Recommendations for the establishment of trap tree plots for the monitoring of Sirex noctilio under South African pulpwood and sawtimber plantation conditions

Croft PK, Verleur PM
Publication Type
Technical Note
Publication Year
TN 10-2017

South African pine growing areas, the plantations are managed under various silviculture treatments to produce numerous products. The diversity in stocking, rotation age, species, thinning regimes etc. creates a mosaic pattern. Within this mosaic pattern there is a need to establish trap trees to monitor the presence of Sirex noctilio.

Trap trees are created by applying herbicide to 13 to 20-year-old trees, six weeks before the S.noctilio peak emergence period. Older trees will die slower and younger trees will die quicker, which complicates the management of trap trees as some trees will be too wet and others too dry during the optimum time for inoculation of Deladenus siricidicola. Therefore, it has become necessary to standardize the establishment of trap trees in compartments of uniform age, species, risk rating and thinning status, to achieve effective results.