Abstract:
The growth of Alnus acuminata (HBK) 0. Ktze, Cupressus
lusitanica Mill., Gmelina arborea Roxb, Pinus caribaea var. hondurensis
Barr. & Golf., and Tectona grandis L. in Costa Rica and
twenty seven soil and climatic factors were analyzed to determine
the relationship between major environmental factors and growth
rates of these five species. The growth of the species was compared
within specific climatic zones of Costa Rica, and in the country as
a whole. A reduced set of environmental factors was selected that
best explains the species growth in the country and in specific
geographic zones.
The forestry plots used in this study were installed by the
Forest Service of Costa Rica, complemented with a few private
farmer plantations. Diameter at breast heigh (dbh), the height,
and volume growth of the trees were used as dependent variables.
Data for twelve climatic variables were obtained from the national
meteorological stations. Fifteen soil characteristics were evaluated
for each study site.
The growth of Alnus was found to be related to relative
humidity, the distribution of precipitation and the percentage soil
base saturation. Within the range evaluated (78-80%) an increase
in the mean annual relative humidity will depress growth of this
species.
For Cupressus it was found that soil texture (% silt content),
altitude of the plots, soil base saturation, as well as cation
exchange capacity and nitrogen in the Central Valley of Costa Rica,
were the environmental factors most closely related to the growth
of this species. For the altitudinal range evaluated (1100-2620 ta)
a decrease in growth can be expected as altitude increases.
Growth of Gmelina was found to be closely related to soil
characteristics: available phosphorus, exchangeable sodium and
potassium, cation exchange capacity and organic matter The
genera]. observation from this regression analysis and experience
in other countries is that Gmelina requires fertile soils and
favorable physical properties for optimum growth. However, this
species is growing satisfactorily in all areas below 500 meters of
elevation in Costa Rica; no data is available above this elevation.
Amount and distribution of precipitation, exchangeable potassium,
magnesium, and sodium, soil texture, and an energy factor
(number of hours of light and radiation, or interaction of these
two variables) were the factors most closely related to the growth
of P. caribaea in the country.
For Tectona it was found that soil texture, temperature, and
exchangeable potassium, calcium, and sodium were the factors most
closely related to the growth of this tree in Costa Rica,
The information developed in this study provides a better
basis for understanding the growth requirements of these five
species. However, planting guidelines must await the inclusion of
additional data into the analysis.
