Trees of Saccoglotis guianensis Benth and Andira parviflora Ducke with approximately 26 meters high were sectioned in seven parts to study dimensions of fibers and vessels elements. In radial direction both species showed an increase in fiber length with some irregularities from pith to cambium. The shortest fibers were found in the top of the stem and where there's the maximum number of vessels per square millimeter. It's discussed the influence of growth regulators on the vessels elements. There is decrease in fiber length and vessels elements from base to top after it has reached a high value in determined height and a irregular decrease in width of these elements from base to top of the trees. In radial direction both species showed a small increase in width of the fibers and vessels elements. These elements are shortest in the branches and where the number of vessels per square millimeter is high for both species. The ratio W/C utilized as estimation of the ratio cell wall volume to cell volume decrease from pith to cambium. It's presented 10 graphs and one table and discussed the factors which can have influence on the variation of elements all along the tree.