Willows often the 'unsung heroes' of the Gisborne hills

This photo shows one property with mature willow plantings and, for comparison, the following photo in this gallery shows a property with newer willow pole plantings. Pictures supplied

Willows are the 'workhorses’ of Gisborne’s rural landscape and often the unsung heroes, said Plant and Food senior scientist Ian McIvor, who is general manager of the Poplar and Willow Research Trust.

“Every day, willows are working on our behalf around New Zealand,” he said.

“They protect river banks by acting as a buffer to absorb flood water and deflect strong currents from the river edge.

“They stabilise hill sides and gullies, provide food for bees and shade and shelter for stock, as well as fodder in times of drought, not to mention landscape enhancement.”

Mr McIvor said a quarter of the East Coast’s land was susceptible to severe erosion, compared with only eight percent of all land in the North Island.

Erosion was already a serious problem when Cyclone Bola pounded the East Coast with up to a metre of rain over three days in March 1988. Gisborne’s hill country lost three-quarters of its pasture slopes to shallow landslides while silt smothered paddocks, orchards and crops downstream.

“The forest damage was estimated at $8.6 million ($16.8m today) horticulture and farming losses amounted to $90m ($175m). The government repair bill for the cyclone was more than $111m ($216.5m).”

The East Coast Forestry Project promoted large-scale commercial forestry and other sustainable land use changes in the wider Gisborne region. The first plantings in 1993 are now coming up to harvest, he said.

“The project was replaced by the Erosion Control Funding Programme and expanded to include reversion to native bush.

“While more than 96 percent of work done in 1993-2005 was afforestation, since 2000 there has been a big increase in indigenous reversion and space-planted poplars and willows.”

Grants from the programme have seen more than 40,000ha planted in forestry or poles or allowed to revert to native bush since 1992.

“Changes have meant community groups, iwi and other organisations can now also apply for funding.”

Mr McIvor said as at 2012, more than a fifth of the 835,500ha Gisborne District was planted in exotic forest.

“Introduced in 2018, the Government’s Billion Trees programme supports individuals and groups across New Zealand to plant trees or manage land sustainably.

“Direct landowner grant rates are set to encourage planting of native trees, trees for erosion control, and environment-focused planting (MPI website).

“The right tree in the right place still remains a mantra when considering tree planting,” he said.

“In the rush to achieve a grant, landowners should not be planting trees that are unsuitable for the task.

“For example, trees that are slow-growing and have a limited root system are not the ‘right tree in the right place’ if the primary purpose is stabilising soil and preventing erosion.

“Willows are the most effective tree for reducing gully and earth flow erosion. They establish quickly from poles, require no weed control, and their extensive root system is very effective in binding soil and filtering out sediment. New Zealand bred willows are selected for these particular features.”

It’s important to get the right variety of willow, he said.

“The best thing to do is consult your local council or a commercial nursery near you for more advice on clone selection for particular sites or purposes,” Mr McIvor said.

“The experiences of others can save you making bad choices.

“Willows are versatile trees that can be established from cuttings, in species ranging from large trees to small shrubs, and grow in a wide range of habitats.

“They are tolerant of periodic flooding, are great at drying boggy areas and have an extensive root system.”

Mr McIvor said willows can help farmers meet environmental targets around reducing nutrient loss and reducing water pollution.

“The superior ability of poplars and willows to stabilise soils on slopes and gullies as well as around streams compared with native species is due to their much greater root length at the same age.”

The NZ Poplar and Willow Research Trust website, http://www.poplarandwillow.org.nz, has a range of fact sheets and easy-to-follow videos to help landowners make decisions.