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Marked individual northern red oak seedlings were individually marked and mapped at 20 valleywide transects starting in summer 2011. This data set includes detailed seedling measures starting in summer 2014. The data were used to examine the impact of previous year seedling condition on whether the seedling survived in the next season. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
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Hubbard Brook Experimental Forest: Oak seedling demography, 2011 - ongoing
This data set was built from a larger data set of marked northern red oak seedlings surveyed from 2011-2023. In this data set, only seedlings marked in their year of germination with full environmental and seedlings measures were kept (N = 937). The data set was built for an accelerated failure time model of seedling survival that found year of germination, seedling density, shrub cover and elevation to have the largest effect on survival time. The status of the seedling acorn (attached or missing) was also important. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
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- PAR ID:
- 10573257
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Marked seedlings. Our dataset includes 1463 marked individual oak seedlings in 535 5m2 plots over the 20 transects. Overall, oak seedlings occurred in a third of the searched plots. Most plots had only one seedling (236 plots) and only 3% (16 plots) of the plots had 10 or more seedlings, with a maximum density of 3.4 seedlings m2. Cohort years 2011, 2015, 2017 and 2022 had a greater influx of seedlings, and our oldest seedling is estimated to be 30 years or older. For seedlings where initial height was measured in their year of germination (i.e., in 2011 or later) mean initial seedling height was 14.8 cm (SD = 6.51 cm) and there was a small but significant decline in initial seedling height with time (-0.23 cm/year, F1,1298 = 19.97, p=<0.0001). The size of first year seedlings as measured by both initial height (F1,760 = 25.2, p<0.001) and leaf number (F1,752 = 11.1, p=0.009) increased on average with distance into the valley. The mean distance of oak seedlings into the valley has not increased over the course of the study and remains centered around 800m from the east entrance. Plot environment. Study transects encompassed a full range of topographic positions in the lower valley. Hemlock dominance ranged from absent (5 transects) to dominant (greater than 50% of trees; 3 transects). Tree basal area around the plots ranged from 18.8 – 43.5 m2 ha-1. Light transmission was universally low (all ≤13% TT). Light transmission (F1,5916 = 139.3; r2: 0.157, p<0.0001), hemlock dominance (F1,5916 = 2024; r2: 0.255, p<0.0001), and oak seedling density (F1,5916 = 73.9; r2: 0.126, p<0.0001) all decreased with distance further west into the valley. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.more » « less
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