Episode 38: Climate Change


 From the Oregon State University's Extension Service, you are listening to In the Woods with the Forestry and Natural Resources Program. This podcast brings the forest to listeners by sharing the stories and voices of forest scientists, land managers, and enthusiastic members of the public. Each episode, we will bring you research and science based information that aims to offer some insight into what we know and are still learning about forest science and management. Stick around to discover a new topic related to forests on each episode.

Welcome back to another episode of In the Woods. I'm your host, Lauren Grand, Associate Professor of Practice and Extension Agent in Oregon State University's College of Forestry. Just want to give you a reminder that you can visit our website @inthewoodspodcast.org to tell us what you think of the podcast or suggest a topic.

And you can be the very first one to leave a voicemail and hear your voice on our podcast where you ask a question and we'll answer it on the air. But back to today's episode, we're all excited to hear more about how forests and climate change are interconnected.

We're hoping by the end of this episode, you'll have a better understanding of climate change's effects on forests and what we can do to adapt our management to reduce the negative effects of climate change. To help us get through this topic, we've invited Jessica Halofsky. Jessica is the director of the USDA Northwest Climate Hub and the Western Wildland Environmental Threat Assessment Center.

Thanks so much for joining me today, Jessica. Yeah. Thank you for having me. So can you tell us a little bit more about yourself and, um, how you got interested in researching forests and climate? Yeah, so I have a background in forestry and fire. I am a college of forestry, uh, alumni. And as I was doing my PhD work, I was actually working on the Biscuit Fire in Southwest Oregon and also in the B&B Complex Fire in, uh, central Oregon.

Um, started to think more and more about effects of climate change and what that means for forest management. So, uh, I did a, uh, some work with the, uh, University of Washington and the Pacific Wildland Fire Sciences Lab through the Forest Service in Seattle and started to do more work with National Forests on climate change effects and adaptation.

So I've been doing this work in the region for about 15 years now. I've worked with a number of different agencies and organizations doing climate change vulnerability assessments and thinking about how forest management can be adapted to reduce negative effects of climate change. Wow, that's lots of great experience.

I'm so excited to hear how it comes out in our conversation today. So let's start trying to start a little bit basic and get people open to learning more about the climate in general. So how do we know the climate is changing and sort of what evidence exists for that? Yeah, well, I think we've already started to see the effects of climate change in our region already.

We've seen temperatures in the Pacific Northwest have increased by about 1 to 2 degrees Fahrenheit over the last several decades, depending on location. We've seen that snowpack is being reduced, and Uh, especially at lower elevations, uh, we started to see more extreme events like the, uh, the heat dome, uh, large wildfires, and, you know, it's hard to attribute any single event to climate change, but we know these type of events are more likely with climate change, and there have been some studies that have linked events like the heat dome to climate change, showing that they're they're a lot more likely with climate change than without.

Okay, I don't know. Oh, yeah, I just want to clarify. So you're saying that these events occur without climate change, but they're happening more frequently now because of climate change.

Yeah, or they're more extreme, um, like the, like the heat dome event. Okay. Yeah. And then another, another way we know that climate change is happening is through computer models. So we have very complex computer models that simulate the Earth's climate. They're called, um, global climate models. And so they're really good at, at reproducing past climate conditions.

But they're not able to simulate the warming we've seen over the last several decades without accounting for the greenhouse effect. And that's where greenhouse gases trap heat in our atmosphere. And that's another line of evidence. Okay, great. So now that we're sort of on the same page about how, what sort of evidence exists, what, what are some things that now that we've seen sort of from the past or, you know, recent past about what, uh, what's changing with our climate, what can we expect sort of that's coming with climate change in the Northwest?

Yeah, so we're expecting temperatures to continue to warm in the Pacific Northwest. So by the middle of the century, we're looking at about four to five degree Fahrenheit increase in temperature. Uh, by the end of the century, that could be as high as 8 to 9 degrees Fahrenheit increase in temperature, and that's the increase in average annual temperature.

Um, so this depends partly on greenhouse gas emissions. What we do as a society in terms of greenhouse gas emissions, whether we are able to reduce emissions, um, by the middle of the century to keep the temperatures from increasing quite as much. So there are a number of different scenarios where the global climate models are run under to look at a potential range of future conditions.

But, uh, all models agree we're, we're going to see some degree of warming, uh, it's likely to occur in all seasons, but, uh, particularly in summer. So we're, we're, the extremes in heat are likely to be more common. Um, when we look at precipitation, it's a lot more uncertain than temperature, uh, but we're expecting overall there might be slightly more precipitation in fall and winter, uh, and potentially less in summer.

Um, so that could mean higher peak stream flows in the winter, uh, that, that could cause more floods. It could also mean we have drier summers than we already do. Um, we're expecting winter snowpack to, uh, be reduced, as we've already seen this pattern. And so when this happens, we have, uh, less snow, earlier snow melt, and then the water runs off a lot sooner.

And in the season, and then we have lower flows and streams later in the summer. We're so overall, that means we'll have, you know, with higher temperatures, lower soil moisture, lower stream flow, and that means more, more water stress for our forests, woodlands and grasslands. Um, so with, with drier soils, it could mean that we're seeing, uh, lower growth of certain tree species, especially ones that are limited by, uh, low soil moisture in the summer.

And then, of course, we can see, we can expect changing disturbance regimes. So we know that forests are, uh, we're seeing longer fire seasons, larger burns, increased wildfire risk. We expect this to, to continue in the future. Um, you know, we have a number of different models that project future fire. All of them agree we're likely to, to have more in the future.

And I'll note that the current conditions of our forests also affects how climate change will affect them. So, for example, in dry forests on the east side of the Cascades, we've had many decades of fire exclusion, um, that have affected forests, making them, uh, denser and, um, more, more drought stressed in general.

And that means they're more susceptible to drought, uh, large fires and also insect outbreaks. Okay, and then what role do forests play overall in climate change? So, forests influence climate change by their effects on carbon. So, we know trees take up carbon dioxide through photosynthesis, and trees and other forest plants also store carbon in live plant tissues.

So, at the current time, the forests in our country are a net carbon sink, which means they take in... And to store more carbon than they emit. So we hope that that's going to continue to be the case. Uh, but we know that drought, large fires, insect outbreaks all result in the release of carbon. So if these events start occurring more frequently, forests may become less of a carbon sink in the future.

Okay, and then, so, can you go a little bit more into how forests are being affected by climate change that, you know, might affect these cycles? Yeah, we're seeing really the biggest effects on forests and kind of the big catalysts for change are extreme events. So whether that's drought, fire, insect outbreaks or disease and so the changes that result from these events are, they're instantaneous and they're really more extensive than what we expect in the near term from increases in temperature over time.

Um, we, uh, another, uh, factor to consider is invasive plants. Uh, they can really take advantage of disturbances and shifting species, and so we're expecting that they're going to do very well, uh, with climate change, and there's a potential for them to outcompete some of our native species. And we know, uh, outbreaks of tree disease may also, uh, increase with climate change, but it's really dependent on what disease we're talking about and then exactly how our climate changes.

So it depends on the seasonality of, uh, temperature and precipitation changes. But with changes in temperature, we do expect that the habitat for plant and animal species will shift. So in general, we expect species to move upward in elevation and in latitude. So for example, we might start seeing species from California becoming more common in Oregon and increasing in abundance.

And then we also expect that species from lower elevations are going to be shifting to higher elevations. So I get a lot of questions from landowners about if we can we can plant species from California. Is that something that's, uh, recommended by, or is that something that's common that people are doing?

Yeah, no, we're, we're hearing more and more, uh, and more questions about assisted migration. Um, but there are different levels of assisted migration. There's, uh, just moving genotypes around. Uh, and then there's moving species from very far outside of their, uh, historical range into a new range.

And so generally the risks with, uh, moving genotypes around within seed zones or slightly outside of their seed zones are lower than with moving species from completely outside their range to a new range in the future. So, um, different levels, different, uh, you know, different degrees of assisted migration and also different levels of risk with those, those different types of assisted migration.

But we do have, uh, the Northwest Climate Hub does have a, uh, web page on that with a number of different resources related to assisted migration. So I'm happy to share that if that would be of interest. Yeah, great. We'll make sure to put that in our resources section in our, on our website. Um, okay, so I got off topic a little bit, but let's go back to, um, you were talking a little bit about fire and drought and, you know, other disturbances and, um, and that being major ways that forest become affected by climate change.

So how do these disturbances on a large scale affect carbon storage within our forest? Yeah, well, large disturbances result in release of carbon. So with fires, carbon is released when plants and other organic matter is burned. Um, with insects outbreaks, carbon is released when the trees are killed by insects.

And the, and the trees start to decay. So as I mentioned before, if, if disturbance events become more frequent, that could affect whether, uh, forests in a particular region store more carbon than they, they release or whether or not they're a net carbon sink versus a net carbon source. Okay. And what about things like what, what about things about how humans affect the forest?

Things like. Thinning or harvesting operations when we're doing management activities. How does that affect the carbon storage on forest? Well, thinning and harvest also result in the release of carbon. So this happens through the use of vehicles, burning of slash, harvesting trees. And so as wood breaks down after we harvest it, it releases carbon.

But we know that there are, uh, wood products that can store carbon for a fairly long period of time until they start to break down or, you know, go into a landfill. So that's something to consider. Um, and that, that is considered when we do these, um, Carbon, carbon footprints and, and life cycle analyses, um, for forest management.

Um, it should be also be noted that, you know, thinning, hazardous fuel treatments, Uh, although they release carbon in the short term. They can also make our, help our forest be more healthy, they can help prevent high severity fire, uh, they can help prevent large scale insect outbreaks and dry forests. So there's a potential trade off there in terms of carbon storage.

We might have a short term, um, release of carbon through some of these activities, but that short term release could help prevent, you know, stand replacement, uh, high severity fire that would release, uh, a lot of carbon all at once. Right, so you're sacrificing a few to save the entire stand of trees in hopes that overall the the net benefit is is higher.

Is that right? Right? Yeah. So that sounds a little bit like something we can do to try to, um, help diminish the effects of climate change. What are some other activities that we can do to make sure that forests can withstand these effects? Yeah. So, and fundamentally we wanna make sure that forests are healthy, we keep forests healthy that helps them to be more resilient to effects of climate change.

So one way to do that is to reduce existing stressors that we already know exist for forests and an example of that would be, uh, invasive species. So we want to and that are competing for water and resources. So, you know, we could make sure that we, um, get rid of any invasive species and in our forests to help make for us more resilient.

Uh, drought is going to be a big issue with climate change. So there are ways to, um, reduce. The effects of drought. So, uh, we want to make sure, especially in dry forests that we're doing a stand density management, thinning trees, uh, keeping density level where we know the trees are getting enough resources and can be healthy and be more resilient to drought and insects.

Um, think about removing species that are less tolerant of low soil moisture. And let's see, we can think about when we're planting, we might want to think about planting in fall if possible. Making sure we're looking at kind of seasonal climate outlooks, long range forecasts, planting in a time of year that's not expected to be really hot and dry.

Um, let's see, we can think about increasing diversity of species. Uh, even including early successional tree species and do this, um, through thinning or harvesting. And this is, it's kind of the idea of not putting all your eggs in one basket if there's more diversity, uh, in a stand and it's less likely that that stand, uh, will be affected by, you know, a complete stand mortality from drought or a particular insect species.

And then we hit a little bit on assisted migration. That's something to consider, uh, in terms of genetic and species diversity. Uh, we want to think about species that are, um, are appropriate for the site, but also expected to do well in the future in hotter, um, climate, and that they're also tolerant of low soil moisture.

Let's see, for fire. Uh, there are a lot of different options. Thinning is one of them. Reducing understory vegetation. Uh, do doing hazardous fuel treatments. Uh, making sure, you know, bringing the density down. We don't have those ladder fuels that, uh, kind of connect the fuels from the forest floor up to the tree canopy 'cause those can really help to, um, ladder fuels help a fire to spread.

So by, uh, reducing ladder fuels you can help slow fire spread and reduce fire severity if one is to come through. Um, we want to think about favoring tree species that are resistant to fire. So these are Douglas fir, Oregon white oak. Uh, some might want to think about planting those, those species or retaining those species, uh, more in the future.

It's also a really good idea to plan for fire. So if you have a forest management plan, it's a really good idea to think about what you would do if, if part of your forest did burn. Which, which trees might you plant? Um, where would you get your seed? It's, it's good to think through those, those things in, in advance so you, you're less reactive if that does happen.

And if I could just plug that, if you are a small woodland owner, that writing a management, we always recommend writing a management plan. That's a wonderful idea to put that in there. And, um, just being the extension agent that serves Lane County, we had a lot of landowners that unfortunately experienced that.

You know, well, a lot of landowners across the western part of the state experienced that during the Labor Day fires. But this year again is, um, we have quite a few fires in the eastern part of our county. And so, and you know, they're, they're quite a few that happen every year. But having that management plan and being ready for that is, is really important.

And now with the you know, lots of the effects of climate change that you've been discussing today, landowners more and more are saying that the trees that they're planting aren't surviving and they're having trouble getting them established and so, um, having that plan can really help you work through those challenges and, um, think about that seed source and, and getting those trees to, to survive.

So those are great. Yeah, I just want to say those are great suggestions. Right on. Yeah. Yeah, and just a few more, uh, on the kind of insect and disease topic. It's, it's good, a good idea to try to prevent introducing non native insects, diseases to your forest. Um, so, you know, again, the idea of diversity comes up.

If you have more diversity, less likely that your stand will be completely affected by any particular insect or disease. Um, so, and, and again, the, the genetic diversity could play a role there, and yeah, I think those, those were the, were the big ones. Those are the big ones. Yeah, those are some really great suggestions.

Um, are there, are you seeing an increase in any particular insect or disease in Oregon that as a result of various forms of climate change, or are we just in general right now in a preventative phase? Yeah, there are a couple. I think there's a mountain pine beetle. Um, we've seen that primarily in, in eastern Oregon.

Um, and it's affecting species like ponderosa pine and when, when trees are more drought stressed, they're less able to withstand the effects of of an insect like the mountain pine beetle. Um, we're also starting to see more, um, some of you might have heard of this in southwestern Oregon, the flatheaded fir borer, which really didn't used to be a primary, uh, mortality agent for Douglas fir, but we're seeing it more and more.

And particularly, uh, with Douglas fir that are on sites that probably didn't used to be closed canopy forests, they're probably more of a woodland. And, uh, the soils, uh, don't retain a lot of moisture, so they're, they're poor soils for tree growth, and so on those sites, we're seeing quite a bit of mortality of Douglas fir, and it's probably a combination of the, the drought stress and the flatheaded fir borer, um, on those sites.

Yeah, that seems like a really good example of how, um, you know, some of our history of management, like fire suppression, has sort of come back around to this change in climate and now, you know, trees, so Douglas fir is now growing in a place that historically, maybe it would have been excluded from because of, um, more frequent fire on the landscape.

And now, as our climate's changing to create more unfavorable conditions, we're seeing more, more effects. Uh, affected for them there because it's a marginal site to begin with. So, um, it's interesting to sort of see how, uh, well, it's it see how those those various changes are creating different health situations in our, our forests, but maybe that's a good place to start.

You know, if you're thinking about managing a forest and, um, for climate change in mind, uh, do you think it would be a good place to start by looking at places where, you know, you have maybe the more marginal or fringe areas where condition, you have trees in places that there don't historically grow or where they don't always match the resources really well.

Yeah, absolutely. I think it's a really good idea to, you know, look at your forest, look at aspects and, um, you know, concavities is, and think about, you know, what, what species are there now and what species might do well in the future, you know, you might see on those marginal sites. If you have species that are, um, you know, on, on marginal sites for what they need, then that's where we're probably going to see mortality.

And that's where you need to think about, you know, what, what might do well there in the future. Yeah, because it's really hard to to answer those questions from the public and from landowners and see these big pockets of dead trees. And, you know, we have to maybe think, try to think of the bright side and say, "Okay, what can we put there that's going to survive?"

That can withstand these effects. And you had great ideas. So the trees that are more drought tolerant, Um, and increasing the diversity, right? Of trees so that if something comes through that it doesn't kill everything. Um, so yeah, those are really great. Any other, um, tips or tricks that you can think of that, um, when people are out walking around in the forest, is there anything that, you know, really catches your eye typically, and you're just thinking, oh, that you know, that's a forest helping climate change, or that's the forest being affected by climate change.

Oh, um. Sorry to put you on the spot. Yeah. Yeah. Um, I mean, I think it's, it's, you know, our landowners have a great understanding of their particular places. And I think, you know, using that knowledge, being familiar with your forest and what's there now, what changes you're seeing that can, that can all be used to help you figure out what to...

What to do in the future. So, um, getting to know your species, whether you have invasive species or not, um, if you're starting to see mortality and what that looks like, you know, thinking about different microsites. I think that's all, um, super important. And there are a lot of resources out there and I can share some in terms of things to think about with climate change.

Great. Well, we'll make sure to get that list of resources from you in our lightning round. So don't, uh, stop listening yet. It's up next and we'll get all those resources and great things and places to go to learn more about climate change and forests.

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Okay, well, I'm really excited. We got to learn a lot about climate change and climate change's effects on forests.

If there's any other questions you have about how climate and forests interact, don't hesitate to head to our website and let us know what questions you have. And we'll try to Invite Jessica back on or somebody else who's interested in talking about forests and climate to answer those questions for us.

You can put that in the comment or send us a message on our website @inthewoodspodcast.org. Okay, but now it's our opportunity to learn a little bit more about Jessica. Um, so why don't you share with us what is your favorite tree? Well, that's a tough one. It's like asking who your favorite child is, but, uh, I think I'd pick, uh, Pacific Madrone, as I really, I think its bark is, is beautiful.

I also really like, you know, kind of the settings where, uh, where you find it in, in the forests in Southwest Oregon and also, uh, along the coast in Oregon and Washington. Yeah, it's a beautiful tree. And I actually, um, first became acquainted with the tree in Washington and always sat on the rocky, you know, cliffs with salt spray, but it's always in such a different spot here in Oregon, which is kind of cool.

You think about, wow, that tree can handle a lot of a lot. Yeah, yeah, absolutely. Okay, well, um what about, um, what's the most interesting you bring with you into the field when you're doing field work or heading out into the forest? Whether it be a cruiser vest or a field kit or just something you like to carry in your pocket.

Well, I like to bring binoculars so I can do some bird watching. It's one of my favorite things to do. Oh, yeah. That's, that's a popular answer. Lots of bird lovers around. Oh, okay. Not as popular as you would expect. I would think that almost every other person would say that, but it's a, it's definitely a good one.

And, um, I don't know much about birds, but I like to, I've started bringing binoculars so I can try to see more wildlife in general. And okay, so, and here's our opportunity to talk about resources. Um, so what are those resources that you wanted to recommend to listeners about how to dive deeper into, um, how forests and climate change are related?

Yeah, so there are a lot of resources on the Northwest Climate Hub website. So I'd encourage you to go check that out. There are a lot of short pieces on different topics. Uh, and then there's also in particular a forest resilience guide for small forest landowners. It's focused on western Washington, but I think a lot of the principles can be applied in other places.

We're in the process of doing one for eastern Washington for drier forests and then also working with OSU Extension on some other fact sheets for Oregon too. So those should be coming out in the next few months and they'll all be put on the Northwest Climate Hub website.

Yeah, great. And I probably should have done this at the beginning, but just for the benefit of listeners, can you just give us a little bit of a description of what the Climate Hub does? And, um... yeah, so the Climate Hub is USDA wide. Um, so we have 10 regional climate hubs across the country. Uh, five of them are located with the U.S. Forest Service.

Five of them are located with the Agricultural Research Service. So, our Northwest Hub is a Forest Service sponsored hub and so we're located with the Pacific Northwest Research Station and our our mission is fairly broad to promote climate informed management of natural resources.

So that covers forestry and also agriculture. And so we have, uh, you know, put a lot of work into, uh, outreach and synthesis of science, uh, and so that's why there's a lot of focus on our website and we try to put a lot of resources, uh, there. Well, thank you so much for joining me today and sharing those resources and information with us.

Um, I think it's really interesting to learn all about how, you know, forests are involved in climate and their health and how their health can affect, you know, how much carbon storage that they can, um, they can store, hold on to and sequester out of the atmosphere and, um, we can help. You know, we always think about, oh, how, you know, we're just one person.

How can we, how can we help this big, um, existential concept of climate change? And thinking about just if you own forest or even if you visit forests, just the various things that you can do, um, to help in your own way. So thank you so much for sharing that and being here with us. And, um, hopefully it fuels the conversation and we get to talk more in the future about some more specific topic related to forest and climate change.

Thank you so much for listening show notes with links mentioned on each episode are available on our website inthewoodspodcast.org. We'd love to hear from you. Visit the Tell Us What You Think tab on our website to leave us a comment, suggest a guest or topic, or ask a question that can be featured in a future episode.

And give us your feedback by filling out our survey. The In the Woods Podcast is produced by Lauren Grand, Jacob Putney, Scott Leavengood, and Stephen Fitzgerald, who are all members of the Oregon State University Forestry and Natural Resources Extension Team. Episodes are edited and produced by Kellen Soriano.

Music for In the Woods was composed by Jeffrey Hino, and graphic design was created by Christina Friehauf. We hope you enjoyed the episode, and can't wait to talk to you again next time. Until then, what's in your woods?

In this episode, Lauren Grand invites Jessica Halofsky on the show to discuss the impacts of climate change on Oregon's forests.

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