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Abstract Forests sequester a substantial portion of anthropogenic carbon emissions. Many open questions concern how. We address two of these questions. Has leaf and fine litter production changed? And what is the contribution of old‐growth forests? We address these questions with long‐term records (≥10 years) of total, reproductive, and especially foliar fine litter production from 32 old‐growth forests. We expect increases in forest productivity associated with rising atmospheric carbon dioxide concentrations and, in cold climates, with rising temperatures. We evaluate the statistical power of our analysis using simulations of known temporal trends parameterized with sample sizes (in number of years) and levels of interannual variation observed for each record. Statistical power is inadequate to detect biologically plausible trends for records lasting less than 20 years. Modest interannual variation characterizes fine litter production, and more variable phenomena will require even longer records to evaluate global change responses with sufficient statistical power. Just four old‐growth forests have records of fine litter production lasting longer than 20 years, and these four provide no evidence for increases. Three of the four forests are in central Panama, also have long‐term records of wood production, and both components of aboveground production are unchanged over 21–38 years. The possibility that recent increases in forest productivity are limited for old‐growth forests deserves more attention. 

The Barro Colorado Nature Monument in Panama, which includes Barro Colorado Island and nearby mainland peninsulas, supports the best studied tropical forest in the world. This 98-chapter edited volume reviews the history and contributions of research undertaken at this moist tropical forest to advance our understanding of tropical plants and ecosystems. The first section describes the setting, including soils, land use history, forest structure, and plant species composition. Nine additional sections concern plant reproduction and seedling regeneration, plant physiology, plant community ecology, population genetics, interactions with microbes and herbivores, remote sensing, observational ecosystem studies, experimental ecosystem studies, and focal taxa and functional group accounts. The authoritative reviews in this volume provide a foundation for future research in this and other tropical forest sites. 

We provide data on mean dry and wet mass of > 800 species from Yasuní National Forest, Ecuador collected between 2000 and 2014. Species include trees, shrubs, lianas and herbs. We also provide data on number of seeds per fruit for >1100 species compiled in 2016, along with information on fruit type and dispersal mode. Both of these data sets supplement previously published data on flowering and fruiting phenology from this equatorial, ever-wet rainforest in eastern Ecuador (Garwood et al. 2023). Garwood, N.C., S.J. Wright, R. Valencia, and M.R. Metz. 2023. Rainforest phenology: flower, fruit and seed production from biweekly collections of 200 traps in the Yasuní Forest Dynamics Plot, Ecuador, 2000-2018 ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/5e6cb3d7ff741fd9d21965c4a904bc1f (Accessed 2024-03-27). 

Fine roots are key to ecosystem-scale nutrient, carbon (C), and water cycling, yet our understanding of fine root trait variation within and among tropical forests, one of Earth’s most C-rich ecosystems, is limited. We characterized root biomass, morphology, nutrient content, and arbuscular mycorrhizal fungal (AMF) colonization to 1.2 m depths across four distinct lowland Panamanian forests, and related root characteristics to soil C stocks. We hypothesized that: (H1) Fine root characteristics vary consistently with depth across seasonal tropical forests, with deeper roots exhibiting more exploratory traits, such as for deep water acquisition; (H2) fine root characteristics vary among tropical forests mainly in surface soils, where resource availability also varies. We found consistent variation with depth across the four forests, including decreased root biomass, root tissue density, and AMF, and increased specific root length. Among the forests, there was variation in some fine root characteristics, including greater surface root biomass and lower SRL in the wettest forest, and smaller fine root diameter in the driest forest. We also found that root characteristics were related to total soil C stocks, which were positively related to root biomass and negatively related to specific root length. These results indicate emergent properties of root variation with depth across tropical forests, and show site-scale variation in surface root characteristics. Future work could explore the flexibility in root characteristics under changing conditions such as drought. 

Forests sequester a substantial portion of anthropogenic carbon emissions. Many open questions concern how. We address two of these questions. Has leaf and fine litter production changed? And what is the contribution of old-growth forests? We address these questions with long-term records (≥10 years) of total, reproductive, and especially foliar fine litter production from 32 old-growth forests. We expect increases in forest productivity associated with rising atmospheric carbon dioxide concentrations and, in cold climates, with rising temperatures. We evaluate the statistical power of our analysis using simulations of known temporal trends parameterized with sample sizes (number of years) and levels of interannual variation observed for each record. Statistical power is inadequate to detect biologically plausible trends for records lasting less than 20 years. Modest interannual variation characterizes fine litter production. More variable phenomena will require even longer records to evaluate global change responses with sufficient statistical power.  Just four old-growth forests have records of fine litter production lasting longer than 20 years, and these four provide no evidence for increases. Three of the four forests are in central Panama, also have long-term records of wood production, and both components of aboveground production are unchanged over 21 to 38 years. The possibility that recent increases in forest productivity are limited for old-growth forests deserves more attention. This data package contains previously unpublished data from four old-growth forests in central Panama. Data compiled from the published literature for another 28 forests and the R scripts required to recreate our analyses can be found here: https://smithsonian.dataone.org/view/urn:uuid:8bbcd334-059b-45b1-9b83-94b52abbd6f8. 

Forests sequester a substantial portion of anthropogenic carbon emissions. Many open questions concern how. We address two of these questions (Wright and Calderón 2025). Has leaf and fine litter production changed? And what is the contribution of old-growth forests? We address these questions with long-term records (≥10 years) of total, reproductive, and especially foliar fine litter production from 32 old-growth forests. We expect increases in forest productivity associated with rising atmospheric carbon dioxide concentrations and, in cold climates, with rising temperatures. We evaluate the statistical power of our analysis using simulations of known temporal trends parameterized with sample sizes (number of years) and levels of interannual variation observed for each record. Statistical power is inadequate to detect biologically plausible trends for records lasting less than 20 years. Just four old-growth forests have records of fine litter production lasting longer than 20 years, and these four provide no evidence for increases. Three of the four forests are in central Panama, also have long-term records of wood production, and both components of aboveground production are unchanged over 21 to 38 years. The possibility that recent increases in forest productivity are limited for old-growth forests deserves more attention. Modest interannual variation characterizes fine litter production, and more variable phenomena will require even longer records to evaluate global change responses with sufficient statistical power. The data files and R scripts in this data package recreate the analyses of Wright and Calderón (2025). References Wright, S. J. and O. Calderón. 2025. Statistical power and the detection of global change responses: The case of leaf production in old-growth forests. Ecology (accepted 28 October 2024; manuscript ECY23-1254.R1) 

Abstract All species must partition resources among the processes that underly growth, survival, and reproduction. The resulting demographic trade‐offs constrain the range of viable life‐history strategies and are hypothesized to promote local coexistence. Tropical forests pose ideal systems to study demographic trade‐offs as they have a high diversity of coexisting tree species whose life‐history strategies tend to align along two orthogonal axes of variation: a growth–survival trade‐off that separates species with fast growth from species with high survival and a stature–recruitment trade‐off that separates species that achieve large stature from species with high recruitment. As these trade‐offs have typically been explored for trees ≥1 cm dbh, it is unclear how species' growth and survival during earliest seedling stages are related to the trade‐offs for trees ≥1 cm dbh. Here, we used principal components and correlation analyses to (1) determine the main demographic trade‐offs among seed‐to‐seedling transition rates and growth and survival rates from the seedling to overstory size classes of 1188 tree species from large‐scale forest dynamics plots in Panama, Puerto Rico, Ecuador, Taiwan, and Malaysia and (2) quantify the predictive power of maximum dbh, wood density, seed mass, and specific leaf area for species' position along these demographic trade‐off gradients. In four out of five forests, the growth–survival trade‐off was the most important demographic trade‐off and encompassed growth and survival of both seedlings and trees ≥1 cm dbh. The second most important trade‐off separated species with relatively fast growth and high survival at the seedling stage from species with relatively fast growth and high survival ≥1 cm dbh. The relationship between seed‐to‐seedling transition rates and these two trade‐off aces differed between sites. All four traits were significant predictors for species' position along the two trade‐off gradients, albeit with varying importance. We concluded that, after accounting for the species' position along the growth–survival trade‐off, tree species tend to trade off growth and survival at the seedling with later life stages. This ontogenetic trade‐off offers a mechanistic explanation for the stature–recruitment trade‐off that constitutes an additional ontogenetic dimension of life‐history variation in species‐rich ecosystems. 

Objectives:Fine roots significantly influence ecosystem-scale cycling of nutrients, carbon (C), and water, yet there is limited understanding of how fine root traits vary across and within tropical forests, some of Earth's most C-rich ecosystems. The biomass of fine roots can impact soil carbon storage, as root mortality is a primary source of new carbon to soils. A positive relationship has been observed between fine root biomass and soil carbon stocks in Panama (Cusack et al 2018). Beyond biomass, root characteristics like specific root length (SRL) could also influence soil carbon, as roots with higher SRL are less dense and thinner, potentially decomposing more easily or promoting soil aggregation. Understanding the effects of root morphology and tissue quality on soil carbon storage and with soil properties in general can improve predictions of landscape-scale carbon patterns. We aggregated new data of root biomass, morphology and nutrient content at 0-10 cm, 10-20 cm, 20-50 cm and 50-100 cm depth increments across four distinct lowland Panamanian forests and paired with already published datasets (Cusack et al 2018; Cusack and Turner 2020) of soil chemistry from the same sites and soil depths to explore relationship between soil carbon stocks and root characteristics.Datasets included:The datasets provided include .csv and .xlsx files for fine root characteristics and soil chemistry from four different forests across 0-10 cm, 10-20 cm, 20-50 cm, and 50-100 cm depth increments. Root characteristics include live fine root biomass, dead fine root biomass, coarse root biomass, specific root length, root diameter, root tissue density, specific root area, root %N, root %C, and root C/N ratio. Soil chemistry data includes total carbon (TC), dissolved organic carbon (DOC), bulk density, total phosphorus (TP), available phosphorus (AEM Pi), and various Mehlich-extractable elements such as aluminum, calcium, iron, potassium, manganese, phosphorus, and zinc. Nitrogen content measures include ammonium, nitrate, total dissolved nitrogen (TDN), dissolved inorganic nitrogen (DIN), and dissolved organic nitrogen (DON). The dataset also includes total exchangeable bases (TEB) and effective cation exchange capacity (ECEC) in both centimoles of charge per kilogram and micromoles of charge per gram. The soil chemistry data was obtained from Cusack et al (2018) and Cusack and Turner (2020) and paired with root characteristics data for the same depth increments and sites. Additionally, a .kml file is provided with coordinates for all 32 plots included in the study across four forests (n = 8 plots per site). Root data was averaged across these 8 plots per site and soil data was collected in one pit in each site. This dataset serves as baseline data before a throughfall exclusion experiment, Panama Rainforest Changes with Experimental Drying (PARCHED), was implemented. No special software is needed to open these files.