Measures of spatial forest structure derived from airborne laser data are associated with natural regeneration patterns in an uneven-aged spruce forest

Bollandsås, Ole Martin; Hanssen, Kjersti; Marthiniussen, Solfrid; Næsset, Erik

doi:10.1016/j.foreco.2007.10.017

Cited by 24 publications

(14 citation statements)

References 32 publications

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“…Since the downward facing part is larger than the upward facing, the effect of the transformation is greater for the downward facing part, resulting in reduced metric values. This finding concurs with Breidenbach et al [2], who stated that the height of ALS point clouds from trees growing on steep slopes would be overestimated because of the imbalance of crown size on upward and downward facing slopes. Because we applied the transformations on a plot level instead of a single tree level, this effect is reduced to the transformation of the crown of trees along the edge of the plots, leaving the trees in the middle of the plot less affected.…”

Section: Discussionsupporting

confidence: 92%

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Countering Negative Effects of Terrain Slope on Airborne Laser Scanner Data Using Procrustean Transformation and Histogram Matching

Hansen¹,

Ene²,

Gobakken³

et al. 2017

Forests

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Forest attributes such as tree heights, diameter distribution, volumes, and biomass can be modeled utilizing the relationship between remotely sensed metrics as predictor variables, and measurements of forest attributes on the ground. The quality of the models relies on the actual relationship between the forest attributes and the remotely sensed metrics. The processing of airborne laser scanning (ALS) point clouds acquired under heterogeneous terrain conditions introduces a distortion of the three-dimensional shape and structure of the ALS data for tree crowns and thus errors in the derived metrics. In the present study, Procrustean transformation and histogram matching were proposed as a means of countering the distortion of the ALS data. The transformations were tested on a dataset consisting of 192 field plots of 250 m 2 in size located on a gradient from gentle to steep terrain slopes in western Norway. Regression models with predictor variables derived from (1) Procrustean transformed-and (2) histogram matched point clouds were compared to models with variables derived from untransformed point clouds. Models for timber volume, basal area, dominant height, Lorey's mean height, basal area weighted mean diameter, and number of stems were assessed. The results indicate that both (1) Procrustean transformation and (2) histogram matching can be used to counter crown distortion in ALS point clouds. Furthermore, both techniques are simple and can easily be implemented in the traditional processing chain of ALS metrics extraction.

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Section: Discussionsupporting

confidence: 92%

“…Generally, these metrics can be described as "height" and "density" metrics providing proxies for the height and density of the forest canopy. For a more thorough description of the height and density metrics, see e.g., [2,3].…”

Section: Introductionmentioning

confidence: 99%

Countering Negative Effects of Terrain Slope on Airborne Laser Scanner Data Using Procrustean Transformation and Histogram Matching

Hansen¹,

Ene²,

Gobakken³

et al. 2017

Forests

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“…In addition, the intensity value which describes the amount of backscattering of the echo can be utilized. The height characteristics of ALS data have been used in various studies: When analyzing the modeled canopy fuel parameters of vertical forest structures for the purposes of fire behavior assessment [15,16], distinguishing dominant and understorey layers of vegetation [17][18][19], analysis of natural regeneration [20]. and to predict the characteristics of dead wood in a given sample area [21,22].…”

Section: Introductionmentioning

confidence: 99%

Airborne Laser Scanning for the Site Type Identification of Mature Boreal Forest Stands

et al. 2011

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Abstract:In Finland, forest site types are used to assess the need of silvicultural operations and the growth potential of the forests and, therefore, provide important inventory information. This study introduces airborne laser scanner (ALS) data and the k-NN classifier data analysis technique applicable to the site quality assessment of mature forests. Both the echo height and the intensity value percentiles of different echo types of ALS data were used in the analysis. The data are of 274 mature forest stands of different sizes, belonging to five forest site types, varying from very fertile to poor forests, in Koli National Park, eastern Finland. The k-NN classifier was applied with values of k varying from 1 to 5. The best overall classification accuracy achieved for all the forest site types and for a single type, were 58% and 73%, respectively. The conclusion is that when conducting large-scale forest inventories ALS-data based analysis would be a useful technology for the identification of mature boreal site types. However, the technique could still be improved and further studies are needed to ensure its applicability under different local conditions and with data representing earlier stages of stand development.

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“…Multilayer forests are formations of small-scale, continuous disturbances which promote regeneration in natural canopy openings by even forming the new tree generations (e.g. Zhu et al 2003, Bollandsås et al 2008. Furthermore, according to Spies and Franklin (1989) even shade-tolerant tree species require small canopy gaps to reach the canopy in old-growth forests, which indicates regeneration difficulties for shade-intolerant species.…”

Section: Canopy Gapsmentioning

confidence: 99%

Airborne laser scanning based identification and interpretation on ecologically important old-growth forest habitats in natural conservation areas

Vehmas¹

2011

Diss. For.

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Measures of spatial forest structure derived from airborne laser data are associated with natural regeneration patterns in an uneven-aged spruce forest

Cited by 24 publications

References 32 publications

Countering Negative Effects of Terrain Slope on Airborne Laser Scanner Data Using Procrustean Transformation and Histogram Matching

Countering Negative Effects of Terrain Slope on Airborne Laser Scanner Data Using Procrustean Transformation and Histogram Matching

Airborne Laser Scanning for the Site Type Identification of Mature Boreal Forest Stands

Airborne laser scanning based identification and interpretation on ecologically important old-growth forest habitats in natural conservation areas

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