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openCC (other)Aug 2023View details →

Bald cypress radiocarbon and dendrochronological data from trees located in the Altamaha Wildlife Management Area and on Sapelo Island, Georgia, USA

Ancient bald cypress trees buried under anoxic mud on the Altamaha Wildlife Management Area islands were sampled, prepared, radiocarbon dated, and the ringwidths measured for crossdating. Modern bald cypress samples were also obtained from Sapelo Island. Tree rings were measured using a Velmex and Measure J2X software and/or the ObjectJ extension of ImageJ. Measured radii were crossdated using visual dendrochronological methods and Cofecha software. Tree rings anchored to the present date back to 3161 B.C.E. and extend to 2016 C.E. In addition, the oldest two trees provide another 529 years of ringwidth data. This work was conducted under the National Science Foundation Doctoral Dissertation Improvement Award: Human Adaptation to Long Term Environmental Change (Award #1834682). All samples are part of the accessioned collections of the University of Georgia Laboratory's of Archaeology.

Tree Ring Data from the Lyford Mapped Tree Plot at Harvard Forest 1861-2014

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted annually. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from three 20m radius plots set within the Lyford Plot at the Harvard Forest. The Lyford Plot has been remeasured, on average, decadally since 1969. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time. Dye et al. (2016) have shown that these data fall within the range of uncertainty of census data sampled in similar plots going back to 1969. Dye, A., Barker Plotkin, A., Bishop, D., Pederson, N., Poulter, B. and Hessl, A., 2016. Comparing tree‐ring and permanent plot estimates of aboveground net primary production in three eastern US forests. Ecosphere, 7(9).

Tree Ring Data from the Harvard Forest EMS Tower 1896-2014

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted annually. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from two 20m radius plots set within the footprint of the EMS tower plot at the Harvard Forest installed and continuously operated since 1989. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time. Dye et al. (2016) have shown that these data fall within the range of uncertainty of census data sampled in the Harvard Forest Lyford plot going back to 1969. Dye, A., Barker Plotkin, A., Bishop, D., Pederson, N., Poulter, B., Hessl, A. 2016. Comparing tree-ring and permanent plot estimates of aboveground net primary production in three eastern U.S. forests. Ecosphere 7: e01454.

Tree Ring Data from Goose Egg State Forest NY 1681-2014

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted at annual time steps. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from three 30m radius plots set in Goose Egg State Forest in New York State. We chose this location because it has old oak dominated forests that can be compared to the long-term forests being studied for carbon dynamics at the Harvard Forest. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time to understand forest recovery and carbon dynamics in a heavily disturbance forest. Recruitment dates for some of the trees from these plots have been published in Pederson et al. (2017). Pederson, N., Young, A. B., Stan, A. B., Ariya, U., Martin-Benito, D. 2017. Low-Hanging DendroDynamic Fruits Regarding Disturbance in Temperate, Mesic Forests. In: Amoroso, M. M., Daniels, L. D., Baker, P. J., Camarero, J. J., Dendroecology: Tree-Ring Analyses Applied to Ecological Studies, Springer, Cham., Switzerland.

Tree Ring Data from North Round Pond in Pisgah State Forest NH 1754-2015

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted at annual time steps. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from four 30m radius plots set in the vicinity of North Round Pond in Pisgah State Forest, New Hampshire. Two plots are set in broadleaf-dominated forests while two are set in oak-mixed conifer dominated forests. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time. While a strong hurricane in September 1938 knocked down 80% of a stand ca 3.5 km SSE of these stands and the stands in the vicinity of the North Round Pond are set on N- and NW-facing slopes, and thus potentially shielded by the strong tropical winds, they, too, were disturbed by the hurricane of 1938. However, there are some very old trees and patches of trees in this landscape, while, at the same time, we suspect some logging impacted parts of some of these plots in the 1960s, like in North Round Pond Plot 1. The forest stands have since regrown and the plots we installed can be used to understand forest recovery and carbon dynamics in a heavily disturbance for

Tree Ring Data from the Harvard Tract in Pisgah State Forest NH 1675-2015

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted at annual time steps. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from two 30m radius plots set within Harvard’s Pisgah Tract in Pisgah State Forest, New Hampshire. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time. Famously, 80% of this tract was knocked down in September 1938 by a strong hurricane. The forest has sine regrown and the plots we installed can be used to understand forest recovery and carbon dynamics in a heavily disturbance forest. Given that this was a known/decently documented event, these data were used by Trotsiuk et al. (2018) to test various growth release methods as applied to tree-ring data. Trotsiuk, V., Pederson, N., Druckenbrod, D. L., Orwig, D. A., Bishop, D. A., Barker Plotkin, A., Fraver, S., Martin-Benito, D. 2018. Testing the efficacy of tree-ring methods for detecting past disturbances. Forest Ecology and Management 425: 59-67.

Tree Ring Data from Rooster Hill in Adirondack State Park NY 1828-2015

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted at annual time steps. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from two 30m radius plots set Rooster Hill in New York State. We chose this location because it has oak dominated mixed forests that can be compared to the long-term forests being studied for carbon dynamics at the Harvard Forest. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time to understand forest recovery and carbon dynamics in a heavily disturbance forest.

openCC (other)Jun 2025View details →

Tree seedling abundance mediated by local neighborhood effects and microsite conditions

Tree recruitment across elevational gradients is shaped by myriad factors, including abundance of nearby conspecific adults and abiotic establishment conditions. We measured seedling abundance and overstory basal area for six tree species that dominate northern temperate and montane boreal forests on mountains in the northeastern United States. Data were collected on elevational transects spaced at 100m-intervals of elevation on ten mountains. Associated environmental variables, including vegetation cover, substrate, microclimate, and light environment, were also collected.

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

openCC (other)Apr 2023View details →

Meteorological data from the Discovery Tree at the Andrews Experimental Forest, 2015 to present

The upper-canopy of forests is known to experience a very different leaf wetness than the rest of the forest: it is often simultaneously brighter, hotter, windier, and drier. The upper canopy also contains most of the leaf area, and because it absorbs most of the solar radiation, it accounts for the great majority of carbon and water exchanges in most forests. Critically, this is also the zone where most climate variations and stress likely manifest. The upper canopy is also the region of the forest that is sampled by satellite imagery. Intensive canopy microclimate monitoring provides connections to satellite-based imagery at varying temporal and spatial scales in order to scale across the Andrews landscape and improves our understanding of forest function and its response to climate change. A 50 meter old growth tree, called the Discovery Tree, was instrumented with various sensors. A thermal infrared camera was installed in March 2014, which collects surface temperatures of the old-growth forest and the adjacent secondary-growth forest. Since then, the scope of information being acquired in real-time has increased to include temperature, leaf wetness, relative humidity, soil temperature, soil moisture, wind direction and speed. This suite of data serves as a glimpse into the canopy and soil processes we are unaware of when our feet are planted firmly on the ground. These measurements complement and leverage ongoing, long-term climate measurements collected in the sub-canopy and at the climate stations located across the Andrews forest, and potentially link with Lidar data on canopy structure and planned soil moisture measurements. Canopy thermal imaging and microclimate measurements have been established for ecophysiological applications such as monitoring the response of forest tree canopies to climate variations, including heat and drought stress.

openOpenApr 2025View details →

Cooperative Alaska Forest Inventory (CAFI): I - Tree Inventory Data 1994-2024

The CAFI is a repeated forest measurement project established in forest stands throughout interior and southcentral Alaska. The CAFI was launched in 1994 and measurements were done at a 5-year interval until 2015. The project was on hiatus between 2016 and 2019 but picked back up again in 2020 and will continue at a 10-year interval. Total of 205 permanent plots have been established and each plot has been measured up to 6 times. The CAFI is the most extensive forest monitoring program, both in spatial and temporal scale, in interior and southcentral Alaska today. This is the tree data of the CAFI. The CAFI is a repeated forest measurement project established in forest stands throughout interior and southcentral Alaska. The CAFI was launched in 1994 and measurements were done at a 5-year interval until 2015. The project was on hiatus between 2016 and 2019 but picked back up again in 2020 and will continue at a 10-year interval. Total of 205 permanent plots have been established and each plot has been measured up to 6 times. The CAFI is the most extensive forest monitoring program, both in spatial and temporal scale, in interior and southcentral Alaska today.

Tree Canopy Leaf Area Index in CRUI Land Use Project at Harvard Forest 1997

Numerous variables related to land use disturbance and recovery processes can influence forest composition and structure. We’ve measured differences in forest communities in six sites that were formerly plowed, pastured, or continuously forested woodlots in Prospect Hill. None of the sites had noticeable canopy gap disturbance at the time of the measurements. Leaf area index (LAI) was measured with an LAI-2000 plant canopy analyzer (Li-Cor, Inc., Lincoln, NE) at all 77 edge and interior intersection points in the 30 m x 50 m permanent plot (7 columns x 11 rows) in 5 of our 6 land use sites. Under-canopy measurements were made in each site over 25-30 minutes during midday hours (11:00-2:30 EST) on overcast days near solstice (June 13, 18). The under-canopy readings were contrasted with an open-sky measurement taken in an open field near the Harvard Forest headquarters just before beginning data collection in each site. LAI averaged 3.98 and ranged from 2.28 to 5.93 across all sites. W1 had the highest site-level mean (4.62) and maximum (5.93) LAI while S2 had the lowest values (mean = 3.41, max = 4.55). The woodlot also showed the greatest spatial variation as measured by C.V., while plow #1 showed the least variation.

Mapped Trees in CRUI Land Use Project at Harvard Forest 1996-2006

Numerous variables related to land use disturbance and recovery processes influence forest composition, structure, and growth. We measured forest communities in six sites that were formerly plowed, pastured, or continuously forested woodlots in Prospect Hill to test predictions about species composition, stand structure, and productivity in response to agricultural land use legacies. A permanent 30 x 50 m plot gridded in 5 x 5 m sub-plots was established in each of the 6 sites. All trees at least 2.5 cm DBH (diameter at breast height, 1.3 m) were mapped visually in the field, marked with an aluminum tag, and their DBH recorded in summer 1996. Individual boles of multi-stemmed trees were measured separately and a composite single DBH was calculated. Standing dead trees were also mapped and their DBH recorded as well. The 1996 data were used to determine above ground woody biomass using allometric equations for individual trees. The permanent plots were re-surveyed ten years later in fall 2006. The status of each tree mapped in 1996 was recorded (alive, dead standing, dead fallen, forked) and DBH’s were re-measured. Additional trees that grew across the 2.5 cm DBH threshold during the ten-year period were mapped and their DBH’s measured. Composite diameters and above ground woody biomass were determined for forked trees as in 1996. The 2006 re-measurements were used to analyze changes in species composition, stand structure (density, diameter distribution), and mortality patterns among species and size classes, and to calculate net changes in above ground woody biomass across the ten-year period.

Tree Seedlings in CRUI Land Use Project at Harvard Forest 1996

Forests recovering from agricultural legacies differ in many ways that influence tree seed dispersal and seedling establishment patterns. We recorded the number of seedlings (less than 0.5 m tall) of all tree species on a 1 x 1 m resolution across six land use legacy sites (2 plowed, 2 pastured, 2 permanent woodlot) in summer 1996 to test several predictions about seedling abundance, diversity, and dispersion patterns, and their relationships to forest structure, microclimates, and soil resources.

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.

Bayesian Analysis of Tree Distributions Across Space and Time in Eastern North America 2010-2011

The distributions of many organisms are spatially autocorrelated, but it is unclear whether including spatial terms in species distribution models (SDMs) improves projections of future species distributions. We provide the first comparative test of a purely spatial SDM, a purely non-spatial SDM, and an SDM that combines spatial and environmental information. Spatial SDMs provided better fits to the calibration data, more accurate predictions of a hold-out validation data set of modern trees, and lower false positive rates at all time periods than non-spatial SDMs. Hindcasted projection of spatial SDMs had higher variance than those of non-spatial SDMs. Overall predictive performance of non-spatial and spatial SDMs varied temporally and as a function of niche overlap. Ecological modelers should include spatial terms in SDMs used for projecting future distributions of species.

Effects of Warming on Tree Species Recruitment at Harvard Forest and Duke Forest since 2009

Climate change is restructuring forests of the United States, although the details of this restructuring are currently uncertain. Rising temperatures of 2 to 8 deg C and associated changes in soil moisture will shift the competitive balance between species that compete for light and water, changing their abilities to produce seed, germinate, grow, and survive. We are using large scale experiments to determine the effects of warming on the most sensitive stage of species distributions, i.e., recruitment, in mixed deciduous forests in southern New England and in the Piedmont region of North Carolina. Two questions organize our proposed research: (1) Might temperate tree species near the "warm" end of their range in the eastern United States decline in abundance during the coming century due to projected warming? and (2) Might trees near the "cool" end of their range in the eastern United States increase in abundance, or extend their range, during the coming 100 years because of projected warming? To explore these questions, we are exposing seedlings to air and soil warming experiments in two eastern deciduous forest sites; one at the Harvard Forest (HF) in central Massachusetts, and the other at the Duke Forest (DF) in the Piedmont region of North Carolina. We focus on tree species common to both Harvard and Duke Forests (such as red, black, and white oaks), those near northern range limits (black oak, tulip poplar), and those near southern range limits (yellow birch, sugar maple). At each site, we plant seeds in common gardens established in temperature-controlled, open-top chambers. The experimental design is replicated and fully factorial and involves three temperature regimes (ambient, +3 deg C and +5 deg C) and two light regimes (closed forest canopy (low light) and gap conditions (high light)). Measured variables include Fall/Spring responses to temperature and mid-Summer responses to low soil moisture. This research will advance our understanding of how the abu

Sap Flow of Northern Red Oak Trees Under Ecosystem Warming at Harvard Forest 2011

Over the next century, air temperature increases up to 5 °C are projected for the northeastern USA. Because evapotranspiration dominates water loss from terrestrial ecosystems, tree ecophysiological response to warming will have important consequences for forest water budgets. We measured growing season sap flow rates in mature northern red oak (Quercus rubra L.) trees in a combined air (up to 5.5 °C above ambient) and soil (up to 1.85 °C above ambient at 6-cm depth) warming experiment at Harvard Forest, MA, USA. Principal components analysis found air and soil temperatures had the largest effects on sap flow. On average, each 1 °C increase in temperature increased sap flow rates by approximately 1100 kg H2O m-2 sapwood area day-1 throughout the growing season and by 1200 kg H2O m-2 sapwood area day-1 during the early growing season. Reductions in the number of cold winter days correlated positively with increased sap flow at night during the early growing season (a decrease of 100 heating-degree-days was associated with a sapflow increase of approximately 5 kg H2O m-2 sapwood area day-1). Soil moisture declined with increased treatment temperatures, and each soil moisture percentage increase resulted in an increase in sap flow of approximately 360 kg H2O m-2 sapwood area day-1. At night, soil moisture correlated positively with sap flow rate. These results demonstrate that warmer air and soil temperatures in winter and throughout the growing season lead to increased sap flow rates, which could affect forest water budgets throughout the year.

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.