How to Find Specific Trees Using Satellite Imagery

I’ve always loved spending time in the forest, but ever since graduating from college I’ve lived in large cities. While I still get the chance to explore the woods, this meant that I would spend a lot of time dreaming about the next chance to get away.

To be honest, I’ve spent a lot of time looking at satellite imagery of the forests of my youth. I don’t know exactly what I expected to get out of all that time spent dreaming, but it means I’ve happened to stumble upon a few happy accidents along the way.

All of that brings me to this: there are many, many things that you can do with satellite imagery to make the most out of your time in the woods.

In this post I’m going to lay out everything I know about using satellite images to learn more about your forests. A big part of that is getting to know which kinds of trees live where. Fortunately, with a little luck and some help from some satellite images, we can start to make sense of our time in the woods.

Why You Would Want to Find Trees With Satellite Imagery

I’m sure there will be a few people that think this is all a bit silly. If you’re merely looking to enjoy your local forest by going for a stroll down a path, then I completely agree.

However, if you perhaps have more ambitious plans for your connection to nature, then it can massively pay off if you can get comfortable with a few modern techniques and tools.

Like it or not, we’re living in an entirely unprecedented age when it comes down to access to information. If we’re being honest, there are many downfalls associated with this ever-connected world, and, ironically, those ails are often fixed with a good-old forest bath. In an effort to kill two birds with one stone, let’s find a way to use all of this technology for good and to have it help us spend more time in nature.

So, let’s get to it. Here are some of the things that are possible if we learn how to make the most out of the tremendous resource that is our rich collection of satellite imagery:

  • Identify groves of oak trees in order to find a great spot for gathering acorns
  • Locating swamps with tamarack trees, in order to find plants associated with them
  • Finding a cluster of trees that are unfamiliar to you and then identifying them in the field
  • Observing the fall colors of your nearby woods from space, in order to identify groups of like trees ripe for identification

All of these are a great opportunity to find a way to strengthen your ties and connection to your local forest. Join me as we work to make the forest a little less mysterious with some help from modern technology.

Important Things to Know Before Getting Started

Before we get started and dive into the action steps in the rest of this post, please take a little bit of time to closely read this section. The points covered below will do a lot to make this whole process a lot less confusing, and you really stand to benefit.

The Timing of the Imagery Matters a Lot

There’s no way around it; the timing of when the satellite image was taken makes a huge impact on whether or not we can actually use it. Let me explain what I mean: the satellite image of a mixed forest containing both evergreens and deciduous trees interspersed is difficult to use if it was taken during the summer months.

This makes sense as anything and everything in the woods is green come summer, so all you’re essentially looking at are a huge swath of green trees.

satellite image of forest in summer with deciduous and evergreen trees looking similar
This forest does contain a mix of evergreen and deciduous trees, but satellite images from the growing season make this much more difficult to analyze.

For this reason, I much prefer to find satellite images taken anytime between mid-fall and before the leaves bloom in spring. one of the reasons that fall is okay is because we can leverage the different colors that trees turn before they lose their leaves.

For an example of why this is important, see the below screenshot of satellite imagery from Google Maps that uses growing season imagery on the left but leaves-off imagery on the right.

satellite image from google maps showing a blended section with part leaf off imagery and part leaf on imagery
You’ll occasionally run into spots like this that are blended along a border. This may be temporarily confusing, but understand that it happens with modern mapping applications.

The imagery on the right allows us to quickly understand much more about the landscape. It still is possible to draw some of the same conclusions with the imagery on the left, but the difference are much more subtle and can be hard to spot as a beginner.

We can also use the approximate order in which the different trees lose their leaves but more on that later. On another note, you rarely see satellite imagery from winter used with the snow on the ground.

Very Beneficial to Have a Basic Understanding of Your Local Habitats

The most important point that I can make in the section is that it’s precious to have some basic understanding of your local forests and what happens to your trees throughout the seasons.

I think about it like this: satellite images are merely tools that allow us to apply and search for patterns that we’ve already begun to understand.

This is maybe most clearly explained with a direct example. I spend a lot of time in northern Wisconsin in the Nicolet National Forest, and some of the more common trees up there are maple trees, northern red oaks, tamarack trees, and a variety of evergreens.

I know from experience that the maple trees that dominate the woods lose their leaves early in the season and take on a bright yellow color when they do. On the other hand, northern red oak trees in that area tend to hold onto their leaves much longer, and they have a bright orange color in the fall.

So how can we use this information? I didn’t mean to find this, but one day I was looking at satellite images for that local area, and I noticed that most of the deciduous trees had lost their leaves except for some bright orange clusters of trees.

satellite imagery of a forest in fall with yellow and orange trees scattered throughout
I can confirm that the yellow trees on the left are an evergreen swamp with many tamarack trees present, and that the surrounding trees that are orange are northern red oak trees.

The day earlier, I think it was that I had been walking through the woods and found some northern red oak trees and noticed that they still have their leaves and that they were bright orange. This probably won’t come as a surprise, but I sought out to immediately confirm that all of the bright orange dots I saw on the satellite image were, in fact, northern red oak trees.

Determining Deciduous vs. Evergreen is a Great Starting Point

I understand that the above section may have gotten a little into the weeds, but let’s pull it back for a minute and get back to basics.

One of the easiest things that anybody can do when starting to use satellite imagery to better understand their forests is to always think about the deciduous versus evergreen tree question. Going from treating the forest as just a bunch of green trees to starting to think about which locations have evergreen trees versus which locations are mixed or deciduous is a crucial step to take.

leaf off satellite image showing evergreen trees, deciduous trees and national forest trails
We can glean a great deal of information from a satellite image like this. Note that in addition to seeing evergreen vs. deciduous, it’s also much easier to identify trails and the approximate tree density.

It may sound a little superficial, but it’s valuable to have this framework in mind when you’re out in the woods.

Here’s an example of why this is beneficial: if you’re hiking off-trail through the woods and you know that you’re currently in a patch of woods that is almost entirely deciduous trees but surrounded by evergreens, you’ll be able to leverage that knowledge to keep you from getting lost.

This is because you’ll know that if you ever get to a part of the woods where is the makeup of the forest around you switches from deciduous to evergreen trees, you’ve gone too far and need to turn back.

Using Static Satellite Imagery From Common Applications

We’ll start with the simplest approach before we get into some of the lesser-known methods. As you probably can figure out, the easiest way to start using satellite imagery to identify trees is too visually explore the imagery you find on the mapping applications you already use every day.

For most people it doesn’t have to be any more complicated than opening up Google Maps and toggling on the satellite image option in the bottom left corner of the screen. Now, it’s really beneficial for us to branch out and checks some different applications as well. Here’s a list of some of the mapping applications that are worth checking out for satellite imagery:

The mechanics of all this is straightforward. Just load the mapping application and zoom into the forests that you’re interested in learning about. What you want to see is what type of satellite images they employ.

Of the options that I listed above, I find myself using the Zoom.Earth application most often when I’m looking to quickly check out some satellite images without wanting to load a separate application like Google Earth Pro.

There are a couple of reasons why I prefer their tool. First, the default view when you load the app is recent satellite images. There’s not really a whole lot we can do with this, but I think it’s a pretty neat feature. For example, when I’m loading this on October 5th, 2020 you can see that it indicates that the fall colors in northern Wisconsin are definitely underway:

screenshot of application with near real time satellite imagery of northern wisconsin in october

Unfortunately this is as far zoomed in as this recent satellite imagery will allow us, but I think it’s still kind of cool. On the other hand, once we zoom past this point we are met with the best feature of this application. Here we want to look at the upper left portion of the screen, where we can see something similar to this:

screenshot of application showing buttons to toggle on different satellite imagery layers

You’ll notice that we have two different options available, and we can see that we have the ‘May 2017’ option enabled by default. As you can probably guess, this indicates the time frame in which this layer of satellite imagery was taken. If you look at the layer not toggled on in that screenshot, you’ll notice that you may get a time range that isn’t helpful (5 years, really?). That doesn’t really matter; what matters is that we can easily switch between the different views available. Here’s what it looks like when I switch to the ‘April 2011 – Oct 2016’ layer:

screenshot of application showing leaf off imagery of a local forest

By my guess we’re looking at mostly maple trees (as the leaves are gone) with northern red oak trees scattered throughout. There are a smattering of yellow trees shown, but I would guess only those in the lower right are tamarack trees. The yellow trees in the middle of the screenshot are likely a different type of tree, and I would consider this an opportunity to lace up my boots and try some identification come the fall.

Consider Any and All Online Applications That Offer Satellite Layers

Besides the navigation apps used for driving around, you might also want to consider navigation or exploring apps that you use for various activities like hiking or hunting. These apps will almost always have satellite imagery available as a layer, and they might use a different source. You may notice that a few of the different sources use the same imagery in your location.

This Method is a Game of Luck but Worth a Shot

This method is very much, just a game of luck. The kind of satellite imagery you get from these free resources tends to be very high, and it will vary across a landscape.

For example, here you can see a single screenshot from a Google Maps satellite image, where they’ve clearly blended two different image sources here. The portion on the right is from sometime early in the spring, and the portion on the left appears to be summer when everything is green.

screenshot of google maps satellite imagery with blended area between leaf off and leaf on images

This is why it’s important to check out different satellite imagery sources as merely moving over a couple of miles might greatly change what kind of value you can derive from this approach.

Google Earth is Worth a Shot With the Timelapse Feature

While still a free option, you’ll need to download Google Earth if you want to get the most out of it. As all of Google Earth is focused on satellite imagery, there is a lot of potential to gain valuable insight by exploring their library of images.

You may already know this, but at the top toolbar, they have a time-lapse feature that allows you to explore previous satellite images associated with your area. The images do start to appear in black and white the further you go back, but we can still leverage the ability to view a single habitat throughout a couple of different seasons. Here’s what the time-lapse tool bar looks like:

screenshot of google earth highlighting the timelapse button with its slider bar below

The left hand side of the toolbar has a button that allows you to navigate back towards previous layers, and there are hash-marks on the slider where they have satellite images from. I’ve had mixed results with this tool, but it does occasionally come in handy.

Finding Near-Real-Time Imagery of Local Forests

I have to be honest here: I searched for this functionality for a long time, and I didn’t really ever think that I would find it for free. Needless to say, I was very excited to see that a tool managed by the U.S. Forest Service offered the ability to look up nearly real-time satellite images across the entire United States. To me, this is a game-changer, and I plan on using it a lot going forward.

This functionality is found in a tool called ForWarn II, and I have a separate post that goes into great detail as to how to use this tool most effectively. You don’t necessarily have to read that much about using this tool, as we’ll be employing a straightforward method that doesn’t get into any of the other science.

This tool has a couple of different data layers that allow you to view recent satellite imagery. In my experience, the highest quality images come from a layer referred to as ‘ Imagery’ data layer. Unfortunately, this layer is only available to the following seven states located in the Midwest region: IL, IA, IN, KS, NE, OH, WI, ND, SD.

If you happen to live in one of these seven states, you can use the following link to open up this tool with that layer already loaded. Everyone else will use a layer called ‘High-Resolution Sentinel Imagery’, which does a good job though it may not be as high quality. You can open the tool with that option by opening this link.

One thing to keep in mind when checking this near real-time satellite imagery is that you may occasionally run into issues from clouds. If that’s the case, you may want to toggle on and off a couple of the other different layers as they may offer a better solution that is it blocked from clouds. There’s another layer of recent satellite imagery called the ‘Medium-Resolution Landsat 8 Imagery’ layer. As you probably can deduce, it’s not as clear of imagery as the previous two layers.

Recall earlier where we got a distant view of the fall colors from the Zoom.Earth application? Here’s a much closer example of what we can find with the Imagery layer:

screenshot of satellite imagery data layer in forwarn ii application

This is much closer and is much more useful for us, but do note that the date highlighted above indicates that this image is at least a week old.

Practical Examples of What You Can Do With This

All of this being said, the point of this entire exercise isn’t just to sit here on the computer and look at the outdoors through some fancy tool. Doing that defeats the whole purpose of even being interested in the outdoors in the first place.

Instead, we want to make it easier to discover the outdoors and ultimately make sense of it. To do that, we’re going to cover a few real-life examples of how we can use satellite imagery to make discoveries out in nature.

Finding Groves of Northern Red Oak Trees via Orange Fall Foliage

Like I mentioned earlier in the post, I’ve used basic satellite imagery from Bing Maps to identify locations that had large groves of northern red oak trees.

This works because the satellite image I was looking at was taken and compiled after the leaves on maple trees had fallen and before the leaves for northern red oak trees fell to the ground. This meant that every northern oak tree in the area popped with a bright orange color that made clusters of them easily identifiable in satellite photos.

screenshot of satellite imagery showing trees with red fall colors
I can confirm that much of this area is northern red oak trees.

So what can we do with this? Personally, I’ve got a minor addiction to foraging out in the woods, so I’m mainly using this as a way to identify excellent sources for acorns.

Avoid Hiking Through Dense Brush By Using Leaf-Off Imagery

Maybe you’re like me and you enjoy hiking off-trail in a National Forest. Here’s some advice that I highly hope you consider: do what you can to identify the approximate density of the woods you’ll be navigating.

What do I mean by density? I’m mostly referring to how tightly packed a forest feels at the ground level. For example, a young forest that consists of a dense thicket of quaking aspen trees will be almost un-navigable almost any time of year. The left side of the below satellite image is a good example of what this may look like:

close up screenshot of google maps satellite imagery with a dense forest on the left and a mature forest on the right

As you can see on the left side, it’s very difficult to see the individual trees, so you can expect a dense thicket. However, on the right side you can see not only individual trees, but we can make the following observations:

  • The size of the tree trunks are noticeably larger
  • The space between the trees is much greater

As such, I would guess that it would be significantly easier to navigate through the right side. You don’t have to always use this method, but I think it’s important to keep in mind when you’re doing something like hiking off-trail.

I’ve found that Google Maps has the satellite imagery that is most suitable for this kind of up-close zooming, but your results may vary. As you can probably guess, this type of analysis is much easier to do if you have leaf-off imagery like above, as it’s then easier to get an idea of how many deciduous trees are in a location.

Explore Your Local Forests in Fall as the Leaves Change

Using the near real-time satellite imagery from the ForWarn II tool mentioned earlier, We can look for any interesting patterns happening in the forest. At the same time, the trees have their leaves change color.

screenshot of satellite images with trees changing colors in the fall, as seen from the forwarn ii application
If searching this during the fall, you’ll be able to see clusters of trees that are changing colors. This is particularly useful in the early and late portions of fall, as brightly colored trees stand out more.

One of the easiest things to do is find clusters of trees that all look approximately the same in color and then visit those trees to identify them. All in all, it’s simply a great excuse to get out into the woods and learn something while you’re at it.

Finding Tamarack Swamps From Yellow Fall Foliage

Tamaracks are a fascinating tree, as they are, as far as I know, the only deciduous conifer out there. Yes, that means that they lose their leaves every single year. When they do happen to lose their leaves in the fall, the leaves turn a bright yellow, and they are straightforward to spot if you know where to look.

Tamarack trees prefer wet feet and thrive and swampy locations where they may compete amongst evergreen trees. As such, you can expect satellite imagery of tamarack trees in the fall to show them as a bright yellow tree surrounded by evergreens. Here’s about what you can expect an up-close cluster of tamarack trees to look like in the fall:

screenshot of satellite image in fall with tamarack trees turning yellow and surrounded by evergreen trees with a creek running through

As you can see, it’s effortless to identify them, and if we zoom out will usually be a to spot a few additional clusters, like so in the below screenshot:

screenshot of satellite image with clusters of yellow tamarack trees pointed out with red arrows

Final Thoughts

While this post may have been a bit of a bear to get through, I hope you found value in this approach. I think satellite imagery is a relatively straightforward way to draw some pretty neat conclusions in the right hands.

I hope that by writing this more people start to look differently at the forests around them. Only by digging around and pushing ourselves to learn unfamiliar and new things can we take advantage of such great resources.

If you liked this article, you may find these related articles to be an interesting read:

By Drew Meulemans

I've long admired forests and devote much energy to learning about them and exploring. I enjoy sharing what I learn and wish to inspire others to do the same.