Questionable Productivity

  • Studies Showing No Benefit
  • Studies Showing Benefits, but with Disclaimers
  • Questionable Assumptions of Herbicide Use

Studies Showing no Herbicide Benefit:

“There was no improvement in lodgepole pine growth from 1986 to 1995 as a result of treatment of the Dry Alder complex with glyphosate at 3 litres/ha or 6 litres/ha.   There were no significant differences in lodgepole pine height, 1-year height increment, stem diameter, stem volume, relative height growth, relative diameter growth, or vigour among the Control and the two glyphosate treatments.”-  Suzanne Simard, Jean Heineman, and Phil Youwe. Brushing and Grazing Effects on Lodgepole Pine, Vascular Plants, and Range Forage in Three Plant Communities in the Southern Interior of British Columbia, Ministry of Forests 1998, page 8.

“There was no increase in lodgepole pine height, stem diameter, or stem volume as a result of treatment of the Pinegrass Complex with either level of hexazinone or glyphosate.  Brushing and Grazing Effects on Lodgepole Pine, Vascular Plants, and Range Forage in Three Plant Communities in the Southern Interior of British Columbia, Ministry of Forests 1998, page 43.

“(Our studies) suggest that the diameter of many trees in the plantations may not improve following broadcast brushing treatments.  They also suggest that aspen competition was only one of several factors affecting conifer growth in the plantations, and that brushing will not necessarily alleviate the most important limitation to growth for many trees, except for those growing among high aspen densities.”- Suzanne W. Simard, Jean L. Heineman, W. Jean Mather, Donald L. Sachs, and Alan Vyse, Effects of Operational Brushing on Conifers and Plant Communities in the Southern Interior of British Columbia,Ministry of Forests, 2001, page 235.

“Spruce especially can handle a lot of vegetation before growth is reduced.  So in fact in a lot of cases the treatments were unnecessary.  Based on my research there were place where I had controls and treatments and there was no difference in the growth.”  - Craig Delong, former Ministry of Forests Research Ecologist, personal conversation, 2011.

Studies Showing Herbicide Benefits, but with Disclaimers:

“Even though the alder is competing for site resources and has reduced light levels, its presence may provide an additional source of nitrogen.  Height and diameter results suggest that spruce growth is not compromised by the alder.” G.J. Harper, L.J. Herring, and W.J. Hays-Byl, Conifer and Vegetation Response in the BWBSmw1 12 Years after mechanical and Herbicide Site Preparation, Ministry of Forests, 1997, page 18.

“You lost twenty years [over a 120 year rotation for spruce without spraying] but you still had the birch there and you had better quality trees because of the pruning, earlier crown lift and less taper, smaller knots…I don’t know what impact that will have on the quality.  The plantations that we have may be in many cases may be creating a pulp wood or reconsitituted wood products-type tree.”  Dr. Chris Hawkins, former forest science professor at UNBC and current director of research at Yukon College, personal conversation, 2011.

“These studies, as well as ours, indicate that brushing treatments that reduce birch density and height for sustained periods of time result in the largest conifer diameter responses, but that height responses do not always occur.”- Suzanne W. Simard, Jean L. Heineman, W. Jean Mather, Donald L. Sachs, and Alan Vyse, Effects of Operational Brushing on Conifers and Plant Communities in the Southern Interior of British Columbia,Ministry of Forests, 2001, page 301.

“Although birch is a strong competitor for light, it also benefits conifer seedlings by increasing nutrient availability and contributing to the health and diversity of the rhizosphere.  In the presence of birch roots, soil microbial populations are less likely to be nutritinally limited than in non-birch soils.  The diversity or richness of ectomycorrhizae on Douglas-fir roots has also been shown to increase in the presence of birch.  Ectomycorrhizae are well-know for their ability to enhance the uptake of water and nutrients, and they may also facilitate direct transfer of nutrients between two tree species.”-  Suzanne W. Simard, Jean L. Heineman, W. Jean Mather, Donald L. Sachs, and Alan Vyse, Effects of Operational Brushing on Conifers and Plant Communities in the Southern Interior of British Columbia,Ministry of Forests, 2001, page 304.

Questionable Assumptions of Herbicide Use:

  • That conifers are the only valuable resource
  • That the market will never demand aspen or birch
  • That aspen and birch play no role in forest health
  • That lodgepole pine won’t disappear from it’s present range
  • That it is efficient to forego the greater yields of all species in unsprayed forests for plantations of conifers that have less fibre overall.

“The main argument for maintaining (broadleaved species) is that it is not always possible to identify which individual species are critical to ecosystem sustainability, nor which species may be economically most important in the future.”- M.R.C. Massie, E.B. Peterson and N.M. Peterson, and K.A. Enns,  An assessment of the Strategic Importance of the Hardwood Resource in British Columbia, B.C. Ministry of Forests, page 33.

“This is a bit of a problem because we keep planting lodgepole pine as our species after harvesting. But we are planting it in places where we know, over the next hundred years, the climate is going to be less and less suitable for them.” Dr. Nicholas Coops, Forest Science Professor, UBC, Vancouver Sun March 1, 2011.

“The long and short of all of this is that now is a bad time in history to be a conifer tree of any kind,” Ed Berg, Alaskan ecologist, quoted in Andrew Nikiforuk, Empire of the Beetle, 28-9.

“A modelling study based on data collected in boreal forests of northeastern British Columbia suggests than mixed forests of aspen and spruce will produce greater biomass over several rotations than pure spruce forests of the same density.” Suzanne W. Simard, Jean L. Heineman, W. Jean Mather, Donald L. Sachs, and Alan Vyse, Effects of Operational Brushing on Conifers and Plant Communities in the Southern Interior of British Columbia,Ministry of Forests, 2001, page 235.

“The addition of trembling aspen and/or balsam poplar volume to the spruce volume in the mixed stand (i.e. untreated control plot) can offset the loss in spruce yield resulting from not applying the treatment.  The total timber yield (60 year rotation) projected for discing (509 m3/ha)and glyphosate (534 m3/ha) treated areas is less compared with the untreated control (545 m3/ha) areas.” - S.E. Hoyles, B.S. Biring., W.J. Hays Byl in: Twelve Year Conifer and Vegetation Responses to Discing and Glyphosate Treatments on a BWBSmw Backlog Site, Ministry of Forests, 1999, page 21.

 

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