LOCATION DESCRIPTIONS
Fine Litterfall is collected at 4 different locations.
Watershed 1 Sites:
These sites are located along the W1 trail at the elevations provided
below. There are ten collectors per site arranged along two transects,
with five 0.097 m2 collectors on each transect. Collections on W1
began in 1997.
Low, hardwood – elevation 520 m
Mid, hardwood – elevation 600 m
Upper, hardwood – elevation 710 m
High, spruce/fir – elevation 740 m
Watershed 5 Sites:
Location and dimensions of collectors (leaf collection baskets) in W5
were changed after May 1993. Before 1993 collectors (43 x 43 cm) were
located in the twenty permanent vegetation plots. A map of these plots
is filed in Durham, NH with the data manager. After May 1993 new sites
and collectors (0.097 m2) were initiated. Twenty traps are positioned
randomly within four elevation zones, distributed with four collectors
in each of five grid cells in W5. Grid cell numbers refer to the W5
grid; the watershed is gridded into 25 x 25 m cells, the corners of
which are marked with orange poles, the pole in the northwest corner
bearing the grid cell number. Contact the data manager for the grid
cell map of W5.
Low, hardwood – elevation 530 m
Mid, hardwood – elevation 610 m
Upper, hardwood – elevation 690 m
High, hardwood – elevation 750 m
Bear Brook Sites:
West of W6: 0.097 m2 collectors are randomly situated along three 100
m long transects (325 degrees) which are approximately 25 m apart.
Originally 20 collectors per elevation were set out; there are
currently twelve per elevation at all but the high elevation where
fifteen remain.
Low, hardwood - southwest of W6 weir, west of tower platform -
elevation 525 m
Mid, hardwood - west of Throughfall collector sites - elevation 585 m
Upper, hardwood - west of tower site and seep - elevation 725 m
High, hardwood - west of rain gauge 9 - elevation 830 m
Throughfall Sites:
These sites are located along the W6 trail except for the lower site
which is located within the "wedge" area east of W5: ten
collections per elevation (two 0.097 m2 collectors randomly situated
along five transects):
Low, hardwood - elevation 520 m
Mid, hardwood - elevation 580 m
Upper, hardwood - elevation 730 m
High, spruce/fir - elevation 790 m
DATA DESCRIPTION
Fine litterfall (foliage, buds, seeds, fruits, bark and twigs/branches
<2 cm diameter) is collected three times each year: soon after
snowmelt (May), late summer before leaf fall (September), and late
autumn after leaf fall (November). Note: Coarse litterfall is
collected from cleared plots at a subset of the sites (see Hubbard
Brook Coarse Litterfall Data). Spring and Summer collections are dried
and weighed, Fall collections are sorted by species and tissue. Tree
leaves are counted for each trap and seeds (except birch) are counted.
A subsample of leaves of each species is taken for measurement of area
per leaf. Leaf area index is estimated for each trap as the product of
average area per leaf and leaf number. The whole sample is dried and
weighed. All data except LAI are expressed per trap (0.097 m2) in the
data set. Values found under species headings are leaf counts.
SAMPLING DESIGN
The location of the 16 plots (four each in W1, W5, Bear Brook (west of
W6), and Throughfall collection sites) have been chosen to stratify
the sampling by elevation zones. These sites are co-located with
sampling for soil CO2 flux, fine root biomass, throughfall, soil
solutions, microbial biomass and microarthropods. Within sites,
collectors are positioned randomly.
