Browsing by Author "Campoe, Otavio C."

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    Differences in rainfall interception among Eucalyptus genotypes
    (2023) Valverde, Juan Carlos; Rubilar, Rafael; Barrientos, Guillermo; Medina, Alex; Pincheira, Matias; Emhart, Veronica; Zapata, Alvaro; Bozo, Daniel; Espinoza, Yosselin; Campoe, Otavio C.
    Key messageHydrological indicators such as rainfall interception of Eucalyptus genotypes are essential to guarantee the water sustainability of forest plantations under climate change scenarios.Rainfall interception is a critical component of water balance in Eucalyptus plantations and may provide better water sustainability by reducing potential adverse effects under drought scenarios. This study evaluated rainfall interception of Eucalyptus globulus and E. nitens x globulus (high and low yield), E. nitens, E. badjensis, E. smithii, and E. camaldulensis x globulus. Rainfall, stemflow, throughfall, and interception (calculated as rainfall-stemflow-throughfall) were measured for 2 years (2020-2022) and correlated with plantation characteristics [diameter at breast height, total height, stem growth, and leaf area index (LAI)]. Our results showed an average rainfall of 1063.6 mm year(-1); only stemflow did not show differences among genotypes with an average value of 193.4 mm year(-1) (18.2% of annual rain). In contrast, throughfall and interception presented significant differences among genotypes, and both parameters showed a strong relationship with LAI. Therefore, three independent groups were obtained: E. badjensis and E. smithii showed the highest LAI (average 5.7 m(2) m(-2)) with 517.0 mm year(-1) of average interception and 427.6 mm year(-1) of average throughfall (48.6% and 40.2% respectively). For E. globulus (low-yield), E. nitens x globulus (low-yield), and E. nitens, that showed the lowest LAI (average 3.3 m(2) m(-2)), average throughfall reached 730.8 mm year(-1) (68.7%), and average interception reached 197.3 mm year(-1) (18.5%). Finally, E. globulus (high-yield), E. nitens x globulus (high-yield), and E. camaldulensis x globulus with an average LAI of 4.5 m(2) m(-2), average interception reached 345.2 mm year(-1) (32.5%), and average throughfall reached 602.7 mm year(-1) (56.7%). Our results suggest that understanding differences between taxas/genotypes may contribute to developing hydrological indicators that may improve estimates of plantation water sustainability under water scarcity climate change scenarios.
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    Evaluating the Influence of Row Orientation and Crown Morphology on Growth of Pinus taeda L. with Drone-Based Airborne Laser Scanning
    (2024) Sumnall, Matthew J.; Carter, David R.; Albaugh, Timothy J.; Cook, Rachel L.; Campoe, Otavio C.; Rubilar, Rafael A.
    The tree crown's directionality of growth may be an indicator of how aggressive the tree is in terms of foraging for light. Airborne drone laser scanning (DLS) has been used to accurately classify individual tree crowns (ITCs) and derive size metrics related to the crown. We compare ITCs among 6 genotypes exhibiting different crown architectures in managed loblolly pine (Pinus taeda L.) in the United States. DLS data are classified into ITC objects, and we present novel methods to calculate ITC shape metrics. Tree stems are located using (a) model-based clustering and (b) weighting cluster-based size. We generated ITC shape metrics using 3-dimensional (3D) alphashapes in 2 DLS acquisitions of the same location, 4 years apart. Crown horizontal distance from the stem was estimated at multiple heights, in addition to calculating 3D volume in specific azimuths. Crown morphologies varied significantly (P < 0.05) spatially, temporally, and among the 6 genotypes. Most genotypes exhibited larger crown volumes facing south (150 degrees to 173 degrees). We found that crown asymmetries were consistent with (a) the direction of solar radiation, (b) the spatial arrangement and proximity of the neighboring crowns, and (c) genotype. Larger crowns were consistent with larger increases in stem volume, but that increases in the southern portions of crown volume were consistent with larger stem volume increases, than in the north. This finding suggests that row orientation could influence stem growth rates in plantations, particularly impacting earlier development. These differences can potentially reduce over time, especially if stands are not thinned in a timely manner once canopy growing space has diminished.