Dendrometric characterization of Cupressus lusitanica mill. planted under Pinus taeda L. shelter in southern Brazil

Background: We analyzed if C. lusitanica can be planted in a shelterwood system with P. taeda as the shelter stratum. The study was conducted in a 13-yr-old C. lusitanica stand under P. taeda canopy in Southern Brazil. Samples of these trees were measured in terms of diameter at breast height (DBH), total height, individual volume, and crown projection area. The species´ growing space efficiency (GSE) was also analyzed. A 10-meters distance criterion from P. taeda trees was applied to check their influence on C. lusitanica growth behavior through correlation. Results: The 36-yr-old P. taeda trees showed expressive means in the dendrometric variables, compatible with its age (mean DBH of 58 cm, total height 30 m, individual volume of 3.7 m³, and crown projection area of 128 m²). There was a statistically significant effect (p>0.05) of P. taeda cover on C. lusitanica diameter (mean of ~13 cm). Although not significant, an effect of P. taeda canopy was also observed on C. lusitanica height. The two species summed a basal area of 36.5 m² ha-1 and a crown projection area of 34,209.2 m² ha-1. A tendency of increasing GSE with increasing diameter was observed for both species. Conclusion: These results show that a shelterwood with C. lusitanica under P. taeda is possible, but further investigations with longer production cycles and with silvicultural treatments (i.e. thinnings and shelter removal) should be conducted for a better understanding of shelterwood systems with these species in southern Brazil in terms of growth performance and soil use sustainability.