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University of Minnesota
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Methods for Experiment 271 -

Experiment Design

The FAB 1 High density diversity experiment consists of 8,960 trees of 12 native species. Four of these species are gymnosperms: eastern red cedar (Juniperus virginiana) and white (Pinus strobus), red (P. resinosa), and jack (P. banksiana) pine. The eight angiosperm species include red (Quercus rubra), pin (Q. ellipsoidalis), white (Q. alba), and bur (Q. macrocarpa) oak; red maple (Acer rubrum) and box elder (A. negundo); paper birch (Betula papyrifera); and basswood (Tilia americana).

Each of FABs three blocks (spaced 4.5 m apart) consists of either 46 or 47 square plots, each 3.5 m on the edge; plots are planted with one, two, five, or 12 species, with two-species plots additionally designed to tease apart functional and phylogenetic diversity. Each plot contains 64 trees, planted at 0.5 m intervals. Within a block, all trees are planted on a contiguous grid, without extra space in between plots.

Each block contains 12 monocultural plots and 28 bicultural (two-species) plots; each of these plot types (or compositions) is therefore replicated three times across the experiment. Each block also contains either three or four random-draw five-species poly-cultures, the compositions of which are not replicated in the experiment, giving replication of the five-species level of richness but not of each five-species polyculture's composition. Each block also contains three or four 12-species polycultures, such that this composition is replicated 10 times across the experiment. Half of the 28 bicultural plot compositions were chosen by random draw. The other remaining bicultures were chosen using a stratified random approach designed to provide plots both low and high in PD and FD.

Planting and establishment

The experimental site was burned, then mulched with wood chips (from non-native western red cedar [Thuja plicata]) to prevent regrowth of herbaceous species. The experiment was planted over one week in late May 2013 with regionally sourced bare root seed-lings of unknown genetic relatedness that ranged from 1 to 2 years in age. Prior to planting, seedling roots were coated with commercial ectomycorrhizal and endomycorrhizal inoculum including species known to associate with all genera included in the experiment (Bio Organics, New Hope, PA). We used sprinkler irrigation to water newly planted seedlings ad libitum through June and July 2013. We replanted seedlings as needed in May/June 2014 to 2015; mortality was roughly 7 to 10 percent following replanting.

aepe271 - Sapling Census

FAB Sapling Census Protocol

FAB Sapling Census Protocol


Use a folding ruler to measure the height of each tree.
Measure from the base of the soil to the tip of the sapling?s leading stem.
Measure from the soil surface, not from the mulch surface. Insert ruler into mulch if necessary.
The leader is the tallest live, vegetative stem.
Measure to the base of the leader?s apical bud. Do not include bud scales or, for conifers, new needles.
If there are multiple stems, pick the tallest living stem.
Make sure that the ruler follows the contours of the stem, especially for curved stems.
Report height in centimeters to the nearest 0.5 cm. (All heights should end in ?.0? or ?.5?)

Use calipers to measure the diameter of the sapling at 5.0 cm from the soil surface.
Before measuring and repeatedly throughout the day, check the caliper to make sure that it reads 0.0 cm when closed.
If the tree has already been measured, find the orange or pink paint pen mark indicating where it was measured previously. Use calipers to record the measurement at that point.
If the tree has not been measured previously or a paint pen mark is not apparent, measure 5.0 cm from the soil surface (see Height) using a ruler and mark the tree with a ring there. Measure from that point.
If the stem forks before 5 cm or is otherwise not amenable to measurement at 5 cm, mark and measure at a different height and note this on the data sheet.
If the stem forks and both resultant stems seem vigorous, measure below the fork.
Report Diameter in centimeters to the nearest 0.5 mm. (All diameters should end in ?.0? or ?.5?)"

aere271 - Initial soil pH

Initial soil pH -instrumentation

Orion 420A pH meter

Intital Soil pH protocol

Soils were collected at depths of 0-15cm, 15-30cm, and 30-60cm, sieved through a 2mm sieve, air dried, and 10g soil (plus 20ml DI water) weighed for pH analysis.

afee271 - Soil bulk density

Soil bulk density protocol

Soil cores were taken from 0-15cm, 15-30cm, and 30-60cm in randomly chosen FAB1 plots. The soil samples were dried and weighed. Dry weights were divided by the volume of the soil core (diameter=5cm).