Seed supply and forest recovery after the Carey State forest wildfire.  M. T. Lutze and D. Terrell.  April 2000.  25pp. (unpubl.)

SUMMARY

Regeneration studies were carried out in alpine ash dominated stands in Carey State forest over the period 2 to 15 months after varying levels of severity of wildfire, which had swept through large tracts of alpine and sub-alpine vegetation in January 1998. Investigations included seed supply estimates, from in-crown and fallen capsules, and germination in soil samples, vegetative regeneration assessment and seedbed surveys conducted within 3 months of the fire. Germination and survival monitoring before and after harvesting during spring 1998-autumn 1999, were carried out in selected stands.

It was found that:

• Vegetative recovery of all species except alpine ash was adequate to ensure stocking of those species.
• Seed stored in the crowns of alpine ash increased with the age of the trees and should have been adequate for regeneration of stands of 1979 and earlier origin. The results of germination tests on soil samples indicated that there was greater destruction of seed in the burnt crowns than in the scorched crowns. However a substantial proportion of the estimated seed supply survived the fire.
• Early 1980s regrowth with overwood of 1939 and older origin had adequate seed in the canopy for regeneration, but stands of 1980s and later origin without overwood required artificial sowing for regeneration of alpine ash (up to 139 ha).
• Seedbed conditions deteriorated during autumn 1998 on grassy sites and some scalping followed by artificial sowing has been necessary. However over most of the burnt area, which had a shrubby understorey before the fire, seedbed conditions were generally acceptable for spring 1998 regeneration.

Observations indicated that profuse germination of alpine ash occurred in the first spring after the fire over all strata, including areas salvage harvested in autumn 1998. Growth to the following autumn was good on most sites and seedlings were advanced well enough to survive their first winter. However grass competition has been intense on some sites.

On the basis of limited monitoring of harvested areas, harvesting in spring 1998 to autumn 1999 increased mortality over natural levels and reduced regeneration to marginal levels (50-65% of 4 milacre plots stocked). However, generally there was sufficient receptive seedbed created through harvesting to warrant sowing of disturbed areas to increase regeneration success.

Recommendations are made for monitoring of regeneration and treatment of understocked areas.