FOR­EST TALK

New Zealand Logger - - Contents -

Floods prompt calls to lift our game; ex­perts probe rea­sons for storm flows; forestry op­tions lim­ited on

East Coast; har­vest­ing crews help­ing with flood clean-up; for­est own­ers con­sider bio-se­cu­rity levy; Hult­dins grap­ples sell as Waratah; Kuru crowned king at East­land awards; lower South Island cel­e­brates high achiev­ers; Chi­nese for­est own­ers sign sup­ply agree­ment with North­land sawmill; North­land iwi pledge land for forestry; north­ern rail up­grade stud­ied; Kiwi log­gers help Waratah with new Tim­berRite sys­tem; safety progress un­der the spotlight; ETS changes to help forestry; new CEO for PF Olsen; quick way to lag yarder drums.

THE DEV­AS­TAT­ING FLOODS THAT WASHED thou­sands of tonnes of for­est de­bris down rivers and onto ru­ral homes, farms, roads and beaches north of Gis­borne last month has brought calls from for­est lead­ers for ev­ery­one to lift their game when har­vest­ing frag­ile steep slopes.

The in­dus­try has been sharply crit­i­cised by Forestry Min­is­ter Shane Jones and oth­ers for con­tribut­ing to the es­ti­mated $10 mil­lion dam­age from the flood­ing in To­laga Bay over Queen’s Birth­day week­end.

“The forestry sec­tor has en­joyed a lais­sez­faire set of rules and so­ci­ety’s at­ti­tudes are chang­ing,” Mr Jones told me­dia af­ter wit­ness­ing scenes of logs and slash wash­ing around bridges and sur­round­ing ru­ral homes.

As the clean-up con­tin­ues from the event and the rains that fol­lowed a week later, foresters and the lo­cal coun­cil are seek­ing ques­tions as to why so much de­bris was washed into rivers. And, more im­por­tantly, what can be done to pre­vent it hap­pen­ing again in fu­ture.

Peter Weir, Pres­i­dent of the NZ For­est Own­ers As­so­ci­a­tion and En­vi­ron­ment Man­ager for Ernslaw One, which is har­vest­ing forests on the East Coast, says the events will in­evitably trig­ger a re­view of both har­vest­ing prac­tices and sil­vi­cul­tural strate­gies on land now zoned Red or Or­ange in the re­cently in­tro­duced Na­tional En­vi­ron­men­tal Stan­dard (NES) for Plan­ta­tion Forestry.

He told NZ Log­ger mag­a­zine that the risk of es­tab­lish­ing short ro­ta­tion plan­ta­tion forests on some of the most erodi­ble land in the coun­try af­ter Cy­clone Bola may be “com­ing back to bite”.

But he adds that if ev­ery­one ad­heres strictly to the pro­vi­sions of the new NES then some of the im­pacts in these sorts of events can be pre­vented.

“One of the pro­vi­sions in the NES is for any slash to be moved to above the level of a 1-in-20-year flood, which would re­move it from ris­ing flood­wa­ters in most (but not all) storms, which is where the danger lies. It’s not that slash is be­ing washed down the hill – that doesn’t hap­pen,” he says.

“These sorts of storm events are hap­pen­ing with much more fre­quency and more in­ten­sity, so it re­ally is vi­tal to get that ma­te­rial taken well away. The chal­lenge is to es­ti­mate just where a 1-in-20-year flood might reach.”

Mr Weir sus­pects that some of the de­bris that ended up down river last month might have been logs that were left on steep slopes be­cause they could not be re­trieved in ca­ble op­er­a­tions with­out achiev­ing par­tial log sus­pen­sion. The NES now ef­fec­tively pro­hibits ground-lead­ing be­cause of the in­evitable slope goug­ing and ex­ces­sive soil dis­tur­bance. He says some could be the re­sult of poor plan­ning or poor har­vest­ing meth­ods from the past, as the square-ended stems ap­peared to be at least three-to-five years old.

“It goes right back to har­vest plan­ning and the need to pre­pare prop­erly for bring­ing logs out of dif­fi­cult ar­eas,” he says.

Li­dar now makes new high res­o­lu­tion Dig­i­tal Ter­rain Mod­els (DTM) avail­able to as­sist with de­tailed har­vest plan­ning and “it’s es­pe­cially use­ful for de­flec­tion and pay­load anal­y­sis for ca­ble shows,” Mr Weir says, adding: “I wouldn’t har­vest plan in Red Zones with­out the as­sis­tance of a Li­dar DTM.

“It is equally vi­tal for the fall­ers to make the right de­ci­sion about whether to fall trees in lo­ca­tions that may be im­pos­si­ble to re­trieve – if it can’t be pulled, then don’t drop it. Con­trac­tors need to be in­ti­mately in­volved in this de­ci­sion-mak­ing process.”

For­est man­agers should also be check­ing har­vested sites to in­stall, main­tain and clear well en­gi­neered woody de­bris traps for five or six years af­ter the last trees are cut down, although these can some­times be over­whelmed by the amount of rain in ex­treme events. And wood­lot op­er­a­tors can­not walk away from this re­spon­si­bil­ity in Red Zoned or steep Or­ange Zoned ter­rain.

Mr Weir also says the prac­tice of leav­ing slash over the side of hill-top land­ings will also need to be risk man­aged and says his com­pany is al­ready pulling it back with long reach dig­gers and work­ing to­wards burn­ing it once the har­vest­ing oper­a­tion has com­pleted, as hap­pens in some other parts of the coun­try. There is al­ways the po­ten­tial for poorly com­pacted fill on the edge of land­ings to col­lapse in a re­ally big storm, tak­ing de­bris down the hill, which has hap­pened in the past.

“Burn­ing slash on land­ings takes that is­sue out of the equa­tion,” he adds, though re­source con­sent con­di­tions pre­vent all slash on the slopes be­ing burned.

Mr Weir says for­est own­ers and con­trac­tors work­ing on Red and steep Or­ange Zoned land will need to be much more aware of the like­li­hood of se­vere weather events hap­pen­ing in the fu­ture. It is pre­dicted that large in­ten­sity storms like the one that hit Gis­borne will be four times more likely to oc­cur.

That’s a ma­jor is­sue for the 140,000 hectares of pine forests iden­ti­fied as be­ing planted on highly erodi­ble Red-Zoned land, one-third of which is on the East Coast.

Peter Clark, the soon-to-re­tire CEO of PF Olsen, says Red Zone land re­quires a re­source con­sent, in­volv­ing a Land Man­age­ment Plan to es­tab­lish a plan­ta­tion for­est.

“Con­di­tions may be im­posed by Re­gional Coun­cils, even for a re­plant, that seek to avoid ex­cess ero­sion or de­bris flows at har­vest time,” he says in the com­pany’s lat­est news­let­ter.

“The con­di­tions may cover species, tim­ing of har­vest, har­vest coup size and un­plantable re­serve or re­tire­ment ar­eas. Ri­par­ian or other land deemed too risky to har­vest would be ex­cluded from plant­ing, other than in per­ma­nent species.”

He pre­dicts that the pro­duc­tive area of much of the East Coast hill coun­try will shrink as more land gets re­tired from har­vest­ing and could go into Mānuka, planted for bees to har­vest honey

He adds: “Land val­ues for such land will likely fall and some in­vestors will sim­ply avoid the re­gion, rather than risk ex­tremely costly mit­i­ga­tion mea­sures or com­mu­nity back­lash against forestry.”

NZL

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