Periodicidad del clima y del crecimiento de especies forestales en Turrialba, Costa Rica

Abstract

Through frequent periodical mesurements of trees in the Turrialba, Costa Rica, area, it was shown that some trees grow in yearly cycles or periods. For decidious trees there are 6 months of growth and 6 months of rest; for evergreens there are 6 months of low growth and 6 months of high growth. This seems to be the pattern of growth in trees of the northern hemisphere, wich coincide closedy with the periodicity of the values of some climatic elements, such as absolute minimun and maximun temperatures, absolute minimun relative humidity, number of days with rain over 3 mm. daily and day-length. Hours of sunshine have an inverse periodicity because the period of lower values coincides with the period of higher growth. Rain showed a relative coincidence; it displayed positive correlations for monthly periods but for yearly periods, the correlation became negative. The growth pattern of Eucalyptus saligna, failed to show consistent correlation with climatic elements. Those minimun values of the climatic elements which showed the higheest positive correlations with tree growth maybe considered as limiting factors. They are minimun temperature of 10-12 ðC or below (average of 6 months period), less than 9 days of rain per month and the relative humidity of 44-46 per cent or below. Calculated correlations between growth and climatic elements in different periods were higher and positive when these periods coincided, higher and negative when these periods coincided inversely and lower and no significant when no clear coincidence of periods was found. It is supossed that adaptability means coincidence of growth with favorable values of climatic elements