Cost and Efficiency of Cutting Lianas in a Lowland Liana Forest of Bolivia 1

Liana cutting is a commonly suggested silvicultural practice aimed at reducing the negative impacts of lianas on timber production, but few experimental 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 plots of 0.25 ha each in a densely liana‐infested forest of lowland Bolivia, and evaluated the efficiency of this silvicultural treatment in terms of the proportion of lianas missed, the density of resprouting liana stumps, and the 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 translates to ca $15/ha. Liana density decreased from 2471 (SE = 104.3) to 130 (SE = 24.2) liana stems >2 cm/ha immediately after cutting, because 5.5 percent of lianas were left uncut (missed). Slender lianas were missed more often than lianas with large‐diameter stems. Liana species that grow 2–3 m before they start to twine were also frequently missed. Twenty‐two percent of liana stumps a2 cm sprouted after cutting. Liana stumps with larger diameters sprouted more than stumps with smaller diameters. Most liana stumps produced only two sprouts. Two years after cutting, 78 percent of trees had no living lianas in their crowns, in contrast to only 13 percent liana‐free trees in the control plots. Sixty‐four percent of trees still had hanging dead lianas two years after cutting, but only 23 percent of trees were reinvaded by lianas using dead liana stems as trellises. Liana cutting can efficiently reduce the number of lianas in liana‐infested forests, and the effects of cutting lianas last for at least two years; however, the treatment is expensive. Thus, we recommend that it is better to view liana cutting as a preventive activity to avoid liana infestation, rather than as a corrective measure after poor management. Liana cutting can be easily conducted along with other reduced‐impact logging practices. RESUMES El corte de lianas es una práctica de manejo comunmente recomendada para reducir los impactos negatives de las lianas en la producción forestal, pero existen pocos estudios experimentales que evaluen los costos y la eficiencia de dicha práctica. En este estudio estimamos el costo del corte de lianas en 12 parcelas de 0.25 ha cada una en un bosque densamente infestado de lianas en Bolivia, y evaluamos la eficiencia de este tratamiento en términos de la proporción de lianas no cortadas, de la densidad de lianas que rebrotan, y el número de árboles infestados con lianas dos años despues de un tratamiento del corte experimental de lianas. El costo de cortar lianas en este bosque por trabajadores locales fue de 23.6 (EE=2.48) horas‐persona/ha. Considerando el costo de labor y el intercambio monetario entre Bolivia y los EUA al tiempo del experimento, esta figura se traduce a ca 15 dólares EUA/ha. La densidad de lianas se redujo de 2471 (EE=104.3) a 130 (EE = 24.2) tallos de liana ≥2 cm/ha inmediatamente despues del corte, porque 5.5 por ciento de las lianas no se cortaron. Las lianas más delgadas fueron cortadas con mayor frequencia que las lianas más gruesas. Las especies de lianas que crecen