Cost and efficiency of cutting lianas in a lowland liana forest of Bolivia

Liana cutting is a commonly suggested silvicultural practice aimed at reduc ing the negative impacts of lianas on timber production, bur few experiment al studies have been conducted to evaluate the cost and efficiency of this practice. In this study, we estimated the cost of cutting lianas in 12 plot s of 0.25 ha each in a densely liana-infested forest of lowland Bolivia, an d evaluated the efficiency of this silvicultural treatment in terms of the proportion of lianas missed, the density of resprouting liana stumps, and t he number of liana-infested trees after two years of an experimental Liana treatment. The cost of cutting lianas in this forest by locally hired laborers was 23. 6 (SE = 2.48) person-hours/ha. Considering local cost of labor and the U.S. -Bolivian currency exchange rate at the time of the study, this figure tran slates to ca $15/ha. Liana density decreased from 2471 (SE = 104.3) to 1.30 (SE = 24.2) liana stems greater than or equal to2 cm/ha immediately after cutting, because 5.5 percent of lianas were left uncut (missed). Slender Li anas were missed more often than lianas with large-diameter stems. Liana sp ecies that grow 2-3 m before they start to twine were also frequently misse d. Twenty-two percent of liana stumps greater than or equal to2 cm sprouted after cutting. Liana stumps with larger diameters sprouted more than stump s with smaller diameters. Most liana stumps produced only two sprouts. Two years after cutting, 78 percent of trees had no living lianas in their crow ns, in contrast to only 13 percent liana-free trees in the control plots. S ixty-four percent of trees still had hanging dead lianas two years after cu tting, but only 23 percent of trees were reinvaded hy lianas using dead Lia na stems as trellises. Liana cutting can efficiently reduce the number of lianas in liana-infest e d Forests, and the effects of cutting lianas last: for ae least two years; however, the treatment is expensive. Thus, we recommend that it is better t o view liana cutting as a preventive activity to avoid liana infestation, r ather than as a corrective measure after poor management. Liana cutting can be easily conducted along with other reduced-impact logging practices.