Life Sciences Commons^™

Comparing Human Activity Density And Green Space Supply Using The Baidu Heat Map In Zhengzhou, China, Shumei Zhang, Wenshi Zhang, Ying Wang, Xiaoyu Zhao, Peihao Song, Guohang Tian, Audrey L. Mayer

Michigan Tech Publications

Rapidly growing cities often struggle with insufficient green space, although information on when and where more green space is needed can be difficult to collect. Big data on the density of individuals in cities collected from mobile phones can estimate the usage intensity of urban green space. Taking Zhengzhou's central city as an example, we combine the real-time human movement data provided by the Baidu Heat Map, which indicates the density of mobile phones, with vector overlays of different kinds of green space. We used the geographically weighted regression (GWR) method to estimate differentials in green space usage between weekdays …

Tree Species Richness Enhances Stand Productivity While Stand Structure Can Have Opposite Effects, Based On Forest Inventory Data From Germany And The United States Of America, Laura Zeller, Jingjing Liang, Hans Pretzsch

Faculty & Staff Scholarship

Background: In recent studies, mixed forests were found to be more productive than monocultures with everything else remaining the same.

Methods: To find out if this productivity is caused by tree species richness, by a more heterogeneous stand structure or both, we analyzed the effects of forest structure and tree species richness on stand productivity, based on inventory data of temperate forests in the United States of America and Germany.

Results: Having accounted for effects such as tree size and stand density, we found that: (I) tree species richness increased stand productivity in both countries while the effect of tree …

Remote Sensing Of Forests Using Discrete Return Airborne Lidar, Hamid Hamraz, Marco A. Contreras

Forestry and Natural Resources Faculty Publications

Airborne discrete return light detection and ranging (LiDAR) point clouds covering forested areas can be processed to segment individual trees and retrieve their morphological attributes. Segmenting individual trees in natural deciduous forests, however, remained a challenge because of the complex and multi-layered canopy. In this chapter, we present (i) a robust segmentation method that avoids a priori assumptions about the canopy structure, (ii) a vertical canopy stratification procedure that improves segmentation of understory trees, (iii) an occlusion model for estimating the point density of each canopy stratum, and (iv) a distributed computing approach for efficient processing at the forest level. …

Review Of Broad-Scale Drought Monitoring Of Forests: Toward An Integrated Data Mining Approach, Steven P. Norman, Frank H. Koch, William W. Hargrove

USDA Forest Service / UNL Faculty Publications

Efforts to monitor the broad-scale impacts of drought on forests often come up short. Drought is a direct stressor of forests as well as a driver of secondary disturbance agents, making a full accounting of drought impacts challenging. General impacts can be inferred from moisture deficits quantified using precipitation and temperature measurements. However, derived meteorological indices may not meaningfully capture drought impacts because drought responses can differ substantially among species, sites and regions. Meteorology-based approaches also require the characterization of current moisture conditions relative to some specified time and place, but defining baseline conditions over large, ecologically diverse regions can …