Questions
Questions in this section frequently come up in workshops, field tours, symposia, and general discussions related to pinyon-juniper woodlands. They are closely linked to woodland ecology, resilience, resistance to invasives, and restoration. Most are addressed in more depth in referenced citations and Miller et al. 2019.
Soil water storage: During the spring, Utah junipers (Juniperus osteosperma) and western junipers (J. occidentalis) rapidly used soil water in the upper soil zone (<0.9 m [3 ft] deep) where soil nutrient concentrations are highest and most important for the majority of herbaceous species. In areas where trees have been removed, the growing season of…
In pinyon pines (Pinus monophylla and P. edulis), portions of three growing seasons are required to produce mature seeds. Pinyon seeds are short-lived with little inherent dormancy. In Utah (Juniperus osteosperma) and western junipers (J. occidentals), it takes two growing seasons following pollination to produce mature fruits. In contrast to pinyon, juniper often have long-lived seeds…
Many semi-arid communities are fuel limited, thus the accumulation of fine fuels during wet years increases fuel continuity at the landscape level and has been closely linked to large and widespread fires in semiarid ecosystems (Abatzoglou and Kolden 2013; Allen et al. 1995; Baisan and Swetnam 1997; Brown et al. 2008; Grissino-Mayer and Swetnam 2000;…
The amount of lateral leader growth on understory sapling-size trees is a good indicator of understory competition between overstory trees. Compare leader length in closed stands to trees growing in the open or at the edge of a stand or adjacent to a road.
There is a strong inverse relationship between the tree overstory and understory including shrubs and perennial grasses and forbs. Shrubs rarely persist beneath a closed tree canopy, especially sagebrush. However, deep rooted perennial grasses have been observed to persist where soils are moderately deep to deep and where restrictive layers (e.g. clay accumulation layer called…
Locations with relatively warm fall temperatures (examples are the Columbia, Snake, and Humboldt basins) are especially susceptible to cheatgrass (Bromus tectorum) dominance, while those with cooler fall seasons and relatively wet winters and springs are more resistant to cheatgrass (Bradley et al. 2016; Cline et al. 2018).
In the first few growing seasons fire results in: 1) reduced competition, 2) increased available nitrogen, and 3) warmer soil surface temperatures in the fall and early spring. Cheatgrass (Bromus tectorum) has higher nitrogen absorption rates than many native plants, where soils are warm and moist in the fall and spring (Roundy et al. 2020;…
- « Previous
- 1
- 2