Examining conifer canopy structural complexity across forest ages and elevations with LiDAR data

LiDAR measurements of canopy structure can be used to classify forest stands into structural stages to study spatial patterns of canopy structure, identify habitat, or plan management actions. A key assumption in this process is that differences in canopy structure based on forest age and elevation are consistent with predictions from models of stand development. Three LiDAR metrics (95th percentile height, rumple, and canopy density) were computed for 59 secondary and 35 primary forest plots in the Pacific Northwest, USA. Hierarchical clustering identified two precanopy closure classes, two low-complexity postcanopy closure classes, and four high-complexity postcanopy closure classes. Forest development models suggest that secondary plots should be characterized by low-complexity classes and primary plots characterized by high-complexity classes. While the most and least complex classes largely confirmed this relationship, intermediate-complexity classes were unexpectedly composed of both secondary and primary forest types. Complexity classes were not associated with elevation, except that primary Tsuga mertensiana (Bong.) Carrière (mountain hemlock) plots were complex. These results suggest that canopy structure does not develop in a linear fashion and emphasize the importance of measuring structural conditions rather than relying on development models to estimate structural complexity across forested landscapes.

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Airborne laser altimetry and interferometric SAR measurements of canopy structure and sub-canopy topography in the Pacific northwest

Conference Proceedings Second Topical Symposium on Combined Optical-Microwave Earth and Atmosphere Sensing ◽

10.1109/comeas.1995.472395 ◽

2002 ◽

Cited By ~ 3

Author(s):

D.J. Harding ◽

J.B. Blair ◽

E. Rodriguez ◽

T. Michel

Keyword(s):

Pacific Northwest ◽

Canopy Structure ◽

Laser Altimetry ◽

Airborne Laser ◽

The Pacific ◽

Interferometric Sar

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Odor mixture perception: can molecular complexity be a factor determining elemental or configural perception?

10.1101/2020.05.27.120154 ◽

2020 ◽

Author(s):

Masayuki Hamakawa ◽

Hiroya Ishikawa ◽

Yumika Kikuchi ◽

Kaori Tamura ◽

Tsuyoshi Okamoto

Keyword(s):

Principal Component Analysis ◽

Structural Complexity ◽

Principal Component ◽

Low Complexity ◽

Olfactory Perception ◽

High Complexity ◽

Odor Mixture ◽

Individual Odor ◽

Odor Mixtures ◽

Molecular Complexity

AbstractOdor mixtures can evoke smells that differ from those of their individual odor components. Research has revealed the existence of two perceptual modes, in which a mixture can be perceived as either the original smells of its individual components (elemental) or as a novel smell (configural). However, the factors underlying the perceptual transformation that occurs when smelling a mixture versus its original components remain unclear. Therefore, the present study aimed to identify the properties of odorants that affect olfactory perception of odor mixtures, focusing on the structural complexity of an odorant. We conducted psychophysical experiments in which different groups of participants were instructed to provide olfactory perceptual descriptions of low-, medium-, and high-complexity odor mixtures or components, respectively. To investigate the perceptual modes induced by the mixtures, we compared the participants’ evaluations between mixtures and components via two types of analyses. First, we compared each olfactory description following quantification via principal component analysis. We then compared data based on seven major olfactory perceptual groups. We observed that odor mixtures composed of low-complexity odorants were perceived as relatively novel smells with regard to both minor (olfactory descriptions) and major (perceptual community) odor qualities than medium- and high-complexity mixtures. Such information may further our understanding of the olfactory perceptual modes of odor mixtures.

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