Biomass Data from Sector Subsampling of 360˚ Spherical Images
The base data were collected from 3 early spacing trials located in western Newfoundland, Canada (Cormack, Pasadena, Roddickton) and established in the early 1980s (Donnelly et al. 1986; Fig.1). All trees 1.3 m and taller were identified by species and measured for diameter at breast height and tota...
| Main Authors: | , |
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| Format: | Dataset |
| Language: | unknown |
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UNB
2021
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| Online Access: | https://dx.doi.org/10.25545/vcveh1 https://dataverse.lib.unb.ca/citation?persistentId=doi:10.25545/VCVEH1 |
| Summary: | The base data were collected from 3 early spacing trials located in western Newfoundland, Canada (Cormack, Pasadena, Roddickton) and established in the early 1980s (Donnelly et al. 1986; Fig.1). All trees 1.3 m and taller were identified by species and measured for diameter at breast height and total height periodically since the time of treatment. Using the most recent measurement at each trial, stemwood, bark, branch, and foliage biomass (kg) was estimated for each tree using the Canadian national biomass equations. Total above-ground biomass was estimated by summing these components. Total basal area was estimated by calculating tree cross-sectional area, multiplying by the appropriate plot expansion factor, and summing across all live trees. Spherical photos were obtained at three photo sample points located at half the plot radius and at azimuths of 0˚, 120˚, and 240˚. Spherical photos were obtained a 1.6m and 2.6m above the ground. Photo horizontal point sampling (Wang et al. 2020) using a 2 M photo basal angle gauge was used to estimate basal area at each sample point using the 1.6m spherical photo. Sector subsampling was then used to select measure trees using a randomly generated sector azimuth and a sector angle of 7.2˚ (2% of 360˚). All visible trees within each sector were then measured for total height and diameter at breast height using the spherical stereographic techniques. Biomass was then estimated using the Canadian National Biomass Equations, assuming all sector-selected trees were balsam fir. The plot-level data and measure-tree data were used to estimate aboveground biomass (BM, tonnes∙ha-1) using simulated resampling of the photo sample point data and ratio estimation. |
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