Research Report No. 393

Regeneration of slash burnt coupes in high elevation species forests of East Gippsland.  G. M. Dooley, G. J. McCarthy and P. C. Perry.  March 2005.  19pp. (unpubl.)

SUMMARY

The complex nature of regeneration following harvesting in High Elevation Mixed Species (HEMS) forests has resulted in a number of research studies. This study is a part of that research.

The aims of this study were to:

  • determine the effect of slash burning intensity on eucalypt regeneration over a number of HEMS coupes including carryover coupes.
  • determine the effect of mechanical soil disturbance and slash accumulation on regeneration success.
  • determine the adequacy of draft prescriptions for slash burning to achieve regeneration success.

Thirteen harvesting coupes (7 in 1998/99 and 6 in 1999/2000) were selected across the range of HEMS forest in East Gippsland. Two coupes in 1999/2000 were carryover coupes. All coupes underwent a slash burn for site preparation. At each coupe, plots were set up in which slash burning intensity classes, mechanical soil disturbance and slash cover were initially recorded. Eucalypt regeneration and height, and non- eucalypt vegetation cover and height were then recorded up to 24 months after slash burning.

It was found that:

  • Topsoil disturbance without burning resulted in more eucalypt regeneration than on burnt areas. There was a trend for burnt areas that had mechanical topsoil disturbance to result in more eucalypt regeneration than on burnt areas without any topsoil disturbance, however this trend was not statistically significant.
  • Hot slash burns produce a number of positive factors including the removal of live vegetation, litter, an organic layer, light slash, and soil-stored seed of competitive species. Hot burns also promote early growth in eucalypt seedlings.
  • The presence of light slash results in fewer eucalypt seedlings due to slash being a physical barrier to eucalypt germination.
  • The recommended prescriptions (weather and fuel moisture) to achieve a good burn result do not necessarily result in good regeneration success, due to post-burn factors such as timing of sowing, competition from other vegetation and browsing.
  • There was no evidence from this study that carryover coupes produce significantly different regeneration results compared with burnt non-carryover coupes.