Ficus kerkhovenii or Johore Fig as nicknamed by Corner is both the largest and most variable strangler in Bornean lowland forests, widespread from the coast to the hills where original forest remains intact.
F. kerkhovenii is a true strangler which has evolved to gain access to sunlight in the canopy by starting growth as an epiphyte on a tall forest host tree, then dropping down aerial roots to the ground. Once the aerial roots are strong enough to support the fig tree, the host tree is then strangled to death and rots away leaving the strangler in full sunlight above the canopy.
According to Rhett Harrison (2003) at Lambir NP in Sarawak Ficus kerkhovenii was the most common large strangler in his 120 ha study plot with 22 adult individuals present of which 6 were already free standing.
“Ficus kerkhovenii usually produces three massive aerial roots on different sides of its host, and then a band (collar) connecting them immediately below the point of attachment constricts the host. Actual strangulation takes just a few months.”
Once the aerial roots of Ficus kerkhovenii reach the ground they fork producing” knees” and mini tripod structures around the base of the fig providing multiple structural supports and elevating (pushing up) the top of the fig tree crown above canopy level, so that the fig tree becomes a dominant emergent above the forest canopy.
The photos and links in this article show by example that F. kerkhovenii roots are extremely versatile with a number of unusual features including;
- Elevator roots which can expand in length to gain canopy height and therefore dominance
- Tripod structures replicated at different scales for structural support.
- Constriction collars to rapidly kill the host which can be turned on and off.
- Constriction roots which which can tension aerial roots to provide structural support.
