Twentieth-century decline of large-diameter trees in Yosemite National Park, California, USA

Lutz, James A.; Wagtendonk, Jan W. van; Franklin, Jerry F.

doi:10.1016/j.foreco.2009.03.009

Cited by 103 publications

(115 citation statements)

References 58 publications

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“…The constructed variables were: tree density for all trees and partitioned into four dbh classes, proportion of stand basal area by four species groups, derived canopy cover, live tree carbon, and density of large pines. The four dbh classes used to report partitioned tree density were: 15.2-30.4 cm, 30.5-61.0 cm, 61.1-91.4 cm, .91.4 cm, and were based on a stand classification scheme used in forest management throughout the Sierra Nevada (USDA 2004) and in previous work (Lutz et al 2009). The four species groups that we investigated for potential changes in proportion of stand basal area were: (1) pine-ponderosa pine and sugar pine, (2) true fir-white fir and red fir, (3) incensecedar, and (4) Douglas-fir.…”

Section: Discussionmentioning

confidence: 99%

“…These datasets allow for detailed quantitative comparisons of current vs. historical forest structure and composition (Stephens 2000, Lutz et al 2009). However, there are a number of concerns associated with historical datasets: (1) limited geographic extent, (2) unknown or unrepeatable study site selection/inventory methodologies, (3) uncertainty in accurately re-locating sampled areas (Kelly et al 2008), and (4) limited temporal depth.…”

Section: Introductionmentioning

confidence: 99%

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Impacts of fire exclusion and recent managed fire on forest structure in old growth Sierra Nevada mixed-conifer forests

2011

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Abstract. We re-sampled areas included in an unbiased 1911 timber inventory conducted by the U.S.Forest Service over a 4000 ha study area. Over half of the re-sampled area burned in relatively recent management-and lightning-ignited fires. This allowed for comparisons of both areas that have experienced recent fire and areas with no recent fire, to the same areas historically based on early forest inventories. Our results indicate substantially altered present forest conditions, relative to the 1911 data, and can largely be attributed to the disruption of the key ecosystem process for these forests, fire. For areas that burned recently there was a noticeable difference in forest structure based on fire severity. Current tree density and canopy cover in areas burned recently with moderate severity did not differ from 1911 estimates, while areas that burned recently with low severity or were unburned had higher tree density and canopy cover relative to the 1911 estimates. This emphasizes an important distinction with regard to using fire to restore forests, resting primarily on whether fires kill trees in the lower and intermediate canopy strata. Our results also demonstrate nearly a doubling of live tree carbon stocks in the present forest compared to the historical forest. The findings presented here can be used by managers and ecologists interested in restoring Sierra Nevada mixed conifer systems.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impacts of fire exclusion and recent managed fire on forest structure in old growth Sierra Nevada mixed-conifer forests

2011

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“…Changes to structure and composition of California forests.-Comparison of the VTM plots with current vegetation (using both relocated plots and contemporary vegetation maps) revealed consistent evidence of an increase in young-growth and small-diameter trees across the state and decreases in large trees (Minnich et al 1995;Fellows and Goulden 2008;Goforth and Minnich 2008;Lutz et al 2009;Dolanc et al 2013aDolanc et al , 2014McIntyre et al 2015), as well as changes in forest composition (Minnich et al 1995;Dolanc et al 2013a;McIntyre et al 2015). Much of this evidence of change in forest age structures derives from resurveyed VTM plots (Table 1).…”

Section: Th Century Changes To Vegetation Communitiesmentioning

confidence: 89%

“…The plots cover a gradient of vegetation types and include data regarding tree stand structure (number per diameter class), percent cover of dominant overstory and understory vegetation by species, soil type, parent material, leaf litter, elevation, slope, aspect, parent material, and other environmental variables. All plot data were stored on paper data sheets and individual plots were numbered according to map name, quad section Goforth and Minnich 2008;Fellows and Goulden 2008;Lutz et al 2009;Lutz et al 2010;Swanson et al 2013;Dolanc et al 2013a;Dolanc et al 2013b;Dolanc et al 2014;Maxwell et al 2014Walker 2000* Dodge 1975Taylor 2000 Conifer and hardwood forest Crimmins et al 2011;Dobrowski et al 2011;Crimmins et al 2013;Crimmins et al 2014 None None Land cover 6 Plots: Maps:…”

Section: Plot Data and Plot Mapsmentioning

confidence: 99%

“…They attributed this change to fire suppression. Lutz et al (2009) compared 655 VTM and 210 modern vegetation plots surveyed by National Park Service field crews from 1988-1999 in Yosemite National Park. They found that largediameter tree density in Yosemite declined by 24%, and declines were greatest in subalpine and upper montane forests, and least in lower montane forests.…”

Section: Th Century Changes To Vegetation Communitiesmentioning

confidence: 99%

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Rescuing and Sharing Historical Vegetation Data for Ecological Analysis: The California Vegetation Type Mapping Project

Kelly¹

2016

Biodiv. Inf.

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Abstract.-Research efforts that synthesize historical and contemporary ecological data with modeling approaches improve our understanding of the complex response of species, communities, and landscapes to changing biophysical conditions through time and in space. Historical ecological data are particularly important in this respect. There are remaining barriers that limit such data synthesis, and technological improvements that make multiple diverse datasets more readily available for integration and synthesis are needed. This paper presents one case study of the Wieslander Vegetation Type Mapping project in California and highlights the importance of rescuing, digitizing and sharing historical datasets. We review the varied ecological uses of the historical collection: the vegetation maps have been used to understand legacies of land use change and plan for the future; the plot data have been used to examine changes to chaparral and forest communities around the state and to predict community structure and shifts under a changing climate; the photographs have been used to understand changing vegetation structure; and the voucher specimens in combination with other specimen collections have been used for large scale distribution modeling efforts. The digitization and sharing of the data via the web has broadened the scope and scale of the types of analysis performed. Yet, additional research avenues can be pursued using multiple types of VTM data, and by linking VTM data with contemporary data. The digital VTM collection is an example of a data infrastructure that expands the potential of large scale research through the integration and synthesis of data drawn from numerous data sources; its journey from analog to digital is a cautionary tale of the importance of finding historical data, digitizing it with best practices, linking it with other datasets, and sharing it with the research community.

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Crowding, climate, and the case for social distancing among trees

Furniss

Das

Mantgem

et al. 2022

Ecological Applications

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In an emerging era of megadisturbance, bolstering forest resilience to wildfire, insects, and drought has become a central objective in many western forests. Climate has received considerable attention as a driver of these disturbances, but few studies have examined the complexities of climate–vegetation–disturbance interactions. Current strategies for creating resilient forests often rely on retrospective approaches, seeking to impart resilience by restoring historical conditions to contemporary landscapes, but historical conditions are becoming increasingly unattainable amidst modern bioclimatic conditions. What becomes an appropriate benchmark for resilience when we have novel forests, rapidly changing climate, and unprecedented disturbance regimes? We combined two longitudinal datasets—each representing some of the most comprehensive spatially explicit, annual tree mortality data in existence—in a post‐hoc factorial design to examine the nonlinear relationships between fire, climate, forest spatial structure, and bark beetles. We found that while prefire drought elevated mortality risk, advantageous local neighborhoods could offset these effects. Surprisingly, mortality risk (Pm) was higher in crowded local neighborhoods that burned in wet years (Pm = 42%) compared with sparse neighborhoods that burned during drought (Pm = 30%). Risk of beetle attack was also increased by drought, but lower conspecific crowding impeded the otherwise positive interaction between fire and beetle attack. Antecedent fire increased drought‐related mortality over short timespans (<7 years) but reduced mortality over longer intervals. These results clarify interacting disturbance dynamics and provide a mechanistic underpinning for forest restoration strategies. Importantly, they demonstrate the potential for managed fire and silvicultural strategies to offset climate effects and bolster resilience to fire, beetles, and drought.

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Twentieth-century decline of large-diameter trees in Yosemite National Park, California, USA

Cited by 103 publications

References 58 publications

Impacts of fire exclusion and recent managed fire on forest structure in old growth Sierra Nevada mixed-conifer forests

Impacts of fire exclusion and recent managed fire on forest structure in old growth Sierra Nevada mixed-conifer forests

Rescuing and Sharing Historical Vegetation Data for Ecological Analysis: The California Vegetation Type Mapping Project

Crowding, climate, and the case for social distancing among trees

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