uid=HFR,o=lter,dc=ecoinformatics,dc=org all public read doi:10.6073/pasta/1e05f22e37234fb6913d372b94768227 David Foster https://orcid.org/0000-0003-1171-3762 Jason McLachlan 2023 English

The long-term impact of human land-use is among the most important factors influencing the development of vegetation in New England, a region which experienced extensive agricultural clearance in the 19th century and subsequent reforestation during this century. We employed stand-level pollen stratigraphies and tree-ring chronologies to examine the post-settlement dynamics of hemlock stands which have never been pastured or plowed, representing among the least disturbed parts of the central Massachusetts landscape. Although the sites are currently dominated by large Tsuga canadensis individuals and give the impression of great age and stability, our results indicate that they have dynamic developmental histories driven by exogenous disturbance factors, including logging, forest pathogens, catastrophic wind disturbance, and fire. Sites containing pre-settlement pollen assemblages indicate stand compositions at this time which were substantially different from each other and from modern assemblages. Pollen assemblages similar to those of modern stands were not established in any of our sites until the 20th century and the mechanisms by which these assemblages arose was considerably different in each stand, indicating great flexibility of forest response to a variety of disturbance types.

dendrochronology human disturbance paleoecology succession vegetation dynamics LTER controlled vocabulary disturbance human-environment LTER core area Harvard Forest HFR LTER USA HFR default

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.

Creative Commons Zero v1.0 Universal https://spdx.org/licenses/CC0-1.0.html CC0-1.0 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf029 Prospect Hill Tract (Harvard Forest), Slab City Tract (Harvard Forest). Coordinates based on WGS84 datum. -72.20 -72.16 +42.55 +42.45 205 420 meter 1500 2000 genus Betula birch genus Castanea chestnut genus Pinus pine genus Quercus oak genus Tsuga hemlock complete Information Manager Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 hf-im@lists.fas.harvard.edu Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 (978) 724-3595 https://harvardforest.fas.harvard.edu

We recorded species, diameter at breast height, and crown class for all individuals greater than 2.5 cm in basal diameter in a 30 x30 m plot in each stand centered around the site of the humus monolith. General compositional records for each site since 1907 were obtained from Harvard Forest archival materials, and stem numbers and diameters measured in 1937 were available from 0.05-ha and 0.1-ha plots overlapping or adjacent to each of the current study sites. Disturbance histories for the town of Petersham and for the individual sites were compiled from a number of archival sources. We cored all stems greater than 2.5 cm dbh in each plot at the base and measured annual growth increments to the nearest 0.01 mm. A 30 x 30 cm humus monolith was removed from the center of each plot and was subsampled for pollen analysis at 1-2 cm intervals. Chronologies for the pollen records from Slab City IX and Slab City X were derived using parabolic curves fit through three pollen stratigraphic markers: European settlement (1730), marked by an increase in the agricultural weed species Ambrosia and Poaceae; the chestnut blight (1914), marked by a decline in Castanea pollen; and the uppermost assemblage (1995).

Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 (978) 724-3595 https://harvardforest.fas.harvard.edu https://ror.org/059cpzx98 pointOfContact 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. National Science Foundation LTER grants: DEB-8811764, DEB-9411975, DEB-0080592, DEB-0620443, DEB-1237491, DEB-1832210. hf029-01-sum.csv summary data hf029-01-sum.csv 1272 8e16ba8f2fc7a81e5e7ff4f3858f9bd8 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p02/hf029/hf029-01-sum.csv plot plot PH2 Prospect Hill II PH7 Prospect Hill VII SC9 Slab City IX SC10 Slab City X species species name Wp Pinus strobes hem Tsuga fg Fagus grandifolia rm Acer rubrum bb Betula lenta ro Quercus rubra yb Betula alleghaniensis fp Fraxinus pennsylvanica wa Fraxinus Americana pb Betula papyrifera density tree density (stems/ha) numberPerHectare 1 whole NA missing value basal.area tree basal area (m2/ha) meterSquaredPerHectare 0.01 real NA missing value 36 hf029-02-pollen.csv pollen hf029-02-pollen.csv 173150 0599ccf3e3ddbbd8200d8aa15e47809f 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p02/hf029/hf029-02-pollen.csv plot plot name PH2 Prospect Hill II PH7 Prospect Hill VII SC9 Slab City IX SC10 Slab City X depth depth in centimeters in the sediment column centimeter 0.1 real NA missing value taxa individual taxa taxa count number of pollen grains of individual taxa identified number 0.1 real NA missing value 7523 historical regional paleological