Gahnia Grove's Progress report for July 2018
EDIT: Lepidosperma laterale was a slip - I meant Square sedge, L. australe
July: 14.5 hrs liaison and research; 30 hrs monitoring and documentation; 38.5 hrs of weed control; 4.5 hours pathmaking: Total: 87.5
YTD: 25.5 hrs liaison and research; 41.5 hrs monitoring and documentation; 57 hrs of weed control; 4.5 hours pathmaking: Total : 128.5
See recent "News" post for definition of the areas referred to in Observations and Reports for Gahnia Grove. See News for a first Overview of "Cape Honey Flower Bank"
Manuka canopy:
Recent survey of the Clearing side of the Manuka canopy downhill towards the older forest reveals a habitat similar to that already observed below the Annexe and Apron, but with larger light breaks, more pampas, and a few additional native species including Square sedge (Lepidosperma australe), sapling totara and a ?native/?invasive Cordyline rubra. What are we to do about this - remove it (if possible - it's emerging from under a log) or leave it?.
There is an increased density of Watsonia and Pampas in the light breaks that suggests possible impending failure of succession. (see "News") Please send any comments or experience you have to help us interpret the ecology and prognosis of this broken manuka canopy with little understorey and massive bulb invasion.
We learn from an old Kaipatiki Project publication that some part of Eskdale Reserve once held a Bulb farm. Perhaps several truckloads of Watsonia bulbs were left here... or has the bulb reproduced to this density in the lifetime of the manuka?...or was it already dense when the manuka arose?...and without intervention, could the Watsonia result in the return of this potential future forest to kikuyu?
Without intervention, the Japanese honeysuckle would have done that, from the outside in. Its runners had reached light breaks in the canopy which would have enabled it to climb to the canopy in a single season.
We are dealing with the honeysuckle, but have not yet decided what priority and methods to apply to Watsonia control. Currently we are reducing stems (by various means) throughout Gahnia Grove, and bagging any loose bulbs found.
Path: see News
July Report: for Kikuyu control: (see News for general considerations)
Outer edge - The edge of the mown kikuyu area on the Outer, ie road side of the harakeke and island plantings is now being controlled manually as part of the Trial, in addition to the Inner edges of the planting and the Arena.
There has been a little growth in the Outer strip but not enough to pull back yet. The dead sprayed kikuyu has been cleared away from the planting while checking for regrowing rhizomes, a few found and removed.
The dead grass has been used to form a very small barrier to new kikuyu spread, of which there has been just a few short leaves on semi-buried stolons or perhaps emerging rhizomes? Since pullback can only be done on unrooted stolons, we will have to wait and watch to see in what manner the regrowth from the retained mown area develops, and whether pullback can be done and rhizome-rotting brought about before rhizomes penetrate the planted area. This is a particular challenge with harakeke, which provides no shade and whose tubers are no obstacle to the spread of kikuyu..
Top of Arena - Kikuyu is slightly reduced in width due to the barrier of pulled-back kikuyu and honeysuckle having been pulled slightly further up the bank. The kikuyu uphill of the path through the Arena is not yet long enough to pull back, so a kikuyu "path" remains. We continue to follow the principle of a defined kikuyu-free area being gradually extended.
The Arena bank - There is no evidence of live kikuyu and there are several square metres of bare clay. However, small areas of live rooted rhizomes remain, mulched heavily with their own live stolons and rotting foliage, with intermingled honeysuckle vines, some still rooted, some cut or uprooted. These mulch piles are heavy, which helps rotting but makes moving the material difficult. Progress seems to be being made however, with a few more rotted kikuyu rhizomes being uplifted every week or so.
Apron - There is still kikuyu rooted in several small areas, mulched with its own attached stems and with semi-rotted kikuyu from other areas in the Apron where all evidence of kikuyu has been removed and mulch is no longer required - until the inevitable creeping buttercup emerges.
If all mulch piles were to be removed from kikuyu now, remaining rhizomes would break off easily near the ground and would appear to have been controlled, but would regrow. It is hypothesized that allowing adequate time, in the moist (anaerobic?) conditions produced by dense piles of rotting material, allows the microbes of decomposition to proliferate sufficiently to rot the rhizomes, perhaps already stressed by being pulled back on themselves.
Seedlings in the clay bared by removal of kikuyu:
In the ground bared by removal of kikuyu and Japanese honeysuckle, ie parts of the Arena and around the base of harakeke between Apron and annexe, seedlings began to emerge about 20 July.
Native - 1 ? Haloragis erecta
Exotic - 1 fumitory, many Prunella vulgaris, wild carrot and catsear, all of which are being retained at this stage as harmless groundcover that can be used as mulch when needed.
Also a vetch sp, and Common daisy. The daisies may need to be controlled fairly early as they lie close to the ground and can be hard to pull out, but at the moment they are preferable to the inevitable creeping buttercup of which some sturdy specimens are already present in most areas. The vetch may or may not need to be removed depending on its competitors.
Lesser trefoil/Medicago sp is emerging in places and being pulied out as much as possible as it can be agressive and is virtually impossible to completely remove completely from among roots or from tussocks.
Summary of observations of the planted trees
Arena:
Hoheria - 1 x c2mH Hoheria has hardened up since removal of honeysuckle, and is now flowering.
Karamu - 5 survivors of honeysuckle canopy, probably the remains of an earlier "1 per sq metre" tree planting of the whole area, ?10+ years old but almost prostrate after restraint by honeysuckle, have multiple basal branches c15cmD.
Three responded immediately to release, with vigorous new growth coontinuing in subsequent weeks.
One, with only a few terminal branchlets having outreached the honeysuckle, has no new leaves but was flowering heavily on one or two branches. Unfortunately, the branches were already semi-broken by the weight of honeysuckle, and one broke completely during a misguided attempt to remove a remaining heavy piece of honeysuckle yesterday.
One shows no new growth, has discoloured deformed leaves and severely damaged or dead multiple basal branches.
Manuka - where foliage has not died from honeysuckle coverage, manuka has flowered throughout July.
Ti kouka - c4mH trunk released from honeysuckle with no signs if ill-health, except on 1 of the 5 new shoots otherwise growing strongly (from base to head)
Apron:
Akeake - 1 x c2mH
Totara - 2 x c4m were noted at the Clearing end, explaining the number of totara seedlings found there (about 6)
Annexe:
Akeake - noted an additional 1 & 4mH
Wild trees
Arena
Ti kouka - 5 new shoots from its newly-released but severely sloping trunk, maybe to avoid the collapse of the trunk from imbalance.
Putaputaweta - 2 x c2mH in canopy edge at bottom of Arena, surviving new exposure to sun and wind and growing strongly. 1 x c2.5mH in canopy edge at left ofArena, between harakeke and mapou.
Kawakawa -1 x1.5mH - now taller, fuller and lush with developing fruit (female, I think); 1 x1mH at bottom of Arena - survived accidental burial for 2-3 days under dropped honeysuckle vines, but on release was found to be actually c2mH, but too weak and spindly to stand. It hasbeen loosely tied (with cut vine) to a bamboo stake.
Weeds
Throughout: Japanese Honeysuckle - All visible vine has now been removed, and remaining rooted sections mulched with uprooted vines and kikuyu, as heavy, dense and wet as possible. See earlier Gahnia Grove News for more about this Japanese Honeysuckle treatment.
Arena
Blackberry- numerous suckers to 2-3mL removed. Numerous plants cut off at base or pulled out.
Some plants were mulched for days or weeks with decaying leafy material, and were found to pull out more easily after that treatment. We now cut main stems only where necessary for safety or access to other plants; in other cases we remove enough suckers and branches to access the main stem, then bend or break the remaining stems until the whole plant is folded in upon itself, flat to the ground and weighed down with any available plant material until the roots have loosened or the stem has rotted.
Montbretia - Dense clumps of bulbs in places. Larger leaves pulled out, with bulbs where loose
Creeping buttercup - spreading from canopy margins, being mulched as found
Unidentified - seedlings in bare clay
Island Planting
Pampas - The large toetoe at the Clearing end of the Planting was observed to be in fact common Pampas, now manually reduced to c1mH. This will be further reduced, and used as path topping and mulch. Dead material is being removed as quickly as the plants' decay permits, preferably before Spring as wasps are inclined to build nests in the dry base of Pampas stands.
Elaeagnus, Cotoneaster and Japanese spindle tree - no regrowth seen except on the smaller Eleagnus which had been only pruned in its first intervention. Leader now partially broken and young branches leaf-stripped, twisted and knotted together.
Moth plant - one more pod found on ground. Seedlings continue to develop and be removed, becoming fewer
Common ivy - another 2mL seedling found and removed, under dead foliage of the pampas at the clearing end of the planting.
Climbing asparagus - 1 or 2 more seedlings found and pulled out
Manuka canopy
Blue corn lily (previously ID'd as Stinking Iris) - all observed has now been pulled or mulched over, on Annexe margin and under canopy nearby
Watsonia, abundant throughout - see above
Kahili ginger – a few more small stands - stems broken down or cut, some leaves stripped and piled to help rot tubers. No regrowth observed yet
Blackberry – several more seedlings and small plants removed entirely or bent/broken down and mulched
Pampas grass - one large and a dozen or so small stands now flattened or removed.
NB Definition of the downhill-boundary of Gahnia Grove, on further survey hopefully this week, may result in the inclusion of more pampas in the Trial site.
Several Elaeagnus and Cotoneaster to c1mH - stems leaf-stripped, twisted and looped. No regrowth yet.
Kanuka/manuka canopy (previously referred to as "Streamside community")
A single Chinese privet, c0cmD/3mH, at the Flame Tree zone edge, with one branch extending from the canopy and almost touching a low branch of Flame Tree.
The privet has had lower branches cut off and higher branches partially broken and stripped. The branch extending from canopy has been left intact for now to minimise habitat loss, and because its seeds are likely to fall in an area currently without native vegetation, and wet enough to allow seedlings to be easily removed. This will be reassessed after a plan is made for containment of the Flame Trees .
Brush wattle seedlings 10cm - 1mH, several more scattered, removed as encountered
Arum lily - 2nd intervention, squashed down more.
Phoenix palm -2nd intervention, stems bent and looped
Flame tree - Long branch hanging over lower Arena, dropping leaves. Fallen wood found and disposed towards the fallen Flame tree wood on lower Cape honey Flower Bank
Agapanthus - a dozen small plants, all being reduced and mulched, with outer leaf-bunches of plants becoming looser until they can be uprooted, which has started to occur.
Ginger - several small stands.
Intervention 1: All stands either had stems cut and mulched tubers with rotting leaves,
or stems broken down and trampled over the tubers. To be monitored.
Comments
Add a Comment