EXPERIMENTAL DESIGN AND METHODS: Plots were setup in June 1981 with annual fertilization treatments of 10 g/m2 Nitrogen (as NH4NO3) and 5 g/m2 Phosphorous (as triple superphosphate) were applied. Greenhouses and shade houses were annually set up in late May or early June and removed in the end of August or early September. Greenhouses and shade houses were discontinued in 1989. There are 4 replicate blocks, each containing 1 replicate of each of the following treatments.
Control (CT)
Fertilized (NP)
Greenhouse (GH)
Greenhouse fertilized (GHNP)
Shade (SH)

Harvests occurred on the following dates:

Date Site Treatment
-------------------- ------------------------------- ----------------------------------
01-Jun-1982 1981 Toolik Tussock Control
31-Jul-1982 1981 Toolik Tussock Control
01-Sep-1982 1981 Toolik Tussock Control
21-May-1983 1981 Toolik Tussock Control
Greenhouse
Greenhouse Nitrogen Phosphorus
Nitrogen Phosphorus
Shade
14-Jun-1983 1981 Toolik Tussock Control
Nitrogen Phosphorus
03-Jul-1983 1981 Toolik Tussock Control
Nitrogen Phosphorus
30-Jul-1983 1981 Toolik Tussock Control
Greenhouse
Greenhouse Nitrogen Phosphorus
Nitrogen Phosphorus
Shade
23-Aug-1983 1981 Toolik Tussock Control
Nitrogen Phosphorus
26-Jul-1984 1981 Toolik Tussock Control
Nitrogen Phosphorus
21-Jul-1989 1981 Toolik Tussock Control
Greenhouse
Greenhouse Nitrogen Phosphorus
Nitrogen Phosphorus
Shade
31-Jul-1995 1981 Toolik Tussock Control
Nitrogen Phosphorus
30-Jul-2000 1981 Toolik Tussock Control
Nitrogen Phosphorus

SAMPLING TECHNIQUES: Biomass quadrats, size 20x20 cm, were taken from Toolik tussock site. Five quadrats were taken from each of four blocks. All aboveground biomass plus belowground stems and rhizomes were clipped in 20x20 cm quadrats. Normally, 4 or 5 quadrats were randomly located along line transects in each of four replicate blocks for each treatment. Aboveground biomass is considered "within" the quadrat if it is associated with a meristem that is within the quadrat. Quadrats were sorted within 24 hours into species and then into tissue type. Depending on the harvest, tissue types can be broad categories, i.e. above and below, or more detailed, i.e. inflorescences, new growth, old growth, etc.

They were then dried at 50-70 degrees Celsius in a drying oven. After several days in the oven samples were weighed to nearest milligram. Finally the samples from all quadrats from a transect were combined according to tissue type. For some harvest samples were returned to Marine Biological Lab, Woods Hole, MA for nutrient analysis. Details are given in Shaver and Chapin (Ecological Monographs, 61(1), 1991, pg. 1.)

Leaf area was measured in 1995 and 2000 harvest with a LiCor LI-3000A area meter. Leaf areas for graminoids, deciduous, and forbs were measured immediately after plucking and before drying. Leaf areas for Evergreen species (except Ledum) were measured after drying for 2-4 days. Leaf areas for Ledum were measured after final dry weights were done. Cassiope leaf areas were measured on the unseparated leaves and stems.

DATA ENTRY:

Data were entered into spreadsheets as weights in grams, to the nearest milligram. Categories are same as on data sheets. Missing values are represented with blank spaces.

Tissue categories codes: v0 is an immature graminoid tiller that does not have any green tip. v1 is an immature graminoid tiller that has a green tip. CYS is graminoid current year senescence.

Biomass categories:

New Above: includes blade, sheath, v0, v1, CYS blade, CYS sheath, inflorescence, inflorescence bud, new leaves, new stems, and new above (for Forbs and mosses).

Old Above: includes old leaves and old stems.

Below: includes below stems, rhizome and below (for forbs).

(10) NOTES: For 1983-84 harvests in the original file, Quadrats Q1 - Q5=Block 1, Q6 - Q10=B2, Q11 - Q15=B3, Q16 - Q20=B4. For example, Q6 from 1983 is the same as B2Q1 in 1989. In this file the quadrats were renamed to B1Q1 style where the number following the B is block number and the number following Q is quadrat number.

Cassiope was not separated into leaves and stems. Weights for Cassiope were recorded as leaf weights.

Missing values are represented with blank spaces.