Data description: Leaf area index of the deciduous forest west of WS6
at Hubbard Brook is measured annually on the basis of leaf litter
collections as detailed in the dataset "Fine Litter". Twelve
to fifteen litter traps are positioned randomly in four large sampling
plots (ca. 0.5 ha area) arranged along the elevation gradient in the
Bear Brook watershed. These plots are also locations where soil
microbial activity and other measurements are conducted. All litter
traps are raised about 1.5 m above ground level to discourage blow in
of leaf litter which was observed to be a bias early in the study.
Sampling design. The design for leaf litter collections is stratified
random with plot locations representing elevation zones as defined in
forest vegetation sampling, soil solutions and soil microbial activity
measurements.
Plot locations: These are identical to those in the fine litter
metadata.
These data are revised compared to earlier posted ("fine
litter") and published (Battles et al. 2015) data because a
correction of area per leaf estimates for the species and plots was
necessary.
From 1993 to 2012 LAI values are based on leaf litter counts for
November litterfall collection. Beginning in 2013 LAI values include
leaf litter that came down in outside of the fall season.
Area per leaf values for the various species differ among elevations,
and mean values for each species and plot represent the average for
two years of collection (2012 and 2019).
These values are contained in the fine litter data file. Area per leaf
values may differ among years, but additional sampling will be
necessary to quantify any such differences.
There are some missing data. Specifically, leaf litter sorting was not
conducted in the "Low" and "Upper" plots in 2011,
and sporadic missing values throughout the data set resulted from
disturbances to the collectors.
