Satellite images tell Tolaga Bay disaster story
4 July 2018
Satellite images show how the disaster in the forests at Tolaga Bay on New Zealand’s was a long time in the making. The length of time and the extent of the damage rendered to the East Coast and its vulnerable communities has warning for the government as it plans a new surge in tree planting to meet election-based carbon policies.
The images gained using Google Earth illustrate how land use changes from farming to plantation afforestation and wood harvesting have impacted the landscape around Tolaga Bay, near Gisborne.
Running from 1984 to 2016, the images start out showing a landscape laid bare as indigenous forests were cleared in the previous century, followed by increased planting of fast-growing pine plantations through the nineteen nineties and the rapid deforestation as fast-growing softwood timber was harvested.
Responsibility for disaster around Tolaga Bay and the restoration of the land have become contentious issues since torrential rain delivered widespread flooding in the Gisborne area. Concerns have raised that “slash”, timber left over from logging operations, was forced down the flooded Mangaheia River during the storm
As the images from 2010 and 2016 illustrate, steadily increasing areas of once-forested land have been laid bare, making the area susceptible to quickly eroding in a high-rainfall event.
This pic from Google Maps shows a built of logging slash against a bridge over the Mangaheia River in 2010.
The government did have an opportunity to prevent this scenario from playing out when it privatised forests formerly administered by the then Forest Service in the 1980s. The East Coast Catchment Board, which already administered large areas of eroded land in the region, attempted to persuade the government to let it run the Forest Service’s forests. Arguing against taking a purely business strategy, the then chief soil conservator Bob Miller said the government had a duty to support continued afforestation on the steep hills of the region. (National Business Review, 7 November 1986)
GOVERNMENT RESPONSES CRITICAL
An article in the international journal Unasylvia in 2001 outlined how the earlier governments had responded to a report in 1967 recommending that “a line be drawn between the more fertile pastoral river flats and the critical headwaters, and that the whole of the latter area be afforested, even if this meant taking pastoral land out of production…”
(Source: Rhodes, D. (2001). Rehabilitation of deforested steep slopes on the East Coast of New Zealand's North Island. 52. 21-29.)
A new Forestry Corporation established when the Forest Service was corporatized sawn the highly erodible land as not being economically viable. Although 36,000 hectares had been planted over a 16-year period up until the planting programme ended in 1987, a further 110,000 hectares needed to be afforested. However, it was also noted that downstream control of rainfall flow-off from the pine forests was minor, due to many of the pines being too young, insufficient afforestation and the build-up of water at the river mouth took decades.
A problem for those now seeking to not only find ways to mitigate carbon but also protect downstream land from exotic forest plantation management system is that, as Rhodes stated then, “Neither Pinus radiata nor Douglas fir is suitable for planting with very active gullies” with both providing only suitable peripheral planting.
WOOD REMOVALS SOAR
The start of an East Coast Forestry Project and the subsequent ownership by private forestry companies saw exotic planting increases, as illustrated in the maps from the 1990s onwards. However, as they grew to maturity, the wood from those trees has been steadily harvested in larger volumes. Government data shows roundwood removals from the East Coast/Hawke’s Bay region has gone from 2.23 million cubic metres in 2002 to 5.1 million cubic metres in 2017, or a 45 per cent increase.
However, it should also be noted that the economic benefits of all the trees taken out, deforestation, have been limited in the actual region where originated. In the same period that the trees were chopped down, roundwood/log processing (sawmill, plywood and panel board-making) went from 1.0 million cubic metres to 1.4 million cubic metres, or barely a blip in a 15-year period.
Economic Data and Analysis, Ministry for Primary Industries.
BILLION TREE PLAN RISKS
The Labour Government has launched a plan to plant a billion trees over the next decade along with the re-establishment of the Forestry Service. Already a tug-of-war has started over what species of trees should best be planted. The forest industry has already put a stake in the ground for fast-growing commercial species, although admitting “natives have their place…where commercial timber extraction is not viable or would risk serious loss of soil” to quote Peter Clark, chief executive officer of PF Olsen Ltd.
The East Coast experience suggests that economic imperatives will always come to the fore unless the new forest gold rush is controlled by environmental rather than strictly economic imperatives. Either way, the decision-makers might keep in mind that the ramifications of their decisions will be tracked from space for future generations to ponder.
Michael Smith is the editor of The Mud, a Rotorua-based news web site. He wrote extensively on the forestry industry changes in the 1980s for the National Business Review, was co-author of multi-client studies on the forest industries in New Zealand, South Africa and Latin America, and the publisher and editor of the Southern Hemisphere Forest Industry Journal and Yearbook.