Enlargement of canopy gaps associated with a fungal pathogen in Yosemite Valley, California

2000 ◽  
Vol 30 (10) ◽  
pp. 1501-1510 ◽  
Author(s):  
D M Rizzo ◽  
G W Slaughter ◽  
J R Parmeter, Jr.
Keyword(s):  
Contact Zone ◽  
Pinus Ponderosa ◽  
Tree Mortality ◽  
Host Density ◽  
Basal Area ◽  
Canopy Gaps ◽  
Heterobasidion Annosum ◽  
Conifer Forest ◽  
Yosemite Valley ◽  
Root Contact

The enlargement of 21 canopy gaps associated with the root pathogen Heterobasidion annosum (Fr.:Fr.) Bref. = Fomes annosus (Fr.) Karst.) in the mixed-conifer forest of Yosemite Valley was monitored between 1971 and 1998. Mean expanded gap area was 232 m2(range 38-802 m2) in 1971 and 1455 m2(range 150-4216 m2) in 1998. The pathogen is primarily spread among trees via root contacts; therefore, the spread and impact of H. annosum from the stump(s) where infection originated (gap makers) were characterized by describing the area of potential root contact as a variable-area plot. The potential root contact zone delineated the area that would be encompassed by mortality if all trees potentially in contact with the original gap makers had died. Of the 21 plots, the actual area of tree mortality exceeded the potential root contact zone in only two gaps. Enlargement rates around gap perimeters were uneven, ranging from 0 to 1.33 m/year. Incense-cedars (Calocedrus decurrens (Torr.) Florin) tended to die more slowly than ponderosa pines (Pinus ponderosa Dougl.), often 10-30 years after adjacent pines had died. Gap enlargement was not dependent on host density, basal area, or gap-maker diameter, and tended to stabilize over time, probably because of fungal competition in root wood and lack of sufficient suitable host material along gap margins.

Implementation constraints limit benefits of restoration treatments in mixed-conifer forests

2019 ◽  
Vol 28 (7) ◽  
pp. 495 ◽  
Author(s):  
Jamie M. Lydersen ◽  
Brandon M. Collins ◽  
Carolyn T. Hunsaker
Keyword(s):  
Sierra Nevada ◽  
Forest Structure ◽  
Forest Restoration ◽  
Tree Mortality ◽  
Canopy Cover ◽  
Basal Area ◽  
Severe Drought ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Trade Offs

Forest restoration treatments seek to increase resilience to wildfire and a changing climate while avoiding negative impacts to the ecosystem. The extent and intensity of treatments are often constrained by operational considerations and concerns over uncertainty in the trade-offs of addressing different management goals. The recent (2012–15) extreme drought in California, USA, resulted in widespread tree mortality, particularly in the southern Sierra Nevada, and provided an opportunity to assess the effects of restoration treatments on forest resilience to drought. We assessed changes in mixed-conifer forest structure following thinning and understorey burning at the Kings River Experimental Watersheds in the southern Sierra Nevada, and how treatments, topography and forest structure related to tree mortality in the recent drought. Treatments had negligible effect on basal area, tree density and canopy cover. Following the recent drought, average basal area mortality within the watersheds ranged from 5 to 26% across riparian areas and 12 to 44% across upland areas, with a range of 0 to 95% across all plots. Tree mortality was not significantly influenced by restoration treatments or topography. Our results suggest that the constraints common to many restoration treatments may limit their ability to mitigate the impacts of severe drought.

scholarly journals Trends in Snag Populations in Drought-Stressed Mixed-Conifer and Ponderosa Pine Forests (1997–2007)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Joseph L. Ganey ◽  
Scott C. Vojta
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Management Practices ◽  
Pine Forests ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Ecological Processes ◽  
Ponderosa Pine Forests ◽  
Class Composition

Snags provide important biological legacies, resources for numerous species of native wildlife, and contribute to decay dynamics and ecological processes in forested ecosystems. We monitored trends in snag populations from 1997 to 2007 in drought-stressed mixed-conifer and ponderosa pine (Pinus ponderosaDougl.exLaws) forests, northern Arizona. Median snag density increased by 75 and 90% in mixed-conifer and ponderosa pine forests, respectively, over this time period. Increased snag density was driven primarily by a large pulse in drought-mediated tree mortality from 2002 to 2007, following a smaller pulse from 1997 to 2002. Decay-class composition and size-class composition of snag populations changed in both forest types, and species composition changed in mixed-conifer forest. Increases in snag abundance may benefit some species of native wildlife in the short-term by providing increased foraging and nesting resources, but these increases may be unsustainable in the long term. Observed changes in snag recruitment and fall rates during the study illustrate the difficulty involved in modeling dynamics of those populations in an era of climate change and changing land management practices.

Stand, species, and tree dynamics of an uneven-aged, mixed conifer forest type

1995 ◽  
Vol 25 (5) ◽  
pp. 803-812 ◽  
Author(s):  
John P. McTague ◽  
William F. Stansfield
Keyword(s):  
Tree Mortality ◽  
Forest Type ◽  
Species Abundance ◽  
Basal Area ◽  
Logistic Function ◽  
Conifer Forest ◽  
Individual Tree ◽  
Recovery Method ◽  
Parameter Recovery ◽  
Tree Survival

Stand-level equations are presented that project future merchantable tree survival, pole-tree basal area, and sawtimber basal area. Total basal area (excluding ingrowth) is the sum of the pole-tree and sawtimber components. Ratio equations are used for eight species (seven softwoods and one hardwood) to compute the change in species abundance and species basal area over time. Individual-tree mortality is predicted with a logistic function, while individual-tree diameter growth is predicted as a function of stand and individual-tree attributes. The individual-tree and species-level equations are adjusted so that tree frequency and basal area are consistent with the stand-level projection equations. Total ingrowth is computed with a stand-level projection equation and is distributed with a parameter recovery method using the uniform distribution. The presence or absence of ingrowth for a given species is determined with a discriminant function, while the proportion of total ingrowth allocated to a species is predicted with a logistic function.

Etiology of canopy gaps in spruce–fir forests at Crawford Notch, New Hampshire

1988 ◽  
Vol 18 (11) ◽  
pp. 1463-1469 ◽  
Author(s):  
J. J. Worrall ◽  
T. C. Harrington
Keyword(s):  
Forest Canopy ◽  
Forest Type ◽  
Basal Area ◽  
Natural Disturbance ◽  
Ground Level ◽  
Canopy Gaps ◽  
Relative Importance ◽  
Conifer Forest ◽  
Canopy Trees ◽  
Spruce Beetle

Natural disturbance agents causing formation of canopy gaps were identified and quantified at five elevations (640, 765, 885, 1005, and 1130 m) in an old-growth spruce–fir forest. Actual and expanded gaps were measured to the inner edge of the crown or to the bole, respectively, of the live canopy trees at the gap margin. The percentage of forest canopy in gaps was lowest (6% for actual and 40% for expanded gap areas) at 1005 m elevation, near the upper limit of the spruce–fir phase, and highest (33% actual and 77% expanded) where the spruce–fir phase meets the mixed hardwood–conifer forest type at 765 m elevation. Mean gap size was smallest at the higher elevations. Expanded gap area was apportioned to tree species and disturbance agents according to basal area of affected trees in each gap. Twenty-two identified agents were involved in gap-phase mortality, and their relative importance varied strongly with elevation. Biotic diseases accounted for 66% of gap area at the lowest elevation (640 m) and only 7 and 15%, respectively, at the highest elevations (1005 and 1130 m). Root and butt rots were the most important group of biotic diseases at all elevations; their primary effect was to predispose trees to breakage of the stem near ground level. In contrast to biotic disease agents, chronic wind stress increased greatly in relative importance with elevation, accounting for 72% of gap area at 1130 m. The spruce beetle was an important disturbance agent at 640 and 765 m, where large, overmature red spruce trees had dominated the stand. Gap etiology appeared to be rarely restricted in time to a single event, and was often complex, with multiple agents occurring in the same gap and on the same tree.

Comparison of burn severity assessments using Differenced Normalized Burn Ratio and ground data

2005 ◽  
Vol 14 (2) ◽  
pp. 189 ◽  
Author(s):  
Allison E. Cocke ◽  
Peter Z. Fulé ◽  
Joseph E. Crouse
Keyword(s):  
Pinus Ponderosa ◽  
Forest Structure ◽  
Tree Mortality ◽  
Fire Severity ◽  
Basal Area ◽  
Burn Severity ◽  
Burned Areas ◽  
Differenced Normalized Burn Ratio ◽  
Severity Levels ◽  
Normalized Burn Ratio

Burn severity can be mapped using satellite data to detect changes in forest structure and moisture content caused by fires. The 2001 Leroux fire on the Coconino National Forest, Arizona, burned over 18 pre-existing permanent 0.1 ha plots. Plots were re-measured following the fire. Landsat 7 ETM+ imagery and the Differenced Normalized Burn Ratio (ΔNBR) were used to map the fire into four severity levels immediately following the fire (July 2001) and 1 year after the fire (June 2002). Ninety-two Composite Burn Index (CBI) plots were compared to the fire severity maps. Pre- and post-fire plot measurements were also analysed according to their imagery classification. Ground measurements demonstrated differences in forest structure. Areas that were classified as severely burned on the imagery were predominantly Pinus ponderosa stands. Tree density and basal area, snag density and fine fuel accumulation were associated with severity levels. Tree mortality was not greatest in severely burned areas, indicating that the ΔNBR is comprehensive in rating burn severity by incorporating multiple forest strata. While the ΔNBR was less accurate at mapping perimeters, the method was reliable for mapping severely burned areas that may need immediate or long-term post-fire recovery.

scholarly journals New Taxon-Specific Heterobasidion PCR Primers Detect and Differentiate North American Heterobasidion spp. in Various Substrates and Led to the Discovery of Heterobasidion irregulare in British Columbia, Canada

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 156
Author(s):  
Simon Francis Shamoun ◽  
Craig Hammett ◽  
Grace Sumampong ◽  
Xiang Li ◽  
Matteo Garbelotto
Keyword(s):  
British Columbia ◽  
Pinus Ponderosa ◽  
North American ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Wood Decay ◽  
Wood Products ◽  
White Rot ◽  
Heterobasidion Annosum ◽  
New Taxon

Heterobasidion annosum sensu lato is a species complex of pathogenic white-rot wood decay fungi which cause root and butt rot in conifer and hardwood species across the Northern hemisphere. Annual losses to forest managers are valued in the billions of dollars, due to tree mortality, reduction in timber yield, and wood decay. In North America, H. irregulare and H. occidentale have a partially overlapping host and geographic range, cause similar disease symptoms and produce similar fruiting bodies, making discrimination between the two of them often difficult. We developed two sets of primers that bind specifically to conserved, but species-specific portions of glyceraldehyde 3-phosphate dehydrogenase and elongation factor 1α alleles. The method is sensitive enough to detect either species from infected wood. Analysis of North American isolates has further clarified the distribution of both species on this continent, including the detection of H. irregulare for the first time on ponderosa pine (Pinus ponderosa) and eastern white pine (Pinus strobus) in British Columbia. This method has the potential to be a valuable tool for the detection of the pathogen in exported/imported wood products, as well as for the further identification and assessment of the distribution of North American Heterobasidion species.

Development of the mixed conifer forest in northern New Mexico and its relationship to Holocene environmental change

2008 ◽  
Vol 69 (2) ◽  
pp. 263-275 ◽  
Author(s):  
R. Scott Anderson ◽  
Renata B. Jass ◽  
Jaime L. Toney ◽  
Craig D. Allen ◽  
Luz M. Cisneros-Dozal ◽  
...  
Keyword(s):  
New Mexico ◽  
Pinus Ponderosa ◽  
Late Glacial ◽  
Conifer Forest ◽  
Lake Levels ◽  
Mixed Conifer ◽  
The Holocene ◽  
Groundwater Levels ◽  
Mixed Conifer Forest ◽  
Jemez Mountains

Chihuahueños Bog (2925 m) in the Jemez Mountains of northern New Mexico contains one of the few records of late-glacial and postglacial development of the mixed conifer forest in southwestern North America. The Chihuahueños Bog record extends to over 15,000 cal yr BP. AnArtemisiasteppe, then an openPiceawoodland grew around a small pond until ca. 11,700 cal yr BP whenPinus ponderosabecame established. C/N ratios,δ13C andδ15N values indicate both terrestrial and aquatic organic matter was incorporated into the sediment. Higher percentages of aquatic algae and elevated C/N ratios indicate higher lake levels at the opening of the Holocene, but a wetland developed subsequently as climate warmed. From ca. 8500 to 6400 cal yr BP the pond desiccated in what must have been the driest period of the Holocene there. C/N ratios declined to their lowest Holocene levels, indicating intense decomposition in the sediment. Wetter conditions returned after 6400 cal yr BP, with conversion of the site to a sedge bog as groundwater levels rose. Higher charcoal influx rates after 6400 cal yr BP probably result from greater biomass production rates. Only minor shifts in the overstory species occurred during the Holocene, suggesting that mixed conifer forest dominated throughout the record.

scholarly journals Opportunities for winter prescribed burning in mixed conifer plantations of the Sierra Nevada

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Robert A. York ◽  
Jacob Levine ◽  
Kane Russell ◽  
Joseph Restaino
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Prescribed Burning ◽  
Winter Season ◽  
Basal Area ◽  
Weather Conditions ◽  
Shrub Cover ◽  
Mixed Conifer ◽  
Planted Forests ◽  
Conifer Plantations

Abstract Background Young, planted forests are particularly vulnerable to wildfire. High severity effects in planted forests translate to the loss of previous reforestation investments and the loss of future ecosystem service gains. We conducted prescribed burns in three ~35-year-old mixed conifer plantations that had previously been masticated and thinned during February in order to demonstrate the effectiveness of winter burning, which is not common in the Sierra Nevada, California. Results On average, 59% of fine fuels were consumed and the fires reduced shrub cover by 94%. The average percent of crown volume that was damaged was 25%, with no mortality observed in overstory trees 1 year following the fires. A plot level analysis of the factors of fire effects did not find strong predictors of fuel consumption. Shrub cover was reduced dramatically, regardless of the specific structure that existed in plots. We found a positive relationship between crown damage and the two variables of Pinus ponderosa relative basal area and shrub cover. But these were not particularly strong predictors. An analysis of the weather conditions that have occurred at this site over the past 20 years indicated that there have consistently been opportunities to conduct winter burns. On average, 12 days per winter were feasible for burning using our criteria. Windows of time are short, typically 1 or 2 days, and may occur at any time during the winter season. Conclusions This study demonstrates that winter burning can be an important piece of broader strategies to reduce wildfire severity in the Sierra Nevada. Preparing forest structures so that they can be more feasible to burn and also preparing burn programs so that they can be nimble enough to burn opportunistically during short windows are key strategies. Both small landowners and large agencies may be able to explore winter burning opportunities to reduce wildfire severity.

Clinal differentiation and putative hybridization in a contact zone of Pinus ponderosa and P. arizonica (Pinaceae)

2001 ◽  
Vol 88 (6) ◽  
pp. 1052-1057 ◽  
Author(s):  
Bryan K. Epperson ◽  
Frank W. Telewski ◽  
Anne E. Plovanich-Jones ◽  
Jill E. Grimes
Keyword(s):  
Contact Zone ◽  
Pinus Ponderosa

scholarly journals Verbenone Inhibits Attraction of Ips pini (Coleoptera: Curculionidae) to Pheromone-Baited Traps in Northern Arizona

2020 ◽  
Vol 113 (6) ◽  
pp. 3017-3020
Author(s):  
Monica L Gaylord ◽  
Stephen R McKelvey ◽  
Christopher J Fettig ◽  
Joel D McMillin
Keyword(s):  
Aggregation Pheromone ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Treatment Options ◽  
Current Treatment ◽  
Northern Arizona ◽  
Pine Engraver ◽  
Baited Traps ◽  
Significant Difference

Abstract Recent outbreaks of engraver beetles, Ips spp. De Geer (Coleoptera: Curculionidae; Scolytinae), in ponderosa pine, Pinus ponderosa var. scopulorum Engelm. (Pinales: Pinaceae), forests of northern Arizona have resulted in widespread tree mortality. Current treatment options, such as spraying individual P. ponderosa with insecticides or deep watering of P. ponderosa in urban and periurban settings, are limited in applicability and scale. Thinning stands to increase tree vigor is also recommended, but appropriate timing is crucial. Antiaggregation pheromones, widely used to protect high-value trees or areas against attacks by several species of Dendroctonus Erichson (Coleoptera: Curculionidae; Scolytinae), would provide a feasible alternative with less environmental impacts than current treatments. We evaluated the efficacy of the antiaggregation pheromone verbenone (4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-one) in reducing attraction of pine engraver, I. pini (Say), to funnel traps baited with their aggregation pheromone in two trapping assays. Treatments included 1) unbaited control, 2) aggregation pheromone (bait), 3) bait with verbenone deployed from a pouch, and 4) bait with verbenone deployed from a flowable and biodegradable formulation (SPLAT Verb, ISCA Technologies Inc., Riverside, CA). Unbaited traps caught no beetles. In both assays, baited traps caught significantly more I. pini than traps with either formulation of verbenone, and no significant difference was observed between the verbenone pouch and SPLAT Verb. In the second assay, we also examined responses of Temnochila chlorodia (Mannerheim) (Coleoptera: Trogositidae), a common bark beetle predator. Traps containing verbenone pouches caught significantly fewer T. chlorodia than the baited control and SPLAT Verb treatments. We conclude that verbenone shows promise for reducing tree mortality from I. pini.

Sign in / Sign up

Export Citation Format

Share Document