Unmanned Aircraft Systems’ Remote Sensing Technology Used Against Bark Beetles in National Forests


Unmanned Aircraft Systems’ Remote Sensing Technology Used Against Bark Beetles in National Forests

Brett Whalin


This paper goes over the growing problem of bark beetles destroying North America’s forests. It first goes over the life of the beetles and the current methods of fighting them, in order to give the reader ideas on how they can be beat. It then goes over ways that remote sensing from UAS can help and how they would be implemented/mobilized. Later, other uses for the UAS platform are thought of. The last sections give both arguments for the implementation of UAS, and counter arguments. Both are summarized in list form and explained in paragraph form.


Our nation’s forests face blight on a scale rarely seen before. This is a pestilence that threatens to engulf our natural resources, laying them to waste. It not only is destroying the health of our forests, as well as their majestic look, but is ruining whole industries that rely on trees as a resource. It is raising the fire danger in these areas, taking homes away from animals, and makes thinning of the forests difficult with the debris of its passing due to fallen trees. This is the plague of the bark beetle and it is currently near unstoppable.

This paper will first go over what the bugs’ lives are like, how they are doing their damage, and the various effects of the bugs’ damages. The paper will then give a description of the various current methods for fighting beetles.

Figure 1: A Rocky Mountain Pine Beetle

While some remote telemetry is used, most of the finding of the beetles (the first step to defeating them) is mainly ground work, and therefore the paper will then propose a few new methods using unmanned aircraft systems (UAS) as a way to find the bugs. Finally, the paper will briefly cover other methods to help eradicate the bark beetles that are possible using UAS in a more direct approach than just finding the affected areas. It will also cover implementation and logistics of the operation from a Forest Service’s stand point. It will also point out the advantages and disadvantages of the UAS method over more traditional means.

The reason for going over the bark beetles life and physiology gives us an idea of how they live. This allows us to know how we might defeat them both by natural and man-devised means. It also allows us to see how current methods to kill the beetles are supposed to work and the mindset behind them. The section on current methodology of killing the beetles is meant to present ideas so that they can be understood when changed to fit unmanned aircraft systems. The later UAS sections combine the ideas learned in the first two main sections and present viable ideas/alternatives to fighting the bugs using UAS as a platform means to expedite the eradication of this infestation.

The Problem: The Bark Beetles:

There are 600 types of bark beetles in the continental United States and Canada. Two hundred of these species are in California alone.At least 10 new species have been found since 2002 in California (Reference 1).Most varieties attack conifer (evergreen) trees, though some varieties, such as the shorthole borer, attack leafy trees. Generally species have two generations a year, though some can have as much as six in one year.

Knowing the general life cycle of a beetle, while there are so many species and differences between each of them, is probably one of the most important tools to fight them. The general knowledge of the most common types has given us times of the year to fight them, general knowledge of how they work, and even insight into the fact that many colonies coordinate their attacks on particularly big trees.The mountain bark beetle, formerly known as the Black Hills beetle or the Rocky Mountain pine Beetle, is currently the most pervasive species, and one of the best to get a feeling of their yearly cycle (Reference 2).

The mountain pine beetle lays its eggs in late September. One female can lay up to 75 eggs at one time. They lay them in vertical tubes under the bark in the phloem layer of the tree (Reference 7). This is the area of the tree that actually produces sap and is where the beetles eat the most after boring in.

The eggs hatch about two weeks after they are laid. The larvae then burrow into the tree to survive the winter. Since the tree’s shelter alone cannot save the larvae from the winter cold, the larvae are able to produce glycerol from the parts of the tree that they eat, which acts as antifreeze (Reference 2). This makes them resilient to all but the coldest temperatures. Temperatures of -40 degrees Fahrenheit will kill an entire tree of beetles however if it lasts for more than twelve hours and if the colony is not very large to provide warmth for each other. Temperatures in that range for 24 hours or more are thought to be sufficient to kill off almost all the bugs in a tree for the larger colonies. If the temperature is above -40 degrees Fahrenheit, multiple days are needed. Temperatures of -30 degrees Fahrenheit must be sustained for five days to have a large effect on the larvae.

The larvae grow from 1/8th to 1/4th of an inch in length during this time (about five to seven millimeters long).The larvae state ends in late spring, where they then bide their time until July and August. These fully formed beetles then fly off to the surrounding trees. One tree of beetles usually infects two to three other trees around them. If winds are in their favor, more trees will be hit.

Other things to note are that hot summers tend to speed larva growth and also increase mating. The drier and hotter a summer, the more danger of an uncontainable spread is possible. The beetles tend to pick on the oldest or most weaken trees in an area, that way there is less chance the tree itself will stop them. Draught and heat aids in crippling the trees. Unfortunately, the beginning of this latest outbreak in the early 2000’s was aided by a several year drought in the Rockies and the Midwest (Reference 3). The dry trees also made it harder to see signs of the beetles, due to less sawdust coming out of the holes.
Temperatures inside the tree of 110 degrees Fahrenheit will kill the beetles, however trees are very well insulated, and this does not usually happen naturally. Lumber, however, is placed in clear plastic in the sun in order to kill off the beetles.

The tree’s mechanisms to fight the bugs are to release mass amounts of sap, drowning the parents, and killing the eggs with chemicals in the sap. This is also meant to push the beetles out. Trees also rely on woodpeckers and clerid beetles to kill off the pine beetles, though the populations of these predators are not in the forests favor in combating these “boring” beetles.A sign of a successful tree defense is larger, more scattered holes in the trees. Normally they are 1/4th to1/2 (six to thirteen millimeters) and inch wide (barkbeetles.org). On unsuccessful infestations, the holes are 3/4ths to 1 inch wide (19 to 25 millimeters). This is due to the tree pushing the beetles out with the sap, both making the hole larger, and making the more stubborn beetles desperate to make a bigger door into their “home”.

It is also made difficult due to the fact the females tend to purposefully go for healthier and bigger trees, while the males go for weaker trees at first. This is bad because not only are the weaker trees dealt with faster, but it means the males will likely fly to at least two trees instead of one, when the female releases a pheromone to call other bugs to them. However, the upside is the males might not finish off the hurt tree in time before they follow the female scent. This pheromone also tells the beetles the amount of other beetles in the tree. This gives them the opportunity to know there isn’t any more room left, or that they need help in subjugating the tree. It is thought that many colonies will work together and coordinate with each other through these pheromones (Reference 2). This pheromone also is the reason that their spread patterns of the two to three trees around the original are so predictable.

Their Effects:

The beetles’ way of attack makes it very hard to save the tree if the tree has not been able do to it itself. The beetles attack the lower parts of the tree, eating a ring under the bark so that no more water flows upward. This makes it so more of the tree is affected. Also, mature pine trees tend to have the bulk of their branches more than 15 feet above the ground, the beetles don’t have to contend with as much of the sap. The beetles also spread a blue fungus in the sap making portion of the tree in order to kill the tree’s only defense. The tree starves or is overheated because it can’t cool itself. The effects of such an effective attack that we cannot save the trees from have had several ramifications for fire danger, tourism, and animal habitation.

A recent aerial survey done by the United States Department of Agriculture (USDA) reveals the seriousness of the spread of the bark beetle (Reference 5). In Colorado and Wyoming alone, over 3.6 million acres of forest in the Rockies have been affected since initial tracking in 1996. The Black Hills has 400,000 acres of forest currently being infected by the beetles, out of 1.2 million total acres to the forest (journal). According to a Denver Post interview with a state forester done in 2008, Wyoming will lose 85- 90 percent of its lodgepole pine trees within three to five years of that article.

In those years, California, Colorado, and South Dakota have had some of their largest forest fires in fought-fire history.Examples of these larger fires are the Jasper Fire, the Battle Creek Fire, and the Elk Mountain Fire Complex (Reference 20). The Jasper fire covered 93,000 acres and was the Black Hills’ largest fire in recorded history. While many of these were initially caused by arson, the amount of dead trees due to beetle strikes definitely increased the spread of which the fires spread. This, exacerbated by the droughts of the early 2000’s made these fires very hard to fight. In the case of the Jasper fire, it burned hot enough to create its own thunderstorm.

Logging attempts to get rid of the dead trees are not keeping up. So far the Black Hills of South Dakota is the only forest starting to catch up with the problem in terms of spread. Other problems that these dead trees present are the threat of them falling on campers, blocking hiking paths/main roads, and obstructing water ways (Reference 5).

Dead trees also drop more pine needles, which kill grass due to their acidic nature. Also, lack of vegetation can lead to less soil stability.Colorado has a big concern that much of its sediment is being syphoned off into its mountain reservoirs, carrying away much needed nutrients for the new trees to grow back (Reference 6). With reduced capability to regrow its tree population to keep moisture in the hills, they predict fire dangers will stay unusually high for the next 15 – 20 years.

Aside from the obvious impact on the looks of the forest becoming less beautiful, the beetles have had many very grave impacts for tourism. As discussed, travel routes can become blocked, though usually these are dealt with fairly quickly. A major impact on tourism that is still connected to fire danger, directly due to the impact of the beetles, is the hazards at parks themselves. Jewel Cave National Monument selected 60 trees to kill on March 8, 2011, to control an outbreak near their area (Reference 11). This was first to reduce fire danger in the area, second to protect visitors from falling trees, and lastly to improve the image of the park. If the trees were not cut down then, they would most likely infect many trees in the summer due to the warm winter, meaning less bugs probably got killed.

Figure 2: Mount Rushmore last summer could not present its annual fireworks display due to pine beetles.

 An example of the beetles getting national headlines for both affecting tourism and fire danger was displayed at Mount, July 3, 2010 (Reference 12). The Shine of Democracy’s fireworks show has been the first 4th of July show each year for the nation since 1999. They have it on the 3rd of July to ensure that it is first. It has also been the biggest fireworks display in the nation since that same year. In 2009, Mount Rushmore’s fireworks pulled in 17,700 people, with 8,300 people inside the monument grounds at one time (Reference 13). In past years it has brought as many as 30,000 people to the mountain, just for that one day. 2010’s fireworks display was cancelled due to fear that the fireworks would start a fire because of beetle strikes on the back side of the mountain. This decision was made after the fireworks had been purchased.

While overall attendance for the 3rd of July did grow by 3,000 people throughout the day in 2010 compared to 2009, but the monument never got full enough, at any one point, to turn away people (Reference 12). Every year the mountain has had fireworks the park, its parking lot, and the hill leading up to the site has filled beyond capacity for the nighttime events and people have to sit at the bottom of the hill to watch the illuminations. This year, it looks as though that won’t be happening again. On September 13th, 2010 the head officials at Mount Rushmore decided to make the decision early to cancel 2011’s fireworks. They say that the surrounding forest has been too infected for them to beat the bugs in time. The forest, once the bugs are beat, would have to regrow as well. In other words, Mount Rushmore might have one less event for the 4th of July celebrations for quite a while to come.

Mount Rushmore is only one case, from one state. The beetles have affected tourism industries in Montana, Wyoming, and Colorado. California is also feeling the brunt, as the beetles have started an attack on the Redwood National Forest. Very few species actually attack redwoods themselves, but the other trees in the area are being affected. This area is a major part of the tourism for northern California, and southern Oregon.

Current Ways of Fighting:

While the bark beetles may be tenacious and we may be behind the curve at present, that doesn’t mean there isn’t ways to beat the beetles. The National Parks Department, the United States Forest Service, and many privately owned businesses have made fighting this infestation their top priority. Their current methods involve chemicals, logging, some remote sensing, and LOTS of ground work.

To kill the bugs, first you must find them. The most common method for finding beetle-struck trees is to actually walk to trees that are suspected to be stricken, look for tiny holes with sawdust coming out called “-outs”, and open up the bark with a hatchet to make sure they are bark beetles (Reference 2).  How they determine suspected area’s is through surveying, call-ins, or satellite imagery. All of these methods, however, find the trees that are usually already dead or nearly dead, due to highly visible signs, such as discolorations. Lack of chlorophyll is evident even in the visual spectrum, tending toward a brown or gray tint to the plant. Surveying methods currently get the most luck in catching some trees before they are dead, in order to stop the spread, but the survey is usually initialized through knowledge that already-dead trees are in the area.

Figure 3: Pitch-outs/Pitch-Tubes

Canada has put the most research into finding the trees on a more regular basis with remote sensing. While they still use satellites, which are expensive to launch and or reposition, they have been successful in finding semi-fresh strikes. They have also been very efficient (Reference 14) in mapping out the extent of bug-hit areas. They also artificially infected trees with the same fungus the beetles produce in order to get a baseline for how forgone a tree is.

The Canadian research determined that trees that are struck are also deficient in nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, iron, zinc, copper, and boron. The most important are the first five listed. Nitrogen will be the most noticeable missing nutrients from the trees. Lack of phosphorus begins necrosis in the tree. Lack of potassium dries the plant out. Almost all of these nutrients will change the color of the tree to show signs of stress. Also, the pigment in carotene in plants was shown to be the most responsive to the fungus. It was determined as the most sensitive to attack. These were all done in lab tests however and the report did not make it clear if they had tried to see lack of these elements using spectral analysis. However, these are fairly good/significant indicators and could be used in future indexes.

The Canadian research was primarily based off of shortwave infrared and near infrared telemetry. They used the water index (WI) R900/970, the Normalized Difference Water Index (NDWI) R860 – R1240, and the Simple Ratio Water Index (SRWI) R860. The WI and NDWI used the 1150 nm – 1240 nm range of the shortwave spectrum. They also used the 1500 nm – 1540 nm range of the near infrared spectrum. The SRWI was based on both visual spectrum indexes and infrared. These different indexes told them whether or not the plant was getting enough water. They also checked chlorophyll levels in plants using the 700 nm range of the spectrum.

The two systems the Canadian Forest Service used were the EO1 – Hyperion and AVIRIS cameras on various platforms. The Earth Observing 1 (EO1 – Hyperion) is a satellite that can detect over 200 different wavelengths, nine of which it can do simultaneously. AVIRIS is another sensor used both on planes cameras and satellites that is used for multispectral imaging.

Once found, the most effective means to defeating the beetles is thinning of forests. The nation’s forests have gotten far too dense to be healthy and allow other forms of vegetation to grow. Fires, that in the past cleansed the forests, are now suppressed to save houses and towns. This gives the added bonus to logging of not only making the forest healthier, but also generating money from timber sales. The problem that bark beetles present to logging is that it is consuming their good products, making the job more dangerous due to the amount of dead trees, and it is outpacing logging attempts to keep up to contain the threat. A large percentage of the trees that have been killed or infected by the beetles produce unusable timber. The timber that may be salvaged, although infected, takes time to treat/process before it can be utilized as a normal log. Also, the trees must be taken while they are still green and just hit, that way eggs cannot survive to infect other trees. By the time the tree shows visible signs of deprivation, it is too late to halt the spread.

The act of cutting down the tree alone is not only what the logging industry does to contain the bugs (Reference 2). The logs they cut down they then treat with chemicals to kill the bugs, or else cover them in plastic so they gain heat and toast the bugs. This is called “solar treatment”. Chipping logs works as well. It is also important to never pile infested trees near any trees that you think may still be good, due to spread of any remaining beetles. Burning of known infected logs is effective, but only when snow is on the ground so the fire does not spread.

There is also the alternative of planting trees that the bugs do not like to get them to move away. Redwoods, atlas cedars, and most leafy trees are not on the beetles’ dinner menu (Reference 1).  Otherwise, just keeping your existing trees healthy by properly watering the outer canopy is your best choice for prevention. If the trees can still fight back, the bugs are less likely to attack.

Chemicals have been used quite effectively but might not be worth the risk or expense. Some insecticides that are used are Verebone, Permethrin, Bifentrhin, and Carbaryl (Reference 7). Verebone is a behavioral changer. It acts like a pheromone in trees that are full of beetles, making other beetles think there is no more room left, and they move on. It is quite affective against low populations, but not in wider populations. The upside is it does not affect other animal life but it does not actually kill the beetles. The others affect humans, birds, and or fish with varying degrees. Almost all affect fish populations. Carbaryl is also recognized as a carcinogen to humans. Permethrin is metabolized by birds and mammals; however aquatic life is highly susceptible to it. It also kills off many other beneficial types of bug life in the area. This means the beetles would have less natural enemies as well. However, out of the three killing pesticides mentioned, it seems to be the most effective and least deadly to non-targeted living animals. The problem with these four particular chemicals is that they are all made by few companies (Verebone is only made by three companies). They are also better used on small scales such as campsites.

The United States Forest Service currently is trying a bio-pesticide called Chitosan. This particular chemical is meant to help the tree itself. It makes the tree produce up to 40% more sap to help defend itself. According to the article on Wikipedia, it achieved a success rate of killing 37% of the eggs in the test trees and is supported by the environmental protection agency (EPA). It is produced by AgriHouse Company. Other chemicals like this that help the tree, or only specifically kill bark beetles are made, or in development, but cost several million dollars to implement on a forest size scale. One company that that does this spraying when someone can afford it is Tiger Tree Land Management (Reference 20). These methods have been tried at Shoshone National Forest and the University of Wyoming.

UAS Remote Sensing To the Rescue:

UAS remote sensing could possible turn the tide in a large way in defeating the bugs. While UAS and their sensors do cost enormous sums of money, they are easily deployable, cheaper than hiring manned planes in the long run, and far more versatile than satellites. They can expedite the actual finding of the trees through various methods, as well as the planning of the logging operations through mapping.

As demonstrated above in the Canadians’ remote sensing experiments, infrared technology makes finding of stressed trees very easy. Using this knowledge, as well as knowledge gained from farming that uses these methods to see crop health, we can set up surveys of forest, sector by sector, to find bug-hits. We can also find trees that might be stressed from natural causes to take them out before the beetles get to them. This surveying method will give us much closer imagery and finer detail than satellites. It will be easier to see the extent of the damage and make better decisions. Also, since the UAS are mobile, their versatility will be very useful over satellites. They can scan an area for as long as they want, whenever the Forest Service needs, in almost any weather. Satellites on the other hand are hard and expensive to change trajectory to look at specific places. They also have a limited window of opportunity to take pictures of their target before their orbit takes them out of range (remote sensing book).

Another use of remote sensing could possible provide an actual way to save the trees. When doing a survey of a known beetle infested sector, the survey crew could launch a small UAS, such as DraganFlyer, with a thermal camera to see where the bugs are specifically in the tree. First of all, this confirms that they are beetles. Second of all, the survey crew could then come to the tree, take off the bark with a hatchet, and then lightly spray the exposed area with liquid nitrogen. While the instant freeze may damage that part of the tree, or even kill it if used to liberally, it will certainly kill the bugs. If this is done before the bugs have spread their fungus too far in the tree, the tree may be saved. As of present, we have NO means of saving trees once the bugs are inside.

Small, rotary UAS such as DraganFlyer also can make the actual surveys go faster and safer. While battery life would be a limiting factor, the DraganFlyer or similar craft could fly through the trees with relative ease, avoiding all of the terrain which would make it possible dangerous for a survey timber crew to traverse. They can move relatively quickly, don’t need breaks due to tiredness, and can hover to get just as close to the trees as a human might, for inspection.

Even with UAS that can fly in-between the trees, a ground crew is going to have to come in and cut down the dead lumber. Timber sales take a lot of planning and involve spraying paint on trees. While having a UAS spray X’s on trees might be impractical, they can still lend a hand in the planning. Larger UAS such as Shadow and ScanEagle, both far more prevalent craft in the government that small UAS, have sensors such as side long radar (SLAR) and synthetic aperture radar (SAR). These systems scan the ground with radio waves to create a very precise image. They have been used in creating maps for decades. Not only will you be able to pick out trees from the images to cut, but you can also see dead trees and underbrush that may be dangerous to walk through. This will allow you to plan and map around these problematic areas.

Figure 4: A ScanEagle UAS could help find the bark beetles.

Other remote sensing techniques could be pheromone sniffers used to find the bugs pheromones. This technology is already in place and used on UAS to inspect power plants (References 16 & 17). They can find certain chemicals fairly well using chemical sniffers. Since the Canadian experiment also told us what elements we need to look for a lack of, we can use these chemical sniffers check for that as well.


Implementation of this endeavor is what will be tricky. UAS are heavily restricted due to the lack of any actually regulation on them from the Federal Aviation Administration (FAA). The FAA requires all UAS to fly in Certificates of Authorization and Waiver (COA) areas. These are difficult to get, since they basically are waving away certain FAR’s agreed upon by the FAA to get a job done. Only publicly owned entities, such as government agencies and state schools, can get a COA. The appeals process to make one is also very long and arduous.

Equipment also presents a problem. Which UAS are best for the job? What sensors can a group use to get the job done correctly, but also cost effectively? Where will these supplies come from?

To answer the question on airspace and regulatory problems, the solution is actually rather simple. The Forest Service currently has the most knowledge on the bark beetles, is currently the most affective unit for managing contracted timber sales to defeat them, and also happens to be part of the United States Department of Agriculture. It would be relatively easy for them to set up a COA, due to the fact they have to do this quite often on fires. Also, they liaise a lot with the border patrol, which own very many; very good UAS.

While the Forest Service is one of the more poorly funded government agencies, they still have plenty of resources to pull upon. They can also make deals with UAS manufacturers directly. Borrowing sensors from other agencies for other favors could be done as well. This is already done with many of their land vehicles such as the vehicles they rent from the GSA (Reference 20). In the end, they will still have to buy much of this equipment for themselves, but since they are provided for by the government, it will not be so much a problem in the long run.

Another aspect to the buying of equipment is that it doesn’t have to be expensive. Both the University of Southern Queensland and the University of Cordoba have done remote sensing of crops using UAS as a platform (References 23 & 24). They used commercial off-the-shelf technology (COTS) and still produced relatively good telemetry. Examples of relatively cheap infrared technology would be the MCA-6 Tetracam sensor and the Thermovision 140M. Both of these were used by the Cordoba study. The two UAS they used were also COTS and built by their study program.

The Forest Service already has experience in these technologies due to their management of the forest, though it will mean they have to shift resources from those divisions. Their satellites have been creating the indexes that many UAS farming fields use to base their work on. While the sensors indexes may have to be adjusted for being in atmosphere, those same indexes, such as the Normalized Difference vegetation Index (NDVI), the Crown Leaf Area Index (CLAI), and the Forest Light Interaction Model (FLIGHT), can be used in this application (References 23 & 24). Indexes may also be able to be made in relation to the lack of certain nutrients in the plants, due to beetles, that both remote sensing pictures and chemical sniffers may be able to detect.

Other UAS Uses to Combat the Bug:

UAS have many other applications towards defeating the beetles other than just remote sensing. Spraying of pesticides is already done by UAS in the agricultural field. Also, new experimental uses of UAS are using sounds waves to control bug-migration patterns.

Pesticide distribution is an option that has already been used for years against other bugs and farm crops. They have dropped both nutrients for the crops to grow stronger and poisons that target the bugs. Japan has used the RMAX UAS helicopter to great effect in this field, due to its high capacity for carrying loads (Reference 21). The RMAX can carry load of 65 pounds and fertilize up to 5.5 NM of crop

Figure 5: RMAX spraying a field in Japan.

While pesticides do have a habit of killing other animals, scientists have been successful in targeting only certain things in the past. When the Great Lakes were having a problem with the foreign-introduced lamprey killing all of its other fish in the 1970’s, they developed a chemical that destroyed the fish’s ability to procreate. While this method took a while to take effect, it did solve the problem of the artificially introduced fish (Reference 20). Later, the native fish were reintroduced.

Another option that UAS might be able to provide is acoustic-herding of the bugs. The military is presently experimenting with this technique to “herd” locusts towards enemy targets as a natural weapon (Reference 15). The UAS use acoustic frequencies specifically meant for that particular bug and transmit it towards the ground. Other UAS behind the main group make sure the bugs do not fly in the other direction from the target.

While this is still only a theory and is under development, the idea is sound. Similar devices have provided over 33% effectiveness in areas of 5,000 square feet for pest control (Reference 15). While this won’t get rid of the beetle problem permanently, it might keep them on the move long enough for foresters to clear trees and implement other methods. Acoustic technology also is relatively cheap and does work on other animals other than bugs.

Advantages of using UAS:

UAS provide us with a unique opportunity. Not only can they cover wide areas, in all kinds of weather. They can work at night and are virtually undetectable once they are more than 1,000 ft. – 3,000 ft. up. All of these will make it so animals won’t be disturbed. They are also easily recoverable and relatively cheap compared to a satellite or chartering a pilot. Most can also stay on station for many hours at a time, while the crew can be switched out with ease for rest periods. Their low fuel usage, sometimes none at all, in the case of electric UAS, is also a benefit to the environment.

Other advantages are some, such as the RMAX, can carry large loads for missions such as spraying. Still other UAS can carry a wide away of sensor packages all at once. Some satellites would have to do multiple passes to get the different imagery. The UAS can also be directed more specifically to a target than a satellite and even in places that manned planes will not go.

The sums of the advantages are:

Significantly cheaper than satellites or most manned planes

Low environmental footprint

Long “on-target” durations

Instant feedback

Flexibility of location 

Flexibility of mission load out with one platform.

Disadvantages to using UAS:

The disadvantages to UAS don’t really come from them themselves usually, but the legal and financial roadblocks that they are fettered with. This paper’s ideas were expressed from the point of the United States Forest Service making a special division to tackle the bark beetles using UAS and survey teams. This is because they can more easily get the equipment once congress gives them a budget and because they are a public/government entity. This means that they can easily get a Certificate of Authorization. Civilian groups however would not be able to join in because they cannot get a Certificate of Authorization. They might contract with a government agency but this still limits the scope from which the Forest Service can draw upon for allies in this battle.

Also, while cameras were presented from commercial-off-the-shelf point of view, the most effective tools will be the higher grade equipment and sensors the Forest Service/other government agencies can get from liaising with other each other. There are very few good SARs that are cheap. NASA is the past has teamed up with the Forest Services, as well as the USDA’s other agencies. Border Protection has done some work for the Forest Service, and vice versa in the past. Civilian groups won’t be able to draw upon as much of a base. Also, even if the Forest Service gets some of the stuff on loan from other agencies, they WILL have to buy a lot of it for themselves. High quality synthetic aperture radar and its image processing take quite a lot of funding. Also, the smallest of UAS mentioned in the article, DraganFlyer, is $36,000 for the entire kit (Reference 18). ScanEagle at minimum price for the bird alone is $150,000 (Reference 19). Raven UAS is about the same price and larger models such as Predator or Shadow will cost in the millions, if you are able to buy them at all due to the military’s need.

Also, UAS is not a well-known field as of yet. Very few pilots exist outside of the military and the companies that make the hardware. Training takes time and resources as well. Adapting pilots to the unique challenges of UAS is still an emerging issue, though one that isn’t presently too many problems.

The sums of the disadvantages are:

Expensive upfront costs of both the plane and the sensors

Civilians are not able to help on a wide extent

The Forest Service already has satellites with SAR on them doing a more restricted, but basically same job

Very restrictive regulations

Spraying is uneven from above

Training of UAS pilots is scarce outside the military

Image analysts from satellite  imagery need to be moved to this new vocation

Still and emerging field.

The Future:

The future battle against the beetles has its low and high points. Montana and Wyoming may see an improvement as the beetles have nearly eaten themselves out of viable trees (Reference 8). In 2010, Wyoming lost 314,000 acres to the beetles, but that was still only one fourth of what they had lost in either 2009 or 2008. Some forests in Wyoming the bugs have not even been able to get to since they had killed the viable trees in 1988 and 1995. The Big Horn Mountains and Yellowstone National park are two of these areas. Also, a harsh winter has helped in places such as the Grand Tetons (Reference 8).

While those two states may see an improvement, there are still many other problems looming to be dealt with. The Forest Service’s budget has been severely cut over the years (Reference 9). Recently, Congressional representatives from South Dakota, Wyoming, Colorado, and Nebraska have brought this to the floor as a “national emergency” and “epidemic”. While $40 million new dollars was given to the Rocky Mountain Region, only $2 million went to a forest outside of Colorado, which was the Black Hills of SD. The Forest Service already has set aside $49 million of its own budget to combat this threat, but they need more.

Another problem is that while thinning trees makes forests healthier, environmentalist groups such as the Sierra Club are opposing all logging action with everything they can. They have spent $37 million dollars to combat cases specifically in logging in beetle thinning projects (Reference 10). With the combination of 15 different environmental groups, over 1,200 cases have been filed just to slow the Forest Service down, if not stop operations in their tracks. Tactics like this have already done their damage. In the 1990’s, Beaver Park’s forest was destroyed by the beetles because environmental groups did not want any thinning to be done in the area. By the time the Forest Service came to an agreement, far more trees were lost than would have ever been cut down in the original plan.


While the UAS platform is a new technology and faces many challenges, the US forests need a new weapon to face this epidemic. While many of the methods proposed here were highly speculative, they do have a chance to work, and should at least be tested. While funding and getting enough human resources on the UAS teams will be a problem, UAS have proven to be versatile enough in other fields to have revolutionized that industry. Hopefully some group will propose a large enough test in this field that it will be able to show all the potential that UAS have to offer.


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Brett Whalin

US Commercial Multi-engine; Instrument Airplane pilot UAS/RPV/RPA/UAV pilot Sensor Operator