Measure of simultaneous tree sways and estimation of crown interactions among a group of trees

Rudnicki, Mark; Silins, U.; Lieffers, Victor J.; Josi, Georg

doi:10.1007/s004680000080

Cited by 69 publications

(48 citation statements)

References 29 publications

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“…Biaxial clinometers are gravity referenced, have a resonant frequency of 10 Hz and, with a range of ±10°and a resolution of 0.01°arc, they measure the ideal range of bending rotation for calculating sway displacement when mounted in the top third of a tree (Rudnicki et al 2001). A Wind Monitor (R.M.…”

Section: Methodsmentioning

confidence: 99%

The periodic motion of lodgepole pine trees as affected by collisions with neighbors

Rudnicki

Meyer

Lieffers

et al. 2008

Trees

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The periodic sways of a group of ten Pinus contorta var. latifolia (lodgepole pine) trees with slender stems from the Two Creeks site (TW) and ten stout trees from the Chickadee site (CH) both in Alberta, Canada were quantified. Tree displacement at TW was measured during periods of consistent wind direction with three mean wind speeds (1.9, 4.6, and 5.4 m/s) and for two mean wind speeds at CH (5.0 and 7.9 m/s). Spectral analysis of sway displacement data showed a decrease in the frequency with wind speed for trees at TW, but remained unchanged for trees at CH. Significant correlations between tree sway frequency and amplitude during high winds at TW indicate a loss of sway energy concomitant with the occurrence of high collision intensity. These observations support the hypothesis that inter-crown collisions have an important influence on the sway frequency of trees and should be incorporated into efforts to model their sway dynamics. We also present a theoretical collision-damped sway model which supports our empirical findings.

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Section: Methodsmentioning

confidence: 99%

The periodic motion of lodgepole pine trees as affected by collisions with neighbors

Rudnicki

Meyer

Lieffers

et al. 2008

Trees

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“…Crown Delineator could serve in other types of light analyses such as the study of light harvest of scattered trees in open agroforestry systems (Montero et al 2008) or for studying crown shyness (Meng et al 2006;Rudnicki et al 2001). For example, Rudnicki et al (2001) used a GIS program to study crown collisions caused by wind.…”

Section: Other Possible Uses For Crown Delineatormentioning

confidence: 99%

“…For example, Rudnicki et al (2001) used a GIS program to study crown collisions caused by wind. The shape files of crowns created by Crown Delineator could be incorporated in a GIS program to perform this type of analysis using actual crown shapes photographed in the stand.…”

Section: Other Possible Uses For Crown Delineatormentioning

confidence: 99%

A fast and reliable method for the delineation of tree crown outlines for the computation of crown openness values and other crown parameters

et al. 2011

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Numerous crown parameters (e.g., leaf area index, diameter, height, volume) can be obtained via the analysis of tree crown photographs. In all cases, parameter values are functions of the position of the crown outline. However, no standardized method to delineate crowns exists. To explore the effect of different outlines on tree crown descriptors, in this case crown openness (CO), and facilitate the adoption of a standard method free of user bias, we developed the program Crown Delineator that automatically delineates any outline around tree crowns following predetermined sensibility settings. We used different outlines to analyze tree CO in contrasting settings: using saplings from four species in young boreal mixedwood forests and medium-sized hybrid poplar trees from a low-density plantation. In both cases, the estimated CO increases when calculated from a looser outline, which had a strong influence on understory available light simulations using a forest simulator. These results demonstrate that the method used to trace crown outlines is an important step in the determination of CO values. We provide a much-needed computer-assisted solution to help standardize this procedure, which can also be used in many other situations in which the delineation of tree crowns is needed (e.g., competition and crown shyness).Résumé : Plusieurs paramètres de la cime, comme l'indice de surface foliaire, le diamètre, la hauteur et le volume, peuvent être obtenus par l'analyse de photographies de la cime des arbres. Dans tous les cas, la valeur des paramètres est fonction de la position du contour de la cime. Cependant, il n'existe pas de méthode standard pour délimiter la cime. Afin d'explorer l'effet de différents contours sur les descripteurs de la cime des arbres, l'ouverture de la cime dans ce cas-ci, et de faciliter l'adoption d'une méthode standard exempte de biais introduit par l'utilisateur, nous avons développé un programme, le déli-néateur de cime, qui délimite automatiquement n'importe quel contour de la cime des arbres selon des paramètres de sensibilité prédéterminés. Nous avons utilisé différents contours pour analyser l'ouverture de la cime en fonction de différents paramètres en ayant recours à des gaules de quatre espèces dans de jeunes forêts boréales mélangées et à des tiges de peuplier hybride de dimension intermédiaire provenant d'une plantation à faible densité. Dans les deux cas, l'ouverture de la cime estimée augmente lorsqu'elle est calculée à partir d'un contour plus approximatif, ce qui avait une forte influence sur les simulations de disponibilité de la lumière en sous-étage effectuées à l'aide d'un simulateur de forêt. Ces résultats démon-trent que la méthode utilisée pour tracer le contour des cimes est une étape importante dans la détermination de la valeur d'ouverture des cimes. Nous offrons une solution fort utile et assistée par ordinateur pour aider à standardiser cette procé-dure qui peut aussi être utilisée dans plusieurs autres situations où la délimitation de la cime des arbres...

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“…The degree of slenderness is an excellent indicator of its long-term exposure to pre-harvest wind (Rudnicki et al, 2001), as well as in plantations the tree responds with a dynamic pattern, such as a pole or chimney, cylindrical shape, before first roughing. Seben et al (2013) noted that a degree of slenderness above 100 generally indicates low stability and the tree may buckle on its own weight, while values below 80 indicate excellent stability.…”

Section: Discussionmentioning

confidence: 99%

Morphometric Relationships as Indicative of Silvicultural Interventions for Brazilian Pine in Southern Brazil

Hess¹,

Loiola²,

Minatti³

et al. 2018

JAS

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Silvicultural interventions are necessary to control the competition and to maintain the forest structure. Thus, this work aimed to know the interactions between dendro/morphometric variables to indicate density interventions in Brazilian pine Forest. Dendrometric and morphometric variables were measured from 186 individual trees of this species, which were distributed in diametric classes at three sites. With the variables were fitted models for the relationships between the degree of slenderness and the potential crown diameter as a function of the number of trees per hectare. The fit indicated that the variables showed interaction and the relationship can be described by linear function explaining between 51.9 and 99.3% of the variance between morphometry and forest density. This adjustment and information can be used to indicate the optimum density according to the amplitude of each index. The results show that the morphometric indexes and their interaction indicate the period of the interventions, having relation with the characteristics of the site, the diametric structure and the dynamics of the forest growth.

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Measure of simultaneous tree sways and estimation of crown interactions among a group of trees

Cited by 69 publications

References 29 publications

The periodic motion of lodgepole pine trees as affected by collisions with neighbors

The periodic motion of lodgepole pine trees as affected by collisions with neighbors

A fast and reliable method for the delineation of tree crown outlines for the computation of crown openness values and other crown parameters

Morphometric Relationships as Indicative of Silvicultural Interventions for Brazilian Pine in Southern Brazil

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