Canopy recovery four years after logging: a management study in a southern brazilian secondary forest secondary forest

ABSTRACT

Background:

Understanding forest dynamics after logging is essential to define forest management cycles and intensities. In secondary forest, especially in the Atlantic Forest Domain, these studies are still scarce. Monitoring of the canopy structure after tree harvesting can be performed by hemispherical photographs, where canopy opening is commonly analyzed. This study evaluated changes in canopy opening four years after tree harvesting in a secondary Atlantic Rainforest in southern Brazil. We used hemispherical photographs to determine the Canopy Openness (CO), Leaf Area Index (LAI), and Diffuse Fraction of Photosynthetically Active Absorbed Radiation (FAPAR_dif) in eleven permanent plots.

Results:

We found that harvesting resulted in a momentary increase in canopy opening and light availability in the understory. Four years after harvesting, CO, LAI and FAPAR_dif recovered or even exceeded the original values of the forest. We observed a significant correlation between CO and number of trees harvested with DBH > 30 cm. Weak correlations were found between these canopy related variables and the logging intensity.

Conclusion:

In conclusion, we recognized that changes of CO, LAI and FAPAR_dif after timber harvesting presented short duration. This indicates that the applied logging intensities, 21.8 to 51.1% of the total basal area, did not exceed the resilience of the forest canopy and it’s recovering four years later. However, additional studies should be carried out to observe vegetation dynamics, such as species composition, vertical structure, productivity and community stability, in order to improve management schemes of secondary stands in the Atlantic Forest.

Keywords:
Atlantic Forest; canopy openness; leaf area index; diffuse fraction of photosynthetically active absorbed radiation; sustainable forest management