Showing posts with label plant. Show all posts
Showing posts with label plant. Show all posts

Tuesday 17 March 2020

Using poroporo as a nurse crop

Mt Chocolate is being used for a great big experiment to find faster and cheaper ways to establish native forest. Since mid-2017, different ways to propagate, plant and maintain native plants have been tried out.

Some ideas have worked and some have failed and lots of lessons learned. But each year the methods have been tweaked and progress is being made.

One series of experiments have been underway to find out if poroporo could work as a cheap and reliable nurse crop. A nurse crop is a bit like a scab. When you cut your finger, a scab helps with the healing but is only temporary.

Mike was told repeatedly by many people who plant natives that using poroporo would never work. In fact, it can work really well, but only if the right technique is used.

Mike has found out that poroporo can be used a bit like gorse, to provide shade from the sun and shelter from the wind for small native trees to get established. The idea came from learning from Hugh Wilson of Hinewai fame who is an advocate for using gorse as a nurse crop in certain situations.

It took a lot of trial and error to learn how to propagate poroporo correctly with careful seed treatment, sowing and then very specific planting methods. There were lots of failures involving around 5 litres of seed over the last 3 years.

The jury is still out on site preparation. Poroporo like warm soil in summer, and lots of shady weeds around its roots once it emerges up to the sun. 5-6 trials have been underway this summer to refine the existing technique to optimise success.

Winter at Mt Chocolate can mean frosts which damage poroporo plants. The roots are frost-sensitive and plenty of weeds, grass or mulch around the base of each poroporo is required by end of May.

Shade-loving trees and ferns are then planted under the poroporo, and poroporo can also be planted between trees that don't mind a bit of shade. Spacing and timing seem to make a big difference.

In the most successful test plots, within 12 months from the planting of poroporo, shade and soil moisture levels in summer are allowing for moss and ferns like "common pig fern" (Hypolepis ambigua) and Blechnum to self-establish  No lichens have been found yet on branches.

In the most successful plot of all, the poroporo bushes are 1 year old, 3m tall and ideal ground conditions have been created.  In other plots, poroporo plants might be 3 years old and only 1.5m high. The main problem here was plant spacing too far apart. Spacing too close has also led to poor results.

Regeneration is now kicking in with small seedlings emerging including native and weed species. Here are some photos of native trees emerging out of poroporo at Mt Chocolate.

450 poroporo were planted this summer. 2000 native trees and grasses will be going in this winter. Nursery production will then start to scale down with the emphasis on variety of niche species rather than bulk numbers of a few species.

Monday 15 April 2019

Drone over Mt Chocolate

Mt Chocolate was filmed using a drone at 2pm, 23 March 2018.

The drone was flown by a friend of a neighbour. Thank you, mystery pilot, whoever you are.

Saturday 6 April 2019

What Drives Forest Regeneration

A native plant restoration workshop attended by 70 people was held on Friday at the Invercargill Working Men's Club in the morning. A trip out to Otatara Community Nursery followed in the afternoon.

There is a report here.

I went to the workshop and learned a great deal about some very interesting trials and experiments underway around NZ to find faster and cheaper ways to get native ecosystems established. It was the best workshop/bus trip/field day I've been to since moving to Southland in 2014. It had a lot of meat in it. Hopefully, there will be more like this in future.

Her talk asked the right questions and is based on a monitoring programme of 20m x 10m plots around NZ measuring;
  • Basal Area.
  • Canopy Openness.
  • Soil Temperature Fluctuation.
  • Herbaceous Weeds.
  • Humidity Fluctuation.
  • Tree Regeneration Density.
  • Epiphyte Density.

There are a number of these plots around Invercargill. Here are 3 of Dr Wallace's slides from the talk.

Tracy and I are currently establishing a monitoring programme at Mt Chocolate to watch and study what happens over time as the bush regenerates and evolves into a Miro Swamp Forest. And we are also doing a lot of experiments with different propagation, planting, and maintenance methods to see what works best.

There are 3 broad zones at Mt Chocolate.
  • The north end is sunny and dry with thin clayish soil.
  • The middle is shady, cold, wet and sheltered from the wind with deep peat soil. It floods a lot in winter.
  • The south end is exposed, damp and windy with organic soil.

Adding a plot in each zone similar to the People Cities Nature programme could add a lot of insight into understanding natural processes present. A friend Matt is going to help with setting up the plots in winter. We will have to make up some gadgets as well to help make the measurements. Aunty Google will no doubt come up with plans for gadgets.

The afternoon field trip to Otatara visited a plot at Bushy Point and the Community Nursery. It was a really useful day.

Wednesday 26 December 2018

Recording observations using a phone app

Photos taken of plants and animals found at Mt Chocolate are being used to discover what is living there now.

We are using a very easy tool called iNaturalist to help do this. It is a free app that can be downloaded onto a mobile phone and then be used to take photos. Some simple notes are added in the field at the time. The app then uses automated machine learning to guess what the plant or animal is. Other people using iNaturalist can also help work out what the correct name is.

So far 55 different observations have been made and most have been correctly identified. These include lots of the different weeds growing at Mt Chocolate and the growing number of native plants that have been planted.

The observations can be seen at

Onion Orchid
5 finger

Tuesday 11 December 2018

Mt Chocolate Nursery

Mt Chocolate has a native plant nursery to propagate and grow 220 different species to plant at Mt Chocolate over time. The nursery does not sell plants to the public. Though we are happy to swap surplus eco-sourced seed with other propagators.

This year's production target is 2000 plants ready to plant next year.

Currently being grown is;