EP 1135.03

Project Title:

A Comparison of Mulch Mat and Herbicide Treatments for Reducing Grass Competition in the IDFww

Reference Numbers:

EP 1135.03

Project Start/End Dates:

April 2006-April 2008

Keywords:

growth and yield modelling, vegetation management, soil moisture, site productivity, grass competition, herbicides, glyphosate, cutting treatments, mulch mats, Tree and Stand Simulator (TASS), Table Interpolation Program for Stand Yields (TIPSY), stand development modelling, Southern Interior Forest RegionTop

MFR Initiatives Supported:

timber supply, vegetation management practices, mitigation, industry competitiveness, forest inventory, Interior Douglas-fir management

BEC Units:

IDF

Location:

Nahatlatch River Lookout, Boston Bar, BC. Chilliwack Forest District

Objectives:

  • To help determine which treatment options are appropriate for enhancing the survival and growth of conifers;
  • To compare the effectiveness of glyphosate, hexazinone, and porous mulch mats for reducing grass competition and improving survival and growth of Douglas-fir seedlings;
  • To compare the effectiveness of two rates of glyphosate application (2.1 and 1.0 kg a.i./ha), and two brush mat types (Arbortec® Brush Blanket, and Tredegar® Tree Mat) and sizes (90 cm2 and 120 cm2).
  • To model the long-term growth and yield implications of vegetation management treatments.Top

Summary:

Vegetation management treatments are often used to ensure that young conifer plantations achieve free-growing requirements. Grasses, herbs and low shrubs commonly compete with conifer seedlings following disturbance of forests in the Interior Douglas-Fir zone.

A study area near Boston Bar was established in 1993 to examine the effects of vegetation control treatments on the survival and growth of Douglas-fir seedlings in competition with grasses and herbs. Vegetation control treatments included pre-planting applications of the herbicides glyphosate and hexazinone, and plastic mulch mats. Seedling measurements were collected in year 0 (pre-treatment), 1, 2, 3, 4, 5, 7, 10, and 15 years after planting.

Ten-year results indicate that application of herbicides enhanced the survival, diameter, and height growth of planted Douglas-fir seedlings (Harper et al. 2005). These herbicide treatments provided effective control of grass and herbaceous vegetation for three to four growing seasons. Plastic mulch mats did result in improvements in growth and survival, but these were not statistically different from untreated seedlings. The results of soil moisture monitoring suggested delay in the onset of soil drought as a key determinant of seedling growth improvement.

Results from these measurements were entered into TASS to project Douglas-fir volume growth and rotation age for the various vegetation management treatments (Harper et al. 2008).

Related Publications:

Biring, B.S., and P.G. Comeau. 2000. Testing forest vegetation management options. In FORREX Series, From Science to Management and Back: A Science Forum for Southern Interior Ecosystems of British Columbia FORREX Forest Research Extension Society, Kamloops, B.C. [link]

Comeau P.G., Biring B.S., Harper G.J. 1999. Conifer response to brushing treatments: A summary on British Columbia, B.C. Min. For., Res. Br., Victoria, B.C. Exten. Note 41.

Harper, G., K. Polsson and J. Goudie. 2008. Modelling vegetation management treatments with the Tree and Stand Simulator. For. Chron. 84(1): 53-59.

Harper, G.J., P.G. Comeau and B.S. Biring. 2005. A comparison of herbicide and mulch mat treatments for reducing grass, herb, and shrub competition in the BC Interior Douglas-fir zone - ten year results. West. J. Appl. For. 20(3): 167-176. [link]

Harper, G.J., P.G. Comeau and B.S. Biring,W.J. Reid and P. Fielder. 1998. A comparison of mulch mat and herbicide treatments for reducing grass competition in the IDFww. B.C. Min. For., Res. Br., Victoria, BC. Exten. Note 27.

Harper, G., P. Comeau, B. Biring, and S. Andersson. 1996. Testing Forest Vegetation Management Options. In Expert Committee on Weeds: Proceedings of the 1996 National Meeting. B.C. Min. For., Res. Br., Victoria, B.C. Top

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Figure 1. View of research site located above the Nahatlatch River, Boston Bar (1996).   Figure 2. Nahatlatch Plot 6-b three years after treatment (1996).   Figure 3.  Nahatlatch River – glyphosate treatment plot.
         
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Figure 4. Nahatlatch River – Hexazinone treatment plot.   Figure 5. Nahatlatch River – control plot.   Figure 6. Spot application of glyphosate around Douglas-fir seedling (June 1993).
         
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Figure 7. Douglas-fir seedling with Tredegar 90 x 90 cm mulch mat (June 1993). Note the well-developed herb and grass competition.   Figure 8. Douglas-fir seedling from the 2.1 kg ai/ha glyphosate treatment four growing seasons after application (April 1997).   Figure 9. Tredegar mulch mat plot 7 in fall of 2007 (15 years post treatment).
         
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Figure 10. Hexazinone plot fall of 2007(15 years post treatment).   Figure 11.  Control plot fall of 2007 (15 years post treatment).    


Contact Person: George Harper, Research Scientist, Stand Development
Email: George.Harper@gov.bc.ca
 

Please direct questions regarding webpage to For.Prodres@gov.bc.ca
Updated April 2008