Salt Damage

Talking Trees with Lily and Jad . Welcome to another episode of Talking Trees . Every Wednesday , we dive into the world of practical tree care , current discussions and the challenges faced by arborists . Today In this episode , we will dive into the issue of winter road maintenance , the use of salt and its impact on the trees growing along our roads .

Ever drive by a highway in spring and see those sad brown trees just struggling , it makes you wonder what's going on there . Well , today we're doing a deep dive on roadside planting and , honestly , the silent killer .

Yeah .

We've got some fascinating research actually for the University of Tennessee , and then a really interesting practical guide from the Rhode Island Department of Transportation oh cool . So get ready to get your Otney boots on . We're going to uncover a hidden world of environmental impact here .

So it's kind of a story of two sides . Right , we need safe roads in the winter , obviously . So it's kind of a story of two sides . Right , we need safe roads in the winter , obviously . But using de-icing salts has these consequences that you know . Maybe we don't always see .

Yeah , definitely a tough balance , and the University of Tennessee research it like really gets into the nitty gritty of the science behind this salt damage , and I always thought it was as simple as like salt getting on plants . But it's got to be more than that right .

Oh yeah , it's way more insidious . You've got sodium , a huge part of road salt , and it just misses with the soil chemistry and when that happens it disrupts the balance that trees need to take in water and nutrients . It's , like you know , trying to get a drink from a well that's contaminated . Eventually it's going to take its toll .

And their visuals from this article really make it hit home . Yeah , you see pictures of scorched leaves , stunted growth , and even big old oak trees aren't safe . It kind of reminds you that everything has its limits , I guess .

Totally , and some species get hit harder than others too . The article actually talked about how evergreens are super vulnerable , especially like February March . They even had this picture of a pine tree totally damaged by salt . Needles were completely brown . Why do you think those months are so bad for them ?

Yeah , you'd think they'd be used to it by then . Right , they make it through winter , but then spring comes along .

Well , it's a few things . By late winter , those evergreens have been through months of rough conditions . Their needles are exposed , so they're accumulating salt all that time , and then , you know , when the temperatures start to change in early spring they wake up and they start needing more water and nutrients again .

Oh , so they're sucking up all that salt that's built up in the soil too .

Exactly Throws their whole system off balance . And then bam , you see the damage . Think about it this way Imagine your trees getting hit with a mini saltwater storm every time a car drives by .

Oh , wow , Okay . So it's that constant spray , but instead of like ocean air , it's way more concentrated .

Exactly .

So what is that doing to them ?

Well , that salt coats the leaves , especially on evergreens .

Oh right .

And it's like you know , if someone kept dumping salt water on your house plants , eventually their systems would get overloaded .

Yeah , makes sense .

And for trees that means browning needles dropping early . They can't photosynthesize properly .

There's actually a picture in Clatterbuck's paper . It's called a marginal leaf burn , where the edges of the leaves look scorched . Right and it's like a sure sign of salt damage . It is so , knowing all this , what can people actually do ? Both clatter back Andy that Rhode Island DOT paper had some good tips yeah , and it starts with smart planning .

So when you're selecting trees to plant , you know , think about those salt tolerant species and Kinkos honey locusts . They're the champs .

Yeah , both papers had these lists of super trees .

Of course , if you've already got trees and you're worried about salt , there are things you can do .

Like giving them some armor , right yeah exactly Like .

Think about it this way Distance is your friend Right . The further a tree is from the road , the less salt spray it's going to catch .

Makes sense . 60 feet right , that was the magic number .

Yeah , 60 feet's a good rule of thumb .

Okay , what about irrigation ? One of the papers mentioned that like helping after the winter .

Oh , absolutely . It's like a spring detox for your trees . Flushing out all that accumulated salt from the soil can really work wonders .

It's like giving them a nice refreshing drink .

Yeah , and don't underestimate the power of a good layer of mulch .

Oh right , mulch , I usually think of that for weeds , yeah .

Well , it acts as a kind of a protective barrier between the salt and the tree roots .

Interesting .

So simple , but it's a simple step , but it can make a big difference .

Okay , but zooming out a bit here , it's not just about protecting , like the individual trees , right that Rhode Island study , they really stressed the importance of kind of thinking , bigger picture , right .

Exactly .

Sustainable landscaping .

Especially along road sites .

yeah , yeah , creating whole ecosystems that are more resilient . It reminds me they actually did those case studies , right they did Checking out real life projects . Some of those were successes , right ? They ?

were . Yeah , and those successes really just highlight how important thoughtful design and planning are . For example , TF Green Airport .

They found that trees planted further from the road and on kind of like slightly higher ground were thriving . Getting them out of the line of fire . Exactly what about that project on Route 138 in Jamestown ?

Oh , that one was fascinating . They used a mix of native plants that were , you know , well suited to local conditions , and they actually invested in a three-year maintenance contract to make sure those plants got established .

That's commitment .

It is , and it paid off . The project was considered a huge success , not just for its functionality , but also for how much it enhanced the beauty of the area .

Oh , wow , that's great , but , as you mentioned , not all the projects they studied were quite so successful .

Right right .

So what went wrong in those cases ?

One of the biggest takeaways was that , even if you choose the toughest trees , the most salt-tolerant trees , if they aren't planted correctly or given proper care , especially in those first few years , they're just more vulnerable .

Makes sense . It's like sending a soldier into battle with no training .

Yeah , exactly .

So what could have been done differently ? I remember the Rhode Island paper mentioned something about a plant's natural habitat .

Right . So they stressed , choosing trees and shrubs that were , you know , adapted to similar conditions to those found along roadsides . You know , the Rhode Island paper also talked about how even small details matter , like which way a slope faces .

Oh , interesting . Ok , how does that play into it ?

Well , think about it . A south-facing slope gets more direct sunlight , right .

Right .

That means , the snow melts faster .

Oh , okay .

Which could lead to more salty runoff .

So it all connects .

It's like this whole intricate dance between the sun , the slope , the salt and then the trees .

We need to think like landscape choreographers . Speaking of connecting the dots , I was reading about how the Rhode Island study they really wanted to use a mix of trees , A and D shrubs in their roadside plantings Right , why is that ?

It's about creating layers . Okay , so think of like you know , you know your heartiest , most salt tolerant species as the front line okay they're the buffer . They protect the more sensitive plants behind them like a living shield wall exactly .

It creates this more resilient layered ecosystem that can handle those tough conditions that makes a lot of sense , yeah , but we also have to talk about what we're putting down on the roads in the first place , right ?

Right .

Remember we were talking about those like alternative de-icing methods , like beet juice , like what I put in my smoothies .

The very same . So it turns out , if you mix beet juice with road salt , it can actually make the salt more effective at lower temperatures .

So you need less salt overall , exactly , which means less damage , less runoff .

Potentially yeah .

Are we talking about beet juice as like a secret weapon ?

Well , it's definitely a fascinating area of research and some places have had good results with it . And since beet juice is biodegradable , you know , Right . It could be a win-win .

That's really cool . I'm guessing it can't be as simple as , like you know , dumping beet juice on all the roads . Right , be juice on all the roads Right .

There are always tradeoffs , cost , you know , availability , the impact on water systems . It's complicated .

Yeah .

But I mean that's kind of the point , isn't it ? This whole thing with road salt is like this big puzzle .

We've pretty high stakes , I'd say .

Yeah .

You know our trees , how our communities look , the whole ecosystem .

Exactly , and that's why it's so important to you know , stay informed , ask questions and , just like understand how the choices we make all fit into that bigger picture .

Well said . So . From the science of salt damage to those real world case studies , from beet juice to that essential reminder that it's all connected , that's your deep dive on road salt and trees .

It's amazing what you can learn when you dig in a little deeper .

It really is . Now here's something to ponder as you go about your day . We've talked a lot about choosing the right trees , right To survive those salty roadsides . What if we flip the script ?

How do you mean ?

What if those salt tolerant trees could actually help protect other plants ?

Oh , interesting .

Like imagine creating these natural barriers where other plants could thrive even with all that salt . Food for thought .

Yeah , it really is .

I was really interested in how the University of Tennessee article explained the science behind salt damage .

Yeah .

Because it's not just about the salt itself , is it ? It's about how it messes with what's going on inside the plant .

No , it's definitely more than just the salt being there . They talked about how salt makes it hard for plants to absorb water , so they basically get dehydrated even when there's water around , and it can screw up how they take up nutrients too , so they're practically starving .

Wow , it's rough being a tree sometimes , but I thought it was really interesting how they explained that salt affects different species in different ways . It's not the same for every plant .

Oh yeah , that's so important to remember . They said that some species are really sensitive to the salt spray , for example , but others are more affected by salt building up in the soil and even when the salt hits them can make a difference . Makes sense .

even when the salt hits them can make a difference Makes sense , like with those evergreens getting hit hard in late winter , early spring . They're dealing with that salt buildup and their system is all out of whack because they're waking up .

Exactly . It's just bad timing all around , and that's why knowing all this stuff , these little details , is so important If you wanna choose the right plants , put them in the right spot and make sure they thrive .

So next time you see those trees along the road , you'll know there's a whole lot more going on . Thanks for diving in with us .

That brings us to the end of today's episode , where we explored the impact of road salt on trees and shrubs growing along our roads . Thankfully , through several scientific studies , we've also discussed ways to mitigate this stress , including the use of salt-tolerant species , physical barriers and alternative de-icing methods .