Effects of mixed native species plantations on the wood anatomy and quality of eucalyptus

Abstract

Hybrid Eucalyptus urophylla × Eucalyptus grandis plantations are widely established in Brazil due to their rapid growth, adaptability, and high wood quality. However, extensive monoculture systems have raised environmental and economic concerns, including biodiversity loss, soil degradation, and reduced water availability. Mixed plantations incorporating native species have been proposed as a sustainable alternative, yet information on how these systems affect Eucalyptus wood anatomical traits remains limited. This study compared wood anatomy of Eucalyptus grown under monoculture and mixed plantation systems. Twelve trees from each treatment were sampled at the Federal University of Lavras experimental site (Santo Antônio do Amparo, MG), and analyses were conducted in the Wood Anatomy Laboratory at UFLA. Fiber, vessel, ray characteristics and wood density were evaluated microscopically, complemented by scanning electron and light microscopy. Mixed plantations showed higher fiber diameter, fiber length and fiber wall thickness, while fiber lumen diameter was greater in monoculture. Most ray traits were enhanced in mixed systems, except ray width. Vessel diameter was larger in monoculture, whereas vessel frequency was higher in mixed plantations. Wood density followed similar trends to anatomical traits. Microscopic observations confirmed structural differences between planting systems. Density showed relation with vessel frequency, vessel diameter, ray frequency and fiber diameter. Overall, mixed plantations promoted improved wood anatomical characteristics compared to monoculture. These findings provide new insights into how planting systems influence Eucalyptus wood structure and highlight the potential of mixed plantations to enhance wood quality and support sustainable forest management.