Action: Apply herbicides after restoration planting
- One replicated, randomized, controlled study in the USA found that controlling vegetation using herbicides after restoration planting decreased plant species richness and diversity.
Harvesting and replanting have substantial effects on forest biodiversity conservation and maintenance of long-term productivity. Herbicides have been extensively evaluated for their potential to release planted trees from competing vegetation.
Supporting evidence from individual studies
A replicated, randomized, controlled study in 1999-2006 in temperate coniferous forest in Washington State, USA (1) found that controlling vegetation using herbicides after restoration planting decreased plant species richness and diversity. Species richness (control: 24; herbicide: 17) and diversity (Simpson's index control: 0.83; herbicide: 0.35) were lower in treated plots. Data were collected in 2006 in two plots (30 × 85 m) of each control and herbicide (annual herbicide applications) treatments in each of four blocks that had been clearcut in 1999. In all plots tree trunks were removed and Douglas-fir Pseudotsuga menziesii seedlings were planted in 2000.