Part of a series of articles titled Five-Needle Pine Monitoring on Wyoming Bureau of Land Management Forests in the Greater Yellowstone Ecosystem.
Article
White Pine Blister Rust Infection Status, Mortality, and Recruitment of Five-Needle Pines on Wyoming Bureau of Land Management Forests in the Greater Yellowstone Ecosystem—Data Summary of Monitoring in 2022
This is the second article in the article series, “Five-Needle Pine Monitoring on Wyoming Bureau of Land Management Forests in the Greater Yellowstone Ecosystem.” It summarizes data collected to meet the following four objectives of monitoring five-needle pine species on Wyoming Bureau of Land Management (BLM) forests in the Greater Yellowstone Ecosystem:
Objectives:
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Estimate the proportion of live, five-needle pine trees (>4 m tall) infected with white pine blister rust.
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Document blister rust infection severity by the occurrence and location of persisting and new infections.
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Determine mortality of five-needle pine trees and describe potential factors contributing to the death of trees.
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Assess the multiple components of the recruitment of understory five-needle pine into the reproductive population.
Within the study area of eight geographic strata, one panel containing two strata is sampled each year, for a four-year revisit schedule (see Methods article in this series). Each geographic stratum is considered a sample frame and may contain multiple map units. In 2022, we sampled one permanent transect in each of the two strata and up to 5 of 10 possible rapid transects for each map unit within a stratum on Panel 3, which includes the Pine Grove/Deadline Ridge and the Rattlesnake sampling frames (Table 1). This resulted in 58 total transects surveyed in 2022.
Sample Frame/ Geographic Stratum | Map Unit and Number of Transects Sampled within It | Number of Transects Visited but Not Sampled | Number of Transects Not Visited |
Pine Grove/Deadline Ridge | PGDR1 = 4* | 0 | 7 |
Pine Grove/Deadline Ridge | PGDR2 = 3 | 0 | 7 |
Pine Grove/Deadline Ridge | PGDR3 = 3 | 0 | 7 |
Pine Grove/Deadline Ridge | PGDR4 = 3 | 0 | 7 |
Pine Grove/Deadline Ridge | PGDR5 = 3 | 0 | 7 |
Pine Grove/Deadline Ridge | PGDR6 = 3 | 0 | 7 |
Rattlesnake | Rattle1 = 5* | 0 | 6 |
Rattlesnake | Rattle2 = 4 | 2 | 4 |
Rattlesnake | Rattle3 = 4 | 0 | 6 |
Rattlesnake | Rattle4 = 4 | 1 | 5 |
Rattlesnake | Rattle5 = 4 | 1 | 5 |
Rattlesnake | Rattle6 = 4 | 0 | 6 |
Rattlesnake | Rattle7 = 4 | 0 | 6 |
Rattlesnake | Rattle8 = 3 | 1 | 6 |
Rattlesnake | Rattle9 = 4 | 0 | 6 |
Rattlesnake | Rattle10 = 3 | 0 | 7 |
Sampling methods for each objective are detailed in the Methods article of this series. Results for past years are available on the Greater Yellowstone Network website, including a summary of results for 2013 to 2017 (Shanahan et al. 2022). We will revisit Wyoming BLM permanently established transects according to the panel schedule in the Methods article to conduct rapid assessment transects in those assigned map units within the targeted geographic strata. In addition, we will collect stand structure and composition information to inform potential silvicultural treatment opportunities for enhancement of five-needle pine on Wyoming BLM lands. Should we continue to note dwarf mistletoe infection in limber pine populations from targeted geographic strata, we may consider more in-depth data collection on this metric.
Results for Objective 1—White Pine Blister Rust Infection
Within permanent transects, all five-needle pine trees >1.4 m tall are tagged. Rapid assessment survey transects trees are not tagged and only a subset of individual tree measurements are recorded. Therefore, infection status is documented for all 58 transects, whereas change in infection status can only be documented in the two permanent transects.
Trees Infected with White Pine Blister Rust
We examined 1231 live tagged trees in the two permanent transects and 56 rapid assessment survey transects from Panel 3 for blister rust infection in 2022. A total of 627 (51%) trees were documented with blister rust infection and 604 (49%) had no infection present. Of these 627 infected trees, 326 (52%) had bole infections (Figure 1).
Change of Infection Status Over Time: Tagged Trees Live in 2018 and 2022
Because live tagged trees on the permanently established transects are visited every four years, infection transition can be documented through time. Infection transition is not reported for rapid transect data. Of the 79 live trees on the two permanent transects that were surveyed on Panel 3 transects in 2018 and again in 2022, approximately 31 (39%) had no evidence of blister rust infection, 21 (27%) were infected in both years, 26 (33%) transitioned from no evidence of infection to infected, and one (1%) went from infected to uninfected (Table 2). A transition from infected to uninfected could result from observer error, an earlier-documented infection based on indicators that upon resurvey no longer meet the established standards of three indicators in the same location, or infected branches that self-pruned.
Infection Status | Number of Live Trees (n = 79) |
Remained Uninfected | 31 (39%) |
Remained Infected | 21 (27%) |
Uninfected to Infected | 26 (33%) |
Infected to Uninfected | 1 (1%) |
Results for Objective 2—White Pine Blister Rust Infection Transition
On the two permanent transects, infection location changed for trees that were documented with blister rust in 2018 and again in 2022 (Figure 2). Three (27%) of the 11 trees with canopy only infections in 2018 that remained infected in 2022 transitioned to a more severe state of infection in the bole by 2022. This transition occurred in the larger size class trees, >10 cm DBH. One tree that was documented as infected in 2018 in the canopy was no longer observed with an infection anywhere on the tree in 2022 and one bole infected tree in 2018 was recorded as infected in the canopy only by 2022.
Results for Objective 3—Mortality
In 2022, we observed three new dead tagged trees on the two permanent transects (Figure 3). No obvious signs of mortality influencing agents (i.e., white pine blister rust, mountain pine beetle, fire) were observed on any of the dead trees. Dead trees are no longer recorded on rapid assessment survey transects.
Results for Objective 4—Recruitment
On both permanent and rapid transects, recruitment data are collected at two scales: the 10 × 50 m belt transects, and 1/300 acre subplots associated with the belt transects.
10 × 50 m Belt Transects
Regeneration and Growth
In 2022, we counted 1007 understory five-needle pines (≤1.4 m tall) on 58 transects (Table 3). This equates to an average density of approximately 17 small trees per transect. Fifty-two of these small trees were infected with blister rust, but blister rust status was indiscernible for an additional 40.
No new trees had surpassed 1.4 m tall since the last survey.
Sample Frame | Map Unit and Number of Transects Sampled | Number of Small Trees (<140 cm) | Number of Small Trees Infected | Number of Small Trees Uninfected | Number of Small Trees Infection Unknown |
Pine Grove/ Deadline Ridge | PGDR1 = 3 | 139 | 1 | 135 | 3 |
Pine Grove/ Deadline Ridge | Perm PGDR1-71 = 1 | 62 | 0 | 62 | 0 |
Pine Grove/ Deadline Ridge | PGDR2 = 3 | 77 | 20 | 39 | 18 |
Pine Grove/ Deadline Ridge | PGDR3 = 3 | 38 | 3 | 31 | 4 |
Pine Grove/ Deadline Ridge | PGDR4 = 3 | 68 | 16 | 43 | 9 |
Pine Grove/ Deadline Ridge | PGDR5 = 3 | 63 | 2 | 61 | 0 |
Pine Grove/ Deadline Ridge | PGDR6 = 3 | 98 | 6 | 86 | 6 |
Rattlesnake | Rattle1 = 4 | 46 | 0 | 46 | 0 |
Rattlesnake | Perm Rattle-171 = 1 | 3 | 0 | 3 | 0 |
Rattlesnake | Rattle2 = 4 | 7 | 0 | 7 | 0 |
Rattlesnake | Rattle3 = 4 | 241 | 0 | 241 | 0 |
Rattlesnake | Rattle4 = 4 | 21 | 0 | 21 | 0 |
Rattlesnake | Rattle5 = 4 | 70 | 1 | 69 | 0 |
Rattlesnake | Rattle6 = 4 | 15 | 3 | 12 | 0 |
Rattlesnake | Rattle7 = 4 | 23 | 0 | 23 | 0 |
Rattlesnake | Rattle8 = 3 | 2 | 0 | 2 | 0 |
Rattlesnake | Rattle9 = 4 | 15 | 0 | 15 | 0 |
Rattlesnake | Rattle10 = 3 | 19 | 0 | 19 | 0 |
Cone Production
Cone production evidence (current year cones, previous year cone scars, or male pollen cones) was recorded for 251 trees in 2022 (Figure 4). Reproducing trees ranged across the four DBH size classes. Of the trees with cone evidence, 133 (53%) had signs of blister rust infection.
For reproducing trees, cones are counted and categorized into five bins: 0 = no cones, 1 = 1–5 cones visible, 2 = 6–10 cones visible, 3 = >10 cones visible, and S = cone scars but no current year cones visible. Of the Panel 3 trees documented with cones, the largest number, at 129 (51%), fall into the 1–5 cone category, while 51 trees were observed with >10 cones. By tracking cone production over time, we will gain valuable insight on the trajectory of future five-needle pine recruitment.
1/300 acre Recruitment Subplots
In 2022, we completed 174 recruitment subplots (three per transect). In these 1/300 acre recruitment subplots, we recorded the number of five-needle pines in four height categories (>0–15 cm, 15.1–61 cm, 61.1–140 cm, >140 cm; note that trees in the >140 cm category typically have tags already if they are within the 10 × 50 m transect boundary). All other tree species (lodgepole pine (Pinus contorta), fir (Abies lasiocarpa, Pseudotsuga menziesii), spruce (Picea engelmannii), and sometimes aspen (Populus tremuloides)) are recorded in two height categories (15–140 cm, >140 cm). We examined each five-needle pine tree for signs of blister rust. In addition, we recorded ground cover, vegetation cover, and dominant and codominant vegetation species.
Data for recruitment subplots are under review, and summary information will be part of a future update to this web article.
Learn More
This web article will be updated periodically with new results. Results for 2022 are summarized in a resource brief for 2022. For more results from past years please visit the Greater Yellowstone Network website.
Last updated: April 17, 2023