Branch-to-Stem Diameter Ratio Affects Strength of Attachment

Abstract

Strength of branch attachment in Acer rubrum L. was related to the ratio of diameter of the branch relative to the diameter of the stem to which the branch was attached (aspect ratio). Linear correlation coefficients ranged from ­0.25 to ­0.90 between aspect ratio and load (force) required to separate branches from stems at the branch union. Slopes of the lines describing this relationship increased with increasing branch diameter. This indicated that larger branches required greater force to pull them from the trunk provided they were small compared to the trunk. However, diameter had less of an influence on force required to pull codominant stems apart. Force per unit of branch cross-sectional area was related (R2 = 56%) to aspect ratio, indicating that a branch of a given size was better secured to the tree if it was attached to a much larger stem than to a stem of equal size. Angle of attachment was not related to strength of branch attachment. Codominant stems were far easier to split apart than branches that were small relative to stem size. Codominant stems broke by separating at the union; branches failed by breaking at or near the collar. This information has implications for arborists climbing trees and will help guide development of pruning strategies.

The Impact of Visual Defects and Neighboring Trees on Wind-Related Tree Failures

“…As might be expected given their location in the tree, weak branch attachments were associated with a smaller proportion of whole tree failures (Figure 3). Although many studies have quantified the reduced load-bearing capacity of weak branch attachments [48][49][50][51], they did not fail in 78% of trees in which they were the defect of primary concern. The comparatively low failure rate of weak branch attachment aligned with previous studies of tree failures following a hurricane [19] and a snowstorm [47], suggest that it may not be as serious a defect as considered.…”

Optimization and experimental study on structural parameters of bio-inspired tarsus compliant end-effector to reduce the risk of fruit sliding out from end-effector for cherry tomato harvesting

“…4,5 RSM-BBD has been widely used in agricultural optimization research. 5,20,[25][26][27][28] In Table 3, based on RSM-BBD method, the experimental design of four factors at three levels was carried out by design expert 6.0.8 software. ESGA was considered as the response variables.…”

“…19 Based on this method, Bu et al found that the horizontal pull with a bending and twisting motion is the potential optimal combination of robotic apple harvesting. 20 Hence, in order to prevent the captured fruit from slipping in the end-effector and significantly increase the success rate of picking, a design and optimization method of a bio-inspired tarsus compliant end-effector was proposed. In the research, Experiments were designed according to response surface methodology-box Behnken design by maintaining three levels of four process parameters—length of the offset segment tarsomere (OSL), angle of the inclined segment tarsomere (ISA), thickness of the extended segment tarsomere (EST), and length of the extended segment tarsomere (ESL).…”

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

“…Research has found that codominant unions are less stable than lateral branch unions [9][10][11][12][13]. Codominant stems arise from simultaneous vegetative development of axillary buds at the branch apex or from simultaneous development of collateral buds (dormant or adventitious), likely after the loss of apical/terminal end of the main growth axis [13]. Additionally, species that have opposite branch arrangements are prone to codominant branching [14,15].…”

“…Being able to identify less stable branch unions more accurately would allow urban forest managers to reduce failures prior to pending extreme storm events. Some codominant branch unions have been shown to have lower load-bearing capacity than lateral branch unions [9][10][11][12][13], thus arborists often considered codominant unions to have a higher likelihood of failure than lateral branches. When included bark is present, the union is considered less stable [12,[16][17][18] due to inherent structural defect and lack of cross-lamination of grain between branch and stem wood.…”