Trip Report – 3 September 2011:   Skull Gully, Wainuiomata Water Catchment

Map: Topo50-BQ32 Lower Hutt.

This significant area of mostly unmilled forest includes numerous emergent kahikatea, rimu, miro and northern rata.   The trunks of some these trees, aged 500-800 years, are up to 1.0 - 1.5 m diameter.   It is sad, that even today, large trees like these can be milled legally in some parts of the country, destroying a flora and fauna habitat that may contain undiscovered species.

In the canopy of these giants we saw large clumps of Collospermum hastatum, C. microspermum, Astelia solandri, orchids e.g. Earina autumnalis, E. mucronata and Winika cunninghamii; the fern Asplenium polyodon, Pittosporum cornifolium and Griselinia lucida.   The canopy below these emergent trees included tawa, hinau, pukatea, black maire, white maire and kamahi.

We botanised close to the track, which crosses Skull Gully Stream frequently, leading to a swamp 1.4km from its forks with the Wainuiomata River.

At the start of the track we botanised a short distance under tall kanuka, that established after logging ceased sixty years ago, when the land was purchased for water collection purposes.

On a shady, undercut clay stream bank, at the first stream crossing, we saw Trichomanes elongatum, a fern uncommon to Wellington.   Other plants of interest along the track / stream were a matai* seedling, Raukaua edgerleyi*, Clematis forsteri, Trichomanes endlicherianum*, Carex dissita, C. forsteri, C. secta, Polystichum vestitum and hybrids with P. silvaticum, and Uncinia distans.

The swamp which covers an extensive area contains no open water, other than small stream pools.   It has a partial canopy cover consisting of manuka, Coprosma tenuicaulis, with regenerating kahikatea towards the western margin, and Austroderia fulvida prominent on its eastern margin.   Some plants of interest in the swamp and its margins with the forest were; Melicope simplex*, Raukawa anomalus, Clematis foetida, Botrychium biforme, Blechnum penna-marina ssp.alpina, Eleocharis acuta, Machaerina rubiginosa, M. tenax, Schoenus maschalinus, Potamogeton suboblongus, Typha orientalis, Ranunculus amphitrichus and R. macropus*.

We thank Greater Wellington Regional Council for permission to list plants on a field trip in this magnificent forest, and will send the council, DOC and NZ Plant Conservation Network a copy of the list.

(* = only one plant seen)

Participants :   Gavin Dench, Pat Enright, Chris Hopkins (leader / scribe), Chris Horne, Kath Hurr, Pat McLean, Pascale Michel, Barbara Mitcalfe, Mick Parsons, Sunita Singh, Owen Spearpoint, Grant Timlin (GWRC ranger).