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

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.

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

International Journal of Wildland Fire ◽

10.1071/wf19067 ◽

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.

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Tree Species Composition and Natural Regeneration Status of Southeast Region of Bangladesh

Journal of Tropical Biodiversity and Biotechnology ◽

10.22146/jtbb.49988 ◽

2020 ◽

Vol 5 (1) ◽

pp. 27

Author(s):

Abir Dey ◽

Aklima Akther

Keyword(s):

Species Composition ◽

Tree Species ◽

Natural Regeneration ◽

Native Species ◽

Basal Area ◽

Conservation Strategies ◽

Stem Density ◽

Importance Value Index ◽

Tree Species Composition ◽

Large Trees

The study aimed to quantify and discuss the current condition of the tree species composition and natural regeneration of southeast parts of Bangladesh (Cox’s Bazar North Forest Division). A total of 121 stems having dbh ≥10cm and 3481 stems of regenerating tree species (dbh <10cm) per hectare were recorded. A large trees comprised of 17 species belonging to 10 families and 14 genera and 30 regenerating tree species belonging to 19 families and 27 genera have been found. The forests were highly non-uniform, with three or four species represented most of the stands. The values of diversity indices indicated limited plant diversity, which is dominated by two or three tree species. Stems of 10-30 cm dbh contributed almost 90% of the total stem density, whereas more than 80% of the total basal area still belonged to trees with dbh 100 cm or above. Dipterocarpus turbinatus was the most dominant species which have the highest Importance Value Index (IVI) with 135.82 and embodied 37.71% of the total stand density and 72.19% of total basal area. The study will provide scientific basis for the future implementation of forest conservation strategies in tropical forests of Southeast Asia, particularly in Bangladesh. This study may also pave the way to further research on regeneration potentials of the native species for conservation and enhancement of forests in future.

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Comparison of thinning and prescribed fire restoration treatments to Sierran mixed-conifer historic conditions

Canadian Journal of Forest Research ◽

10.1139/x06-236 ◽

2007 ◽

Vol 37 (2) ◽

pp. 331-342 ◽

Cited By ~ 106

Author(s):

Malcolm North ◽

Jim Innes ◽

Harold Zald

Keyword(s):

Spatial Pattern ◽

Prescribed Fire ◽

Diameter Distribution ◽

Stem Density ◽

Conifer Forest ◽

Mixed Conifer ◽

Size Classes ◽

Large Tree ◽

Large Trees ◽

Before And After

Thinning and prescribed fire are widely used to restore fire-suppressed forests, yet there are few studies of their effectiveness in Sierran mixed-conifer forest. We compared stand conditions in replicated plots before and after a combination of thinning and burning treatments against a reconstruction of the same forest in 1865. The historical forest had 67 stems/ha (trees ≥5 cm DBH), equal percentages of shade-tolerant and -intolerant tree species, stems randomly distributed at the stand scale, and a flat diameter distribution across size classes. The pretreatment forest averaged 469 stems/ha, which comprised 84% shade-tolerant and 14% shade-intolerant species, were highly clustered, and had a reverse-J-shaped diameter distribution. Thinning treatments failed to approximate historical composition, spatial pattern, or diameter distribution. Treatments left too many small trees, removed too many intermediate-sized trees (50–75 cm DBH), and retained a reverse-J-shaped diameter distribution. Current old growth comprises fewer large trees than historical conditions, suggesting that treatments should retain more intermediate-sized trees to provide for future large-tree recruitment. Understory thinning with prescribed fire significantly reduced stem density and produced a spatial pattern closest to historical conditions. Mixed-conifer restoration needs thinning prescriptions that vary by species and flexible rather than rigid upper diameter limits to retain some trees in all size classes.

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Assessing Forest Structure and Composition along the Altitudinal Gradient in the State of Sikkim, Eastern Himalayas, India

Forests ◽

10.3390/f10080633 ◽

2019 ◽

Vol 10 (8) ◽

pp. 633 ◽

Cited By ~ 3

Author(s):

Yangchenla Bhutia ◽

Ravikanth Gudasalamani ◽

Rengaian Ganesan ◽

Somidh Saha

Keyword(s):

Species Diversity ◽

Forest Structure ◽

Altitudinal Gradient ◽

Large Diameter ◽

Stem Density ◽

Significant Finding ◽

Lower Altitude ◽

Eastern Himalayas ◽

Large Trees ◽

Low Altitude

Understanding the structure and composition of native forests is a prerequisite in developing an adaptive forest management plan for Himalayan forest ecosystems where climate change is rapid. However, basic information on forest structure and composition are still limited in many places of the Eastern Himalayas. In this study, we aimed to understand the diversity, structure, and composition of forests and their variations along an altitudinal gradient in Himalayan forests. The study was conducted in the Indian federal state of Sikkim, Eastern Himalayas. We carried out a comprehensive and comparative evaluation of species diversity, stand basal area, and stem density along the altitudinal gradient from 900m a.s.l.to 3200m a.s.l. We used stratified random sampling to survey eighty-three plots each 0.1 ha in forest communities that occurred along the altitudinal gradient: (a) lower (900–1700 m) altitude forest (N = 24), (b) mid (1700–2500 m) altitude forests (N = 37), and (c) higher (2500–3200 m)altitude forests (N = 22). We measured and identified all living trees with a >3 cm diameter at breast height in each plot. We counted 10,344 individual plants, representing 114 woody species belonging to 42 families and 75 genera. The family Fagaceae and its species Lithocarpus pachyphyllus (Kurz) Rehder. were reported as the most dominant forest trees with the highest Importance Value Index. The Shannon diversity index was recorded as being the highest for the low-altitude forests, whereas measures of structural diversity varied among forests along with altitude: the mid-altitude forests recorded the highest stem density and the high-altitude forests showed the highest mean stem DBH (diameter at 1.3 m height). One significant finding of our study was the disparity of the size class distribution among forests along the altitudinal gradient. Overall, we found a reverse J-shape distribution of tree diameter signifying the uneven-agedness. However, we showed, for the first time, a complete lack of large trees (>93 cm DBH) in the lower altitude forests. Our study highlights conservation concerns for the low-altitude forests that record high species diversity, although lacked large-diameter trees. We anticipate that our study will provide a comprehensive understanding of forest diversity, composition, and structure along the altitudinal gradient to design conservation and sustainable management strategies

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A Density Management Diagram for Longleaf Pine Stands with Application to Red-Cockaded Woodpecker Habitat

Southern Journal of Applied Forestry ◽

10.1093/sjaf/31.1.28 ◽

2007 ◽

Vol 31 (1) ◽

pp. 28-38 ◽

Cited By ~ 24

Author(s):

John D. Shaw ◽

James N. Long

Keyword(s):

Stand Structure ◽

Longleaf Pine ◽

Large Diameter ◽

Basal Area ◽

Pinus Palustris ◽

Stand Density ◽

Geographic Area ◽

Stem Density ◽

Picoides Borealis ◽

Red Cockaded Woodpecker

Abstract We developed a density management diagram (DMD) for longleaf pine (Pinus palustris P. Mill.) using data from Forest Inventory and Analysis plots. Selection criteria were for purity, defined as longleaf pine basal area (BA) that is 90% or more of plot BA, and even-agedness, as defined by a ratio between two calculations of stand density index. The diagram predicts stand top height (mean of tallest 40 trees/ac) and volume (ft3/ac) as a function of quadratic mean diameter and stem density (trees/ac). In this DMD we introduce a “mature stand boundary” that, as a model of stand dynamics, restricts the size–density relationship in large-diameter stands more than the expected self-thinning trajectory. The DMD is unbiased by geographic area and therefore should be applicable throughout the range of longleaf pine. The DMD is intended for use in even-aged stands, but may be used for uneven-aged management where a large-group selection system is used. Use of the diagram is illustrated by development of density management regimes intended to create and maintain stand structure desirable for the endangered red-cockaded woodpecker (Picoides borealis).

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Damage to Residual Trees and Advance Regeneration from Skyline and Forwarder Yarding in Mixed-Conifer Stands of Northeastern Oregon

Western Journal of Applied Forestry ◽

10.1093/wjaf/15.2.101 ◽

2000 ◽

Vol 15 (2) ◽

pp. 101-107 ◽

Cited By ~ 4

Author(s):

Andrew Youngblood

Keyword(s):

Pinus Contorta ◽

Fuel Reduction ◽

Mixed Conifer ◽

Larix Occidentalis ◽

Partial Cutting ◽

Blue Mountains ◽

Engelmann Spruce ◽

Advance Regeneration ◽

Large Trees ◽

Reduction Methods

Abstract Reducing the risk of occurrence of wildfire and outbreaks of insects and diseases through fuel reduction is a priority management objective on federal lands within the Blue Mountains in northeastern Oregon. Optimal methods to achieve desired levels of fuel in mixed conifer stands by mechanical means are as yet unknown. One factor essential in evaluating optimal fuel reduction methods is the damage to residual trees and advance regeneration associated with specific combinations of stand condition, prescription, and harvesting system. Residual stem damage on 12,899 stems was compared after partial cutting and yarding with either skyline or ground-based forwarder in mixed conifer stands of northeastern Oregon. There were 6,092 occurrences of damage on 4,074 stems after yarding; 4.1% of the damaged stems had crushed foliage, 15.4% had a broken terminal leader, 26.5% had broken branches, 28.9% were wrenched, 35.0% had scraped bark, and 38.9% had bole scars. Fir (Abies grandis and A. lasiocarpa) seedlings were more frequently damaged than nonfir (Larix occidentalis, Picea engelmannii, and Pinus contorta) seedlings, and the most frequent damage to fir seedlings occurred in units treated by the forwarder. More damage occurred to residual large trees during yarding than to seedlings. Forwarder yarding resulted in slightly more damage to trees than did skyline yarding. Wrenching was generally consistent between residual seedlings and trees. Scarring occurred more frequently to residual trees than to seedlings. Mean scar area per tree on those actually scarred was generally about 40 cm² on seedlings and 256 cm² on residual trees. Despite slight differences in stand damage, both yarding methods met the silviculture prescription of reducing fuel and protecting large western latch, Engelmann spruce, Douglas-fir, and lodgepole pine stems targeted for retention. This suggests that the decision by resource managers to use one method of yarding over the other should probably be based on considerations such as availability of equipment, costs, and soil impacts. West. J. Appl. For. 15(2):101-107.

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Did early logging or changes in disturbance regimes promote high tree densities in river red gum forests?

Australian Journal of Botany ◽

10.1071/bt16025 ◽

2016 ◽

Vol 64 (6) ◽

pp. 530 ◽

Cited By ~ 7

Author(s):

Hugh W. McGregor ◽

Matthew J. Colloff ◽

Ian D. Lunt

Keyword(s):

Stand Structure ◽

Root Zone ◽

Canopy Cover ◽

Basal Area ◽

Stem Density ◽

Mature Trees ◽

Large Trees ◽

Zone Of Influence ◽

Disturbance Recovery ◽

River Red Gum

Density of woody plants is thought to have increased in many ecosystems in Australia since European colonisation. Globally, there has been much debate as to whether this phenomenon is driven by the process of post-disturbance recovery – whereby historical logging resulted in the replacement of large, mature trees with smaller, younger trees – or by the process of encroachment – whereby cessation of disturbance events reduced the mortality of seedlings and saplings. We examined the extent to which historical changes in forest structure are compatible with each of these models. The study was conducted in river red gum Eucalyptus camaldulensis Dehnh. floodplain forest on the River Murray at Millewa Forest, southern New South Wales. We compared ‘historical’ (~1860s) stand structure to ‘current’ structure in 45 one-hectare quadrants randomly stratified between three forest productivity classes. Historical trees were determined by stumps or stags likely to have been cut during the late 1800s. Size and position of each historical and current tree was recorded, and used to calculate stem density, basal area, canopy cover and the area of the ‘zone of influence’ (the peripheral extent of the root zone). Current stand structure was vastly different from historical structure. Stem density has increased 9-fold, from a mean of 17 (historical) to 147 (current) trees ha–1. However, basal area increased only slightly, from 13.0 to 15.3 m2 ha–1. Canopy cover increased substantially from 22.1 to 33.5% cover, as did zone of influence, from 55 to 81% cover. Evidence for both the post-disturbance recovery and encroachment hypotheses was found. The 9-fold increase in stem density between historical and current stands was attributable largely to the replacement of large trees with small trees, because basal area had increased only slightly (by 18%). However, the increase in basal area was associated with a substantial increase in canopy cover and area of the zone of influence, supporting the encroachment hypothesis. Regardless, the post-disturbance recovery hypothesis accounts for the bulk of changes in this river red gum forest.

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Big trees drive forest structure patterns across a lowland Amazon regrowth gradient

Scientific Reports ◽

10.1038/s41598-021-83030-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tassiana Maylla Fontoura Caron ◽

Victor Juan Ulises Rodriguez Chuma ◽

Alexander Arévalo Sandi ◽

Darren Norris

Keyword(s):

Forest Structure ◽

Natural Regeneration ◽

Basal Area ◽

Significant Decline ◽

Forest Regrowth ◽

Large Trees ◽

Amazonian Forests ◽

Mammal Diversity ◽

Structure Patterns ◽

Plot Type

AbstractDegraded Amazonian forests can take decades to recover and the ecological results of natural regeneration are still uncertain. Here we use field data collected across 15 lowland Amazon smallholder properties to examine the relationships between forest structure, mammal diversity, regrowth type, regrowth age, topography and hydrology. Forest structure was quantified together with mammal diversity in 30 paired regrowth-control plots. Forest regrowth stage was classified into three groups: late second-regrowth, early second-regrowth and abandoned pasture. Basal area in regrowth plots remained less than half that recorded in control plots even after 20–25 years. Although basal area did increase in sequence from pasture, early to late-regrowth plots, there was a significant decline in basal area of late-regrowth control plots associated with a decline in the proportion of large trees. Variation in different forest structure responses was explained by contrasting variables, with the proportion of small trees (DBH < 20 cm) most strongly explained by topography (altitude and slope) whereas the proportion of large trees (DBH > 60 cm) was explained by plot type (control vs. regrowth) and regrowth class. These findings support calls for increased efforts to actively conserve large trees to avoid retrogressive succession around edges of degraded Amazon forests.

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Exploring the Recruitment Dynamics of Sugar Maple and Yellow Birch Saplings into Merchantable Stems Following Harvesting in the Acadian Forest Region of New Brunswick, Canada

Canadian Journal of Forest Research ◽

10.1139/cjfr-2021-0226 ◽

2021 ◽

Author(s):

Alex Noel ◽

Jules Comeau ◽

Salah-Eddine El Adlouni ◽

Gaetan Pelletier ◽

Marie-Andrée Giroux

Keyword(s):

New Brunswick ◽

Sugar Maple ◽

Basal Area ◽

Stem Density ◽

Yellow Birch ◽

Probability Of Occurrence ◽

Silvicultural Treatment ◽

Forest Region ◽

Wide Range ◽

Acadian Forest

The recruitment of saplings in forest stands into merchantable stems is a very complex process, thus making it challenging to understand and predict. The recruitment dynamics in the Acadian Forest Region of New Brunswick are not well known or documented. Our objective was to draw an inference from existing large scale routine forest inventories as to the different dynamics behind the recruitment from the sapling layer into the commercial tree size layer in terms of density and occurrence of sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britt.) following harvesting, by looking at many factors on a wide range of spatial and temporal scales using models. Results suggest that the variation in density and probability of occurrence is best explained by the intensity of silvicultural treatment, by the merchantable stem density in each plot, and by the proportion of merchantable basal area of each group of species. The number of recruits of sugar maple and yellow birch stems tend be higher when time since last treatment increases, when mid to low levels of silvicultural treatment intensity were implemented, and within plots having intermediate levels of merchantable stem density. Lastly, our modeling efforts suggest that the probability of occurrence and density of recruitment of both species tend to increase while its share of merchantable basal area increases.

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Post-Wildfire Logging Hinders Regeneration and Increases Fire Risk

Science ◽

10.1126/science.1122855 ◽

2006 ◽

Vol 311 (5759) ◽

pp. 352-352 ◽

Cited By ~ 191

Author(s):

D. C. Donato ◽

J. B. Fontaine ◽

J. L. Campbell ◽

W. D. Robinson ◽

J. B. Kauffman ◽

...

Keyword(s):

Fire Risk ◽

Fuel Reduction ◽

Short Term ◽

High Severity ◽

Fuel Loads ◽

Conifer Regeneration ◽

Biscuit Fire ◽

Additional Reduction

We present data from a study of early conifer regeneration and fuel loads after the 2002 Biscuit Fire, Oregon, USA, with and without postfire logging. Natural conifer regeneration was abundant after the high-severity fire. Postfire logging reduced median regeneration density by 71%, significantly increased downed woody fuels, and thus increased short-term fire risk. Additional reduction of fuels is necessary for effective mitigation of fire risk. Postfire logging can be counterproductive to the goals of forest regenration and fuel reduction.

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