Harvard Forest

Data Archive

HF453

Annual Tree Health and Mortality Survey of the Harvard Forest CTFS-ForestGEO Plot 2021-2024

Related Publications

Data

• hf453-01: tree mortality census data 2021-2024 (preview)

Overview

• Lead: Daniel Johnson
• Investigators: Lukas Magee, David Orwig
• Contact: Information Manager
• Start date: 2021
• End date: 2024
• Status: complete
• Location: Prospect Hill Tract (Harvard Forest)
• Latitude: +42.54 degrees
• Longitude: -72.18 degrees
• Elevation: 340 to 368 meter
• Datum: WGS84
• Taxa:
• Release date: 2026
• Language: English
• EML file: knb-lter-hfr.453.1
• DOI: digital object identifier
• EDI: data package
• DataONE: data package
• Related links:
• Harvard Forest CTFS-ForestGEO Mapped Forest Plot since 2014
• Study type: short-term measurement
• Research topic: conservation and management; invasive plants, pests and pathogens
• LTER core area: primary production, population studies, disturbance patterns
• Keywords: community composition, forest dynamics, invasive species, mortality, remote sensing, tree maps
• Abstract:

  The rate of tree mortality has been increasing, but why and where? Understanding the scope and scale of tree mortality is important because tree death can have a large impact on carbon dynamics and reduce biodiversity quickly. Mortality events most often occur at the scale of the individual or a small group of trees in a forest. Our ability to detect shifts in tree mortality and determine the causal factors responsible is defined by the intensity, scale, and frequency of our observations. Currently, most observations are too coarse in spatial scale and too infrequent in time to determine causal factors of mortality or how they vary across space and time and lack detail of why a tree died.

  Determining the uncertainty in tree mortality associated with the scale of observation is critical for making well informed estimates of carbon dynamics and predictions of forest community trajectories. The macroecological challenge lies gathering enough data on the ground to allow scaling up to broad regions with remote sensing products that can detect mortality events and changes in biomass at landscape and continental scales while minimizing uncertainty in our estimates. Our objective is to address this challenge and build scalable models of tree mortality with underlying factors associated with tree death.

  Each July for four years, we collected annual health and mortality data on all trees ≥10 cm diameter at breast height across the 35 ha ForestGEO megaplot at Harvard Forest. We assessed tree health by assigning any of 20 factors associated with death to all trees. We also collected crown metrics including the position in the canopy strata, percentage of crown structure intact, and percentage of crown living.

• Methods:

  We performed a field census to assess tree health within the 35-ha ForestGEO plot. This census involves conducting comprehensive visual examinations of all stems greater than 10 cm in diameter, focusing on indicators such as canopy condition, pests and pathogens, and physical damages. These field observations were meticulously recorded to create a detailed dataset capturing the health status of individual trees across the study area.

• Organization: Harvard Forest. 324 North Main Street, Petersham, MA 01366, USA. Phone (978) 724-3302. Fax (978) 724-3595.

• Project: The Harvard Forest Long-Term Ecological Research (LTER) program examines ecological dynamics in the New England region resulting from natural disturbances, environmental change, and human impacts. (ROR).

• Funding: National Science Foundation LTER grants: DEB-8811764, DEB-9411975, DEB-0080592, DEB-0620443, DEB-1237491, DEB-1832210. Other funding: National Science Foundation Macrosystems grant: DEB-2106015

• Use: This dataset is released to the public under Creative Commons CC0 1.0 (No Rights Reserved). Please keep the dataset creators informed of any plans to use the dataset. Consultation with the original investigators is strongly encouraged. Publications and data products that make use of the dataset should include proper acknowledgement.

• License: Creative Commons Zero v1.0 Universal (CC0-1.0)

• Citation: Johnson D. 2026. Annual Tree Health and Mortality Survey of the Harvard Forest CTFS-ForestGEO Plot 2021-2024. Harvard Forest Data Archive: HF453 (v.1).

Detailed Metadata

hf453-01: tree mortality census data 2021-2024

1. StemTag: unique tag for each tree that can be matched to the tree census data found in the related datasets
2. year: year data was collected (Always in July of that year)
3. status: health status of the tree
   • A: alive with no visible health issues
   • AU: alive but has at least one health issue
   • DC: dead and down on the ground
   • DN: dead and not found
   • DS: dead and standing
4. CP: crown position in the canopy strata
   • 1: understory with no direct light
   • 2: understory with side light only
   • 3: codominant with 15-90% direct light
   • 4: dominant with 90+% direct light
   • 5: emergent with crown well above the surrounding trees
5. PercCI: percentage of the crown woody material intact (unit: dimensionless / missing value: NA)
6. PercCL: percentage of the crown that is has living foliage (unit: dimensionless / missing value: NA)
7. Lean: angle (degrees) from vertical based on the angle from the base of the trunk to 1.3 m above the ground (unit: dimensionless / missing value: NA)
8. FAD: factor associated with death is a list of tree health codes that signify how a tree is unhealthy. AN: Animal damage; B: Broken bole; BB: Bark beetles; CR: Crushed; DF: Defoliation; F: Fungi; HS: Hollow stem; I: Insect infection; K: Canker; L: Lightning; LF: Leaf damage; OT: Overtopped; R: Rot; R1: Root damage; R2: Armallaria Root rot; S: Slope failure; U: unknown; UP: Up-rooted; W: Wound; Fi: Fire
9. wound: severity scale for any wound present
   • 1: small damage, smaller in area than a square of DBH x DBH in shape
   • 2: large damage, greater in area than a square of DBH x DBH in shape
   • 3: massive damage, affecting more than 50% of the basal area (i.e., a very deep and extensive wound) or more than 50% of the living length
10. canker: severity scale for any canker present
    • 1: small deformity area, smaller in area than a square of DBH x DBH in shape
    • 2: big deformity, greater in area than a square of DBH x DBH in shape
    • 3: massive deformity or canker, greater than 50% of the basal area or greater than 50% of the main axis length
11. rot: severity scale for any rot present
    • 1: small rotting area, smaller in area than a square of DBH x DBH in shape
    • 2: big rotting area, greater in area than a square of DBH x DBH in shape
    • 3: massive rotting, affecting more than 50% of the basal area or more than 50% of the main axis length
12. Lianas: severity of liana infestation
    • 0: lianas absent
    • 1: up to 25% of the tree crown covered by lianas
    • 2: 26-50% liana cover
    • 3: 51-75% liana cover
    • 4: 76-100% liana cover
13. DWR: Boolean for dead trees if they have resprouted below DBH
14. Notes: any field notes about the tree