Early growth responses from weed control and planting larger stock of Pinus radiata are greater than that obtained from mechanical soil cultivation |
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| Authors: | South David B. Zwolinski Janusz B. Kotze Heyns |
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| Affiliation: | (1) School of Forestry and Wildlife Sciences and Alabama Agricultural Experiment Station, Auburn University, Auburn, AL 36849-5418, USA;(2) School of Agricultural Sciences and Agribusiness, University of Natal, Scottsville, 3209, RSA;(3) SAFCOL Research, Sabie, 1260, RSA |
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| Abstract: | Early growth of two grades ofbare-root Pinus radiata D.Don seedlingswere studied in response to four soilcultivation treatments and two weed controltreatments.Soil cultivation treatments included (i) pitsmade by hand, (ii) pits made with an auger,(iii) ripping alone, and (iv) ripping plusdisking. Weed treatments included (i) manualrelease 1 year after planting or (ii) totalweed control for 1 year involving the use ofherbicides and additional hoeing. Bare-rootseedlings were separated into either medium(4.1-mm average root-collar diameter; height25–31 cm) or small (2.8-mm average root-collardiameter; height 14–20 cm) size classes.Growth on this site was excellent and 7 yearsafter treatment, trees in the least expensivetreatment averaged 12.8 m in height. Use ofmedium seedlings and extra weed controlincreased merchantable volume by20 m3 haminus 1 and 19 m3 haminus 1,respectively. When combined, the increase was39 m3 haminus 1. However, none of the soilcultivation treatments caused a significantincrease in merchantable volume. Disking onthis site proved to be of no benefit. Aboundary-line analysis was used to examine themarginal returns from investing in intensivesilviculture. |
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| Keywords: | cultivation growth response intensive silviculture stock size weed control |
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