scholarly journals Individual Tree Detection from Unmanned Aerial Vehicle (UAV) Derived Canopy Height Model in an Open Canopy Mixed Conifer Forest

Forests ◽  
2017 ◽  
Vol 8 (9) ◽  
pp. 340 ◽  
Author(s):  
Midhun Mohan ◽  
Carlos Silva ◽  
Carine Klauberg ◽  
Prahlad Jat ◽  
Glenn Catts ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Individual Tree ◽  
Tree Detection ◽  
Mixed Conifer Forest ◽  
Open Canopy ◽  
Aerial Vehicle ◽  
Canopy Height Model ◽  
Height Model

scholarly journals Comparison and Evaluation of Different Pit-Filling Methods for Generating High Resolution Canopy Height Model Using UAV Laser Scanning Data

2021 ◽  
Vol 13 (12) ◽  
pp. 2239
Author(s):  
Ying Quan ◽  
Mingze Li ◽  
Yuanshuo Hao ◽  
Bin Wang
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Evaluation Framework ◽  
Canopy Height ◽  
Filter Method ◽  
Individual Tree ◽  
Significant Difference ◽  
Point Interpolation ◽  
Canopy Height Model ◽  
Height Model

As a common form of light detection and ranging (LiDAR) in forestry applications, the canopy height model (CHM) provides the elevation distribution of aboveground vegetation. A CHM is traditionally generated by interpolating all the first LiDAR echoes. However, the first echo cannot accurately represent the canopy surface, and the resulting large amount of noise (data pits) also reduce the CHM quality. Although previous studies concentrate on many pit-filling methods, the applicability of these methods in high-resolution unmanned aerial vehicle laser scanning (UAVLS)-derived CHMs has not been revealed. This study selected eight widely used, recently developed, representative pit-filling methods, namely first-echo interpolation, smooth filtering (mean, medium and Gaussian), highest point interpolation, pit-free algorithm, spike-free algorithm and graph-based progressive morphological filtering (GPMF). A comprehensive evaluation framework was implemented, including a quantitative evaluation using simulation data and an additional application evaluation using UAVLS data. The results indicated that the spike-free algorithm and GPMF had excellent visual performances and were closest to the real canopy surface (root mean square error (RMSE) of simulated data were 0.1578 m and 0.1093 m, respectively; RMSE of UAVLS data were 0.3179 m and 0.4379 m, respectively). Compared with the first-echo method, the accuracies of the spike-free algorithm and GPMF improved by approximately 23% and 22%, respectively. The pit-free algorithm and highest point interpolation method also have advantages in high-resolution CHM generation. The global smooth filter method based on the first-echo CHM reduced the average canopy height by approximately 7.73%. Coniferous forests require more pit-filling than broad-leaved forests and mixed forests. Although the results of individual tree applications indicated that there was no significant difference between these methods except the median filter method, pit-filling is still of great significance for generating high-resolution CHMs. This study provides guidance for using high-resolution UAVLS in forestry applications.

Spatial variability in microclimate in a mixed-conifer forest before and after thinning and burning treatments

2010 ◽  
Vol 259 (5) ◽  
pp. 904-915 ◽  
Author(s):  
Siyan Ma ◽  
Amy Concilio ◽  
Brian Oakley ◽  
Malcolm North ◽  
Jiquan Chen
Keyword(s):  
Spatial Variability ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Mixed Conifer Forest ◽  
Before And After

Development of the mixed conifer forest in northern New Mexico and its relationship to Holocene environmental change

2008 ◽  
Vol 69 (2) ◽  
pp. 263-275 ◽  
Author(s):  
R. Scott Anderson ◽  
Renata B. Jass ◽  
Jaime L. Toney ◽  
Craig D. Allen ◽  
Luz M. Cisneros-Dozal ◽  
...  
Keyword(s):  
New Mexico ◽  
Pinus Ponderosa ◽  
Late Glacial ◽  
Conifer Forest ◽  
Lake Levels ◽  
Mixed Conifer ◽  
The Holocene ◽  
Groundwater Levels ◽  
Mixed Conifer Forest ◽  
Jemez Mountains

Chihuahueños Bog (2925 m) in the Jemez Mountains of northern New Mexico contains one of the few records of late-glacial and postglacial development of the mixed conifer forest in southwestern North America. The Chihuahueños Bog record extends to over 15,000 cal yr BP. AnArtemisiasteppe, then an openPiceawoodland grew around a small pond until ca. 11,700 cal yr BP whenPinus ponderosabecame established. C/N ratios,δ13C andδ15N values indicate both terrestrial and aquatic organic matter was incorporated into the sediment. Higher percentages of aquatic algae and elevated C/N ratios indicate higher lake levels at the opening of the Holocene, but a wetland developed subsequently as climate warmed. From ca. 8500 to 6400 cal yr BP the pond desiccated in what must have been the driest period of the Holocene there. C/N ratios declined to their lowest Holocene levels, indicating intense decomposition in the sediment. Wetter conditions returned after 6400 cal yr BP, with conversion of the site to a sedge bog as groundwater levels rose. Higher charcoal influx rates after 6400 cal yr BP probably result from greater biomass production rates. Only minor shifts in the overstory species occurred during the Holocene, suggesting that mixed conifer forest dominated throughout the record.

scholarly journals Changes in Nitrogen-Fixing and Ammonia-Oxidizing Bacterial Communities in Soil of a Mixed Conifer Forest after Wildfire

2005 ◽  
Vol 71 (5) ◽  
pp. 2713-2722 ◽  
Author(s):  
Chris M. Yeager ◽  
Diana E. Northup ◽  
Christy C. Grow ◽  
Susan M. Barns ◽  
Cheryl R. Kuske
Keyword(s):  
Bacterial Communities ◽  
Fragment Length Polymorphism ◽  
Rflp Analysis ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrogen Fixing ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Mixed Conifer Forest ◽  
In Fire ◽  
Sequence Types

ABSTRACT This study was undertaken to examine the effects of forest fire on two important groups of N-cycling bacteria in soil, the nitrogen-fixing and ammonia-oxidizing bacteria. Sequence and terminal restriction fragment length polymorphism (T-RFLP) analysis of nifH and amoA PCR amplicons was performed on DNA samples from unburned, moderately burned, and severely burned soils of a mixed conifer forest. PCR results indicated that the soil biomass and proportion of nitrogen-fixing and ammonia-oxidizing species was less in soil from the fire-impacted sites than from the unburned sites. The number of dominant nifH sequence types was greater in fire-impacted soils, and nifH sequences that were most closely related to those from the spore-forming taxa Clostridium and Paenibacillus were more abundant in the burned soils. In T-RFLP patterns of the ammonia-oxidizing community, terminal restriction fragments (TRFs) representing amoA cluster 1, 2, or 4 Nitrosospira spp. were dominant (80 to 90%) in unburned soils, while TRFs representing amoA cluster 3A Nitrosospira spp. dominated (65 to 95%) in fire-impacted soils. The dominance of amoA cluster 3A Nitrosospira spp. sequence types was positively correlated with soil pH (5.6 to 7.5) and NH3-N levels (0.002 to 0.976 ppm), both of which were higher in burned soils. The decreased microbial biomass and shift in nitrogen-fixing and ammonia-oxidizing communities were still evident in fire-impacted soils collected 14 months after the fire.

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