Seasonality in this part of the world is marked by differences in rainfall, with a dry season occurring during the months of our northern winter. The climatic factors which create these tropical seasons also account for features on observes in the vegetation. In the San Jose vicinity, tall Erythrina trees were covered with pink-orange blooms on otherwise bare branches. Limbs of the other trees covered with a thick blanket of epiphytes were not lush green but brownish, waiting for the reviving rains to come in several weeks. Lushness dominates the surrounding slopes, which are evergreen, some moisture being constantly supplied to those heights throughout the year from the ever-present clouds.
Vegetational diversity is a hallmark of the Costa Rican landscape.
In fact, the impact of it is so great as to be almost dazzling to the first time visitor. On the large scale, this means that one feels that practically wherever you are,you could go twenty miles in another direction, and you would be in a different life zone with its own set of plant species and correspondingly unique aspect to the features of its overall vegetational appearance. All the reasons for this great diversity occurring within one small country, in area about the size of West Virginia, have been and continue to be an exciting challenge for scientists to figure out. Costa Rica's internal topographic complexities but one aspect to the explanation. Another aspect, which affects climate as well as geological history, is the geographic situation of the country in a position where both Central and South America influences are strong.