Trip Report – 11 June 2011:   Upper ‘Solomon Knob’ spur, Wainuiomata catchment

Map: Topo50-BQ32 Lower Hutt.

The weather had cleared from the heavy overnight rain, but more was expected about the middle of the day, so we moved quickly to the start of the spur just through the gate at the old Morton Dam on the Wainuiomata River.   We were privileged to have access to this gem of a forest, thanks to permission from Greater Wellington Regional Council ranger, Grant Timlin.   The lower part of the spur known as ‘Solomon’s Knob’ is one of the first major ecological reconstruction projects attempted in the Wellington region in the early 1990s.   Eco-sourced species were planted on this dry, gorse-infested, north-west facing slope; probably over a silt layer sourced from the base of the now defunct dam nearby.   Pest control was essential for the establishment phase of this revegetation.   A surprise invader, in shrubland, right beside the track, was a Macadamia tetraphylla seedling!

The spur has a trail for servicing stoat traps as part of a network throughout the Wainuiomata catchment.   We moved quickly up the first 1km of this trail to trap 13 as we had thoroughly botanised this on the previous trip in May 2010.   The challenge was to add to the Mitcalfe / Horne list comprising over 145 native species that took us to the top of the spur where the spur intersects the East Whakanui Track.   We reached an area of successional forest that was victim of extensive pig rooting.   It seemed even worse than when seen on the last trip.   It was here in the disturbed area that we added Diplodium alobulum.

The canopy soon became predominantly silver beech and black beech.   We saw the odd emergent northern rata, but near the trail they appeared to be mainly damaged stumps supporting aged kamahi.   Along the trail was extensive Metrosideros fulgens, much of it in flower.   As we progressed up the spur, the trackside Coprosma species graduated from predominantly Coprosma rhamnoides to C. foetidissima and the confusing C. colensoi.

Before lunch, in the last of the dry weather, we had added Hymenophyllum villosum.   The dark clouds above accentuated the damp nature of this spur and it was not surprising then that, among this cloud forest, we found Hymenophyllum pulcherimum and H. flabellatum near the top as an addition to the already extensive list of filmy ferns.   Soon we saw three small plants of Brachyglottis kirkii, two of them suffering from serious browsing damage.   We added Sticherus cunninghamii and mountain five-finger just before turning back after we had reached the East Whakanui Track.

We turned back and soon noticed a lot more S. cunninghamii on the way down.   Puzzled as to why we had not seen it on the way up, it soon became clear that we were on a different trail that was leading down the spur to Nikau Stream, two catchments away from our intended route, with a much steeper descent!   Also above us were hard beech, the first time we had recorded this in the catchment.   Amid the scramble down we noted the slippery clay banks were festooned with mats of Libertia micrantha.   Happily with aid of fortuitous cell-phone reception, we avoided the expected additional half-hour walk back to the vehicles.

Participants :   Gavin Dench, Chris Hopkins, Chris Horne, Barbara Mitcalfe, Sheelagh Leary, Rodney Lewington.   Pat McLean, Mick Parsons (leader / scribe), Darea Sherratt, Sunita Singh, Roy Slack.