scholarly journals Natural regeneration of senescent even-aged beech (Fagus sylvatica L.) stands under the conditions of Central Bohemia

2009 ◽  
Vol 55 (No. 4) ◽  
pp. 144-145 ◽  
Author(s):  
L. Bílek ◽  
J. Remeš ◽  
D. Zahradník
Keyword(s):  
Fagus Sylvatica ◽  
Natural Regeneration ◽  
Seedling Emergence ◽  
Ground Vegetation ◽  
High Survival ◽  
Outer Face ◽  
Crown Cover ◽  
Silvicultural Treatments ◽  
The Mean ◽  
Selection Harvesting

The natural regeneration of beech (<I>Fagus sylvatica</I> L.) was studied under various shelterwood densities and silvicultural treatments in senescent beech stands in Central Bohemia. Four permanent research plots differed in shelterwood density, crown cover and average relative light intensities. Between 2003 and 2007, seed production, seedling emergence and survival were followed. The mean density of beech seeds (full and empty) per 1 m<sup>2</sup> was estimated in another forest stand. In the autumn of 2003 the values were distinctly higher than those indicated for full mast years of beech. Despite high losses during the wintering of seeds, relatively low germination and high first-season mortality, the high density of 1-year-old beech seedlings indicates that these elements are not the factors which hinder natural regeneration. The thickness of the humus horizons influenced the density of young beech seedlings during all the three years. Ground vegetation was more frequent outside the crown projections of parent trees and increased with distance from the nearest tree. A reduction of crown cover to the level of 80% was an appropriate measure that assured the high survival of beech regeneration during the observed four-year period. Border cutting with the outer face oriented towards the east has to be considered as less suitable for beech regeneration than shelterwood systems and group selection harvesting.

scholarly journals Seed Germination in Cistus ladanifer: Heat Shock, Physical Dormancy, Soil Temperatures and Significance to Natural Regeneration

Plants ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 63 ◽  
Author(s):  
Luís Silva Dias ◽  
Isabel Pires Pereira ◽  
Alexandra Soveral Dias
Keyword(s):  
Heat Shock ◽  
Seed Germination ◽  
Natural Regeneration ◽  
Heat Load ◽  
Fire Effects ◽  
Ground Vegetation ◽  
Cistus Ladanifer ◽  
Physical Dormancy ◽  
Soil Temperatures ◽  
Heat Loads

Seeds of Cistus ladanifer experience bursts of germination following fires. The effects of heat shock from 10 °C to 150 °C on seed germination were investigated by final germination plus the number of days required for germination to start and finish, and symmetry of cumulative germination. The occurrence of physical dormancy in C. ladanifer seeds was investigated by a variety of methods, including imbibition, scanning electron microscopy (SEM) and light microscopy, and use of dyes. The significance of responses of C. ladanifer seeds to fires was investigated essentially by abstracting existing literature and by using fire effects models and simulations. Parameters of germination were variously affected by heat treatments—positively in the range 80–100 °C, negatively above 130 °C. Non-dormancy was consistently found in about 30% of seeds but no evidence was obtained to support the existence of physical dormancy in the dormant fraction of C. ladanifer seeds. Two complementary processes seem to be in place in seeds response to fire. A direct fire-driven increase in germination of virtually all seeds in response to the appropriate heat load produced by fire or, in the absence of such heat loads, the germination of the non-dormant fraction provided that above-ground vegetation burns.

scholarly journals Forest Management Intensity: A Comparison of Timber Investment Management Organizations and Industrial Landowners in Mississippi

2003 ◽  
Vol 27 (2) ◽  
pp. 83-91 ◽  
Author(s):  
Ian A. Munn ◽  
W. Rhett Rogers
Keyword(s):  
Forest Management ◽  
Natural Regeneration ◽  
Management Practices ◽  
Response Rate ◽  
Pine Plantations ◽  
Property Taxes ◽  
Investment Management ◽  
Chemical Release ◽  
Silvicultural Treatments ◽  
Management Intensity

Abstract All timberland investment management organizations (TIMOs) and industrial landowners in Mississippi were surveyed during 1998 and 1999 to determine their annual forest management practices and related expenditures. The response rate was 65%, and respondents accounted for approximately 90% of the timberland owned by these two landowner groups. For analysis purposes, industrial landowners were separated into two categories: large (>10,000 ac) and small (<10,000 ac). Pine plantations represented 66% of TIMOs' timberland base compared to 55% for large industrial landowners and less than 50% for small industrial landowners. Over the 2 yr study period, TIMOs and large industrial landowners invested heavily in site preparation and planting as well as midrotation chemical release and fertilization. In contrast, small industrial landowners relied on natural regeneration to a much greater extent and conducted few, if any, midrotation treatments. As a group, TIMOs and industrial landowners spent approximately $20/ac annually on their Mississippi timberlands. Overhead represented slightly over 40% of this total, with silvicultural treatments accounting for the remainder. Property taxes represented the largest overhead expense. In total, these landowners spent $67 million in 1998 and $54 million in 1999 to maintain and manage their Mississippi timberlands. South. J. Appl. For. 27(2):83–91.

The development of seed quality in spring barley in four environments. II. Field emergence and seedling size

1991 ◽  
Vol 1 (3) ◽  
pp. 179-185 ◽  
Author(s):  
C. Pieta Filho ◽  
R. H. Ellis
Keyword(s):  
Hordeum Vulgare ◽  
Seed Quality ◽  
Spring Barley ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Physiological Maturity ◽  
Production Environments ◽  
The Mean ◽  
Field Emergence ◽  
Positive Correlations

AbstractThe field emergence ability of a total of 88 seed lots of spring barley (Hordeum vulgare L.) harvested serially during development in 2 years was compared, as was the size of the resultant seedlings. For seedsproduced in each year, field emergence and the mean dry weight of emerged seedlings were significantly greater for seed lots harvested some timeafter physiological maturity (end of the seed-filling period) than for those harvested at or before this developmental stage. This is compatiblewith results for the potential longevity of these lots. It is concluded that barley seed quality continues to increase after physiological maturity, and that the developing seeds attain maximum quality (however this is assessed) close to when the seed crop can be combine harvested. Positive correlations were detected between seedling emergence and seed dry weight (P<0.05) and between the mean dry weight of emerged seedlings and seed dry weight (P<0.005) among seed lots harvested close to when maximum quality was attained in four seed production environments.

scholarly journals Growth Rate Variation and Larval Survival: Inferences from an Individual-Based Size-Dependent Predation Model

1993 ◽  
Vol 50 (1) ◽  
pp. 133-142 ◽  
Author(s):  
James A. Rice ◽  
Thomas J. Miller ◽  
Kenneth A. Rose ◽  
Larry B. Crowder ◽  
Elizabeth A. Marschall ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Individual Variability ◽  
Individual Growth ◽  
Rate Variation ◽  
High Survival ◽  
Initial Growth ◽  
Size Dependent ◽  
The Mean ◽  
Selection For

We used an individual-based Monte Carlo simulation model to explore how changes in the mean and variance of growth rates of individuals in a larval fish cohort interact with size-dependent predation to affect the number and characteristics of individual survivors. Small changes in initial cohort mean growth rate can change survival over the first 60 d of life 10-to 30-fold. But when variance in growth rate among individuals is high, survival can be substantially higher than expected from the initial mean cohort growth rate. Selection for faster-growing individuals becomes stronger with increasing variance and increasing predation rate. In some cases, > 80% of the survivors may come from the upper 25% of the initial growth rate distribution, and the mean growth rate of the survivors may exceed twice the initial mean growth rate. When individual growth rates change from day to day rather than remaining constant, the contribution of atypical individuals is accentuated even further. Counterintuitively, most of the selection for faster-growing individuals happens only after the majority of mortality has already taken place. These results suggest that interactions between individual variability and selective mortality may have important cohort-level implications for survival in fishes.

scholarly journals Seedling emergence and early growth of Chinese fir under different light levels and seed positions: implications for natural regeneration

2018 ◽  
Vol 48 (9) ◽  
pp. 1034-1041 ◽  
Author(s):  
Bo Liu ◽  
Qingqing Liu ◽  
Stefani Daryanto ◽  
Xiangqing Ma ◽  
Si Guo ◽  
...  
Keyword(s):  
Natural Regeneration ◽  
Southern China ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Light Level ◽  
Early Growth ◽  
Chinese Fir ◽  
Light Levels ◽  
Light Requirements ◽  
Moisture Conditions

Chinese fir, Cunninghamia lanceolata (Lamb.) Hook. (Taxodiaceae), is an evergreen conifer primarily distributed in southern China. This species exhibits very poor natural regeneration, possibly due to low light and a thick litter layer. To improve the understanding of the natural regeneration capacity of Chinese fir, in this study, we conducted a shade house experiment to determine the optimum light requirements and seed positions for seedling emergence and early growth. The experiment involved five light levels (100%, 60%, 40%, 15%, 5% of full sunlight) and four seed positions (1 cm beneath the soil surface without litter, on the soil surface without soil–seed contact, on the soil surface and covered with litter, and 1 cm beneath the soil surface and covered with litter). Seedling emergence was highest at 5%–15% sunlight, whereas seedling height, root length, root mass, stem mass, leaf mass, and total mass were highest at 60% sunlight. For each light level, seed position significantly affected emergence and growth. The above-litter position inhibited seedling emergence and survival, while the below-litter position favored seedling emergence and early growth, particularly under high light levels. Based on these results, to enhance natural regeneration of Chinese fir, we recommend periodical thinning to increase light into the understory after successful seedling emergence. We also recommend sowing seeds deeper into the litter to improve soil contact and moisture conditions.

Comparative responses of small mammals, vegetation, and food sources to natural regeneration and conifer release treatments in boreal balsam fir stands of Quebec

1999 ◽  
Vol 29 (7) ◽  
pp. 1128-1140 ◽  
Author(s):  
Nancy Gagné ◽  
Louis Bélanger ◽  
Jean Huot
Keyword(s):  
Small Mammals ◽  
Natural Regeneration ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Rubus Idaeus ◽  
Balsam Fir ◽  
Food Sources ◽  
Ground Vegetation ◽  
Growing Seasons ◽  
Advance Regeneration

Abundance and species diversity of small mammals were compared among three regeneration methods used in boreal balsam fir (Abies balsamea (L.) Mill.) forests. Those methods were natural regeneration after "careful logging" to retain advance regeneration and planting (black spruce, Picea mariana (Mill.) BSP) followed by herbicide (Vision®) release or brushsaw cutting release. Deciduous vegetation was reduced for two growing seasons in both plantation types after treatment, and foliar arthropods decreased for one growing season. In herbicide-treated plantations, red raspberry (Rubus idaeus L.) shrub cover, near-ground vegetation, and production of berries were reduced for two growing seasons. After herbicide release, the abundance of the red-backed vole (Clethrionomys gapperi (Vigors)) was significantly lowered for two growing seasons. This negative effect was associated with reduced cover during the first two post-treatment growing seasons. In the short term, herbicide-treated plantations constitute poorer red-backed vole habitats than brushsaw plantations. In early successional boreal balsam fir stands, planting did not markedly affect small mammals probably because natural regeneration was common in these plantations.

Natural regeneration of Fagus sylvatica L. adapts with maturation to warmer and drier microclimatic conditions

2012 ◽  
Vol 275 ◽  
pp. 60-67 ◽  
Author(s):  
Silvija Bilela ◽  
Aikaterini Dounavi ◽  
Barbara Fussi ◽  
Monika Konnert ◽  
Jutta Holst ◽  
...  
Keyword(s):  
Fagus Sylvatica ◽  
Natural Regeneration ◽  
Fagus Sylvatica L ◽  
Microclimatic Conditions

scholarly journals Survival of dental implants in patients with bone dysplasia: A systematic review

2021 ◽  
Vol 8 (4) ◽  
pp. 8
Author(s):  
Alexandre Perez ◽  
Sarah Dib ◽  
Andreij Terzic ◽  
Delphine Courvoisier ◽  
Paolo Scolozzi
Keyword(s):  
Dental Implants ◽  
Survival Rates ◽  
Bone Dysplasia ◽  
Bone Lesions ◽  
Cleidocranial Dysplasia ◽  
High Survival ◽  
Osseous Dysplasia ◽  
The Mean ◽  
Reporting Data

Objective: This study used published studies to assess the survival rate of dental implants placed in patients with bone dysplasia of the maxillofacial region.Material and methods: An electronic search without a specified date range was performed using the MEDLINE, PubMed, EMBASE, Web of Science, and Cochrane databases. No gender or age restrictions were applied.Results: Eighteen publications were found that met the study’s criteria, reporting data on 18 patients with bone dysplasia including cleidocranial dysplasia (CDD), fibrous dysplasia (FD), florid cemento-osseous dysplasia (FCOD), and odonto-maxillary segmental dysplasia (SOMD), who received a total of 130 implants, an average of 7.2 implants/patient (range 1 to 16). The mean age of the patients was 36.7 years (range 15 to 70 years). For implants placed in bone dysplasia, the survival rates were 100% for patients with CDD (n = 8), FD (n = 5), SOMD (n = 2), FCOD with implants inserted far from the lesions (n = 2) and 0% for dental implants inserted within FCOD (n = 1). The mean follow-up was 38.2 months (min 6, max 60).Conclusions: Dental implants placed in patients with dysplastic bone lesions show high survival rates, similar to those in the general population for CDD, FD, and SOMD. For FCOD, the failure rate was 100%.

scholarly journals Effect of soil scarification on natural regeneration of mature scots pine (Pinus sylvestris) stands in Greece

2014 ◽  
Vol 16 (4) ◽  
pp. 732-742 ◽  
Keyword(s):  
Scots Pine ◽  
Natural Regeneration ◽  
Climatic Conditions ◽  
Ground Vegetation ◽  
Soil Scarification ◽  
Pine Stands ◽  
Scots Pine Forest ◽  
Set Up ◽  
Positive Effect ◽  
Scots Pine Stands

<div> <p>The natural regeneration of Scots pine stands at the Sarakatsana location in the Pieria Mountains improved considerably after the removal of the dense ground vegetation followed mechanical soil scarification. The experimental design consisted of replications on scarified and non-scarified soil. The results four years after the experiment was set up showed that regeneration reached 59 seedlings m-2 in scarified and 7 seedlings m-2 in non-scarified soil. Soil scarification seems to have had a positive effect on the emergence and survival of naturally regenerated Scots pine. The negligible number of dead seedlings in the first two measurements could be due to the favourable site and/or good climatic conditions. Although the mother stand appears to be in a critical condition due to age and increased necrosis as a result of fungal attacks, there is still considerable potential for regeneration in terms of fructification and seed production. The study findings indicate that there can be new growth of Scots pine forest with the shelterwood method of natural regeneration in combination with soil scarification.</p> </div> <p>&nbsp;</p>

Sign in / Sign up

Export Citation Format

Share Document