Trade-Offs among Release Treatments in Jack Pine Plantations: Twenty-Five Year Responses

We assessed 27 indicators of plant diversity, stand yield and individual crop tree responses 25 years post-treatment to determine long-term trade-offs among conifer release treatments in boreal and sub-boreal forests. This research addresses the lack of longer-term data needed by forest managers to implement more integrated vegetation management programs, supporting more informed decisions about release treatment choice. Four treatments (untreated control, motor-manual brushsaw, single aerial spray, and complete competition removal) were established at two jack pine (Pinus banksiana Lamb.) sites in Ontario, Canada. Our results suggest that plant diversity and productivity in boreal jack pine forests are significantly influenced by vegetation management treatments. Overall, release treatments did not cause a loss of diversity but benefitted stand-scale yield and individual crop tree growth, with maximum benefits occurring in more intensive release treatments. However, none of the treatments maximized all 27 indicators studied; thus, forest managers are faced with trade-offs when choosing treatments. Research on longer term effects, ideally through at least one rotation, is essential to fully understand outcomes of different vegetation management on forest diversity, stand yield, and individual crop tree responses.

Automated summary

The study evaluates the long-term trade-offs among different conifer release treatments in boreal and sub-boreal forests by assessing plant diversity, stand yield, and individual crop tree responses. The results show that vegetation management treatments significantly influence plant diversity and productivity in boreal jack pine forests, with more intensive release treatments providing maximum benefits. However, none of the treatments maximized all 27 indicators studied, highlighting the need for forest managers to make trade-offs when choosing treatments. Further research on longer term effects is essential to fully understand the outcomes of vegetation management on forest diversity and productivity.