Learn about mangroves

Feature · Field guide

What mangroves are, why Himamaylan needs them, how to recognise each species, and how you can help.

From the City ENRO · 16 species · 6 short chapters · a 10-question quiz

Photo: ENRO field report, Himamaylan

Chapter I

What is a mangrove?

Mangroves are trees and shrubs that grow along coasts and river mouths, in salty or brackish water that floods and drains with the tide twice a day. Few plants can survive there: the soil is salty, soft, and has almost no air.

"Mangrove" is the name of these plants and of the forest they form together. In Himamaylan they line the coast and the river mouths of the coastal barangays, a green belt between the sea and the town.

Chapter II

Why they matter

A healthy mangrove forest works for the whole city, every day, for free.

Storm protection: Trunks and roots slow down waves and storm surge before they reach homes.
Fish nursery: Young fish, shrimp and crabs hide and feed among the roots. Good mangroves mean better catches.
Clean water: Roots trap mud and pollution coming down the rivers, protecting seagrass and reefs.
Climate: Mangroves store large amounts of carbon ("blue carbon") in their mud for centuries.
Livelihood: Nipa roofing, vinegar, honey, shellfish gathering and eco-tourism.

“A wide belt of mangroves is the first wall a storm meets, and the cheapest one a city can have.”

Chapter III

How they survive

Life in salty, airless mud needs special tools. Look closely at the roots and you can often tell the species before you see a single leaf.

Prop roots Bakhaw. Arching "legs" that hold the tree in soft mud.

Breathing roots Bungalon, Pagatpat. Pencils poking out of the mud to take in air.

Knee roots Busain. Loops that bend up out of the mud like knees.

Salt control. Some species keep salt out at the roots (Bakhaw); others push it out through their leaves (Bungalon, Saging-saging). On a dry day you can see tiny salt crystals on a Bungalon leaf.

Living seeds. Bakhaw seeds sprout while still on the tree. The long, pencil-like propagule drops into the mud, ready to root within days.

Chapter IV

Who grows where

Walk from the sea toward the land and the forest changes. Each species grows best at a certain height on the shore, depending on how often the tide covers it and how salty the water is.

Fig. 1 The mangrove zones, from the sea to the land. Nipa grows along brackish rivers.

This is why the right species in the right zone is the secret of a planting that survives.

Chapter V

What harms them

Conversion of mangrove areas into fishponds, salt beds, housing or roads.
Cutting for firewood, charcoal and posts.
Garbage. Plastic caught among the roots smothers breathing roots and young trees.
Pollution and siltation from rivers; oil and chemicals.
The wrong species in the wrong place, for example on seagrass beds or mudflats that are naturally bare, where seedlings die.
Storms and rising seas, which healthy, wide mangrove belts withstand far better.

The Philippines has lost about half of its mangrove forests in the last century, mostly to fishponds and cutting.

Chapter VI

How you can help

Do not cut mangroves, and do not buy mangrove charcoal or posts.
Keep garbage out of rivers and the coast; join coastal clean-ups.
Join ENRO planting activities rather than planting on your own: ENRO picks the right species and spot so seedlings survive.
Report cutting, dumping or filling of mangrove areas to the City ENRO.
Share what you learn with family, classmates and neighbours.

Mangroves are protected by national law: cutting them without a permit and converting mangrove areas into fishponds or other uses are prohibited (for example under the Philippine Fisheries Code, RA 8550 as amended by RA 10654). Ask the City ENRO about local rules.

Part two

The field guide: 16 species

Open a plate to see how to recognise the tree. A green pin means ENRO has recorded it in Himamaylan.

Search species Root type Seen in Himamaylan only

Plate 1 Bakhaw lalaki Rhizophora apiculata Prop (stilt) roots

How to recognise it: Arching stilt roots hold the tree up like legs. Leaves are smooth, elliptic, with a short sharp point at the tip.
Flowers and fruit: Small cream flowers in pairs on a short, thick stalk. The long, pencil-like propagule hangs from the tree.
Where it grows: Middle zone, muddy banks and creeks
Quick tip: Pairs of flowers + pointed leaf tip = Bakhaw lalaki.
Good to know: Most planted species in community reforestation; strong wood for posts (cutting is regulated).
Family: Rhizophoraceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 2 Bakhaw babae Rhizophora mucronata Prop (stilt) roots

How to recognise it: Big arching stilt roots. Leaves are broad, with a tiny spike (mucro) at the very tip.
Flowers and fruit: Flowers in clusters of 4 or more on long stalks. Propagules are long, heavy and warty.
Where it grows: Middle zone, soft deep mud along rivers
Quick tip: Clusters of flowers and a broader leaf than Bakhaw lalaki.
Good to know: Widely planted on muddy river banks; propagules root quickly.
Family: Rhizophoraceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 3 Bakhaw bato Rhizophora stylosa Prop (stilt) roots

How to recognise it: Dense prop roots and often spotted bark. Looks like the other Bakhaw.
Flowers and fruit: Flowers have a long style (the thin stalk in the middle of the flower), which gives the name "stylosa".
Where it grows: Sandy or coral (rocky) shores
Quick tip: Bakhaw growing on sand or coral rubble is often Bakhaw bato ("bato" = stone).
Good to know: Good for planting on sandy, rocky shores where other Bakhaw struggle.
Family: Rhizophoraceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 4

Bungalon Avicennia marina Pencil-like breathing roots (pneumatophores) Recorded in Himamaylan (1)

How to recognise it: Hundreds of pencil-like roots stick up from the mud around the tree. Leaves are grey-green above and silvery-white below; you can sometimes see salt crystals on them.
Flowers and fruit: Small orange-yellow flowers. Flattened, bean-like fruits.
Where it grows: Seaward edge; pioneer on new mudflats
Quick tip: Silvery leaf underside + salt on the leaves = Bungalon.
Good to know: Very salt-tolerant; often the first tree to colonise new mud, holding it in place.
Family: Acanthaceae
In Himamaylan: 1 published or expert-confirmed record(s).

Plate 5 Api-api Avicennia officinalis Pencil-like breathing roots (pneumatophores)

How to recognise it: Pencil roots like Bungalon, but leaves are broader with a rounded tip and dull, yellowish-green underside.
Flowers and fruit: Larger golden-yellow flowers; heart-shaped fruit with a short beak.
Where it grows: Riverbanks and middle zone
Quick tip: Rounded, broad leaves with pencil roots.
Good to know: Stabilises river banks with its dense root mat.
Family: Acanthaceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 6 Miapi Avicennia rumphiana Pencil-like breathing roots (pneumatophores)

How to recognise it: Leaves have a rusty-brown, hairy underside that you can feel with your fingers.
Flowers and fruit: Small yellow-orange flowers.
Where it grows: Middle zone
Quick tip: Feel the leaf underside: soft, brown hairs = Miapi.
Good to know: Listed as Vulnerable worldwide (IUCN): every tree matters.
Family: Acanthaceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 7 Pagatpat Sonneratia alba Thick cone-shaped breathing roots

How to recognise it: Thick cone-shaped roots rise from the mud. Leaves are rounded and thick.
Flowers and fruit: White powder-puff flowers that open at night and are visited by bats and moths. Round fruit sitting on a star-shaped base.
Where it grows: Seaward edge, often with Bungalon
Quick tip: Star-shaped base under a round green fruit = Pagatpat.
Good to know: Fireflies often gather on Pagatpat trees at night.
Family: Lythraceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 8 Busain Bruguiera gymnorhiza Knee roots and buttresses

How to recognise it: Roots loop up out of the mud like bent knees. Large, leathery leaves.
Flowers and fruit: Big red flowers with many pointed lobes; cigar-shaped propagules.
Where it grows: Inner (landward) zone, firmer mud
Quick tip: Red, star-like flower cup + knee roots = Busain.
Good to know: Hard, durable wood; the red flower cups are easy to spot.
Family: Rhizophoraceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 9 Pototan babae Bruguiera cylindrica Knee roots

How to recognise it: Slender tree with small knee roots.
Flowers and fruit: Small greenish-white flowers; thin, slightly curved propagules.
Where it grows: Middle to inner zone
Quick tip: Like a small Busain with pale flowers.
Good to know: Grows on firm mud that is flooded less often.
Family: Rhizophoraceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 10 Tangal Ceriops tagal Short stilt roots, buttressed base

How to recognise it: Small tree or shrub. Shiny, rounded leaves crowded at the ends of branches.
Flowers and fruit: Small white flowers; slender, ribbed propagules.
Where it grows: Inner zone, firm mud
Quick tip: Ribbed propagule + rounded shiny leaves = Tangal.
Good to know: The bark was traditionally used for tannin and dye.
Family: Rhizophoraceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 11 Tabigi Xylocarpus granatum Wavy plank (snake) roots

How to recognise it: Ribbon-like roots snake across the ground. Compound leaves (several leaflets on one stalk).
Flowers and fruit: Large round brown fruit, like a cannonball, holding big irregular seeds.
Where it grows: Inner (landward) zone
Quick tip: Cannonball fruit = Tabigi.
Good to know: Related to mahogany; valued wood.
Family: Meliaceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 12 Tabao Lumnitzera racemosa No visible aerial roots

How to recognise it: Shrub or small tree. Fleshy, spoon-shaped leaves with a small notch at the tip.
Flowers and fruit: Small white flowers in short spikes.
Where it grows: Landward edge, rarely flooded
Quick tip: Fleshy spoon-shaped leaves, no aerial roots.
Good to know: Marks the inland edge of the mangrove forest.
Family: Combretaceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 13 Lipata Excoecaria agallocha Surface roots

How to recognise it: Tree with smooth bark and alternate leaves. Breaking a leaf releases white milky sap.
Flowers and fruit: Small flowers on catkin-like spikes.
Where it grows: Landward edge
Quick tip: Milky sap = Lipata. Keep the sap away from your eyes: it can cause temporary blindness ("buta-buta").
Good to know: An important part of the inner forest; handle with care.
Family: Euphorbiaceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 14

Nipa Nypa fruticans Underground stem (no trunk) Recorded in Himamaylan (7)

How to recognise it: A palm with no trunk above the ground: long fronds grow straight up from the mud.
Flowers and fruit: A large round head of fruits at the base of the fronds.
Where it grows: Brackish rivers and estuaries
Quick tip: A trunkless palm in brackish water = Nipa.
Good to know: Leaves for "pawod" roofing; sap for vinegar and tuba.
Family: Arecaceae (palm)
In Himamaylan: 7 published or expert-confirmed record(s) in Brgy. Caradio-an, Brgy. Barangay II (Poblacion), Brgy. Talaban.

Plate 15 Saging-saging Aegiceras corniculatum No aerial roots

How to recognise it: Shrub with leathery leaves that may show salt crystals.
Flowers and fruit: Fragrant white flowers; curved, horn-shaped fruits that look like tiny bananas.
Where it grows: River banks, middle zone
Quick tip: Tiny banana-shaped fruits = Saging-saging.
Good to know: Flowers attract bees; often grows at the water edge of rivers.
Family: Primulaceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Plate 16 Nilad Scyphiphora hydrophyllacea No aerial roots

How to recognise it: Shrub with glossy, opposite leaves.
Flowers and fruit: Small white or pinkish flowers; small ribbed fruits.
Where it grows: Inner zone, sandy mud
Quick tip: Glossy shrub of the inner zone.
Good to know: Manila ("may nilad") is said to be named after this plant.
Family: Rubiaceae
In Himamaylan: Not yet in published reports. ENRO adds records as surveys are reviewed.

Part three

Test yourself

Ten questions. Each answer is explained.

Glossary

Words to know

Propagule: A seedling that starts growing while still on the parent tree, then drops and roots in the mud.
Pneumatophore: A "breathing root" that grows up out of the mud to take in air.
Prop root: A root that arches from the trunk into the mud, holding the tree up.
Knee root: A root that loops up out of the mud like a bent knee.
Brackish water: A mix of fresh river water and salty sea water.
Estuary: The wide mouth of a river where it meets the sea.
Intertidal zone: Shore that is under water at high tide and dry at low tide.
Zonation: Bands of different species from the sea to the land.
Canopy cover: How much ground the tree crowns cover, seen from above. MangroVision measures it from drone images.
Blue carbon: Carbon stored by coastal ecosystems, mostly in their soil.
Reforestation: Planting trees where a forest used to be; for mangroves, where they grew before.
Siltation: Mud and sand settling from rivers; too much buries roots and seedlings.

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