Leaf area index of the deciduous forest on WS1 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 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 1998 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
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.
Occasional missing values throughout the data set resulted from
disturbances to the collectors.
In 2011 all the collectors from each plot were pooled for analysis of
LAI/
