Short-term effects of fire and forest thinning on truffle abundance and consumption by Neotamias speciosus in the Sierra Nevada of California

2005 ◽  
Vol 35 (5) ◽  
pp. 1061-1070 ◽  
Author(s):  
Marc D Meyer ◽  
Malcolm P North ◽  
Douglas A Kelt

In many western North American forests, prescribed burning and mechanical thinning are widely used to reduce fuels and restore stand conditions after a century of fire suppression. Few studies have followed the relative impacts of these treatments on the production and consumption of truffles in forest ecosystems, particularly in the Sierra Nevada of California. Using a full-factorial completely randomized design, we examined the short-term impacts of prescribed burning (no burn and burn), mechanical thinning (no thin, light thin, and heavy thin), and combinations of these treatments on the production of truffles and their consumption by lodgepole chipmunks (Neotamias speciosus Merriam) in a mixed-conifer forest of the southern Sierra Nevada of California. Truffle frequency, biomass, and species richness were lower in thinned or burned plots than controls, as was the frequency and generic richness of truffles in the diet of N. speciosus. Truffle frequency, biomass, and species richness, and truffle consumption by N. speciosus were lower in heavily thinned and thinned and burned plots than in those exclusively burned. These results suggest that either thinning or burning can reduce short-term truffle production and consumption, and potentially the dispersal of ectomycorrhizal spores by small mammals. Moreover, truffles decreased with treatment intensity, suggesting heavy thinning and higher burn intensity, particularly when applied together, can significantly affect short-term truffle abundance and small mammal consumption.

2020 ◽  
Author(s):  
Zachary Steel ◽  
Marissa Goodwin ◽  
Marc Meyer ◽  
G. Andrew Fricker ◽  
Harold Zald ◽  
...  

Climate change is amplifying the frequency and severity of droughts and wildfires in many forests. In the western U.S., fuels reduction treatments, both mechanical and prescribed fire, are widely used to increase resilience to wildfire but their effect on resistance to drought and beetle mortality is not as well understood. We followed more than 10,000 mapped and tagged trees in a mixed-conifer forest following mechanical thinning and/or prescribed burning treatments in 2001 through the extreme 2012-2016 drought in California. Mortality varied by tree species from 3% of incense-cedar to 38% of red fir with proportionally higher mortality rates in the larger size classes for sugar pine, red fir and white fir. Treatment reductions in stem density were associated with increased diameter growth and rapidly growing trees had lower rates of mortality. However, the ultimate effects of treatment on drought-related mortality varied greatly by treatment type. All species had neutral to reduced mortality rates following mechanical thinning alone, but treatments that included prescribed burning increased beetle infestation rates and increased mortality of red fir and sugar pine. Fuels reduction treatments appear to benefit some species such as Jeffrey pine, but can reduce resistance to extreme drought and beetle outbreaks in other species when treatments include prescribed burning. In a non-analog future, fuels reduction treatments may require modification to provide resistance to beetle infestation and severe droughts.


2016 ◽  
Vol 46 (5) ◽  
pp. 745-752 ◽  
Author(s):  
Carrie R. Levine ◽  
Flora Krivak-Tetley ◽  
Natalie S. van Doorn ◽  
Jolie-Anne S. Ansley ◽  
John J. Battles

In the western United States, forests are experiencing novel environmental conditions related to a changing climate and a suppression of the historical fire regime. Mixed-conifer forests, considered resilient to disturbance due to their heterogeneity in structure and composition, appear to be shifting to a more homogeneous state, but the timescale of these shifts is not well understood. Our objective was to assess the effects of climate and fire suppression on stand dynamics and demographic rates of an old-growth mixed-conifer forest in the Sierra Nevada. We used a Bayesian hierarchical analysis to quantify species and community rates of recruitment, growth, and mortality. Despite a warming climate, we found that stand density, basal area, and carbon have increased over 56 years. Fir recruitment and growth significantly exceeded the community-level median rates, whereas pine recruitment and growth was significantly lower than the community-level median rates. Shifts in species composition from a well-mixed stand to a more dense fir-dominated stand appear to be driven by low growth and recruitment rates of pines relative to firs. In forests such as these with consistent and relatively low mortality rates, we recommend that restoration and management activities be focused on promoting pine recruitment and growth.


2006 ◽  
Vol 15 (1) ◽  
pp. 31 ◽  
Author(s):  
Chad T. Hanson ◽  
Malcolm P. North

In California’s mixed-conifer forest, which historically had a regime of frequent fires, two conifers, Sequoiadendron giganteum and Pseudotsuga menziesii, were previously known to produce epicormic sprouts from branches. We found epicormic branching in a third mixed-conifer species, Abies concolor, 3 and 4 years after a wildfire in the central Sierra Nevada Mountains of California. Sprouting occurred only from the boles. We investigated (1) whether the degree of crown loss and the extent of epicormic branching were independent; and (2) whether epicormic branching differed by tree size. The vertical extent of epicormic foliage increased with increasing severity of crown loss. There was a significantly greater proportion of large diameter-class (>50 cm diameter at breast height [dbh]) trees with epicormic branching than small/medium diameter-class (25–50 cm dbh) trees. These results suggest large diameter Abies concolor may survive high levels of crown loss, aided by crown replacement through epicormic branching, but that reiterative green foliage may not appear for up to 3 years after fire damage. If this response is widespread, it would suggest some ‘dying’ trees logged under current salvage guidelines could survive, and that higher-intensity fire may substantially reduce the density of small post-fire suppression white fir, while retaining many larger overstory trees.


PLoS ONE ◽  
2015 ◽  
Vol 10 (8) ◽  
pp. e0135014 ◽  
Author(s):  
Morgan L. Wiechmann ◽  
Matthew D. Hurteau ◽  
Jason P. Kaye ◽  
Jessica R. Miesel

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