B.C. forests no longer car­bon sinks

Sci­en­tists looks to bet­ter man­age­ment of land­scapes to dampen wild­fire ef­fects

Calgary Herald - - CITY + REGION - RANDY SHORE [email protected]

VAN­COU­VER If the cat­a­strophic fire sea­sons of 2017 and 2018 are the new nor­mal, it won’t mat­ter what B.C. elec­tri­fies in its bat­tle for car­bon neu­tral­ity.

In each of those years, wild­fires in this prov­ince un­leashed al­most 200 mil­lion tonnes of Co2-equiv­a­lent green­house gases, or three times the amount of car­bon diox­ide from all hu­man ac­tiv­i­ties, ac­cord­ing to Werner Kurz, a se­nior sci­en­tist at the Pa­cific Forestry Cen­tre in Vic­to­ria.

To re­verse that trend, our forests will need a se­ri­ous de­sign over­haul.

A team of sci­en­tists from the United States and Canada is un­der­tak­ing a four-year part­ner­ship to find ways to achieve emis­sion re­duc­tions from wild­fires through land­scape man­age­ment, fuel load re­duc­tion and the creation of a bio-econ­omy that makes use of for­est waste, the Pa­cific In­sti­tute for Cli­mate So­lu­tions an­nounced this week.

Kurz ex­plains the sit­u­a­tion: The av­er­age an­nual di­rect emis­sions from wild­fires in B.C. dur­ing the 1990s was 6 Mt CO2E — that’s six mil­lion tonnes of green­house gases stated as CO2 equiv­a­lents. In the 2000s, for­est fires re­leased 16 Mt CO2E an­nu­ally. In each of 2017 and 2018, that fig­ure was closer to 197 Mt CO2E, or 33 times more than the av­er­age year in the ’90s.

“Hous­ton, we have a prob­lem,” said Kurz, who was a lead au­thor of sev­eral In­ter­gov­ern­men­tal Panel on Cli­mate Change re­ports on land use and forestry.

Hu­man-caused CO2 emis­sions in B.C. are cur­rently about 64.5 Mt CO2E an­nu­ally, with a tar­get of 38 Mt CO2E by 2030, ac­cord­ing to the pro­vin­cial gov­ern­ment, which has launched a mas­sive pro­gram of elec­tri­fi­ca­tion called Cleanbc to help get us there.

But rather than help­ing us achieve any sort of car­bon neu­tral­ity, our forests are now work­ing against us, through a com­bi­na­tion of pine bee­tle-killed forests and su­per-in­tense fire sea­sons.

“In the ’90s our forests were a net car­bon sink,” he said. “In the next decade, the 2000s, they were smaller sinks and in some cases sources. In the 2010s, forests have been a source of car­bon nearly ev­ery year.”

Long-term trends to­ward higher tem­per­a­tures, lower pre­cip­i­ta­tion and the fre­quency of ig­ni­tion events such as light­ning strikes have us mov­ing briskly in the wrong di­rec­tion.

“We could wait and see if things get worse and maybe 2017 and 2018 will re­peat them­selves, or we could ex­plore ways to do things dif­fer­ently to re­duce the risk of wild­fires, the area burned, and the sever­ity of wild­fires in terms of their emis­sions,” he said. “That’s what this col­lab­o­ra­tion is about.”

The wild­fire and car­bon project is a $1-mil­lion part­ner­ship be­tween Cana­dian re­searchers and the USDA for­est ser­vice to “de-es­ca­late the dev­as­tat­ing for­est wild­fires that are in­creas­ingly oc­cur­ring due to cli­mate change.”

Cer­tain for­est-man­age­ment prac­tices, from fire sup­pres­sion to hurry-up re­for­esta­tion, have con­trib­uted to the dire sit­u­a­tion we find our­selves in today, said UBC forestry pro­fes­sor Lori Daniels, Kurz’s co-prin­ci­pal in­ves­ti­ga­tor.

“We are pay­ing a huge cost in car­bon today be­cause we were so good at putting out fires in the past,” she said. Com­bined with a pol­icy-driven aver­sion to pre­scribed burn­ing, B.C. is grap­pling with forests that are loaded with fuel — fallen nee­dles and dead branches — that lead to in­tense, de­struc­tive fires.

Dense forests may not even be par­tic­u­larly ef­fi­cient at stor­ing car­bon. “What hap­pens if we thin out the for­est and re­duce the stress on those trees com­pet­ing for a lim­it­ing re­source like soil mois­ture?” asked Daniels. “Will the trees left be­hind grow faster and se­quester more car­bon? There is lots of ev­i­dence that un­der some cir­cum­stances, that is the case.”

Re­duc­ing fuel loads and thin­ning the for­est is a time-con­sum­ing and ex­pen­sive task, though com­mu­ni­ties like Kelowna are do­ing just that. But tak­ing fuel out of the for­est will re­quire a biomass econ­omy, some way to make use­ful prod­ucts or en­ergy rather than sim­ply burn­ing it in piles.

“If it is go­ing to be burned, we should do that at high ef­fi­ciency and dis­place fos­sil fuel with a form of sus­tain­able en­ergy,” she said. “Lots of small com­mu­ni­ties are still re­liant on fos­sil fu­els, so these are link­ages that we can make.”

When it comes to re­gen­er­at­ing forests, our ap­proach needs to be more nu­anced than clear-cut­ting and re­plant­ing trees that are prized by log­ging com­pa­nies. Agri­cul­tural style mono­cul­tures may not be the way to healthy forests.

B.C. has been fo­cused on grow­ing back the same species of trees that were har­vested as quickly as pos­si­ble, she said.

Of­ten that means that non-mar­ket broadleaf trees like alder or aspen are weeded out with her­bi­cides to al­low the conifers to thrive. That may be a mis­take.

“We thought that we were ac­cel­er­at­ing through the nat­u­ral stages of re­gen­er­a­tion,” she said. “In truth, we are see­ing re­search that shows those broadleaf trees play a re­ally im­por­tant role.”

Broadleaf species con­trib­ute to nu­tri­ent cy­cling by grow­ing and shed­ding leaves.

They pro­vide pro­tec­tion from grow­ing-sea­son frosts and shade in times of drought, both of which can im­prove the sur­vival rate of conifer seedlings.


Ex­ac­er­bated by cli­mate change, B.C. wild­fires in the last two years have re­leased 33 times the amount CO2 than the av­er­age year in the 1990s.

Lori Daniels

Newspapers in English

Newspapers from Canada

© PressReader. All rights reserved.