Tree regeneration and soil responses to management alternatives in beetle-infested lodgepole pine forests

Rocky Mountain forests are poised to recover following bark beetle outbreaks but with altered composition

“…aspen, Engelmann spruce, lodgepole pine and subalpine fir; Peet, 1981; Romme et al, 2009). At the individual‐tree level, we summarized height growth rates (average cm yr −1 ) for the three dominant coniferous species based on methods used in individual studies – that is, internode measurements of annual growth (Andrus, Hart, & Veblen, 2020; Harvey et al, 2021; Rhoades et al, 2020) or repeated surveys (Pappas et al, 2020) – across a subset of field plots ( n = 254) that spanned the SRM. Height growth rates of aspen were excluded from our analyses due to insufficient sample size and a growth form that precludes the use of internode measurements.…”

“…We compiled field datasets that were collected for 16 studies of bark beetle effects on subalpine forests throughout the SRM (Andrus, Chai, et al, 2021; Andrus, Hart, & Veblen, 2020; Audley et al, 2020; Carlson et al, 2020; Carter et al, 2022; Chapman, Unpublished Data; Coop et al, Unpublished Data; Fornwalt et al, 2018; Gill et al, 2017; Harvey et al, 2021; Morris et al, 2022; Nigro et al, 2022; Pappas et al, 2020; Redmond & Kelsey, 2018; Rhoades et al, 2020; Schapira, Stevens‐Rumann, Shorrock, Hoffman, & Chambers, 2021). This combined dataset includes 969 field plots with nearly 40,000 records of trees (≥3 m in height) and saplings (≥1.4 m and <3 m), tallies of over 40,000 juveniles (<1.4 m) and height growth rates for nearly 2000 saplings and juveniles (Figure 1; Appendix S1).…”

Sources of variability in springwater chemistry in Fool Creek, a high‐elevation catchment of the Rocky Mountains, Colorado, USA

“…We observed decreased down‐gradient NO 3 − concentrations in both spring and streamwater (Figure 6 and Table 1) and TDN was also highest in the Upper zone springs (Table 2). Fraser catchments in general, and Fool Creek specifically, release little N even after forest dieback (Rhoades et al, 2017) or logging (Rhoades et al, 2020). The decline in N at lower elevations is consistent with the high plant N demand typical of subalpine forests (Fahey & Knight, 1986), as shown by low soil solution NO 3 − exported from the rooting zone (Table 1).…”

Impacts of harvesting practices on nutrient balances of forests under high nitrogen deposition

“…However, contrasting findings suggest that stem-only harvest may lead to lower nutrient leaching from soils due to nutrient immobilization by microbes (Gundersen et al, 2006). Furthermore, Harvest residues left on the site can hinder the establishment of regeneration while soil preparation may stimulate the establishment of the regeneration (Collins et al, 2011;Rhoades et al, 2020;Kampherbeek et al, 2021). However, when regeneration has established, harvest residues can have a positive influence on seedling survival and growth (Heinemann and Kitzberger, 2006;Rhoades et al, 2020).…”

“…Furthermore, Harvest residues left on the site can hinder the establishment of regeneration while soil preparation may stimulate the establishment of the regeneration (Collins et al, 2011;Rhoades et al, 2020;Kampherbeek et al, 2021). However, when regeneration has established, harvest residues can have a positive influence on seedling survival and growth (Heinemann and Kitzberger, 2006;Rhoades et al, 2020). These conflicting responses underscore Chapter 6 the necessity for more experimental data across diverse forest systems to better comprehend the effects of harvest methods and soil preparation on post-harvest leaching.…”