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This data package is comprised of three datasets all pertaining to two dominant palmetto species, Serenoa repens and Sabal etonia, at Archbold Biological Station in south-central Florida. The first dataset, palmetto_data, contains survival and growth data across multiple years, habitats and experimental treatments. The second dataset, seedlings_data, follows the fate of marked putative palmetto seedlings in the field to assess survivorship and growth. The final dataset, harvested_palmetto_data, contains size data and estimated dry mass (biomass in grams) of 33 destructively harvested palmetto plants (17 S. repens and 16 S. etonia) of varying sizes and across habitats. Thirty-two of these were used to calculate estimated biomass, using regression equations, for palmettos sampled in the palmetto_data. Below we summarize experimental setup and data collected for each dataset.

Palmetto data

Demographic data were collected as three separate components. The first component compared growth among habitats. Starting in 1981, equal numbers of both palmetto species were marked across scrubby flatwoods (oak scrub) and flatwoods habitats (3 sites per habitat) for a total of 240 marked plants. These habitats had not burned within the last decade, but historically had experienced a natural fire return interval of 5 - 20 years prior to this studies initiation. The second component added an additional 400 palmettos (200 of each species), which were marked in sand pine scrub (n = 200) in 1985 and sandhill habitat (n = 200) in 1989 on Archbold's Red Hill. At the time of this project's initiation, all Red Hill management units were last burned in 1927 and were considered long unburned. Part of Archbold's management plan included restoring fire into some management units while leaving others long unburned to serve as reference units. Therefore, for our second component, we were able to create a 2x2 factorial design using habitat types on Red Hill and fire management as factors, with 100 palmettos in each category (50 of each species). The third component involved an experiment to examine the factorial effects of clipping and fertilizing on palmetto flowering. We marked 300 palmettos (150 of each species), all in sand pine scrub habitat on Red Hill, and used the 100 palmettos marked in 1985 as controls.

Annual data measures included height, canopy length and width (all in cm), number of new and green leaves and flowering scapes. Data were collected continuously (not for all variables or sites) from 1981 through 1997 then again in 2001 and 2017. Data collection is ongoing at 5-year intervals. Data on the 100 plants in the experimental sandhill on Red Hill were not collected in 2017 due to the removal of marked stakes from roller chopping of the site as part of more recent sandhill restoration efforts. A subset of the plants in the clipping and fertilizing experiment were lost in 2013 when a plow line was established to stop the spread of a wildfire. The locations of all remaining plants were taken in 2017 using a Trimble GPS unit and are included as a separate data file (palmetto_location_data) and shapefile (palmetto_shape).

Seedling data

In January 1989, we marked 100 putative seedlings in flatwoods habitats and 87 in scrubby flatwoods habitats. Putative seedlings typically cannot be identified using morphology as either S. repens or S. etonia so sample sizes of each are unknown. Annual data recorded included survival, standing height (cm) and maximum crown diameter (cm). In 1991, we started measuring basal stem diameter (cm) with calipers. During annual visits, we noted if the species could be identified as S. repens or S. etonia. Data were collected continuously starting in 1989 through 1997, then again in 2001 and 2008. Data collection is not ongoing for this dataset.

Harvested Palmetto data

Thirty-three palmettos, 17 S. repens and 16 S. etonia, were destructively harvested at three different sites, from two habitats (scrubby flatwoods and sand pine scrub) in 1985. Basic size measures as taken for palmetto demography data were recorded including height, canopy length and width (all in cm) and the number of green leaves. Additional data measures were recorded on the largest leaf blade including maximum length and width of the palmetto leaf and petiole length and width. Finally, basal diameter at the ground level was recorded. Only 32 palmettos were used to develop biomass regressions (17 S. repens and 15 S. etonia).

Biomass is the estimated dry mass (g) of each harvested palmetto. Fresh palmettos were divided into leaf and stem (both above- and below-ground), but roots were not harvested since they grow to depths of several meters, making recovery of all root tissues virtually impossible for fresh-mass determination. Subsamples of fresh mass were oven dried at 80C to constant mass for estimation of dry mass equivalent, which in turn was used to estimate the dry mass of the harvested palmettos.