To understand the social, political, economic, and ecological implications of historic land use patterns of Caracol, one of the largest (~200 sq km) Maya archaeological sites, we are conducting a regional survey using satellite and airborne sensors. About one-fifth of this polity has been mapped with traditional ground-based methods. In this NASA-funded project, we acquired Landsat TM/ETM, IKON...

Monitoring current forest characteristics in the taiga ́tundra ecotone (TTE) at multiple scales is critical for understanding its vulnerability to structural changes. A 30 m spatial resolution Landsat-based tree canopy cover map has been calibrated and validated in the TTE with reference tree cover data from airborne LiDAR and high resolution spaceborne images across the full range of boreal for...

Coniferous forests represent canopies with a high heterogeneity in the horizontal and as well in the vertical dimension. Consequently the interaction of incident radiation is dominated by the complex 3-D canopy structure and architecture. Radiative transfer approaches based on coupled leaf and canopy radiative transfer models (RTM) still allow the simulation of the multidirectional canopy refle...

Objectives: Despite the substantial loss of natural forest in the Bosomkese Forest Reserve, little is known on the effects of the massive habitat loss and degradation on forest biota. The study therefore assessed the effects of anthropogenic activities on butterfly species composition and abundance in the Bosomkese Forest reserve in the Brong Ahafo region of Ghana. Methodology and Results: The ...

The remaining native forests on the Hawaiian Islands have been recognized as threatened by changing climate, increasing insect outbreak, new deadly pathogens, and growing populations of canopy structure-altering invasive species. The objective of this study was to assess long-term, net changes to upper canopy structure in sub-montane forests on the eastern slope of Mauna Kea volcano, Hawai'i, i...

The currently prevailing view is that saplings require gaps or larger disturbances in order to grow into the canopy. This study documents an exception. In California's Pseudotsuga-mixed hardwood forests, crowns of Pseudotsuga menziesii (Douglas fir) are within those of angiosperm trees (Arbutus menziesii and Quercus species). In the forests we examined, every Pseudotsuga was younger and all but...

McIntosh, Anne C.S.; Gray, Andrew N.; Garman, Steven L. 2009. Canopy structure on forest lands in western Oregon: differences among forest types and stand ages. Gen. Tech. Rep. PNW-GTR-794. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 35 p. Canopy structure is an important attribute affecting economic and ecological values of forests in the P...

Ground penetrating radar (GPR) with a suspended 1 GHz horn antenna was deployed for measurement of soil water contents and dwatj wheat canopy reflections over bare and electrically terminating sutjaces. Sutjace reflection (SR) magnitudes and propagation times (PI) were used to independently calculate bulk soil dielectric constant and soil water contents. Measurements over wheat canopy shows tha...

Waveform light detection and ranging (wLiDAR) records the entire backscattered signal of an emitted laser pulse, enabling deeper penetration through tree canopy. However, due to interactions (e.g. reflection, absorption, and transmission) within the canopy, the full proportion of emitted light may not reach the ground, resulting in an attenuated waveform. Correction of attenuation will result i...

Vegetation indices (VIs) are among the oldest tools in remote sensing studies. Although many variations exist, most of them ratio the reflection of light in the red and NIR sections of the spectrum to separate the landscape into water, soil, and vegetation. Theoretical analyses and field studies have shown that VIs are near-linearly related to photosynthetically active radiation absorbed by a p...