Heterogeneity in ponderosa pine/Douglas-fir forests: age and size structure in unlogged and logged landscapes of central Colorado

2000 ◽  
Vol 30 (5) ◽  
pp. 698-711 ◽  
Author(s):  
Merrill R Kaufmann ◽  
Claudia M Regan ◽  
Peter M Brown
Keyword(s):  
Ponderosa Pine ◽  
Size Structure ◽  
Fire Regime ◽  
Age Distribution ◽  
Landscape Scale ◽  
Tree Density ◽  
Tree Age ◽  
Riparian Areas ◽  
Forest Patches ◽  
Tree Removal

Tree age and size structures were compared within and among topographic categories in portions of a 35-km2 unlogged landscape and a comparable adjacent logged landscape. Tree density was generally higher in the logged landscape. One fifth of plots in the unlogged landscape had trees older than 400 years, but no trees older than 400 years remained in the logged landscape plots. Ten recruitment pulses were identified for the unlogged study area, accounting for 49% of all trees measured during 26% of the 421-year survival record. Recruitment pulses in the logged area accounted for fewer trees during a larger amount of time. Most recruitment periods in the unlogged landscape coincided with known past major fires. The mixed-severity historical fire regime created openings that persisted for as long as 148 years. The following components exist in the unlogged landscape: (i) forest patches having a distinct age cap reflecting regeneration following an earlier stand-replacing fire, (ii) uneven-aged forest patches having no evidence of an age cap, (ii) openings created by fire, and (iv) riparian areas. Results suggest that the logged landscape is poised to regain an old-growth age distribution, and tree removal in the logged landscape could restore the size distribution found in the unlogged landscape. However, the unlogged landscape has openings not found in the logged landscape that should be considered in restoration efforts at a landscape scale.

Fire regime shift linked to increased forest density in a piñon–juniper savanna landscape

2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis
Keyword(s):  
Regime Shift ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Tree Density ◽  
High Severity ◽  
Wide Range ◽  
In Fire

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.

Fire regimes and vegetation sensitivity analysis: an example from Bradshaw Station, monsoonal northern Australia

2003 ◽  
Vol 12 (4) ◽  
pp. 349 ◽  
Author(s):  
Cameron Yates ◽  
Jeremy Russell-Smith
Keyword(s):  
Fire History ◽  
Fire Regime ◽  
Landscape Scale ◽  
Fire Season ◽  
Individual Species ◽  
Northern Australia ◽  
Sensitive Species ◽  
Obligate Seeder ◽  
Return Interval ◽  
Noaa Avhrr

The fire-prone savannas of northern Australia comprise a matrix of mostly fire-resilient vegetation types, with embedded fire-sensitive species and communities particularly in rugged sandstone habitats. This paper addresses the assessment of fire-sensitivity at the landscape scale, drawing on detailed fire history and vegetation data assembled for one large property of 9100�km2, Bradshaw Station in the Top End of the Northern Territory, Australia. We describe (1) the contemporary fire regime for Bradshaw Station for a 10 year period; (2) the distribution and status of 'fire sensitive' vegetation; and (3) an assessment of fire-sensitivity at the landscape scale. Fire-sensitive species (FSS) were defined as obligate seeder species with minimum maturation periods of at least 3 years. The recent fire history for Bradshaw Station was derived from the interpretation of fine resolution Landsat MSS and Landsat TM imagery, supplemented with mapping from coarse resolution NOAA-AVHRR imagery where cloud had obstructed the use of Landsat images late in the fire season (typically October–November). Validation assessments of fire mapping accuracy were conducted in 1998 and 1999. On average 40% of Bradshaw burnt annually with about half of this, 22%, occurring after August (Late Dry Season LDS), and 65% of the property burnt 4 or more times, over the 10 year period; 89% of Bradshaw Station had a minimum fire return interval of less than 3 years in the study period. The derived fire seasonality, frequency and return interval data were assessed with respect to landscape units (landsystems). The largest landsystem, Pinkerton (51%, mostly sandstone) was burnt 41% on average, with about 70% burnt four times or more, over the 10 year period. Assessment of the fire-sensitivity of individual species was undertaken with reference to data assembled for 345 vegetation plots, herbarium records, and an aerial survey of the distribution of the long-lived obligate-seeder tree species Callitris intratropica. A unique list of 1310 plant species was attributed with regenerative characteristics (i.e. habit, perenniality, resprouting capability, time to seed maturation). The great majority of FSS species were restricted to rugged sandstone landforms. The approach has wider application for assessing landscape fire-sensitivity and associated landscape health in savanna landscapes in northern Australia, and elsewhere.

Tree and opening spatial patterns vary by tree density in two old-growth remnant ponderosa pine forests in Northern Arizona, USA

2019 ◽  
Vol 450 ◽  
pp. 117502 ◽  
Author(s):  
Jose M. Iniguez ◽  
James F. Fowler ◽  
W. Keith Moser ◽  
Carolyn H. Sieg ◽  
L. Scott Baggett ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Ponderosa Pine ◽  
Tree Density ◽  
Pine Forests ◽  
Old Growth ◽  
Ponderosa Pine Forests ◽  
Northern Arizona

A comparison of targeted and systematic fire-scar sampling for estimating historical fire frequency in south-western ponderosa pine forests

2013 ◽  
Vol 22 (8) ◽  
pp. 1021 ◽  
Author(s):  
Calvin A. Farris ◽  
Christopher H. Baisan ◽  
Donald A. Falk ◽  
Megan L. Van Horne ◽  
Peter Z. Fulé ◽  
...  
Keyword(s):  
Ponderosa Pine ◽  
Fire History ◽  
Spatial Scales ◽  
Fire Frequency ◽  
Landscape Scale ◽  
Pine Forests ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
Targeted Sampling ◽  
Statistical Measures

Fire history researchers employ various forms of search-based sampling to target specimens that contain visible evidence of well preserved fire scars. Targeted sampling is considered to be the most efficient way to increase the completeness and length of the fire-scar record, but the accuracy of this method for estimating landscape-scale fire frequency parameters compared with probabilistic (i.e. systematic and random) sampling is poorly understood. In this study we compared metrics of temporal and spatial fire occurrence reconstructed independently from targeted and probabilistic fire-scar sampling to identify potential differences in parameter estimation in south-western ponderosa pine forests. Data were analysed for three case studies spanning a broad geographic range of ponderosa pine ecosystems across the US Southwest at multiple spatial scales: Centennial Forest in northern Arizona (100ha); Monument Canyon Research Natural Area (RNA) in central New Mexico (256ha); and Mica Mountain in southern Arizona (2780ha). We found that the percentage of available samples that recorded individual fire years (i.e. fire-scar synchrony) was correlated strongly between targeted and probabilistic datasets at all three study areas (r=0.85, 0.96 and 0.91 respectively). These strong positive correlations resulted predictably in similar estimates of commonly used statistical measures of fire frequency and cumulative area burned, including Mean Fire Return Interval (MFI) and Natural Fire Rotation (NFR). Consistent with theoretical expectations, targeted fire-scar sampling resulted in greater overall sampling efficiency and lower rates of sample attrition. Our findings demonstrate that targeted sampling in these systems can produce accurate estimates of landscape-scale fire frequency parameters relative to intensive probabilistic sampling.

scholarly journals Landscape-scale drivers of mammalian species richness and functional diversity in forest patches within a mixed land-use mosaic

2020 ◽  
Vol 113 ◽  
pp. 106176
Author(s):  
Yvette C. Ehlers Smith ◽  
David A. Ehlers Smith ◽  
Tharmalingam Ramesh ◽  
Colleen T. Downs
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Functional Diversity ◽  
Mammalian Species ◽  
Landscape Scale ◽  
Forest Patches ◽  
Mixed Land Use

Perspectives on the age and distribution of large wood in riparian carbon pools

2002 ◽  
Vol 59 (3) ◽  
pp. 578-585 ◽  
Author(s):  
Richard P Guyette ◽  
William G Cole ◽  
Daniel C Dey ◽  
Rose-Marie Muzika
Keyword(s):  
Woody Debris ◽  
Age Distribution ◽  
Terrestrial Ecosystems ◽  
Large Wood ◽  
Riparian Ecosystems ◽  
Riparian Areas ◽  
Exponential Distributions ◽  
Drainage Patterns ◽  
Order Of Magnitude ◽  
Negative Exponential

Most knowledge of carbon budgets is derived from the productivity and sequestration of carbon in terrestrial and marine ecosystems. Less is known of carbon stored in riparian areas associated with lakes and rivers. Case studies of the age distribution of carbon in aquatic large wood (Clw) from two different landscapes with different drainage patterns were established using tree-ring and 14C dating. Cumulative negative exponential distributions of the age of Clw ranged over periods from 1000 to 9485 years. Large woody debris had mean residence times of 261 years in small oligotrophic lakes and 350–800 years in a stream reach. Large wood can reside for an order of magnitude longer in freshwater–riparian ecosystems than in comparable above-ground terrestrial ecosystems. Although riparian areas make up only a small fraction of most landscapes, they may account for a relatively larger proportion of aged Clw than is stored above ground in terrestrial ecosystems.

An assessment of dead wood patterns and their relationships with biophysical characteristics in two landscapes with different disturbance histories in coastal Oregon, USA

2007 ◽  
Vol 37 (5) ◽  
pp. 940-956 ◽  
Author(s):  
Rebecca S.H. Kennedy ◽  
Thomas A. Spies
Keyword(s):  
Dead Wood ◽  
Structural Type ◽  
Landscape Scale ◽  
Relative Importance ◽  
Riparian Areas ◽  
Wood Volume ◽  
Source Areas ◽  
Topographic Positions ◽  
Vegetation And Climate ◽  
Biophysical Attributes

Understanding the relative importance of landscape history, topography, vegetation, and climate to dead wood patterns is important for assessing pattern–process relationships related to dead wood and associated biodiversity. We sampled dead wood at four topographic positions in two landscapes (1400–2100 km2) that experienced different wildfire and salvage histories in coastal Oregon. Study objectives were to (i) determine whether and how the landscapes differed in dead wood amounts and characteristics and (ii) evaluate relationships between dead wood characteristics and potentially related biophysical variables associated with historical and current vegetation, topography, climate, soils, and ecoregion. Despite differences in history, the two landscapes differed little in total dead wood volume; however, they differed in dead wood volume by structural type, decay class, and source (legacy/nonlegacy). Dead wood varied by topographic position, and topography was of greatest importance compared with other factors. In this mountainous region, upper topographic positions may be source areas for dead wood and riparian areas and streams sinks for dead wood. Climate explained more variance in dead wood in the landscape that burned earlier and was not salvaged. Landscape-scale patterns of dead wood are evident in landscapes with different disturbance histories and despite finer-scale variation in topography, vegetation, and other biophysical attributes.

scholarly journals Comparing selected fire regime condition class (FRCC) and LANDFIRE vegetation model results with tree-ring data

2010 ◽  
Vol 19 (1) ◽  
pp. 1 ◽  
Author(s):  
Tyson L. Swetnam ◽  
Peter M. Brown
Keyword(s):  
Tree Ring ◽  
Ponderosa Pine ◽  
Fire Regime ◽  
Reference Conditions ◽  
Low Frequency ◽  
Fire Regimes ◽  
Vegetation Types ◽  
Tree Ring Data ◽  
Map Data ◽  
Fire Regime Condition Class

Fire Regime Condition Class (FRCC) has been developed as a nationally consistent interagency method in the US to assess degree of departure between historical and current fire regimes and vegetation structural conditions across differing vegetation types. Historical and existing vegetation map data also are being developed for the nationwide LANDFIRE project to aid in FRCC assessments. Here, we compare selected FRCC and LANDFIRE vegetation characteristics derived from simulation modeling with similar characteristics reconstructed from tree-ring data collected from 11 forested sites in Utah. Reconstructed reference conditions based on trees present in 1880 compared with reference conditions modeled by the Vegetation Dynamics Development Tool for individual Biophysical Settings (BpS) used in FRCC and LANDFIRE assessments showed significance relationships for ponderosa pine, aspen, and mixed-conifer BpS but not for spruce–fir, piñon–juniper, or lodgepole pine BpS. LANDFIRE map data were found to be ~58% accurate for BpS and ~60% accurate for existing vegetation types. Results suggest that limited sampling of age-to-size relationships by different species may be needed to help refine reference condition definitions used in FRCC assessments, and that more empirical data are needed to better parameterize FRCC vegetation models in especially low-frequency fire types.

scholarly journals The role of temperature and dispersal in moss-microarthropod community assembly after a catastrophic event

2012 ◽  
Vol 367 (1605) ◽  
pp. 3042-3049 ◽  
Author(s):  
Giselle Perdomo ◽  
Paul Sunnucks ◽  
Ross M. Thompson
Keyword(s):  
Climate Change ◽  
Community Assembly ◽  
Size Structure ◽  
Landscape Scale ◽  
Model Systems ◽  
Habitat Isolation ◽  
Catastrophic Event ◽  
Extreme Climatic Events ◽  
Effects Of Temperature

There is a clear crisis in the maintenance of biodiversity. It has been generated by a multitude of factors, notably habitat loss, now compounded by the effects of climate change. Predicted changes in climate include increased severity and frequency of extreme climatic events. To manage landscapes, an understanding of the processes that allow recovery from these extreme events is required. Understanding these landscape-scale processes of community assembly and disassembly is hindered by the large scales at which they operate. Model systems provide a means of studying landscape scale processes at tractable scales. Here, we assess the combined effects of temperature and habitat-patch isolation on assembly of naturally diverse moss microarthropod communities after a high-temperature event. We show that community assembly depends on temperature and on degree of habitat isolation. Heated communities were heavily dominated in abundance by two species, one of them relatively large. The resulting size-structure is unlike that seen in the field. Community composition in habitat fragments appears also to have been influenced by the source pool of recolonizing fauna. Our results highlight the value of dispersal in disturbed landscapes and the potential for habitat connectivity to buffer communities from the effects of climate change.

Fine root growth and mortality in different-aged ponderosa pine stands

2008 ◽  
Vol 38 (7) ◽  
pp. 1797-1806 ◽  
Author(s):  
Chris P. Andersen ◽  
Donald L. Phillips ◽  
Paul T. Rygiewicz ◽  
Marjorie J. Storm
Keyword(s):  
Root Growth ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Standing Crop ◽  
Fine Root ◽  
Tree Age ◽  
Root Production ◽  
Age Classes ◽  
Old Growth ◽  
Pine Stands

Root minirhizotron tubes were installed at two sites around three different age classes of ponderosa pine ( Pinus ponderosa Dougl. ex Laws.) to follow patterns of fine root (≤2 mm diameter) dynamics during a 4 year study. Both sites were old-growth forests until 1978, when one site was clear-cut and allowed to regenerate naturally. The other site had both intermediate-aged trees (50–60 years) and old-growth trees (>250 years old). Estimates of fine root standing crop were greatest around young trees and least around intermediate-aged trees. Root production was highly synchronized in all age classes, showing a single peak in late May – early June each year. Root production and mortality were proportional to standing root crop (biomass), suggesting that allocation to new root growth was proportional to root density regardless of tree age. The turnover index (mortality/maximum standing crop) varied from 0.62 to 0.89·year–1, indicating root life spans in excess of 1 year. It appears that young ponderosa pine stands have greater rates of fine root production than older stands but lose more fine roots each year through mortality. The results indicate that soil carbon may accumulate faster in younger than in older stands.

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