Effects of an introduced pathogen on resistance to natural disturbance: beech bark disease and windthrow

2005 ◽  
Vol 35 (8) ◽  
pp. 1832-1843 ◽  
Author(s):  
Michael J Papaik ◽  
Charles D Canham ◽  
Erika F Latty ◽  
Kerry D Woods
Keyword(s):  
Community Dynamics ◽  
Species Coexistence ◽  
Basal Area ◽  
Natural Disturbance ◽  
Fagus Grandifolia ◽  
Forest Composition ◽  
Direct Result ◽  
Betula Alleghaniensis ◽  
Beech Bark Disease ◽  
Composition And Structure

In forests of eastern North America, introduced pathogens have caused widespread declines in a number of important tree species, including dominant species such as American beech (Fagus grandifolia Ehrh.). Most studies have focused on changes in forest composition and structure as a direct result of mortality caused by a pathogen. Our field studies of windthrow resistance in forests of northern New York and northern Michigan demonstrate that resistance of beech trees to windthrow is severely reduced by beech bark disease (BBD). This reduced resistance was primarily due to the increase in the probability of stem breaks of moderately and highly infected beech trees. The severity of BBD infection on individual trees has a significant negative effect on resistance to windthrow. We tested potential consequences of this for long-term composition and structure in these forests by using a simulation model, SORTIE. We found that species such as yellow birch (Betula alleghaniensis Britt.) and eastern hemlock (Tsuga canadensis (L.) Carr.) increased in basal area primarily because of the effect BBD had on the creation of new seedbed substrates. Our results highlight the indirect effects that host-specific pathogens can have on community dynamics and species coexistence in forests.

scholarly journals The distribution and severity of beech bark disease in the Catskill Mountains, N.Y.

2003 ◽  
Vol 33 (9) ◽  
pp. 1754-1760 ◽  
Author(s):  
Jacob M Griffin ◽  
Gary M Lovett ◽  
Mary A Arthur ◽  
Kathleen C Weathers
Keyword(s):  
Spatial Scales ◽  
New York State ◽  
Host Density ◽  
Basal Area ◽  
Fagus Grandifolia ◽  
Current Status ◽  
Forest Composition ◽  
Catskill Mountains ◽  
Beech Bark Disease ◽  
Local Conditions

The distribution and severity of beech bark disease (BBD) in the Catskill Mountains of southeastern New York state, U.S.A., were measured between 1997 and 2000. Forest composition was measured using wedge prism surveys and fixed-area plot counts of canopy species. BBD severity on individual trees was ranked from 1 (no disease) to 5 (dead) based on bark health and canopy loss. These data were analyzed at multiple spatial scales to determine possible controls of disease distribution and severity. BBD was present on almost all Fagus grandifolia Ehrh. (American beech) individuals encountered >10 cm diameter at breast height, but was most severe in larger diameter classes. Mortality due to BBD also increased with diameter class. A strong positive relationship was found between BBD severity and relative beech basal area at the tract (hundreds of hectares) and 100-m elevation band spatial scales, but not found at smaller scales. Successful long-range dispersal of the disease may therefore be dependent upon host density, while local conditions may control BBD severity within individual stands. The current status of BBD in the Catskills suggests these forests are entering the aftermath phase of the disease's progression and that BBD has become an endemic component of these forests.

Using witness trees to assess forest change in southeastern Ohio

2001 ◽  
Vol 31 (10) ◽  
pp. 1708-1718 ◽  
Author(s):  
James M Dyer
Keyword(s):  
Acer Saccharum ◽  
Acer Rubrum ◽  
Fagus Grandifolia ◽  
Forest Composition ◽  
Significant Shift ◽  
Quercus Alba ◽  
Forest Change ◽  
Composition And Structure ◽  
Successional Species ◽  
Witness Trees

In 1787, the U.S. Congress authorized the sale of the "Ohio Company Purchase", ca. 5000 km2 in Appalachian Ohio. The land was surveyed using a township and range system shortly thereafter. Data on >5600 witness trees were transcribed from the survey records, and witness tree locations were plotted on a digital map. This information was used to evaluate presettlement forest composition and structure and to investigate vegetation-site relationships before widespread alteration of the forests had taken place. Presettlement conditions were compared with present conditions using forest inventory and analysis (FIA) data. Two hundred years ago, the forests of southeastern Ohio were dominated by large individuals of Quercus alba L., Carya Nutt. spp., Quercus velutina Lam., and Fagus grandifolia Ehrh. These four taxa accounted for 74% of all witness trees. Although almost 70% of the region is forested today, the second-growth forest has witnessed a decrease in Quercus and Carya and an increase in Acer saccharum Marsh., Acer rubrum L., and many early successional species in smaller size classes. Despite the significant shift in forest composition and structure, species in general seem to be occupying similar positions in the present-day landscape compared with the presettlement forest; topographic variables most strongly control species occurrence in this landscape.

Natural canopy gap disturbances and their role in maintaining mixed-species forests of central Quebec, CanadaThis article is one of a selection of papers published in the Special Forum IUFRO 1.05 Uneven-Aged Silvicultural Research Group Conference on Natural Disturbance-Based Silviculture: Managing for Complexity.

2007 ◽  
Vol 37 (9) ◽  
pp. 1534-1544 ◽  
Author(s):  
Daniel D. Kneeshaw ◽  
Marcel Prévost
Keyword(s):  
Species Coexistence ◽  
Abies Balsamea ◽  
Natural Disturbance ◽  
Canopy Gap ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
Gap Size ◽  
Gap Formation ◽  
Yellow Birch ◽  
Natural Dynamics

Until recently, natural dynamics of mixedwood stands have been largely ignored, resulting in the transformation of many North American mixedwoods into conifer- or hardwood-dominated stand types. The goal of this study was to examine canopy gap dynamics in balsam fir ( Abies balsamea (L.) Mill.) – yellow birch ( Betula alleghaniensis Britt.) mixedwoods to better understand possible mechanisms for species coexistence. Gap proportion in 12 study stands varied between 9% and 30% of the total stand area, while gap size varied from 20 to 2100 m2. Balsam fir mortality was the primary cause of gap formation. Balsam fir and mountain maple ( Acer spicatum Lamb.) dominated the tree and shrub regeneration layers, respectively. Shrub competition slows the natural filling of gaps by tree species. Our results indicate that yellow birch is most abundant in gaps over 800 m2 and balsam fir in those under 200 m2. Transition models showed that the greater longevity of yellow birch than balsam fir ensured its maintenance as a dominant. Dominant species coexistence thus results from divergent use of available resources through time and space. Forest management should maintain variability in harvest timing and size because the use of one gap size or a single rotation age will lead to an imbalance in species proportion relative to natural stands.

scholarly journals Growing-Space Relationships in Young Even-Aged Northern Hardwood Stands Based on Individual-Tree and Plot-Level Measurements

2011 ◽  
Vol 28 (1) ◽  
pp. 27-35 ◽  
Author(s):  
David Ray ◽  
Ruth D. Yanai ◽  
Ralph D. Nyland ◽  
Terry R. McConnell
Keyword(s):  
Acer Saccharum ◽  
Basal Area ◽  
Sampling Bias ◽  
Fagus Grandifolia ◽  
Analysis Of Covariance ◽  
Projection Area ◽  
Betula Alleghaniensis ◽  
Individual Tree ◽  
Northern Hardwood ◽  
Canopy Trees

Abstract The amount of growing space occupied by trees of given sizes and species is traditionally assessed on a plot basis, using observations from groups of trees growing within an area of fixed size. Our study combines individual-tree with plot-based observations of upper-canopy trees representing a range of shade tolerance (Fagus grandifolia ≥ Acer saccharum > Betula alleghaniensis ≥ Fraxinus americana) in three young, fully stocked, even-aged northern hardwood stands. The amount of canopy growing space used by a stem of given size was described by the ratios of crown projection area and crown surface area to stem basal area. These variables were related to species, stand, and relative basal area using analysis of covariance. Both ratios were generally highest in the youngest (19 years) stand, intermediate in the mid-aged stand (24 years), and lowest in the oldest stand (29 years). A few differences were detected among species, with shade-tolerants having larger ratios. Allometric models were used in conjunction with plot density data to estimate canopy cover at the stand level. Considerable crown overlap was indicated among upper-canopy trees in all three stands. Estimates from tree-centered plots suggested that crowns occupied 1.81 ± 0.02 times the ground area in the youngest stand and 1.45 ± 0.03 times in the mid-aged and oldest stands; when corrected for sampling bias, these ratios were at least 1.30 and 0.96, respectively. Combining individual-tree with plot-level measurements afforded a comprehensive assessment of trends in growing-space occupancy not possible using either technique alone.

Edge influence on composition and structure of a Pinus palustris woodland following catastrophic wind disturbance

2019 ◽  
pp. 332-341 ◽  
Author(s):  
Jonathan D. Goode ◽  
Jonathan S. Kleinman ◽  
Justin L. Hart ◽  
Arvind A.R. Bhuta
Keyword(s):  
Basal Area ◽  
Pinus Palustris ◽  
Natural Disturbance ◽  
Forest Edge ◽  
Forest Fragments ◽  
Ground Flora ◽  
Composition And Structure ◽  
Forested Ecosystems ◽  
Abiotic Interactions ◽  
Edge Influence

Forest edges are an important legacy of natural and anthropogenic disturbances. Edges of intact forest fragments are influenced by adjacent non-forested ecosystems, resulting in compositional and structural differences at the edge and into the intact forest. Edge influence (EI) is the altered biotic and abiotic interactions that occur along the edge-to-interior gradient in disturbed forests. Few studies have analyzed natural disturbance created edges, particularly in woodland structures, which contain fewer trees per hectare and are typically less light-limited than forests. The goal of our study was to examine the EI of a tornado-created edge in a Pinus palustris Mill. (longleaf pine) woodland in Alabama. In 2011, an EF-3 tornado impacted a restored P. palustris woodland, resulting in a distinct edge. We installed transects perpendicular to the edge to quantify biotic and abiotic response variables and calculate the distance of EI. Reduced structural forest complexity and basal area (negative EI) were evident 70 m into the interior woodland. Ground flora richness and diversity experienced a positive EI, with higher richness and diversity at the edge. Results of this study add to our understanding of EI on woodland composition and structure and naturally created edges and may help guide natural disturbance based silvicultural systems.

Growth Responses of Northern Hardwoods to Fertilization

1979 ◽  
Vol 25 (4) ◽  
pp. 597-604
Author(s):  
R. Lea ◽  
W. C. Tierson ◽  
A. L. Leaf
Keyword(s):  
New York State ◽  
Volume Growth ◽  
Acer Rubrum ◽  
Basal Area ◽  
Fagus Grandifolia ◽  
Betula Alleghaniensis ◽  
Growth Responses ◽  
Growth Data ◽  
Stem Form ◽  
Cross Sectional

Abstract A 70-year-old thinned Fagus-Betula-Acer stand in the Adirondack Mountains of northern New York State was fertilized with varying amounts and combinations of N, P, K, and dolomitic limestone in the spring of 1976. Betula alleghaniensis, Acer saccharum, Acer rubrum, and Fagus grandifolia growth data were obtained for two growing seasons after fertilization. Comparisons were made within species and among treatments, expressed as basal area and cross-sectional area (at 5.27 m height) growth, specific volume growth, and stem form ratio. The overall results indicate that 275 kg/ha N significantly increases radial growth with minor responses to 138 kg/ha P and lime. Potassium additions, on the whole, did not significantly alter growth rates, and individually fertilized trees grew slightly more than trees receiving entire plot applications. No changes in stem form induced by fertilization have been detected. Forest Sci. 25:597-604.

scholarly journals Forest plant and macrofungal differences in the Greater and Lesser Khingan Mountains in Northeast China: A regional-historical comparison and its implications

2021 ◽  
Author(s):  
Yuanyuan Wang ◽  
Hui Wen ◽  
Kai Wang ◽  
Jingxue Sun ◽  
Jinghua Yu ◽  
...  
Keyword(s):  
Northeast China ◽  
Dominant Species ◽  
Local Economy ◽  
Forest Composition ◽  
Historical Records ◽  
Historical Comparison ◽  
Composition And Structure ◽  
Total State ◽  
The 1960S ◽  
Forest Plants

AbstractForests in Northeast China in the Greater and Lesser Khingan Mountains (GKM and LKM) account for nearly 1/3 of the total state-owned forests in the country. Regional and historical comparisons of forest plants and macrofungi will favor biological conservation, forest management and economic development. A total of 1067 sampling plots were surveyed on forest composition and structure, with a macrofungi survey at Liangshui and Huzhong Nature Reserves in the center of two regions. Regional and historical differences of these parameters were analyzed with a redundancy ordination of their complex associations. There were 61–76 families, 189–196 genera, and 369–384 species, which was only 1/3 of the historical records. The same dominant species were larch and birch with Korean pine (a climax species) less as expected from past surveys in the LKM. Shrub and herb species were different in the two regions, as expected from historical records. There was 10–50% lower species diversity (except for herb evenness), but 1.8- to 4-time higher macrofungi diversity in the GKM. Compared with the LKM, both tree heights and macrofungi density were higher. Nevertheless, current heights averaging 10 m are half of historical records (> 20 m in the 1960s). Edible macrofungi were the highest proportion in both regions, about twice that of other fungal groups, having important roles in the local economy. A major factor explaining plant diversity variations in both regions was herb cover, followed by shrubs in the GKM and herb-dominant species in the LKM. Factors responsible for macrofungi variations were tree density and shrub height. Vaccinium vitis-idaea and Larix gmelinii in the GKM but tree size and diversity were important factors in the LKM. Our findings highlighted large spatial and historical differences between the GKM and LKM in plant-macrofungal composition, forest structure, and their complex associations, which will favor precise conservation and management of forest resources in two region in the future.

Community dynamics in Fijian coral reef fish communities vary with conservation and shark-based tourism

2019 ◽  
Vol 25 (4) ◽  
pp. 363
Author(s):  
Mallory G. McKeon ◽  
Joshua A. Drew
Keyword(s):  
Community Dynamics ◽  
Local Community ◽  
Census Data ◽  
Fish Abundance ◽  
Full Potential ◽  
Community Members ◽  
Composition And Structure ◽  
Feeding Methods ◽  
Abundance And Diversity ◽  
Unprotected Area

Marine protected areas (MPAs) effectively improve the biomass and diversity in heavily exploited marine systems, but often fail to reach their full potential because they require more space, time, and consistency of regulation. Recently, shark-based tourism, which utilises some of the remaining shark strongholds as tourism hotspots, has brought about increased awareness to exploited reef systems. In Fiji, specifically, shark diving companies include local community members in their operations to promote better understanding of their reefs. We seek to investigate whether seemingly denser shark populations during feeding times influence community composition and structure. Visual census data were collected from 50-m belt transects at four different reefs in Fiji: two MPAs with shark-based ecotourism with food provisioning, one MPA without shark-based ecotourism, and one unprotected area without shark-based tourism. Paradoxically, indices of evenness and diversity were highest in the non-protected site. However, there was significantly higher fish abundance and species diversity within reserves than outside of reserves. Within reserves, sites with shark feeding had lower fish abundance and higher richness, diversity, and evenness. Mean trophic level was highest at sites with shark feeding. Use of chum increased average fish abundance and diversity within shark-dive sites. These results indicate that there are evident differences between MPAs that do and do not offer trophic supplementation for shark-based ecotourism. Thus, tourism may be facilitating a shift of ecosystem composition in such areas. Furthermore, the results suggest that feeding methods may augment the impacts of shark-based tourism on the reef at large.

Present-day expansion of American beech in northeastern hardwood forests: Does soil base status matter?

2009 ◽  
Vol 39 (12) ◽  
pp. 2273-2282 ◽  
Author(s):  
Louis Duchesne ◽  
Rock Ouimet
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Basal Area ◽  
Base Cation ◽  
Hardwood Forests ◽  
Fagus Grandifolia ◽  
Soil Base ◽  
Large Area ◽  
American Beech ◽  
Permanent Sample Plots

Recently, sugar maple ( Acer saccharum Marsh.) decline in northeastern North America has been regarded as a major factor structuring hardwood forests by favouring American beech ( Fagus grandifolia Ehrh.) in the understory of maple-dominated stands. To determine whether soil fertility differences associated with sugar maple decline may have promoted the expansion of American beech, we explored the relationships between the soil base status and the sapling and tree strata density and composition, using data from 426 permanent sample plots distributed throughout Quebec. Our results indicate that American beech is currently expanding in the sugar maple range of Quebec. The abundance and proportion of American beech in the sapling stratum are mainly associated with the proportion of American beech in the tree stratum, the relative basal area of dead sugar maple trees, and the base status of soils. In accordance with the many studies reporting on the high sensitivity of sugar maple to the acid–base status of soils and the decline of the sugar maple population, this study supports the hypothesis that soil base cation depletion, caused in part by atmospheric acid deposition, is among the main factors involved in the present-day expansion of American beech over a large area in Quebec.

scholarly journals Management Strategies for Conservation of Tanoak in California Forests Threatened by Sudden Oak Death: A Disease-Community Feedback Modelling Approach

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1103
Author(s):  
João A. N. Filipe ◽  
Richard C. Cobb ◽  
Maëlle Salmon ◽  
Christopher A. Gilligan
Keyword(s):  
Disease Management ◽  
Community Dynamics ◽  
Management Strategies ◽  
Phytophthora Ramorum ◽  
Ecological Impacts ◽  
Control Measures ◽  
Forest Community ◽  
Forest Composition ◽  
Cumulative Impact ◽  
Modelling Approach

We use a new modelling approach to predict the cumulative impact of Phytophthora ramorum on the dynamic distribution of tanoak (Notholithocarpus densiflorus) and other tree species in coastal-Californian forest-communities. We explore the effectiveness of disease-management strategies for the conservation of tanoak at stand level. Forest resources are increasingly threatened by emerging pathogens such as P. ramorum, a generalist that kills hosts and has altered ecosystems in the USA and Europe. In coastal California, P. ramorum has the greatest impact on tanoak through leaf sporulation and lethal bole infections, but also sporulates on the common overstory-tree bay laurel (Umbellularia californica) without significant health impact. Such epidemiological differences impede host-species coexistence and challenge pathogen management. For most disease-impacted natural systems, however, empirical evidence is still insufficient to identify effective and affordable pathogen-control measures for retaining at-risk host populations. Yet, landscape-scale tree mortality requires swift actions to mitigate ecological impacts and loss of biodiversity. We apply a mathematical model of the feedback between disease and forest-community dynamics to assess the impacts of P. ramorum invasion on tanoak under stand-scale disease-management strategies by landowners aiming to retain tanoak and slow disease progression: (1) removal of inoculum through reduction of bay laurel abundance; (2) prevention of tanoak infection through chemical protection (acting epidemiologically like a vaccine); and (3) a combination strategy. The model results indicate that: (1) both bay laurel removal and tanoak protection are required to help maintain tanoak populations; (2) treatment effectiveness depends on forest composition and on threshold criteria; (3) sustainable tanoak conservation would require long-term follow-up of preventive treatments; (4) arresting basal sprouting upon tree removal may help to reduce inoculum. These findings suggest potential treatments for specific forest conditions that could be tested and implemented to reduce P. ramorum inoculum and disease and to conserve tanoak at stand level.

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