EARLY GROWTH OF A MIXED QUERCUS, CORNUS, ALNUS AND CUPRESSUS PLANTATION IN COSTA-RICA

The growth of an eleven year old, mixed plantation of four native tree species (Quercus seemannii, e. pilarius, Cornus disciflora and Alnus acuminata) and an exotic species (Cupressus lusitanica) was studied in San Jose de la Montana, Heredia, Costa Rica. C. lusitanica had the la rgest diameter (23.46 cm), and A. acuminata, the greatest height (22.0 8 m). Q. pilarius had the lowest diameter growth rate (0.52 cm/yr), C. lusitanica showed the highest diameter growth rate (2.13 cm/yr) while C. disciflora had a medium growth rate (1.28 cm/yr). The best archite ctural qualities were seen in A. acuminata and C. lusitanica, followed by C. disciflora. Growth and architectural data show that light intol erant species A. acuminata and C. lusitanica grow well in mixed planta tions. Slower growing oaks, known as tolerant species, need more light . Thinning operations around or before age seven are recommended, espe cially to improve growth of Quercus species.