A Review of Factors That Affect the Static Load-Bearing Capacity of Urban Trees

Abstract

Over the last 30 years, researchers have begun to employ biomechanical principles to understand the stability of urban trees. This review concentrates on literature pertaining to trees in temperate urban landscapes, but also includes relevant work from other disciplines and climates as appropriate. The load-bearing capacity of a tree depends on its size and shape and the material properties of its wood. As the trunk and branches increase in diameter, their load-bearing capacity increases. Material properties (e.g., moduli of elasticity and rupture) describe intrinsic wood stiffness and strength, which influence deflection under load and load-bearing capacity, respectively. In wood, material properties vary in relation to a variety of factors, including the direction of loading, moisture content, and tree age. Wood decay reduces a tree’s load-bearing capacity. Although practitioners have developed guidelines to assess its effect, existing guidelines should be investigated, refined or rejected on the basis of rigorous scientific testing. Static load tests have been developed to address this question, as well as investigate the likelihood of uprooting, which accounts for up to 35% of tree failures. While much has been learned, many questions remain about the static load-bearing capacity of trees growing in urban landscapes.

TreeMMoSys: A low cost sensor network to measure wind-induced tree response

“…Because a large number of trees are regularly damaged by storms, there is great interest in a comprehensive understanding of the processes that contribute to storm damage. Therefore, substantial efforts are being made to understand the formation and patterns of storm damage in forests [5] , [6] , [7] , [8] and urban trees better [9] , [10] .…”

Can Mechanical Strain and Aspect Ratio Be Used to Determine Codominant Unions in Red Maple without Included Bark

“…Branches become more rigid as they grow, and their primary function shifts away from sun branches with photosynthetic tissue to structural branches that hold smaller sun branches [47,[51][52][53][54]. As branch diameter increases, strain induced during bending should also increase, as strain increases with the distance from the pith [5,26,55,56]. We did not test the material properties of the wood in this study; as such, we do not know of the wood in the branch unions' proportion of juvenile to mature wood.…”

“…Arborists and urban forest managers maintain trees in a landscape that is dominated by humans where tree failure (whole tree or portions of a tree) can cause damage to infrastructure, personal property, or personal injury [1][2][3]. Many of these failures occur during heavy or extreme storm events such hurricanes, ice storms or heavy snow events [1,4,5]. The frequency of extreme weather events is increasing due to climate change [6].…”

Befestigung von Bauwerken in Bäumen mit Baumankern und doppelter Umreifung

“…untersucht und in einem Baumgutachten dokumentiert werden. Dieses Baumgutachten sollte bereits in Kombination mit einer Vorstatik die Tragfähigkeit des Baums (Widerstandseite) [4–7] mit den zusätzlichen Lasteinträgen durch das Bauwerk (Lastseite) vergleichen. Auf dieser Basis können ggf.…”