Canadian Airborne Biodiversity Observatory's Forest Inventory Field Survey Protocol

Systematically establish plots to span the range of conditions across the imaged area. Specifically, we aim to:

1. Maximize the number of unique tree species assemblages
2. Cover the range of topographic conditions (e.g., elevation, slope, and aspect)

In the field,

• Permanently mark plot centers with rebar¹ topped with orange safety cap (Fig. 1) and label cap² as follows: CABO - Plot ID - Initials of Surveyors - Date Established

• There is no need to physically delineate the perimeters of the plots - the Postex System that is used to position trees in relation to the plot center is used to determine the plot boundaries. When an individual tree is beyond the slope corrected radius of a plot the system will beep and return a warning message that the Tree is outside the plot . The visible strings (~16 m in length) used to create sampling sections will provide a rough indication of the plot's boundary (detailed in Step 6) and surveyors should sample all individual trees until the Postex System returns the warning message (detailed in Step 7).

In Fulcrum ,

• Create a plot record in Fulcrum by selecting + Record within the Plots app (Fig. 2a,b).
• TAP TO SELECT PROJECT ¹, select the appropriate Site ², assign a Field Plot ID ³, and list the names of the surveyors who the plot was First Established By (Fig. 2c) .
• UPDATE LOCATION WITH GPS ⁴- Latitude (degrees), Longitude (degrees), Horizontal Accuracy (m), and Altitude (m) fields will automatically be filled in when Update Location with GPS is selected (Fig. 2d).
• Assign the Plot Shape as circular and Plot Diameter (m) as 30 ⁵ (Fig. 2e).
• Optional - Add details about species assemblage to Plot Remarks ⁶ and photos to Plot Photos (Fig. 2e) .

For each plot, quantify the slope and orientation in the field¹.

• Measure the slope angle and compass bearing with the LaserGeo's ANGLE and COMPASS ² functions, respectively, along two 7.5 m vectors in the direction from high to low elevation, where: i) the first vector is parallel to the steepest slope and

                ii) the second vector is oriented in any direction as long as it is not parallel to the first 
  
                    (Fig. 3a). 
  

• Enter the slope angle and compass bearing measurements to Slope 1 (°) , Bearing 1 (°) , Slope 2 (°) , and Bearing 2 (°) fields within the plot's record in Fulcrum (Fig. 3b) .

  

In Fulcrum :

• SAVE ¹ the plot record in Fulcrum (Fig. 4a). This will return you to the Plots app.

• Sync² Fulcrum to upload new plot record online by selecting the icon of two circular arrows. This icon will spin when synchronizing is in progress (Fig. 4b).

  

Prior surveying a plot, create the plot's vegetation survey record in Fulcrum.

• Create a record for the plot's vegetation survey in Fulcrum by selecting + Record in the Vegetation Survey: Large Trees app (Fig. 5a,b).
• TAP TO SELECT PROJECT , select the appropriate Site and the corresponding Field Plot ID , answer No to Trees Measured in a Subplot? ¹, and list the names of who the plot will be Surveyed By (Fig. 5c) .
• For Tree Positioning Method select X-Y POSITION FROM PLOT CENTER and for Tree Size Measurements select DBH, Height, Crown class, and Crown diameter (Fig. 5d).
• Select Tree Taxa Present followed by + Record (Fig. 5d,e).
• If needed, you can apply filters but regardless, select VASCAN Taxon ² and choose a species present in the plot from the drop-down list (Fig. 5f).
• Once species is selected, select SAVE (Fig. 5g). The species you just entered should now appear on the Tree Taxa Present page (Fig. 5h).
• Select + Record if additional species are present and repeat the previous two steps (Fig. 5h,f,g).
• Repeat this process until all species present in the plot are listed under Tree Taxa Present , then return to the plot's Vegetation Survey record by selecting the arrow (←)(Fig. 5i)

  

Prior to surveying a plot, set-up the Postex system.

• Set-up the Postex system, center the tripod over the plot center, and create a new plot in the DP II handheld device (Fig. 6). Please see the Postex System User Guide for instructions detailing how to set-up and use the system.

  

Prior to surveying a plot, divide the plot into sampling sections.

• Given the large size of sampling plots (~706 m²), use visible strings ~16 m in length attached to ground spikes (Fig. 7a) to divide the plot into sampling sections - attach strings to plot center and extending to the plot edge.

• The number of sampling sections is dependent on tree density and is up to the surveyors discretion¹ (i.e., more dense stands, more sampling sections to ensure all individuals are sampled and only sampled once).

• A minimum of three strings are needed - start by delineating two sampling sections and move the center string to delineate the next sampling section once the first two sections are surveyed and repeat until entire plot is surveyed (Fig. 7b).

  

Survey all individual trees within each plot¹ that meet the following selection criteria:

1. All individuals with crowns in the general canopy-level (i.e., all individuals with a crown class of Dominant, Co-dominant, or Intermediate; see Step 7.5 for crown class definitions)
2. Individuals with crowns below the general canopy-level (i.e., individuals with a crown class of Suppressed) that have a DBH ≥ 9 cm.
3. Standing dead trees that extend into the upper canopy-level (i.e., same height as the dominant crown class).

For every individual that meets the selection criteria, identify it to species (see Step 7.2), measure DBH and position it (see Step 7.3), measure height (see Step 7.4), assign a crown class (see Step 7.5), and measure crown area and orientation (see Step 7.6).

For each individual, create a record in Fulcrum.

• Create a record for an individual by selecting Surveyed Trees within the plot's Vegetation Survey record and then + Record (Fig. 8a,b) .

  

Identify the individual to species.

• Identify individuals to species and enter taxonomic identity within Tree Taxon ¹ field in the individual's Surveyed Trees record in Fulcrum (Fig. 9) .

  

Use Postex system to measure DBH and position individual (see Step 6 in Postex Sysem User Guide),

• Use the LaserGeo's ANGLE function to measure the angle between the individual at breast height (~1.3 m) and the center of the Postex tripod.
• Select Measure in the DP II handheld device and enter the ANGLE between the individual and the Postex tripod as measured with the LaserGeo.
• Spec will be highlighted in the DP II handheld device, enter a numeric species code (optional) and/or press Enter.
• D will be highlighted in the DP II handheld device, position the SmartScale caliper at breast height^1,2,3 with the mounted DP DME oriented toward the plot center, and press Enter (Fig. 10a). The DBH will be measured and displayed (Fig. 10b); enter the value to DBH (cm) field in the individual's Surveyed Trees record in Fulcrum (Fig. 10c).
• Press enter in the DP II handheld device to position the individual and display the X-Y coordinates (Fig. 10b). Record the X-Y positions in the X Position (m) and the Y Position (m) fields in the individual's Surveyed Trees record in Fulcrum (Fig. 10d) .
• If you are unable to obtain a position using the Postex system⁴, use the LaserGeo's DME and COMPASS functions to measure the distance between the individual's trunk at breast height to the plot center and the compass bearing, respectively. Take distance and compass bearing measurements directly against individual's trunk at breast height (i.e., from the same position that the Postex DP DME would). Enter the distance and compass bearing to Distance from center (m) and Compass bearing (°) fields in the individual's Surveyed Trees record in Fulcrum (Fig. 10e) .

Use LaserGeo to measure individual's height.

• To account for uneven ground, use the LaserGeo's HEIGHT 3P function that quantifies the height by measuring: 1) Distance to the individual's trunk at eye-level,

                2) Angle to the base of the trunk, and
  
                3) Angle to the tip of the individual's crown<sup>1,2,3</sup>(Fig 11a),
  

• Enter the height to Height (m) field in the individual's Surveyed Trees record in Fulcrum (Fig 11b).

• Optional - Enter height into DP II handheld device ( H will be highlighted after measuring the individual's position) and/or press Enter. The device will beep and advance to the next individual, bringing you back to the ANGLE step.

  

Assign individual to a crown class, a categorical variable that describes the vertical position and dominance of individual crowns

• Determine crown class of an individual, by comparing it to trees in its immediate proximity¹(Table 1, Fig. 12a).
• Enter the crown class to Crown Class field in the individual's Surveyed Trees record in Fulcrum (Fig 12b).

A	B
Dominant	Individuals with crowns extending above those of surrounding trees. Crowns are well developed and experience full sun from above and partially from the sides.
Co-dominant	Individuals with crowns at the general level of surrounding trees. Crowns are not distinct from surrounding trees, receiving full sun from above but not the sides.
Intermediate	Individuals with crowns below those of surrounding trees, where individuals are approx. 2/3 the height of surrounding trees. Crowns are not well-developed and receive little-to-no direct light.
Suppressed	Individuals with crowns below those of surrounding trees, where indivduals are less than 1/2 the height of surrounding trees. Canopies are not well developed and receive little-to-no direct light.

Table 1. Crown class definitions as modified from Canada's national forest inventory ground sampling guidelines (NRCan, 2008).

Use LaserGeo to measure crown dimensions and orientation.

• Take the compass bearing and measure the length of the longest crown dimensions using the LaserGeo's DME and COMPASS functions (Fig. 13a) and enter the measurements in Bearing (°) and Canopy distance 1 (m) fields, respectively, in the individual's Surveyed Trees Fulcrum record (Fig. 13c).

• Measure the distance from crown's edge to the individual's trunk using the LaserGeo's DME function, from the crown edge in which the compass bearing was quantified (Fig. 13a) and enter the distance in the Canopy to tree trunk (m) field in the individual's Surveyed Trees Fulcrum record (Fig. 13c).

• If the individual is angled to the extent that the trunk at the DBH is not under the crown (Fig. 13b), then measurements are taken as described above but enter the distance from the crown's edge to the individual's trunk as a negative number in the Canopy to tree trunk (m) field in the individual's Surveyed Trees Fulcrum record (Fig. 13c).

• Measure the length of the crown perpendicular to the longest canopy dimension¹ using the LaserGeo's DME function (Fig. 13a) and enter the length in Canopy distance 2 (m) field in the individual's Surveyed Trees Fulcrum record (Fig. 13b).

• If the individual is a standing dead tree that extends into the upper canopy (i.e., similar height of dominant crown class), there will be no canopy to measure but write Dead in the Measurement Remarks field in the individual's Surveyed Trees Fulcrum record (Fig. 13b).

• Once all measurements are complete, select SAVE ² (Fig. 13b). This will return you to the plot's Vegetation Survey Fulcrum record.

  

Repeat Steps 7.1 to 7.6 until every individual in the plot that meets the sampling criteria has been sampled, surveying individuals sampling section by sampling section (see Step 6). Then save the plot's Fulcrum Vegetation Survey record.

• Select the RECORD STATUS: PENDING VERIFICATION in the plot's Vegetation Survey Fulcrum record and change the status to VERIFIED . The colour of the Record Status bar should change from orange to blue (Fig. 14a).
• SAVE ¹ the plot's Vegetation Survey record in Fulcrum. This will return you to the Vegetation Survey: Large Trees app (Fig. 14b).
• Sync² Fulcrum to upload the plot's vegetation survey record online by selecting the icon of two circular arrows. This icon will spin when synchronizing is in progress (Fig. 14c).

Optional - export data from Postex system to your computer to backup individuals' X-Y positions (see Step 8 in Postex System User Guide).

Return in the Autumn once the deciduous leaves have fallen with Trimble Catalyst (Trimble Catalyst DA1 antenna with Trimble RTX correction service, Trimble Inc.) or alternative high-precision GPS to obtain high-precision coordinates of plot centers (Fig. 15a). See Trimble GPS Protocol for step-wise details regarding how to use Trimble Catalyst.

• Within the Plots app in Fulcrum select the appropriate plot record (Fig. 15b,c).

• The Trimble Catalyst integrates with Fulcrum , select UPDATE LOCATION WITH GPS - Latitude (degrees), Longitude (degrees), Horizontal Accuracy (m), and Altitude (m) fields will automatically be filled in when Update Location with GPS is selected - once GPS connection is established and, ideally, horizontal accuracy is ≤ 0.30 m¹ (Fig. 15d).

• Select the RECORD STATUS: PENDING VERIFICATION in the plot's Fulcrum record and change the status to VERIFIED . The colour of the Record Status bar should change from orange to blue (Fig. 15e).

• SAVE the plot's record in Fulcrum. This will return you to the the Plots app (Fig. 15e).

• Sync² Fulcrum to upload the changes online by selecting the icon of two circular arrows. This icon will spin when synchronizing is in progress (Fig. 15f).

Using the Fulcrum desktop website,

• In CABO's Fulcrum account, select Export Data as indicated by a downward facing arrow (Fig. 16a)

• Select the File Format , in Apps select Plots and Vegetation Survey: Large Trees , in Projects select 2019-MontSaintBruno and 2019-Crofts-PhD-UdeS or alternative, and then select NEXT (Fig. 16b).

• Review Export summary and select CONFIRM to download (Fig. 16c).

Once the forest inventory field survey is complete and data has been checked, change the status of all plots and their associated vegetation survey records to 'Submitted' in Fulcrum.

• Within the Plots app and Vegetation Survey: Large Trees app in Fulcrum select completed and checked plot and their associated vegetation survey records (Fig. 17a,b).
• For each plot and vegetation survey record, select the RECORD STATUS: VERIFIED in the plot's Fulcrum record and change the status to SUBMITTED . The colour of the Record Status bar should change from blue to green (Fig. 17c). Then SAVE the changes in Fulcrum. This will return you to the Plots or Vegetation Survey: Large Trees app (Fig. 17d).
• Once the status of all appropriate plots and their vegetation survey records have been changed, Sync Fulcrum to upload the changes online by selecting the icon of two circular arrows. This icon will spin when synchronizing is in progress (Fig. 17e).