Summary of Arundo Control Methods

WHAT TO DO WITH ARUNDO BIOMASS:

One of the issues with Arundo control is what to do with the dead Arundo biomass. In some cases it can be left on site to decompose naturally over time. This is a benefit because the cost of removing the Arundo stems and disposing of them can be very high. The more Arundo material is handled and transported the higher the cost. However, in some situations presence of dead Arundo biomass is a concern due to potential flood or fire hazard, aesthetics, or the biomass may need to be removed for native re-planting. The main options for dealing with the Arundo stems that we are aware of are: 1) chipping, and 2) mowing.

CHIPPING:

Conventional chippers often do not work very well in chipping Arundo. The fibrous nature of the Arundo stems is very hard on the machinery, and the Arundo is not chipped into small enough pieces. In addition operators have difficulty feeding material into the machine and it can be dangerous because a lot of force is exerted trying to push the cane into the chipper.

We have had success using a high powered (at least 80hp, we used 100hp) drum chipper. This has worked very well, even on green cane. Material is finely chipped and the machine feeds itself, creating a much safer environment for workers and chipping at a faster rate than 'regular' chippers. Although high powered drum chippers are more expensive to rent than 'regular' chippers, crews can work faster. The green Arundo stems are chipped so fine that there is almost no resprouting. However, a very small amount of resprouting can occur from larger pieces of stem that make it through the machine and remain moist. If they chipped material is spread out it dries very quickly. Drum chipped material is similar to straw and could be used for similar purposes.

These chippers may be hard to find to rent. Vermeer makes them for sure and other companies may as well. Regular chippers, especially low-powered ones, do not work that well with green Arundo stems - they might do okay with dry Arundo stems. If you have a big stand and a lot of biomass it is cheaper getting the better machine because you can chip much more material to a finer mulch and with greater safety. These high-powered drum chippers run from about $300 per day (may be more depending on if you are having it delivered rather than picking it up).

Images of a drum chipper in action, and chipped green Arundo produced

MOWING:

Mowing is carried out in place suing a hammer-flail mowing attachment that is mounted on the front of a rubber-tired tractor. Alternatively slope mowers, hydroax, and other mowing devices can be used (not all are rubber tired). Generally all these devices work very well on relatively flat even terrain. Somenewer machines are articulated, allowing them to maneuver over more difficult terrain. Some mowing devices have also been attached to a mechanical arm, allowing them to mow banks. Our experience has been using a hammer-flail mowing device.

Mowing is generally best suited to dense Arundo stands. However, if the stands are very old it may be hard to maneuver through them and there may be hidden obstacles (i.e. old junk) or unexpected drops. Native vegetatin can be avoided as long as it is not too intermixed with the Arundo. Arundo that is growing very closely with native can be cut by hand. Mowing green stands of Arundo tends to produce coarser fragments of cane, particlay if the stand is very dense and old. Mowing dead cane is much easier and produces finely mulched material. The operator can move back and forth over an area to mulch the material finer. 

Mowing is advantageous because no Arundo material has to be moved by hand or moved off-site. The limitations to mowing include site access, terrain, amount of native vegetation, and noise issues. Some sites may need to be 'prepped' to facilitate mowing. Costs for mowing are generally quite low ($1,500-$2,500 per acre, 2 acre minimum), especially compared to hand removal and chipping ($9,000 -$15,000 per acre: extremely variable due to site access and proximity to chipper).

If the Arundo biomass has to be removed, our preferred method is to foliar spray the Arundo and allow it to die, and then to mow the dead cane. 

We don't yet have cost figures for using a hammer flail mower - but this could be an issue. The usefulness of this machine may also depend on site conditions - how thick is the Arundo? Is the terrain uneven? Are there hidden hazards (old metal debris within the Arundo)?  This seems to be a potentially useful method for higher shelf Arundo infestations that are in relatively flat areas away from the main waterway. As far as we know the main group that has this machine is Pestmaster Services (http://www.pestmaster.com/arundo.htm).

Images of a hammer flail mower in action