Tree Mapping Protocol

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This page is outdated and is archived 2014/11/07 These methods WERE NOT used in the 2012-2013 census

Mapping the 25x25 meter grid with PVC pipe

This is done by ‘expert’-level field workers


  • The 25x25 meter grid must be sectioned into 25 sections measuring 5x5 meters, think of it like a chess board.
  • Begin in the south west corner of the 25x25 meter grid and the first 4 points you will mark will be between the south west point and the North West point. In essence you are marking the west side of the 25x25 meter grid first.
  • Before a measurement is made use the provided string to draw the straightest line possible between these two corner points (the western edge) of the 25x25 meter square for reference.
  • To lay out the points use the DBH poles and pre measured 5 meter wire and the line levels. Adjust the wire as close to the ground as you can without making contact with any debris.
  • Once this is done use the line levels to adjust the wire to a near level position.
  • When you believe the line is level, have you DBH pole as close to perpendicular to the horizon as possible using the pole level, mark your point.
  • When you have your point take a section of PVC and drive it into the ground as straight as possible until only a small ring (half an inch) of PVC shows above ground.
  • Repeat this process around the perimeter of the square.
  • When the perimeter is laid out continue the process of laying a guide string out using the points you measured along the perimeter and measuring along these lines with the 5 meter string and poles to mark all the corners in the 5x5 grid.


Mapping protocol for the 5x5 m subplots within the 25m x 25m plot

  • Subplot numbering
    • Subplots are numbered by numbers (rows) and columns (letters)
    • The Southwest most 5m x 5m subplot is subplot 1,A
    • Number increase sequentially by rows and columns from SW – NE
    • The NE most subplot is plot 5,E; NW 5,A; SE 1,E
  • Start mapping at subplot 1,A and proceed north to 5,A. Then go left to 5,B and proceed south to 1,B. Continue this zig-zag pattern until all plots are mapped.

Laying out the 1x1 Meter Grid within the 5x5 Meter Grid

An expert-level field worker will assign you a 5m x 5m plot for tree mapping. They will:

    • Write on your ‘tree map sheet’ the corner points specific to the 25m x 25m plot you are mapping within.
    • Indicate with an ‘X’ the subplot that you are mapping in.
    • Write on your ‘tree data sheet’ the specific 25m x 25m plot and subplot that you are mapping within.
    • Use pin flags to mark out your 5m x 5m box and specify the SW corner where you will start mapping.


Once you have been assigned a 5x5 meter square

For the following procedures you will have a group of three people to work with. One person should be designated as the data recorder and director of the group with the instructions. The person recording the data should remain the same to ensure consistence. If there are any questions no matter how trivial ask one of the instructors.

1. Use the provided white rope and 6in nails to draw a line between the corner PVC markers. Attach the string to the end of a nail and drop it into the pvc pipe. Then stretch the rope to the next corner pipe and do the same. Do this 4 times until the perimeter of the 5x5 meter grid is mapped out.

2. When you have the perimeter drawn out the next step is to form a 1x1 meter grid within the 5x5 meter grid.

3. To do this simply use a meter tape to measure along one of the perimeter sides (to the nearest cm) you just referenced with string. When this is done take the measurement you achieved and divide it by 5. This will be the length of the intervals between the new ropes you will lay down.

4. Begin at the PVC marker and mark every point along that side of the square with the determined length. Mark these points with a nail, even if they are larger or smaller that 1 meter.

5. Measure the other sides in the same fashion and draw the rope from one side to the other matching the points marked with nails. Do this until you have an entire 1x1 meter grid drawn out.

6. When there is a tree or some other debris in the way of your string simply lay it out as accurately as possible. Bend the string around the tree, eyeball the string as straight as possible.


Mapping Trees in the 5x5 Meter Grid

1. Recording tree data on the MAIN DATA SHEET:

a. Starting in the SW 1m x 1m quadrat of your 5m x 5m subplot, identify the first tree within the quadrat.

b. Measure the DBH of the tree using the DBH tape at 1.37m above ground by placing the DBH stick parallel to the tree stem. Refer to Figure 1 for where to measure the DBH if trees are leaning, on a slope, or are irregular.

  • If a tree is below DBH in height and less than 1 cm in diameter it will not be recorded.
  • If a tree is below DBH in height and greater than 1cm in diameter, it should be tagged, mapped and inventoried as described below with the special code I on the MAIN DATA SHEET.

c. Tag the tree.

  • Place the tag several inches above or below where DBH is measured.
  • If a tree has multiple stems below DBH and is obviously connected as the same tree above or below ground, then that tree will receive a single tag, placed on the largest of the multiple stems.
  • Stems greater than 10cm DBH will be tagged using a nail, leaving about 1.5” of the nail outside the bark.
  • Stems less than 10cm DBH will be tagged using the metal wire with sufficient extra wire to allow for growth: 60cm wire for stems < 6cm DBH, 1m wire for stems < 10cm DBH.


2. Mapping tree location on the TREE MAP SHEET: a. Within the 1m x 1m plot place a dot ● on the tree map sheet that corresponds to the center of the stem at the ground.

b. There should only be one ● on the map for each tree tag placed on a tree.

c. Draw a circle around the ● that corresponds roughly to the diameter of the tree.

d. To account for trees that lean, or trees with multiple stems, place a + at approximately the location where the tree DBH is measured. Draw a faint line from your dot to the + to indicate they are from the same tree.

i. For single stem trees that do not lean, the + will be on top of the ●, this is OK. ii. For single stem trees that lean, place the + at approximately the location where DBH is measured relative to the location of the ●. iii. Mark in the special codes column the code L, for a leaning tree, and also record the height perpendicular to the horizon where DBH is measured. This distance will always be smaller than 1.37 meters. iv. For trees with multiple stems, place the + at approximately the location of where the DBH is measured on each stem. On your TREE MAP SHEET give these multiple stems a number ie a (1) next to the first +, a (2) next to another, and so on. v. When recording multiple stem trees on the TREE MAP SHEET do not record the DBH here. You must turn to the MULTIPLE STEMS SHEET and record the tree tag of the tree with multiple stems here as well as the MAIN DATA SHEET. vi. When recording this tree on the MULTIPLE STEMS SHEET record the multiple DBH’s here. in the DBH columns mark which stem it is and its DBH, ie (1)12.2cm, in the next column (2) 8.9cm and so on.

e. Clearly mark the tag number near the tree ●, if necessary draw an arrow between the number and the corresponding tree dot.

f. If one of the 1 meter lines intersects a tree simply draw the circle accordingly.


3. Filling out the MAIN DATA SHEET: a. On the MAIN DATA SHEET record the tag number and DBH of the stem where the tag was placed.

b. Refer to the SPECIAL CODES SHEET and add any necessary special codes.

c. For multiple stems: i. Indicate the special code M on the MAIN DATA SHEET, ii. On the MULTIPLE STEM SHEET indicate the tag number for the tree and write in the other DBH measurements.

d. If identifying species, follow the SPECIES ID GUIDE and indicate the species code on the MAIN DATA SHEET. i. If you are unsure of the species, leave it blank.

4. Continue mapping, tagging and inventorying the remaining trees in the quadrat, then continue mapping trees within the 5m x 5m subplot following Figure 2.

[[File: Image mapping protocol.png]]

[[File: Image mapping protocol.png]]