Dual path Mounder

Canfor is an integrated forest products company based in British Columbia. They have various woodlands operations and manufacturing facilities in Canada and the United States.

The Mounder project was primarily driven by the efforts of Mr. Tim Vinge (of their former Hines Creek operations). In the early 1990's, Tim was responsible for silviculture (cultivating trees) activities in the Hines Creek, Alberta areas. His focus was the reforestation of spruce trees. While reforestation is widely accepted as an ecological friendly activity, the truth is that the survival of human planted spruce trees is not very high in a variety of conditions.

Tim had researched and experimented with a number of ground preparation techniques. Some, like furrow plowing, were to intrusive to the land, others worked on other continents but did not produce positive results in the Canadian boreal forest condidtions. The technique he found the most effective was mounding.

A Technical Perspective of a Mound...

The technical details of mounding is something I would be better to leave to experts to describe but people always want to know what a mound is, why it is important and what the purpose of this machine is.

A mound is... well... it's a mound! Imagine a large shovel (like on a construction excavating machine) that digs down into the ground about two feet and flips it's contents, upside down, on the ground in front of where it is digging. Theoretically, it looks something like this image:

The organic layer, or humus, is basically the dead vegetation that accumulates on the surface of the ground while the forest is growing. Depending on how old the forest is and the conditions during the forest's life, the humus can be anything from a few inches to more than 2 feet in thickness. In reality, mounds look more like this:

The Advantages a Mound gives Spruce Trees...

To reiterate my disclaimer and plead my ignorance in advance: I am certainly not an expert but I was exposed to some of the theories about the benefits of mounds and problems with standard reforestation and I will regurgitate what I remember here.

In the past reforestation was not scientific. To minimize costs, seedlings were simply planted in the ground at more or less random intervals and left to grow. Survival rates were terrible, in the order of 5-10% - something that I think few people know about. By studying how Alberta's boreal forest recovers from fire, Tim and other researchers found that spruce does not come back immediately. Instead, aspen is usually the first to comeback. As the aspen stands age and die, spruce trees begin to grow in the fallen carcass's.

What the researchers found is that it is very important for spruce trees to set their early roots in vegetation, not soil. The humus in a mound is man's way of short cutting the process of growing and falling aspen stands. Creating a double layer of humus is very important in areas where the humus layer is thin. The other thing about the humus layer is that it naturally composts. Thus, it breaks down and disappears over time. The double layer helps ensure that it remains for the early years of the spruce tree's life.

The composting of the humus generates heat. Researchers speculate that this heat elevates the root's temperature, which is beneficial to tree growth. As a side note about how significant this heat is: during a winter service call to the Mounder I found it interesting that if I overturned the snow, the humus layer was very warm to the touch and actually steamed. That year there was an early, heavy snow fall and the snow acted as insulation. The warmth of the humus composting prevented frost from forming even in January.

There are other characteristics of the mound that aid tree growth. Another little know fact (or at least it surprises a lot of people that I have talked to), is that the land can flood and become a swamp when the forest is clear cut. The trees consume enough water that, in certain areas, they control the water table level. When they suddenly disapear, the water rises and can literally cover the landscape. In areas that get swampy, the mound elevates the seedlings and helps keep their roots dry. The elevated mound also warms under sunlight better than the swampy areas around it, again helping to warm the roots.

In dry areas, where lack of water is a problem, the hole behind the mound helps collect rain water near the tree. Moisture tends to wick through the humus, to the tree.

One final benefit of the mound is in the clay cap. The clay helps prevent grasses and weeds from growing right adjacent to the tree and helps the seedling compete for sunlight. When a forest is clear cut (or burns down), seeds that have accumulated for years suddenly come to life. All types of grass, some growing as high as 5 to 6 feet in a season, awaken when the sun and rain suddenly blanket the forest floor. These grasses can easliy choke out the small seedlings that take years to get to 5 feet.

Pictured to the right is a seedling that was planted in an experimantal mound and has done well. I believe this tree was planted 5 years before the picture was taken. Note how tall the grass and weeds are.

I do not have access to Tim's test data, but I do know that mounding greatly improved the survival rate of spruce trees. For experiments and early production, Tim used excavators with specially designed shovels for making mounds. It was a time consuming job and the monotony made it difficult for the operator to stay focussed and maintain quality. Tim came up with the concept for the mounder to address these needs.

Along Came a Big Mounder...

Tim had assessed other mounding machines but found they were not what he was looking for. For instance, there was a mounder from overseas that produced mounds that are small compared the mounds Tim was making with the excavator. In it's homeland, the mounds were fine but Canadian winters are harsh enough that the mounds would disappear in one season.

As Tim began to develop this machine, he assembled a team including Carl Zanon (previously of the Alberta Research Council) as project manager, Allen Pusch of Machine & Product Design for the mechanical/structural work and us at Qsine to do the hydraulic power system and electronic controls. Don Johanson at Klockner Moeller did the original PLC control. Later when the hydraulic speeds were increased beyond the input cabability of the PLC and winter operation required temperatures lower than the PLC could handle, a microcontroller was installed.

Qsine's Part...

Qsine designed, manufactured and installed the hydraulic and electronic power and control systems. The prime mover is a 135 hp Perkins (Caterpillar) engine driving a tandem (hence Dual Path) Volvo open loop, load sensing pump. The hydraulic cylinders are custom designed by Qsine for the application. Hydraulic control is performed via two Danfoss proportional valves under the command of two servo, motion control, digital signal processors (DSP's) that are sub-servant to a Motorola HC11 microcontroller. The control can detect obstacles in the path of the scoops (via pressure sensors) and can abort the process when necessary.

This project nicely illustrates Qsine's ability to bring together hydraulics, electronics and machine elements in both design and manufacturing to provide a practical, real world solution for a complex problem.

In operation it creates mounds approximately 18" high, 2-3 ft wide and 4-6 ft long and produces 1000-1200 mounds per hectare. The straight, dual rows of mounds makes it simple for planters to keep the tree spacing even. On flat land, with open areas, the Mounder can produce at rates up to 8 times faster than a backhoe. In high sloped hills or in confined areas, the excavator is still the machine of choice.

If We Only Knew Then...

We had a lot of respect for how difficult this project would be going into it. And at this point we are even humbler than when we started.

From tip forces on the scoops entering the ground being double what we measured on test plots to changing the machine from summer operations to winter operations, we saw unexpected conditions arise that threw our assumtions out the window. We prepared the machine for harsh service but in watching the machine operate over the years, we have been continually amazed at how rugged the work environment is for this machine: from shearing off 3 inch steel pins to rolling the machine over in rough terrain, there have been a lot of lessons about expecting the unexpected.

Other than saying Tim is a very dedicated and sincere person, I am not sure how else to describe him and his approach to this project. When this project first showed up at Qsine, I wondered how serious this fellow was about growing trees. I have been skeptical about forestry companies and the enviromental propaganda that comes out of them.

As we worked on this project, Tim gained my trust and respect. He really was serious about finding better ways to grow trees. Participating in this project showed me that there are a lot of people who are dedicated to sustainability of the forests. However, we also came across a number of those people who are not; they know how to recite their dissertations but they really don't care never mind putting their money where their mouth is. This is unfortunate as it shrouds the good people in a cloak of suspicion - to which I was guilty of.

To this day the Mounder alternates back and forth between being trapped and being propelled by politics, opinions and new ideas. Typical to an idea ahead of it's time, it generates both excitement and fear as people look and speculate at (and often exagerate about) what it is capable of and what it may change. Even though well over a million trees have been planted behind this machine, and it has proven itself to be an economical way to produce mounds, it is a new concept that is not quite understood. As a result, it currently sits in limbo waiting for people to make decisions as to whether or not they are going to use it. And whether they will use it for it's indended purpose or other applications that they think it could be used for.