Gahnia Grove - Site summary and discussion's Journal

Journal archives for June 2018

June 25, 2018

One month of monitored restoration methodology trial...

Progress report for Gahnia Grove 26 June 2018

Period covered: 26 May – 26 June 2018

16.5 hrs of site work,
10.5 hrs monitoring (Observations uploaded to iNaturalist.nz)
11 hrs liaison and research (onsite and email,) with Auckland Council community ranger and contractors, and Kaipatiki Project (site management and loan of tools/clothing)

Gahnia Grove contains areas described as:

Kikuyu margin (along the previous kikuyu footpath, now being converted to native vegetation)
Island planting (c10m x 2m-5m, adjacent the kikuyu walkway along Glenfield Rd and down into the Top Clearing of Eskdale Reserve)
Apron - Several sq/m of kikuyu and other weeds sloping down from the island planting to the arena and manuka canopy
Arena - a larger area of kikuyu, honeysuckle and blackberry, sloping down from the kikuyu path to manuka canopy
Manuka canopy - forms an arc around the arena, and to its left, extending to the Top Clearing of Eskdale Reserve. Manuka to 4-5mH with few other tree or shrub species
Streamside community - no stream seen yet, but wetter ground with more tree/shrub species and more understorey, eg Carex spp. An extension of this community is visible from under manuka canopy at right, further to right and downhill - still to be surveyed.

Notes on Japanese Honeysuckle (Lonicera japonica):
Most of the trees in the arena and kikuyu margin were entirely bound in honeysuckle, with curtains of it occluding light to c4mH , just below the head of the largest ti kouka. Honeysuckle runs under and through all trees, shrubs and grasses throughout the Grove, leafless runners extend in all directions, mostly laterally and downhill, often hidden until they reach a tree, or into the forest floor, where they extend up to 7m before rooting and continuing on their way to the next light-source and another tree to climb.
Runners not yet rooted are easily drawn out, but difficult to see in the gloom under the dense manuka canopy. Runners already rooted at both ends have to be cut and the roots located and removed at both ends.

Kikuyu margin
Kikuyu is little changed in what was previously a mown path dividing an island planting from the mainly-manuka forest margins. During this work and recent rain it has become muddy below the apron, and woody material is being added as a non-slip surface and to reduce compacting.
Suitable materials at present are dead manuka branches, where they are presently covering native foliage or are in excess of requirement for shade/weed control under the canopy. When shrub/tree weeds are sufficiently dried they can also be used. Eg Branches from the felled brush wattle will serve this purpose in due course, if they have not been removed from the site.
Kikuyu has been pulled up the bank from "arena", and has not yet shown regrowth from where it is piled in the form of a border to the arena. This border has had cut and pulled honeysuckle vines added to it, the loose bundles of vine easily moved as needed.

Released from honeysuckle and kikuyu along this margin are:
Manuka - the small amount of surviving foliage on the c2.5mH newly-released manuka is flowering!
Akeake - 1 x c2mH
Hoheria 1 x c2mH, released and leaves hardening on exposure to sun
Kawakawa - 1 x1.5mH, 1 x1mH - both released and foliage filling out
Karamu - 1 x 1.5m, on kikuyu margin: partly horizontal and dead after being bound by honeysuckle, partly surviving with foliage visible
Karamu 1 x 1mH - at base of large ti kouka - almost entirely horizontal and dead, still honeysuckle-bound, but some branches released and showing a little foliage

A clump of Elaeagnus, Cotoneaster and Japanese spindle tree c 2mH had replaced a planted, now dead, tree - treatment by branches incl leaders pruned or partially broken and bent down, and/or t cut near base. Eleagnus Regrowth of those tree weeds not able to be uprooted is to be monitored and dealt to as needed. This area now released for native growth.

Arena
A lot of honeysuckle vine removed already, releasing several trees to 2mH, with several more partially released. Honeysuckle stems removed are up to 4cm diam.
Smaller roots are removed with the vine. Some small to medium size roots have been pulled fairly easily a couple of weeks after removing most of their above-ground material.
There are still a lot of big roots to pull up, throughout the "arena" and along the edge of the manuka forest from the Clearing to the Flame Tree zone, ie throughout Gahnia Grove.

Still to be addressed:
Blackberry - numerous plants
Lots more honeysuckle, releasing live trees first, then removing all runners from forest floor, then margins

Island planting and Apron
The island planting and the "apron" behind it and above the grass path contain Harakeke, manuka, mapou, karamu et al, probably both planted and emergent, and have had the following weeds removed, or controlled for ongoing monitoring and gradual removal:

Tree privet, Chinese privet, Elaeagnus, Cotoneaster: either the branches incl leader partially broken and bent down, or tree/shrub cut near base
Moth plant - pods collected and removed by a STAMP volunteer ; a dozen or so vines cut and pulled out; hundreds of seedlings pulled out
Common ivy - several seedlings to 2m on ground under native planting, pulled out
Climbing asparagus - 1 seedling, pulled out
Kahili ginger - small clumps, pulled out or stems cut and piled to mark tubers,
Japanese honeysuckle running through the kikuyu has almost all been removed, but there will no doubt be remnants that emerge as the kikuyu is eradicated from this area.
Brush wattle- a single sapling c4.5mH has been cut down but not chemically treated, to be monitored for regrowth.
Arum lily - 1 or 2 small, pulled out or pushed over/down

In the unmown and untrimmed "apron", sloping down from the island planting to the grass path, Kikuyu has been lifted and dropped backwards to suppress itself and other weeds eg paspallum, while removing infrequent honeysuckle runners and pulling out their roots.

Bare earth is beginning to appear between clumps of disturbed kikuyu in the Apron and just below the kikuyu path. These areas will be watched for seedlings, and may later need mulching in places with available decomposing weeds to suppress new invasions and prevent drying out.

Discovered in planted margin and apron:
Totara- 1 x 1.5mH
3 x Totara Seedlings to 8cmHo
et al

Manuka canopy
Japanese honeysuckle runners, lwith arge roots and climbing stems on margins
Stinking iris. abundant on margin and under canopy nearby
Watsonia , abundant throughout
Kahili ginger – several small clumps
Blackberry – several seedlings and small plants, some removed entirely, some reduced and suppressed by trampling and/or smothering
Exotic (Phoenix?) palm - 1
Pampas grass - about 6 small stands reduced and suppressed by trampling and/or smothering. A big one remains to be addressed.
Eleagnus - 1x c1mH
Cotoneaster- 1x c1mH
Brush wattle seedlings 4-30cm, removed as encountered

Found:
2 x Mingimingi (Leucopogon cyathoides) under manuka canopy, fruiting abundantly
Gahnia xanthocarpa, with fruit, several large plants under manuka canopy
more Gahnia sp. further back in forest
1 x Rush - for ID
1 x Pigeonwood (Hedycarea arborea) c1mH
seedlings:
numerous scattered Karamu, first pr leaves only
1x Kohekohe

Streamside community
This wetter habitat has more native species, and no doubt weeds, still to be surveyed

Discovered :
1 x Putaputaweta c2m, just behind the honeysuckle "curtain". Will need to ensure moisture retention around this after removal of the honeysuckle shading it.
Carex - ?dissita/lambertiana, several, edge of canopy, downhill towards wetter area

To be addressed:
Agapanthus to "right", ie nearer flame tree, where ground slopes down steeply and vegetation is denser.
More honeysuckle, runners as for Manuka canopy, plus dense occlusive cover hanging from ti kouka on margin

There is a steep slope from this point to the right, which will need to be assessed further as weeding continues. Due the steepness and uncertain stability of this slope, a contractor is need to assist with weed removal from here to the Flame Tree Zone.

One sack of inorganic refuse/litter has been collected and placed on the uphill boundary for removal by Council at their convenience.

Needed: 2 pr loppers, light and heavy (and return KP's borrowed pair)
Secateurs, 2 pr heavy and light (and return KP's borrowed pair)
Pruning saw - extensible handle would be useful
Wet weather pants and jacket (but in the meantime thanks to KP for the 3XL Tornado pants! The product is fantastic, and they are invaluable at present)
Workboots (gumboots are ok up to a point,but not always stable on slopes)
A v. small pop-up tent would be useful for shade/shelter

Posted on June 25, 2018 11:36 PM by kaipatiki_naturewatch kaipatiki_naturewatch | 1 comment | Leave a comment