Report for October 2018
Liaison: 4 hrs; Monitoring: 4 hrs Weed-control: 14 hrs
YTD: 38.5 hrs liaison and research; 57.5 hrs monitoring and documentation; 93 hrs of weed control; Total : 189hrs
Contractor assistance : 8 hours
Kikuyu continues to grow in the previously mown “path” through Gahnia Grove, lightly mulched on the outer edge (nearest the road) with loose drying honeysuckle vine, and on the inner edge, along the bared clay and canopy marginn, with rotting kikuyu, pulled herb weeds and a few plastic, cable-tied bags holding rotting montbretia and Watsonia bulbs (Arena and Apron), and with dead pampas in the Annexe.
In the Arena, remaining Blackberry and honeysuckle roots have been sprouting fast, ignoring the remaining loose dry mulch of dead vines. They were uncovered throughout, and those too big and deep to be uprooted by hand will be grubbed out, as the ground is now too dry for them to rot under mulch.
“False bindweed” (Calystegia sp.) continues to erupt throughout the cleared Arena and canopy margins, scrambling through mulch and climbing trees. It is being broken off with as much underground runner as possible, and hung in trees, laid on dry mulch in the sun, or collected in a mesh bag to dry. It would be useful to know of any experiences regarding the reduction of the underground mass to reduce future invasion. Does pulling it more frequently help starve it? Is there a limit to how long it survives underground without foliage? Is there a maximum height it can climb – ie will dense canopy kill it off?
Weeds found and removed during the month once again include seedlings of climbing asparagus, Kahili ginger, cotoneaster, brush wattle, a few more previously hidden runners of honeysuckle under the manuka/kanuka, and another previously missed stem of Common ivy emerging from leaf litter under the planted trees in the Annexe. Ivy appears to hide very effectively for a long time.
About a dozen Agapanthus to .4mH were reduced earlier by removal of leaves and piling the leaves and additional debris on top of the plants. The tuberous bases weakened and were able to be wrenched out of the clump successively. Most of the bases have now been removed by this method, but many seedlings have now germinated around them. These are being broken off or grubbed out with a little hand-held “daisy grubber”, this tool proving useful with honeysuckle and blackberry roots too.
The tree privets had their new shoots plucked off again – this time a 5-minute operation covering all three trees, with branches bent down further again to allow the now-growing adjacent native trees more space.
The 3mH cotoneaster found under the manuka/kanuka canopy was ring-barked, at about a metre height because the base of the tree is inaccessible in dense Gahnia foliage. Some suckers emerging from the Gahnia were leaf-stripped once again and broken down further.
There has been ongoing pulling of Montbretia in the Arena, the bulbs being gathered into heavy-duty plastic bags and twist-tied, to rot over a period yet to be determined. Rotting in barrels has been used by others, but the period required is unknown.
The specimen of the indigenous "Esler's Weed", or Senecio Eslerii, found in the Domain Rd margin of the forest has been revisited. It has grown but the seed has not yet developed. https://inaturalist.nz/observations/17956518
This specimen is sheltered by a Puriri and Harakeke now being enveloped by Japanese honeysuckle, Periwinkle and Calystegia, so the Esler’s weed may not survive, but other seedlings have been found nearby, among the kikuyu around planted tuhara:
https://inaturalist.nz/observations/17930430
https://inaturalist.nz/observations/17956499
A bit of kikuyu was hand-weeded from these Esler’s Weed seedlings to protect them and reduce the need for line-trimming, but in case these are lost, a few seedlings have been transplanted to Gahnia Grove and one to a private residence for ongoing cultivation and seed-sourcing.
Cape Honey Flower Bank
The Contractor currently assisting the Project has cut down all the Cape Honey Flower on Cape Honey Flower Bank (which will retain its name for historical reasons ☺ and convenience).
The CHF stems/trunks proved to be up to about 4m long and mostly horizontal. It is not yet known how fast the rooted bases will regrow, if at all.
The honeysuckle and blackberry intertwined among the CHF have been uprooted where possible. Remaining roots will be grubbed in a few weeks when shoots reveal their presence.
The wood has been piled to leave as much ground as possible clear for removal of the many remaining honeysuckle roots, when located as they shoot.
This wood is light enough to be moved easily for use as mulch once it is dry enough to break into shorter lengths. The foliage is not of significant mass, and wilts quickly.
Several mature ti kouka, karamu, mapou and a huge harakeke have been released and are poised to canopy CHF Bank. They are in much better shape than the trees released in the adjacent Arena, where the honeysuckle invasion was much more advanced.
Tradescantia at the bottom of CHF bank is being uplifted and piled in rows across the bank. This provides continued moisture-retention and protection from shrub/tree and grass weed invasion, while the tradescatia rots entirely to humus over a couple of years,with eventual removal of a handful of stems. This can take up to 5 years with tthe ongoing addition of newly-gathered tradescantia to piles, which are gradually themselves accumulated into fewer piles. Monitoring is quarterly initially,reducing to annual over 2 years. If there is found to be water flow over the area in winter, the piles, reduced after summer rotting, will be relocated to a drier area, eg higher up the bank and nearer the Flame tree, where there is already tradescantia.
There is dense deep tradescantia in the downhill-extension of CHF bank, under canopy of kanuka, mahoe, karamu and Flame Tree. Gradual removal of tradescantia from the forest can be done without soil dessication and increased weed invasion. Piling it on the sun-exposed (and already tradescantia-infested) CHF bank will provide soil moisture and humus there for native plant development.
As expected, a few karamu seedlings have been found already in the small area released from tradescantia at the canopy margin on CHF Bank. A few green karamu fruit were also observed.
Interesting find: A 1 litre soft drink bottle long-discarded in the forest, its bottom broken out and holding about a teaspoon of dried sediment in which a small Petako (Sickle spleenwort) was growing, only slightly constrained by its "tunnel house" situation.
https://inaturalist.nz/observations/17271430
Many thanks to Ventia for the educational signage posted at the boundary of Gahnia Grove with the Clearing.
