scholarly journals LONG-TERM RELATIONSHIP BETWEEN OAK DECLINE AND SHRUB GROWTH DYNAMICS IN AN HUNGARIAN OAK FOREST, 1972-2017

AGROFOR ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Tamás MISIK ◽  
Imre KÁRÁSZ
Keyword(s):  
Growth Dynamics ◽  
Basal Area ◽  
Tree Density ◽  
Oak Forest ◽  
Oak Decline ◽  
Shrub Layer ◽  
Cornus Mas ◽  
Oak Trees ◽  
Oak Tree

Long-term structural dynamics of shrub layer of temperate oak forest communities were not extensively reported in published studies. The serious oak decline was first reported in 1979-80 and nowadays 63.0% of canopy oak trees died in a forest stand. The data were used to obtain (1) quantitative information on shrub layer growth, including height (H) and shoot diameter (DSH) condition and basal area (BA) values; (2) structural information on foliage cover rate of the shrub layer, mean cover of some shrub species; (3) comprehensive description from the ecological processes in the shrub layer in the last 45 years and our objective was (4) to analyze the possible effects of oak decline on the shrub growth dynamics. The following measurements were carried out in the 48 × 48 m plot: shoot height, shoot diameter, basal area and foliage cover of each individuals in the high shrub layer. Correlation analysis confirmed that significant positive relations were between mean H, mean DSH of the dominant woody species (Acer campestre, Acer tataricum and Cornus mas) and oak tree density between 1972 and 2017. The decreasing oak tree density did not show detectable impact to the co-dominant shrubs growth. There was a low significant association between number of oak trees and basal area of high shrub layer. Finally, there was a statistically significant interaction between mean cover of A. campestre and C. mas and oak trees. The findings of the study indicate that forest responded to oak decline with significant structural rearrangement in the shrub layer.

scholarly journals Long-term response of understorey cover, basal area and diversity to stand density in a mixed oak forest on the Síkfőkút plot in Hungary

2013 ◽  
Vol 59 (No. 8) ◽  
pp. 319-327 ◽  
Author(s):  
T. Misik ◽  
K. Varga ◽  
Zs. Veres ◽  
I. Kárász ◽  
B. Tóthmérész
Keyword(s):  
Structural Information ◽  
Basal Area ◽  
Stand Density ◽  
Natural Disturbance ◽  
Diversity Indices ◽  
Oak Forest ◽  
Oak Decline ◽  
Shrub Species ◽  
Shrub Layer ◽  
Cornus Mas

The serious oak decline was reported for the 1979–80 period and 63.0% of adult oaks died in a mixed oak forest in the Síkfőkút site, Hungary. The data were used to obtain (1) quantitative information on diversity indices of shrub layer and shrub canopy, including foliage cover percentage of the shrub layer, mean cover of shrub species before and after the oak decline and (2) structural information on shrub basal area and shrub foliage arrangement. Since 1972 we have determined diversity indices, cover percentage and basal area of shrubby vegetation on the monitoring and plus plots. A negative relation was detected between Shannon-Wiener and Evenness indices of the shrub layer and living oak tree density. A positive relation was confirmed between basal area and mean cover of dominant woody species (Acer campestre, Acer tataricum and Cornus mas). The mean cover of shrub species except of A. campestre increased non-significantly after the oak decline on the 48 m × 48 m plot. The findings of the study indicate that diversity indices of the shrub layer and mean cover of A. campestre can be used as a principal indicator of natural disturbance in the studied mature stand and the species of the shrub layer respond differently to the decreasing stand density.  

scholarly journals Understory Development in an Oak Forest in Northern -Hungary: the Subcanopy Layer

2014 ◽  
Vol 10 (1) ◽  
pp. 9-21 ◽  
Author(s):  
Tamás Misik ◽  
Imre Kárász ◽  
Béla Tóthmérész
Keyword(s):  
Structural Changes ◽  
Ecological Factors ◽  
Thermal Conditions ◽  
Woody Species ◽  
Oak Forest ◽  
Oak Decline ◽  
Canopy Density ◽  
Acer Campestre ◽  
Shrub Layer ◽  
Cornus Mas

Abstract Structural changes in the shrub layer were analysed in a Hungarian oak forest after the oak decline pandemics. This paper focuses on the following questions: (1) which of the woody species tolerated better the forest conditions after oak decline? (2) What are the ecological factors that explain the successful response of woody species to changes in light and thermal conditions? In the monitoring plot, the structural condition of specimens only above 8.0 m was observed. After the appearance of oak decline some Acer campestre, Cornus mas and Acer tataricum specimens appeared that reached between 8.0-13.0 m in height. Significant differences were revealed between top canopy density and foliage cover of the subcanopy and between top canopy density and mean cover of field maple. The findings of the study indicate that the forest responded to oak decline with significant structural rearrangement in the shrub layer and that three woody species compensated for the remarkable foliage loss in the top canopy. These species formed a second crown layer directly below the canopy formed by oaks.

scholarly journals Large-scale forest landscape model, design, validation, and application in management of oak decline

2012 ◽  
Author(s):  
◽  
Wenjuan Wang
Keyword(s):  
Forest Inventory ◽  
Large Scale ◽  
Basal Area ◽  
Model Parameters ◽  
Forest Landscape ◽  
Oak Decline ◽  
Model Predictions ◽  
Forest Landscape Model ◽  
Landis Pro

Forest landscape models (FLMs) have increasingly become important tools for exploring forest landscape changes by predicting forest vegetation dynamics over large spatial scales. However, two challenges confronting FLMs have persisted: how to simulate fine, site-scale processes while making large-scale (landscape and regional) simulation feasible, and how to fully take advantage of extensive U.S. Forest Service Inventory and Analysis (FIA) data to initialize and constraint model parameters. In this dissertation, first, a new FLM, LANDIS PRO was developed. In LANDIS PRO, forest succession and dynamics are simulated by incorporating species-, stand-, and landscape-scale processes by tracking number of trees by species age cohort. Because stand-scale resource competition is achieved by implementing rather than simulating the emergent properties of stand development, LANDIS PRO is computationally efficient, which makes large-scale simulation feasible. Since model parameters and simulation results are comparatively straightforward to forest inventory data, current intensive forest inventory data can be directly applied for model initialization and to constrain model parameters. Validation of FLMs is essential to ensure users’ confidence in model predictions and achieve reliable management decision making. To date, validation of FLMs has been limited due to lack of suitable data. However, recent advances in FLMs, together with increasingly available spatiotemporal data make FLM validation feasible. In this dissertation, second, I proposed a framework for validating forest landscape projections from LANDIS PRO using Forest Inventory Analysis (FIA) data. The proposed framework incorporated data assimilation techniques to constrain model parameters and the initial state of the landscape by verifying the initialized landscape and iteratively calibrating the model parameters. The model predictions were rigorously validated against independent FIA data at multiple scales, and the long-term natural successional pattern was also verified against empirical studies. Results showed model predictions were able to capture much of the variation overtime in species basal area and tree density at stand-, landtype- , and landscape-scales. Subsequent long-term predictions of natural succession patterns were consistent with expected changes in tree species density of oak-dominated forests in the absence of disturbance. Lastly, I used LANDIS PRO, a forest landscape model that includes stand-scale species density and basal area to evaluate the potential landscape-scale effects of alternative harvest methods (thinning, clearcutting and group selection) on oak decline mitigation. Projections indicated that forest harvesting can be effective in mitigating oak decline. Group selection and clearcutting were the most effective methods in the management of oak decline in the short-term (20 years) and mid-term (50 years), respectively. However, in the long-run (100 years), there was no significant difference predicted among the three methods.

scholarly journals Vegetation structure, natural regeneration and management of Parroha community forest in Rupandehi district, Nepal

1970 ◽  
Vol 9 (9) ◽  
pp. 70-81 ◽  
Author(s):  
Rajendra Acharya ◽  
Babat Babu Shrestha
Keyword(s):  
Tree Species ◽  
Vegetation Structure ◽  
Basal Area ◽  
Size Class ◽  
Tree Density ◽  
Class Diagram ◽  
Shrub Layer ◽  
Shorea Robusta ◽  
Number Of Species ◽  
Total Tree

Understanding vegetation structure and regeneration in community forests in important for management planning. The present work was done during September to October 2005. The information on forest management practices was collected by Participatory Rural Appraisal (PRA) which included field observation, interviews and focus group discussion. A total of 125 plant species belonging to 55 families with 36 tree species, 50 shrubs and 39 herbs were recorded from the 0.7 ha sampling area. The total tree density and basal area at South-East (SE) facing slope was 595 pl/ha and 29.68 m²/ha, respectively, where Terminalia alata was the most dominant with highest importance value index (IVI). On the other hand, total tree density and basal area was 453 pl/ha and 41.78 m²/ha, respectively, at South-West (SW) facing slope, where Shorea robusta was the most dominant with the highest IVI. Total shrub/sapling density was 4708 pl/ha at SE slope and 4137 pl/ha at SW slope. Similarly, total herb/seedling density was 10.86 pl/m² at SE slope and 9.79 pl/m² at SW slope. The total number of tree species (S) in tree stage was higher at SE slope than at SW slope and the number of species in shrub layer was higher at SE slope than at SW slope. The two slopes had nearly equal number of species in herbaceous layer. Higher species diversity (H) of different lifeforms was found at SW slope. The SW slope had higher species evenness (J) and Simpson’s index of dominance (C) for all life forms than at SE slope. High similarity index for all tree, shrub/sapling and herb/seedling layers (63.63%, 84.61% and 77.10% respectively) were found between two sites. Alpha (α) diversity for shrub layer was higher at SE slope whereas beta (β) diversity for tree layer was higher at SW slope than at SE slope. Regeneration of Shorea robusta and Terminalia alata was continuous because density increased from tree, sapling to seedlings with a typical reverse J shaped size class diagram at both slope. But regeneration of S. robusta at SW slope was sporadic. The reccurence of forest fire during summer season has appeared as a major problem for the management of forest. The active participation of the local people in forest conservation activities can be effective for sustainable management of forest. Keywords: Community forestry; Vegetation; Regeneration; Size class diagram; Shorea robusta; Terminalia alata. DOI: http://dx.doi.org/10.3126/sw.v9i9.5523 SW 2011; 9(9): 70-81

scholarly journals Stand-level windthrow patterns and long-term dynamics of surviving trees in natural secondary stands after a stand-replacing windthrow event

2019 ◽  
Vol 92 (4) ◽  
pp. 473-480 ◽  
Author(s):  
Masato Shibuya ◽  
Satoshi Ishibashi
Keyword(s):  
Tree Mortality ◽  
Basal Area ◽  
Tree Density ◽  
Permanent Plots ◽  
Natural Forests ◽  
Canopy Layer ◽  
Breast Height ◽  
Composition And Structure ◽  
Initiation Stage

Abstract We examined typhoon windthrow patterns in stand-scale permanent plots within three natural forests and the long-term dynamics of surviving trees in two of these plots. The aim was to verify whether pre-disturbance composition and structure affected windthrow damage and stand recovery. The stands, which were in Hokkaido, the northernmost main island of Japan, differed in pre-disturbance composition (coniferous, mixed and broadleaved stands) and structure, and the basal area losses by the windthrow event were 81–93 per cent. Tree mortality was significantly related to tree size (diameter at breast height) and species. The windthrow patterns differed among the three stands; and, windthrow severity was affected by the pre-disturbance composition and structure. The mortality of trees that survived the windthrow event was ~60 per cent in the two plots. The surviving trees comprised a majority of the canopy layer in the secondary stands. The relative basal area of surviving trees decreased rapidly with increasing tree density in the stand initiation stage but differed between plots. Consequently, the pre-disturbance composition and structure influenced windthrow severity, stand recovery and secondary succession in the recovered stands.

scholarly journals Short- and long-term effects of ponderosa pine fuel treatments intersected by the Egley Fire Complex, Oregon, USA

Fire Ecology ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Jessie M. Dodge ◽  
Eva K. Strand ◽  
Andrew T. Hudak ◽  
Benjamin C. Bright ◽  
Darcy H. Hammond ◽  
...  
Keyword(s):  
Prescribed Fire ◽  
Vegetation Cover ◽  
Tree Density ◽  
Tree Canopy ◽  
Fuel Treatments ◽  
Dead Tree ◽  
High Severity ◽  
Short And Long Term ◽  
One Year

Abstract Background Fuel treatments are widely used to alter fuels in forested ecosystems to mitigate wildfire behavior and effects. However, few studies have examined long-term ecological effects of interacting fuel treatments (commercial harvests, pre-commercial thinnings, pile and burning, and prescribed fire) and wildfire. Using annually fitted Landsat satellite-derived Normalized Burn Ratio (NBR) curves and paired pre-fire treated and untreated field sites, we tested changes in the differenced NBR (dNBR) and years since treatment as predictors of biophysical attributes one and nine years after the 2007 Egley Fire Complex in Oregon, USA. We also assessed short- and long-term fuel treatment impacts on field-measured attributes one and nine years post fire. Results One-year post-fire burn severity (dNBR) was lower in treated than in untreated sites across the Egley Fire Complex. Annual NBR trends showed that treated sites nearly recovered to pre-fire values four years post fire, while untreated sites had a slower recovery rate. Time since treatment and dNBR significantly predicted tree canopy and understory green vegetation cover in 2008, suggesting that tree canopy and understory vegetation cover increased in areas that were treated recently pre fire. Live tree density was more affected by severity than by pre-fire treatment in either year, as was dead tree density one year post fire. In 2008, neither treatment nor severity affected percent cover of functional groups (shrub, graminoid, forb, invasive, and moss–lichen–fungi); however, by 2016, shrub, graminoid, forb, and invasive cover were higher in high-severity burn sites than in low-severity burn sites. Total fuel loads nine years post fire were higher in untreated, high-severity burn sites than any other sites. Tree canopy cover and density of trees, saplings, and seedlings were lower nine years post fire than one year post fire across treatments and severity, whereas live and dead tree basal area, understory surface cover, and fuel loads increased. Conclusions Pre-fire fuel treatments effectively lowered the occurrence of high-severity wildfire, likely due to successful pre-fire tree and sapling density and surface fuels reduction. This study also quantified the changes in vegetation and fuels from one to nine years post fire. We suggest that low-severity wildfire can meet prescribed fire management objectives of lowering surface fuel accumulations while not increasing overstory tree mortality.

scholarly journals Development of single-cell-level microfluidic technology for long-term growth visualization of living cultures of Mycobacterium smegmatis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Han Wang ◽  
Gloria M. Conover ◽  
Song-I Han ◽  
James C. Sacchettini ◽  
Arum Han
Keyword(s):  
Drug Treatment ◽  
Single Cell ◽  
Mycobacterium Smegmatis ◽  
Culture Media ◽  
Low Cost ◽  
Bacterial Pathogen ◽  
Growth Dynamics ◽  
Time Lapse ◽  
Cell Phenotype

AbstractAnalysis of growth and death kinetics at single-cell resolution is a key step in understanding the complexity of the nonreplicating growth phenotype of the bacterial pathogen Mycobacterium tuberculosis. Here, we developed a single-cell-resolution microfluidic mycobacterial culture device that allows time-lapse microscopy-based long-term phenotypic visualization of the live replication dynamics of mycobacteria. This technology was successfully applied to monitor the real-time growth dynamics of the fast-growing model strain Mycobacterium smegmatis (M. smegmatis) while subjected to drug treatment regimens during continuous culture for 48 h inside the microfluidic device. A clear morphological change leading to significant swelling at the poles of the bacterial membrane was observed during drug treatment. In addition, a small subpopulation of cells surviving treatment by frontline antibiotics was observed to recover and achieve robust replicative growth once regular culture media was provided, suggesting the possibility of identifying and isolating nonreplicative mycobacteria. This device is a simple, easy-to-use, and low-cost solution for studying the single-cell phenotype and growth dynamics of mycobacteria, especially during drug treatment.

Long‐term growth dynamics of natural forests in Hokkaido, northern Japan

1999 ◽  
Vol 10 (6) ◽  
pp. 815-824 ◽  
Author(s):  
Kiyoshi Umeki ◽  
Kihachiro Kikuzawa
Keyword(s):  
Growth Dynamics ◽  
Natural Forests ◽  
Northern Japan

Geostatistically modeling stem size and increment in an old-growth forest

1994 ◽  
Vol 24 (7) ◽  
pp. 1354-1368 ◽  
Author(s):  
Franco Biondi ◽  
Donald E. Myers ◽  
Charles C. Avery
Keyword(s):  
Spatial Patterns ◽  
Growth Rates ◽  
Spatial Dependence ◽  
Basal Area ◽  
Tree Density ◽  
Individual Growth ◽  
Old Growth ◽  
Model Estimate ◽  
Stem Size ◽  
Old Growth Forest

Geostatistics provides tools to model, estimate, map, and eventually predict spatial patterns of tree size and growth. Variogram models and kriged maps were used to study spatial dependence of stem diameter (DBH), basal area (BA), and 10-year periodic basal area increment (BAI) in an old-growth forest stand. Temporal variation of spatial patterns was evaluated by fitting spatial stochastic models at 10-year intervals, from 1920 to 1990. The study area was a naturally seeded stand of southwestern ponderosa pine (Pinusponderosa Dougl. ex Laws. var. scopulorum) where total BA and tree density have steadily increased over the last decades. Our objective was to determine if increased stand density simply reduced individual growth rates or if it also altered spatial interactions among trees. Despite increased crowding, stem size maintained the same type of spatial dependence from 1920 to 1990. An isotropic Gaussian variogram was the model of choice to represent spatial dependence at all times. Stem size was spatially autocorrelated over distances no greater than 30 m, a measure of average patch diameter in this forest ecosystem. Because patch diameter remained constant through time, tree density increased by increasing the number of pine groups, not their horizontal dimension. Spatial dependence of stem size (DBH and BA) was always much greater and decreased less through time than that of stem increment (BAI). Spatial dependence of BAI was close to zero in the most recent decade, indicating that growth rates in 1980–1990 varied regardless of mutual tree position. Increased tree crowding corresponded not only to lower average and variance of individual growth rates, but also to reduced spatial dependence of BAI. Because growth variation was less affected by intertree distance with greater local crowding, prediction of individual growth rates benefits from information on horizontal stand structure only if tree density does not exceed threshold values. Simulation models and area estimates of tree performance in old-growth forests may be improved by including geostatistical components to summarize ecological spatial dependence.

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