Harvard Forest

Data Archive

HF257

Long-Term Impacts of the Hemlock Woolly Adelgid on Forest Carbon at Harvard Forest 2008-2011

Related Publications

Data

• hf257-01: soil temperature sensor 1 at Burnham Brook (preview)
• hf257-02: soil temperature sensor 2 at Burnham Brook (preview)
• hf257-03: soil temperature at Harvard Conservation Trust (preview)
• hf257-04: soil moisture (preview)
• hf257-05: soil respiration (preview)
• hf257-06: black birch sapling allometry (preview)
• hf257-07: tree diameters at breast height (preview)
• hf257-08: sapling diameters at breast height at CT site (preview)
• hf257-09: microbial enzyme activity (preview)
• hf257-10: foliar decomposition (preview)
• hf257-11: litterfall (preview)
• hf257-12: coarse woody debris carbon and nitrogen (preview)
• hf257-13: wood carbon and nitrogen (preview)
• hf257-14: green foliage nitrogen and carbon (preview)
• hf257-15: litter foliage carbon and nitrogen (preview)
• hf257-16: soil bulk density (preview)
• hf257-17: woody debris (preview)
• hf257-18: fine woody debris carbon and nitrogen (preview)
• hf257-19: root carbon and nitrogen (preview)
• hf257-20: soil carbon and nitrogen (preview)
• hf257-21: root biomass (preview)
• hf257-22: rock fraction (preview)
• hf257-23: relative growth rate (preview)
• hf257-24: tree rings (preview)
• hf257-25: litterfall rate (preview)

Overview

• Lead: Poliana Raymer, Adrien Finzi
• Investigators: David Orwig
• Contact: Information Manager
• Start date: 2008
• End date: 2011
• Status: complete
• Location: Prospect Hill Tract (Harvard Forest), Simes Tract (Harvard Forest), Harvard Conservation Trust (Harvard MA), Burnham Brook Preserve (East Haddam CT)
• Latitude: +41.47 to +42.53 degrees
• Longitude: -72.32 to -71.53 degrees
• Elevation:
• Datum: WGS84
• Taxa: Adelges tsugae (hemlock woolly adelgid), Betula lenta (black birch), Tsuga canadensis (eastern hemlock)
• Release date: 2023
• Language: English
• EML file: knb-lter-hfr.257.6
• DOI: digital object identifier
• EDI: data package
• DataONE: data package
• Related links:
• Study type: short-term measurement
• Research topic: invasive plants, pests and pathogens; soil carbon and nitrogen dynamics
• LTER core area: primary production, organic matter movement, disturbance patterns
• Keywords: biomass, carbon, coarse woody debris, decomposition, hemlock, hemlock woolly adelgid, litterfall, net ecosystem production, nitrogen, soil moisture, soil respiration, soil temperature
• Abstract:

  The abundance of eastern hemlock (Tsuga canadensis) in eastern US forests has declined since the 1950s owing to the introduction of the non-native insect, hemlock woolly adelgid (HWA, Adelges tsugae). In southern New England, eastern hemlock is being replaced by the deciduous tree species, black birch (Betula lenta). To date there is little understanding of whether hemlock loss will fundamentally alter ecosystem C balance and component fluxes.

  In this study, we use a comparative approach to study potential changes in C fluxes and storage and N cycling associated with HWA-induced hemlock decline and replacement. The stands include primary- and secondary-growth hemlock forests (230 and 132 years old, respectively), recently disturbed stands (5 and 18 years old) that now have rapidly growing black birch saplings, and a mature black birch stand of age similar to the second-growth hemlock stand. We addressed the question of whether the quantity and distribution of C pools in black birch forests are the same as those found in the hemlock stands they replace and, if so, over what time scales.

  We found that if HWA did not infest hemlock stands in central MA, C stocks in these secondary stands could still increase by at least 30% over a period of 100 years. Girdling, intended to simulate HWA infestation, resulted in a large transfer of C from live biomass to coarse woody debris five years after treatment, but had little effect on total ecosystem C content. A former hemlock stand killed by HWA and now dominated by black birch saplings also had a large pool of highly decayed CWD and a rapidly aggrading C pool in live biomass. C pools in biomass in a mature, secondary growth black birch stand 135 years since pastureland abandonment were as large as those in a primary-growth hemlock stand 235 years of age.

  We also found that aboveground net primary production was higher in the aggrading black birch stand and significantly so at 18-years post-HWA compared to the secondary-hemlock stand it would likely replace. Rapid forest regrowth was accompanied by significantly higher rates of N uptake from the soil but also higher N-use efficiency because most of the N taken up from the soil was allocated to the production of wood with a high C-to-N ratio. In contrast to patterns of aboveground production, the rate of soil respiration was lowest in the young stands and not significantly different from the second-growth hemlock stand, suggesting little net effect of stand replacement on soil C efflux. The leaf litter decomposition study showed that black birch litter decomposed more rapidly than hemlock litter but that there was no effect of stand type on the rate of decomposition. Analyses of extracellular microbial exoenzyme activity painted a more nuanced pattern of variation among stands, with fine root biomass the only weakly explanatory variable.

  Based on this analysis, it appears that ecosystem C storage is resilient to the loss of hemlock because of vigorous regrowth by black birch. These results suggest that forests affected by HWA in southern New England will remain a sink for atmospheric CO2 despite reorganization of stand structure and species composition.

• Methods:

  For detailed methods, please see:

  Raymer, P. C. L., D. A. Orwig, and A. C. Finzi. 2013. Hemlock loss due to the hemlock woolly adelgid does not affect ecosystem C storage but alters its distribution. Ecosphere 4(5):63. http://dx.doi.org/10.1890/ES12-00362.1

  Finzi, A. C., P. C. L. Raymer, M.-A. Giasson, and D. A. Orwig. 2014. Net primary production and soil respiration in New England hemlock forests affected by the hemlock woolly adelgid. Ecosphere 5(8):98. http://dx.doi.org/10.1890/ES14-00102.1

• 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.

• 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: Raymer P, Finzi A. 2023. Long-Term Impacts of the Hemlock Woolly Adelgid on Forest Carbon at Harvard Forest 2008-2011. Harvard Forest Data Archive: HF257 (v.6). Environmental Data Initiative: https://doi.org/10.6073/pasta/3423acc2e3c44eea8f6a810dc9010820.

Detailed Metadata

hf257-01: soil temperature sensor 1 at Burnham Brook

1. datetime: date and time of measurement
2. year: year of measurement
3. month: month of measurement
4. day: day of measurement
5. date: date of measurement
6. time: time of measurement
7. tsoil: soil temperature (sensor #1) at 5 cm depth at the Burham Brook, CT site (unit: celsius / missing value: NA)

hf257-02: soil temperature sensor 2 at Burnham Brook

1. datetime: date and time of measurement
2. year: year of measurement
3. month: month of measurement
4. day: day of measurement
5. date: date of measurement
6. time: time of measurement
7. tsoil: soil temperature (sensor #2) at 5 cm depth at the Burnham Brook, CT site (unit: celsius / missing value: NA)

hf257-03: soil temperature at Harvard Conservation Trust

1. datetime: date and time of measurement
2. year: year of measurement
3. month: month of measurement
4. day: day of measurement
5. date: date of measurement
6. time: time of measurement
7. tsoil: soil temperature at 5 cm depth at the Harvard Conservation Trust site (unit: celsius / missing value: NA)

hf257-04: soil moisture

1. date: date of measurement
2. year: year of measurement
3. doy: day of measurement, Julian day (unit: nominalDay / missing value: NA)
4. hour: hour of measurement (unit: nominalHour / missing value: NA)
5. og.5cm: soil moisture at 5 cm depth at the hemlock old-growth plot (unit: dimensionless / missing value: NA)
6. g2.5cm: soil moisture at 5 cm depth at the hemlock second-growth plot (unit: dimensionless / missing value: NA)
7. gdl.5cm: soil moisture at 5 cm depth at the hemlock girdled plot (unit: dimensionless / missing value: NA)
8. ct.5cm: soil moisture at 5 cm depth at the post-hemlock woolly adelgid infestation (Connecticut) plot (unit: dimensionless / missing value: NA)
9. ht.5cm: soil moisture at 5 cm depth at the mature black birch plot (Harvard Conservation trust) (unit: dimensionless / missing value: NA)
10. og.15cm: soil moisture at 15 cm depth at the hemlock old-growth plot (unit: dimensionless / missing value: NA)
11. g2.15cm: soil moisture at 15 cm depth at the hemlock second-growth plot (unit: dimensionless / missing value: NA)
12. gdl.15cm: soil moisture at 15 cm depth at the hemlock girdled plot (unit: dimensionless / missing value: NA)
13. ct.15cm: soil moisture at 15-cm depth at the post-hemlock woolly adelgid infestation (Connecticut) plot (unit: dimensionless / missing value: NA)
14. ht.15cm: soil moisture at 15 cm depth at the mature black birch plot (Harvard Conservation trust) (unit: dimensionless / missing value: NA)

hf257-05: soil respiration

1. datetime: date and time of measurement
2. year: year of measurement
3. month: month of measurement
4. day: day of measurement
5. date: date of measurement
6. time: time of measurement
7. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
8. plot: plot number
9. collar: soil respiration collar number
10. rsoil: soil respiration (μmol CO2/m2/s) (unit: micromolePerMeterSquaredPerSecond / missing value: NA)
11. tsoil: soil temperature at 5 cm depth measured adjacent to the collar (unit: celsius / missing value: NA)

hf257-06: black birch sapling allometry

1. sapling: black birch sapling number
2. stem.length: stem length (unit: meter / missing value: NA)
3. dbh: diameter at breast height (unit: centimeter / missing value: NA)
4. leaf.mass: leaf mass (unit: gram / missing value: NA)
5. wood.mass: wood mass (unit: gram / missing value: NA)
6. total.mass: total mass (unit: gram / missing value: NA)

hf257-07: tree diameters at breast height

1. site: site
   • OG: old-growth hemlock
   • SG: second-growth hemlock
   • GDL: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust
2. plot: plot number
3. species: species
   • ACPE: Acer pensylvanicum
   • ACRU: Acer rubrum
   • BEAL: Betula alleghaniensis
   • BELE: Betula lenta
   • BEPA: Betula papyrifera
   • CADE: Castanea dentata
   • CAGL: Carya glabra
   • CAOV: Carya ovata
   • FAGR: Fagus grandifolia
   • FRAM: Fraxinus americana
   • FRNI: Fraxinus nigra
   • HAVI: Hamamelis virginiana
   • KALA: Kalmia latifolia
   • OSVI: Ostrya virginiana
   • PIST: Pinus strobus
   • QUAL: Quercus alba
   • QUBI: Quercus bicolor
   • QURU: Quercus rubra
   • SOAM: Sorbus americana
   • TSCA: Tsuga canadensis
4. dbh: diameter at breast height (unit: centimeter / missing value: NA)

hf257-08: sapling diameters at breast height at CT site

1. year: year of measurement
2. plot: plot number
3. transect: transect number (1 x 30 m transects)
4. species: species
   • BELE: Betula lenta
5. dbh: diameter at breast height (unit: centimeter / missing value: NA)

hf257-09: microbial enzyme activity

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. plot: plot number
3. horizon: soil horizon
   • Organic: organic
   • Mineral: mineral
4. depth: depth of measurement, cm
5. ag: α-1,4-glucosidase activity (μmol substrate converted/g soil/hour) (unit: micromolePerGramPerHour / missing value: NA)
6. bg: β-1,4-glucosidase activity (μmol substrate converted/g soil/hour) (unit: micromolePerGramPerHour / missing value: NA)
7. cbh: cellobiohydrolase activity (μmol substrate converted/g soil/hour) (unit: micromolePerGramPerHour / missing value: NA)
8. ap: acid phosphatase activity (μmol substrate converted/g soil/hour) (unit: micromolePerGramPerHour / missing value: NA)
9. nag: β-N-acetylglucosaminidase activity (μmol substrate converted/g soil/hour) (unit: micromolePerGramPerHour / missing value: NA)
10. phenox: phenol oxidase activity (μmol substrate converted/g soil/hour) (unit: micromolePerGramPerHour / missing value: NA)
11. perox: peroxydase activity (μmol substrate converted/g soil/hour) (unit: micromolePerGramPerHour / missing value: NA)

hf257-10: foliar decomposition

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. species: tree species of the litter used in the decomposition bags
   • BELE: black birch leaves
   • TSCA: eastern hemlock needles
3. plot: plot number
4. replicate: replicate number
5. deployment: date the bags were inserted in the ground
6. original.wt: litter weight initially placed in the bags (unit: gram / missing value: NA)
7. harvest1: date of first harvest of bags
8. harvest1.wt: weight of litter remaining in the bags after the first harvest (unit: gram / missing value: NA)
9. harvest2: date of second harvest of bags
10. harvest2.wt: weight of litter remaining in the bags after the second harvest (unit: gram / missing value: NA)
11. harvest3: date of third harvest of bags
12. harvest3.wt: weight of litter remaining in the bags after the third harvest (unit: gram / missing value: NA)
13. harvest4: date of fourth harvest of bags
14. harvest4.wt: weight of litter remaining in the bags after the fourth harvest (unit: gram / missing value: NA)

hf257-11: litterfall

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. plot: plot number
3. replicate: litter basket number
4. date: sample collection date
5. bele: dry mass of black birch litter collected (unit: gram / missing value: NA)
6. tsca: dry mass of eastern hemlock litter collected (unit: gram / missing value: NA)
7. acru: dry mass of red maple litter collected (unit: gram / missing value: NA)
8. acsa: dry mass of sugar maple litter collected (unit: gram / missing value: NA)
9. quru: dry mass of red oak litter collected (unit: gram / missing value: NA)
10. qual: dry mass of white oak litter collected (unit: gram / missing value: NA)
11. pist: dry mass of white pine litter collected (unit: gram / missing value: NA)
12. others: dry mass of litter from other species collected (unit: gram / missing value: NA)

hf257-12: coarse woody debris carbon and nitrogen

1. species: tree species
   • BELE: black birch
   • TSCA: eastern hemlock
2. type: type of coarse woody debris
3. decay: decay class
   • 1: solid wood, recently fallen, bark and twigs present
   • 2: solid wood, significant weathering, branches present
   • 3: wood not solid, bark may be sloughing but nail still must be pounded into wood
   • 4: wood sloughing and/or friable, nail may be forcibly pushed into wood
   • 5: wood friable, barely holding shape, nail may be easily pushed into wood
4. n: nitrogen content of coarse woody debris (unit: dimensionless / missing value: NA)
5. c: carbon content of coarse woody debris (unit: dimensionless / missing value: NA)

hf257-13: wood carbon and nitrogen

1. species: tree species
   • ACRU: red maple
   • ACSA: sugar maple
   • BELE: black birch
   • PIST: white pine
   • QUAL: white oak
   • QURU: red oak
   • TSCA: eastern hemlock
2. replicate: replicate number
3. n: nitrogen content of wood (unit: dimensionless / missing value: NA)
4. c: carbon content of wood (unit: dimensionless / missing value: NA)

hf257-14: green foliage nitrogen and carbon

1. species: tree species
   • BELE: black birch
   • PIST: white pine
   • QUAL: white oak
   • QURU: red oak
   • TSCA: eastern hemlock
2. replicate: replicate number
3. n: nitrogen content of green foliage (unit: dimensionless / missing value: NA)
4. c: carbon content of green foliage (unit: dimensionless / missing value: NA)

hf257-15: litter foliage carbon and nitrogen

1. species: tree species
   • ACRU: red maple
   • ACSA: sugar maple
   • BELE: black birch
   • PIST: white pine
   • QUAL: white oak
   • QURU: read oak
   • TSCA: eastern hemlock
2. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
3. n: nitrogen content of litter foliage (unit: dimensionless / missing value: NA)
4. c: carbon content of litter foliage (unit: dimensionless / missing value: NA)

hf257-16: soil bulk density

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. plot: plot number
3. replicate: replicate number
4. horizon: soil horizon (organic or mineral)
5. sample.depth: sample depth (cm)
6. date: date of collection
7. sample.wt: weight of sample (wet soil) (unit: gram / missing value: NA)
8. dw.ratio: dry:wet ration (unit: dimensionless / missing value: NA)
9. bulk.density: soil bulk density (unit: gramsPerCubicCentimeter / missing value: NA)
10. soil.mass: mass of soil per unit surface area (unit: kilogramsPerSquareMeter / missing value: NA)

hf257-17: woody debris

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. plot: plot number
3. cwd: coarse (greater than 10cm diameter) woody debris carbon mass per unit surface area (unit: gramsPerSquareMeter / missing value: NA)
4. swd: small (1-10 cm diameter) woody debris carbon mass per unit surface area (unit: gramsPerSquareMeter / missing value: NA)
5. fwd: fine (less than 1cm diameter) woody debris carbon mass per unit surface area (unit: gramsPerSquareMeter / missing value: NA)

hf257-18: fine woody debris carbon and nitrogen

1. species: tree species
   • BELE: black birch
   • TSCA: eastern hemlock
2. decay: decay class
   • 1: solid wood, recently fallen, bark and twigs present
   • 2: solid wood, significant weathering, branches present
   • 3: wood not solid, bark may be sloughing but nail still must be pounded into wood
   • 4: wood sloughing and/or friable, nail may be forcibly pushed into wood
   • 5: wood friable, barely holding shape, nail may be easily pushed into wood
3. n: nitrogen content of fine woody debris (unit: dimensionless / missing value: NA)
4. c: carbon content of fine woody debris (unit: dimensionless / missing value: NA)

hf257-19: root carbon and nitrogen

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. plot: plot number
3. pit: soil pit number
4. replicate: replicate number
5. horizon: soil horizon (organic or mineral)
6. depth: sample depth (cm)
7. diameter: root diameter
8. live.dead: live or dead roots
9. n: nitrogen content of roots (unit: dimensionless / missing value: NA)
10. c: carbon content of roots (unit: dimensionless / missing value: NA)

hf257-20: soil carbon and nitrogen

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. horizon: soil horizon (organic or mineral)
3. depth: sample depth (cm)
4. n: nitrogen content of roots (unit: dimensionless / missing value: NA)
5. c: carbon content of roots (unit: dimensionless / missing value: NA)

hf257-21: root biomass

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. horizon: soil horizon (organic or mineral)
3. depth: sample depth (cm)
4. diameter: root diameter
5. mass: dry root biomass (unit: gramsPerSquareMeter / missing value: NA)

hf257-22: rock fraction

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. pit: soil pit number
3. depth: sample depth (cm)
4. rocks: rock fraction (unit: dimensionless / missing value: NA)

hf257-23: relative growth rate

1. year.rel: year relative to the occurrence of hemlock woolly adelgid or girdling. For Gdl, Year 0 = 2005. For CT, Year 0 = 1992 (unit: number / missing value: NA)
2. gdl.diameter: average tree diameter at the girdled site, hardwoods only (unit: centimeter / missing value: NA)
3. gdl.annual.growth: average annual tree diameter growth at the girdled site, hardwoods only (unit: millimeter / missing value: NA)
4. gdl.relative.growth: average relative growth rate at the girdled site, hardwoods only (μm/yr/cm) (unit: dimensionless / missing value: NA)
5. gdl.se: standard error of average relative growth rate at the girdled site, hardwoods only (μm/yr/cm) (unit: dimensionless / missing value: NA)
6. ct.diameter: average tree diameter at the infested site (Connecticut), hardwoods only (unit: centimeter / missing value: NA)
7. ct.annual.growth: average annual tree diameter growth at infested site (Connecticut), hardwoods only (unit: millimeter / missing value: NA)
8. ct.relative.growth: average relative growth rate at the infested site (Connecticut), hardwoods only (μm/yr/cm) (unit: dimensionless / missing value: NA)
9. ct.se: standard error of average relative growth rate at the infested site (Connecticut), hardwoods only (μm/yr/cm) (unit: dimensionless / missing value: NA)
10. g2.diameter: average tree diameter at the hemlock second growth site, hardwoods only (unit: centimeter / missing value: NA)
11. g2.annual.growth: average annual tree diameter growth at the hemlock second growth site, hardwoods only (unit: millimeter / missing value: NA)
12. g2.relative.growth: average relative growth rate at the hemlock second growth site, hardwoods only (μm/yr/cm) (unit: dimensionless / missing value: NA)
13. g2.se: standard error of average relative growth rate at the hemlock second growth site, hardwoods only (μm/yr/cm) (unit: dimensionless / missing value: NA)

hf257-24: tree rings

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. plot: plot number
3. tree: tree identification number
4. species: tree species
   • ACRU: red maple
   • ACSA: sugar maple
   • BELE: black birch
   • PIST: white pine
   • QUAL: white oak
   • QURU: red oak
   • TSCA: eastern hemlock
5. dbh.2010: diameter at breast height in 2010 (unit: centimeter / missing value: NA)
6. ring.1980: ring width in 1980 (unit: micrometer / missing value: NA)
7. ring.1981: ring width in 1981 (unit: micrometer / missing value: NA)
8. ring.1982: ring width in 1982 (unit: micrometer / missing value: NA)
9. ring.1983: ring width in 1983 (unit: micrometer / missing value: NA)
10. ring.1984: ring width in 1984 (unit: micrometer / missing value: NA)
11. ring.1985: ring width in 1985 (unit: micrometer / missing value: NA)
12. ring.1986: ring width in 1986 (unit: micrometer / missing value: NA)
13. ring.1987: ring width in 1987 (unit: micrometer / missing value: NA)
14. ring.1988: ring width in 1988 (unit: micrometer / missing value: NA)
15. ring.1989: ring width in 1989 (unit: micrometer / missing value: NA)
16. ring.1990: ring width in 1990 (unit: micrometer / missing value: NA)
17. ring.1991: ring width in 1991 (unit: micrometer / missing value: NA)
18. ring.1992: ring width in 1992 (unit: micrometer / missing value: NA)
19. ring.1993: ring width in 1993 (unit: micrometer / missing value: NA)
20. ring.1994: ring width in 1994 (unit: micrometer / missing value: NA)
21. ring.1995: ring width in 1995 (unit: micrometer / missing value: NA)
22. ring.1996: ring width in 1996 (unit: micrometer / missing value: NA)
23. ring.1997: ring width in 1997 (unit: micrometer / missing value: NA)
24. ring.1998: ring width in 1998 (unit: micrometer / missing value: NA)
25. ring.1999: ring width in 1999 (unit: micrometer / missing value: NA)
26. ring.2000: ring width in 2000 (unit: micrometer / missing value: NA)
27. ring.2001: ring width in 2001 (unit: micrometer / missing value: NA)
28. ring.2002: ring width in 2002 (unit: micrometer / missing value: NA)
29. ring.2003: ring width in 2003 (unit: micrometer / missing value: NA)
30. ring.2004: ring width in 2004 (unit: micrometer / missing value: NA)
31. ring.2005: ring width in 2005 (unit: micrometer / missing value: NA)
32. ring.2006: ring width in 2006 (unit: micrometer / missing value: NA)
33. ring.2007: ring width in 2007 (unit: micrometer / missing value: NA)
34. ring.2008: ring width in 2008 (unit: micrometer / missing value: NA)
35. ring.2009: ring width in 2009 (unit: micrometer / missing value: NA)
36. ring.2010: ring width in 2010 (unit: micrometer / missing value: NA)

hf257-25: litterfall rate

1. site: site
   • OG: old-growth hemlock
   • 2G: second-growth hemlock
   • Gdl: girdled hemlock
   • CT: post-hemlock woolly adelgid infestation (Connecticut)
   • HT: black birch (Harvard Conservation Trust)
2. plot: plot number
3. bele: black birch litterfall rate from mid-October 2010 to early September 2011 (unit: gramsPerMeterSquaredPerYear / missing value: NA)
4. tsca: eastern hemlock litterfall rate from mid-October 2010 to early September 2011 (unit: gramsPerMeterSquaredPerYear / missing value: NA)
5. acru: red maple litterfall rate from mid-October 2010 to early September 2011 (unit: gramsPerMeterSquaredPerYear / missing value: NA)
6. acsa: sugar maple litterfall rate from mid-October 2010 to early September 2011 (unit: gramsPerMeterSquaredPerYear / missing value: NA)
7. quru: red oak litterfall rate from mid-October 2010 to early September 2011 (unit: gramsPerMeterSquaredPerYear / missing value: NA)
8. qual: white oak litterfall rate from mid-October 2010 to early September 2011 (unit: gramsPerMeterSquaredPerYear / missing value: NA)
9. pist: white pine litterfall rate from mid-October 2010 to early September 2011 (unit: gramsPerMeterSquaredPerYear / missing value: NA)
10. others: other species litterfall rate from mid-October 2010 to early September 2011 (unit: gramsPerMeterSquaredPerYear / missing value: NA)