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openCC (other)Jun 2025View details →

Long-term growth, mortality and regeneration of trees in permanent vegetation plots in the Pacific Northwest, 1910 to present

A network of more than 130 permanent vegetation plots provides long-term information on patterns and rates of forest succession in most of the major forest zones of the Pacific Northwest. The plot network extends from the coast to the Cascades in western Oregon and Washington and east to ponderosa pine forests in the Oregon Cascades. Most of the permanent plots were established during two intervals: from 1910 to 1948, and from 1970 to 1989. The earlier plots were established by U.S. Forest Service researchers to quantify timber growth in young stands of important commercial species and to help answer other applied forestry questions. The more recent period of plot establishment began under the Coniferous Forest Biome program of the International Biological Program during the 1970s, and continued under the Long-term Ecological Research program. A broader set of objectives motivated plot establishment since 1970, especially quantification of composition, structure, and population and ecosystem dynamics of natural forests. Plots have one of three spatial arrangements: (1) contiguous rectangles subjectively placed within an area of homogeneous forest; (2) circular plots subjectively placed within an area of homogeneous forest; and (3) circular plots systematically located on long transects to sample an entire watershed, ridge, or reserve. Rectangular study areas are mostly 1.0 ha or 0.4 ha (1.0 ac) in size (slope-corrected). Circular plots are 0.1 ha (0.247 ac), not corrected for slope. The tree stratum is the focus of work in closed-forest study areas. All trees larger than a minimum diameter (5 cm for most areas) are permanently tagged. Plots are censused every 5 or 6 years. Attributes measured or assessed at each census include tree diameter, tree vigor, and the condition of the crown and stem. The same attributes are recorded for trees (ingrowth) that have exceeded the minimum diameter since the previous census. In many plots tree locations are surveyed to provide a

Net Carbon Exchange of an Old-Growth Hemlock Forest at Harvard Forest HEM Tower since 2000

This project estimates carbon exchange rates of multiple forest types at Harvard Forest (see HF072) and compares them to long-term ongoing carbon exchange measurements at the EMS, which is located in a mesic, 60-90 year old red oak and red maple dominated forest on abandoned farmland (HF004). Measurements in each forest type are used to investigate climatic influences on carbon exchange. This mesic hemlock-dominated forest with most trees 100-200 years old on undisturbed soils stored only about 3 Mg/ha of carbon in 2001, compared to over 4 Mg/ha in the 60-90 year old oak/maple stand. However, both sites stored more carbon in 2001 than was measured in the oak/maple stand in any previous year since 1991 (see HF004). The hemlock forest behaved very differently from the oak-maple stand in that the highest rates of carbon storage occurred in spring, while there was very little carbon storage in mid to late summer. Statistical models of carbon exchange in the hemlock forest showed that carbon storage was positively related to daily minimum air temperature in spring, but negatively correlated with soil temperature in the summer. The first effect was attributable to a positive influence of above-freezing minimum temperatures on photosynthesis by hemlock foliage. The negative relationship of soil temperature to carbon storage by hemlock forest in summer was due to exponentially increasing soil and ecosystem respiration, accompanied by a neutral or negative effect of high air temperature on photosynthesis by hemlock trees (see HF063). These effects indicate that carbon storage in the hemlock forest could be strongly affected by climate warming, but the effects will probably be in opposite directions in spring and summer.

openCC0Dec 2024View details →

Tree Growth and Above-Ground Biomass at Harvard Forest HEM and LPH Towers since 2001

Tree diameter (“dbh”) at 1.25 m above ground were recorded and stainless steel dendrometer bands for trees above 10 cm dbh were attached. Increases in tree diameter were calculated from increases in the distance between holes punched in the dendrometer bands. Tree diameters and diameter increases were used to estimate aboveground biomass and aboveground carbon storage in order to characterize the forest at the flux tower sites, and to quantify the amount of carbon being stored aboveground annually.

Tree Growth in Hemlock and Deciduous Forests at Harvard Forest HEM and LPH Towers 2000-2005

Tree growth was measured to determine tree ages and growth rates and to quantify carbon storage in these forests, and to detect changes in growth and carbon storage that could be associated with climate changes or historic disturbances.

openCC0Nov 2023View details →

Dynamics of Old-Growth Forests on Wachusett Mountain in Princeton MA 1996-1997

One of the largest old-growth forests in southern New England was recently "discovered" on the exposed upper slopes of Wachusett Mountain, one of the most heavily used recreational areas in Massachusetts, less than 50 miles from urban Boston. Presettlement and early post-settlement data suggest that most of the area's forests were comprised of a mixture of Quercus rubra and northern hardwood species. Individual species abundances and recruitment dynamics in the four stands exhibit highly variable spatial and temporal patterns across sites that differ in aspect and exposure. Three uneven-aged hardwood stands contain Quercus rubra in the largest size classes, various amounts of Fagus grandifolia, Acer and Betula species in the middle size classes and dense thickets of Acer pennsylvanicum, Acer spicatum, and Hamamelis virginiana in the small size classes. Several individuals of Q. rubra, B. lenta, and B. alleghaniensis are at or very near the maximum longevity known for these species. Of particular significance is the presence of Q. rubra exceeding 250 - 300 years of age. A Tsuga canadensis stand contains unimodal size and age distributions, with trees less than 60-cm dbh and 100 to 300 years old. Widespread Quercus rubra recruitment occurred on all sites from the 1600s through the early 1800s, when it dropped precipitously except for scattered individuals on more open talus sites, and was replaced by either Tsuga or Acer and Betula species. The historical change in recruitment from Quercus to more shade-tolerant species evidently was driven by a change in disturbance regime from an early period when fire was a major factor controlling forest dynamics to a period over the last two centuries when hurricanes (1815 and 1938), frequent wind, ice, and snow damage, but no fire, are documented. The asynchronous nature of tree-ring releases and suppression and the relatively low amount of coarse woody debris corroborate this interpretation. Chronic canopy damage through time p

Tree Growth in Macrosystems Biodiversity Project at Harvard Forest 2011-2013

Patterns of biodiversity, such as the increase toward the tropics and the peaked curve during ecological succession, are fundamental phenomena for ecology. Such patterns have multiple, interacting causes, but temperature emerges as a dominant factor across organisms from microbes to trees and mammals, and across terrestrial, marine, and freshwater environments. However, there is little consensus on the underlying mechanisms, even as global temperatures increase and the need to predict their effects becomes more pressing. The purpose of this project is to generate and test theory for how temperature impacts biodiversity through its effect on biochemical processes and metabolic rate. A combination of standardized surveys in the field and controlled experiments in the field and laboratory measure diversity of three taxa -- trees, invertebrates, and microbes -- and key biogeochemical processes of decomposition in seven forests distributed along a geographic gradient of increasing temperature from cold temperate to warm tropical. This dataset contains annual growth measurements of trees along a series of transects using the measures of diameter at breast height and/or diameter and ground height at the five Gentry plots set up at Harvard Forest. These plots were set up by the Enquist Lab (PI, Brian Enquist) from the University of Arizona as part of a macrosystems biodiversity and latitude project supported by the National Science Foundation under Cooperative Agreement DEB#1065836.

Phenology and Vegetation Growth in Prospect Hill Soil Warming Experiment at Harvard Forest 1992-1993

As the mean annual temperature of northeast North America rises as a component of global climatic change, it is important to understand how the predominant vegetation of the region will be affected. Existing experimental and correlative evidence from field sites suggests that temperature rise will significantly modify soil processes, nutrient availability, and plant growth. We investigated the responses of temperate deciduous forest vegetation to artificial soil warming at 20 sampling dates during the 1992 and 1993 growing season. We explored whether soil warming measurably altered growth and the temporal dynamics of leaf and fruit production in 26 species of three contrasting plant growth forms (herbaceous perennials, shrubs, and canopy trees). We hypothesized that soil warming would exert differential effects on emergence, phenology, leaf expansion rates, growth, photosynthesis, and vegetative and sexual reproduction among species, with implications for changing community structure in these forests. Timing of leaf emergence and flower production was not affected by treatment in saplings; however, mature trees and shrubs leafed out slightly earlier and in larger numbers in heated plots. Soil warming significantly enhanced relative growth in stem diameters of woody plants, especially shrubs, in 1992. This effect was less pronounced in 1993. Species richness was lower in heated plots than in intact control plots in both years; disturbed but unheated control plots showed the lowest species richness of all plots. Changes in relative abundance of herbaceous species from 1992 to 1993 were not significantly affected by treatment. Rank abundances of species were more stable between years in the heated and disturbance-control plots than in the intact plots. Total density of herbaceous species was highest in heated plots during April and May of both years, reflecting greatly accelerated emergence of two dominant species, Maianthemum canadense and Uvularia sessilifolia, due t

Gene Expression and Tree Growth in the CTFS-ForestGEO Plot at Harvard Forest 2017-2019

Major goals in ecosystem ecology have been to scale from leaves to canopies and to determine whether individual-level, intra-species and inter-specific variation is critical for models projecting ecosystem processes now and in the future. The project is important in that it examines these issues in detail considering genotypes and levels of gene expression all the way up to canopy level CO2 flux. Ecological genomics and transcriptomics are nascent fields that have been primarily restricted to model species in natural and (mostly) controlled environments. To date, we have very few studies of non-model organisms in nature and/or studies of functional genomics through space and time. The research is producing extraordinarily rich datasets regarding the gene expression of trees across populations, through space in each population, across the growing season and across years and linking this information to growth and gas exchange. It will, therefore, provide tremendous insights into how much variation exists in nature thereby guiding sampling designs in future ecological 'omics projects. More importantly, it will provide unusually detailed phenotypic information for important non-model species that have large impacts on the CO2 flux of eastern US forests.

Effect of Warming on Thermal Adaptation of Soil Microbial Growth Traits at Harvard Forest 2013-2023

Adaptation of soil microbes due to warming from climate change has been observed, but it remains unknown what microbial growth traits are adaptive to warming. We studied bacterial isolates from the Harvard Forest Long-Term Ecological Research site, where field soils have been experimentally heated to 5ºC above ambient temperature with unheated controls for thirty years. We hypothesized that Alphaproteobacteria from warmed plots have (1) less temperature sensitive growth rates; (2) higher optimum growth temperatures; and (3) higher maximum growth temperatures compared to isolates from control plots. We made high-throughput measurements of bacterial growth in liquid cultures over time and across temperatures from 22-37ºC in 2-3ºC increments. We estimated growth rates by fitting Gompertz models to the growth data. Temperature sensitivity of growth rate, optimum growth temperature, and maximum growth temperature were estimated by the Ratkowsky 1983 model and a modified Macromolecular Rate Theory (MMRT) model. To determine evidence of adaptation, we ran phylogenetic generalized least squares tests on isolates from warmed and control soils. Our results showed evidence of adaptation of higher optimum growth temperature of bacterial isolates from heated soils. However, we observed no evidence of adaptation of temperature sensitivity of growth and maximum growth temperature. Our project begins to capture the shape of the temperature response curves, but illustrates that the relationship between growth and temperature is complex and cannot be limited to a single point in the biokinetic range.

openCC (other)Dec 2024View details →

Tree-ring measurements from permanent plot in old-growth hemlock-hardwood forest, Huron Mts., MI

This package includes tree growth-ring widths for increment cores collected from a long-term 'macroplot' established in old-growth hemlock-northern hardwoods forest at the Huron Mts. of northern MI. Tree demographic monitoring data for the entire ca. 3.0 ha macroplot are available in the EDI package edi.1416.1. In 1994 and 1995, increment cores were taken for all 'core-able' trees greater than ~ 10 cm diameter for a subsection of the macroplot about 1 ha in area, along with some additional Tsuga canadensis trees beyond that 1 ha section. Cores are NOT cross-dated. See Methods for more details. This data-package may be cross-referenced to the demographic data in edi.1416.1 using stem numbers.

openCC (other)Jan 2025View details →

Effects of inoculation of restored and remnant prairie soils on growth, nodulation, and root colonization of three prairie legumes

In this dataset, we present legume biomass, nodule number, and % root colonization of three species of prairie legumes (Amorpha canescens, Lespedeza capitata, and Dalea purpurea) when inoculated with soil from one of 6 remnant or 10 restored prairies in southwest Michigan, USA. Plants were grown for 10 weeks in a growth chamber.

openCC (other)Apr 2025View details →

Tree-ring measurements from permanent study plot in old-growth hemlock-hardwood forest, Dukes RNA, Hiawatha NF, Marquette Co., MI

This package includes tree growth-ring widths for increment cores collected from a long-term 'macroplot' established in old-growth hemlock-northern hardwoods forest at the Dukes Research Natural Area/Dukes Experimental Forest in the Hiawatha National Forest in Marquette Co., MI. Tree demographic monitoring data for the entire ca. 3.0 ha macroplot, from 1992 to 2019, are available in the EDI package edi.1526.1. In 1993, 1994 and 1995, increment cores were taken for all 'core-able' trees greater than ~ 10 cm diameter for a subsection of the macroplot about 1 ha in area. Trees that were obviously badly rotten and hollow or steeply leaning were not cored. Cores are not cross-dated. See Methods for more details. This data-package may be cross-referenced to the demographic data in edi.1526.1 using stem numbers.

openCC (other)May 2025View details →

Seedling composition, growth, and dynamics in tropical rain forest, La Selva, Costa Rica (1983-1996)

Recruitment, growth, and survivorship of the regeneration stages of trees and lianas were studied in old-growth tropical rain forest at La Selva Biological Station of the Organization for Tropical Studies (OTS), near Puerto Viejo de Sarapiquí, Heredia Province, in the Caribbean lowlands of Costa Rica. A total of 48 permanent seedling transects each measuring 10 m x 0.5 m were established at random locations within three La Selva permanent forest inventory plots. The forest plots occupy contrasting landforms: Plot 1 (4.4 ha), old alluvial terrace; Plot 2 (4.0 ha), swamp forest and low hills; and Plot 3 (4.0 ha), steeply dissected terrain with residual volcanic soils. Seedling locations are georeferenced within the grid system of the permanent forest inventory plots, facilitating spatial analysis of seedling populations with respect to adult cohorts. Beginning in June 1983, all seedlings ≤ 0.5 m in height belonging to tree and liana species capable of reaching 10 cm diameter at breast height (dbh) at maturity were tagged, identified to species or morphospecies, mapped to the nearest cm, and measured in height to the nearest cm. Over a period of 18 months, a total of 6403 seedlings belonging to 167 species were tagged. Monitoring and re-measurement of all tagged individuals continued through November 1996. Data include 17 census dates over a period of 13.5 years. At the time of the final census, only 97 individuals (1.52% of the tagged seedlings) were still alive, representing 43 species (25.7% of the initial number). The largest surviving seedling had grown in height from 4 cm to 13 meters during the study period. This dataset on the regeneration stages in old-growth tropical rain forest in the La Selva permanent inventory plots forms a complement to the studies of long-term growth and demography of these species and assemblages at adult stages within the plots. Forest inventory data for trees and lianas ≥ 10 cm dbh in the permanent plots in which the seedling transec

openCC0Jan 2026View details →

2021-2024 Juvenile Chinook Salmon Rearing and Growth on the Lower American River, California

The primary goal of the Central Valley Project Improvement Act is to at least double natural production of Chinook Salmon ( Oncorhynchus tshawytscha ) in California Central Valley (CCV) streams on a sustainable basis. Beginning in 2008, semi-annual gravel augmentation and off channel habitat enhancement projects were implemented on the Lower American River (LAR) by Reclamation and USFWS, in partnership with the Sacramento Water Forum, as part of the LAR habitat enhancement program. The overall vision for the habitat enhancement program is to restore ecosystem processes by rehabilitating and enhancing critical channel, floodplain, and riparian habitats for juvenile and adult anadromous salmonids, thus promoting the recovery of healthy and diverse Chinook Salmon and steelhead ( O. mykiss ) populations. Off channel rearing habitat has been identified as a limiting factor in meeting CCV salmon population goals. While numerous studies have documented positive relationships between off channel habitat and juvenile rearing on the LAR, it is not known how long juveniles remain in off channel habitat compared with the main channel, whether rearing in off channel habitat enhances growth compared with the main channel, whether the relative value of off channel habitat for juvenile production depends on how long it has been inundated, or whether juvenile diet in off channel habitat differs from that in the main channel. To better understand these relationships, we conducted a mark-recapture study under a range of hydrological conditions between 2021-2024 using passive integrated transponder (PIT) tagged wild juvenile Chinook Salmon coupled with seining surveys at five off channel restoration sites on the LAR designed for rearing, as well as nearby main channel control sites that were also suitable rearing habitat. First, we investigated whether side channel habitats in restored reaches support higher Chinook Salmon densities than main channel control habitats. Density was estim

openCC (other)Oct 2025View details →

Towers Forestry Plot, Long-term Vegetation Monitoring in a 1-ha old-growth Rainforest, La Selva Research Station, OTS, Sarapiquí, Heredia, Costa Rica, 2010–2020

The Towers Plot is a 1-hectare permanent vegetation plot established in 2010 under the canopy towers at La Selva Research Station, Sarapiquí, Heredia, Costa Rica. The plot was created by the Organization for Tropical Studies (OTS) to monitor long-term changes in forest structure, composition, and dynamics in an old-growth tropical rainforest. All woody stems with a diameter at breast height (DBH) of 10 cm or greater—including trees, palms, and lianas—were tagged, mapped, and measured following standardized procedures. Censuses were conducted between 2010 and 2020 to document growth, mortality, and recruitment. The dataset includes taxonomic identifications, stem diameter measurements, spatial coordinates within the plot, and metadata describing field methods and species composition. The plot was established beneath three canopy towers that had been previously constructed through the NSF-funded Major Research Instrumentation (MRI) project, NSF 0722741, which provided key infrastructure for canopy and environmental research at La Selva. This proximity created a valuable opportunity to integrate vegetation monitoring with existing environmental instrumentation. Johana Hurtado, coordinator of the Tropical Ecology, Assessment and Monitoring (TEAM) project at La Selva, collaborated with OTS staff in the establishment of the plot, ensuring methodological consistency with other tropical forest monitoring sites. This dataset provides a comprehensive record of woody plant diversity and forest structure in a lowland old-growth Neotropical rainforest. It supports research on forest dynamics, carbon storage, and ecosystem change. The overall monitoring project is ongoing; this data package contains observations from 2010 through 2020.

Tree Growth and Coarse Woody Debris in Regenerating Forests at Harvard Forest since 2008

This project is a field-based study to measure sequestration of atmospheric carbon dioxide in a regenerating New England forest. This study established long-term biometric plots suitable for measuring changes in carbon storage through time in three forest stands: an early-20th-century conifer plantation, a naturally regenerating former conifer plantation harvested in the 1990s, and a conifer plantation scheduled for harvest next winter. The first three years of this project determined the initial carbon budget of these forest stands, measured carbon fluxes into and out of these stands, and laid the groundwork for future investigations. Subsequent years will investigate larger-scale questions, such as how successional patterns affect carbon sequestration, and how these patterns change with stand age. The work also addresses how forestry practices influence carbon sequestration, and provide guidance for how forest management could enhance terrestrial carbon uptake in the future.

openCC0Jan 2024View details →

Growth Rates of Xanthoparmelia Lichens in North Cemetery, Petersham MA 2005-2011

Lichens fix carbon dioxide from the air to build biomass. Crustose and foliose lichens grow as nearly flat, circular disks. While smaller lichens grow slowly, but with small, steady increases in radial growth rates, larger lichens grow more quickly, with radial velocities that remain roughly constant over the lifetime of an individual. These basic features follow directly from a novel mathematical model based on the diffusion of carbon dioxide around a lichen, and its absorption by the thallus. Smaller lichens fix carbon dioxide across the entire thallus, but larger lichens fix carbon dioxide disproportionately at edges. Because local edges remain the primary source of carbon as a lichen grows ever larger, radial growth rates remain constant. Predicted growth dynamics depend on four measurable parameters, and tests of the model against data suggest the model provides an accurate, robust, and universal framework for understanding the growth dynamics of lichens in nature.

Quantifying Growth and Structure along Forest Edges in the Northeastern USA 2010-2021

Fragmentation transforms the environment along forest edges. The prevailing narrative, driven by tropical research, suggests that edge environments increase tree mortality and structural degradation resulting in net decreases in ecosystem productivity. We show that temperate forest edges exhibit increased forest growth (basal area increment; BAI) and biomass (basal area; BA) with no change in total mortality relative to the forest interior. To assess forest edges, we analyzed more than 48,000 forest inventory plots (USDA FIA) across the north-eastern US using a quasi-experimental matching design. At forest edges adjacent to anthropogenic land covers, we report increases of 36.3% and 24.1% in forest growth and biomass, respectively. We then scale the edge impacts on growth (along anthropogenic edges only) across our study area using maps of land-cover and forest type. We find large variability in the effect of including edges on estimates of total forest growth, largely driven by differences in the prevalence of fragmentation. Estimated increases in forest growth range from a 23% increase in the agricultural-dominated western areas, a 2% increase in the least-fragmented northern regions, and a 15% increase within the metropolitan east coast. Finally, we also quantify forest fragmentation globally, at 30-m resolution, showing that temperate forests contain 52% more edge forest area than tropical forests. We provide two tables containing the post-matched dataset of FIA subplots, including subplot BA, BAI, and edge status. We include the associated environmental covariates, extracted from gridded raster data, and used in our matching and statistical analyses. Due to plot confidentiality restrictions we do not provide spatial locations of the FIA subplots, but we do provide unique plot identifiers that allow users to link each record to the publically-available data provided by the USDA FIA database (https://apps.fs.usda.gov/fia/datamart/). This dataset can be used to re

openCC (other)Sep 2023View details →

MCR LTER: Coral Reef: 3D photogrammetry improves measurement of growth and biodiversity patterns in branching corals; data for Curtis 2023, Coral Reefs

These data and code were generated in support of the manuscript: Curtis JS, Galvan JW, Primo A, Osenberg CW, and AC Stier, Coral Reefs. We collected manual and photogrammetry-based measurements of coral size and volume to examine which method best described short-term coral growth and links between coral habitat and biodiversity of CAFI (coral-associated fishes and invertebrates). This study was completed between August and December 2019 on an experimental array located in the back reef off the south shore of Moorea, French Polynesia. These data were published in Coral Reefs, analyses and full methods descriptions of this model can be found in the manuscript “3D photogrammetry improves measurement of growth and biodiversity patterns in branching corals”. This manuscript uses data collected by the U.S. National Science Foundation's (NSF) Moorea Coral Reef Long Term Ecological Research (MCR LTER) site under Grant No. OCE 2224354 (and earlier awards). Additional financial support to the MCR LTER site was provided through a generous gift from the Gordon and Betty Moore Foundation. Research was completed under permits issued by the French Polynesian Government (Délégation à la Recherche) and the Haut-commissariat de la République en Polynésie Francaise (DTRT) (Protocole d'Accueil 2005-2023).