Mangrove forests are found in sheltered coastal regions between 23.5 degrees north and south of the equator, especially where rivers deposit clay and silt. They contain salt-tolerant plants like Avicennia, Sonneratia, and Rhizophora trees that can reach up to 40 meters tall. These trees have specialized adaptations like prop roots, stilt roots, knee-like roots, and salt secreting or storing leaves to survive in the muddy, salty conditions.

1. Chapter 2
Mangrove Forests

2. In this lesson, you will understand:
• Where are Mangrove Forests found?
• What general characteristics do MF have?
• What special adaptations do MF have?

3. Distribution of Mangrove Forests
• Places that experience tropical climate i.e.
between 23.5ºN & S of Equator
• especially along sheltered coastal regions and
where rivers deposit clay and silt

4. Diversity of Mangrove Forests
• Halophytes (salt-tolerant plants) commonly found
– e.g. avicennia, sonneratia, rhizophora, bruguiera
– other plant species e.g. sea hibiscus, nipah palm

5. Density of Mangrove Forests
• High density due to high temperature & rainfall
• Sparse undergrowth due to dense canopy

6. Structure of Mangrove Forests
• 3 horizontal zones with trees about 15m tall
• Trees vary in height from 2m – 40m as muddy soil
in environment cannot provide firm support
High tide
Low tide
Coastal zone Middle zone Inland zone

7. Coastal Zone in Mangrove Forests
• Nearest to sea, flooded with saltwater at high
tides
• Trees have tube-like breathing roots
• e.g. avicennia species (pencil shaped)
• e.g. sonneratia species (peg shaped)

8. Middle Zone in Mangrove Forests
• Trees have prop or stilt roots growing from trunks
for anchoring plants firm to muddy soil
• e.g. rhizophora species

9. Inland Zone in Mangrove Forests
• Trees have knee-like roots to provide support on
soft soil
• e.g. bruguiera species that are least salt-tolerant

10. MF Special Characteristics: Leaves
• Evergreen, thick & leathery, broad
with drip tips
• Avicennia species are salt secretors
– excess salt secreted on leaves
and removed by wind or rain
• Bruguiera, Rhizophora and
Sonneratia species are
ultrafiltrators
– excess salt stored in old leaves
which then fall off

11. MF Special Characteristics:
Flowers and Fruits
• Generally colourful flowers to
attract insects for pollination
– e.g. Bruguiera species has
bright-red lantern flowers
• Buoyant fruits that are
dispersed by water
• Elongated fruits which
germinate while on parent tree
– e.g. Rhizophora species

12. 1 3
2 4

13. In this lesson, you have understood:
• Where are Mangrove Forests found?
• What general characteristics do MF have?
• What special adaptations do MF have?