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Forest diversity is the outcome of multiple species-specific processes and tolerances, from regeneration, growth, competition and mortality of trees. Predicting diversity thus requires a comprehensive understanding of those processes. Regeneration processes have traditionally been overlooked, due to high stochasticity and assumptions that recruitment is not limiting for forests. Thus, we investigated the importance of seed production and seedling survival on forest diversity in the Pacific Northwest (PNW) using a forest gap model (ForClim). Equations for regeneration processes were fit to empirical data and added into the model, followed by simulations where regeneration processes and parameter values varied. Adding regeneration processes into ForClim improved the simulation of species composition, compared to Forest Inventory Analysis data. We also found that seed production was not as important as seedling survival, and the time it took for seedlings to grow into saplings was a critical recruitment parameter for accurately capturing tree species diversity in PNW forest stands. However, our simulations considered historical climate only. Due to the sensitivity of seed production and seedling survival to weather, future climate change may alter seed production or seedling survival and future climate change simulations should include these regeneration processes to predict future forest dynamics in the PNW. This article is part of the theme issue ‘Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere’.
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This content will become publicly available on November 22, 2025
Flower and Seed Production, Seedling Dynamics, and Tree Life Cycles
We present highlights derived from 36 years of weekly observations of flower and seed production and 25 years of annual observations of seedling dynamics at Barro Colorado Island (BCI), Panama. Highlights concern levels and causes of spatial, temporal, and interspecific variation in flower production, seed production, seed dispersal, and seedling recruitment, growth, and survival as well as the consequences for plant regeneration and diversity. Full tree life cycles are assembled by combining seed production, seedling dynamics, and observations of larger plants from the 50-ha Forest Dynamics Plot and are used to evaluate the costs of dioecy, lifetime insights from functional traits, and interspecific variation in the impact of lianas among host tree species. A variety of results demonstrate the importance of long-term observations to understand forest dynamics and responses to rising atmospheric carbon dioxide concentrations and a changing climate.
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- Award ID(s):
- 1754632
- PAR ID:
- 10618261
- Publisher / Repository:
- Smithsonian Institution Scholarly Press
- Date Published:
- ISSN:
- 978-1-944466-71-8
- ISBN:
- 978-1-944466-70-1
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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