Wild­ing conifers could take over

Manawatu Standard - - Nz Farmer - Pat Deav­oll

Take the drive west of Christchurch to the Cas­tle Hill Basin and just be­fore the Craigieburn cut­ting you could be for­given for think­ing the apoc­a­lypse had struck.

Row upon row of tall, dy­ing conifers reach sky­ward, their bleached spars ragged across the hori­zon. Some have be­gun to top­ple, lean­ing pre­car­i­ously against their neigh­bours. Oth­ers have al­ready suc­cumbed to their fate and lie prone across the moun­tain­side. But this scene is not some af­ter­math of a dis­as­ter; it’s the prod­uct of the Gov­ern­ment’s $16 mil­lion pro­gramme to rid the coun­try of its No 1 one pest. Wild­ing conifers.

Ac­cord­ing to the De­part­ment of Con­ser­va­tion (DOC), 5 per cent more of the high coun­try is be­ing cov­ered by wild­ings ev­ery year, and a fifth of the coun­try could be taken over within the next 20 years if dras­tic ac­tion is not taken. It’s that bad.

Due to early ne­glect, the spread of wild­ing conifers has in­creased ex­po­nen­tially since about 1990. The ar­eas of es­tab­lished, thickly wooded wild­ing for­est are still rel­a­tively small – a few hun­dred thou­sand hectares. But an­other 1.5 mil­lion hectares is now lib­er­ally sprin­kled with seedlings and saplings.

Grow­ing in the wrong place, wild­ings out-com­pete na­tive plants and wildlife, re­duce pre­cious wa­ter re­sources, smother valu­able graz­ing land and har­bour pests. They also change the unique char­ac­ter of iconic nat­u­ral land­scapes such as our high coun­try, says Wild­ing Conifer Pro­gramme man­ager Sher­mon Smith.

‘‘Wild­ings are trans­for­ma­tional in their im­pact, and we are at a tip­ping point.

‘‘In prevent­ing the spread of these trees, we must act now as de­lays will quickly put the costs be­yond our reach.’’

But heart­en­ing news: Over the past three years the first phase of the Wild­ing Conifer Man­age­ment Strat­egy 2015-2030 has erad­i­cated over half a mil­lion hectares of wild­ings and searched the sur­round­ing land for re­mote out­liers.

‘‘The pro­gramme is mak­ing ex­cel- lent progress,’’ Smith says. ‘‘The op­er­a­tions to date have ex­ceeded phase one tar­gets.

‘‘As of July 2018, just two years into the four-year pro­gramme for phase one, op­er­a­tions are al­ready 85 per cent com­plete. Within the 1.5 mil­lion hectare area cov­ered to date more than half a mil­lion hectares has been con­trolled. We have also searched over a mil­lion hectares for any re­mote out­lier trees.’’

The Waimakariri Basin, of which the Craigieburn area is part of, is one of the suc­cess sto­ries of the first phase, Smith says.

De­spite a pre­vi­ous spend of $300,000 a year, the gov­ern­ment and lo­cal groups strug­gled to con­tain wild­ing spread from old ero­sion con­trol plant­ings from the 1950s to 1980s. The spread threat­ened pro­duc­tive farm­land, and recre­ational ar­eas and was a blot on the land­scape.

About $2 mil­lion of wild­ing con­trol pro­gramme funds al­lowed a con­cen­trated ef­fort to get on top of the prob­lem and now farm­ers have re­gained use of their pas­toral land and Arthurs Pass Na­tional Park and Korowai/ Tor­lesse Tus­sock­lands have been pro­tected from in­va­sion.

Fur­ther south, a mas­sive 137,000 hectares of the God­ley area of the Macken­zie Basin has been cleared of wild­ing conifers.

‘‘If the [Macken­zie] Basin is taken over by wild­ings, that’s 50 cumecs drained out of the Waitaki sys­tem, the bio­di­ver­sity would suf­fer, and there would be a lot of species that wouldn’t sur­vive,’’ Smith says.

‘‘Ini­tially, it’s scat­tered trees, but they don’t stay like that. In high­den­sity ar­eas – there is no graz­ing un­der­neath them, they can’t be walked through, and this af­fects farming, recre­ation and im­pacts wa­ter yields.’’

Re­tired Scion re­searcher Nick Ledgard is a strong sup­porter of wild­ing con­trol. The threat from wild­ings has been around for a long time, he says, es­pe­cially with species that have eas­ily blown seeds.

He says there is no doubt wild­ing spread needs to be cur­tailed.

To take them out now as young saplings is go­ing to be a lot cheaper than wait­ing un­til they are a solid mass of ma­ture trees.

Ae­rial boom spray­ing on wild­ing conifers on Pukaki Downs in the Macken­zie Basin.

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