Fig 1.
A: Location of the APB (red triangle). B. Locations of coring sites (stars) and selected labeled landmarks on the western outskirts of Albany, New York. STU: Stump Pond coring site. APB1: Wetland coring site showing paleo-dune topography. PSB: Poplar Street Bog coring site [4]. Yellow cross-hatching represents property of the Albany Pine Bush Preserve. (base imagery from [6], accessed 5 April, 2024).
Table 1.
Radiocarbon ages of samples and modern coretop date from the STU (Stump Pond) and APB1 (wetland) cores.
Maximum, minimum, and median calibrated 2-σ age ranges shown here were calculated with CALIB version 8.2 [19]. For the APB1-B core, the sample depths are listed as within-core depths with total combined depths in parentheses. “B.P.” refers to years before A.D. 1950. The age obtained for the 5 cm sample in APB1-B (italics) was considered to be an outlier and was not included in the APB1 age-depth model. Not applicable is denoted by n.a. for the APB1 coretop.
Fig 2.
Age-depth models for the STU and APB1 cores.
The time scales spanning ca. 13,000 cal yr B.P. to the present were obtained using the “rbacon” package in R [18]. Probability ranges of the radiocarbon dates are shown in purple. The central red dashed lines shows the ‘best” models based on the weighted mean age. The outer dashed lines denote 95% confidence levels.
Fig 3.
Pollen and charcoal profiles from core STU (ca. 13,000–7200 cal yr B.P.).
Values are given as percentages of total terrestrial pollen grains and fern spores. Depths and calibrated ages of sediment subsamples are indicated along the left margin. Zonation was performed using CONISS with significance tested by a broken stick model. Interpolated charcoal influx units are in μm2/cm2yr.
Fig 4.
Pollen and charcoal profiles from wetland core APB1 (ca. 6400 cal yr B.P. to present).
Values are given as percentages of total terrestrial pollen grains and fern spores. Depths and calibrated ages of peat subsamples are indicated along the left margin. Interpolated charcoal influx units are in μm2/cm2yr.
Fig 5.
Principal components analysis results for core STU.
Left: Plots of first and second PCA axes versus time. Right: The biplot for the first two principal components shows taxa (arrows) and samples assigned to four pollen zones with CONISS (shapes). Arrow: Zone 4 samples (circled) were positioned off the scale to the lower left (PC1 values -1.1 to -1.4; PC2 values ca. -1.6).
Fig 6.
Principal components analysis results for core APB1.
Left: Plots of first and second PCA axes versus time. Right: The biplot for the first two principal components shows taxa (arrows) and samples assigned to four pollen zones with CONISS (shapes).
Fig 7.
STU fire record for 13,000–7,000 cal yr B.P.
(a) Plot of the number of raw charcoal particles per sample. (b) Plot of the smoothed signal to noise index (SNI), together with a red line at 3, the SNI cut-off. (c) Plot of the interpolated charcoal accumulation rate (μm2·cm-2·yr-1) record (black bars). Local fire peaks are marked by red crosses and pink vertical lines. The grey line shows background charcoal (BCHAR) and the red line marks the 95% threshold of the Gaussian noise models. (d) Plot of fire return intervals (FRIs). The blue transparent rectangles denote where the SNI < 3, where results should be treated with caution.
Fig 8.
APB1 fire record for 6,400–500 cal yr B.P.
(a) Plot of the number of raw charcoal particles per sample. (b) Plot of the smoothed signal to noise index (SNI), together with a red line at 3, the SNI cut-off. (c) Plot of the interpolated charcoal accumulation rate (μm2·cm-2·yr-1) record (black bars). Local fire peaks are marked by red crosses and pink vertical lines. The grey line shows background charcoal (BCHAR) and the red line marks the 95% threshold of the Gaussian noise models. (d) Plot of fire return intervals (FRIs). The blue transparent rectangles denote where the SNI < 3, where results should be treated with caution.
Fig 9.
Vegetation assemblages and fire activity in the Albany Pine Bush region during the last ca. 13,000 years.
Solid vertical lines represent the temporal gap between the records from the STU and APB1 coring sites. Dotted vertical line represents the period in which the APB1-A and APB1-B records meet. Solid circles represent significant peaks of fire activity (see Figs 7 and 8).