Forestry, Services

The Cost of Brush Mulching

Most would define the question of, “how much does it cost to mulch some brush”, as impossible to narrow down. However, over the years we have mulched our share of brush, so we are going to give it a whirl. For this article, we are going to focus on the small rural landowner type of mulching. If you are someone who has land covered in brush and you are looking to open it up, we hope by the end of this article you will be better informed about brush mulching.

Now to start- what are the variables that go into mulching? The five factors that are probably the biggest are density, environment type, species, finish quality, and terrain. As it turns out it is pretty hard to define those very well when comparing one property to another. We have found that the old adage “one man’s junk is another man’s treasure” is equally true as “one man’s thick brush is another man’s field”. For this reason, we almost always do a site visit before we offer an estimate. We do not want to overestimate and scare a potential client with a high price or give such a low price that we set false expectations.

Now with all that said, let’s try to break it down by each factor.


Can you walk through it? Is it over your head? Are there a lot of small stems or are there fewer big stems? When we are talking density what we really care about is how much volume of material is there per acre. It is really hard to quantify and thus takes a trained eye to get a close approximation. For example, try walking through a thick patch of scotch broom (an arch-nemesis of western Oregonians). It would seem pretty thick. It really isn’t all that dense though, it is nearly impossible to walk through it, same with a wall of Himalayan blackberry.

Now imagine a mass of wild cherry, cascara, vine maple, and wild hazelnut all intertwined with Himalayan blackberry. That’s dense! You have the base layer of blackberry then the stems of everything else that stretches to the heavens with numerous branches to about twenty-five feet in the air. We see this type of density all the time. For us, it is often fun and the most rewarding because of the huge difference we see at the end.

For sake of simplicity, we will say the above examples are on even terrain with nice soil and the project is only big enough to bring in a smaller machine like a Cat 299d3 XHP. To mulch the scotch broom is probably around $400 – $700 per acre. The thick Himalayan blackberries will be about $400 – $700 per acre. Mulching the big mess of everything from blackberries to small trees will range anywhere from $800.00 – $1,300.00 per acre. This is all to a moderate finish level.

Environment Type

When I talk about the environment type, I mean is it an open pasture? Is it a stand of young timber that has never been thinned? Is it a large mature forest with big spacing between the trees? Is there large downed material everywhere on the ground, or stumps hidden in the brush that an operator will have a hard time seeing? These factors all play a huge part in the price of mowing down a few twigs.

As an example, if we are fairly positive that an area was just a pasture or open ground before being covered with brush, we can go charging in with some assurance that we won’t slam into a stump. Can we slam into a stump and live to tell about it? Usually yes, but it is hard on equipment. There is only one guarantee with machines-they will break, so we try not to hit things too hard. It can also be hard on the operator, even at 1-2 mph, a sudden stop can be quite jarring. When we walk the project we look for clues and ask a lot of questions about what is known regarding the state of the ground under the brush. We also pull historical satellite imagery and sometimes do a drone survey.

If the project is what we call “under brushing”, which is mulching all the brush under the canopy of an existing stand of timber; then we have to duck and dodge as we work. Since a lot of our time is spent going in reverse, and we hate scarring up retained trees we have to work slower. Even in our forward passes, we won’t be able to work in a grid as we might in an open environment.

During the walk-through, you will probably notice the project manager has an infatuation with rocks. It’s not because we are in love with it, quite the opposite. It makes everyone’s day worse. At the minimum, a small rock increases the wear on the machinery’s teeth. At the most, a big rock is hard on everything- tracks, carbide teeth, knives, operators, etc. Yes, we can do it, and yes a good carbide tooth can take a hit. However, carbides do break, are expensive, and worse is that we will have to run carbides on the full rotor if there is a lot of rock. We try to run knives in the center of our drum most of the time. They make a huge difference in production, but if there is a high percentage of rock it simply isn’t worth it.

Do we still want to look at your projects with rocks? Yes, it just makes a frustrating impact on the price of mulching.

Environments like working a brush patch in an old clear cut, or under brushing in a thick stand of timber versus a wide-open known area can impact the price anywhere from around 25-50%. Rock can be even worse and in some instances, calls for a different configuration of machine like a swing machine.

Oddly enough the higher the density, the lower the effect on the environment because the density of the material keeps us moving at a slower pace. In the wintertime, there is less leaf load. Leaves or the lack thereof allow an operator to see the obstructions that are coming up, it can make a 5% difference in productivity on some sites.


Species make a bigger difference than most would think. To be honest, I still get surprised by it sometimes. What it boils down to is: how strong and how pliable is the wood fiber. The reason this makes a difference is that ultimately what a mulcher does is breaks wood fibers apart from each other and shortens them. Vegetation is a bunch of elongated fibers bound together in different orientations.

Some species like cherry and oak have incredibly strong fibers, which are bound very tightly to each other. Others like pine and hawthorn are very weak. About the easiest way to determine how something will mulch up is to try to break it. Whenever I encounter something new I try to snap a limb. If it just keeps bending it will probably be difficult to get a nice breakdown. If it snaps, but not all the way, and keeps fraying out, it will probably be moderately difficult. If it completely snaps in two pieces easily, you know you’re going to have a fun day of mulching since those kinds of wood shatter fast and progress to a fine finish pretty easily. If you can tie it in a knot and swing through the forest on it, well, you’re in for some chewing. The best way to mitigate this is to up the game by running knives and or a higher top speed. Often times after someone has mulched with dull carbides in this type of material, you will see frayed stumps sticking up everywhere like upside-down brooms. This is because of a lack of edge on the tool being used. If a person doesn’t care much about how it looks then this may not be an issue, it just takes a little extra time and being particular about the method.

The most stubborn you will come across in the Northwest is the Viney Maple. The easiest is something like ponderosa pine. Himalayan blackberry, although very pliable is not very strong and scotch-broom is really brittle. The mixture of trees, bushes, and vines like we mentioned, make up the catch-all term “brush”. The difference in species can generally account for about 30-40% discrepancy in the price of mulching.

Finish Quality

The finish is a function of time when it comes down to it. Another way to put it would be passes over the material. As I’ve outlined in this article,

“Why is he going backwards all the time? A technical look at the material breakdown”

each time the mulcher goes back over the material it is drawing it up through the housing and reducing it more and more. The higher the number of passes, the finer it will become. Some materials with more brittle characteristics won’t take many passes at all; some may take 3-4

A really rough pass can be done with a forward pass as a Sunday drive through the woods. It won’t look very good, but it might do the job. This is sometimes requested for a simple reforestation job, where the only goal is to kill material and get it down to where a person can walk through, plant a tree, and treat it with spray.

Finish level varies from super rough like I outlined above, to extremely fine and beautiful, which is often referred to as a “Park Out”. In other words, we are going to make that mess of brush look like a park you will want to play frisbee on. In fact, we did a frisbee golf course not long ago. Most sites can be made to look like a park, it just takes time, energy, and an operator with some finesse.

The time it takes to blow out the ground to a really rough finish versus a fine park-like finish can be double. Yes, a 200% increase. It just depends on what you want.


Last but not least, is the terrain. The terrain or topography is one of the only things that can really make a person say, “This can’t be done”. Let me be clear, the way I look at things is that anything can be done. But is it really feasible and worth the cost? We can do some crazy stuff with a helicopter and a rock climber, but there would have to be an extremely good reason.

The most difficult type of terrain we run into is when it is really steep. Luckily, we can usually work on steeper ground than most people think. It might require using a different machine though. A typical forestry skid steer with rubber tracks on it can hang onto a 45-degree slope in optimal conditions. We rarely see optimal conditions though. The factor that we look for when assessing a site is how stable is the soil. A lot of time hillsides have very soft crumbly soil, which can limit the machine. The biggest factor is how wet is it. It doesn’t take much rain to make the soil surface slippery.

When we aren’t sure if we can handle a hillside or not the tipping point for us is if we have an escape route or not. Most operators prefer to work from the bottom of a hill toward the top, that way if it gets too steep gravity is helping you get back onto already worked ground, instead of pulling you into unknown areas. As we work, the layer of mulch on the ground can increase the traction of the machine as well.

It may be that we just have to schedule the job for when it is dryer or bring in one of our specialized steep slope machines.

The other most common terrain challenge is soft ground. Most of the tracked mulchers you will see are somewhere between 4.5 – 8 psi. When all my weight is on one foot I’m putting about 6 psi on the ground. So I usually figure if I can walk on it then I can probably mulch on it. What will compound this though is how many passes we will have to make. The soil compresses and expands every time pressure is applied and removed. This compression and expansion in wet soil are what makes mud. The other factor on PSI is how it is distributed. A set of tracks that can move independently of each other, like some of our machines means that pressure is spread more evenly over the uneven surface of the soil.

Again wet soil may mean that we just have to use a different specialized machine. This may ultimately mean the difference between being able to do the project or not. Much of the time wet ground is associated with Riparian areas or wetlands that may be illegal to work in. However mulching is often used to restore this type of ground, so it is a case-by-case basis.


I hope this has given you some idea of what to expect, and what we are looking for when we do a site visit. As I said above, this was tailored to a typical small rural landowner, but it also gives you a glimpse of all the factors in any project. It is very difficult to narrow down the price, but I hope I have helped give you a general ballpark of the project cost.

To consolidate this all, we rarely see projects of this nature below the $400.00 per acre mark and rarely over the $1,800.00 per acre mark.

Ultimately the three biggest factors in completing a job at the expected price point are:

1. A project manager that takes the time to understand the client’s needs, the challenges of the project, and the ability of the individual machinery.

2.An operator that understands the goals, how to manipulate the machine, and most importantly cares about providing the best job they can for the customer.

3.The right machine for the job is outfitted with the correct hardware for that specific project.