TITLE: Canopy Trees Survey Protocol - Forests of Southern Québec
AUTHORS: Mark Vellend, Sabine St-Jean, Anna Crofts

[DESCRIPTION]
<div class = "text-blocks"><div class = "text-block"><span>Here, we describe the standardized protocol used by the </span><a href="http://www.caboscience.org/" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">Canadian Airborne Biodiversity Observatory</span></a><span> (CABO) to conduct ground-based surveys of canopy trees at forested sites: Parc national du Mont-Mégantic and Mont-Saint-Bruno, Québec. Ground-based canopy tree surveys were conducted in circular sample plots of 15 m radius, with plots distributed across gradients of interest (e.g., species composition, elevation, slope orientation, and logging history), and recorded in the </span><span style = "font-style:italic;">Plots </span><span>app in </span><span style = "font-style:italic;">Fulcrum</span><span>. For each sample plot, precise GPS coordinates of plot centres were taken, as well as slope angle and aspect. Within each sample plot, all trees that met the selection criteria were identified to species and geolocated relative to the plot center using the </span><a href="http://www.haglofsweden.com/index.php/en/products/instruments/calipers/496-dp-postex" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">Postex system</span></a><span> (</span><a href="http://www.haglofsweden.com" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">Haglöf Sweden AB, Långsele, SE</span></a><span>). In addition, height, diameter at breast height (DBH), canopy area, and crown dominance class were estimated for all selected trees. All data were entered into the </span><span style = "font-style:italic;">Vegetation Surveys: Large Trees </span><span>app in </span><span style = "font-style:italic;">Fulcrum. </span><span>In Parc national du Mont-Mégantic, for any tree species that had fewer than 10 individuals assigned as 'Dominant' or 'Co-dominant' (crown dominance classes), across all sample plots, additional individuals found outside sample plots were geolocated and measured to bring the sample size to 10 (data recorded in the </span><span style = "font-style:italic;">Plants</span><span> app in </span><span style = "font-style:italic;">Fulcrum</span><span>). The ground-based canopy tree surveys were conducted in order to be paired with remotely-sensed aerial hyperspectral imagery. </span></div></div>

[STEPS]
?. [Fieldwork Preparation]
Undergo site reconnaissance. Select plot locations as follows:To fulfill the needs of locality-specific research questions, plots should span the gradients of interest (e.g., elevation and logging history), with relatively even coverage at different positions along the gradients. The aim is to maximize statistical power in tests of the basic form: community.property ~ X1 + X2…Xn, in which X1…Xn are plot-level variables that might explain variation in community properties across the gradients of interest.To fulfill CABO-wide needs for the calibration of sensor data, plots (or individual trees) should be sampled to ensure that each tree species is represented by at least 10 individuals considered Dominant or Co-dominant (see “Crown Class” distinctions below).The aim is to have a minimum of 30 plots per site.
?. [Plot Creation and Measurements]
Establish the plot in Fulcrum.
Lots of areas of Parc national du Mont-Mégantic are not covered by cellular reception. Plots can be created in Fulcrum offline but be sure to sync as soon as possible once back in service. Synch by opening the Fulcrum app on your phone and clicking on the 2 circular arrows icon.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
During site reconnaissance (walking between plots), pay attention to: 1) individuals of rare tree species (see attached Species List per Site and step 12), and 2) trees that meet the Leaf Spectra selection criteria. Create and save individuals in the Plant app in Fulcrum.
The following step applies to the larger leaf spectra effort. It represents what the leaf spectra crew asked the veg crew to do prior to their arrival at the Megantic site, in order to save time, as the veg crew has easier access to this site and is familiar with it.
Leaf Spectra Selection Criteria:Leaves exposed to direct sunlight for at least 6 hrs a day.Tree height that allows for leaf collection (target leaves located at ____ m at most).Within 30 mins, ideally 15 mins, from parking spots for the Leaf Spectra van.If possible, sample individuals of the same species across the park (i.e., in both sectors and across the altitudinal gradient).Goal: 10 individual trees per species, for the common species; and 5 individual trees per species, for rare species (see attached Species List).Details to know to assist the Leaf Spectra Crew during leaf collection:The Leaf Spectra van, once settled, won’t move for the rest of the day.Once harvested from the tree, the leaves must remain attached to the branch during transportation to the Leaf Spectra van. If leaf collection occurs before aerial imagery, do not collect leaves inside the plots.Details to know to assist the Leaf Spectra Crew during leaf collection:The Leaf Spectra van, once settled, won’t move for the rest of the day.Once harvested from the tree, the leaves must remain attached to the branch during transportation to the Leaf Spectra van. If leaf collection occurs before aerial imagery, do not collect leaves inside the plots.
?. [Plot Creation and Measurements]
From the Fulcrum main menu, go to the Plots app and then access the Records.
?. [Plot Creation and Measurements]
Create a new record.
?. [Plot Creation and Measurements]
Under Plots → Metadata and Plots → Study Site, respectively select the appropriate Project and Site (see Site Specific Information).
?. [Plot Creation and Measurements]
Under Plots → Location, georeference the plot location approximately by clicking Update Location with GPS on your field cellphone (connected to the Trimble GPS or not) –coordinates will automatically be imported to the Latitude and Longitude fields.
During the growing season, under a closed canopy, GPS precision will be ~ 1 to 5 m, using the Trimble GPS or your field cellphone. This is okay when establishing plots but in the autumn once the leaves have dropped, plots will need to be revisited and location updated to obtain In 2019, the Trimble GPS was used when first establishing the plots, but the field cellphone would have resulted in an equivalent precision (> 1 m), because of the closed canopy. All plots have been or are to be revisited after leaf fall in the autumn or winter 2019-2020 to obtain more precise coordinates (
?. [Plot Creation and Measurements]
Under Plots → Plot, assign the plot a Plot Field ID, and indicate the names of the team members (one or more) creating the plot as well as the date of plot creation.
The default entries are the name of the person logged into Fulcrum and the current date.
?. [Plot Creation and Measurements]
Under Plots → Plot Shape and Size, enter the Plot Shape (Circular), and Plot Diameter (30 m).
The area of standard forest inventory plots is approximately 400m2; this contains too few canopy trees for CABOs goals (i.e., community composition of canopy trees). The Postex system (see below and the Postex System User Guide) has a range of up to 30 to 40 m, however due to the forest density across Mont-Mégantic such range is not possible. A plot diameter of 30 m (15 m Postex range as radius) results in a plot area of approximately 707m2; an area that is more likely to capture canopy tree community properties than standard forest inventory plots and still allows for use of the Postex system.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
From the Fulcrum main menu, go to the Plants app.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Under Plants → Location, precisely georeference the tree location by clicking Update location with GPS on your field cellphone connected to the Trimble GPS –coordinates will automatically be imported to the Latitude and Longitude fields.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Under Plants → Plant First Occurence, indicate the names of the team members (one or more) who first observed the plant as well as the date of the first observation of the plant.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Permanently tag the tree using aluminium tree tags numbered 1-200 –place tag on the far side of tree, so it cannot be seen from the trail. Under Plants → Plant, answer "Yes" to Plant Tagged?, record the tag number next to Tag ID, and answer "aluminium tag" to Tag Type. Add any other relevant info next to Tag Remarks and Plant Remarks.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Create a new record.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Under Plants → Site and Plot, select the appropriate Site (see Site Specific Info) and leave the Plot field blank.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Under Plants → Metadata → Project, select the appropriate project name (see Site Specific Info).
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Under Plants → Taxon, select the name of the plant species from the VASCAN Taxon list.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Under Plants → Taxonomic Identification, indicate the team members (one or more) the tree was Identified By, enter the Date Identified, and indicate the Identification Protocol.
?. [Tree Mapping for Leaf Collection (Megantic Only)]
Save your record.
?. [Rare Trees Survey outside Plots (Megantic Only)]
Survey additional rare trees as needed to ensure that all tree species observed across a given site are represented by at least 10 Dominant or Co-dominant individuals, in order to fulfill CABO-wide needs for the calibration of sensor data mentioned at step 1.
?. [Survey Trees within each Plot]
Survey all trees within each plot that meet the following selection criteria:i) All trees with a crown canopy class of "intermediate", "co-dominant", or "dominant" (see step 9.6 for canopy class designations)ii) Trees in the crown canopy class "suppressed" if DBH ≥ 9 cm.For every tree that meets the selection criteria, identify it to species, measure DBH, position in the plot, height and canopy area, and assign a canopy class (see steps 9.1 to 9.9 for details).
?. [Survey Trees within each Plot]
Under Vegetation Surveys: Large trees → Surveyed trees, select (+) to begin a new entry. Identify individual to species and record it under Taxonomic Identity → Tree Taxon –only the taxa entered in step 7.4 will be available to choose from.
- If needed, add "Identification Remarks" in the appropriate entry box in Fulcrum. This optional field has not been used in the 2019 surveys.- If there is any ambiguity in species, make a note of this in the “Identification Qualifier” entry box in Fulcrum.- All VASCAN recognised tree hybrids are available.
?. [Survey Trees within each Plot]
Measure the tree's DBH, to the nearest millimeter, using the Postex system's SmartScale caliper and DP II handheld device. Record DBH under Vegetation Surveys: Large trees → Surveyed trees → Size Measurement(s) → DBH (cm). If an individual has more than one DBH, use the additional DBH field(s).
?. [Survey Trees within each Plot]
Estimate the tree's position in the plot, using the Postex system. Record the coordinates (the X and Y values, which are relative to the plot center) under Vegetation Surveys: Large trees  → Surveyed trees  → Location –there is no need to record the 3 distance measurements (d1, d2, and d3).
?. [Survey Trees within each Plot]
Estimate the tree's Height, to the nearest 10 cm, using the Height 3P function of the Laser Geo. Record height under Vegetation Surveys: Large trees  → Surveyed trees  → Size Measurement(s) → Height (m).
Height 3P calculates height using: 1) distance to tree (at eye-level), 2) angle to tree base, and 3) angle to tree top. Because of the two angle measurements, this function does not require researcher to be on level ground.To obtain correct measurements, the observer has to be about 10 m away from the tree trunk.
?. [Survey Trees within each Plot]
Assign the tree a Crown Class of "Dominant", "Co-dominant", "Intermediate", or "Suppressed" (as defined below). Record the assigned crown class under Vegetation Surveys: Large trees → Surveyed trees → Size Measurement(s) → Crown Class.  ABC1  Crown class    Code    Description  2  Dominant    D  Trees with crowns that extend above the general level of the trees immediately around the measured trees. They are somewhat taller than the co-dominant trees, and have well-developed crowns, which may be somewhat crowded on the sides, receiving full light from above and partly from the side.3  Co-dominant    C  Trees with crowns forming the general level of the trees immediately around the measured trees. The crown is generally smaller than those of the dominant trees and is usually more crowded on the sides, receiving full light from above and little from the sides.4Intermediate  I  Trees with crowns below, but extending into, the general level of the crown canopy (may include trees, shrubs, or other obstructions) immediately around the measured trees. The crowns are usually small and quite crowded on the sides, receiving little direct light from above but none from the sides.5  Suppressed    S  Trees with crowns entirely below the general level of the crown canopy (may include trees, shrubs or other obstructions) around the measured trees, receiving no direct light either from above or from the sides.
Crown class should be determined based on trees immediately surrounding* the individual measured (not at a per plot level).*The immediate neighbours being all the trees (from all crown classes) whose canopy has a common edge with the canopy of the tree of interest.
ABC1  Crown class    Code    Description  2  Dominant    D  Trees with crowns that extend above the general level of the trees immediately around the measured trees. They are somewhat taller than the co-dominant trees, and have well-developed crowns, which may be somewhat crowded on the sides, receiving full light from above and partly from the side.3  Co-dominant    C  Trees with crowns forming the general level of the trees immediately around the measured trees. The crown is generally smaller than those of the dominant trees and is usually more crowded on the sides, receiving full light from above and little from the sides.4Intermediate  I  Trees with crowns below, but extending into, the general level of the crown canopy (may include trees, shrubs, or other obstructions) immediately around the measured trees. The crowns are usually small and quite crowded on the sides, receiving little direct light from above but none from the sides.5  Suppressed    S  Trees with crowns entirely below the general level of the crown canopy (may include trees, shrubs or other obstructions) around the measured trees, receiving no direct light either from above or from the sides.
?. [Survey Trees within each Plot]
Measure the tree's approximate crown dimensions (Bearing, Canopy distance 1 and 2, Canopy to tree trunk) using the the Compass and DME functions of the Laser Geo.  Later calculations will assume an oval shape for tree crowns, in which case the necessary measurements involve the length and width and the position of the tree bole.    1) Bearing (°): the compass bearing of the longest part of the canopy (compass function).    2) Canopy distance 1 (m): the length of the longest dimension of the canopy (DME function).    3) Canopy to tree trunk (m): the distance to tree trunk of the longest side of the canopy (DME function), measured by the researcher with the Laser Geo standing at the same point than during measurements 1) and 2).    4) Canopy distance 2 (m): the length of the perpendicular side of the canopy (DME function).Record these values under Vegetation Surveys: Large trees → Surveyed trees → Size Measurement(s).
For bearing, there are always two possibilities (e.g., 90 or 270 degrees). We assumed that the position of the two researchers (more upslope or downslope) did not make a difference, as long as the researcher holding the Laser Geo (illustrated by a blue smiley face) does not move from measurements 1) to 3).
?. [Survey Trees within each Plot]
In the case where the tree is leaning or bent to the point that the trunk at breast height is not even underneath the crown, canopy dimension measurements are done as described above, except the distance from the edge to the tree trunk (see measurement 3 below) is entered as a negative number.    1) Bearing (°): the compass bearing of the longest part of the canopy (compass function).    2) Canopy distance 1 (m): the length of the longest dimension of the canopy (DME function).    3) Canopy to tree trunk (m): the distance to tree trunk of the longest side of the canopy (DME function), measured by the researcher with the Laser Geo standing at the same point than during measurements 1) and 2).    4) Canopy distance 2 (m): the length of the perpendicular side of the canopy (DME function).
?. [Rare Trees Survey outside Plots (Megantic Only)]
Identify the tree species represented by
?. [Survey Trees within each Plot]
Save your record.
?. [Creation of the Vegetation Surveys Records]
From the Fulcrum main menu, go to the Vegetation Surveys: Large Trees app and create a new record.
?. [Creation of the Vegetation Surveys Records]
Under Vegetation Surveys: Large Trees → Survey Methodology, answer "X-Y position from plot center" to Tree Positioning Method.For Tree Size Measurements, select the fields "DBH", "Height", "Crown class", and "Crown diameter".
?. [Creation of the Vegetation Surveys Records]
Under Vegetation Surveys: Large Trees → Metadata, select the current Project (see Site Specific Information). Under Vegetation Surveys: Large Trees → Sampling Plot, select the current Plot (as created in step 4), and answer "No" to Trees Measured in a Subplot?
?. [Creation of the Vegetation Surveys Records]
Under Vegetation Surveys: Large Trees → Survey Event, indicate the names of the team members (one or more) doing the vegetation survey as well as the date of the survey.
The default entries are the name of the person logged into Fulcrum and the current date.
?. [Rare Trees Survey outside Plots (Megantic Only)]
Record species identification, DBH, height, and crown dimensions in Plants → Plant Size → Size Measurements.
?. [Rare Trees Survey outside Plots (Megantic Only)]
For these species, find individual trees ≥ 9 cm DBH outside the plots to bring the sample size up to at least 10. If possible, use the trees recorded at step 11. If not, create Plant records for the selected trees by following the directions from step 11.
?. [Rare Trees Survey outside Plots (Megantic Only)]
Save your record.
?. [Plot Creation and Measurements]
Under Plots → Optional Plot Info, take a photo of the plot (Plot Photos) and, if needed, add Plot Remarks (i.e., the reason why the plot was selected, e.g., contains a given rare species).
?. [Creation of the Vegetation Surveys Records]
Under Vegetation Surveys: Large Trees → Survey → Tree Taxa Present, select "Items", then (+), then "Select", and enter the Latin names of all tree species present in the plots. Species are entered one at a time, once one is entered you are returned to the (+) step. This process selects the species you are entering from the built-in complete VASCAN species list, thus avoiding mistakes in the name of species.
If you find additional species when sampling, return to the the Vegetation Surveys: Large Trees → Survey → Tree Taxa Present and enter new species as instructed above. Before continuing with the survey be sure to save the changes if you have internet access.
In some cases, the Latin names in VASCAN and in field guides might differ for a given species. VASCAN is to be considered more up to date. If you run into a species identified from a field guide that doesn’t seem to be in the VASCAN drop-down list, use an internet connection to look up synonyms on the VASCAN website and obtain the accepted species name.
?. [Survey Trees within each Plot]
If the Postex system is unable to take a distance measurement (e.g., tree density is too high), use the Laser Geo to measure Distance from center and Compass bearing. To do so, aim the Laser Geo from the DBH of tree* towards the center of the Postex tripod and use the DME function to measure distance from center (m) and Compass function to get the compass bearing (°). Record these these values under Vegetation Surveys: Large trees  → Surveyed trees  → Location. *In the middle of the trunk laterally, with the Laser Geo resting on the side of the tree to be able to aim. In 2019, we did not take into account the radius of the tree as, in dense forests where the Postex system was unable to work, most trees had a small DBH (
?. [Postex Setup]
Setup the Postex system, please refer to the Postex System User Guide.
?. [Plot Creation and Measurements]
Establish the plot in the field by permanently marking the plot center with rebar (90 cm long) topped with an orange safety cap. Be sure the rebar is inserted into the ground deeply enough to be sturdy. Label the cap with the plot number and mark the rebar with a piece of duct-tape labeled with: CABO - Plot number - Initials of the people establishing the plot - Date.
?. [Plot Creation and Measurements]
Take plot-level measurements (e.g., slope and aspect).
?. [Plot Creation and Measurements]
Using the Angle and Compass functions of the Laser Geo, measure slope angle and aspect along two vectors per plot:        1) parallel to the steepest slope (shown in red in the figure below), and         2) any other secant vector (shown in white), crossing the first one.Take the slope angle and aspect measurements between two researchers who are standing along the vectors 7.5 m apart. The angle is in the direction from the higher position to the lower position along the slope.
For the slope angle measurements, the researcher using the Laser Geo should aim at the point equivalent to their eye-level on the other researcher.
For Compass measurements, AZ (azimuth) denotes bearing (i.e., compass degrees).
?. [Plot Creation and Measurements]
Under Plots → Optional Plot Info, save the slope angles (Slope 1 and Slope 2) and aspects (Bearing 1 and Bearing 2).
?. [Plot Creation and Measurements]
Save the newly created plot and its associated plot-level data.
?. [Survey Trees within each Plot]
Repeat steps 9.1-9.9 for every tree in the plot that meets the selection criteria.
?. [Next Plot]
Survey the next plot by following steps 3 to 9 over again.
?. [Plot Creation and Measurements]
Divide the plot in sampling sections to help keep track of your progression within the survey plot.
?. [Rare Trees Survey outside Plots (Megantic Only)]
Georeference these trees under Plants → Location.
?. [Coordinates Conversion]
Once the field season is over, calculate the X-Y coordinates of the trees which had their coordinates taken using the Laser Geo (see step 9.4).
?. [Coordinates Conversion]
In Fulcrum → Vegetation Surveys: Large Trees, export your data of interest in .csv.Select the appropriate project or site.  Click on "Download data". Indicate the "CSV (.csv)" fomat, then click "Start".   Click on the "..." icon –a drop-down menu will appear. Click on the name of the file you just created.  A download window will appear. Click on "OK".  Extract your compressed file, then open the "vegetation_surveys_large_trees_surveyed_trees.csv" file using Excel.Click on "Download data". Indicate the "CSV (.csv)" fomat, then click "Start".   Click on the "..." icon –a drop-down menu will appear. Click on the name of the file you just created.  A download window will appear. Click on "OK".  Extract your compressed file, then open the "vegetation_surveys_large_trees_surveyed_trees.csv" file using Excel.Click on the "..." icon –a drop-down menu will appear. Click on the name of the file you just created.  A download window will appear. Click on "OK".  Extract your compressed file, then open the "vegetation_surveys_large_trees_surveyed_trees.csv" file using Excel.A download window will appear. Click on "OK".  Extract your compressed file, then open the "vegetation_surveys_large_trees_surveyed_trees.csv" file using Excel.
?. [Coordinates Conversion]
In Excel, filter the distance_from_center_m column to remove (untick) the "Empty" values, then click "OK".
?. [Coordinates Conversion]
In Excel, caclulate X-Y coordinates of these trees using the following formulas:x = - L * sinΘy = - L * cosΘwith:x = x_position_my = y_position_mL = Distance_from_center_mΘ = Compass_bearing_rad
?. [Coordinates Conversion]
In Fulcrum → Vegetation Surveys: Large Trees → Survey → Surveyed Trees → [Record] → Location, edit the appropriate trees by adding their X-Y coordinates. Then, to avoid confusion, remove their Distance from center (m) and Compass bearing (°). Do so one Vegetation Survey at a time, saving your record when you're done.
?. [Coordinates Conversion]
In Excel, create a new column titled compass_bearing_rad_, with its cells containing the formula "=AL28*PI()/180" to convert degrees to radian.Where AL28 is the name of the adjacent cell containing the compass_bearing_deg* value for a given tree.*This has been measured from the tree to the plot center, with North = 0°, East = 90° and so forth.
?. [Fieldwork Preparation]
To measure true north (vs magnetic north), the Laser Geo needs to be setup with the local magnetic declination. Find the updated magnetic declination of your field site by locating it on http://www.magnetic-declination.com/. This has to be done shortly before fieldwork, as magnetic declination changes with time. Enter this value in the Laser Geo under Settings → Magnetic declination.