This dataset includes every pin-hit recorded from 19 1m x 1m point frame plots of tall Betula nana and Salix pulchra canopies sampled at the Toolik Field Station, AK the summer of 2012. Twenty-five evenly spaced holes within the plot were sampled for each point frame for which the height and species was recorded for each leaf, stem, or plant that intersected the pin when lowered perpendicular to the ground. Non-woody species were grouped into functional groups (e.g. forb, graminoid, moss) and not identified to species.
Maximum canopy height measurements for deciduous shrub canopies sampled for both 1m x 1mc hamber flux polots (n=14) and point frame plots (n=19) in the summer of 2012 near LTER shrub plots at Toolik Lake, AK. The canopies were dominated either by Salix pulchra or Betula nana species, and plot locations were preferentially selected for tall canopies (height > 75 cm). The methods for the chamber flux and point frames are outlined here briefly, though the data from these measurements are contained in separate files.
Summary of three methods used to estimate the Leaf Area Index (LAI) of 19 1m x 1m plots sampled with a point frame near the LTER Shrub plots at the Toolik Field Station in AK the summer of 2012. The methods used were: (1) exponential relationship between LAI and NDVI as measured above the canopy with a Unispec spetroradiometer; (2) Delta-T SunScan canopy analyzer held at 5 cm above the ground under both direct and diffuse light conditions; (3) pin-drop point frame tequnique. Where values have been averaged (such as for the NDVI and SunScan measurements), the standard deviation is given.
Leaf area index (LAI) measurements were taken with the Delta-T SunScan wand every 15 cm from the ground to above the canopy under both direct and diffuse light. conditions The data includes all outputs from the SunScan wand: time of measurement, transmitted light, spread of PAR sensors, beam fraction, and zenith angle.
Total and individual subsample species percent cover data for all plots where flux or point frame measurements were made in 2012 IVO the LTER Shrub vegetation plots at Toolik Field Station. All plots sampled were dominated either by B. nana or S. pulchra canopies. Cover estimates were made for the five most dominate functional groups using a 1m x 1m grid with 20cm2 blocks with each square representing four percent of the total area. Percentages represent absolute cover so do not sum to 100%.
This file contains irradiance (PAR) and diffuse light data logged from a beam fraction (BF3) sensor near Toolik Lake, Alaska during the summer of 2012. The data comes from a compilation of automated datalogger readings as well as measurements taken during the field season in conjunction with the Delta-T SunScan wand to measure PAR in tall shrub canopies dominated by Betula nana or Salix pulchra species. The sensor was leveled and mounted to a 2m tripod in each location, and programmed to record instantaneous readings in 30 second to 5 minute intervals.
"2012_GS_PFandCH_GPS" contains GPS locations of all datalogger, 1m x 1m chamber flux and point frame plots sampled IVO Toolik Field Station in Alaska during the summer of 2012. The sorting variables (YEAR, DATE, SITE, GROUP, PLOT, TREAT, PLOT SIZE) are identical to those in other files with data collected that season. The main purpose of this file is for reference and as an aid in interpretation of data analyses and among-site comparisons.
Within-canopy PAR was measured with a Delta-T SunScan wand every 15 cm from the ground to above the canopy under both direct and diffuse light. The data includes all outputs from the SunScan wand: time of measurement, spread of PAR sensors, total irradiance, total diffuse light, and individual outputs of 64-PAR sensors on the SunScan wand. These measurements were taken for 1m x 1m chamber flux (n=14) and point frame (n=19) plots as well as sites four montitored remotely by PAR sensors located above, within, and below shrub canopies.