Action: Use herbicides to thin trees
Key messagesRead our guidance on Key messages before continuing
- One replicated, controlled study in Canada found no effect of using herbicide to thin pine trees on total plant species richness.
Although the use of herbicides is often not recommended as a conservation tool, in some cases it is used to increase forest structural diversity.
Supporting evidence from individual studies
A replicated, controlled study in 1993-1998 in temperate lodgepole pine Pinus contorta forest in British Columbia, Canada (Sullivan et al. 2002) found no effect of using herbicide to thin lodgepole pine on total tree density or on total plant species richness. There was no effect of herbicide on the number of trees (herbicide: 4,180; control: 7,648/ha) or number of plants species (herbicide: 24; control: 23/treatment unit). Data were collected in 1998 in herbicide (using glyphosate herbicide to retain 1,000 stems/ha) and control treatment units (2-13 ha). Units were established in 1993 in each of three study areas.