scholarly journals Immediate and Delayed Effects of Severe Winds on an Old-Growth Forest in Kentucky: A Forty-Year Retrospective

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 271 ◽  
Author(s):  
Susan Jones-Held ◽  
Michael Held ◽  
Joe Winstead ◽  
William Bryant
Keyword(s):  
Sugar Maple ◽  
Forest Canopy ◽  
Basal Area ◽  
The United States ◽  
Tree Regeneration ◽  
Forest Recovery ◽  
Total Density ◽  
Old Growth Forest ◽  
Long Term Studies

Wind disturbance is an important factor that can affect the development of the forests of the Central Hardwood Region of the United States. However, there have been few long-term studies of the recovery of these systems following wind damage. Long-term studies of protected forest systems, such as Dinsmore Woods in Northern Kentucky, within the fragmented forest of this region are valuable as they provide a resource to document and understand the effect of both abiotic and biotic challenges to forest systems. This study is a 40-year analysis of both overstory and understory changes in the forest system at Dinsmore Woods as the result of damage caused by severe winds in the spring of 1974. The forest was surveyed before and immediately following the windstorm and then at 10-year intervals. Although the windstorm had an immediate effect on the forest, the pattern of damage was complex. The forest canopy (diameter at breast height (DBH) ≥ 30 cm) experienced an irregular pattern of damage while in the subcanopy (DBH ≤ 30 cm) there was a 25% reduction in total basal area. However, the major effects of the windstorm were delayed and subsequently have altered forest recovery. Ten years following the disturbance declines were seen in total density and basal area in the canopy and subcanopy of the forest as a consequence of windstorm damage. In the past 20 years the total basal area of the canopy has increased and exceeds the pre-disturbance total basal area. In contrast, the subcanopy total basal area continued to decline 20 years post-disturbance and has not recovered. Further openings in the canopy and subcanopy due to the delayed windstorm effects helped to establish a dense understory of native shrubs and sugar maple which have affected tree regeneration and is reflected in the continual decline in species diversity in the subcanopy and sapling strata over the 40-year period.

scholarly journals Severity of Overstory Mortality Influences Conifer Recruitment and Growth in Mountain Pine Beetle-Affected Forests

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 536 ◽  
Author(s):  
Kristen Pelz ◽  
Charles Rhoades ◽  
Robert Hubbard ◽  
Frederick Smith
Keyword(s):  
High Mortality ◽  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Basal Area ◽  
Tree Regeneration ◽  
Forest Recovery ◽  
Subalpine Fir ◽  
Advance Regeneration ◽  
Mountain Pine ◽  
Pine Beetle

The severity of lodgepole pine mortality from mountain pine beetle outbreaks varies with host tree diameter, density, and other structural characteristics, influencing subcanopy conditions and tree regeneration. We measured density and leader growth of shade-intolerant lodgepole pine, shade-tolerant Engelmann spruce, and very shade-tolerant subalpine fir regeneration beneath stands that experienced moderate and high overstory lodgepole pine mortality (average 40% and 85% of total basal area) a decade earlier. Lodgepole comprised >90% of the overstory basal area and mature spruce and fir were present in both mortality levels, though live basal area and disturbance history differed. Post-beetle outbreak recruitment was high in both mortality levels, but there were more lodgepole in high than moderate mortality plots (1140 stems ha−1 vs. 60 stems ha−1) and more subalpine fir in moderate than high mortality plots (4690 stems ha−1 vs. 2870 stems ha−1). Pine advance regeneration, established prior to outbreak, was more dense in high mortality than moderate mortality sites (930 stems ha−1 vs. 310 stems ha−1), but the trend was generally the opposite for the other conifers. Lodgepole recruitment increased and subalpine fir decreased with greater forest floor light availability. All species grew faster in high mortality areas than their counterparts in moderate mortality areas. However, in high mortality areas pine grew faster than the more shade tolerant species, and in moderate mortality areas spruce and fir grew faster than pine. These species-specific responses to the degree of overstory mortality will influence future stand composition and rate of forest recovery after mountain pine beetle outbreaks.

scholarly journals Long-Term Effects of Fuels Treatments, Overstory Structure, and Wildfire on Tree Regeneration in Dry Forests of Central Washington

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 888
Author(s):  
Allison K. Rossman ◽  
Jonathan D. Bakker ◽  
David W. Peterson ◽  
Charles B. Halpern
Keyword(s):  
Prescribed Burning ◽  
Basal Area ◽  
Tree Regeneration ◽  
Dry Forest ◽  
Permanent Plots ◽  
Long Term Effects ◽  
Fuels Reduction ◽  
Forest Fuels ◽  
Fuels Treatments

The long-term effectiveness of dry-forest fuels treatments (restoration thinning and prescribed burning) depends, in part, on the pace at which trees regenerate and recruit into the overstory. Knowledge of the factors that shape post-treatment regeneration and growth is limited by the short timeframes and simple disturbance histories of past research. Here, we present results of a 15-year fuels-reduction experiment in central Washington, including responses to planned and unplanned disturbances. We explore the changing patterns of Douglas-fir regeneration in 72 permanent plots (0.1 ha) varying in overstory abundance (a function of density and basal area) and disturbance history—the latter including thinning, prescribed burning, and/or wildfire. Plots were measured before treatment (2000/2001), soon afterwards (2004/2005), and more than a decade later (2015). Thinning combined with burning enhanced sapling recruitment (ingrowth) into the overstory, although rates of ingrowth were consistently low and greatly exceeded by mortality. Relationships between seedling frequency (proportion of quadrats within a plot) and overstory abundance shifted from weakly negative before treatment to positive after thinning, to neutral in the longer term. However, these relationships were overshadowed by more recent, higher-severity prescribed fire and wildfire that stimulated seedling establishment while killing advanced regeneration and overstory trees. Our results highlight the dependence of regeneration responses on the history of, and time since, fuels treatment and subsequent disturbance. Managers must be aware of this spatial and temporal complexity and plan for future disturbances that are inevitable but unpredictable in timing and severity.

Long-term impact of liming on growth and vigor of northern hardwoods

2011 ◽  
Vol 41 (6) ◽  
pp. 1295-1307 ◽  
Author(s):  
Robert P. Long ◽  
Stephen B. Horsley ◽  
Thomas J. Hall
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Keystone Species ◽  
Basal Area ◽  
Fagus Grandifolia ◽  
Northern Hardwood ◽  
Crown Health ◽  
Lime Application ◽  
Species Specific

Sugar maple (Acer saccharum Marsh.) is a keystone species in the northern hardwood forest, and decline episodes have negatively affected the growth and health of sugar maple in portions of its range over the past 50+ years. Crown health, growth, survival, and flower and seed production of sugar maple were negatively affected by a widespread decline event in the mid-1980s on the unglaciated Allegheny Plateau in northern Pennsylvania. A long-term liming study was initiated in 1985 to evaluate responses to a one-time application of 22.4 Mg·ha–1 of dolomitic limestone in four northern hardwood stands. Over the 23-year period ending in 2008, sugar maple basal area increment (BAINC) increased significantly (P ≤ 0.05) in limed plots from 1995 through 2008, whereas American beech (Fagus grandifolia Ehrh.) BAINC was unaffected. For black cherry (Prunus serotina Ehrh.), the third principal overstory species, BAINC and survival were reduced in limed plots compared with unlimed plots. Foliar Ca and Mg remained significantly higher in sugar maple foliage sampled 21 years after lime application, showing persistence of the lime effect. These results show long-term species-specific responses to lime application.

scholarly journals Impacts of Thinning Strategies on Financial Returns from Yellow-Poplar Stands

1999 ◽  
Vol 23 (2) ◽  
pp. 69-77 ◽  
Author(s):  
Matthew H. Pelkki
Keyword(s):  
Basal Area ◽  
Site Index ◽  
The United States ◽  
Financial Returns ◽  
Yellow Poplar ◽  
Stem Quality ◽  
High Site ◽  
Initial Improvement ◽  
Composite Wood

Abstract In the central and southern Appalachian region of the United States, yellow-poplar is an important timber resource for the sawmill and composite wood industries. A dynamic programming optimization algorithm was used to evaluate financial returns from various thinning strategies on yellow-poplar stands. Improvement thinning was found to increase long-term returns more than any other thinning strategy on most combinations of site and stand quality. Only on a high site index stand with a stem distribution dominated by high quality trees was thinning from above found to be the most valuable strategy. When stands have low or average stem quality distributions, the typical rotation has one to two thinnings removing 20% to 35% of the basal area in each thinning. Timing of the initial improvement thinning ranges from 22-32 yr, and occurs earlier in higher site index stands. In stands of high stem quality, one to five thinnings removing 20% to 40% of the basal area are employed, and rotation length increases as production shifts to sawtimber. Stands with higher site index and stem quality distributions have higher numbers of thinnings. This research demonstrates the value of intermediate treatments in improving financial returns from yellow-poplar. South. J. Appl. For. 23(2):69-77.

scholarly journals Novel Insights to Be Gained From Applying Metacommunity Theory to Long-Term, Spatially Replicated Biodiversity Data

2021 ◽  
Vol 8 ◽  
Author(s):  
Sydne Record ◽  
Nicole M. Voelker ◽  
Phoebe L. Zarnetske ◽  
Nathan I. Wisnoski ◽  
Jonathan D. Tonkin ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
The United States ◽  
Biodiversity Patterns ◽  
Spatial And Temporal Scales ◽  
Long Term Ecological Research ◽  
Spatial Replication ◽  
Spatio Temporal ◽  
Long Term Studies ◽  
Observation Networks

Global loss of biodiversity and its associated ecosystem services is occurring at an alarming rate and is predicted to accelerate in the future. Metacommunity theory provides a framework to investigate multi-scale processes that drive change in biodiversity across space and time. Short-term ecological studies across space have progressed our understanding of biodiversity through a metacommunity lens, however, such snapshots in time have been limited in their ability to explain which processes, at which scales, generate observed spatial patterns. Temporal dynamics of metacommunities have been understudied, and large gaps in theory and empirical data have hindered progress in our understanding of underlying metacommunity processes that give rise to biodiversity patterns. Fortunately, we are at an important point in the history of ecology, where long-term studies with cross-scale spatial replication provide a means to gain a deeper understanding of the multiscale processes driving biodiversity patterns in time and space to inform metacommunity theory. The maturation of coordinated research and observation networks, such as the United States Long Term Ecological Research (LTER) program, provides an opportunity to advance explanation and prediction of biodiversity change with observational and experimental data at spatial and temporal scales greater than any single research group could accomplish. Synthesis of LTER network community datasets illustrates that long-term studies with spatial replication present an under-utilized resource for advancing spatio-temporal metacommunity research. We identify challenges towards synthesizing these data and present recommendations for addressing these challenges. We conclude with insights about how future monitoring efforts by coordinated research and observation networks could further the development of metacommunity theory and its applications aimed at improving conservation efforts.

scholarly journals Effects of fire and thinning on Kansas oak woodlands

2017 ◽  
Author(s):  
◽  
Mary Faith Short
Keyword(s):  
Prescribed Fire ◽  
Sugar Maple ◽  
Basal Area ◽  
The United States ◽  
Tree Density ◽  
Canopy Openness ◽  
First Year ◽  
Herbaceous Plant ◽  
Basal Diameter ◽  
Advance Regeneration

Prior to Euro-American settlement, a mosaic of prairie, savanna, woodland, and forest existed within the Forest-Prairie Transition Region of the United States, with anthropogenic fire acting as an important driver in the perpetuation of open-oak communities. As fire suppression became a regular practice throughout the 20th century, these historically open communities became threatened by encroaching fire-sensitive, and often shade-tolerant, species. This study evaluated the effects of prescribed fire and thinning treatments as methods to achieve woodland restoration objectives, which commonly include reducing stand density, reducing mesophytic oak-competitors, increasing canopy openness, increasing herbaceous plant cover, and promoting the regeneration of oak. We investigated the effects of six treatment types on the structure and composition of a Kansas oak woodland. Treatments included: prescribed fire (burn), thin to 60 ft sq/acre basal area (T60), thin to 30 ft sq/acre basal area (T30), the combination of fire and thin to 60 ft sq/acre basal area (BT60), the combination of fire and thin to 30 ft sq/acre basal area (BT30), and an untreated control. Additionally, we examined the effect of fire on advance regeneration survival probability for five tree species: chinkapin oak (Quercus muehlenbergii), black oak (Q. velutina), bitternut hickory (Carya cordiformis), sugar maple (Acer saccharum), and eastern redcedar (Juniperus virginiana). Following a single girdle and herbicide application thinning treatment, we found low mortality in the first year, especially for sugar maple. As a result, the reduction in overstory basal area did not meet our intended targets. A single dormant season prescribed burn was effective at reducing large and small seedling densities of sugar maple and other oak-competitors, and increased forb and legume cover in the understory. However, the burn only treatment had no effect on overstory stand metrics, including basal area, tree density, percent stocking, and canopy openness. Thinning of the overstory and midstory in combination with prescribed fire resulted in similar effects to seedling densities and ground flora cover as the burn only treatment, but also created reduced tree density in the sapling layer and greater canopy openness. Additionally, the effect of the burn only treatment on advance regeneration revealed that significant relationships exist between pretreatment stem basal diameter and height and the probability of surviving a single fire for some of the species. These initial results are for the first year following treatments and over time we expect vegetation dynamics to continue to respond to treatments.

Effets des coupes d'éclaircie et des variations climatiques interannuelles sur la production et la teneur en sucre de la sève d'une érablière

1995 ◽  
Vol 25 (11) ◽  
pp. 1815-1820 ◽  
Author(s):  
David Pothier
Keyword(s):  
Sap Flow ◽  
Sugar Maple ◽  
Basal Area ◽  
Temperature Fluctuations ◽  
Winter Precipitation ◽  
Climatic Conditions ◽  
Sugar Concentration ◽  
Meteorological Variables ◽  
Strongly Correlated

A study was initiated in 1975 on a sugar maple (Acersaccharum Marsh.) stand of the Station forestière de Duchesnay (46°57′N, 71°39′W) to determine the effect of thinning on sap production of sugar maple. From 1975 to 1989, spring sap flow and sugar concentration were measured in 58 sample plots distributed in five blocks within which three intensities of thinning (0, 22, and 35% of the initial basal area) were applied. Thinning intensities only accounted for a small part of the variation in sap volume per tap and sap sugar concentration. However, more than 60% of the variation of these two sap characteristics was related to year-to-year variations. This suggests that sap yield and sap sugar concentration were largely controlled by the different climatic conditions that occurred during these years. Hence, sap yield was strongly correlated with the number of days characterized by temperature fluctuations around 0 °C during springtime and by winter precipitation. Sap sugar concentration was also correlated to the number of days with temperature fluctuating around 0 °C during springtime but all other tested meteorological variables failed to improve this relationship. While thinning intensities did not affect sap yield per tap and sugar concentration, sugar yield per hectare could be improved by thinning over the long term since it increased the potential number of taps per hectare.

Designing dementia treatment studies: Diagnosis, efficacy criteria, and duration

1996 ◽  
Vol 11 (3) ◽  
pp. 149-154 ◽  
Author(s):  
R Spiegel ◽  
P Irwin
Keyword(s):  
United States ◽  
Return On Investment ◽  
The United States ◽  
Regulatory Requirements ◽  
Regulatory Guidelines ◽  
Efficacy Criteria ◽  
Feasible Study ◽  
Long Term Studies ◽  
Symptomatic Benefit

SummaryDevelopment of treatments for dementia is beset by special problems in defining the diagnosis, establishing efficacy criteria, and specifying the necessary duration of study. There is need for agreement among clinicians and scientists on diagnostic subgroups of dementia. Similarly, there is a need for harmonization of the regulatory guidelines in Europe, Japan, and the United States regarding the decision set of variables on which to base efficacy claims. The duration of trials must be based upon the intended claim: transient symptomatic benefit, maintained symptomatic benefit, or a therapeutic effect on disease progression. Claims other than transient benefit require long-term trials, suggested to be of at least six months in duration. Problems with long-term studies include slow patient accrual, high dropout rates, changing milieu, low return on investment, and lack of unanimity regarding regulatory requirements. Regulatory authorities must come to some accord, consonant with current clinical/scientific wisdom and consensus, regarding diagnosis, efficacy criteria, and feasible study duration, in order to attract continued sponsor investment in the development of antidementia treatments.

scholarly journals Recovery of Forest Structure Following Large-Scale Windthrows in the Northwestern Amazon

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 667
Author(s):  
J. David Urquiza Muñoz ◽  
Daniel Magnabosco Marra ◽  
Robinson I. Negrón-Juarez ◽  
Rodil Tello-Espinoza ◽  
Waldemar Alegría-Muñoz ◽  
...  
Keyword(s):  
Forest Structure ◽  
Large Scale ◽  
Tree Mortality ◽  
Basal Area ◽  
Forest Recovery ◽  
Old Growth ◽  
Study Region ◽  
Central Amazon ◽  
Old Growth Forest ◽  
Study Sites

The dynamics of forest recovery after windthrows (i.e., broken or uprooted trees by wind) are poorly understood in tropical forests. The Northwestern Amazon (NWA) is characterized by a higher occurrence of windthrows, greater rainfall, and higher annual tree mortality rates (~2%) than the Central Amazon (CA). We combined forest inventory data from three sites in the Iquitos region of Peru, with recovery periods spanning 2, 12, and 22 years following windthrow events. Study sites and sampling areas were selected by assessing the windthrow severity using remote sensing. At each site, we recorded all trees with a diameter at breast height (DBH) ≥ 10 cm along transects, capturing the range of windthrow severity from old-growth to highly disturbed (mortality > 60%) forest. Across all damage classes, tree density and basal area recovered to >90% of the old-growth values after 20 years. Aboveground biomass (AGB) in old-growth forest was 380 (±156) Mg ha−1. In extremely disturbed areas, AGB was still reduced to 163 (±68) Mg ha−1 after 2 years and 323 (± 139) Mg ha−1 after 12 years. This recovery rate is ~50% faster than that reported for Central Amazon forests. The faster recovery of forest structure in our study region may be a function of its higher productivity and adaptability to more frequent and severe windthrows. These varying rates of recovery highlight the importance of extreme wind and rainfall on shaping gradients of forest structure in the Amazon, and the different vulnerabilities of these forests to natural disturbances whose severity and frequency are being altered by climate change.

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.

Sign in / Sign up

Export Citation Format

Share Document