk-sci-your-api-key"
BASE = "https://api.scirouter.ai/v1"
HEADERS = {"Authorization": f"Bearer {API_KEY}"}

# Define monitoring areas (protected forests, supply chain regions)
watch_areas = [
    {"name": "Xingu Indigenous Park", "lat": -11.5, "lon": -53.0, "radius": 50},
    {"name": "Tapajós National Forest", "lat": -4.0, "lon": -55.0, "radius": 30},
]

today = datetime.now()
two_weeks_ago = today - timedelta(days=14)

for area in watch_areas:
    response = requests.post(f"{BASE}/geospatial/change-detect",
        headers=HEADERS,
        json={
            "latitude": area["lat"],
            "longitude": area["lon"],
            "radius_km": area["radius"],
            "source": "sentinel-2",
            "date_before": two_weeks_ago.strftime("%Y-%m-%d"),
            "date_after": today.strftime("%Y-%m-%d"),
            "change_type": "deforestation",
            "min_area_ha": 0.5
        })
    result = response.json()
    if result["loss_ha"] > 0:
        print(f"ALERT: {area['name']} - {result['loss_ha']:.1f} ha lost")

From Detection to Action

Detecting deforestation is only valuable if it leads to intervention. The most effective monitoring systems connect satellite detections to enforcement agencies, supply chain compliance teams, and conservation organizations through automated alert pipelines. Here is how different stakeholders use deforestation intelligence:

  • Law enforcement: Real-time alerts direct ranger patrols to active clearing sites, enabling intervention before large areas are lost.
  • Supply chain compliance: Companies committed to zero-deforestation supply chains monitor their sourcing regions and flag suppliers operating in recently deforested areas.
  • Carbon markets: Forest carbon credit projects use satellite monitoring to verify that protected forests remain intact, providing the measurement and verification layer that carbon credits require.
  • Research: Scientists use long-term deforestation records to study the relationship between forest loss, climate change, biodiversity decline, and human development.

Next Steps

To explore satellite-based environmental monitoring further:

Every day that deforestation goes undetected is a day of irreversible loss. AI-powered satellite monitoring makes detection faster, cheaper, and more comprehensive than ever before. Get a free API key and start monitoring the forests that matter to you.

Frequently Asked Questions

How does AI detect deforestation from satellite images?

AI detects deforestation by comparing satellite images from different dates and identifying areas where forest has been replaced by bare soil, grassland, or agriculture. The most common approach uses change detection algorithms that analyze pixel-level differences in vegetation indices (like NDVI) between two time periods. Deep learning models improve on this by learning to distinguish real deforestation from seasonal changes, cloud shadows, and sensor noise. Some systems combine optical imagery (which shows vegetation color) with radar imagery (which penetrates clouds and detects structural changes in the canopy).

What are GLAD alerts and how do they work?

GLAD (Global Land Analysis and Discovery) alerts are a near-real-time deforestation monitoring system developed at the University of Maryland. The system processes every new Landsat image as it becomes available (approximately every 8 days for any location) and flags pixels where tree cover loss is detected. GLAD uses a decision-tree classification algorithm trained on known deforestation events. When a pixel transitions from forest to non-forest, an alert is issued with the date, location, and confidence level. Alerts are publicly available through Global Forest Watch and can be accessed via API.

How quickly can satellite AI detect deforestation?

Detection speed depends on satellite revisit frequency and cloud cover. With Sentinel-2 (5-day revisit) and Landsat (8-day revisit combined), deforestation in cloud-free conditions can be detected within 5-10 days. In tropical regions where persistent cloud cover is common, detection may take 2-4 weeks. SAR satellites like Sentinel-1 can detect canopy loss through clouds, reducing latency to 6-12 days regardless of weather. The fastest commercial systems achieve near-daily detection by combining multiple satellite constellations, though these require paid data access.

Can AI distinguish legal logging from illegal deforestation?

AI can identify spatial patterns associated with different types of forest clearing. Legal logging concessions typically show planned road networks and systematic clearing patterns, while illegal deforestation often appears as irregular patches extending from rivers or unofficial roads into intact forest. However, determining legality ultimately requires cross-referencing satellite detections with land use permits, concession boundaries, and protected area maps. AI can flag suspicious patterns for investigation, but the legal determination requires additional context that satellites alone cannot provide.

What satellite data sources are available for deforestation monitoring?

Several free satellite constellations provide data suitable for deforestation monitoring. Landsat (USGS/NASA) has the longest continuous record, dating back to 1972, with 30-meter resolution and 16-day revisit. Sentinel-2 (ESA) provides 10-meter resolution with 5-day revisit since 2015. Sentinel-1 (ESA) provides radar data through clouds at approximately 10-meter resolution. MODIS provides daily global coverage at 250-meter resolution, useful for detecting large-scale clearing. For higher resolution, commercial providers like Planet offer daily 3-meter imagery, and Maxar provides sub-meter resolution for detailed investigation.

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