Tens of millions of trees in danger from California drought
California's forests are home to the planet's oldest, tallest and most-massive trees. New research from Carnegie's Greg Asner and his team reveals that up to 58 million large trees in California experienced severe canopy water loss between 2011 and today due to the state's historic drought. Their results are published in Proceedings of the National Academy of Sciences.
In addition to the persistently low rainfall, high temperatures and outbreaks of the destructive bark beetle increased forest mortality risk. But gaining a large-scale understanding a forest's responses to the drought, as well as to ongoing changes in climate, required more than just a picture of trees that have already died.
A higher-tech approach was necessary; so Asner and his team used the laser-guided imaging spectroscopy tools mounted on the Carnegie Airborne Observatory (CAO) to measure the full impact of the drought on California's forests for the first time. They combined the CAO data with more-traditional satellite data going back to 2011.
Their new approach revealed a progressive loss of water in California's forest canopies over the four-year span. Mapping changes in canopy water content tells scientists when trees are under drought stress and greatly aids in predicting which trees are at greatest death and fire risk.
"California relies on its forests for water provisioning and carbon storage, as well as timber products, tourism, and recreation, so they are tremendously important ecologically, economically, and culturally," Asner explained. "The drought put the forests in tremendous peril, a situation that may cause long-term changes in ecosystems that could impact animal habitats and biodiversity."
The team's advanced tools showed that about 41,000 square miles (10.6 million hectares) of forest containing up to 888 million large trees experienced measurable losses of canopy water between 2011 and 2015. Of this group, up to 58 million large trees reached water loss thresholds that the scientists deemed extremely threatening to long-term forest health. Given the severity of the situation, even with increased precipitation due to El Nino, if drought conditions reoccur in the near future, the team predicts that there would be substantial changes to already significantly weakened forest structures and systems.
"The Carnegie Airborne Observatory's research provides invaluable insight into the severity of drought impacts in California's iconic forests. It will be important to bring their cutting-edge data and expertise to bear as the state seeks to address the effects of this epidemic of dying trees and aid in the recovery of our forests," said Ashley Conrad-Saydah, deputy secretary for climate policy at the California Environmental Protection Agency.
Since day one of CAO flight operations, Asner has been engaged with forest managers and officials from the California EPA and Department of Forestry and Fire Protection to inform decision-makers on the severity of forest water losses from the drought and beetle outbreaks. The team's results also helped motivate the California governor's recent proclamation of a state of emergency for dead and dying trees across the state. The latest CAO maps of forest vulnerability were recently transmitted to both state and federal partners.
"Our high-resolution mapping approach identifies vulnerable trees and changing landscapes," Asner added. "Continued airborne and satellite monitoring will enable actions on the ground to mitigate a cascade of negative impacts from forest losses due to drought, as well as aid in monitoring forest recovery if and when the drought subsides."
More information: Progressive forest canopy water loss during the 2012–2015 California drought, www.pnas.org/cgi/doi/10.1073/pnas.1523397113
Journal information: Proceedings of the National Academy of Sciences
Provided by Carnegie Institution for Science
Miti ya California ni moja ya miti ya zamani zaidi duniani, na ni ya juu zaidi duniani. Utafiti wa hivi karibuni uliofanywa na Greg Asner na timu yake unaonyesha kuwa miti milioni 58 ya California ilipata hasara kubwa ya maji ya canopy kati ya 2011 na leo kutokana na ukame wa kihistoria wa jimbo hilo. Matokeo yao yamechapishwa katika Proceedings of the National Academy of Sciences. Mbali na mvua kidogo, joto la juu na milipuko ya wadudu hao waliongeza hatari ya vifo vya misitu. Lakini kupata uelewa mkubwa wa majibu ya msitu kwa ukame, na pia kwa mabadiliko ya hali ya hewa, inahitaji zaidi ya picha tu ya miti ambayo tayari imekufa. Kwa sababu hiyo, Asner na timu yake walitumia vifaa vya laser-guided imaging spectroscopy vilivyowekwa kwenye kituo cha uchunguzi cha Carnegie Airborne Observatory (CAO) kupima athari kamili ya ukame kwenye misitu ya California kwa mara ya kwanza. Kwa mfano, data ya CAO ilichanganywa na data ya kawaida ya satelaiti hadi 2011. Utafiti huo ulionyesha kwamba kwa miaka minne, misitu ya California ilikuwa ikipoteza maji kwa kasi. Kupata mabadiliko katika kiasi cha maji katika matawi ya miti huwaambia wanasayansi ni wakati gani miti iko chini ya dhiki ya ukame na husaidia sana kutabiri ni miti gani iliyo katika hatari kubwa ya kifo na moto. "California inategemea misitu yake kwa ajili ya usambazaji wa maji na kuhifadhi kaboni, pamoja na bidhaa za mbao, utalii, na burudani, kwa hivyo ni muhimu sana kiikolojia, kiuchumi, na kitamaduni, ""Asner alielezea." "Ukaumu huo umeweka misitu katika hatari kubwa, hali ambayo inaweza kusababisha mabadiliko ya muda mrefu katika mifumo ya ikolojia ambayo inaweza kuathiri makazi ya wanyama na utofauti wa kibiolojia. """ Kwa mujibu wa ripoti hiyo, eneo la hekta milioni 10.6 la msitu wa Australia, ambalo lina miti milioni 88 ya ukubwa, limepatwa na upungufu mkubwa wa maji ya misitu kati ya mwaka 2011 na 2015. Kati ya miti hiyo, miti mikubwa milioni 58 ilifikia kiwango cha kupoteza maji ambacho wanasayansi waliona kuwa hatari sana kwa afya ya misitu kwa muda mrefu. "Kwa kuzingatia ukali wa hali hiyo, hata na ongezeko la mvua kutokana na El Nino, ikiwa hali ya ukame itatokea tena katika siku zijazo, timu hiyo inatarajia kuwa kutakuwa na mabadiliko makubwa kwa miundo na mifumo ya misitu ambayo tayari imeharibika sana. """ "Utafiti wa Carnegie Airborne Observatory hutoa ufahamu wa thamani juu ya ukali wa athari za ukame katika misitu ya California ya iconic. "Ni muhimu kuleta data na utaalam wao wa hali ya juu wakati serikali inatafuta kushughulikia athari za janga hili la miti inayokufa na kusaidia katika kupona kwa misitu yetu, ""alisema Ashley Conrad-Sydah, naibu katibu wa sera ya hali ya hewa katika Shirika la Ulinzi wa Mazingira la California." Tangu siku ya kwanza ya shughuli za ndege za CAO, Asner amekuwa akishirikiana na wasimamizi wa misitu na maafisa kutoka EPA ya California na Idara ya Misitu na Ulinzi wa Moto kuwajulisha watunga maamuzi juu ya ukali wa hasara za maji ya misitu kutokana na ukame na milipuko ya wadudu. Matokeo ya utafiti huo pia yalisababisha gavana wa California kutangaza hali ya dharura kwa miti iliyokufa na kuharibika katika jimbo hilo. Ramani za hivi karibuni za CAO za udhaifu wa misitu hivi karibuni zilipitishwa kwa washirika wa serikali na shirikisho. "Mkakati wetu wa kuchora ramani kwa azimio la juu hutambua miti iliyo hatarini na mazingira yanayobadilika", Asner aliongeza. "Ufuatiliaji wa hewa na satelaiti utawezesha hatua za ardhi kupunguza athari mbaya za hasara za misitu kutokana na ukame, na pia kusaidia katika ufuatiliaji wa urejeshaji wa misitu ikiwa na wakati ukame unapoisha. """ "Kutoka kwa utafiti wa ""Progressive Forest Canopy Water Loss During the 2012-2015 California Drought"" (PNAP) na ""Progressive Forest Canopy Water Loss During the 2012-2015 California Drought"" (PNAP) na ""Progressive Forest Canopy Water Loss During the 2012-2015 California Drought"" (PNAP) na ""Proceedings of the National Academy of Sciences"" (PANAS) na ""Proceedings of the National Academy of Sciences"" (PANAS) na ""Carnegie Institution for Science."""