Use of Cardboard Disks for Crowning Seedlings in Reforestation

ABSTRACT The present study aimed to evaluate the effect of chemopreventive or water-repellent substances on the durability of cardboard disks used to crown forest tree species. The experiment presented a randomized block design with four repetitions and four sampling times (63, 133, 260 and 365 days) and was installed in Seropedica, RJ, in an area with Urochloa humidicola . Bamboo poles were used to simulate seedlings in the field and define the position of the experimental units. The treatments consisted of in natura cardboard, or treated with CuSO4 solution, pinus shellac, CuSO4 + pinus shellac, CuSO 4 + Sika®, pinus shellac + Sika®, and a second control with manual crowning. The cardboard crowning was effective at suppressing grass growth over all periods evaluated, independent of the treatment. After a year in the field, the cardboard disks treated with CuSO4 solution presented higher physical integrity with only 25% mass loss, against 60% mass loss in the control. The cardboard crowning also reduced soil temperature at the crown area by up to 15 °C in the 0 to 10 cm layer, in comparison with manual crowning. The results of this study indicate that the cardboard crowning method is efficient and has the potential to reduce the cost of weed control in reforestation.