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Soil Core Installation

This process is started out by initiating a soil pit near the Biotron at the University of Michigan Biological Station. Kayla Mathes has selected an area within the forest just west of the path leading to the Biotron for soil removal.

Select an approximately 6 foot by 6 foot area as your soil pit. Using a shovel, remove all leaf litter, and the top 3 inches or so (all organic layer) from this patch of soil.

Using the shovel, start to fill the empty bucket with soil, until filled to the top. You may need to saw large roots with the wood saw as you dig into this pit, and also will want to hand remove most large clumps of roots and woody debris as you fill the bucket. Try to get a homogenous sample of the soil, and dig no deeper than 30 cm into the soil throughout the soil pit (the depth of a given soil core).

Take the bucket and the large tarp out onto the path to begin the sieving process. Set up a chair if desired.

Stack the two soil sieves on top of each other. The best way to do this is to have both sieves positioned with the metal side up. This provides an area for the soil to accumulate within each of the two layers provided by the sieves, so that it can more easily fall through the cracks.

Dump about half of the bucket onto the sieve, and with your hands start to spread out the soil and allow it to fall through the first sieve. Repeat until you have sieved through the entire first bucket.

Remove the top sieve and sieve the soil sitting on the lower sieve until it all falls through to the tarp.

Shake off both sieves, and check the top layer of the soil pile you have created for a layer of fine roots- they often settle at the top of the soil pile.

Using the milk carton scoops, fill the cores, tapping them down on the ground to make sure they are fully packed. Fill them all the way to the top, fully packed, so that you have extra soil to work with in case they spill on your way out to the field.

Wrap each soil core with one layer of wax paper, tape it with masking tape, and place it back within its soil core bag.

Repeat process until all soil cores are filled. It takes usually about 10-12 buckets.

Stack cores so that they are all standing up straight in a vehicle, and so they are braced against each other and the walls of the vehicle so they will not slide around.

Drive out to the starting positions for A, B, C and D. For each subplot, there will be 4 cores, located at the North, South, East and West sides of the plots. The North point of the plot is indicated by a blue pole, and all other points are indicated by orange poles (some of these have faded over time). Each pole also has a leaf litter trap next to it. There should be two blue flags placed in the ground near this leaf litter trap and pole. The one nearer to the leaf litter trap marks the position of the soil collar. The other one, which should be found a meter away from the soil collar in the opposite direction of the leaf litter trap, marks the position of the soil core hole. If these flags are missing, you can usually use the typical spacing described here as a way to find them. Replace flags as needed.

If the hole is found too close to another older hole, or cannot be found at all, a new hole can be dug using the steel pipe. Using a sledgehammer, drive the steel pipe into the ground until it is as deep as the bottom line on the red tape.

If the hole is found and is in a good position, use the sledgehammer to drive the steel pipe into the hole, to allow for the dirt to be removed that may have accumulated at the bottom of the hole. If necessary, use your hand to pull any loose dirt that remains at the bottom of the hole.

Place the core into the hole, and using the spare dirt from the steel pipe, fill in the gaps between the core and the walls of the hole.

Repeat for all cores across FoRTE.

Vegetation Plot Sampling

1.Within each subplot (i.e., A01E), there are 4 vegplots: Northwest, Northeast, Southeast, and Southwest. These are all found approximately halfway between the cardinal direction poles that make up the name of each vegplot (i.e. the NW vegplot is about halfway between the orange western pole and the blue northern pole), positioned slightly closer to the center pole. They are marked out with thin PVC pipes marking each corner, and each PVC pipe has a red flag placed within it. The plots are 2 m x 2 m squares.

2. For the past 3 summers (2020, 2021, 2022), we have only sampled the Northwest and Southeast corners of every vegplot. This means we are sampling 2 of the 4 1 m segments that make up a given vegplot. To sample a spot, take the collapsable 1 m x 1 m PVC grid and place it on top of the corner under study. The easiest way to do this is to place it on top of the corner pipe corresponding with the corner you are studying, and then slide it around, using the other PVC pipes as reference, until it is lined up appropriately to capture that corner. You may need to use the collapsable side of the grid to adjust it to fit around small trees, branches, etc.

3. To sample, examine every seedling that belongs to a species that has the potential to become a tree that is rooted within the grid that you have placed down. For some species, especially the ACPE in A, it can be difficult to find where it is rooted, so you must be persistent. For any plants that are at least as high as breast height and measure 1 cm or more diameter at breast height, they are not to be measured. Anything smaller than this is censused.

4. To measure a seedling’s base diameter, take it’s base diameter with the caliper, at the location right above where it is rooted in the soil. These sizes can be placed into bins: for all with base diameter from 0 - 0.39 cm, it can fall within that bin. Base diameter any higher should be measured to the nearest 0.1 cm.

5. For a seedling’s height, take a standard ruler and measure to the height of the base of the highest leaf. This means that where the stem of the highest leaf meets the central stem is where you measure to. For some species, especially FAGR and ACPE, you may have to stretch the plant out as it will be viney/bent over. For most small seedlings, though, a measurement can just be taken from the base of the plant without touching it. For plants where leaves have either fallen off or it isn’t distinctly leafy (i.e. AMEL), measure to the highest point of the woody stem. Measure to the nearest millimeter. Remember, the ruler has 0.5 mm of space at its bottom that needs to be added back to all measurements, but the code designed by previous graduate students often accounts for this. Once this step is complete, use the paint pen to make a small mark on the stem to keep track of which plants have been measured as you work your way around the grid.

6. The only species we have ever seen are, from approximately most common to least common: ACRU (Red maple), ACPE (Striped maple), ACSA (Sugar maple), FAGR (American beech), AMEL (Serviceberry), QURU (Northern red oak), PIST (White pine), POGR (Bigtooth aspen), POTR (Quaking aspen), FRPE/FRNI (Ash), ABBA (Balsam fir). Old codes you might see are VBAC (should be VIAC, maple viburnum, which is an herbaceous species), FRAM (another type of ash, it's debatable what the couple of ash that we see are, yellow ash, green ash or black ash). VBAC/ MAPLE VIBURNUM SHOULD NOT BE COUNTED. See the “Vegplot Species Key” for some help identifying these species (link here). Generally speaking, the species are easy to tell apart, but watching out for VBAC and distinguishing between very young ACRU and ACPE are the things that require the most training.

Subcanopy Survey Protocol

1. There are about 279 trees censused in the subcanopy study. These trees can be found clustered around the 4 vegplots found in the subplots (the 1 meter by 1 meter squares surrounded by PVC pipes with red flags placed within them): the Northeast, Southeast, Southwest and Northwest vegplots. They are often even found inside the plots. They are always tagged with circular tags, usually hung from the tree with pink or white colored wire, and are tagged typically with white flagging on one of its branches (sometimes, you will see small trees that have orange flagging that are of similar size, and these are Lisa’s trees that are not censused).

2. Some trees will have no flagging, however, but you will get good at guessing which trees might be the ones under study.

3. Like with the dendroband reading, the best process is to have the recorder find the trees and to have the reader follow them and read those trees.

4. Use quality calipers, usually made not just of plastic, to measure these trees (the calipers used in the example below are not of great quality). You must find the spot on the tree where the previous recorder recorded the tree, always marked with an orange paint pen line and usually near breast height (1.37 meters above the ground). Make a new mark over this line if it is fading at all after measuring.

5. It is important to look straight on at the caliper, and to make sure that the two sliding pieces are lined up properly, and one isn’t distorted. This may require adjusting your position in relation to the tree.

6. Take notes on any trees missing tags, or trees that have died.

Canopy Dendrobands

1. There are about 667 trees throughout A, B, C and D that have dendrobands that must be read every season. Some of these trees have top and bottom bands that need to be read. Some of these extra bands were installed in order to study whether there was any kind of swelling going on near the girdle. Some other extra bands have been installed in 2022 for trees where the stickers are becoming harder to read. These bands almost always were installed below the original bands, and we hope that the original band is still readable for long enough for the trees to grow into their new bands (new bands were installed before June 24th, 2022 and after May 23rd, 2022).

2. Bands are arranged on trees clockwise from plot center, starting from the north pole in each FoRTE subplot. The easiest way to get it all done is to have one recorder search for each tree individually, and the reader read those trees as the recorder finds them. Start with a tree close to north, and work your way clockwise through the plot. Some trees may be surprisingly close to plot center or far away from the plot center, so use the data on the species and size of the tree as a guide to find it. Say that the first number of your plot is 607, and the last number is 712- 607 will likely be just to the right of the north pole, and 712 will likely be just to the left of it (the end of the clockwise circle).

3. Read each dendroband with care, and take note of any that are unreadable. Do not give up easily on reading the dendrobands, because often, as you will see in the examples below, there are “shadows” of lines that can be used to judge how much the tree has grown. Certainly take notes if you feel that the stickers, either the one closer to the tree or further from the tree, need replacing. For trees that certainly need their sticker closer to the tree replaced, the whole band must be replaced. For trees that certainly need their sticker further from the tree replaced, often a new sticker can simply be installed on top of the old one.

4. To read a dendroband, find where the 0 line of the overlaid sticker lands in relation to the sticker on top of it. This will give you the first whole number and the first decimal number of what will eventually be a 1 whole number, 2 decimal number that you create (i.e, 2.43). To find the second decimal number, find the overlaid sticker line that lines up best with a line on the sticker closer to the tree. Use the pictures and associated notes below to guide you through this process. Sometimes, it can be useful to carry a pencil out and draw on top of the shadows of lines, and give you a better sense of where things line up.

5.Take note of any trees that have lost their dendroband, have had it mangled by another tree, or are so dead that the band is now loose and expanded on the exterior of the tree because of the loss of bark. Sometimes, if a tree has overgrown its band, you can use a caliper to measure the distance from the end of the band to where it would have landed if it still had room on the sticker, and this can be used to still calculate its full growth. Note this when recording as “ + 1.625 cm” or whatever it may be.

Fern Count

1. Use the 1x1m PVC pipe quadrant, and place it so that you can measure the NW and SE quadrants of the 2x2m vegetation plots located within each subplot. There are four vegetation plots per subplot, and two quadrants to measure within each vegetation plot.

2. Using an orange paint pen to keep track, begin counting all of the ferns within the 1x1m square. Once they have been counted write up the tally on the data sheet, and move to the next quadrant.