Report for January

January:
Liaison: 13.75 hrs; Community liaison (curious Reserve users and Strawberry stand customers) 1.5hrs
Monitoring and documentation: 35 hrs
Weed-control: 55 hrs
January total: 105.25

YTD: 73.75 hrs liaison and research; 1.5hrs community liaison
172 hrs monitoring and documentation
250.5 hrs of weed control
YTD Total : 497.5 hrs

We have already noted that this particular project is time-intensive for reasons of study, experimentation and recreational pleasure. Nonetheless, we record all the hours spent on site since some of the detailed weeding and mulch rearrangement we do in the process of monitoring and exploration may contribute to the outcome, to avoid underestimation of the hours needed for any future such project. We hope that this practitioner or others will in the future trial the methodology with less frequent and detailed physical attention and monitoring, recording a more cost-effective transition to native vegetation over several years through allowing some weeds to grow larger or more numerous before controlling them. With ongoing monitoring and weeding eg quarterly, and knowledge of the behaviour and interactions of both exotic and native species present, it is of course not always necessary or even desirable to remove all instances of a weed on first sighting.

In January, like December, time on site was particularly lavish due to holidays and experimentation with the new mulch border for visual appeal in this very public site, visited every few minutes through the holidays by customers of the Strawberry, Flower and Cherry sales stands on the adjacent roadside.

The number of passersby, frequently stopping to express their interest, curiosity and support, also contributed a little to the time spent. A few phone numbers were offered and accepted from those whose live close by, but in general, after encouraging participation in similar Projects here or elsewhere, we referred people to Council and Kaipatiki Project.

Weed regrowth was not significant in January. However, we visited the site 16 times to:

-monitor and revise kikuyu margin pullback methods affecting the appearance of the mown area

-assess and reduce potential fire-hazard from dry grass and woody material

-arrange mulch for optimal appearance in this very public site

-help erect the cordon

-trial some small home-made interpretive signs.

We took the opportunity on each visit to examine all areas of the site to learn what changes, if any, were occurring. And naturally, as we explored the site, we continued to pluck small occurrences of weeds as encountered.

It seems likely that regeneration would have continued unimpeded by weeds without our interventions of December and January, but as we cannot be sure how much difference it would make if visits were fewer and shorter, we continue to log all the hours spent on site.

Calystegia continues to emerge and start to climb. Though it is occurring mainly among the exotic herbs so is not a threat to native trees or seedlings, we pick it off in passing in hopes of reducing the underground mass and thus, presumably, the vigour of its invasion next Spring.

Brush wattle seedlings have been even more numerous than last month. Removal of these is not urgent, but most were removed anyway in the process of monitoring. Very few wattle seedlings were found in the initial weeding, when two young adults were present on the site, compared to the number of seedlings occurring now. This was expected to occur with the exposure of ground through weed removal.

Moth plant seedlings continue to be abundant on lower CHF Bank along the outer margin of the kanuka/mahoe/Flame Tree canopy, wherever Tradescantia has been removed. Most can be uprooted completely, but some break and are mulched with Tradescantia. This area will need at least quarterly weeding to prevent a renewed infestation of the mature vine. The mature vine uprooted here in spring, however, has not yet been observed shooting.

In the Apron Planting, where several smaller mature and juvenile vines were uprooted or broken off last winter, the broken ones are reshooting among the leaf litter under the densely planted trees. It is necessary to crawl under the trees to control the regrowth, and complete uprooting is still not possible in the hard clay. Seedling germination here is now rare, after dozens being removed immediately on their appearance in spring.

Kikuyu control throughout the interior of Gahnia Grove has proceeded more rapidly than expected, in both previously unmown and previously mown areas. Currently none is visible, and only c. 7.5 sq m of live rhizomes remain for pullback once it re-emerges.

At the edge of the mown area, kikuyu is being successfully controlled at present along c. 60m of the site’s boundaries with 1-2hrs a week of pullback and rearrangement of the mulch. The mulch border clarifies the hand-controlled area visually so that it can be allowed to grow while maintaining an orderly appearance.

The January tasks were thus mainly

-separating dried grasses from dried vine, moving the grasses to sheltered shady spots among tall green plants, or covering small piles with tradescantia.

-compacting of woody waste piles by cutting up long lengths

-disposition of dry Cape Honey Flower wood and foliage to areas of more moisture and shade further from the public walkway

-observation and assessment of future fire hazard presented by exotic herbs being grown for shade and ground cover, which will dry when mature

-trying several different methods of disposing of dry pampas where it will not present a fire hazard near the public access, (none of the methods tried were adequate for the bulk of this material) finally settling on these two strategies:

1. • gathering most of the loose dry foliage into a 2x3m pile about 10-20cm H on the green Annexe lawn, (moist with dew each morning), covering it with a tarpaulin and weighting it with some wooden signboards found discarded in the forest.
2. (For pampas uprooted in the forest) - compacting it by trampling in shady sheltered hollows or the large below-ground hollow of a long-dead tree in the forest.

A mechanical shredder would have made quick work of most of these tasks and provided a compact mulch material. However, we prefer to arrange branched or layered woody and herbaceous material as and where it is most beneficial to seedling growth, forming raised, partially-occlusive mini-canopies over areas of likely seedling germination, disturbing habitat as little as possible while suppressing weeds as needed.

During its decomposition on site, all the weed material is contributing to soil permeability and moisture retention, ongoing weed control and invertebrate diversity. The germination and development of seedlings, both exotic and native, has been observed to be greater in the micro-climates and soil conditions of these areas of onsite weed decomposition, demonstrating both the advantages of having weeds to use as mulch, and the need to develop strategies which both anticipate and monitor successive plant communities, carefully identifying and selecting for ongoing regeneration the most desirable species, native or exotic, from those arising.

In areas where no native vegetation had survived the dense widespread invasion of honeysuckle, blackberry, kikuyu and Cape Honey Flower, compromises had to be made between complete or staged weed removal, and then between exposing the bare clay or mulching it.

We have been delighted that so far events have followed their anticipated course .

The complete removal of weakened honeysuckle and blackberry roots was able to be achieved over most of the area in time to expose clay for seedling germination in Spring.

The areas where weed roots persisted longest had to be kept mulched until late Spring, resulting, as expected, in bare areas exposed to dessication in summer.

However, the support given to benign exotic herbs (wild carrot, oxtongues, Prunella, scarlet pimpernel, Lamium, Stachys, Purpletop vervain etc) through removal of their competitors (docks, bindweed, creeping buttercup) had by the end of January resulted in green coverage throughout the bared clay banks of all but a few small areaxs.

Cape Honey Flower Bank was the most recently released (November/December 2018) from dense shrub/vine weed coverage, so has the largest of these bare areas, and its green coverage is, at the end of January, the shortest (under a metre) and least dense. With the assistance of temporary mulching with weeds to hand, it was rapidly greening under a similar dense herbiage to the earlier-cleared banks, until mid-January when growth and spread were slowed by drought from.

It remains to be seen how the herb cover of all Gahnia Grove's banks will fare in the next few weeks. If there is no rain, new herb development is expected to stop, mature herbs becoming dry enough to need cutting down to avoid fire hazard.

If herbs dry successively during a period of firewatch, they will be cut down individually and compacted to be used as mulch among live herbs.

If there is a mass die-off of standing material, safe disposition of the cut material could be on lower banks in shade or covered with Tradescantia. This will be assessed in collaboration with Parks in consideration of the conditions that prevail at the time.

Posted on February 7, 2019 08:05 PM by kaipatiki_naturewatch