<i>Pseudotsuga menziesii</i>

Mycorrhizal colonisation of Douglas-fir and Corsican pine seedlings in soil from kānuka and mānuka dominated shrublands in Canterbury was studied using a bait plant technique. Soil cores were collected from 10 sites of each shrubland, transferred to a glasshouse, and sown with seed of both tree species. Mycorrhizal colonisation was examined after 19 weeks’ growth. Overall, seedlings of Douglas-fir were larger than those of Corsican pine, but the amount of Corsican pine seedlings that were colonised (56%) was about twice that of Douglas-fir (29%).

The establishment and subsequent impacts of invasive plant species often involve interactions or feedbacks with the below-ground subsystem. We compared the performance of planted tree seedlings and soil communities in three ectomycorrhizal tree species at Craigieburn, Canterbury, New Zealand – two invasive species (Pseudotsuga menziesii, Douglas-fir; Pinus contorta, lodgepole pine) and one native (Nothofagus solandri var. cliffortioides, mountain beech) – in monodominant stands. We studied mechanisms likely to affect growth and survival, i.e.