Growth and architectural analyses of trees of agroforestry importance in Kerala.
Chandrashekara U. M.
Author Affiliation: Kerala Forest Research Institute, Peechi-680 653, Kerala, India.
Range Management & Agroforestry 18 : 151-163
Abstract : Characters such as crown architecture, growth and branching pattern were studied in 9 forest tree species (Ailanthus triphysa, Albizia odoratissima, Artocarpus hirsutus, Grewia tiliifolia, Macaranga peltata, Mangifera indica, Tectona grandis, Terminalia paniculata and Xylia xylocarpa) grown in home gardens in Panancherry Panchayat, Kerala (India), with a view to assessing their suitability as components in home garden agroforestry systems. The trees were each assigned to one of the architectural model types of Hallé (1978). Albizia and Xylia were assigned to the Troli model, and Grewia and Ailanthus to the Roux and Koriba models, respectively. Mangifera and Terminalia grown in the shade and in the open exhibited different architectural models, the Scarrone in shade conditions and the Leeuwenberg in the open. Artocarpus, Macaranga and Tectona were assigned to the Rauh model. Albizia, Grewia and Xylia exhibited a low and dome shaped crown in shade conditions in contrast to a narrow and conical crown in the open. On the other hand, Artocarpus, Macaranga, Mangifera, Tectona and Terminalia all had a tendency to develop a wider crown in the open and a narrow and conical crown in the shade. The growth and architectural characteristics of all the species are especially relevant in agrisilvicultural systems in which more shade demanding components are used. The study indicates that Albizia, Grewia and Xylia could be introduced in the early stages of perennial crop establishment as these species tend to grow straight with a narrow conical crown under less shade. In contrast, in the early stages of establishment of polyculture agroforestry systems, Artocarpus, Mangifera, Tectona and Terminalia may not be suitable as they tend to develop a wider crown in a relatively open area; however, when introduced into an established agroforestry system they may produce straight timber and less crown spread. The study also indicated that foliar phenology is important in determining appropriate crop mixtures. Some of the species studied (Tectona, Macaranga, Xylia, Terminalia and Grewia) are deciduous and leafless for 3-4 months; there is scope for cultivating light demanding short-duration crops under such trees.