Influence of industrial forest residue applications on Pinus taeda: soil, litter, growth, nutrition, and wood quality characteristics

Nutrient return to soil by applying forest industry residues help ameliorate soil nutrient exhaustion and promote forest management sustainability. This study evaluated the effects of forest industry residue application on soil attributes, on forest floor amounts, and on growth and nutrition of Pinus taeda L. (loblolly pine). Six rates (0, 14, 25, 49, and 60 T ha(-1)) of residue (boiler ash and cellulose sludge mixture) were applied to P. taeda stands on a low fertility soil. Seven years after application, trees were harvested for wood volume, wood biomass, canopy mass, and nutrient composition. Wood density was determined along the trunk length. Soil samples from 0-10 to 10-20 cm depths were collected for evaluating chemical attributes. Although residue application only resulted in small increases in soil Ca and P availability, high yield enhancements were observed with no compromise to wood density. Maximum growth response was obtained with the 49 T ha(-1) residue application. This rate enhanced trunk volume from 117 to 250 m(3) ha(-1), total biomass from 76 to 127 T ha(-1), and total C from 34.5 to 57.2 T ha(-1). Residue application decreased Mn content in all biomass compartments, and values above 193.5 (needles) and 26.2 mg kg(-1) (bark) defined low annual growth increases. Residue application also decreased Al, Fe, S, B, Ca, and P concentrations in branches or needles. Forest floor was enhanced by residue amendment, which increased C sequestration by 7 T/ha. Forest sustainability practices can be enhanced by applications of industrial residues while improving tree yield and nutrition.

Automated summary

The application of forest industry residues can improve soil nutrient exhaustion and promote sustainable forest management. This study evaluated the effects of residue application on soil attributes, forest floor amounts, and the growth and nutrition of Pinus taeda. The results showed that the appropriate application of residues can enhance tree growth and biomass without compromising wood density.