Influence of stand age and physical environment on the herb composition of second-growth forest, Strouds Run, Ohio, USA

2006 ◽  
Vol 33 (6) ◽  
pp. 1139-1149 ◽  
Author(s):  
Sarah M. Harrelson ◽  
Glenn R. Matlack
Keyword(s):  
Physical Environment ◽  
Stand Age ◽  
Second Growth

scholarly journals Análisis florístico de la vegetación secundaria derivada de la selva húmeda de montaña de Santa Cruz Tepetotutla (Oaxaca) México

2017 ◽  
pp. 89
Author(s):  
Marco Antonio Romero-Romero ◽  
Silvia Castillo ◽  
Jorge Meave ◽  
Hans Van der Wal
Keyword(s):  
Life Forms ◽  
Stand Age ◽  
Considerable Proportion ◽  
Santa Cruz ◽  
Montane Rain Forest ◽  
Secondary Vegetation ◽  
Forest Region ◽  
Tree Ferns ◽  
Second Growth ◽  
Productive Systems

A floristic analysis war conducted of the secondary vegetation derived from slash and burn agriculture in a montane rain forest region at Santa Cruz Tepetotutla, located in the Northern Oaxaca Range, Mexico. The analysis of the studied chronosequence is based on a collection of 2 668 specimens encountered in 60 parallel 0.01 ha belt transects (25 X 4 m), distributed in 18 second-growth stands with ages ranging between 5 and ca. 100 years. A total of 499 species were distinguished, which are distributed in 223 genera and 104 families (including 38 secondary vegetation species collected outside of the transects), among which the following growth forms are represented: trees, shrubs, herbs, herbaceous and woody climbers, palms, ferns, and epiphytes. Only 28 morphospecies were not determined to any taxonomic level. Floristic richness did not decrease nor increased significantly with stand age. In contrast, changing trends, albeit non significant, were observed for different life forms, as arboreal species gradually replaced herbaceous ones, whereas palms and tree ferns only appeared in stands of intermediate age and their abundances increased thereof. The results of this study suggest that a considerable proportion of the regional floristic diversity occurs in the secondary vegetation. The abandonment of traditional agricultural methods for modern but usually inadequate, productive systems threatens this floristic potential, because it affects characteristics of the system fundamental for the maintenance of species, such as stand age and the area of the primary vegetation matrix in which these stands are embedded.

Western gall rust dynamics and impact in young lodgepole pine stands in west-central Alberta

1988 ◽  
Vol 18 (11) ◽  
pp. 1437-1442 ◽  
Author(s):  
I. E. Bella ◽  
S. Navratil
Keyword(s):  
Lodgepole Pine ◽  
Management Strategies ◽  
Volume Growth ◽  
Analysis Data ◽  
Stand Age ◽  
Site Factors ◽  
Second Growth ◽  
Younger Age ◽  
Life Impact ◽  
The Impact

A sample of 29 405 lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) trees was assessed from 1982 to 1985, and stem analysis data of 75 trees from five heavily infested second-growth stands in the foothills of the Rockies were analyzed to determine the incidence, development, and impact of western gall rust Endocronartiumharknessii (J.P. Moore) Y. Hiratsuka, in relation to age of trees and stand and site factors. The incidence of western gall rust increased with stand age and time. In stands up to 12 years old, the incidence averaged about 5% and increased rapidly to about 20% at age 20. A rapid increase in incidence over time occurred in younger age-classes. In stands 20 years or older, the incidence of new infection was low. Mortality associated with western gall rust among crop trees was low. There was, however, 30% mortality in an unthinned 22-year-old stand over its life. Impact on growth was highly significant (p < 0.01). In the periods 11–15 years and 16–20 years after the wave of heavy infection, reductions in volume growth of infected crop trees were 15 and 25%, respectively. This loss amounts to 15% of the total volume over the 20-year period during which the stands are affected. Western gall rust incidence was higher (p < 0.01) in stands on east-facing slopes than on south- and north-facing slopes. Stands at elevations between 1200 and 1400 m had the highest incidence. Forest management strategies to reduce the impact of western gall rust are discussed, with emphasis on spacing that includes sanitary removal of infected trees.

Diversity of ectomycorrhizae on experimentally planted Douglas-fir seedlings in variable retention forestry sites on southern Vancouver Island

2004 ◽  
Vol 82 (11) ◽  
pp. 1671-1681 ◽  
Author(s):  
R A Outerbridge ◽  
J A Trofymow
Keyword(s):  
Root Colonization ◽  
Distance Effect ◽  
Vancouver Island ◽  
Douglas Fir ◽  
Stand Age ◽  
Mature Trees ◽  
Old Growth ◽  
Variable Retention ◽  
Second Growth ◽  
Retention Forestry

Studies were done on Vancouver Island of ectomycorrhizal (EM) communities at four distances (5–45 m) from isolated forest patches in three second-growth (SG) and three old-growth (OG) Douglas-fir sites subject to variable retention harvesting. We tested the hypothesis that retention of mature trees enhances colonization and diversity of EM fungi on seedlings planted in adjacent areas. In total 41 EM morphotypes were described, with mean diversity of 3.47 morphotypes and root colonization of 62% per seedling. Overall, root colonization declined with distance (72% at 5 m vs. 52% at 45 m), as did EM diversity (4.7 at 5 m vs. 2.9 at 45 m). For individual sites, the distance effect was significant for root colonization at four sites and for EM diversity at three to four sites. This suggests that variable retention is important for the recovery of ectomycorrhizal biota in harvested sites. Seedling root colonization was significantly lower in SG sites than in OG sites. Though EM diversity did not differ with stand age, OG sites had potentially more total (34) and unique (14) EM morphotypes than did SG sites (total 27, unique 7). Differences with stand age might be related to the relative abilities of EM fungi to disperse to regenerating second-growth forests.Key words: variable retention silviculture, ectomycorrhizae ecology, Douglas-fir seedlings, old growth, second-growth forests.

Characteristics of northern flying squirrel populations in young second- and old-growth forests in western Oregon

1992 ◽  
Vol 70 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Daniel K. Rosenberg ◽  
Robert G. Anthony
Keyword(s):  
Body Mass ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Stand Age ◽  
Glaucomys Sabrinus ◽  
Old Growth ◽  
Flying Squirrel ◽  
Flying Squirrels ◽  
Northern Flying Squirrel ◽  
Second Growth

We compared density, sex ratio, body mass, and annual recapture rate of northern flying squirrel (Glaucomys sabrinus) populations in second-growth and old-growth Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Cascade Range. Densities averaged 2.0 and 2.3 squirrels/ha in second- and old-growth stands, respectively. Although densities varied between years within stands, average densities were similar between years. Body mass and annual recapture rate were similar between stand–age classes, although a higher proportion of females was recaptured in subsequent years in second-growth than in old-growth stands. Similarly, there was a higher proportion of females than males in second-growth but not in old-growth stands. Squirrel densities were not correlated with habitat characteristics; we concluded that flying squirrels may be habitat generalists, and not a species associated with old-growth stands, as was previously hypothesized. We suggest that studies be carried out with radiotelemetry to more accurately assess the habitat associations of this species.

Long-term recovery of vegetation communities after harvesting in the coastal temperate rainforests of northern British Columbia

2008 ◽  
Vol 38 (12) ◽  
pp. 3098-3111 ◽  
Author(s):  
Allen Banner ◽  
Philip LePage
Keyword(s):  
British Columbia ◽  
Species Richness ◽  
Thuja Plicata ◽  
Stand Age ◽  
Terrestrial Vegetation ◽  
Old Growth ◽  
Second Growth ◽  
Old Growth Forests ◽  
Young Forests ◽  
Logging Disturbance

We sampled second-growth forests ranging in age from 28 to 98 years and compared them with old-growth forests to quantify rates of terrestrial vegetation recovery following harvesting on the northcentral coast of British Columbia. Species richness approximately doubles, while Simpson’s index of diversity increases from 0.81 to 0.91 from young to old forests. Nonmetric multidimensional scaling ordinations showed differentiation, with some overlap, of old-growth and second-growth forests and a fairly strong correlation of stand age with plot scores, driven by plant species presence and cover. Vegetation succession following logging disturbance is driven primarily by predisturbance species composition; most species found in the young forests are present in old forests and the higher species richness typical of old growth is largely due to the establishment of additional cryptogam and herb species of low cover and constancy. Significantly higher cover of shrub, herb, and bryophyte species differentiates old forests from second-growth forests. Forests 41–100 years old average 63%–73% similarity (depending on site type) to old-growth forests based on species presence–absence and 53%–58% similarity based on species cover. The scarcity of western redcedar ( Thuja plicata Donn ex D. Don) in second-growth stands is of particular concern because of the high ecological, cultural, and economic importance of this tree species.

EFFECTS OF CLIMATE AND STAND AGE ON ANNUAL TREE DYNAMICS IN TROPICAL SECOND-GROWTH RAIN FORESTS

Ecology ◽  
2005 ◽  
Vol 86 (7) ◽  
pp. 1808-1815 ◽  
Author(s):  
Robin L. Chazdon ◽  
Alvaro Redondo Brenes ◽  
Braulio Vilchez Alvarado
Keyword(s):  
Stand Age ◽  
Rain Forests ◽  
Second Growth

scholarly journals Seed Bank Variation under Contrasting Site Quality Conditions in Mixed Oak Forests of Southeastern Ohio, USA

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Christine J. Small ◽  
Brian C. McCarthy
Keyword(s):  
Seed Bank ◽  
Soil Disturbance ◽  
Site Quality ◽  
Stand Age ◽  
Timber Species ◽  
Ecosystem Recovery ◽  
Second Growth ◽  
Commercially Important ◽  
Topographic Aspect ◽  
Intensive Sampling

Seed bank composition was sampled in 192–2.5 m2quadrats, established in six regenerating clearcut (∼7 years) and six second-growth (∼125 years) mixed-oak forest stands in southeastern Ohio. Seed bank and aboveground composition diverged markedly (Sørensen's coefficient <10%), emphasizing the importance of fast-growing, early-successional germinants to early ecosystem recovery. Seed richness was significantly (P<.01) higher in clearcut stands, suggesting declining richness with stand age. Richness estimations 28%–60% higher than observed values demonstrated high seed bank heterogeneity, emphasizing the need for intensive sampling to assess temperate forest seed bank variation. Site quality (topographic aspect) strongly influenced seed bank composition, with greater importance of early-successional trees, thicket-forming shrubs, and nonnative species on mesic sites. Thus, forest seed banks are likely to play an important, site-dependent role in shaping competitive environments for commercially important timber species after harvesting and soil disturbance and have the potential for marked influence on postharvest forest development.

Differences in lichen and bryophyte communities between old-growth and managed second-growth forests in the Swan Valley, Montana

1991 ◽  
Vol 69 (8) ◽  
pp. 1745-1755 ◽  
Author(s):  
Peter Lesica ◽  
Bruce McCune ◽  
Stephen V. Cooper ◽  
Won Shic Hong
Keyword(s):  
Woody Debris ◽  
Structural Diversity ◽  
Stand Age ◽  
Old Growth ◽  
Lobaria Pulmonaria ◽  
Β Diversity ◽  
Rotting Wood ◽  
Second Growth ◽  
Northwestern Montana ◽  
Old Growth Forests

Lichen and bryophyte communities differed between managed second-growth and unmanaged old-growth grand fir forests in northwestern Montana in all three strata examined: lower canopy, trunk, and ground. Old-growth forests had larger trees, greater structural diversity, greater volumes of coarse woody debris, fewer species of vascular plants, more species of trunk epiphytes, higher β diversity, and higher γ diversity than second-growth forests. Although pendent fruticose lichens were common in both stand age classes, species of Alectoria were more abundant in old growth, while second growth was dominated by Bryoria spp. Nitrogen-fixing foliose lichens were more common in all strata of old growth, and Lobaria pulmonaria, a common N-fixing species in old growth, was absent in second growth. Cladonia spp. were more numerous in second-growth forests. Nearly all species of leafy liverworts were more common in old growth and typically occurred on rotting wood. Many of these liverworts were absent from second growth. Our results suggest that many species of lichens and bryophytes find optimum habitat in old-growth forests and that these species will become less common as silvicultural practices continue to convert old growth to younger aged forests. Key words: bryophytes, diversity, forests, lichens, Montana, old growth.

Use of track transects to measure the relative occurrence of some boreal mammals in uncut forest and regeneration stands

1989 ◽  
Vol 67 (7) ◽  
pp. 1816-1823 ◽  
Author(s):  
I. D. Thompson ◽  
I. J. Davidson ◽  
S. O'Donnell ◽  
F. Brazeau
Keyword(s):  
Red Fox ◽  
Habitat Preferences ◽  
Cold Weather ◽  
Tamiasciurus Hudsonicus ◽  
Stand Age ◽  
Winter Mortality ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Clear Cut ◽  
Second Growth

Tracks of marten (Martes americana), lynx (Felis lynx), red fox (Vulpes vulpes), ermine (Mustela erminea), snowshoe hare (Lepus americanus), and red squirrel (Tamiasciurus hudsonicus) were censused from 1980 to 1985 on 1-km transects in uncut stands and on eight sites that had been clear-cut between 1 and 33 years ago, in boreal mixedwood habitat near Manitouwadge, Ontario. Marten tracks were more common in uncut areas than in younger stands. Lynx tracks were most abundant on sites that were logged 20–30 years ago and were absent in uncut areas and stands less than 5 years old. Counts of red fox tracks were lowest in uncut stands and showed no consistent pattern among years of our survey with respect to stand age in second-growth forest. Hare tracks were most abundant in 20- and 30-year-old stands, and least abundant in stands less than 5 years old. Red squirrels were most common in uncut areas, but similar high values were also found in 20- and 30-year-old sites during 3 years when populations in the area were depressed. No selection of stands by age was seen for ermine. Numbers of tracks were significantly correlated with live captures of marten, hare, and red squirrels. Our results suggested that track abundance can be used as an index of habitat preferences and population trends. Highest counts were achieved in December for marten, red squirrel, and ermine, likely as a result of several types of over-winter mortality and inactivity in cold weather, which may have reduced counts in January and March. As a result of high and nonhomogeneous variance among transects and years, nonparametric statistical analysis was required. Transect length for fox and lynx should be substantially longer than 1 km (probably 3–5 km) to avoid numerous zero results.

An Application of the HFACS Method to Aviation Accidents in Africa

2016 ◽  
Vol 6 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Isaac Munene
Keyword(s):  
Human Factors ◽  
Physical Environment ◽  
Human Factor ◽  
Flight Training ◽  
African Countries ◽  
Causal Factors ◽  
Aviation Accidents ◽  
Factors Analysis ◽  
Adverse Weather ◽  
Decision Errors

Abstract. The Human Factors Analysis and Classification System (HFACS) methodology was applied to accident reports from three African countries: Kenya, Nigeria, and South Africa. In all, 55 of 72 finalized reports for accidents occurring between 2000 and 2014 were analyzed. In most of the accidents, one or more human factors contributed to the accident. Skill-based errors (56.4%), the physical environment (36.4%), and violations (20%) were the most common causal factors in the accidents. Decision errors comprised 18.2%, while perceptual errors and crew resource management accounted for 10.9%. The results were consistent with previous industry observations: Over 70% of aviation accidents have human factor causes. Adverse weather was seen to be a common secondary casual factor. Changes in flight training and risk management methods may alleviate the high number of accidents in Africa.

Sign in / Sign up

Export Citation Format

Share Document