Rainfall partitioning in two native tree legumes in the Andean region, Colombia

Abstract Introduction: Understanding the hydrological balance and canopy structure in forest ecology and reforestation can predict the productivity of plantations. Objectives: To monitor an incident rainfall partitioning in a plantation of Schizolobium parahyba (Vell.) S. F. Blake and Samanea saman (Jacq.) Merr. and its relationship with canopy openness and leaf area index. Materials and methods: Incident rainfall partitioning was monitored for one year in a plantation of S. parahyba (4.4-5.4 years) and S. saman (5.8-6.8 years) in Rionegro, Santander, Colombia. Each plantation had linear rain gauges installed under the canopy and around the stem of the trees selected. Results and discussion: Throughfall (Tf), canopy interception losses (I) and stemflow (Sf) in the 12 months corresponded to 77.5, 22.3 and 0.44 %, respectively, in relation to open precipitation for S. parahyba (2 270 mm) and to 84.7, 15.3 and 0.05 %, respectively, for S. saman (2 140 mm). For both species, Ip and effective precipitation were higher (P < 0.05) in the two dry periods of the year, while I and Sf were higher in the two rainy periods. Canopy openness was correlated only with I and Tf in S. saman, while leaf area index was not correlated with any variable. Conclusion: Rainfall partitioning points out different paths in the same studied environment. It is important to analyze the hydrological processes in reforestation environments by taking into account the morphology of the species involved.