In reference to the articles on the above subject published in Forest Genetic Resources Information numbers 10 and 11, Dr. F.S.P. Ng, Assistant Director of the Forest Research Institute at Kepong, Malaysia offers us the following observations 1:
"In Malaysia, it has been noted that Pinus caribaea seeds reliably only in plots located on sea coasts and on mountain slopes or ridges, where dependable winds and breezes develop during pollination (see: Razali & Ng, Malaysian Forester 42 (1979), page 73)2. The amounts of seed produced are, however, relatively low compared with figures reported from Queensland, Australia where observations on flowering and seed production have been made for a number of years; the reason may possibly be that the Malaysian plots are of sub-optimal size and shape for maximum seed production.
"For a wind pollinated species to reproduce, the species should occur at high stocking and occupy a relatively large area. A higher stocking results in larger volumes of pollen produced per unit area, increasing the probability of pollination of the ovules. At the same time, if the stand of trees occupies too small an area, pollen is easily blown out of the stand, hence there is a critical area below which a wind pollinated stand of trees cannot effectively reproduce. If the wind direction is relatively constant, the seed stand should have its long axis parallel to the direction of prevailing winds 3.
"In Malaysia, naturally occurring, wind pollinated species like Agathis, Dacrydium and Podocarpus are generally found on mountain summits, slopes and ridges, or on sea coasts (e.g. Casuarina, Podocarpus). Such habitats are more windy and relatively speaking, less species-rich (leading to higher number of individuals of the same species per unit area and, thus, potentially higher pollen yields; and less physical barriers in the form of other vegetation, obstructing the passage of wind-borne pollen).
"In the designing of seed stands in the tropics for wind pollinated species like pines we should, accordingly, draw a lesson from nature to optimize seed production.
“An interesting additional observation is that our pine plots on the coast and on mountain ridges also appear to produce a lot more strobili than in windstill locations. Perhaps wind also has the morpho-genetic effect of promoting the production of strobili?”
