Partial exclusion of precipitation: throughfall, stemflow and canopy interception in Eucalyptus plantations in southern Brazil

Gian Carlos Poleto,James Stahl,Mauro Valdir Schumacher,Aline Aparecida Ludvichak,Kristiana Fiorentin Dos Santos,Dione Richer Momolli,Clayton Alcarde Alvares

doi:10.4136/ambi-agua.2645

Abstract

Hydrological behavior in reforested watersheds is different from that under other forms of cover. The variation may be related to aspects intrinsic to species, planting density, physiological maturity, management system and climatic conditions. Periodically, climatic anomalies such as the case of La Ninã are observed, and these are responsible for the alteration of the rainfall regime and consequently generate water deficits in the southern region of Brazil. Water deficit is responsible for reducing growth and productivity for the Eucalyptus genus, in addition to causing changes in hydrological behavior in reforested watersheds. Accordingly, this study compared the partition of rainfall in throughfall, stemflow and canopy interception of eucalyptus trees submitted or not to partial exclusion of precipitation. In the open field, 3 rainfall collectors were installed, and in the stand, for each rain exclusion treatment, 9 throughfall collectors and 9 stemflow collectors were installed. Every two weeks for 12 months, the volume of the collectors was measured. The quantified precipitation was 1627 mm over a year. In the treatment without exclusion, 84.8, 2.9 and 12.3% referred to throughfall, stemflow and canopy interception, respectively, while in the treatment excluding rainfall 80.6, 2.3 and 17.2% referred to throughfall, stemflow and canopy interception. The regression adjustments for throughfall and stemflow showed satisfactory R2 coefficients.

Highlights

The forestry sector holds a prominent position in the Brazilian economy
Measurement of rainfall, throughfall and stemflow To quantify the rainfall (R), three collectors with a 20 cm catchment diameter were installed in an area adjacent to the eucalyptus stand at a height of 1.5 m above ground level
The month of December 2017 had the highest volume of R 371 mm, while the months of July 2017 and April 2018 registered the lowest volumes (0.00 and 21 mm) (Table 2)

Summary

INTRODUCTION

The forestry sector holds a prominent position in the Brazilian economy. Planted forests occupy 7.83 million hectares of the country, and the genus Eucalyptus represents 72% of this area. In addition to the interception of rainfall through the canopy of trees, the rapid growth of the Eucalyptus genus increases water consumption, losing it to the atmosphere through transpiration (Rodríguez Suarez et al, 2014; Jackson et al, 2005). Considering the species in the present study, Eucalyptus urophylla, Arcova et al (2018) reported 89.0%, 5.4% and 5.6% for throughfall, stemflow and canopy interception for a stand at 30-year-old, respectively. The precipitation event carries particles suspended in the atmosphere to the ground (Navar et al, 2009) These particles, added to the interaction with the canopy (throughfall and stemflow), leach the different tissues of the plant, increasing the nutritional contribution (Bhat et al, 2011; Schrumpf et al, 2006). The present study evaluated the partition of precipitation in Eucalyptus stands with and without partial exclusion of throughfall

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION