scholarly journals Quantitative and qualitative effects of a severe ice storm on an old-growth beech–maple forest

2007 ◽  
Vol 37 (3) ◽  
pp. 598-606 ◽  
Author(s):  
Koichi Takahashi ◽  
Ken Arii ◽  
Martin J. Lechowicz
Keyword(s):  
Detrended Correspondence Analysis ◽  
Basal Area ◽  
Forest Composition ◽  
Permanent Plots ◽  
Stem Density ◽  
Ice Storm ◽  
Eastern Canada ◽  
Old Growth ◽  
The Impact ◽  
Stand Basal Area

Comparing permanent plots censused in 1997 and again in 2005, we quantified the impact of a severe ice storm on forest composition and dynamics in an old-growth beech–maple forest in eastern Canada. Acer saccharum Marsh. and Fagus grandifolia Ehrh. accounted for 78% of stand basal area immediately before the January 1998 ice storm. By 2005, eight growing seasons after the ice storm, stand basal area had dropped from 49.1 m2/ha to 31.5 m2/ha, and total tree density (>1 cm diameter at breast height (DBH)) decreased from 6350 stems/ha to 3875 stems/ha. However, A. saccharum and F. grandifolia remained dominant, accounting for 74% of stand basal area. Detrended correspondence analysis of relative dominance ratios at each plot in 1997 and 2005 showed that community composition did not change much during this period for either understory (1 cm ≤ DBH < 10 cm) or canopy trees (DBH ≥ 10 cm). The ice storm did not lead to significant recruitment of saplings (DBH ≥ 1 cm), but appears to have only contributed more to the growth of already-established saplings. We conclude that the ice storm of 1998 substantially decreased stand basal area and stem density but did not act to change the overall species composition or tree diversity in this old-growth beech–maple forest.

scholarly journals Using survival analysis to predict the harvesting of forest stands in Quebec, Canada

2017 ◽  
Vol 47 (8) ◽  
pp. 1066-1074 ◽  
Author(s):  
L.C. Melo ◽  
R. Schneider ◽  
R. Manso ◽  
J.-P. Saucier ◽  
M. Fortin
Keyword(s):  
Survival Analysis ◽  
Random Effect ◽  
Basal Area ◽  
Permanent Plots ◽  
Stem Density ◽  
Time Varying ◽  
Spatial Correlations ◽  
Explanatory Variables ◽  
Interval Censored ◽  
Level Model

Survival analysis methods make better use of temporal information, accommodate multiple levels of explanatory variables, and are meant to deal with interval-censored data. In a context of harvest modeling, this approach could improve some known limitations. In this study, we used data from a network of permanent plots in the province of Quebec, Canada, as a real-world case study. We tested the potential of survival analysis to predict plot-level harvest probabilities from plot- and regional-level variables. The approach also included random effects to account for spatial correlations. The results showed the potential of survival analysis to provide annual predictions of harvest occurrence. Both regional and time-varying variables, as well as spatial patterns, had important effects on the probability of a plot to be harvested. Respectively, reductions in the annual allowable cut volumes led to a decrease in the harvest probabilities. Greater harvest probabilities were associated with the broadleaved dynamics class and higher values of basal area. In contrast, they were decreased by stem density and slope classes. The spatial random effect resulted in an improvement of the model fit. Our plot-level model improved some limitations reported in previous studies by taking the effect of a time-varying regional variable into account.

Tree vigor and stand growth of Douglas-fir as influenced by laminated root rot

1985 ◽  
Vol 15 (5) ◽  
pp. 985-988 ◽  
Author(s):  
Ram Oren ◽  
Walter G. Thies ◽  
Richard H. Waring
Keyword(s):  
Leaf Area ◽  
Root Rot ◽  
Basal Area ◽  
Douglas Fir ◽  
Basal Area Increment ◽  
Sapwood Area ◽  
Stand Growth ◽  
Area Growth ◽  
The Impact ◽  
Stand Basal Area

Total stand sapwood basal area, a measure of competing canopy leaf area, was reduced 30% by laminated root rot induced by Phellinusweirii (Murr.) Gilb. in a heavily infected 40-year-old coastal stand of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) compared with that of a similar uninfected stand. Annual basal area increment per unit of sapwood area, an index of tree vigor, was expected to increase in uninfected trees in the infected stand as surrounding trees died from root rot; vigor of the uninfected trees did increase by an average of 30%, offsetting the reduction in canopy leaf area. This increase, although less than might be expected in an evenly spaced thinned stand, was sufficient to maintain stand basal area growth at levels similar to those of unthinned forests. These findings indicate that increased growth by residual trees must be taken into account when the impact of disease-induced mortality on stand production is assessed.

The influence of forest composition and climate on outbreak characteristics of the spruce budworm in eastern Canada

2013 ◽  
Vol 43 (12) ◽  
pp. 1181-1195 ◽  
Author(s):  
David R. Gray
Keyword(s):  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Basal Area ◽  
Spruce Budworm ◽  
Climate Scenario ◽  
Forest Composition ◽  
Eastern Canada ◽  
The North ◽  
Average Change ◽  
Maximum Temperatures

The spruce budworm (Choristoneura fumiferana Clemens) is perhaps the single most important disturbance agent in Canada’s eastern forests. Climate and forest composition are dominant factors in spruce budworm outbreak dynamics through their direct influences on the pest, its natural enemies, and its hosts, and through their influence on the multitrophic interactions that are important in outbreak dynamics. A combination of four climate variables, three forest composition variables, and one location variable explained 60% of the multivariate variability in outbreak characteristics (duration and severity) in eastern Canada. Outbreak duration was most strongly influenced by April–May accumulation of degree-days; outbreak severity was most strongly influenced by the extreme maximum temperatures of April–May. The basal area of balsam fir had a stronger influence than that of black spruce on duration and on severity. Both outbreak characteristics declined in more northerly locations. Under a projected future (2011–2040) climate scenario the largest increases in outbreak duration and severity are predicted to occur on the Gaspé Peninsula and the north shore of the St. Lawrence River (Quebec). The largest decreases in duration and severity are predicted to occur in southern Ontario and along the Bay of Fundy in New Brunswick and Nova Scotia. The predicted average change in outbreak duration is around –1.3 years. The predicted average change in outbreak severity is only slightly different from zero (around –1.5% defoliation).

scholarly journals The long-term dynamics of the old-growth structure in the National Nature Reserve Badínsky prales

2020 ◽  
Vol 66 (No. 12) ◽  
pp. 501-510
Author(s):  
Ladislav Šumichrast ◽  
Jaroslav Vencurik ◽  
Ján Pittner ◽  
Stanislav Kucbel
Keyword(s):  
Species Composition ◽  
Relative Density ◽  
Detrended Correspondence Analysis ◽  
Basal Area ◽  
Importance Value ◽  
Old Growth ◽  
Stand Volume ◽  
Structure Dynamics ◽  
Old Growth Forest

The main goal of this paper was to evaluate structure dynamics in the fir-beech, old-growth forest Badínsky prales. Measurements were taken on four permanent research plots (0.5 ha each) between 1970 and 2018, typically in ten-year intervals. In order to assess long-term structure dynamics, this study used basic stand characteristics and selected structural indices – the relative density (RD), coefficient of homogeneity (H), and structural complexity index (SCI). Species composition was quantified by the relative importance value (RIV), and a detrended correspondence analysis was carried out for the visualisation of long-term changes. The long-term mean of the stand volume reached 634 ± 99 m3·ha−1, and the mean of the basal area was 36.6 ± 4.0 m2·ha–1. Calculated values of the coefficient of homogeneity (1.46–2.54) were similar to values in other old-growth forests with a comparable tree species composition. An increasing trend in beech RIV values was observed; on the other hand, fir RIV values fell by approximately 20%–25%. In 2018, maximal values of the basal area, stand volume and relative density were recorded. These high values may indicate better growth conditions due to climate change, as well as fewer disturbance events in the last few decades.

Liana density declined and basal area increased over 12 y in a subtropical montane forest in Argentina

2017 ◽  
Vol 33 (4) ◽  
pp. 241-248 ◽  
Author(s):  
Sergio Javier Ceballos ◽  
Agustina Malizia
Keyword(s):  
Light Availability ◽  
Basal Area ◽  
Anthropogenic Disturbances ◽  
Montane Forest ◽  
Forest Recovery ◽  
Permanent Plots ◽  
Stem Density ◽  
Mature Forest ◽  
Shade Tolerant Species ◽  
North Western

Abstract:Changes in density and basal area of lianas ≥2 cm diameter were monitored in two 1-ha permanent plots in a subtropical montane mature forest of north-western Argentina. Liana stems were identified and measured at 130 cm from the main rooting point in two censuses conducted in 2003 and 2015. Between censuses, the density of liana stems decreased 13.3%, while basal area increased 11.5%. Density and basal area decreased mainly among lianas of 2–3 cm diameter, but increased in lianas ≥4 cm diameter. Quechualia fulta (Asteraceae), Serjania meridionalis (Sapindaceae) and Chamissoa altissima (Amaranthaceae) suffered large reductions in stem density and basal area. Dissimilar responses of density and basal area of lianas might be a consequence of the suppression of anthropogenic disturbances (e.g. livestock browsing) and the decrease of treefall gap frequency in the studied forest in recent decades. Light-demanding liana species decreased and shade-tolerant species increased possibly in response to the decline in the light availability associated with forest recovery from past disturbance. Lianas increased in basal area to a lesser extent compared with reports from several tropical and subtropical forests where lianas are increasing dramatically.

scholarly journals Fuelwood Harvest and No Harvest Effects on Forest Composition, Structure, and Diversity of Arasbaran Forests—A Case Study

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1631
Author(s):  
Sajad Ghanbari ◽  
Christel C. Kern
Keyword(s):  
Species Diversity ◽  
Tree Height ◽  
Woody Species ◽  
Forest Composition ◽  
Stem Density ◽  
Regeneration Status ◽  
Composition And Structure ◽  
Composition Structure ◽  
The Impact

The impact of fuelwood harvesting on forest structure and composition is not clear, especially on the understudied and scarce Arasbaran forests in Iran. This research compared woody species density, species diversity, forest composition, and regeneration status in areas of continuous and ceased fuelwood harvesting in Arasbaran forests. We expected fuelwood harvesting to decrease stem density, species diversity, tree size (diameter at the breast height (DBH) and height), and shift composition away from preferred fuelwood species. We measured woody species size and frequency and identified species in three fuelwood harvest and three no harvest sites, with six sample plots (100 m × 50 m) per site. Results tended to show differences in composition, diversity, woody species height, and density. Carpinus orientalis, a preferred fuelwood species, tended to be more dominant in no harvest (importance values index (IVI) = 173.4) than harvest areas (IVI = 4.4). The diversity or richness of woody species tended to be higher in harvest (20 ± 1 species per ha) than in no harvest (14 ± 2 species per ha) areas, and other measures of diversity supported this trend as well. Harvest areas tended to also be characterized by shorter tree height and lower density of trees, a higher density of regeneration, and fewer small pole-sized trees than no harvest areas. Ongoing fuelwood harvests may further shift composition and structure away from no harvest area, compromising future fuelwood availability, but further detailed research is needed. Close to nature practices may be useful in sustaining fuelwood harvest areas and diversifying areas where fuelwood harvesting has ceased.

scholarly journals Evaluating the current ecological status and proposing rehabilitation interventions for the low flooded riparian reserve forest in Punjab Pakistan

2020 ◽  
Vol 29 (2) ◽  
pp. e016
Author(s):  
Asma Mansoor ◽  
Faiza Sharif ◽  
Sharoon Hanook ◽  
Laila Shahzad ◽  
Amin-U. Khan
Keyword(s):  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Ecological Status ◽  
Basal Area ◽  
Soil Characteristics ◽  
Stem Density ◽  
Shannon Diversity ◽  
Reserve Forest ◽  
Hill Numbers ◽  
Stand Basal Area

Aim of Study: The complex community of riparian reserve forest has become of great concern for researchers to develop more viable management strategies. The paper aimed to evaluate the current structural diversity of vegetation and its association with the physical environment of low-lying forest for proposing the rehabilitation interventions.  Area of Study: We studied two forests, Chung-Mohlanwal and Dhana-Bheni on both riverbanks along river Ravi in the Jhok riparian reserve forest situated in the southwest of Lahore, Pakistan.Material and Methods: A methodological framework was developed based firstly, on direct comparison of diversity (measured by Hill numbers) and structure of existed vegetation layers (trees, shrubs, herbs, and grasses) and environmental factors (canopy structure, anthropogenic activities, microclimate, and soil characteristics) between the two forests and secondly, on environment-vegetation association using Canonical Correspondence Analysis (CCA) ordination method.Results: Dhana forest was more diverse vegetation layers (Shannon Diversity index 1D < 11) and intact due to plantation of uneven-aged tree stands of varied stand basal area and stem density. Microclimate under this forest could not support the dominant understory positively unlike the monoculture forest. On the contrary, Chung-Mohlanwal forest was under the influence of uncontrolled grazing activities, fuelwood extraction, and invasive species. Multivariate analysis CCA elucidated that most variance was shown by soil characteristics (38.5 %) for understory vegetation in both forests.Research Highlights: Overstory stand structure, species composition, distance to nearby communities, and soil characteristics should be considered for developing forest planting and management strategies.Keywords: Vegetation Structure; Hill Numbers; Grazing; Environment; Management.Abbreviation used: CCA (Canonical Correspondence Analysis); 1D (Shannon Diversity); Ca + Mg (Calcium + Magnesium); Na (Sodium); ECe (Electrical Conductivity); DBH (Diameter at Breast Height); IUCN (International Union for Conservation of Nature); SBA (Stand Basal area); BA (Basal Area); 0D (Richness); 2D (Simpson Index); IVI (Importance Value Index); LU (Livestock Unit); GPS (Global Positioning System); OC (Organic Carbon); OM (Organic matter); SAR (Sodium Adsorption Ratio); N (Nitrogen); P (Phosphorous); K (Potassium); DCA (Detrended Correspondence Analysis); S (Shrub); H (Herb); G (Grass).

Dynamics of dead wood in old-growth hemlock–hardwood forests of northern Wisconsin and northern Michigan

1994 ◽  
Vol 24 (8) ◽  
pp. 1672-1683 ◽  
Author(s):  
Lucy E. Tyrrell ◽  
Thomas R. Crow
Keyword(s):  
Tree Mortality ◽  
Structural Integrity ◽  
Dead Wood ◽  
Woody Debris ◽  
Basal Area ◽  
Exponential Model ◽  
Decay Rates ◽  
Permanent Plots ◽  
Old Growth ◽  
Northern Michigan

We studied the dynamics of coarse woody debris (logs and snags) in old-growth forests by estimating rates of tree mortality, snag change, and log decay in hemlock–hardwood stands located in northern Wisconsin and northern Michigan. To estimate mortality and snag changes, we recensused live trees and dead snags in permanent plots in 15 stands. We also recorded recent mortality along transects, and noted category of mortality (standing death, breakage, or uprooting) for gap-maker trees and logs in 25 stands. Decay rates were estimated from a simple exponential model of wood density from log sections against the age of the wood since tree death, and from ages of trees growing on decaying "nurse" logs. From data obtained in permanent plots, annual tree mortality averaged 0.9% original basal area, 0.9% original live tree density, and 4.8 trees/ha. Of the three categories of tree mortality, standing death accounted for 62% of all mortality, while breakage represented 25%, and uprooting, 13%. Based on origin of logs, species composition affected category of mortality. Eastern hemlock (Tsugacanadensis (L.) Carr.) was significantly more prone to uprooting while yellow birch (Betulaalleghaniensis Britton) and paper birch (Betulapapyrifera Marsh.) were less prone to uprooting than expected if independence of species and categories of mortality were assumed (χ2 = 216.5, df = 14, p < 0.001). Changes in snags (fragmentation to shorter snags or collapse at the base) occurred for <7% of the original snags annually. Fragmentation occurred for 2.1 snags/(ha × year), and collapse for 1.3 snags/(ha × year). We estimated that it takes nearly 200 years for hemlock logs to lose structural integrity and become partially incorporated into the soil. At >350 years, the two oldest hemlock–hardwood stands had accumulated volumes of logs >65 m3/ha distributed among all decay classes, and appeared to be at a dead wood equilibrium in which rates of log production from mortality balance rates of wood loss by decay.

The Ice Storm in Eastern Canada 1998 KAMEDO-Report No. 74

2001 ◽  
Vol 16 (1) ◽  
pp. 50-52 ◽  
Author(s):  
Louis Riddex ◽  
Uno Dellgar
Keyword(s):  
Emergency Services ◽  
Electrical Power ◽  
Emergency Department Visits ◽  
Ice Storm ◽  
Structured Interviews ◽  
Eastern Canada ◽  
Essential Services ◽  
Generating Equipment ◽  
Tract Infections ◽  
The Impact

AbstractThis is a report of the impact of the ice storm that struck eastern Canada on 04–09 January 1998. The storm deposited ice some 100 mm thick on the ground and on the electric power lines and eventually left 1.4 million households and much of the infrastructure without electrical power.Data were obtained through non-structured interviews of those involved. Most of the larger hospitals were equipped with emergency generating equipment and were able to provide most essential services. For most hospitals, non-emergency services were compromised. Many other medical facilities, including clinics had to be shut down, and smaller hospitals were forced to transfer some patients to larger institutions. In addition, hospitals experienced a marked increase in the number of emergency department visits including an increase in the number of persons with injuries, respiratory tract infections, or heart problems. A marked increase in carbon-monoxide intoxication was observed: 50 persons required the use of hyperbaric oxygen and six persons died of CO poisoning.Prehospital services not only experienced a marked increase in the number of emergency responses, but also were utilized to provide transportation of non-ill or injured persons, equipment, and supplies. Home care was interrupted and many patients dependent upon power had to be transported to hospitals. Many hospitals opened their buildings to provide shelter to the families of many of their employees and medical staff. This helped to keep staffing at a better level than if they had to find shelter and essential services elsewhere.The transmission and sharing of information was severely limited due in part to the loss of power and inability to access television. This led to the distribution of misleading or incorrect information.This storm was exemplary of our dependence upon electrical power and that we are not prepared to cope with the loss of electricity.

The impact of two harvesting systems on residual stems in a partially cut stand of northern hardwoods

1994 ◽  
Vol 24 (2) ◽  
pp. 350-357 ◽  
Author(s):  
M.T. Nichols ◽  
R.C . Lemin Jr. ◽  
W.D. Ostrofsky
Keyword(s):  
Conventional Treatment ◽  
Basal Area ◽  
Partial Cutting ◽  
Northern Hardwood ◽  
Harvesting Systems ◽  
Stand Damage ◽  
The Impact ◽  
Residual Stand Damage ◽  
Stand Basal Area ◽  
Better Than

Residual stand damage was evaluated following partial cutting with a mechanical and a conventional harvesting system in a northern hardwood stand in Maine. Damage from harvesting using a swing to bunch feller–buncher and grapple skidder was compared with damage from a chainsaw and cable skidder operation. Harvesting resulted in actual residual basal areas of 10 and 16.5 m2/ha in a heavy and light conventional treatment, respectively, and in 9 and 6.9 m2/ha in two mechanized treatments. The proportion of stems wounded averaged 22–44% in the conventional, and 20–31% in the mechanized operation. Wounds were significantly (p < 0.05) longer in the heavy conventional [Formula: see text] treatment than in light conventional [Formula: see text] and mechanized ([Formula: see text] and 60.2 cm) treatments. Wounds were located higher on the stems in the 9 m/ha mechanized [Formula: see text] than in the 10 m2/ha conventional treatment [Formula: see text]. A separate survey of the mechanized harvest showed that season of harvest (winter vs. summer) significantly affected wound location and the wound width to tree circumference ratio. A model was developed that relates harvesting treatment (light and heavy conventional and two heavy mechanical), species, distance of a stem from the edge a skid trail or access corridor, and initial stand basal area to the probability of injuring an individual stem. Mechanized harvesting using equipment with long-reach swing to bunch felling capability appears to be better than some other mechanical systems, and no worse than conventional harvesting systems, but the need to further reduce damage levels is evident.

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