Secondary vegetation succession on the Port Hills Banks Peninsula, Canterbury, New Zealand

Abstract

The structure and canopy composition of successional scrub dominated by broom (Cytisus scoparius), elder (Sambucus nigra), gorse (Ulex europaeus), and mahoe (Melicytus ramiflorus) was measured using a variation of the point-height-intercept method. Stem diameters and age classes of broom and elder populations were recorded. Eight stands in Hoon Hay valley were arranged in order of increasing age which corresponded to a toposequence from dry sites on upper north facing slopes to moist sites on lower south facing slopes. The latest expansion of elder began about 12 years ago when it colonised young broom stands. Broom dies by about 15 years leaving elder, which in turn is invaded by mahoe. Broom and elder are considered desirable species where the aim of vegetation management is to re-establish native forest in this region.

Keywords:

• Cytisus scoparius
• Ulex europaeus
• Sambucus nigra
• shrub populations
• scrub
• secondary succession
• invasion
• Port Hills, Canterbury
• New Zealand flora