Mr J. C. Delwaulle, Director of Centre Technique Forestier Tropical, Congo1, has kindly provided the below information regarding flowering and seed production of Pinus caribaea var. hondurensis, with particular reference to the article on the subject by C.M. Gallegos, published in Forest Genetic Resources Information no. 10 (1981) 2 3:
" - In the article by Dr Gallegos, which was based on a questionnarie distributed to countries in which the species is grown, it is stated that P. caribaea var. hondurensis generally does not produce viable seeds at low latitudes (9°N - 9°S). The only possible exceptions to this rule are reportedly Congo, Kenya and Tanzania in which, however, according to the article, the amounts of viable seeds produced are quite low.
" - The above information needs some modification as, at least in the case of Congo, it does not reflect the true situation. I would like to suggest that, in the interpretation of the data collected in the survey, not enough attention was paid to the varying climatic zones lying within the latitudinal belt in question.
" - The climate found in southern Congo is characterised by a very marked dry season of 4 – 5 months, and a mean annual rainfall of approximately 1200 mm. According to the climatic classification of Koeppen used in the above article, it corresponds to type Aw, rather than Am 4.
" - The flowering and seed production in Pinus caribaea var. hondurensis in Congo occur during the dry season. Considerable amounts of seed are produced in our plantations and seed orchards. In November 1980, the Unité d'Afforestation Industrielle du Congo (U.A.I.C.), established more than 1000 ha of pine plantations, using locally produced seed.
" - My interpretation of the results published in Forest Genetic Resources Information no. 10, is the following:
Pinus caribaea var. hondurensis will produce little or no viable seeds at low latitudes, in areas which correspond to Koeppen's climatic type Af. Examples of such areas are French Guiana, the Philippines, some areas in Brazil etc.
In areas, in which there is a marked dry season (Koeppen's climatic type Aw), Pinus caribaea var. hondurensis will flower and fruit normally. Examples of such areas are southern Congo, northern Nigeria, Uganda etc.
" - It is interesting to note that within its natural distribution range in Honduras, Pinus caribaea var. hondurensis occurs in climates of the type Aw.
" - To summarize, I am strongly of the opinion that climatic factors, rather than latitude per se, are limiting in the flowering and seed production of Pinus caribaea var. hondurensis.
We thank Mr Delwaulle for the information provided, which will contribute to our better understanding of this important plantation species.
1 B.P. 764, Pointe Noire, Congo
2 Gallegos, C.M. Flowering and seed production of Pinus caribaea var. hondurensis
(Preliminary results from a worldwide survey).
3 The points presented have been freely adapted from a letter on the subject received
from Mr Delwaulle in February 1982, and are thus not direct quotes.
4 See e.g. Koeppen, W. (1936). Handbuch de Klimatologie. Gebr. Borntraeger, Berlin.
