Effectiveness and Costs of Different Weed Control Methods AIming at Forest Restoration

Weeds in forest restoration projects can pose significant obstacles to the development of native species seedlings due to their high competitive potential, jeopardizing the success of restoration efforts. In this context, the present study aimed to evaluate the effectiveness of different weed control methods in the seedling vicinity as well as the associated costs of maintaining areas undergoing forest restoration. Six control methods were tested: chemical control using glyphosate herbicide, manual weeding, and three physical control methods using mulch, cardboard, and fiber mats, in addition to a no-intervention control treatment. The experiment was conducted in a randomized block design with five blocks, using the native species Peltophorum dubium and Guazuma ulmifolia. The analyzed variables included total height and stem diameter of the seedlings at 11 and 24 months after planting as well as the maintenance costs of the area and the control efficiency of each method. The absence of weed control negatively impacted the development of the tested species, both in terms of height and diameter. All control methods proved effective in managing weeds, with no statistically significant differences between treatments for height and diameter increments at 11 and 24 months after planting. Regarding maintenance costs over 24 months for a one-hectare area, the straw mulch method had the lowest cost at R$ 2,200.00, followed by chemical control (R$ 2,304.75), manual weeding (R$ 4,652.16), treated cardboard (R$ 6,489.80), and fiber bags (R$ 14,434.80).