the seoa genus has been around for thousands of years these trees are scientific Marvels in many ways they stand unique as a tree that doesn't just survive fire but needs it giant aoas are the quintessential fire evolved species giant Seas need fire to to flourish to propagate um because the the seeds of the giant sequa are these teeny teeny little seeds uh They Don't Really uh tend to root very effectively unless they have a nice clear open mineral soil bed that they fall into and the perfect t
hing to create that that condition of course is a little bit of fire on the ground to burn away all the litter and the dove living symbiotically with the most destructive element to humans these trees Thrive a lot has changed in the thousands of years that they've been around and even more is changing now [Music] the Sequoia genus includes the seoa seant also known as the coastal redwoods seoa dendrin are known as giant Seas both seoa species are native to parts of California yet the varying hab
itats in which they grow have each of them to adapt in different ways redwoods were given this name because of their red bark that beautiful red color that you see in a sequoia Forest is tannin which makes the bark more fire resistant uh the bark is also really sort of light and and spongy the resilience of Giant Sequoia a big part of it is just how thick their bark is they have an amazingly thick bark typically on a big Sequoia it might be 8 in to a foot thick coastal redwoods are found in Nort
hern California as well as some parts of Southern Oregon pre-colonization it was not unusual for them to go 10 to 30 years between having fires they were also accustomed to intense hot fires that would Scorch up into the canopy they come in and burn like most of the understory trees and probably Scorch most of the canopy of the big the big overstory trees but those trees survive they are able to do this because they can resprout when people visit the coastal redwoods they will often see a cathed
ral tree a tree that has sprouted more Trunks from the same route they can even do this up into their canopy as long as some area of their canopy survives it can resprout and continue to grow giant SEO also have the red spongy bark that protects them they are found in the Sierra Nevada range in California prior to colonization they were accustomed to frequent regular fire Cycles in the giant cooa the intervals between fires can be short really short like two or three or four or five years giant
seoa mainly had low intensity ground fires we do have some evidence of of some high severity fires in the past but localized more localized like one Grove or a small part of one Grove showing evidence of a high severity fire but really rarely you know once in in 2,000 years you might see something like that in giant syoya unlike Coastal redwoods giant seoa cannot resprout from their crowns when scorched if they get like 80% of their canopy of the upper uh branches and and leaves killed in fire t
hose trees are going to die and they're not going to resp sprout and come back and that's what's been happening actually in the last uh several years fires across the giant SEO range are becoming hotter and more intense so what changed unfortunately when Settlers of European descent are arrived in this area that relationship between the between the forest ecosystems and fires was really poorly understood and like other Federal Land Management agencies of the time we all fell into this way of thi
nking that fire is bad for the forest we've got to put out all of the fires and then we will be doing the best work that we can to take care of the forest between 1900 and in 1910 it became policy to just stop all burning intentional burning but once you put fires out you take the fire away completely then these these stands really filled in and the understory filled in especially with with so-called shade tolerant trees so you can really see a dramatic difference in some of the old photos from
the very early days to those middle days after that fire suppression policy had been in place for a while suddenly uh The Groves have a totally different character it's a much denser forest with the forest being denser there there isn't enough room for seoa seedlings to grow and the crowded understory provides fire a pathway along which to climb into the canopy early on when I first started working here the main concern was getting fire back into Giant Sequoia Groves because by then we had alrea
dy proven pretty well that reproduction of Giant Sequoia depends on fire and also we're concerned that if you don't have fire you get a buildup of forest fuels you get dead branches Dead Leaves dead logs on the ground and if you get a Century's accumulation of those and then you get a wildfire it can burn too severely realizing the risks of managing for zero fires King's Canyon and Sequoia National Parks began working to add fire back into the area throughout the' 60s some really small prescribe
d burning kind of experimental plots here and there by 1968 we really had something like an actual prescribed burn program established here in the Parks the goal of this program was to work to slowly reintroduce fire in a way that would reduce harm to the trees as much as possible so what makes prescribed fire different than wildfires is you get to choose when you do it prescribed Burns can only happen within a certain temperature range you know you don't want it to be too cold but also too hot
can't be too hot outside to do a prescribed burn the prep work can sometimes take a really long time prescribed Burns take time and resources which has limited the amount of land the National Park Service has been able to cover to return the whole sort of Montana ecosystem to kind of the fire return interval that we'd like to see based on tree ring data we'd want to probably be burning at least about 10,000 acres a year in the time that I've been here we are not coming anywhere close to that you
know a lot of years we're burning maybe 1,000 Acres now it's not just the effects of non-indigenous colonizers affecting the trees the climate crisis is creating drier Summers with consequently hotter fires until we started to see some of these more recent effects of warmer temperatures happening the big thing was the exclusion of fire and what that had done to the forest and now we're layering on top of that changes that we can attribute to warming temperatures 2015 brought a very hot intense
fire to the home of the Giants it swept through with estimates saying it killed a 100 ancient trees before then the most Sequoia we had ever seen killed in a wildfire was 14 big ones and suddenly we're up to a 100 hot fires continued Through The Years with 2020 being one of the worst years for Giant sequa on record there are areas of you know even 100 acres or more where uh every Sequoia is dead and we had never seen anything like that I've been saying for some time that when we start seeing the
old seoa that are 2,000 to 3,000 years old dying in large numbers that will be a very clear sign of extraordinary climate change local tribes are working to keep in place their time honored practices our tribe still does fuel mitigation but it's not so much for like just burning the land off right now it's kind of made a big swing towards like logging slash for replanting they do a lot of thin and release now the National Park Service is dedicated to working on it as well we really are trying t
o redouble down on our efforts to protect Sequoia Groves to just get in and do some fuel's work you know maybe we can't do that prescribed burn that ultimate we really want to do right now but at least we can go in there and we can start prepping these magnificent trees need help and it's a community effort we've already intervened I I think it's fully Justified to intervene now with appropriate methods and right places and right times people are looking for ways to support the Giant Sequoia and
to support ecosystems in general I would always urge everyone to find ways to get involved in fighting climate change uh building yourself as a steward and as an advocate by visiting these places and forming your own relationships with them and knowing more about them despite surviving the test of time the these Guardians face new obstacles in a changing climate while the Sequoia may not become extinct in our lifetime we are losing these gentle Giants trees that live through Nations forming at
an unprecedented rate what we've lost is one of the things that humans find so marvelous about Sequoia we've lost the millennial so many of the big Millennial age Seas if you burn up a 2,000-year-old sequoia you won't get a replacement for 2,000 years [Music] yeah [Music] [Music]
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