An experimental investigation of the effects of dynamic loading on coniferous trees planted on wet mineral soils

Rodgers, M.; Casey, Anne L.; McMenamin, C.; Hendrick, E.

doi:10.1017/cbo9780511600425.012

Cited by 17 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, water content below and underneath the root plate leads to hydraulic fracturing in the soil due to tree loading. The fracturation is subjected to a lower moment than the maximum turning moment (Rodgers et al 1995). In addition, a crack first forms under the stem and spreads to windward and leeward positions (Coutts 1986).…”

Section: Discussionmentioning

confidence: 99%

Root anchorage of hinoki (Chamaecyparis obtuse (Sieb. Et Zucc.) Endl.) under the combined loading of wind and rapidly supplied water on soil: analyses based on tree-pulling experiments

et al. 2011

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 99%

Root anchorage of hinoki (Chamaecyparis obtuse (Sieb. Et Zucc.) Endl.) under the combined loading of wind and rapidly supplied water on soil: analyses based on tree-pulling experiments

et al. 2011

View full text Add to dashboard Cite

“…In the second case, the decisive factors could be the long-term strain of swaying and the resultant material fatigue or loosening of soil cohesion. Swaying or shaking experiments (White et al 1976;Rodgers et al 1995) showed that after a long time, the soil around swaying trees can lose its properties and the swaying behaviour of the trees changes.…”

Section: Multifactor Analysismentioning

confidence: 99%

Vulnerability of spruce (Picea abies) and beech (Fagus sylvatica) forest stands to storms and consequences for silviculture

et al. 2006

View full text Add to dashboard Cite

The form and magnitude of storm damage and stand disclosure patterns were assessed in 332 randomly chosen pure and regular stands of spruce (Picea abies L.) and beech (Fagus sylvatica L.) after storm LOTHAR, within a region of the Swiss Midlands. This data was analysed in relation to maximal wind speed, measured with Doppler radar techniques and other influential factors such as relief, allometric characteristics, silvicultural history, and neighbourhood. In addition, storm damage, assessed from aerial photographs over an extended perimeter (about 70,000 ha) was considered. A storm of the magnitude of LOTHAR (December 26 1999), with an average maximal wind speed of 45 m s À1 (160 km h À1 ) appears to have a highly chaotic wind field structure, with great spatial and temporal variation of wind gusts. Wind speeds were not a significant predictor for damage in spruce stands and only weakly influential for beech. The consequences of this high randomness were analysed to estimate the return time of such a storm at the stand level. It lies between 86 and 113 years for spruce, 357 and 408 for beech. Only a few independent variables were significant and the overall explanatory strength of the model was unexpectedly low (R 2 =0.07 for spruce and 0.30 for beech). Among the more reliable predisposing factors were mixture and aspect combined with gradient. An admixture of 10% or more broadleaved tree species or wind-firm conifers like Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] significantly reduced the vulnerability of spruce stands (by a factor of more than three). On wind-exposed aspects, damage was more than twice the average. Steeper slopes caused a significant reduction in susceptibility (by a factor of six for slopes over 50%, in comparison to gentle slopes <20%). Other factors such as height to diameter ratio of trees or time since last thinning did not appear to be significant predictors.

show abstract

“…One of the most convenient of these is the half-power (band-width) method, whereby the damping ratio is determined from the frequencies at which the response amplitude is reduced to the level 1 ffiffi ffi 2 p times its peak value (Clough and Penzien 1993). These methods have not been used in previous studies on tree damping, but equipment developed by O'Sullivan and Ritchie (1992) and Rodgers et al (1995) could be used to excite the trees at different frequencies. However, Rodgers et al (1995) found that trees subjected to this type of forced loading eventually begin to oscillate in an elliptical pattern.…”

Section: Measurementmentioning

confidence: 99%

“…These methods have not been used in previous studies on tree damping, but equipment developed by O'Sullivan and Ritchie (1992) and Rodgers et al (1995) could be used to excite the trees at different frequencies. However, Rodgers et al (1995) found that trees subjected to this type of forced loading eventually begin to oscillate in an elliptical pattern. In such situations, data would need to be ignored.…”

Section: Measurementmentioning

confidence: 99%

Natural sway frequencies and damping ratios of trees: concepts, review and synthesis of previous studies

Moore

Maguire

2004

Trees - Structure and Function

126

114

View full text Add to dashboard Cite

Previous studies that measured the natural frequencies and damping ratios of conifer trees were reviewed and results synthesized. Analysis of natural frequency measurements from 602 trees, belonging to eight different species, showed that natural frequency was strongly and linearly related to the ratio of diameter at breast height to total tree height squared (i.e., DBH/H 2 ). After accounting for their size, pines (Pinus spp.) were found to have a significantly lower natural frequency than both spruce (Picea spp.) and Douglas-fir (Pseudotsuga spp.). Natural sway frequencies of de-branched trees were significantly higher than those of the same trees with the branches intact, and the difference increased with an increasing ratio of DBH/H 2 . Damping mechanisms were discussed and methods for measuring damping ratio were presented. Analysis of available data suggested that internal damping ratios were typically less than 0.05 and were not related to tree diameter. External damping was mainly due to aerodynamic drag on the foliage and contact between the crowns of adjacent trees. Analysis of data from previous wind-tunnel studies indicated that damping due to aerodynamic drag is a nonlinear function of velocity. Damping due to crown contact has been suggested by a previous author to be a function of both the distance to and the size of adjacent trees. Therefore, in uniformly spaced stands it may be possible to model crown contact damping as a function of stand density index (SDI), a common forestry measure which incorporates both of these variables.

show abstract

An experimental investigation of the effects of dynamic loading on coniferous trees planted on wet mineral soils

Cited by 17 publications

References 0 publications

Root anchorage of hinoki (Chamaecyparis obtuse (Sieb. Et Zucc.) Endl.) under the combined loading of wind and rapidly supplied water on soil: analyses based on tree-pulling experiments

Root anchorage of hinoki (Chamaecyparis obtuse (Sieb. Et Zucc.) Endl.) under the combined loading of wind and rapidly supplied water on soil: analyses based on tree-pulling experiments

Vulnerability of spruce (Picea abies) and beech (Fagus sylvatica) forest stands to storms and consequences for silviculture

Natural sway frequencies and damping ratios of trees: concepts, review and synthesis of previous studies

Contact Info

Product

Resources

About