Ecosystem management applications of resource objective wildfires in forests of the Grand Canyon National Park, USA

2020 ◽  
Vol 29 (2) ◽  
pp. 190
Author(s):  
Michael T. Stoddard ◽  
Peter Z. Fulé ◽  
David W. Huffman ◽  
Andrew J. Sánchez Meador ◽  
John Paul Roccaforte
Keyword(s):  
Ponderosa Pine ◽  
Grand Canyon ◽  
Canopy Cover ◽  
Basal Area ◽  
Natural Disturbance ◽  
Forest Types ◽  
Mixed Conifer ◽  
Species Dominance ◽  
Management Objectives ◽  
Large Trees

Forest managers of the western United States are increasingly interested in utilising naturally ignited wildfires to achieve management objectives. Wildfires can accomplish a range of objectives, from maintenance of intact ecological conditions, to ecosystem restoration, to playing vital natural disturbance roles; however, few studies have carefully evaluated long-term effectiveness and outcomes of wildfire applications across multiple forest types. We remeasured monitoring plots more than 10 years after ‘resource objective’ (RO) fires were allowed to burn in three main south-western forest types. Results showed minimal effects and effective maintenance of open conditions in an intact pine-oak site. Higher-severity fire and delayed mortality of larger and older trees contributed to reductions in basal area and canopy cover at the mixed-conifer and spruce-fir sites. Species dominance shifted towards ponderosa pine in both the mixed-conifer and spruce-fir sites. Although fires resulted in 46–68% mortality of smaller trees initially, substantial ingrowth brought tree density to near pre-fire levels in all forest types after 12 years. Overall, the 2003 RO fires were broadly successful at maintaining or creating open and heterogeneous conditions and resulted in fire- and drought-tolerant species composition. These conditions are likely to be resilient to changing climate, at least in the short term. Substantial mortality of large trees and continuing loss of basal area, however, are a concern, given further climate warming.

scholarly journals Adjudicating Perspectives on Forest Structure: How Do Airborne, Terrestrial, and Mobile Lidar-Derived Estimates Compare?

2021 ◽  
Vol 13 (12) ◽  
pp. 2297
Author(s):  
Jonathon J. Donager ◽  
Andrew J. Sánchez Meador ◽  
Ryan C. Blackburn
Keyword(s):  
Ponderosa Pine ◽  
Laser Scanning ◽  
Canopy Cover ◽  
Basal Area ◽  
Tree Height ◽  
Absolute Error ◽  
Forest Monitoring ◽  
Individual Tree ◽  
Structural Configurations ◽  
Individual Trees

Applications of lidar in ecosystem conservation and management continue to expand as technology has rapidly evolved. An accounting of relative accuracy and errors among lidar platforms within a range of forest types and structural configurations was needed. Within a ponderosa pine forest in northern Arizona, we compare vegetation attributes at the tree-, plot-, and stand-scales derived from three lidar platforms: fixed-wing airborne (ALS), fixed-location terrestrial (TLS), and hand-held mobile laser scanning (MLS). We present a methodology to segment individual trees from TLS and MLS datasets, incorporating eigen-value and density metrics to locate trees, then assigning point returns to trees using a graph-theory shortest-path approach. Overall, we found MLS consistently provided more accurate structural metrics at the tree- (e.g., mean absolute error for DBH in cm was 4.8, 5.0, and 9.1 for MLS, TLS and ALS, respectively) and plot-scale (e.g., R2 for field observed and lidar-derived basal area, m2 ha−1, was 0.986, 0.974, and 0.851 for MLS, TLS, and ALS, respectively) as compared to ALS and TLS. While TLS data produced estimates similar to MLS, attributes derived from TLS often underpredicted structural values due to occlusion. Additionally, ALS data provided accurate estimates of tree height for larger trees, yet consistently missed and underpredicted small trees (≤35 cm). MLS produced accurate estimates of canopy cover and landscape metrics up to 50 m from plot center. TLS tended to underpredict both canopy cover and patch metrics with constant bias due to occlusion. Taking full advantage of minimal occlusion effects, MLS data consistently provided the best individual tree and plot-based metrics, with ALS providing the best estimates for volume, biomass, and canopy cover. Overall, we found MLS data logistically simple, quickly acquirable, and accurate for small area inventories, assessments, and monitoring activities. We suggest further work exploring the active use of MLS for forest monitoring and inventory.

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.

The effects of burn entry and burn severity on ponderosa pine and mixed conifer forests in Grand Canyon National Park

2015 ◽  
Vol 24 (4) ◽  
pp. 495 ◽  
Author(s):  
Anna M. Higgins ◽  
Kristen M. Waring ◽  
Andrea E. Thode
Keyword(s):  
Ponderosa Pine ◽  
National Park ◽  
Forest Type ◽  
Grand Canyon ◽  
Burn Severity ◽  
Conifer Forests ◽  
Mixed Conifer ◽  
Grand Canyon National Park ◽  
White Fir ◽  
Mixed Conifer Forests

Over a century of fire exclusion in frequent-fire ponderosa pine and dry mixed conifer forests has resulted in increased tree densities, heavy surface fuel accumulations and an increase in late successional, fire-intolerant trees. Grand Canyon National Park uses prescribed fires and wildfires to reduce fire hazard and restore ecosystem processes. Research is needed to determine post-fire vegetation response thus enabling future forest succession predictions. Our study focussed on the effects of burn entry and burn severity on species composition and regeneration in two forest types: ponderosa pine with white fir encroachment and dry mixed conifer. We found no difference in tree composition and structure in a single, low-severity burn compared with unburned areas in the white fir encroachment forest type. We found no white fir seedlings or saplings in a second-entry, low-severity burn in the white fir encroachment forest type. Second-entry burns were effective in reducing white fir densities in the white fir encroachment forest type. There was significant aspen regeneration following high-severity fire in the dry mixed conifer forest type. This research suggests that repeated entries and an increase in burn severity may be necessary for prescribed fire or wildfire to be effective in meeting management objectives.

Regeneration Methods for Tropical High-forests

1981 ◽  
Vol 8 (2) ◽  
pp. 139-147
Author(s):  
Philip R. O. Kio
Keyword(s):  
Basal Area ◽  
Sampling Technique ◽  
Forest Types ◽  
Ecological Processes ◽  
Growth And Survival ◽  
Silvicultural Treatments ◽  
Living Space ◽  
Large Trees ◽  
The Difference ◽  
Silvicultural Prescriptions

Changes taking place in the natural tropical forests are intricate, and the ecological processes which they entail are only gradually becoming understood. Human interference in these processes frequently leads to unforeseen consequences, silvicultural treatments being apt to be applied long before much is known about the characteristics of the constituent species and the particular successional phases on which treatments have been imposed.Perturbations create gaps of varying sizes. Both regeneration in the gaps and the latter's restoration to a state of equilibrium, depend on their size and the intensity of the disturbance. Deflected successions may occur in sensitive ecosystems whereby progress towards vegetational climax is permanently interrupted. In Africa, the human impact on the natural vegetation has been more severe and for a much longer period than in either the Amazon or in large areas of the Indo-Malaysian rain-forest.Apart from the limitations of existing silvicultural techniques for inducing regeneration and promoting growth, vital management decisions are commonly based on the results of regeneration sampling. But this traditional sampling technique does not make sufficient use of the indications provided by Iiocourt's ‘living space’ theory. However, modified procedures which can easily be undertaken and which assign more appropriate areas of occupation to individual seedlings, saplings, poles, and trees in the stand, provide more realistic estimates of the overall stocking. Though much damage is done to saplings and poles by the felling of large trees, the severity of damage is related more to the number of trees felled than to the basal area or volume removed. However, research into effects of alternative logging regimes (monocyclic versus poly cyclic) is required to resolve, for particular forest types, the issue of appropriate management/silvicultural prescriptions.On the basis of silvicultural research in Nigeria, tentative conclusions have been reached that the growth of a residual stand after exploitation can be accelerated by shelterwood treatments. In particular, climber cutting and opening of the canopy by poisoning are effective treatments in promoting recruitment of saplings and poles from seedlings, and their subsequent growth and survival. Controlled logging can be as effective as a poisoning operation to remove shade-casting, uneconomic emergents, and if substituted for such shelterwood poisoning could reduce the expense of implementing forest treatment.In forest management, account must be taken of differing capacities for growth between different species—especially in response to different silvicultural treatments. Thus in the experiments discussed, heavy poisoning promoted greater increments than selective poisoning, though the difference was not statistically significant.

scholarly journals Twenty years of drought‐mediated change in snag populations in mixed‐conifer and ponderosa pine forests in Northern Arizona

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Joseph L. Ganey ◽  
Jose M. Iniguez ◽  
Scott C. Vojta ◽  
Amy R. Iniguez
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Forest Types ◽  
Mixed Conifer ◽  
Size Classes ◽  
Ponderosa Pine Forests ◽  
Northern Arizona ◽  
Mortality Event ◽  
Over Time

Abstract Background Snags (standing dead trees) are important biological legacies in forest systems, providing numerous resources as well as a record of recent tree mortality. From 1997 to 2017, we monitored snag populations in drought-influenced mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona. Results Snag density increased significantly in both forest types. This increase was driven largely by a pulse in snag recruitment that occurred between 2002 and 2007, following an extreme drought year in 2002, with snag recruitment returning to pre-pulse levels in subsequent time periods. Some later years during the study also were warmer and/or drier than average, but these years were not as extreme as 2002 and did not trigger the same level of snag recruitment. Snag recruitment was not equal across tree species and size classes, resulting in significant changes in species composition and size-class distributions of snag populations in both forest types. Because trees were far more abundant than snags in these forests, the effect of this mortality pulse on tree populations was far smaller than its effect on snag populations. Snag loss rates increased over time during the study, even though many snags were newly recruited. This may reflect the increasing prevalence of white fir snags and/or snags in the smaller size classes, which generally decay faster than snags of other species or larger snags. Thus, although total numbers of snags increased, many of the newly recruited snags may not persist long enough to be valuable as nesting substrates for native wildlife. Conclusions Increases in snag abundance appeared to be due to a short-term tree mortality “event” rather than a longer-term pattern of elevated tree mortality. This mortality event followed a dry and extremely warm year (2002) embedded within a longer-term megadrought. Climate models suggest that years like 2002 may occur with increasing frequency in the southwestern U.S. Such years may result in additional mortality pulses, which in turn may strongly affect trajectories in abundance, structure, and composition of snag populations. Relative effects on tree populations likely will be smaller, but, over time, also could be significant.

Seasonal patterns in the activity and species richness of surface-foraging termites (Isoptera) at paper baits in a tropical Australian savanna

2003 ◽  
Vol 19 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Tracy Dawes-Gromadzki ◽  
Alister Spain
Keyword(s):  
Species Richness ◽  
Canopy Cover ◽  
Soil Surface ◽  
Transitional Period ◽  
Forest Types ◽  
Species Dominance ◽  
Optimal Protocol ◽  
Termite Attack ◽  
Decaying Wood ◽  
Eleven Species

The species present, and the frequencies and intensities of termite attack on 600 paper baits exposed at the soil surface were compared over three seasonal exposures and between two savanna sites of contrasting vegetation structure in northern Australia. Eleven species were recorded, with Microcerotermes nervosus and Schedorhinotermes actuosus comprising 43% and 27% of collections respectively. The most commonly sampled species nest underground or build epigeal mounds and are known to feed on sound and decaying wood. Changes in species dominance occurred between seasons and the two forest types. In both vegetation types, the number of species active and the frequency of attack increased with the duration of bait exposure and decreased in the order: transitional > wet > dry. Bait consumption was greater in the site with higher canopy cover, and did not differ significantly between seasons. No direct relationships were noted between rainfall recorded at the sites and species richness, frequency and intensity of attack on baits. We recommend exposure of paper baits for at least 2 mo during the transitional period as the optimal protocol for sampling at the time of greatest activity and diversity of those species within the guild of wood-feeding species regularly attracted to paper baits.

scholarly journals Practical Field Methods of Estimating Canopy Cover, PAR, and LAI in Michigan Oak and Pine Stands

1999 ◽  
Vol 16 (1) ◽  
pp. 25-32 ◽  
Author(s):  
David S. Buckley ◽  
J. G. Isebrands ◽  
Terry L. Sharik
Keyword(s):  
Canopy Cover ◽  
Basal Area ◽  
Forest Types ◽  
Field Methods ◽  
Area Index ◽  
Active Radiation ◽  
Research Relationships ◽  
Pine Stands ◽  
Practical Field ◽  
Strong Relationships

Abstract With the increased use of variables such as canopy cover, photosynthetically active radiation (PAR) and overstory leaf area index (LAI) in forestry research, relationships between these variables and traditional forestry variables must be defined before recommended levels of these research variables can be achieved by forestry practitioners on the ground. We measured basal area, canopy cover, Ozalid percent full light, PAR, and overstory LAI in thinned and unthinned plots within oak and pine stands with the objectives of: (1) determining the relationships between these variables in two common forest types, (2) investigating the feasibility of using basal area to estimate and achieve recommended levels of canopy cover, PAR, and LAI in the field, and (3) examining the possibility of using direct canopy cover and Ozalid light measurements for estimating PAR and LAI. Very strong relationships (r² > 0.90 and P < 0.0001) were indicated between basal area and canopy cover, PAR, and LAI. Direct canopy cover and Ozalid light measurements were also strongly related to PAR and LAI. It is likely that the even-aged structure of the stands studied contributed to these results. The strength of the relationships between the measures examined suggest that practical variables such as basal area could potentially be used by forestry practitioners to estimate and achieve recommended levels of canopy cover, PAR, and LAI in similar oak and pine stands. The possibility also exists for strong relationships between these variables in other stand types that resemble those studied in terms of overstory structure. North. J. Appl. For. 16(1):25-32.

scholarly journals Environmental Effects and Economics of Mechanized Logging for Fuel Reduction in Northeastern Oregon Mixed-Conifer Stands

2003 ◽  
Vol 18 (4) ◽  
pp. 238-249 ◽  
Author(s):  
J.D. McIver ◽  
P.W. Adams ◽  
J.A. Doyal ◽  
E.S. Drews ◽  
B.R. Hartsough ◽  
...  
Keyword(s):  
Large Diameter ◽  
Basal Area ◽  
Fire Risk ◽  
Soil Disturbance ◽  
Stem Density ◽  
Fuel Reduction ◽  
Mass Reduction ◽  
Mixed Conifer ◽  
Soil Microarthropods ◽  
Large Trees

Abstract Fuel reduction by mechanical thinning and removal was studied in mixed-conifer stands in northeastern Oregon between 1995 and 1997. A single-grip harvester was coupled with either a forwarder or a skyline yarding system, and operational economics, fuel reduction, stand damage, soil disturbance, effects on soil biota and down-woody material were measured in three replicates of paired stands. After logging with the harvester, the two log-extraction systems achieved nearly equivalent fuel reduction with 45.7 and 46.8% mass reduction by the forwarder and skyline system, respectively. Fine-woody fuel increased slightly in all units, but mass of heavy fuels decreased. Most mass reduction in the forest floor occurred in the duff layer with 56 and 49% reduction in forwarder and skyline units, respectively. Reduction in stem density and basal area were similar for the two extraction systems; in forwarder units stem density was reduced by 61.6% and basal area by 55.4%, while in skyline units stem density was reduced by 66.5% and basal area by 51.1%. Of seedlings and trees examined, 32% had noticeable damage after harvest. Damage included bole wounding (38.9% of damaged stems), bark scraping (35.0%), wrenched stems (28.9%), broken branches (26.5%), broken terminal leaders (15.4%), and crushed foliage (4.1%). More damage occurred to residual large trees than to seedlings. Both log-extraction systems met the silvicultural prescription of reducing fuel and protecting residual large-diameter western larch, Engelmann spruce, Douglas-fir, and lodgepole pine. While fuel, stem, and basal area reduction lowered fire risk from a model 10 to a model 8 in all stands, large-woody material for wildlife also changed. Mean log length was lower in harvested units relative to unharvested controls, but this did not decrease occupation of logs by ants or the activities of woodpeckers feeding on them. Of 37 logged hectares, 1.4% (0.5 ha) of the soil area was compacted, mostly in forwarder units, within landings, and within trails close to landings. The percent area with displaced soil varied from 5 to 43% among units and was located within trails or in intertrail areas between the trails. Light displacement of soil resulted in a short-term increase in the abundance of soil microarthropods. The effects of compaction on litter microarthropods was more persistent, with lower numbers in compacted litter a year after harvest. While revenue was similar for forwarder and skyline units ($68 vs. $70/metric ton, respectively), total operational costs were $81/metric ton in the skyline units, compared to $46/metric ton in the forwarder units. These results are discussed in the context of options available to managers for balancing fuel reduction needs with both environmental and economic constraints. West. J. Appl. For. 18(4):238–249.

scholarly journals A note on the ecology and management of old-growth forests in the Montane Cordillera

2003 ◽  
Vol 79 (3) ◽  
pp. 441-454 ◽  
Author(s):  
André Arsenault
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Structural Characteristics ◽  
Coniferous Forest ◽  
Natural Disturbance ◽  
Climatic Conditions ◽  
Forest Types ◽  
Old Growth ◽  
Old Growth Forest ◽  
Old Growth Forests

The Montane Cordillera ecozone that spans British Columbia's central and southern interior and a portion of southwestern Alberta contains the greatest variety of old-growth coniferous forest types in Canada. The diverse climates of this region, which include some of the driest, warmest, wettest, and coldest found in southern continental Canada, have directly contributed to the richness of old forest types. Associated with this range in climatic conditions are radically different natural disturbance regimes that have profoundly influenced the distribution, abundance, and structural characteristics of old-growth forests. Old forests tend to be more abundant and to contain more old-growth-dependent organisms in wetter climates. The high number of old-growth-dependent epiphytic lichens in old inland rainforests is a clear expression of this phenomenon. Conversely, old forests are much less abundant in dry landscapes. These forests, often dominated by Ponderosa pine (Pinus ponderosa P. Laws. ex C. Laws.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), have been subject to more frequent natural disturbances, and have been more profoundly influenced by human activities. Although fewer species appear to be dependent on old growth in dry forests, a number of them require certain old-growth structural attributes for their survival. A better understanding of the ecological characteristics of the old-growth forests of Canada's Montane Cordillera will assist in developing informed land-use decisions. Key words: old-growth forest, Montane Cordillera, natural disturbance, landscape ecology and management

A multi-century history of fire regimes along a transect of mixed-conifer forests in central Oregon, U.S.A.

2019 ◽  
Vol 49 (1) ◽  
pp. 76-86 ◽  
Author(s):  
Emily K. Heyerdahl ◽  
Rachel A. Loehman ◽  
Donald A. Falk
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Fire Severity ◽  
Fire Regimes ◽  
Conifer Forests ◽  
Forest Types ◽  
Mixed Conifer ◽  
High Severity ◽  
Mixed Conifer Forests ◽  
History Of

Dry mixed-conifer forests are widespread in the interior Pacific Northwest, but their historical fire regimes are poorly characterized, in particular the relative mix of low- and high-severity fire. We reconstructed a multi-century history of fire from tree rings in dry mixed-conifer forests in central Oregon. These forests are dominated by ponderosa pine (Pinus ponderosa Lawson & C. Lawson), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and grand fir (Abies grandis (Douglas ex D. Don) Lindl.). Across four, 30-plot grids of ∼800 ha covering a mosaic of dry mixed-conifer forest types, we sampled 4065 trees for evidence of both high- and low-severity fire. From 1650 to ∼1900, all four sites sustained frequent, often extensive, low-severity fires that sometimes included small patches of severe fire (50–150 ha during 18%–28% of fire years). Fire intervals were similar among sites and also among forest types within sites (mean intervals of 14–32 years). To characterize the continuous nature of the variation in fire severity, we computed a plot-based index that captures the relative occurrence of low- and high-severity fire. Our work contributes to the growing understanding of variation in past fire regimes in the complex and dynamic forests of North America’s Interior West.

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