ORCID Profile
0000-0001-8781-1970
Current Organisation
Charles Darwin University
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Publisher: MDPI AG
Date: 21-08-2020
DOI: 10.3390/SU12176796
Abstract: Agroforestry is often discussed as a strategy that can be used both for the adaptation to and the mitigation of climate change effects. The climate of southern Africa is predicted to be severely affected by such changes. With agriculture noted as the continent’s largest economic sector, issues such as food security and land degradation are in the forefront. In the light of such concerns we review the current literature to investigate if agroforestry systems (AFS) are a suitable response to the challenges besetting traditional agricultural caused by a changing climate. The benefits bestowed by AFS are multiple, offering ecosystem services, influence over crop production and positive impacts on rural livelihoods through provisioning and income generation. Nevertheless, knowledge gaps remain. We identify outstanding questions requiring further investigation such as the interplay between trees and crops and their combination, with a discussion of potential benefits. Furthermore, we identify deficiencies in the institutional and policy frameworks that underlie the adoption and stimulus of AFS in the southern African region. We uphold the concept that AFS remains an appropriate and sustainable response for an increased resilience against a changing climate in southern Africa for the benefit of livelihoods and multiple environmental values.
Publisher: MDPI AG
Date: 22-04-2022
DOI: 10.3390/F13050650
Abstract: Agroforestry systems hold potential for wood and tree biomass production without the need of felling trees. Branch wood harvesting provides access to considerable amounts of lignocellulosic biomass while leaving the tree standing. Aiming at alternatives for wood provision, we assessed the actual woody structure of a silvopastoral system in the African Savannah ecoregion, utilising terrestrial LiDAR technology and quantitative structure models to simulate branch removals and estimate harvesting yields. In addition, the stand structure and harvested wood were examined for the provision of four types of assortments meeting local needs, and operational metrics for each treatment were derived. The stand had large variability in woody structures. Branch harvesting interventions removed up to 18.2% of total stand volume, yielded 5.9 m3 ha−1 of branch wood, and delivered 2.54 m3 ha−1 of pole wood quality, retaining on average more than 75% of the original tree structures. Among the most intense simulations, a mean of 54.7 litres (L) of branch wood was provided per tree, or approximately 34.2 kg of fresh biomass. The choice of an ideal harvesting treatment is subject to practitioners’ interests, while the discussion on aspects of the operation, and stand and tree conditions after treatment, together with outputs, assist decision making. The partitioning of tree structures and branch removal simulations are tools to support the design of tending operations aiming for wood and tree biomass harvesting in agroforestry systems while retaining different functional roles of trees in situ.
Publisher: MDPI AG
Date: 02-02-2021
DOI: 10.3390/RS13030532
Abstract: Reduced solar radiation brought about by trees on agricultural land can both positively and negatively affect crop growth. For a better understanding of this issue, we aim for an improved simulation of the shade cast by trees in agroforestry systems and a precise estimation of insolation reduction. We present a leaf creation algorithm to generate realistic leaves to be placed upon quantitative structure models (QSMs) of real trees. Further, we couple it with an enhanced approach of a 3D model capable of quantifying shading effects of a tree, at a high temporal and spatial resolution. Hence, 3D data derived from wild cherry trees (Prunus avium L.) generated by terrestrial laser scanner technology formed a basis for the tree reconstruction, and served as leaf-off mode. Two leaf-on modes were simulated: realistic leaves, fed with leaf data from wild cherry trees and ellipsoidal leaves, having ellipsoids as leaf-replacement. For comparison, we assessed the shading effects using hemispherical photography as an alternative method. Results showed that insolation reduction was higher using realistic leaves, and that the shaded area was greater in size than with the ellipsoidal leaves or leaf-off conditions. All shading effects were similarly distributed on the ground, with the exception of those derived through hemispherical photography, which were greater in size, but with less insolation reduction than realistic leaves. The main achievements of this study are: the enhancement of the leaf-on mode for QSMs with realistic leaves, the updates of the shadow model, and the comparison of shading effects. We provide evidence that the inclusion of realistic leaves with precise 3D data might be fundamental to accurately model the shading effects of trees.
Publisher: MDPI AG
Date: 05-01-2023
DOI: 10.3390/SU15020968
Abstract: The assessment of the conservation status of urban forest remnants is essential for sustaining tree ersity in metropolitan cities. This study evaluated the composition and structure of forest remnants in four urban parks within the natural distribution of Montane Mixed Ombrophilous Forest in Curitiba (PR, Brazil). We allocated 66 plots of 100 m2 and recorded all trees with perimeters at breast height ≥ 15 cm. A total of 1256 in iduals from 44 botanical families and 117 tree species were identified, of which three are alien species. Tree density ranged from 1670 to 2095 trees ha−1, while the density of standing dead trees varied between 90 and 188 trees ha−1. We experienced values for the Shannon ersity index between 3.00 and 3.52 nats ind−1, which are comparable to the values for other non-urban forest remnants. Non-pioneer species represented 84.6% of the tree community (99 spp.), and 76% were zoochoric species (89 spp.). The research findings feed the discussion on the need of specific and integrated measures for the management of the urban parks reserved to the conservation of tree ersity in a specific phytoecological formation, while considering aspects of climate change and historical anthropisation.
Publisher: Wiley
Date: 2023
DOI: 10.1002/PPJ2.20073
Abstract: Tree training systems for temperate fruit have been developed throughout history by pomologists to improve light interception, fruit yield, and fruit quality. These training systems direct crown and branch growth to specific configurations. Quantifying crown architecture could aid the selection of trees that require less pruning or that naturally excel in specific growing/training system conditions. Regarding peaches [ Prunus persica (L.) Batsch], access tools such as branching indices have been developed to characterize tree‐crown architecture. However, the required branching data (BD) to develop these indices are difficult to collect. Traditionally, BD have been collected manually, but this process is tedious, time‐consuming, and prone to human error. These barriers can be circumnavigated by utilizing terrestrial laser scanning (TLS) to obtain a digital twin of the real tree. TLS generates three‐dimensional (3D) point clouds of the tree crown, wherein every point contains 3D coordinates ( x , y , z ). To facilitate the use of these tools for peach, we selected 16 young peach trees scanned in 2021 and 2022. These 16 trees were then modeled and quantified using the open‐source software TreeQSM . As a result, “in silico” branching and biometric data for the young peach trees were calculated to demonstrate the capabilities of TLS phenotyping of peach tree‐crown architecture. The comparison and analysis of field measurements (in situ) and in silico BD, biometric data, and quantitative structural model branch uncertainty data were utilized to determine the reconstructive model's reliability as a source substitute for field measurements. Mean average deviation when comparing young tree (YT) height was approx. 5.93%, with crown volume was approx. 13.26% across both 2021 and 2022. All point clouds of the YTs in 2022 showed residuals lower than 12 mm to cylinders fitted to all branches, and mean surface coverage greater than 40% for both the trunk and primary branching orders.
Publisher: RGSA- Revista de Gestao Social e Ambiental
Date: 07-08-2023
Abstract: Purpose: The study characterised the dynamics of the natural regeneration process of urban remnants in four Curitiba (PR, Brazil) urban parks, aiming to contribute to the green infrastructure management process in Araucaria Forest areas. Theoretical framework: Urban forests offer significant socio-environmental benefits, being relevant for maintaining ecosystem services for cities and their inhabitants. Studying the regeneration of forest remnants in urban environments is essential for analysing their conservation status. Method/design/approach: The floristic ersity, structure, and population dynamics of the shrub-regenerating component of urban forest remnants were studied through the analysis of phytosociological parameters and the similarity between the shrub-regenerating, and arboreal components was verified. Results and conclusion: Significant dissimilarity was found between the study areas' regenerating shrub and tree components. The forest remnant of the Municipal Zoo, located in a locality with greater integration of different green areas, showed the best conservation status and a more advanced process of forest succession. Research implications: The analysis of the natural regeneration of urban remnants serves as an essential diagnosis regarding their conservation status and the capacity of species to perpetuate in the place, in addition to inferring about the connectivity with other urban remnants, being of great importance for the planning of actions aimed at the management of urban forests. Originality value: Analyzing natural regeneration generates information on forest remnants' conservation status and resilience, which is essential for planning actions for urban forest management.
Publisher: Springer Science and Business Media LLC
Date: 02-10-2022
DOI: 10.1007/S10457-021-00697-5
Abstract: Light is a limiting resource for crops within integrated land use systems especially those including woody perennials. The amount of available light at ground level can be modified by artificially pruning the overstory. Aiming to increase the understanding of light management strategies, we simulated the pruning of wild cherry trees and compared the shading effects of the resulting tree structures over a complete growing season, with fine spatiotemporal resolution. Original 3D-tree structures were retrieved employing terrestrial laser scanning and quantitative structure models, and subjected to two pruning treatments at low and high intensities. By using the ‘shadow model’, the analogous tree structures created erse shaded scenarios varying in size and intensity of insolation reduction. Conventional pruning treatments reduced the crown structure to the uppermost portion of the tree bole, reducing the shading effects, and thus, shrinking the shaded area on the ground by up to 38%, together with the shading intensity. As an alternative, the selective removal of branches reduced the shading effects, while keeping a more similar spatial distribution compared to the unpruned tree. Hence, the virtual pruning of tree structures can support designing and selecting adequate tending operations for the management of light distribution in agroforestry systems. The evidence assembled in this study is highly relevant for agroecosystems and can be strategically used for maintaining, planning and designing integrated tree-crop agricultural systems.
Location: China
No related grants have been discovered for Rafael Bohn Reckziegel.