Untersuchungen über die Windverbreitung der Früchte und Samen mitteleuropäischer Waldbäume

Kohlermann, L.

doi:10.1007/bf01815738

Cited by 34 publications

(25 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…57). According to Kohlermann (1950), under conditions of open space at wind speed 1.7, 2.7 and 5.9 m s -1 seeds of Abies alba Mill. dropped from a height of 14 m covered 26, 34 and 72 m, on average, respectively.…”

Section: Characteristics Of Species and Study Sitesmentioning

confidence: 99%

“…Prior investigations have most often analysed the seed shadows of single trees (Kohlermann 1950;Greene and Johnson 1989;Guevara and Laborde 1993;Holthuijzen and Sharik 1985) or seed rain in border zones between closed stands and open/clear-cut areas (Greene and Johnson 1996;Dohrenbusch 1997;Johnson 1988). This, perhaps most general, knowledge is helpful overall for anemochoric species, which are mostly regenerated on larger open areas.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ground seed density patterns under conditions of strongly overlapping seed shadows in Abies alba Mill. stands

Paluch¹

2011

Eur J Forest Res

View full text Add to dashboard Cite

In three subsequent years, seeds were collected from 66 to 75 seed traps in three Abies alba stands that differed in vertical structure and the number of potentially reproducing trees. The objective was to compare empirical patterns of seed density with a random (Poisson) model, which assumes that seed density would be the same in every location, and a binomial negative model that is appropriate for over-dispersed data. The seed density patterns were tested for spatio-temporal independence. The effect of some dispersal variables (number of mother trees and seed fall seasons, dispersal distance, fecundity rate) on seed density pattern was studied in a simple simulation experiment. Several local stand density measures (stem density, basal area, distance-weighted indices, canopy openness) were also tested for their ability to predict local seed density. The Poisson model was rejected in all the stands studied, and a much better fit achieved using the binomial negative model. The simulation study revealed that random seed distribution may occur only at considerable dispersal distances, concave seed shadows, and at very low fecundity rates. The seed density patterns identified exhibited both spatial and temporal correlation, which can probably be linked to the arrangement of mother trees and variation in their seed output. To a minor degree, this seed density pattern also correlated with local stand density.

show abstract

Section: Characteristics Of Species and Study Sitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ground seed density patterns under conditions of strongly overlapping seed shadows in Abies alba Mill. stands

Paluch¹

2011

Eur J Forest Res

View full text Add to dashboard Cite

show abstract

“…Ignoring these four specimens (and their associated white ash distances), the calculated slope (with the intercept forced to pass through the origin) for 43 pairs is 1.78, whereas [ l ] predicted a slope of 1.77. Thus, Kohlermann (1950) for releases from a tower in an open field where . i is the mean distance traveled by a population, h, is the release height (constant at 14 m), u is the mean horizontal wind velocity, and v, is the mean terminal velocity.…”

Section: Resultsmentioning

confidence: 99%

“…The second test of the McCutchen-Green hypothesis relied on data collected by Kohlermann (1950). She conducted a series of simultaneous releases of eight species (including one bilaterally symmetric species, Fraxinus excelsior L.) over the range 1.7 5 ti 5 5.9 m/s.…”

Section: Methodsmentioning

confidence: 99%

“…It has been shown that such models provide reasonably accurate estimations of observed dispersal curves for experimental releases of glass microspheres or seeds from an elevated point source (Walker 1965;Stewart 1968; Greene and ~o h n s o n 1989). The range of mean terminal velocities (v,) for the microsphere populations used in these studies is similar to the range of v, for most species with plumed or winged seeds and fruits (0.15 5 vf 5 2.0 m/s; data in Kohlermann 1950, Sheldon and Burrows 1973, Augspurger 1986, and Matlack 1987.…”

Section: Introductionmentioning

confidence: 93%

See 1 more Smart Citation

The dispersal of winged fruits and seeds differing in autorotative behaviour

Greene¹,

Johnson²

1990

Can. J. Bot.

View full text Add to dashboard Cite

1990. The dispersal of winged fruits and seeds differing in autorotative behaviour.Can. J. Bot. 68: 2693-2697. The application of micrometeorological models of heavy particle dispersal to winged diaspores (samaras) requires that the diaspores maintain stable flight and that descent velocity is constant with respect to vertical air motion. Others have argued that these assumptions may be invalid for autorotating samaras and that bilaterally symmetric samaras will disperse farther than asymmetric samaras in conditions of large horizontal wind velocities (and (or) high turbulence) because the asymmetric morphology is inherently less stable in flight. Therefore, application of these models may not be appropriate for asymmetric samaras. Experimental and natural releases of asymmetric and symmetric samaras reported here indicate that the two samara morphologies respond similarly to a given flow regime. Thus, in modelling dispersal, the autorotation of the samaras can be ignored, and the samaras can be regarded as heavy particles descending at a constant rate from source to deposition site. . 1990. The dispersal of winged fruits and seeds differing in autorotative behaviour. Can.J. Bot. 68 : 2693-2697.L'application des modkles micromCtkorologiques pour la dispersion des particules lourdes aux diaspores ailees implique que les diaspores maintiennent un vol stable et que la vitesse de descente soit constante relativement au mouvement vertical de I'air. Certains auteurs ont avanck que ces assomptions pourraient ne pas Ctre valides pour les samares montrant une autorotation et que les samares a symktrie bilatCrale se disperseraient plus loin que les samares asymktriques, sous des conditions de vents horizontaux i forte vklocitk (et (ou) de forte turbulence), parce que la morphologie asymktrique, de faqon inhkrente, est moins stable en cours de vol. Ceci suggkre que I'application de ces modeles ne serait pas appropriie pour les samares asymktriques. Les rksultats de relichements expirimentaux ou naturels de samares symCtriques et asymktriques obtenus et prCsentks ici indiquent que les deux formes de samare rkagissent de la mCme faqon a un m&me rkgime d'kcoulement de I'air. ConsCquemment, on pest ignorer I'autorotation des samares dans la modklisation de la dispersion, et on peut considkrer les samares comme des particules lourdes descendant a une vitesse constante, de l'origine jusqu'au point d'arrivke.

show abstract