scholarly journals Impact of logging intensity on stem density, basal area and biodiversity indices five years after logging in a Caspian hardwood forest

2017 ◽  
Vol 63 (No. 4) ◽  
pp. 167-172 ◽  
Author(s):  
Behjou Farshad Keivan ◽  
Mollabashi Omid Ghaffarzadeh
Keyword(s):  
Canopy Cover ◽  
Basal Area ◽  
Diversity Indices ◽  
Stem Density ◽  
Forest Biodiversity ◽  
Northern Iran ◽  
Positive Effects ◽  
Biodiversity Indices ◽  
Harvesting Intensity ◽  
Evenness Indices

The aim of the present study was to analyse the impacts of different logging intensities after five years from logging including non-logged, low (3.4 felled stems per hectare), medium (5.2 felled stems per hectare) and high (7.1 felled stems per hectare) treatments on stem density, basal area, canopy cover, and forest biodiversity indices. The study area was located in northern Iran. Data was collected on a set of 120 circular plots with 5 m radius from both non-logged and logging areas. Stem density, basal area, and percentage of canopy cover were measured. Biodiversity study was done by measuring two diversity indices including Simpson’s and Shannon-Wiener’s, two richness indices including Margalef’s and Menhinick’s and two evenness indices including Pielou’s and Hill’s indices. The results indicated that the treatment with the medium logging intensity was found to cause the highest amount of positive effects on stem density, basal area, and biodiversity indices. It is concluded that harvesting intensity should be limited to a medium level (approximately 5 felled trees per hectare) during each logging operation to improve forest biodiversity indices.

Winter selection of roost sites by ruffed grouse during daytime in mixed nordic-temperate forests, Quebec, Canada

2007 ◽  
Vol 85 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Pierre Blanchette ◽  
Jean-Claude Bourgeois ◽  
Sylvain St-Onge
Keyword(s):  
Canopy Cover ◽  
Basal Area ◽  
Stem Density ◽  
Ruffed Grouse ◽  
Multinomial Models ◽  
Stand Type ◽  
Logistic Regressions ◽  
Roosting Behavior ◽  
Selection Of ◽  
Habitat Variables

We determined the categories of roost sites used by ruffed grouse ( Bonasa umbellus (L., 1766)) during daytime in winter from 245 radiotelemetric locations of 26 adult females. We conducted our study in the Réserve faunique de Portneuf, located in a mixed nordic-temperate softwood–hardwood forest in Quebec, Canada. We evaluated the effects of weather, snow, and habitat variables on the incidence of snow burrowing, tree roosting, and on-snow roosting using mixed multinomial models, ANOVA, and logistic regressions. The best logistic regression model of snow burrowing probability was identified using the Akaike path. The incidence of each category of roost sites was 41.2% tree roosts, 36.3% snow burrows, and 22.4% on-snow roosts. Coniferous canopy closure and depth of fluffy snow were the variables that influenced roosting behavior the most. Probability of snow burrowing increased with compaction depth and decreased with coniferous cover. Probability of tree roosting increased with temperature. On-snow roosts had a denser lateral obstruction than snow burrows, whereas tree roosts had a greater coniferous basal area, stem density, and canopy cover than snow burrows. Stand type also influenced the incidence of each category of roost sites, snow burrows dominating in deciduous stands and tree roosts dominating in mixed and coniferous stands.

scholarly journals Biodiversity and population fluctuations of parasitoids of the white peach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti) (Hemiptera: Diaspididae), in kiwifruit orchards in Northern Iran

2019 ◽  
Vol 12 (1) ◽  
pp. 12-21 ◽  
Author(s):  
A.H. Toorani ◽  
H. Abbasipour ◽  
L. Dehghan-Dehnavi
Keyword(s):  
Species Abundance ◽  
Alpha Diversity ◽  
Diversity Indices ◽  
Population Fluctuations ◽  
Parasitoid Species ◽  
Northern Iran ◽  
Pseudaulacaspis Pentagona ◽  
Species Diversity Indices ◽  
Evenness Indices ◽  
White Peach Scale

Summary The white peach scale, Pseudaulacaspis pentagona Targioni-Tozzetti (Hemiptera: Diaspididae), is one of the most important and destructive polyphagous pests of the Rosaceae family trees. Population fluctuations and biodiversity of the hymenopteran parasitoid species associated with the pest were studied in six kiwi orchards in Iran, during one-year period. Parasitoid species abundance, species diversity indices and evenness indices were calculated. Most of the parasitoid species were dominant or eudominant. Based on the alpha diversity indices, the Najarkola region had high diversity and the Kharatkola region had low diversity. The Paeendasteh region (based on Simpson’s Diversity on Camargo evenness indices) and the Samnakola region (based on the modified Nee, and on Smith and Wilson evenness indices) were less uniform. Among the recorded parasitoids, Encarsia berlesei Howard (Hymenoptera: Aphelinidae), followed by Aphytis proclia Walker (Hymenoptera: Aphelinidae), had the highest population in all orchards.

Effects of residual overstory on aspen development in Minnesota

1999 ◽  
Vol 29 (2) ◽  
pp. 284-289 ◽  
Author(s):  
Ronald D Huffman ◽  
Mary Ann Fajvan ◽  
Petra Bohall Wood
Keyword(s):  
Populus Tremuloides ◽  
Canopy Cover ◽  
Basal Area ◽  
Multiple Regression Model ◽  
Coefficient Of Determination ◽  
Stand Age ◽  
Stem Density ◽  
Stand Development ◽  
Quaking Aspen ◽  
Accurate Representation

The effects of different amounts of residual canopy on stand development of quaking aspen (Populus tremuloides Michx.) were examined in a chronosequence of 32 stands spanning 6-10 years since harvest. Residual canopy covers ranged from 0 to 65%, and residual basal areas ranged from 0 to 14.4 m2/ha. Aspen regeneration densities ranged from 7130 to 43 672 stems/ha. Regeneration stem density was affected primarily by residual canopy cover (R2 = 0.27, P = 0.0001) and secondarily by stand age (R2 = 0.09, P = 0.004). Aspen density decreased significantly with increasing residual canopy cover for 7-year-old and 8-year-old regeneration. Residual canopy cover did not significantly affect aspen density in 9-year-old regeneration (R2 = 0.02, P = 0.579) but was negatively related to total height of 9-year-old codominant aspens (R2 = 0.49, P = 0.002). Canopy cover was a more accurate representation of the amount of shade the regeneration received than the density or basal area of residual trees. However, the low value of the coefficient of determination from a multiple-regression model indicates that considerable variation in stem densities and height was unexplained by residual canopy cover, even though it was the best predictor of the variables measured.

scholarly journals Development of Forest Structure and Leaf Area in Secondary Forests Regenerating on Abandoned Pastures in Central Amazônia

2005 ◽  
Vol 9 (6) ◽  
pp. 1-22 ◽  
Author(s):  
Ted R. Feldpausch ◽  
Susan J. Riha ◽  
Erick C. M. Fernandes ◽  
Elisa V. Wandelli
Keyword(s):  
Leaf Area ◽  
Forest Structure ◽  
Small Diameter ◽  
Canopy Cover ◽  
Basal Area ◽  
Primary Forest ◽  
Stem Density ◽  
Total Biomass ◽  
Area Index ◽  
Slash And Burn

Abstract The area of secondary forest (SF) regenerating from pastures is increasing in the Amazon basin; however, the return of forest and canopy structure following abandonment is not well understood. This study examined the development of leaf area index (LAI), canopy cover, aboveground biomass, stem density, diameter at breast height (DBH), and basal area (BA) by growth form and diameter class for 10 SFs regenerating from abandoned pastures. Biomass accrual was tree dominated, constituting ≥94% of the total measured biomass in all forests abandoned ≥4 to 6 yr. Vine biomass increased with forest age, but its relative contribution to total biomass decreased with time. The forests were dominated by the tree Vismia spp. (>50%). Tree stem density peaked after 6 to 8 yr (10 320 stems per hectare) before declining by 42% in the 12- to 14-yr-old SFs. Small-diameter tree stems in the 1–5-cm size class composed >58% of the total stems for all forests. After 12 to 14 yr, there was no significant leaf area below 150-cm height. Leaf area return (LAI = 3.2 after 12 to 14 yr) relative to biomass was slower than literature-reported recovery following slash-and-burn, where LAI can reach primary forest levels (LAI = 4–6) in 5 yr. After 12 to 14 yr, the colonizing vegetation returned some components of forest structure to values reported for primary forest. Basal area and LAI were 50%–60%, canopy cover and stem density were nearly 100%, and the rapid tree-dominated biomass accrual was 25%–50% of values reported for primary forest. Biomass accumulation may reach an asymptote earlier than expected because of even-aged, monospecific, untiered stand structure. The very slow leaf area accumulation relative to biomass and to reported values for recovery following slash-and-burn indicates a different canopy development pathway that warrants further investigation of causes (e.g., nutrient limitations, competition) and effects on processes such as evapotranspiration and soil water uptake, which would influence long-term recovery rates and have regional implications.

Effects of Long-Term Military Training Traffic on Forest Vegetation in Central Minnesota

1996 ◽  
Vol 13 (4) ◽  
pp. 157-163 ◽  
Author(s):  
Thomas A. Greene ◽  
Thomas J. Nichols
Keyword(s):  
Military Training ◽  
Canopy Cover ◽  
Basal Area ◽  
Fold Increase ◽  
Bare Soil ◽  
Stem Density ◽  
Quaking Aspen ◽  
Area Reduction ◽  
Soil Area

Abstract We studied vegetation on traveled and untraveled loamy sands on military training land in central Minnesota to identify traffic-induced differences in species composition, cover, diversity, growth rates, and tree condition. Long-term military traffic resulted in a 23% reduction in overstory basal area, a 14% reduction in canopy cover, a 43% reduction in overstory stem density, and a 20% reduction in overstory species diversity compared with adjacent untraveled areas. Most of the overstory basal area reduction was accounted for by a 78% reduction in quaking aspen basal area. Crown dieback was not significantly affected by traffic. Midstory tree and shrub density was 70% lower on traveled areas. Herbaceous vegetation was denser and more diverse in traveled areas. Traffic caused a six-fold increase in bare soil area on sloping soils, but had no effect on bare soil area on level sites. Our data suggest that moderate, long-term traffic on loamy sand soils results in a relatively stable system which can be thought of as in equilibrium between traffic, natural regenerative forces, and management activities. We caution managers that quaking aspen may decline under traffic, and remind them of the risk of erosion on traveled slopes. North. J. Appl. For. 13(4): 157-163.

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

2016 ◽  
Vol 64 (6) ◽  
pp. 530 ◽  
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.

scholarly journals Successional age and forest structure in a Costa Rican upper montane Quercus forest

1996 ◽  
Vol 12 (5) ◽  
pp. 681-698 ◽  
Author(s):  
Maarten Kappelle ◽  
Thorwald Geuze ◽  
Miguel E. Leal ◽  
Antoine M. Cleef
Keyword(s):  
Tree Species ◽  
Secondary Forest ◽  
Basal Area ◽  
Diversity Indices ◽  
Costa Rican ◽  
Canopy Height ◽  
Primary Forest ◽  
Stem Density ◽  
Neotropical Forests ◽  
Structural Recovery

ABSTRACTChanges in structure of a Costa Rican upper montane Quercus forest were studied in twelve 0.1 ha plots along a chronosequence including 8- to 20-year-old Early Secondary Forest (ESF), 25- to 32-year-old Late Secondary Forest (LSF) and mature Primary Forest (PF). In 1.2 ha 2854 stems ≥ 3.0 cm dbh belonging to 42 tree species were recorded. Tree species richness per 0.1 ha ranged from 15 to 30. Diversity indices did not change significantly during succession. Stem density did not differ significantly among successional phases, while basal area was significantly higher in PF than in ESF and LSF. Maximum canopy height and basal area increased linearly during the first three decades of recovery. Height and dbh showed a significant, logarithmic regression for all forest phases. A period of 84 y was estimated as the theoretically minimum time needed for structural recovery. The maximum canopy height and basal area recovered two to five times slower in upper montane than in lower montane or lowland Neotropical forests.

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.

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

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.

Tree density, basal area and species diversity in a disturbed dry tropical forest of northern India: implications for conservation

2006 ◽  
Vol 33 (3) ◽  
pp. 256-262 ◽  
Author(s):  
R. SAGAR ◽  
J.S. SINGH
Keyword(s):  
Species Diversity ◽  
Tropical Forest ◽  
Basal Area ◽  
Tree Density ◽  
Dry Forest ◽  
Conservation Strategies ◽  
Stem Density ◽  
Dry Tropical Forest ◽  
Number Of Species ◽  
Northern India

Dry tropical forest communities are among the world's most threatened systems and urgent measures are required to protect and restore them in degraded landscapes. For planning conservation strategies, there is a need to determine the few essential measurable properties, such as number of species and basal area, that best describe the dry forest vegetation and its environment, and to document quantitative relationships among them. This paper examines the relationships between forest basal area and diversity components (number of species and evenness) for a disturbed dry tropical forest of northern India. Data were collected from five sites located in the Vindhyan dry tropical forest of India, selected on the basis of satellite images and field observations to represent the entire range of conditions in terms of canopy cover and disturbance regimes. These sites represented different communities in terms of species composition. The forest was poorer in species richness, and lower in stem density and basal area than wet forests of the tropics. Across sites (communities), the diversity components and tree density were positively related with total tree basal area. Considering basal area as a surrogate of biomass and net production, diversity is found to be positively associated with productivity. A positive relationship between basal area, tree density and species diversity may be an important characteristic of the dry forest, where recurring disturbance does not permit concentration of biomass or stems in only a few strong competitors. However, the relationships of basal area with density, alpha diversity and evenness remain statistically significant only when data from all sites, including the extremely disturbed one, are used in the analysis. In some sites there was a greater coefficient of variation (CV) of basal area than in others, attributed to patchy distribution of stems and resultant blanks. Therefore, to enhance the tree diversity of these forests, the variability in tree basal area must be reduced by regulating local disturbances. Conservation activities, particularly fuelwood plantations near human settlements, deferred grazing and canopy enrichment through multi-species plantations of nursery-raised or wild-collected seedlings of desirable species within the forest patches of low basal area, will be needed to attain restoration goals, but reforestation programmes will have to be made attractive to the forest-dwelling communities.

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