Foraging National Forests

How to Find Forests That Were Recently Logged

Admittedly, this probably isn’t a topic on the forefront of most people’s minds. Why would you want to find public land that was recently logged? Seems a bit odd at first.

I’ll get right to it: this is for nature lovers with a bit of a long game. Land that’s undergone logging does require some time to heal, but the healing happens fast. And with that healing comes all kinds of opportunities to watch how nature works over a relatively short time frame. From colonizing blackberries to fruit and nut bushes that have a hard time existing in a mature forest, there’s plenty of interesting things happening in young forests.

Our job here is to find the young forests that you’ll enjoy in the years to come. How can we find locations where logging has occurred or is ongoing? This post will cover a few different methods, and we’ll use all of the tools at our disposal.

Different Methods to Find Recently Logged Land

Before we get into the finer details about how to find recently logged land, I think it would be helpful to briefly discuss why this knowledge would even be valuable. I’ll go into greater detail at the end of the post, but here are a few reasons why a forest lover should be interested:

  • Finding areas with differently aged forests often creates the greatest opportunities for wildlife
  • Younger forests allow for different plant species than more mature forests
  • All forests age with time, so being aware of newly logged land may help you greatly in the near future

With all of that said, let’s get into the details of how to find logged land, then we can later discuss the why in more detail.

Accessing Forest Service Logging Records for National Forests

There’s a mapping application provided by the U.S. Forest Service that I’m going to be using a lot in this post. The application’s name is ForWarn II and it serves a wide variety of purposes, but it’s mostly used to scientifically measure the changes in our forests over time.

The ForWarn II application has many, many data layers available, and one of the most useful layers is the Forest Service logging records. These records go back 20 years and they provide the following types of details on historical logging activity:

  • The specific parcel that was logged, including an outline on the map
  • The total acreage logged
  • When the logging occurred
  • What type of logging was done (clear-cut, commercial thinning, etc.)

Before we get into step-by-step instructions on how this works, there is one caveat about this method: you’ll only be able to find logging activity on land managed by the U.S. Forest Service. So if the logging took place on National Forest land, you’ll be able to find information on it. But all other lands are not covered by this method.

Alright, now onto the actual tutorial. The ForWarn application allows users to share their exact map with a custom URL, so I’m going to save you unnecessary work by sharing my map I’m starting with: here’s the link.

screenshot of the home page of the forwarn ii application
Upon opening the link, this is about what you should see.

There’s admittedly a lot going on here, but here are the key points to understand:

  • The menu on the left is for the Map Layers, this is where we toggle data layers
  • The menu on the right contains the Legend for the visible data layers
  • You can see specs of color throughout the map, these are locations with U.S. Forest Service logging activity (more on that later)
  • The base layer for the map is set to ‘Imagery’

First, we’re going to want to navigate the ‘Map Layers’ menu to find the layers that we’re most interested in. Go over to the left menu and scroll up until you see the following:

screenshot of the map layers menu for the real-time change maps in forwarn ii application
By default, ForWarn II opens up to the ‘ForWarn II Near-Real-Time Change Maps’ layer group

You can see that we’re in the layer group as highlighted above. This isn’t where the logging activity is stored, so we’re going to want find a different layer group. To do so, click on the highlighted ‘ForWarn II Near-Real-Time Change Maps’ toggle and then the menu should be updated into the following:

screenshot highlighting the additional assessment maps for the forwarn ii application

See the ‘Additional Assessment Maps’ layer group the arrow is pointing at in the screenshot? That’s the layer with the Forest Service logging activity. Click on that option and then scroll down until you find the ‘USFS Logging Activity’ sub-group, which should look like this:

screenshot of the us forest service logging activity data layer in forwarn ii application

There are two things that you’ll notice:

  • The ‘2000-2021 Combined (FS)’ data layer is toggled on
  • The rest of the data layers correspond logging activity for individual years

As you may have guessed, the data layer that is toggled on corresponds to the specs of color that you see throughout the map. What these specs of color indicate is that this piece of land had logging activity by the U.S. Forest Service at some point in time.

For example, I’ve zoomed into Michigan’s Upper Peninsula and this is what I see:

screenshot of the data from the us forest service logging activity layer with all years turned on in forwarn ii application

Each of the different colors present represents a different year of logging activity. There are two ways to find out which year the color represents. First, you can go to the ‘Map Tools’ menu on the right and expand the ‘Legend’ option. Upon doing that, this is what you would see:

screenshot of the legend for the us forest service logging activity data layer in forwarn ii application
Each year has it’s own color on the map

You would then match up the color on the map with the color in the legend. This can work, but the major issue is that some of the colors look too similar for my tastes. This doesn’t seem to be an issue at first glance, but if you scroll down you can see how similar the 2004 and 2019 colors are.

Instead, I prefer to find which year the data represents by using the ‘Information’ button in the top toolbar. Turn on this setting by navigating to the top menu and click the highlighted button:

screenshot with a red arrow pointing to the information button in the toolbar for the forwarn ii application
If it is difficult to see, the button is the text bubble with an ‘i’ in it

What this allows us to do is click anywhere on the map and pull up all of the information associated with that part of the map. Here’s an example of what I’m talking about: when I click on the location represented by the yellow dot below, you can see it pulled up a window with information:

screenshot showing the information bubble showing information on the year of timber harvests for the usfs data for a specific location in forwarn ii application

Take a look at the information highlighted in the above screenshot. As you can probably guess, what this is telling us is that the logging activity associated with this piece of land took place in 2019.

Unfortunately, this screenshot also highlights two main deficiencies associated with this data layer:

  • We have access to very limited information about this logging, only the year is available
  • The outline of the area on the map is pixelated, and therefore not accurate to the land actually logged

So, what can we do to get a better idea of what happened here? All we need to do is find the appropriate layer in the Map Layers menu. To do that, first toggle off the ‘2000-2021 Combined (FS)’ data layer. Then, scroll down to the ‘2019 (FS)’ data layer and toggle that on. After completing that, my map changed to the following:

screenshot of the vector layer depicting the individual year logging activity data for the us forest service data layer in forwarn ii application

As you can see, the outline for this data layer is much more accurate, and it represents the actual land that had logging activity in 2019. If I want to learn more about what happened, I simply click anywhere on one of the pieces and I’m presented with an information window like so:

screenshot showing data records for a shape in the us forest service logging activity data layer in forwarn ii application

While I certainly didn’t plan it, here’s a great opportunity to point out the one major caveat I have with these Forest Service data layers: not all of the information fields have accurate data.

This is not a deal breaker, it just means that there may be some years where you don’t have access to the finer details of what logging activity occurred.

Here’s an example of what a complete information set looks like for a single year data layer:

screenshot showing data records for a shape in us forest service individual year logging activity data layer in forwarn ii application

Here you can see that this parcel of land was clear-cut in 2009, and the logging completed on September 22nd, 2009. It also indicates that this parcel is part of the Chequamegon-Nicolet National Forest.

Looking for parcels of land that have been clear-cut? You may be having a bit of a difficult time, depending on where you are searching. In my experience (based in the Upper Midwest), little of the logging performed by the U.S. Forest Service is clear-cutting. Most is either single-tree selection cutting or commercial thinning operations.

While the screenshot above does indicate a clear-cutting operation, understand that this logging occurred once a tornado devastated this patch of forest. So this might be more accurately considered a salvage operation.

Everything considered, I still believe that these data layers showing the logging activity of the Forest Service to be very relevant, they just have a few limitations.

For the Nerds: Severe Drops in Vegetative Productivity

I’m not going to lie to you: while incredibly useful, this next method may appear a little overwhelming at first glance.

While there is a lot of science that goes into this method, understand that we only need a rudimentary understanding of the science in order to employ this effectively.

With that being said, I think it would be most helpful for your to check out this post explaining the ForWarn II application if you would like to use this method.

Brief Explanation of How This Process Works

Before we get into the mechanics of how this works, I think it’s valuable to have a high-level discussion on the method itself.

What we’re trying to accomplish can be essentially broken down into two steps:

  • Identify land with a large drop in the Normalized Difference Vegetation Index (NDVI)
  • Confirm whether or not that area has been logged with recent satellite imagery

What on earth is an NDVI? You might want to check out this post if you want a more detailed explanation, but here’s the gist of it:

The NDVI is more or less a measurement of the level of photosynthesis occurring on a unit of land at that time. A mature forest in early summer has a high NDVI, while land recently logged has a very low NDVI.

As you can probably guess, the NDVI patterns for mature forests are very predictable year over year. This means that the act of clear-cut logging land produces a steep drop in NDVI, when compared to the expected values of the former forest.

Finding Areas with Drastic Drops in NDVI Values

Alright, let’s get to it. Here’s how we can use ForWarn II to find land that has been recently clear-cut. Unlike the previous method, this works for all lands monitored by the ForWarn system.

Like the last method, I’ll give you a head start by providing a link to the exact map that I’m viewing. There’s only one caveat here: the data layer featured is updated every 8 days and is a measure of the current NDVI levels. Therefore, the map you’ll load should be different, as my view is specific to the time of my writing this (late September 2020).

Given all that, here’s about what you can expect to see:

home screen with ndvi results shown in the forwarn ii mapping application

Regardless of when you load this map, the reality is that there’s a lot going on here. Let’s break it down, piece by piece. First, the colored dots you see represent how the current NDVI levels change from the 90th percentile levels over the last ten years. As you can probably guess, the dark red color represents a large drop in vegetative productivity.

It’s important to note that a large drop in vegetative productivity can occur for many reasons, and this is why the ForWarn tool is so useful to so many different people. Not just indicative of logging, the red areas can be in response to any of the following activities or events occurring in a forest:

  • Damage from a storm or tornado
  • Excessive flooding affecting tree growth
  • Wildfires burning

And so on. Here’s a great example of this: at the time of this writing wildfires are currently ravaging large areas of California’s forests. As you’re reading this in the future, I don’t know how this all turned out. What I can say is that this data layer does an incredible job mapping out the extent of the damage done. Here’s a screenshot of the Bay Area, which is being hit particularly hard:

close up screenshot of ndvi damage mapping for california wildfires in the forwarn ii mapping application
Notice the dark red areas south of San Jose: these forests have an almost 80% drop in NDVI values when compared to past years.

Okay, now back to logging. If you live in a forested area that isn’t currently being greatly impacted by a natural disaster, we can use this map to find some possibly logged areas.

On my map I’ve zoomed into the Upper Peninsula of Michigan, and this is what I see:

ndvi damage map of northern michigan with a red arrow pointing to cluster of red pixels indicating heavy damage

I’m going to focus on the cluster of red pixels the arrow in the above screenshot is pointing at. Now that I’ve located a piece of land that I’m interested in checking out, I’m going to perform the following moves:

  1. Zoom in close to the red cluster of pixels
  2. Toggle off the NDVI data layer
  3. Observe the satellite imagery from the base map
  4. Toggle on a layer showing recent satellite imagery

Here’s how this looks, step-by-step. First, I’m zooming well into the cluster of red pixels:

up close ndvi pixel values overlayed over a satellite image
Each pixel covers more land than you might think, so you’ll probably want to zoom in closer than expected.

Next, I go over to the ‘Map Layers’ menu and toggle off the highlighted data layer, which can be found in the ‘ForWarn II Near-Real-Time Change Maps’ data layer group:

screenshot of the 10 year 90th percentile ndvi drop toggled on in forwarn ii application

Confirming Logging Activity By Comparison of Satellite Imagery

Once that data layer is toggled off, I observe what the satellite imagery of the base map looks like. Here’s what I see:

screenshot of satellite image of forest prior to logging

I know that this satellite imagery is from a colder time of year where deciduous trees don’t have their leaves, so I can see that this is likely a plantation of pines or some other evergreens.

Now that I understand what this area looked like in the past, I want to see how this compares to the near-present satellite images we can access in ForWarn.

When it comes down to finding recent satellite images in ForWarn, there are really three different options. Here are the options, in order of quality from worst clarity to best:

  • Medium-Resolution Landsat 8 Imagery
  • High-Resolution Sentinel Imagery
  • Imagery

I should note that the ‘ Imagery’ data layer is only available to the following states: IL, IA, IN, KS, NE, OH, WI, ND, and SD. If you live in an area that does not have the layer, check out the Sentinel layer next.

As the location I’m checking out is in Michigan, I’ll be using the Sentinel imagery. Here’s what I find when I toggle that layer on and let it load:

recent satellite image of forest after clearcut logging

Would you look at that! While I haven’t been able to physically confirm that this area has been logged, I can confirm that this is consistent with other logged areas I’ve visited.

As cool as all of this is, it does come with one major caveat. Please understand that simply finding logged land does not mean that you have public access to check out that land. That’s an entirely different question, and you’ll have to do the research to determine if you have access.

With that being said, I hope that you found this as valuable as I believe it can be.

Be on the Lookout for Logged Land While Out and About

While this isn’t necessarily a separate method, I do think it’s important to park this idea away in the back of your mind. If you live in a forested area and you start to notice logging trucks hauling away trees, it may be worth looking into.

Obviously, I would never recommend that you drive around chasing logging trucks, but keep the thought in mind. It’s always helpful to understand how the forests around you are changing.

You also can look out for the impact of logging on the land, not necessarily for the logging trucks themselves. To give you a better idea of what I’m talking about, I’ve included some photos of recently logged land.

This land was logged earlier in the year, as you can tell that plants have yet to come back from the machinery’s impact:

On the other hand, this is what some National Forest land looks like after healing for a year:

The Benefits of Finding Recently Clear-Cut Land

You’ll notice that the land from the last picture is much greener. I believe that is primarily wild raspberry plants, in the form of first-year canes. I look forward to confirming that classification next year, possibly in the form of buckets and buckets of raspberries.

I hope this point illustrates why I’ve generally taken a neutral stance on logging in this piece. Regardless of how I feel about logging, if the land is to remain wild then nature will begin it’s reclamation process in no time. So in my mind it’s not necessarily about good or bad, but instead about making the best of the situation.

Habitat Diversity Can Really Benefit Local Species

It may sound counter-intuitive, but have a your forests be of diverse ages can do wonders for the local wildlife.

For example, the ruffed grouse is dependent on the existence of aspen trees. More than that, they thrive when they have access to aspen groves of differing age classes. As aspen grows so vigorously on recently cleared land that is the right habitat, logging has the opportunity to provide the young habitat the ruffed grouse needs. There are many other animals with similar relationships to diverse habitats, such as deer and turkey.

Great Opportunities for Foragers

There’s no other way to put it: recently logged land has the potential to be a forager’s paradise with time. From that first bumper crop of blackberries to the fruit and nut shrubs that can thrive with the increased light, a lot of good things can come from logged lands.

It’s even better when the logged lands are intermingled with mature forests in the area. This mixing of differently aged habitats produces a wonderful opportunity for plants and wildlife. For as much as it makes sense to love and appreciate a mature forest, not many things can thrive in a habitat that consists of miles and miles of a single tree species.

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.