Piling secondary subtropical forest residue: long-term impacts on soil, trees, and weeds

Authors: ZUCON, ANA ROSARIA - Federal University Of Parana Polytechnic Center; PEDREIRA, GUILHERME - Federal University Of Parana Polytechnic Center; MOTTA, ANTONIO - Federal University Of Parana Polytechnic Center; GOTZ, LENIR - Universidad De Sao Paulo; MAEDA, SHIZUO - Brazilian Agricultural Research Corporation (EMBRAPA); BASSACO, MARCOS - Western Paraná State University; MAGRI, EDERLAN - Federal University Of Parana Polytechnic Center; Prior, Stephen - Steve; SOUZA, LUIZ - Federal University Of Parana Polytechnic Center; DE OLIVEIRA JR, JAIRO - Federal University Of Parana Polytechnic Center

Submitted to: Forests
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2022
Publication Date: 7/26/2022
Citation: Zucon, A.S., Pedreira, G.Q., Motta, A.C., Gotz, L.F., Maeda, S., Bassaco, M.V., Magri, E., Prior, S.A., Souza, L., De Oliveira Jr, J.C. 2022. Piling secondary subtropical forest residue: long-term impacts on soil, trees, and weeds. Forests. 13:1183. https://doi.org/10.3390/f13081183.
DOI: https://doi.org/10.3390/f13081183

Interpretive Summary: Information on the long-term effects of piling secondary forest residue on soil chemical properties, growth and nutrition of loblolly pine and weeds are sparse. Three decades after piling, large variations in tree growth were traced to this previous management practice. A large residual effect of piling was seen in weed growth after 30 years, but this did not seem to limit pine seedling growth. Findings suggest that soil improved in terms of P and K availability after 30 years. The maintenance or increases in soil organic matter in piling areas suggests that this previous practice did not compromise sustainability of this forest system. This information can be of great importance to foresters seeking to understand management practices that increase soil nutrition, reduce negative environmental effects, and guarantee forest productivity and sustainability.

Technical Abstract: The objective of this study was to evaluate the long-term effects of piling secondary forest residue (after 3 decades) on soil chemical properties, growth and nutrition of Pinus taeda and weeds at three locations. After secondary forest removal and residue piling, areas were cultivated with P. taeda (22 years), followed by eucalyptus (7 years), and returned to P. taeda. At 2 years of age, tree height and needle nutrient levels of ongoing P. taeda from areas influenced by residue piling and areas outside the piling zone were evaluated. Biomass and nutrient levels of herbaceous and shrub weeds, NDVI indices (via a drone), and soil chemistry were also evaluated. Residue piled areas displayed a decrease in soil pH and an increase in available soil P and K. Although herbaceous and shrub weed biomass increased 2.5 to 10 times in residue piling areas, this did not compromise pine growth. While residue piling had little impact on the nutritional status of pine and weeds, NDVI values indicated greater plant growth in piling areas. In general, the long-term effect of residue piling was an important factor associated with the large variation in tree growth and weed incidence after 3 decades.