Detailed studies have not been made elsewhere, and those summarized above are mostly only on one or a
few populations. The generalization which emerges from these fragmentary observations is that Agathis
populations with a range of size classes Le. which are apparently self perpetuating are restricted to 'poor'
sites throughout Malesia and only in the islands of the south west Pacific do they occur on normal zonal soils.
It may be no coincidence that compared to Malesia the rain forests of Santa Cruz, New Hebrides and New
Caledonia are poor in species. It remains a mystery how the isolated trees and small groups of large
Agathis trees on zonal soils in the Malesian rain forests reproduce themselves.