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.

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.

scholarly journals Influences of Forest Type, Stand Age, and Weather on Deer Weights and Antler Size in the Southern Appalachians

1997 ◽  
Vol 21 (1) ◽  
pp. 11-18 ◽  
Author(s):  
William M. Ford ◽  
A. Sydney Johnson ◽  
Philip E. Hale ◽  
James M. Wentworth
Keyword(s):  
Age Structure ◽  
Forest Type ◽  
Site Index ◽  
Forest Stand ◽  
Site Quality ◽  
Stand Age ◽  
Southern Appalachians ◽  
Study Region ◽  
Pinus Spp ◽  
Percent Area

Abstract We analyzed correlations of forest type, age structure, and site index data with weights and antler characteristics of yearling white-tailed deer (Odocoileus virginianus) bucks from specific localities in the Chattahoochee, Cherokee, Nantahala, and Pisgah national forests in Georgia, Tennessee, and North Carolina. Areas in the northern part of the study region produced larger deer with larger antlers than those in the southern portion of the region. These northern areas differed from those to the south in having more diverse ownership and land use and in origins of deer stock. Weights and antler characteristics were significantly correlated (P < 0.05) with percent area in the cove hardwood type, but otherwise were poorly correlated with forest stand type and site index. Percent area in young (0-8 yr old) cove hardwood and in mid-successional (9-20 and 21-40) cove hardwood, pine (Pinus spp.), and upland oak (Quercus spp.) were significantly correlated (P < 0.05) with deer variables, particularly in years following a poor mast crop. Much of the quantifiable habitat influences on deer in the Southern Appalachians probably is masked by low deer densities and the small site quality differences among areas examined. Because much of the forest consists of mature mast-producing oaks and abundant forage is produced in both mature and younger aged stands, deer numbers seem to be below any threshold of quantifiable effects due to forest stand age structure. South. J. Appl. For. 21(1):11-18.

scholarly journals Effect of Plot Size on Estimates of Top Height in Douglas-Fir

1999 ◽  
Vol 14 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Steen Magnussen
Keyword(s):  
Douglas Fir ◽  
Growth Potential ◽  
Site Quality ◽  
Plot Size ◽  
Height Estimates ◽  
Second Growth ◽  
Height Predictions ◽  
Relationship Of ◽  
Simulated Sampling ◽  
The Impact

Abstract Top height is frequently used to estimate site quality and growth potential of forest stands. Top height estimates are quantile estimators and thus sensitive to scaling. If top height is defined as the height of the largest dbh tree per 0.01 ha of area, then it follows that any estimate based on ntop trees in a ntop · 0.01 plot will be a function of ntop, the distribution of dbh values, and the height-diameter relationship of the stand. This study quantifies for second-growth Douglas-fir (Pseudotsuga menziesii) stands along the west coast of British Columbia top height estimates derived from plots of size 0.01, 0.03, 0.05, and 1.0 ha. A pool of 635 permanent and remeasured sample plots allowed the estimation of expected stand-level diameter distributions (Weibull) and height-diameter relationships. Simulated sampling from these distributions quantified the impact of plot size. Top height, derived from plots of 0.01 ha, 0.03 ha and 0.05 ha were 5.6%, 3.0%, and 2.5% lower, respectively, than the estimates based on 1.0 ha plots. Yield predictions based on top heights from 0.01 ha plots were, on average, 8% lower than predictions from 1.0 ha plots. Three of four top height predictions based on 0.01 ha plots were significantly (P < 0.05) lower than predictions from a 1.0 ha plot. West. J. Appl. For. 14(1):17-27.

scholarly journals Wood Properties Characterisation of Thermo-Hydro Mechanical Treated Plantation and Native Tasmanian Timber Species

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1189
Author(s):  
Michelle Balasso ◽  
Andreja Kutnar ◽  
Eva Prelovšek Niemelä ◽  
Marica Mikuljan ◽  
Gregory Nolan ◽  
...  
Keyword(s):  
Mass Loss ◽  
Wood Properties ◽  
High Water ◽  
Radiata Pine ◽  
Wood Products ◽  
Timber Species ◽  
Final Thickness ◽  
Dimensional Changes ◽  
Commercially Important ◽  
Shining Gum

Thermo-hydro mechanical (THM) treatments and thermo-treatments are used to improve the properties of wood species and enhance their uses without the application of chemicals. This work investigates and compares the effects of THM treatments on three timber species from Tasmania, Australia; plantation fibre-grown shining gum (Eucalyptus nitens H. Deane and Maiden), plantation saw-log radiata pine (Pinus radiata D. Don) and native-grown saw-log timber of the common name Tasmanian oak (which can be any of E. regnans F. Muell, E. obliqua L’Hér and E. delegatensis L’Hér). Thin lamellae were compressed by means of THM treatment from 8 mm to a target final thickness of 5 mm to investigate the suitability for using THM-treated lamellas in engineered wood products. The springback, mass loss, set-recovery after soaking, dimensional changes, mechanical properties, and Brinell hardness were used to evaluate the effects of the treatment on the properties of the species. The results show a marked increase in density for all three species, with the largest increase presented by E. nitens (+53%) and the smallest by Tasmanian oak (+41%). E. nitens displayed improvements both in stiffness and strength, while stiffness decreased in P. radiata samples and strength in Tasmanian oak samples. E. nitens also displayed the largest improvement in hardness (+94%) with respect to untreated samples. P. radiata presented the largest springback whilst having the least mass loss. E. nitens and Tasmanian oak showed similar dimensional changes, whilst P. radiata timber had the largest thickness swelling and set-recovery due to the high water absorption (99%). This study reported the effects of THM treatments in less-known and commercially important timber species, demonstrating that the wood properties of a fibre-grown timber can be improved through the treatments, potentially increasing the utilisation of E. nitens for structural and higher quality timber applications.

Increased weed emergence and seed bank depletion by soil disturbance in a no-tillage system

Weed Science ◽  
1997 ◽  
Vol 45 (2) ◽  
pp. 234-241 ◽  
Author(s):  
Dawit Mulugeta ◽  
David E. Stoltenberg
Keyword(s):  
Seed Bank ◽  
Seedling Emergence ◽  
Soil Disturbance ◽  
No Tillage ◽  
Common Lambsquarters ◽  
Redroot Pigweed ◽  
Giant Foxtail ◽  
Tillage System ◽  
Level Of Aggregation ◽  
Viable Seeds

The influence of secondary soil disturbance on the emergence pattern and seed bank depletion of an annual weed community in a long-term, no-tillage corn cropping system was determined in 1992 and 1993. As a component of this research, the seed bank was characterized prior to implementation of soil disturbance treatments. The seed bank was initially composed of common lambsquarters, redroot pigweed, and giant foxtail, with approximately 55, 36, and 8% of the total viable seeds, respectively. The remaining 1% was comprised of five other species in 1992 and eight in 1993. The spatial distribution of viable seeds of each species, except common lambsquarters and redroot pigweed, was described by a negative binomial distribution. Three dispersion indices indicated that seeds of individual and total weed species were aggregated and that the level of aggregation of viable seeds of a species was associated with seed density; at lower seed densities, the level of aggregation was greater. Soil disturbance increased common lambsquarters emergence 6-fold in 1992 relative to nondisturbed soil, but did not influence emergence in 1993. Rainfall was about 50% less in 1993. In contrast, soil disturbance increased giant foxtail and redroot pigweed emergence approximately 6- and 3-fold in 1992 and 1993, respectively. Seedling emergence associated with soil disturbance, relative to nondisturbed soil, increased seed bank depletion of common lambsquarters 16-fold in 1992, and giant foxtail and redroot pigweed and average of 6- and 3-fold in 1992 and 1993, respectively. These results indicated that soil disturbance increased seedling emergence and seed bank depletion of the predominant species in the weed community of a long-term, no-tillage system, but that this response was dependent on rainfall for common lambsquarters.

Weed infestation during the transition phase from conventional to conservation agriculture

2020 ◽  
Author(s):  
Felice Sartori ◽  
Donato Loddo ◽  
Ilaria Piccoli ◽  
Antonio Berti
Keyword(s):  
Species Richness ◽  
Seed Bank ◽  
Conservation Agriculture ◽  
Soil Disturbance ◽  
Transition Phase ◽  
Effective Control ◽  
Silty Clay ◽  
Weed Species ◽  
Number Of Species ◽  
Weed Species Richness

&lt;p&gt;Despite conservation agriculture and, overall, the reduction of soil disturbance are considered soil improving cropping systems, these practices could conflict with weed control. Indeed, reduced tillage is usually linked to increased weed species richness and abundance and, thus, it could increase the dependence on chemical treatments. Weed management is one of the reasons behind the distrust of European farmers in the conservation agriculture, that is still not widespread, despites European subsidies. In fact, conservation agriculture is implemented only in the 2.8% of European cropland.&lt;/p&gt;&lt;p&gt;The aim of this study is to evaluate the effect of different tillage intensities on spring-summer weeds richness and abundance in a maize monoculture, during the transition phase from conventional to conservation agriculture.&lt;/p&gt;&lt;p&gt;The weed survey was conducted in June 2019 on an experiment comparing three levels of tillage management: conventional agriculture (CT), which represents the most common choice in Veneto region, involving deep ploughing and harrowing in spring; minimum tillage (MT), consisting only in harrowing at 20 cm; and no tillage (NT), namely sod seeding. The experiment started in 2018, at Padova University experimental farm, in a sub-humid area, with a silty clay loam soil. The survey was conducted with a set of random throws of a 30&amp;#215;30 cm square frame in each plot (ca. 3300 m&lt;sup&gt;2&lt;/sup&gt;). &amp;#160;Weed plants found within the frame were classified and counted. Subsequently, data analysis assessed which botanical families were promoted by each treatment.&lt;/p&gt;&lt;p&gt;The NT resulted the treatment with the highest weed density (915 plant/m&lt;sup&gt;2&lt;/sup&gt;): 6% higher than MT (823 plant/m&lt;sup&gt;2&lt;/sup&gt;) and four-fold more than CT (209 plant/m&lt;sup&gt;2&lt;/sup&gt;). The latter showed to be the treatment with higher diversity, according to both Shannon and Simpson indices. The survey evidenced higher weed species richness in MT, where both annual and perennial species were identified, while the lowest number of species were detected in NT. Plantago major and Chenopodium album were the species with the highest density in CT (&gt;32 plant/m&lt;sup&gt;2&lt;/sup&gt;) while they are negligible in NT and MT (7 plant/m&lt;sup&gt;2&lt;/sup&gt;, on average). Digitaria sanguinalis was instead the dominant species in MT and NT (&gt;600 plant/m&lt;sup&gt;2&lt;/sup&gt;) while a lower density was observed in CT (11 plant/m&lt;sup&gt;2&lt;/sup&gt;). Low levels of Asteraceae weeds were measured in all treatments. These results shows that the actual flora rapidly changes depending on tillage intensity, with an increase of both dominance and number of species in MT. Differently, only a limited number of adapted species germinated in NT, despite higher infestations if compared with the other treatments.&lt;/p&gt;&lt;p&gt;It should be expected that other species more adapted to conservation agriculture (namely Asteraceae), still marginally present in the seed bank, will spread in the next years. This stresses the importance of a continuous monitoring and effective control of weeds to avoid uncontrolled evolutions of the weed flora and increase of seed bank in the transition phase from conventional to conservation agriculture.&lt;/p&gt;

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.

scholarly journals Stand growth model using volume increment/basal area ratios

2008 ◽  
Vol 54 (No. 3) ◽  
pp. 102-108 ◽  
Author(s):  
J. Martínez Pastur G ◽  
M. Cellini J ◽  
V. Lencinas M ◽  
L. Peri P
Keyword(s):  
Simple Model ◽  
Growth Models ◽  
Basal Area ◽  
Site Quality ◽  
Stand Age ◽  
Full Density ◽  
Nothofagus Pumilio ◽  
Stand Growth ◽  
Mean Error ◽  
Volume Increment

Estimation of stand growth is crucial for forest planning. Estimations were usually done using fixed values, and recently growth equations have been used. An alternative is through stand growth models. The objective was to develop a simple model for<I> Nothofagus pumilio</I> stands with full density along site quality and age gradients. The sample was obtained from 125 stands. Data on forest structure and samples for tree-ring measurement were taken in all trees to estimate growths using biometric models previously developed. The growth values of each plot during the last twenty years were calculated to fit the model, using the ratio of total volume increment/basal area as an independent variable. The developed model gives a ratio between stand volume increment and basal area (m/year) in relation to the site quality and stand age. The statistics (<I>r</I><sup>2</sup> = 0.819, mean error = 0.019, absolute mean error = 0.033), residual analysis and biological performance were satisfactory. The obtained stand growths varied between 1 and 20 m<sup>3</sup>/ha/year. This simple model allowed to estimate growth values at a stand level from easy field measurements from forest inventories.

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