Effects of lianas on growth and regeneration of Prioria copaifera in Darien, Panama

We conducted a silvicultural experiment to evaluate the effects of lianas on the stem diameter growth of Prioria copaifera (cativo), a valuable timber tree in Panama. Dalbergia brownei, a leguminous liana, is abundant in many riverine P. copaifera-dominated swamp forests in Panama's easternmost province of Darien, particularly in logged areas. In a forest along the Balsas River, P. copaifera dominated the forest with 96.6% of the total arboreal basal area of 34.8 m(2) ha(-1) (trees greater than or equal to10 cm dbh) while D. brownei comprised 96.9% of the total liana basal area of 3.4 (2) ha(-1) (stems greater than or equal to1 cm dbh). After classifying liana infestation as severe or minor for the crown of every tree greater than or equal to4 cm dbh in six 25 m x 25 m plots, we cut all lianas in three randomly chosen plots. Prior to treatment 53% of trees were severely infested, 31% had minor infestation, and 16% were liana-free. During the 5 years after treatment, mean annual diameter growth of cativo trees doubled in plots where all lianas were cut compared to control plots, regardless of severity of prior liana infestation. Prioria regeneration was scarce in heavily vine-infested forest compared to nearby permanent plots in forest with low liana infestation. At a cost of only 16 person-hours ha(-1), these results suggest that a small investment in cutting lianas can greatly increase wood production in degraded cativo forests. (C) 2003 Elsevier B.V. All rights reserved.