By Delwyn Dickey for Our Land and Water
Blessed are those who plant trees under whose shade they will never sit.” John Burke often thinks about that old expression, while planting young trees on retired land on Pukekauri, his Katikati family drystock farm.
In decades to come they will become thriving ngahere (native bush), stabilising the land.
He uses mostly kānuka and mānuka plants, whose strong, flexible and elastic roots hold onto sloping soils, and are early colonisers when land naturally reverts to native bush. Burke is using that process to get new native bush underway.
Kānuka does most of the heavy lifting, stabilising soil and rock in dry sunny areas especially, while mānuka suits moister shady areas. Their roots start building native fungi communities in the soil, such as mycorrhizae. Birds flit between their widely spaced branches, leaving seeds from berries of nearby native tree species behind in their droppings.
The soil fungi help these native tree seedlings to thrive, with the young succession trees eventually growing up through the kānuka and mānuka, as the new forest.
Burke uses the Tīmata method, which uses commercial forestry techniques to establish small plants, about 30cm high, at least 2m apart. The wide spacing gives the plants more room to grow, and cuts planting costs from over $20,000 per hectare (for mixed species at 1.5m spacings) to as low as $3000/ha (using mostly kānuka and mānuka at 3m spacings).
Burke picked up on the approach to regenerating bush on steep farmland while running trials as co-director of Mānuka Research Partnership, to establish mānuka plantations on steep farmland in the North Island 10 years ago.
Regional councils in the Bay of Plenty, Waikato, King Country and Hawke’s Bay are all starting to consider the Tīmata method for planting at scale, Burke says. The method is also being promoted to land and water catchment groups including Kaipara Moana Remediation, Wai Wanaka, King Country River Care, Maramarua-Mangatangi, Wai Kōkopu, Project Parore Catchment Groups and also Tane’s Tree Trust.
Burke was part of a team lead by Dr Alison Dewes, owner of sustainable farming consultancy Tipu Whenua, who looked into benefits of the method with funding from Our Land and Water National Science Challenge.
The newly released planting guide is one of the educational resources developed from that research.
Burke now talks to farming groups with members looking at the benefits of potentially retiring steep, unproductive or erosion-prone land, and wetlands.
A lot of poor-performing farmland simply isn’t contributing to farmers’ bottom line, he says. “While flat easy country might grow 12000+ kg of DM/ha, that steep country is probably only producing 4000kg of DM/ha. When looking at the energy value in that grass, poor utilisation from roaming stock, more labour, gorse control, higher stock losses, and lower lambing percentages, it may be making you nothing, and in some cases a loss.”
Regenerating into native forest and getting income through the Emissions Trading Scheme may be a better option.
“So, the lights are going on with some farmers – they can de-stress, take the pressure off themselves, do environmental good,” Burke says.
“A lot of wins – helping their business but also their wellbeing.”