Establishment of Nothofagus solandri var. cliffortioides by seeding in Leptospermum scoparium shrublands

Large areas of mountain beech (Nothofagus solandri var. cliffortioides) forest in the South Island of New Zealand have been destroyed by fire and replaced by grassland or shrubland. Mountain beech regenerates into grassland or shrubland mainly by slow spread from forest margins, though instances of long-distance spread into manuka (Leptospermum scoparium) shrubland have been recorded. To determine if manuka shrubland may be used to facilitate establishment, seed of mountain beech was sown under moderately dense and dense manuka canopies, at manuka stand edges, and in open grassland or moss-dominated vegetation at three sites in the Waimakiriri catchment, Canterbury. Seedling establishment after 2 years was strongly influenced by both site and position in relation to the manuka canopy. Rainfall during November of the first year (after seeding in April) was low and 0.3% emergence occurred at a site with stony soils on a steep west-facing slope. Mean emergence at the other two sites was greater (10.6% and 11.5%) and at those sites was greatest at manuka-canopy-edge positions (25–30% of seed sown). Few seedlings emerged in open grassland or moss vegetation and these mostly died. Survival of emerged seedlings after 2 years was high (45–100%) under manuka and at the stand edge. Greater establishment of beech seedlings at the edge of or under manuka stands is attributed to the provision of shade and possibly mycorrhizal inoculum by manuka. Further monitoring is required to determine ultimate seedling survival.