Attachment_3-Interagency_Standardized_Protocol_for_Joshua_Tree_Monitoring.pdf

Interagency Standardized Protocol for Joshua Tree Monitoring NV AIM Version 03/12/2025

Plot Layout Joshua tree monitoring plots are 50x50 m square plots randomly distributed on the landscape in a spatially balanced manner appropriate for the study area. Locate plots with a north-south orientation aligned to 0° true North. If co-located with another plot of a different layout, overlay a square plot on that plot to enable regular seedling search effort.

Plot corners should be temporarily demarcated with pin flags (See Appendix A, Overlaying a Joshua tree plot on top of a 30m radius circular AIM plot).

Search For Trees Demarcate the edges and corners of the plot using a high accuracy (sub-meter or better) GPS device. If such device is not available, use a transect tape to locate the corners. Two opposite sides of the plot should be marked with flags every five meters to form 5-meter wide belts.

Where permitted, trees may be tagged individually with a metal tag, with one tag per individual tree. Tags may be nailed into the tree trunk at 0.25 m and facing away from roads and trails, or if not a factor on the north side of the tree. Nails should stick out from the tree slightly to allow growth or swelling of the trunk over time. Trees without a sufficient trunk may have a wire ring around the base that will not harm the plant. For NV AIM plots, we will not be placing metal tags on trees.

After all obvious trees have been measured, thoroughly search each belt transect for seedlings. Belt transects should be searched methodically on a zigzag pattern, taking time to search under the canopy of every shrub (large or small), open space between canopies, inside every perennial bunchgrass, and in crevices between rocks. Use a minimum of 5 minutes survey time for one person to survey a 5 m belt, increasing the time as necessary to thoroughly search areas with more dense vegetative cover.

Photos Take photos from the south side of each individual tree or rotate as needed if the tree cannot be clearly viewed from that angle.

Label all photos in the bottom right corner by digitally editing the photo with plot name, tree ID, and yyyymmdd date (e.g., “010_001_20240123”). Camera identifier and img# can be added to the data sheet. Digital photos should be stored with the photo name matching the photo label.

Tree Coordinates Record coordinates of each individual Joshua tree in Decimal Degrees (WGS84) using a high accuracy GPS device. Use waypoint averaging to average 25 points. Do not remeasure coordinates on repeat surveys unless there is an obvious error.

Status

Status Code Name Definition S Seedling An individual with less than 10 total leaves (live or dead) AND that has not been observed on any previous survey. See Special Cases: Seedling Clusters (p. 7)

J Juvenile An individual larger with more than 10 leaves but with no evidence of flowering on any stem

A Adult An individual where the parent stem is alive AND at least one stem has produced a flower stalk

RS Resprout The parent stem is dead AND at least one stem in the cluster is living AND none of the living stems have evidence of flowering

RR Reproductive Resprout

The parent stem is dead AND at least one stem in the cluster is living AND at least one of the living stems has evidence of flowering

D Dead All stems in the cluster are dead.

Dead Trees For dead trees or clusters with no live stems, record location and height (if measurable). Only measure height if the whole length of the tree is present. If the whole tree is present and broken into easily distinguished pieces, measure up to three pieces and add them together to match the height of the tree if it had been standing. If only the stump or only a portion of the tree is present, record only the coordinates and status of the tree and record NA for height.

Average Green Length (AGL)

Visually estimate the average length of the axis of each live terminal branch that is covered in green leaves (NOT the length of those leaves). The average green length considers only live branches, not accounting for dead. For clonal clusters with multiple stems, factor in all live terminal ends of stems in the cluster.

AGL is an ocular estimate meant to approximate these criteria—NOT a direct measurement. See sample photos on page 8-9.

AGL Code Description 5 Average green length on each branch is over 60 cm. For plants <60 cm in height, 95-100% of the stem is covered in green leaves.

4 Average green length on each branch is 45-60 cm.

For plants <60 cm in height, 75-95% of the stem is covered in green leaves.

3 Average green length on each branch is 30-45 cm.For plants <60 cm in height, 50-75% of the stem is covered in green leaves.

2 Live branches in the cluster have an average of 15-30 cm of green leaves.

For plants <60 cm in height, 25-50% of the stemis covered in green leaves.

1 Live branches of live stems in the cluster have an average below 15 cm of green leaves.

For plants <60 cm in height, 0.1-25% of the stemis covered in green leaves.

Number of Stems in Clonal Cluster Count all live and dead stems in the cluster. This includes the parent stem and any clonal basal sprouts associated with

it. Stems must be BOTH:

1. Distinct: Stems do not need to be physically separated from the parent tree but must enter the ground level separately from any other stem, such that the center of the stem is in contact with the ground and not in the trunk of any other neighbor, such that it has its own root system and could survive independently. If they do not meet this requirement, they are considered branches.

2. Proximate:

a. All plants that are within 1 m of another stem (measured horizontally from the inside edge of each tree) in a clonal cluster are part of that cluster. (EXCEPT see Special Cases: Seedling Clusters (p. 7)

b. Plants 1-2 m from the nearest stem in a clonal cluster are considered to be part of that cluster only if

BOTH of the following are true: neither is a pre-reproductive tree with a nurse plant AND there is a greater than 1 m difference in height between the stem in question and the tallest stem in the cluster.

c. Plants greater than 2 m from the nearest stem are always considered to be separate individuals.

Fig 1. Basal Sprout Examples.

• Trees 341A and 341B are basal sprouts because they are within 1m of the nearest stem in the cluster.

• Tree 341C is a basal sprout because it is 1-2 m from the nearest stem (341B), it is more than 1m shorter than the parent tree

(341), AND it has no nurse plant.

• Tree 342 is a separate tree because it is 1-2 m from the nearest stem (341) but it is less than 1 m shorter than the parent.

• Tree 343 is a separate tree because it is 1-2 m from the nearest stem (342) but it has a nurse plant.

Height

• Record the lean height of the tree following the leaning axis of the main stem. Place the base of the telescoping pole (avalanche pole) at the base of the tree and extend the pole through the canopy until the top of the pole is perpendicular to the highest leaf or dead branch, guided by a second observer standing at least 30 feet away from the tree and uphill if possible. If passing the pole through the canopy is not possible, offset the minimum distance necessary and ensure the base of the pole is level with the base of the tree.

• For fallen trees, measure the length of the tree horizontally as it would have been if it was standing.

• Height measurements should be a single straight-line measurement except for abnormal growth trees. See

Special Cases: Abnormal Growth (p. 7) for details on how to measure these trees.

Height to First Flower Stalk (HTFFS)

• Measure only for western Joshua tree (Yucca brevifolia). Note: USDA Plants still considers eastern and western Joshua trees to be the same species (YUBR). In Nevada, western Joshua trees are found in the Battle Mountain District, and in Tikaboo Valley (Ely District), where they mix with and hybridize with eastern Joshua trees.

Eastern Joshua trees are found in the Southern NV District, and in the Ely District.

• Record the length of the main trunk of the tree from the ground to the base of the first flower stalk, following any lean

• If there is no visible flower stalk or scar, record height to the top of the fork where the flower stalk would have been

• If the first flower stalk produced a direction change in the main stem but no new branching, measure to the outside edge of the bend where the flower stalk would have been (a scar should be visible).

Fig 2. For leaning stems, measure lengthwise along trunk (as shown on left), not vertically (right).

Fig. 3: Example of a flower stalk scar without additional branching.

Number of Terminal Ends

• Count the number of terminal ends (“branch tips”) on every stem in the cluster, including basal sprouts.

Terminal ends are any tip where a new crown of leaves is growing.

• When Joshua trees flower, the flower stalk occupies the apical meristem, preventing further growth in that direction. One, two or more branch tips sprout from the leaves below the flower stalk. Look closely to find these new branch tips.

• If a branch has flowered but has no new leaf/branch shoots forming at the base of the flower, count that as one terminal branch. If the branch has one set of new leaf shoots growing out, still count that as one terminal branch. If there are two or more clusters of leaf shoots growing from near the base of a flower stalk, count those two or more shoots as the number of terminal ends on that branch.

• Separate the branch ends into Living and Dead.

• If dead branches are broken off and scattered on the ground, count or estimate the number of dead terminal ends including what is visible on the ground.

• Two field technicians should independently count the number of live and dead terminal ends using the above process.

• For trees with fewer than 20 total terminal ends, the technicians should discuss and agree on a final count.

• For larger trees, the technicians should compare their final counts to see if they are within a 1/3 margin (if the difference between the two counts is less than one third of the smaller of the two counts). If not, the two technicians must carefully recount the number of terminal ends. Once differences are below the 1/3 margin, average the two counts to determine the final number of terminal ends.

Nurse Plants

Record the nurse plant species or USDA plant code for all seedlings or juveniles. A nurse plant is any perennial species whose canopy extends at least partly over the top of the juveniles or around the sides. Do not count other Joshuas trees as nurse plants..

Additional codes:

UNKS-D Unknown dead shrub OPEN Plants in the open or with only annual plants surrounding UNKG-D Unknown dead bunchgrass ROCK Plants sheltered by a rock or rock crevice

Seedling/Young Juvenile Leaf Counts

Count the number of live and dead leaves present on all individuals with less than 30 total leaves.

Damage Codes

Record damage codes with the four-letter code followed by a numerical rating (1-5) for severity. For example, a severely burned tree would be coded as BURN5. For very minor damages that fall below the level 1 threshold described below, do not record damages. ABGR and FALL do not have severity associated.

Code Definition Level 1 Level 2 Level 3 Level 4 Level 5

WOUN Open wound or cavity in the trunk penetrating through periderm and revealing tissues below.

Unhealed wounds affecting 1-2% of the main trunk

2-5% 5-10% 10-15% Unhealed wounds affecting over 15% of the main trunk

BRAN Broken branches (indicates terminal bud counts might be inaccurate)

3-20% of branches missing

20-40% 40-60% 60-80% 80-100% of branches missing

BARK Large area of missing periderm due to causes other than fire

3-20% of periderm missing

20-40% 40-60% 60-80% 80-100% of periderm missing

BURN Periderm burned away, not including charred periderm that is still covering the tree (do not code BARK for fire damage)

3-40% of periderm burned away

20-40% 40-60% 60-80% 80-100% of periderm burned away

HERB Herbivory—leaves chewed or cut by animals

3-20 % of leaves herbivorized

20-40% 40-60% 60-80% 80-100% of leaves herbivorized

GNAW Rodent damage to base of trunk— periderm/trunk gnawed at base or trunk hollowed out

Damage affecting <5% of periderm circumference

5-50 % of periderm, no tissues below impacted

50-100% of periderm circumference affected, only light damage to tissues below

Damage extends deeply to underlying tissues

Damage affecting >50% of the thickness of the trunk. Toppling imminent or has already occurred (code FALL if applicable).

WEEV Weevil Damage. Weevils present on stem or flowering branch ends felled by weevils

Weevils present, no obvious damage

Partial damage only

1 branch tip removed by weevils

2 branch tips removed

3 or more branch tips removed by weevils

BIRD Woodpecker damage— portion of trunk covered with holes

3-40% of trunk/primary branches affected

20-40% 40-60% 60-80% 80-100% of trunk/primary branches affected

LEAN Leaning tree 20-30° lean off vertical

30-40° 40-50° 50-60° >60° lean, not resting on ground

FALL Tree is fallen for any reason, with trunk or branches resting on the ground

N/A N/A N/A N/A N/A

ABGR Main stem of tree bent or irregular not as a result of flowering—see Special Cases: Abnormal Growth (p. 7)

N/A N/A N/A N/A N/A

OTHR Other damages (please note)

Very Low Low Moderate High Severe

Glossary

Term Definition Average Green Length

The length along the primary axis of each branch that is covered by green leaves, averaged across the whole tree (including dead branches as having a green length of zero). This is an ocular estimate (NOT a measurement) meant to approximate if it were possible to measure every branch.

Branch/Terminal End

A live terminal end is any branch end where new leaves might grow. This includes an apical meristem where new leaves are growing OR an apical meristem where new vegetative growth is blocked by a flower stem and which has not yet sprouted any new branches. A dead terminal end is the same but with no green leaves. A branch is a section of woody material on a unique axis bearing terminal ends or additional branches.

Evidence of Flowering

Evidence that the tree has ever flowered: presence of a dead flowering or fruiting stalk or a visible scar from the same, or a branching pattern obviously indicative of flowering.

Live/Dead Stem Live stems or branches have at least one green leaf connected through the stem to the ground. This includes cases where the trunk might be partially damaged. Dead stems have no green on any leaf that is connected to the ground.

Nurse Plant A nurse plant is any perennial species whose canopy extends at least partly over the top of the juveniles or around the sides.

Parent Stem The oldest stem in a cluster, live or dead. Generally assumed to be the largest stem by basal diameter when the cluster is first measured. Exception: if it is obvious that a smaller stem is older (for example, due to fire scarring), then record that as the parent stem.

Periderm The outer bark of the tree, made of a dark, rough material and surrounding the softer, lighter colored, interior of a Joshua tree. In Joshua trees, the periderm is often partially covered by a layer of dead leaves.

Individual Tree A single biological individual of the species Yucca brevifolia or Yucca jaegeriana, including the parent stem and any basal sprouts originating from that stem, regardless of the growth form of the plant.

Special Cases Abnormal Growth (ABGR): When trees are bending, sagging, or flopping over, take the two straight-line measurements that best capture the length of the main axis of the tree, and add these two measurements together to determine height (Fig. 3). Do not take more than two measurements, as this would exaggerate the height of the tree. Ignore any branches sprouting out of the main bend of the tree unless one of them is substantial enough to be considered the main stem.

Fallen: For measuring height, treat as either a lean tree or a flattened “n” shaped tree, depending on the situation, meaning that height can be measured using either one or two straight line measurements. New vertical growth from the bend should not be included for height unless it is longer than the remainder of the tree length.

Seedling Clusters Joshua tree seedlings often become established in tight clustered groups due to the way seeds or fruits are cached by rodents. These individuals can coexist until a young juvenile stage but are too tightly packed to establish a stem.

Record a seedling cluster if ALL of the following are true:

1. There is no evidence of a dead parent stem.

2. All stems appear to be the same age (eg. no significant difference in height, one is not burned)

3. All stems in the cluster are less than 50 cm tall.

4. All stems in the cluster are within 10 cm of the nearest neighboring stem

Seedling cluster procedure:

1. Record the number of distinguishable seedlings in the seedling cluster column on the datasheet.

2. Take leaf count and height measurements as described under seedling measurements on only the tallest seedling in the cluster.

3. Record any additional seedlings with >10 cm separation as distinct individuals.

Fig 4. Total height for ABGR trees is the sum of two straight-line measurements. If the new shoot on left (circled in red) were longer than H2, then it would be measured as part of the main stem instead of H2. Height = H1 + H2

Average Green Length Sample Photos:

AGL 5/5:

AGL 4/5:

AGL 3/5:

AGL 2/5:

AGL 1/5

Appendix A: Overlaying a Joshua Tree Demographic Plot on top of a 30m radius AIM Plot For 2025, AIM crews will likely not have access to a high accuracy (sub-meter) GPS. AIM crews will need to rely on their tablets for GPS, which generally have a 3-5m accuracy. However, it is important to ensure that no Joshua trees outside of the plot are included, and that no Joshua trees within the plot but near the edge are missed simply due to GPS inaccuracy.

Another difference between AIM plots and Joshua tree Demographic plots is the use of compass declination in setting up the transects and plot corners. AIM plots do not use declination, but the square Joshua tree plots are to be set up oriented north-south using true north. In Nevada and within Joshua tree habitat, declination ranges from 10.5 degrees in the southern tip of the state, to 11 degrees in the eastern portion, and 12 degrees in the far west portion of the Joshua tree range (near Lida, NV). Please do not adjust your compass for declination; instead adjust your azimuths by subtracting 11 degrees (e.g. True north on your compass is a 349 degree azimuth).

There are two basic methods to determine if individual Joshua trees are within or outside of the 50x50m square plot dimensions: 1) demarcating flags in the corners of the plots and along the edges in between the corners and 2) recording a distance and azimuth to trees near the edge of the plot (within 2m). Flags can be demarcated in the corners using tapes and a compass without declination set as shown in Figure 5:

Figure 5: Overlaying a Joshua tree Demographic Plot on top of an AIM plot