SHORT-TERM RESPONSES OF TREE GROWTH RINGS IN NATURAL GAPS FOR FOREST MANAGEMENT

Objective: Effects of treefall gaps on tree radial growth pattern and vessel size plastisity were evaluated in cross sections of stems of moist tropical upland forest trees at Amazonas state, Brazil. Growth rings and vessel area of trees growing on 15 natural gaps in primary forest aged ≥ 4 years were studied macroscopically. Method: For determine growth periodicity, anatomy feature and study growth patterns of difference natural species, incisions made in the vascular cambium (Mariaux windows) was applicated. Analyses were performed on data of the community as a whole, and divided according to successional stage and vertical stratum to understand tree growth response. Results: Growth rings of 175 among 226 species sampled (77 %) were visible with and without the use of a 10 x lens. The vast majority (127 species, 73 %) formed rings by fiber dimensions (lumen area), whereas 18 species (10 %) formed rings by vessel size and frequency. After gap formation, mean ring width of 384 individuals of 115 species increased from 1.77 ± 0,04 to 2.46 ± 0.06 mm year-1 (P < 0.001), and mean vessel area of 399 individuals of 148 species increased from 0.062 ± 0.002 to 0.071 ± 0.004 mm2 mm-2 year-1 (P < 0.001). Variation in growth ring and vessel area was more evident in small individuals in larger gaps. Conclusion: The applicated method for visualize difference of change in anatomy feature of each specie and group of successional, of canopy position, was viable, comparing befor and after gap formations time.