Canadian Forest Service Publications

Ten years of vegetation succession following ground-applied release treatments in young black spruce plantations. 2004. Pitt, D.G.; Wagner, R.G.; Towill, W.D. Northern Journal of Applied Forestry 21: 123-134.

Year: 2004

Issued by: Great Lakes Forestry Centre

Catalog ID: 25152

Language: English

Availability: PDF (request by e-mail)

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Responses of planted black spruce [Picea mariana (Mill.) BSP] and associated vegetation were studied for 10 years after conifer release options on two northeastern Ontario sites. Six treatments were compared to untreated check plots, including directed foliar application of glyphosate herbicide, basal bark treatment with triclopyr herbicide, glyphosate capsule injection with the EZ-Ject system, spot-treatment with hexazinone herbicide, manual cutting with brushsaw, and five growing seasons of annual vegetation removal with repeat applications of glyphosate. Ten years after treatment, black spruce survival averaged 86% and varied little among treatments (P > 0.5). Annual vegetation removal treatments resulted in nearly complete domination by spruce, with treated trees exhibiting 16–55% gains in height and 112–476% gains in stem volume growth over untreated trees. Despite rigorous vegetation control on these plots, each of the vegetation groups studied were well represented at the end of the observation period, including deciduous trees, tall shrubs, low shrubs, forbs, ferns, and grasses/sedges. Directed foliar treatment provided good control of herbaceous and woody vegetation around individual crop trees, providing an 8–46% gain in height and a 43–246% gain in stem volume growth. Both spruce and hardwoods shared dominance on these plots. Spot treatments with hexazinone provided similar short-term reductions in herbaceous vegetation, but tended to release shrub species that had a negative net effect on spruce growth. The other release treatments provided only short-term reductions in woody vegetation, which ultimately led to young stands dominated by deciduous tree species.