Gavilán
Pentaclethra macroloba

Native Region
Central and South America
Max Height
25-35 meters
Family
Fabaceae
Conservation
LC
Uses
Distribution in Costa Rica
Legend
Elevation
0-700m
Regions
- Limón
- Heredia
- Alajuela
- Puntarenas
Season
Flowering
Feb-Mar
Fruiting
Apr-Jun
Gavilán
Gavilán (Pentaclethra macroloba), also known as Oil Bean Tree or Pracaxi in South America, is one of the most important—yet least celebrated—trees in Costa Rica's Caribbean lowland rainforests. This legume is often the dominant canopy tree in wet forest communities, where it performs the critical ecological function of nitrogen fixation, feeding nitrogen-poor tropical soils. With its explosive seed pods, distinctive compound leaves, and buttressed trunk, Gavilán shapes the structure and function of Caribbean rainforests. Understanding this tree is key to understanding how these magnificent forests work.
Quick Reference
- Scientific Name
- Pentaclethra macroloba
- Family
- Fabaceae (Legume Family)
- Maximum Height
- 25-35 m
- Trunk Diameter
- Up to 1 m
- Conservation
- Least Concern
- Key Feature
- Explosive pods; nitrogen fixer
iNaturalist Observations
Community-powered species data
2000
Observations
186
Observers
📸 Photo Gallery
Photos sourced from the iNaturalist citizen science database. View all observations →↗
Taxonomy and Classification
- Pentaclethra: Greek "pente" (five) + "kleithron" (bar) - reference to stamens - macroloba: Greek "makros" (large) + "lobos" (pod) - large pods - Family Fabaceae is the legume/bean family - Important nitrogen-fixing subfamily
Common Names
| Language/Region | Common Name(s) | Notes |
|---|---|---|
| Spanish (CR) | Gavilán | Standard name |
| Spanish | Quebracho | Regional |
| Spanish | Palo de Sangre | Blood wood - bark exudate |
| English | Oil Bean Tree | Oily seeds |
| English | Pracaxi | Brazilian/trade name |
| English | Wild Tamarind | General resemblance |
Related Species in Costa Rica
| Species | Common Name | Habitat |
|---|---|---|
| Inga spp. | Guabas (various) | Related nitrogen fixers |
| Samanea saman | Cenízaro | Dry forest legume |
| Enterolobium cyclocarpum | Guanacaste | Pacific legume |
| Dipteryx panamensis | Almendro | Another rainforest legume |
Physical Description
Overall Form
Gavilán is a medium to large canopy tree with a straight trunk, often developing prominent buttresses with age. The crown is rounded and dense, with the characteristic feathery appearance of compound-leaved legumes. It's notably one of the most abundant canopy trees in Caribbean lowland forests.
Identifying Features
The Explosive Pods
- Shape: Flat, curved, woody
- Size: 25-50 cm long!
- Color: Brown when mature
- Seeds: Large, flat, oily
- Action: EXPLOSIVE dehiscence!
- Sound: Loud cracking when pods open
- Dispersal: Seeds flung meters away
Bark and Trunk
- Bark color: Gray-brown, rough
- Texture: Fissured with age
- Inner bark: Reddish (bleeds)
- Buttresses: Well-developed, spreading
- Exudate: Dark red sap when cut
Leaves
- Type: Bipinnate compound
- Length: 20-40 cm
- Leaflets: Small, numerous (8-20 pairs per pinna)
- Pinnae: 10-20 pairs
- Texture: Delicate, feathery appearance
- Glands: Present on rachis
Flowers
- Type: Bottle-brush spikes
- Color: Cream to yellowish
- Size: Spikes 8-15 cm long
- Fragrance: Strongly scented
- Timing: Mainly dry season
Gavilán pods are famous for their violent dehiscence: The Explosion: - Pods dry and twist under tension - Suddenly CRACK open with loud sound - Seeds hurled up to 10+ meters! - Can startle hikers in the forest When It Happens: - Mainly dry season - Hot, sunny days - Often midday heat triggers opening Be Aware: - Seeds can sting if they hit you - Sounds like gunshot/branch breaking - One of the loudest seed dispersals This ballistic dispersal gets seeds away from the parent tree to avoid competition and disease!
Distribution and Habitat
Global Distribution
Geographic Distribution
Distribution in Costa Rica
| Province | Abundance | Notes |
|---|---|---|
| Limón | Dominant | Core habitat, often most common tree |
| Heredia | Common | Sarapiquí region |
| Alajuela | Common | San Carlos lowlands |
| Cartago | Present | Caribbean-facing slopes |
| Guanacaste | Rare | Only wettest areas |
| Puntarenas | Present | Osa Peninsula, Golfo Dulce |
Habitat Preferences
- Elevation: Sea level to 800 m (occasionally higher)
- Climate: Tropical wet to very wet
- Rainfall: 3,000-6,000+ mm/year
- Habitat: Primary and old secondary rainforest
- Light: Shade tolerant as juvenile, full sun as adult
- Soil: Tolerates nutrient-poor, acidic soils
- Topography: Lowland plains to lower slopes
Ecological Importance
The Nitrogen Fix
Keystone Nitrogen Fixer
Gavilán's most critical ecological function is nitrogen fixation: How It Works: - Root nodules harbor bacteria (Rhizobium and relatives) - Bacteria convert atmospheric N₂ to usable forms - Tree gets nitrogen, bacteria get sugars - Nitrogen enriches surrounding soil Why It Matters: - Tropical soils are often nitrogen-poor - Gavilán can add 40-100 kg N/ha/year! - Supports growth of neighboring trees - Enables high forest productivity Dominance Explained: - Self-sufficient nitrogen supply = competitive advantage - Can thrive where others struggle - Explains why it's often the most common tree In nutrient-poor tropical rainforests, Gavilán is essentially a fertilizer factory—fueling the entire ecosystem!
Wildlife Value
Seed and Pod Users
- Agoutis: Major seed predators and dispersers
- Peccaries: Eat fallen seeds
- Squirrels: Cache and consume
- Parrots: Eat developing seeds
- Monkeys: Consume young seeds
Other Ecological Roles
- Canopy structure: Major framework tree
- Microhabitat: Bark and branches host epiphytes
- Nutrient cycling: Leaf litter enriches soil
- Shade provision: Dense canopy creates understory
- Forest composition: Shapes plant community
Agoutis and Gavilán have an interesting relationship: The Interaction: - Agoutis eat many Gavilán seeds (predation) - BUT they also cache/bury seeds for later - Many cached seeds are forgotten - Forgotten seeds germinate Net Result: - Agoutis are both predators AND dispersers - They move seeds away from parent (good) - They bury seeds (good for germination) - Net effect: Beneficial to tree Conservation Link: - Where agoutis are hunted out, Gavilán regeneration suffers - Protecting agoutis = protecting forest composition This is why hunting can have cascading effects on forest tree populations!
Dominance in Caribbean Forests
In many Caribbean lowland rainforests, Gavilán is THE dominant tree: Abundance Data: - Can comprise 15-30% of all canopy trees - Often #1 in basal area (total trunk coverage) - Hundreds of individuals per hectare - Defines forest structure Why So Dominant?: 1. Nitrogen advantage: Makes own fertilizer 2. Shade tolerance: Seedlings survive understory 3. Longevity: Lives centuries if undisturbed 4. Aggressive dispersal: Explosive pods spread seeds Research Hub: - La Selva Biological Station: Gavilán is most-studied tree - Long-term demography plots track population - Model species for tropical forest dynamics Recognition Gap: Despite its importance, Gavilán is far less famous than trees like Ceiba or Guanacaste—but arguably more ecologically significant in wet forest ecosystems!
Uses
Limited Human Applications
| Use | Part | Notes |
|---|---|---|
| Local timber | Wood | Medium quality, local construction |
| Firewood | Wood | Common rural use |
| Traditional medicine | Bark | Various remedies |
| Seed oil | Seeds | Potential industrial interest |
| Ecosystem services | Whole tree | Primary value: nitrogen fixation |
The oil-rich seeds of Gavilán have attracted industrial interest: Pracaxi Oil (South American name): - Seeds contain 40-50% oil - Used in cosmetics and pharmaceuticals - Potential for sustainable harvest - Currently limited extraction in Brazil In Costa Rica: - Not commercially harvested - Research interest growing - Could provide forest income without logging The main value remains ecological services—nitrogen fixation and forest structure.
Cultivation
Growing Gavilán
Identification Guide
How to Identify Gavilán
Primary Identifiers:
- Large flat woody pods (25-50 cm!)
- Bipinnate leaves with many tiny leaflets
- Buttressed trunk base
- Red sap when bark cut ("blood wood")
Supporting Features:
- Caribbean wet forest habitat
- Often the most common large tree
- Cream bottle-brush flowers
- Explosive pod opening sounds
Where to See Gavilán in Costa Rica
| Location | Context | Notes |
|---|---|---|
| La Selva Biological Station | Research forest | Dominant species, well-marked |
| Tortuguero National Park | Lowland rainforest | Common throughout |
| Braulio Carrillo NP | Mountain to lowland | Lower elevations |
| Sarapiquí region | Various forests | Very common |
| Corcovado NP | Pacific wet forest | Present but less dominant |
In Caribbean wet forests, Gavilán is almost impossible to miss: Where to Look: - Any lowland Caribbean rainforest - Primary and older secondary forest - Look for buttressed trunks - Listen for exploding pods (dry season) Best Indicators: - Large flat pods on ground or tree - Bipinnate feathery leaves - Often the largest/most common tree Best Time: - Dry season: Pods and explosions - Year-round: Leaves and trunk visible At La Selva Biological Station, you literally can't walk 50 meters without passing a Gavilán!
Conservation and Research
Gavilán is one of the most intensively studied tropical trees: Research at La Selva: - Long-term demography studies (40+ years) - Nitrogen fixation rates measured - Seed dispersal and predation studied - Model for tropical tree population biology Key Findings: - Maintains dominance through shade tolerance - Nitrogen fixation varies with conditions - Hunting impacts regeneration (agouti loss) - Climate change may affect distribution Conservation Status: - Not globally threatened (wide range) - Locally dependent on intact forest - Sensitive to hunting of seed dispersers - Important indicator of forest health Gavilán teaches us how tropical forests work!
External Resources
Community observations and photos
Major research site
OTS research programs
References
📚 Scientific References & Further Reading
Hartshorn, G.S. & Hammel, B.E. (1994). Vegetation types and floristic patterns in La Selva. La Selva: Ecology and Natural History (eds. McDade et al.)
Guariguata, M.R. & Ostertag, R. (2001). Neotropical secondary forest succession. Forest Ecology and Management
Janzen, D.H. (1991). Historia Natural de Costa Rica. Editorial Universidad de Costa Rica
Walk through a Caribbean lowland rainforest in Costa Rica, and you're walking through Gavilán's domain. This tree—unremarkable to the casual eye, its name unknown to most visitors, its presence simply assumed—is quite possibly the most important organism in the forest. Deep in its roots, symbiotic bacteria are doing the impossible: pulling nitrogen from thin air and transforming it into the building blocks of life. That nitrogen flows outward: into leaves that fall and decay, into soil that feeds neighboring trees, into an ecosystem that couldn't maintain its lush productivity without this quiet engine of fertility. Above ground, Gavilán shapes the forest structure—its buttressed trunks and spreading crowns forming the framework within which countless other species live. And once a year, in the dry season's heat, the forest fills with sounds like distant gunfire: pods exploding, seeds hurtling through the air, the tree's aggressive claim on the future. Understanding Gavilán is understanding how tropical rainforests work—not through spectacular individual trees, but through the slow, persistent, vital processes that make everything else possible.



