Controls of Invasive Plants

By Thembi Borras

Preventing the spread of invasive plants is easier said than done given the vast expanses of invasive plants with which we are faced. Harding grass, which grows much taller than the native grasses it replaced increases the fire danger in many of the steep grasslands in Rancho Navarro where I live. Each year I notice more and more brooms and star thistle along our roadways. According to an article recently published in the May 2006 issue of the Mendocino County Farm Bureau's publication medusa head and barbed goat grass have become increasingly problematic to wildlife and livestock by reducing native populations of desirable feed and giant reed, also known as Arundo, and Himalayan blackberry have been charged with clogging local waterways.

Faced with a small backyard population of invasive plants well timed manual control can be effective. However, addressing large populations is a challenge because treatments may require long term commitments from stakeholders, can be expensive and can in themselves adversely impact the environment. The trick is for land managers to decide which control method is most effective, while being the least damaging to the ecosystem. Controls being used include public education, manual and mechanical, grazing, prescribed fire, biocontrol, herbicides and Integrated Pest Management (IPM) which incorporates a combination of these controls.

Manual techniques which include cutting, pulling or grubbing, which means pulling out all the roots, are very labor intensive. The advantage is that people can be trained to discriminate between the native plants and invasives. Mechanical techniques include mowing and mastication and can be cost-effective but are limited to gentle terrain and like grazing may cause unacceptable levels of ground disturbance and compaction. Also, machines and animals may not be able to discriminate between the invasive plants being controlled and the native plants being retained. Fire is also being used to control invasive plant species most often as a facet of some integrated pest management approaches. If the invasive plant species being targeted produces a prolific amount of seed, timing these controls to prevent annual seed production will maximize control efforts. In biocontrol, a natural enemy such as a parasite, predator or disease organism is introduced into the environment of the invasive plant or, if already present, is encouraged to multiply and become more effective in reducing the number of invasive plants. However, some biocontrol programs have resulted in significant, irreversible harm to untargeted species and to ecological processes and must be used with caution informed by the lifecycles and complex interactions of targeted and nontargeted species. Finally, although chemical control, which involves the use of an herbicide to reduce invasive plant populations, is controversial, Peter Warner, environmental scientist for the California Department of Parks and Recreation, considers "herbicides to be one of many essential tools in reducing the spread of invasive plants". The Nature Conservancy provides a checklist to be used when considering the use of herbicides entitled, To Spray or Not To Spray? and is contained in the Weed Control Methods Handbook, which is an excellent resource that covers in depth each of the control methods. It can be downloaded from the website http://tncweeds.ucdavis.edu/handbook.html.

You can get an Invasive Plants brochure at the Navarro River Resource Center, the number for which is 895-3230. You can also visit the Mendocino Coast Cooperative Weed Management Area website at www.mcwma.org and see how you can get involved locally or visit the website of the California Invasive Plant Council at cal-ipc.org.

A portion of this production was gleaned from The Nature Conservancy Weeds website at tncweeds.ucdavis.edu and communication with Peter Warner of the California Department of Parks and Recreation and Tara Athan, botanist for the Mendocino Coast Cooperative Weed Management Area.

Tanoak to Energy

By Thembi Borras

Tanoak is a beautiful wood, we used it in our home for trim, baseboard and cabinet stock. Tanoak is hard and either clear boards or boards complex in character can be made from it. However, tanoak is a labor of love to process, minimizing the defect during drying being the trickiest part. Several attempts have been made to develop the infrastructure for processing tanoak into a viable product, foremost among them was Mendocino Redwood Company's attempt to make tanoak into tongue and groove flooring. Regardless of the many failed attempts to create a viable market for tanoak, landowners and forest managers continue to seek an economical means to balance the large amount of tanoak in certain landscapes with the desired conifer component.

Some forest managers use herbicides to gain this balance. Firewood operations are limited by the number of reputable firewood cutters, logistics, and that many small timers can't afford liability insurance. The best time to remove tanoak is when logging conifers, because the roads are open, the equipment is on site and the CDF plan under which you are operating is active. To do this however, you need some place to sell it and at this time, there is no viable market. Occasionally the chip market will pay enough per ton to justify hauling it to the closest pulp mill in Humboldt County, but this is usually at a net loss.

Recently, I was asked by a reader in Irmulco with a tanoak rich property, "How about conducting a poll to see how many folks would support the county pursuing a hardwood for biofuel project?".

One type of biofuel project could be a cogeneration plant that would burn wood to generate electricity. Another might be to convert biomass to biofuel. One advantage this market has over the furniture or flooring markets is the size and quality of the tree matters less, so there is less incentive to high grade the biggest and best trees from a managed forest. My guess is as much tanoak as conifer could be harvested in the County each year. If this were an adequate resource base, there are at least two inactive industrial sites previously used to process forest products that could serve as potential locations. Given that this topic has been penetrated to various depths over the last several decades, old-timers may already have answers to obvious questions like can it be done cleanly, is it cost-effective and is there public support? Given the high price of oil and interest in self-sufficiency, this may be a good time to once again consider this option for turning tanoak into energy.

Jackson Demo State Forest Draft Environmental Impact Report Alternatives Evaluation

By Thembi Borras

The Board of Forestry and Fire Protection has released a Draft Environmental Impact Report (DEIR) for the proposed management plan for JDSF and seeks public input. JDSF is 50,000 acres and is the largest of the eight Demonstration State Forests that the California Department of Forestry and Fire Protection (CDF) operates. Since 2001, timber harvest on JDSF has been suspended due to legal action; the DEIR for the proposed management plan is intended to move the status of management of JDSF from inactive toward active.

I evaluated the seven alternatives proposed in the DEIR based on silviculture, growth and yield and the use of herbicides, which I believe are essential issues.

Note: Uneven-Aged management includes prescriptions such as single tree selection and group selection. Even-Aged management includes prescriptions such as clearcutting, seed tree and shelterwood. Annual allowable harvest is projected out a minimum of 10 years.

Alternative A (minimal management)
Uneven-Aged Management/ Even-Aged Management: No harvest, no site preparation, no thinning, no planting.
Annual Allowable Harvest: Not applicable.
Herbicide Use: Limited for road maintenance.

Alternative B (continue 1983 plan)
Uneven-Aged Management: Yes.
Even-Aged Management: Yes.
Annual Allowable Harvest: 36 million board feet (MMBF)/year (nearly equal to the present estimated growth).
Herbicide Use: Yes.

Alternative C1 (CDF May 2002 DFMP, preferred Alternative by CDF)
Uneven-Aged Management: Yes, allowed on approximately 24,000 acres.
Even-Aged Management: Yes, allowed on approximately 11,000 acres.
Annual Allowable Harvest: 31 MMBF/year.
Herbicide Use: Yes.

Alternative C2 (CDF November 2002 Plan)
Uneven-Aged Management: Yes, allowed on approximately 22,500 acres.
Even-Aged Management: Yes, allowed on approximately 10,000 acres.
Annual Allowable Harvest: 31 MMBF/year.
Herbicide Use: Yes.

Alternative D (Citizens Advisory Committee proposal)
Uneven-Aged Management: Yes.
Even-Aged Management: No clearcutting. Other prescriptions restricted to limited demonstration.
Annual Allowable Harvest: 25 MMBF/year.
Herbicide Use: Herbicides would not be allowed in site preparation or vegetation control. There would be a three-year moratorium on chemical use for control of invasive species.

Alternative E (Late Seral Forests)
Uneven-Aged Management: Yes.
Even-Aged Management: No.
Annual Allowable Harvest: 8 MMBF/year.
Herbicide Use: No.

Alternative F (Older Forests Emphasis)
Uneven-Aged Management: Yes.
Even-Aged Management: No.
Annual Allowable Harvest: 19 MMBF/year.
Herbicide Use: Use herbicides only if other approaches fail.


Alternative D (Citizens Advisory Committee proposal), in my opinion, appears to have the greatest chance of successfully balancing environmental values, economic viability and public support. If there is enough public buy-in, then perhaps further legal wrangling can be avoided. Alternative D also best fits my vision of public forest management because it is strong on building inventory, strong on selection prescriptions and does not suggest incorporating herbicide use as a customary part of forest management. Building inventory and improving stand structure are cornerstones of sustainable forestry, although selection prescriptions do not inherently imply improved stand structure, this is only inherent in good decisions made on the ground regarding which trees will be cut and which will be left. Selection prescriptions done well are opportunities to take value from the forest and improve the transportation infrastructure, at the same time keeping pre harvest habitat the same as post harvest habitat, improving aesthetics by maintaining a continuous forest canopy and encouraging fewer large stems and minimizing adverse watershed effects through a low level of canopy removal.