We have just had a week blessed with calm, still, partially-overcast days and mild temperatures. I have been out weeding with Craig and Neil as the rest of the vollies and Gareth camped out at Denham Bay to work over on the other side of the island.
On Monday we completed a block up behind the hostel. The slope was approximately 25-30 degrees and we followed the contour lines sweeping east-west. We were mainly looking for passionfruit and Brazilian Buttercup in open, mixed pohutakawa forest.
Tuesday saw us back in the crater on a flat section to the east, bordering Blue Lake. The forest here mainly comprises young 40-45 year old pohutakawas with some patches of high fern. This area was within the blast zone of the eruption in 1964, hence the uniform age of the trees. At the edge of the plot we were blocked by a wall of windfall trees which had come down in the 2006 eruption. We encountered very few weeds in this area as it seems most of the ash had probably covered and killed off the buttercup and guava seeds and seedlings previously there.
It was back into the crater on Thursday but this time to the western side and a place called Dry Crater. The area we had to weed is approximately 4 hectares, so quite compact. It’s like a large amphitheatre with a flat base which was quite easy going once we had dropped down the walls. Brief settlement in this area was attempted between 1889 and 1892 as part of the Kermadec Island Fruit and Produce Association settlement. During this time the government sold blocks of land with the aim of producing fruit and shipping it to markets in Sydney. However, a lack of fresh water, the challenging topography of the land and the hardships encountered by the settlers meant the scheme was doomed to failure. We were looking for signs of grape, figs and purple guava but encountered none of them at all.The Dry Crater
It is a lovely spot and an excellent site for a concert, we decided. (Mechanic Dave buys a Lotto ticket on the interweb each week and has plans to fly in AC/DC to entertain us when he strikes it big. It would work extremely well if the tech support could time an eruption for the climax of the music.)
On Friday we went to a steep, sunny slope on the north side of the island, hunting for madeira. This is a creeping vine that climbs up surrounding vegetation, potentially smothering it. Aside from the aerial plant, it has an extensive system of underground tubers. These are very friable and break off when pulled, so need to be meticulously dug out as this plant only needs to look at the ground to shoot away again. Thankfully Madeira only exists at a small number of sites here on Raoul. It was first noted in 1967 but control is now well underway thanks to a regime of spraying the vines with an Escort/ Pulse mixture (Roundup is ineffective). The vine is very hard to kill with herbicide because of its numerous branching tubers. Sprayed plants will defoliate and the nearest tuber dies but it will re-sprout from the next tuber along, so you have to carefully prise out any surviving bits with a hook-shaped wire. After gathering the plant it is brought back to base and burnt.Weeding for madeira
We were roped for this site as the ground is very loose and the plant grows on the slopes at the top of vertical cliffs with the sea crashing in on the rocks way down below where we work. Between the three of us we got 35 kg of madeira vine and rhizomes this time out – a good haul.