Dataset DOI: 10.5061/dryad.83bk3jb74

Description of the data and file structure

These are the data associated with a project testing how forest structure impacts understory microclimate and fuel moisture content in two forests of the northeastern US. The datasets include forest structure measured from traditional forest inventories and terrestrial laser scanning, understory microclimate measurements of temperature and relative humidity, as well as repeated measurements of fuel moisture. These measurements took place at 24 plots across two locations in the summer of 2023.

Files and variables

Note: missing values indicated as "NA".

Note on plot ID nomenclature: P = Penobscot, Z = Zealand; A = open canopy, B = intermediate canopy, C = closed canopy. EXAMPLE: PC2 = the 2nd closed canopy plot at the Penobscot Experimental Forest. Plot Locations: Penobscot Experimental Forest in Bradley, ME; Zealand site near Zealand campground in the White Mountain National Forest near Twin Mountain, NH.

Note on units: all heights are recorded in meters, and all temperatures are recorded in degrees Celsius.

File: microclimate.csv

Description: These data contain hourly, daily, and seasonal summaries of microclimate variables measured at all plots.

Variables

• Site_ID = plot ID. See above note on plot ID nomenclature.
• Day = date as mm/dd/yyyy
• Date.Time = date and time as mm/dd/yyyy hh:mm:ss AM/PM
• AirT = hourly air temperature at Date.Time
• AirRH = hourly relative humidity at Date.Time
• VPD = hourly vapor pressure deficit at Date.Time. Calculated from relative humidity.
• Tmax.day = daily maximum air temperature for given Day
• Tmin.day = daily minimum air temperature for given Day
• Tmean.day = daily mean air temperature for given Day
• DTR = daily temperature range for given Day, calculated as Tmax.day - Tmin.day
• RHmin.day = daily minimum relative humidity for given Day
• VPDmax.day = daily maximum vapor pressure deficit for given Day
• Tmax.mean = mean daily maximum air temperature for entire study period (7/7/2023-9/6/2023)
• Tmin.mean = mean daily minimum air temperature for entire study period (7/7/2023-9/6/2023)
• Tmean.mean = mean daily mean air temperature for entire study period (7/7/2023-9/6/2023)
• DTR.mean = mean daily temperature range for entire study period (7/7/2023-9/6/2023)
• RHmin.mean = mean daily minimum relative humidity for entire study period (7/7/2023-9/6/2023)
• VPDmax.mean = mean daily maximum vapor pressure deficit for entire study period (7/7/2023-9/6/2023)
• Location = plot location at Penobscot Experimental Forest of Zealand in the White Mountain National Forest
• FMC.sumby = refers to a particular FMC measurement for subsetting data. Examples: PEF1 = first FMC measurement at PEF; ZEL2 = second FMC measurement at Zealand
• Tmax.FMC = mean daily maximum air temperature for 5 days prior to FMC measurement denoted in "FMC.sumby"
• Tmean.FMC = mean daily mean air temperature for 5 days prior to FMC measurement denoted in "FMC.sumby"
• Tmin.FMC = mean daily minimum air temperature for 5 days prior to FMC measurement denoted in "FMC.sumby"
• DTR.FMC = mean daily temperature range for 5 days prior to FMC measurement denoted in "FMC.sumby"
• RHmin.FMC = mean daily minimum relative humidity for 5 days prior to FMC measurement denoted in "FMC.sumby"
• VPDmax.FMC = mean daily maximum vapor pressure deficit for 5 days prior to FMC measurement denoted in "FMC.sumby"

File: tfi_plotmetrics.csv

Description: These data contain plot-level forest inventory summaries from fieldwork conducted at all plots.

Variables

• Site_ID = plot ID. See above note on plot ID nomenclature.
• BAPH = basal area per hectare (square meters per hectare) of the plot
• TPH = trees per hectare of the plot
• PCSW = percent softwood basal area of the plot
• BAPA = basal area per acre (sq. feet per acre) of the plot
• TPA = trees per acre of the plot
• Canopy_openness = canopy openness measured with spherical densiometer in leaf-on conditions
• Location: Penobscot = Penobscot Experimental Forest; Zealand = Zealand site near Twin Mountain, NH.

File: fuelmoisture.csv

Description: These data contain fuel moisture content of premade fuel sticks measured in the field.

Variables

• Stick_ID = unique numerical fuel stick identifier
• Date = date as mm/dd/yyyy
• Time = time as hh:mm
• Site_ID = plot ID. See above note on plot ID nomenclature.
• Weight = field mass in grams
• Collection = round of collection
• Dry_weight = oven-dried mass in grams
• FMC = fuel moisture content, calculated as (field mass - dry mass) / dry mass, expressed as a percent

File: tls_metrics.csv

Description: These data contain metrics generated from terrestrial laser scanner Leica BLK360. Variables represent mean values for each plot location clipped to 10m radius.

Variables

• Site_ID = plot ID. See above note on plot ID nomenclature.
• per_gap = Gap fraction of returns
• h_zq5 = 5th percentile of height distribution of returns
• h_zq35 = 35th percentile of height distribution of returns
• h0_10_l1_median = Median of 10-hour fuels at height 0.001-0.3m
• h_l3_per = Percent of returns recorded at height 1-3m
• hr0_10_l1_cnt = Number of returns for 10-hr fuels at height 0.001- 0.3m

Code/software

All analyses were run in R using RStudio (ver. 4.2.3, R Core Team 2023; RStudio Team 2023), and models were generated using packages nlme (Pinheiro et al. 1999) and VSURF (Genuer et al. 2013).

Access information

Data was derived from the following sources:

The datasets include forest structure measured from traditional forest inventories and terrestrial laser scanning, understory microclimate measurements of temperature and relative humidity, as well as repeated measurements of fuel moisture.