Variability and Balance of Crown Projection of Trees Planted on Sidewalks of Three Brazilian Cities

Abstract

Tree crown form can be used as a variable to the comprehension of factors that influence tree growth, mainly maintenance practices and interactions with urban structures, but also the potential risks that can exist. In this research, we aimed to evaluate crown projection unbalance of trees planted on sidewalks of three Brazilian cities, in order to determine the existence and the sort of asymmetry and crown angle formed in relation to the central axis of the trunk. We measured the length of four crown projection radii and compared them by means of Kruskal-Wallis Test. Each one of the crowns was framed in one of the four asymmetry classes to verify the uniformity of projection in relation to the central axis of the trunk. We also determined the distance between central axis of the trunk and crown centroid, with respective angle formed, in order to characterize the unbalance of crown projection. There was a significant difference among crown projection radii, with greater values to radius faced to street and the smallest ones faced to buildings. In the three cities evaluated there were a predominance of trees framed on class 3 of asymmetry, which represents the model with the greatest deformations on crown of trees. We observed the lowest mean angle of crown centroid projection with distinctions among species sampled in Bonito.

Interactive responses of root and shoot of camphor tree (Cinnamomum camphora L.) to asymmetric disturbance treatments

“…The below- and above-ground growth space of many street trees are often narrow, resulting in tree weakness and even mortality ( Limoges and Apparicio, 2018 ; Yan et al., 2019 ). Asymmetric tree architecture can be found near buildings, driveways, and river banks in urban areas, which also detracts from tree stability ( Rahardjo et al., 2009 ; Volder et al., 2009 ; Kontogianni et al., 2011 ; Bobrowski et al., 2017 ). Definite asymmetric correlation between the biomass distribution of the root system and shoots is the key to understanding the spatial interactions of below- and above-ground biomass.…”

“…Crown asymmetry is always found in natural forests because of crown avoidance to limit competition with neighbors ( Getzin and Wiegand, 2007 ). In cities, tree crowns are often biased away from buildings and root systems develop away from gray infrastructures ( Kontogianni et al., 2011 ; Bobrowski et al., 2017 ) to maximize growth potential. Generally, different viewpoints on the root–shoot architectural relationships exist.…”

Post-Pruning Growth of Some Afforestation Species in the Metropolitan Region of Belo Horizonte, Minas Gerais State, Brazil

“…Evaluating the behavior by species, Pata-de-Vaca, Jacarandá-Mimoso, Alfeneiro, and Espatódea presented a high positive correlation between sprout development and pruned crown volume. That is to say, in principle, the higher pruning intensity (up to 30% of the crown) for these species results in higher sprouting and possibly greater need for intervention (Bobrowski et al, 2017). However, for Mangueira, Munguba, and Paineira, there was an inverse behavior, resulting in a high negative correlation, or in other words, the greater intervention in the crown would generate greater stress in the plant, causing less vigor in shoots (Jacob Neto et al, 2016).…”

Sustainable Urban Streetscape: Managing trees as green infrastructure

“…Unfortunately, improper pruning can even be one of the terrible things that can drive the tree to confront with wounds. The process of recovering take place very slowly, depending on the size of the cut and the health of the trees (Bobrowski et al, 2017). Pruning with the improper method will bring an opening for the insects, which indirectly allow the trees to get infected.…”