Midrotation management including vegetation control and fertilization can improve growth and yield of southern pine stands. This study investigated the 12-year response of slash pine (Pinus elliottii), thinned at midrotation to additional treatments of herbicide, fertilization, liming (one site), and combinations of these treatments in the Coastal Plain region of Georgia, USA. There was a significant treatment x stand age interaction observed at the Ware County site for height (p<0.001), dbh (p<0.001) and individual tree green weight (p<0.001). The herbicide + NPK and herbicide treatments resulted in the most consistent growth improvements 0 to 4 years post-treatment compared to the untreated control. The lime + NPK and herbicide treatment resulted in the longest lived (4 to 12 years) significantly improved growth response. Results revealed no tested treatments improved growth during the 12-year study duration at the Wayne County site. Results from this study suggest that thinned slash pine stands with diagnostics indicating midrotation fertilization or vegetation control may be beneficial do not always respond as expected to inputs. When stands are responsive, single application midrotation treatments can offer long-term growth improvements, yet growth response can differ depending on time since application.
Read full abstract