Discussion of the plenum with P. Kageyama:

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C. Palmberg-Lerche: Even rare, tropical species have been found to be outbreeding, to a very large extent, which is surprising. See e.g recent publications of Bawa (USA).

C. Palmberg-Lerche: FAO has over the past years carried out a study on mixed and pure plantations. There is a very great scarcity of scientific studies and information on this issue, however, one thing is clear: mixed planting is not a question of just mixing a number of species and throwing them out in the forest; it pre-supposes thorough knowledge of the species concerned and intensive management, based on solid knowledge of phonology and of the species involved, and their interactions. Very complex.

P. Krutzsch: Genetic consequences when collecting seed from wide spread individuals of rare species?

P. Kageyama: Some unkown (no studies) mechanism to counteract.

B. Krishnaypillay: Rare species have irregular seedling patterns. How do you go about monitoring these species so that seed collections from these species are not used?

P. Kageyama: The trees are marked and regularly monitored (phenologaical studies are carried out regularly). Hence seeds from all these species are carefully collected. There is no problem on this matter.

G. Sykes: Does the composition of "Seed Packages" change to reflect different site conditions?

P. Kageyama: Only one "Package" is being used at this time. Pioneer species are growing well on a variety of sites but climax species will be more site specific.

K. Kilpatrick: I would like to complement. This is very timely and can apply to African forestry very well.

- How was original deforestation accomplished?
- So are sources second growth or?

P. Kageyama: Original deforestation was due to coffee plantations and ranches etc., but there are plenty of small blocks of natural forest left so this is where the genetic research is going on and these are the sources for their seeds as well.

F. Esegu: What explanation do you give for pioneer species to have low genetic variation within populations and climax species have high genetic variation within populations.

P. Kageyama: Pioneer species occur in gaps with restricted populations thus restricted gene flow; therefore low genetic variation within populations. Climax species occur in continuous large populations thus high rate of gene flow within a population; therefore high genetic variation within populations.

G. Bonnis: What is the cost of the mixed plantation proposed in Brazil?

P. Kageyama: Cost is around US$ 300/ha, of which 50% is for seedling production.

J. Okonya: What steps is the country taking to make sure that past mistakes that have proved so expensive to redress forest destruction, are reduced and stopped altogether?

P. Kageyama: Good registration. Social pressure groups for environment protection; development projects planting forests as an input towards environmental protection; individual states raising up riperian forests.

D. Rudin: Why are the rare species rare? Natural selection or human interference?

P. Kageyama: Mostly natural selection, e.g. through insects attacking the seeds. Human interference in rare cases.