scholarly journals When a foundation crumbles: forecasting forest community dynamics following the decline of the foundation speciesTsuga canadensis

2017 ◽  
Author(s):  
Bradley S. Case ◽  
Hannah L. Buckley ◽  
Audrey A. Barker-Plotkin ◽  
David A. Orwig ◽  
Aaron M. Ellison
Keyword(s):  
Tree Species ◽  
Community Dynamics ◽  
Initial Conditions ◽  
Basal Area ◽  
Adelges Tsugae ◽  
Eastern Hemlock ◽  
Forest Community ◽  
Forest Communities ◽  
Salvage Logging ◽  
Hemlock Decline

AbstractIn the forests of northeastern North America, invasive insects and pathogens are causing major declines in some tree species and a subsequent reorganization of associated forest communities. Using observations and experiments to investigate the consequences of such declines are hampered because trees are long-lived. Simulation models can provide a means to forecast possible futures based on different scenarios of tree species decline, death, and removal. Such modeling is particularly urgent for species such as eastern hemlock (Tsuga canadensis), a foundation species in many northeast forest regions that is declining due to the hemlock woolly adelgid (Adelges tsugae). Here, we used an individual-based forest simulator, SORTIE-ND, to forecast changes in forest communities in central Massachusetts over the next 200 years under a range of scenarios: a no-adelgid, status-quo scenario; partial resistance of hemlock to the adelgid; adelgid irruption and total hemlock decline over 25 years, adelgid irruption and salvage logging of hemlock trees; and two scenarios of preemptive logging of hemlock and hemlock/white pine.We applied the model to six study plots comprising a range of initial species mixtures, abundances, and levels of hemlock dominance. Simulations indicated that eastern white pine, and to a lesser extent black birch and American beech, would gain most in relative abundance and basal area following hemlock decline. The relative dominance of these species depended on initial conditions and the amount of hemlock mortality, and their combined effect on neighborhood-scale community dynamics. Simulated outcomes were little different whether hemlock died out gradually due to the adelgid or disappeared rapidly following logging. However, if eastern hemlock were to become partially resistant to the adelgid, hemlock would be able to retain its dominance despite substantial losses of basal area. Our modeling highlights the complexities associated with secondary forest succession due to ongoing hemlock decline and loss. We emphasize the need both for a precautionary approach in deciding between management intervention or simply doing nothing in these declining hemlock forests, and for clear aims and understanding regarding desired community- and ecosystem-level outcomes.

scholarly journals Vegetation Analysis of Namuna Community Forest of Salbari, Sanischare VDC in Jhapa District, Eastern Nepal

2009 ◽  
Vol 23 ◽  
pp. 12-15
Author(s):  
Krishna Prasad Bhattarai
Keyword(s):  
Tree Species ◽  
Forest Conservation ◽  
Basal Area ◽  
Mean Value ◽  
Forest Community ◽  
Total Density ◽  
Community Forest ◽  
History Museum ◽  
Shorea Robusta ◽  
Vegetation Study

Vegetation study was carried out in an afforested land called Namuna Community Forest in Salbari, Sanischare, VDC, Jhapa, District. Random samplings for estimation of density, frequency, basal area and IVI were carried out by laying quadrates (10m x 10 m) at different sites of forest, three times and mean value was calculated. Nine tree species were recorded during field study. Total density of 10,410 pl/ha and total basal area of 33.956 m2/ha of tree species were recorded. The value of density (1790 pl/ha), basal area (31.45m2/ha) and IVI (130.63) were found highest for Shorea robusta, which is ecologically successful species in this forest. Lower value of basal area showed that this forest is young and regenerating. Other tree species had comparatively lower value of density, basal area and IVI due to regular human inte rference. Therefore an example of establishing forest community so as to initiate the conservation of local biodiversity has been discussed in this article.Key words: Community forest; conservation; IVI estimation; regenerating; Shorea robustaJournal of Natural History Museum Vol. 23, 2008 Page 12-15

Canopy tree growth responses following selection harvest in seven species varying in shade tolerance

2009 ◽  
Vol 39 (2) ◽  
pp. 430-440 ◽  
Author(s):  
Trevor A. Jones ◽  
Grant M. Domke ◽  
Sean C. Thomas
Keyword(s):  
Community Dynamics ◽  
Time Lag ◽  
Species Abundance ◽  
Basal Area ◽  
Maximum Growth ◽  
Forest Community ◽  
Growth Responses ◽  
Canopy Tree ◽  
Tolerant Species ◽  
Shade Tolerant Species

We used tree ring measurements to investigate the temporal response of basal area increment (BAI) of canopy trees following selection harvests by sampling across a chronosequence of stands with known harvest dates in tolerant hardwood (Great Lakes – St. Lawrence) stands in central Ontario. Seven tree species of various shade tolerances ranged widely in their responses to reduced competition. The more shade-tolerant species responded more positively: shade-tolerant species showed an average increase in BAI of 35% 4–15 years postharvest compared with 16% for mid-tolerant species and –7.5% for intolerant species. All species showed a time-lag in postharvest growth responses, with maximum growth responses occurring between 3 and 15 years postharvest. Tree size was the most important factor determining the magnitude of BAI response, with smaller trees consistently responding more than larger trees. We suggest that higher growth responses to selection harvests among shade-tolerant species may contribute to declines in mid-tolerant species abundance in selection-managed stands. More broadly, interspecific variability in canopy tree responses to forest disturbance appears to follow patterns distinct from seedling and sapling responses, with important implications to forest community dynamics in both managed and unmanaged forests.

scholarly journals Vegetation and ecoregion analysis at Sipirok Botanic Gardens, South Tapanuli, North Sumatra, Indonesia

2020 ◽  
Vol 21 (6) ◽  
Author(s):  
Mustaid Siregar ◽  
DANANG W. PURNOMO ◽  
HARTUTININGSIH M-SIREGAR ◽  
JOKO RIDHO WITONO
Keyword(s):  
Plant Species ◽  
Tree Species ◽  
Secondary Forest ◽  
Natural Forest ◽  
Forest Community ◽  
Ex Situ ◽  
Forest Communities ◽  
Botanic Gardens ◽  
Remnant Forest ◽  
North Sumatra

Abstract. Siregar M, Purnomo DW, Siregar HM, Witono JR. 2020. Vegetation and ecoregion analysis at Sipirok Botanic Gardens, South Tapanuli, North Sumatra, Indonesia. Biodiversitas 21: 2526-2535. Botanic Gardens is an ex-situ plant conservation area. Enrichment of plant collections of Botanic Gardens in Indonesia is based on ecoregion types. To find out the type of ecoregion, the existing vegetation, main native species should be known. The research aimed to analyze the existing vegetation and ecoregion type at Sipirok Botanic Gardens. Existing vegetation has been carried out using a separate plot method 20x20 m which is placed on purposively in nine locations considered to have different vegetation types, namely remnant forest, young secondary forests and shrubs, rubber plantation, and grasslands. Around 66 species belonged to 45 genera and 27 families were found in vascular plants (dbh ≥ 10 cm). There were 66 species of sapling belonged to 54 genera and 35 families, and 110 seedlings belonged to 87 genera and 50 families. The tree species that have the highest Importance Value Index are Ficus sumatrana (PU-1), Myristica fatua (PU-3), Hevea brasiliensis (PU-4 and PU-7), Artocarpus elasticus (PU-8), and Knema cinerea (PU-9). No trees were found in young secondary forest/shrub plots and grasslands. Unlike the species dominance index, the species diversity index and species equitability index are higher in natural forest plots. Beta diversity based on Jaccard similarity index and Whittaker's index shows a relatively different species composition among plots. Cluster analysis shows the tendency of grouping in 2 types of communities, namely: a) remnant forest communities, and b) secondary communities. The natural forest community is further divided into two communities consisting of remnant forest tree species and industrial/plantation plant species also secondary tree species. Secondary communities are also further divided into secondary forest communities and grasslands. Based on ecoregion analysis using previous publications, altitude, and diversity of plant species in the study site, Sipirok Botanic Gardens is a transitional zone of the Sumatran lowland rainforest and mountain rainforest.

Tree canopy displacement and neighborhood interactions

2003 ◽  
Vol 33 (7) ◽  
pp. 1323-1330 ◽  
Author(s):  
Christine C Muth ◽  
F A Bazzaz
Keyword(s):  
Community Dynamics ◽  
Basal Area ◽  
Tree Canopy ◽  
Forest Community ◽  
Spatial Proximity ◽  
Forest Plot ◽  
High Resource ◽  
Canopy Position ◽  
Canopy Area ◽  
Canopy Depth

Competitive interactions among plants are largely determined by spatial proximity. However, despite their sessile nature, plants have the ability to avoid neighbors by growing towards areas with high resource availability and reduced competition. Because of this flexibility, tree canopies are rarely centered directly above their stem bases and are often displaced. We sought to determine how a tree's competitive neighborhood influences its canopy position. In a 0.6-ha temperate forest plot, all trees greater than 10 cm DBH (n = 225) were measured for basal area, height, canopy depth, and trunk position. Canopy extent relative to trunk base was determined in eight subcardinal directions, and this information was used to reconstruct canopy size, shape, and position. We found that trees positioned their canopies away from large neighbors, close neighbors, and shade-tolerant neighbors. Neighbor size, expressed as basal area or canopy area, was the best indication of a neighbor's importance in determining target tree canopy position. As neighborhood asymmetry increased, the magnitude of canopy displacement increased, and the precision with which canopies avoided neighbors increased. Flexibility in canopy shape and position appears to reduce competition between neighbors, thereby influencing forest community dynamics.

scholarly journals Composition and Specialization of the Lichen Functional Traits in a Primeval Forest—Does Ecosystem Organization Level Matter?

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 485
Author(s):  
Anna Łubek ◽  
Martin Kukwa ◽  
Bogdan Jaroszewicz ◽  
Patryk Czortek
Keyword(s):  
Functional Traits ◽  
Asexual Reproduction ◽  
Community Assembly ◽  
Tree Species ◽  
Functional Trait ◽  
Forest Community ◽  
Forest Communities ◽  
Niche Diversity ◽  
Dark Pigmentation ◽  
Ecosystem Organization

Current trends emphasize the importance of the examination of the functional composition of lichens, which may provide information on the species realized niche diversity and community assembly processes, thus enabling one to understand the specific adaptations of lichens and their interaction with the environment. We analyzed the distribution and specialization of diverse morphological, anatomical and chemical (lichen secondary metabolites) traits in lichen communities in a close-to-natural forest of lowland Europe. We considered these traits in relation to three levels of forest ecosystem organization: forest communities, phorophyte species and substrates, in order to recognize the specialization of functional traits to different levels of the forest complexity. Traits related to the sexual reproduction of mycobionts (i.e., ascomata types: lecanoroid apothecia, lecideoid apothecia, arthonioid apothecia, lirellate apothecia, stalked apothecia and perithecia) and asexual reproduction of mycobionts (pycnidia, hyphophores and sporodochia) demonstrated the highest specialization to type of substrate, tree species and forest community. Thallus type (foliose, fruticose, crustose and leprose thalli), ascospore dark pigmentation and asexual reproduction by lichenized diaspores (soredia and isidia) revealed the lowest specialization to tree species and substrate, as well as to forest community. Results indicate that lichen functional trait assemblage distribution should not only be considered at the level of differences in the internal structure of the analyzed forest communities (e.g., higher number of diverse substrates or tree species) but also studied in relation to specific habitat conditions (insolation, moisture, temperature, eutrophication) that are characteristic of a particular forest community. Our work contributes to the understanding of the role of the forest structure in shaping lichen functional trait composition, as well as enhancing our knowledge on community assembly rules of lichen species.

A rules-based approach for predicting the eastern hemlock component of forests in the northeastern United States

2009 ◽  
Vol 39 (8) ◽  
pp. 1453-1464 ◽  
Author(s):  
Jarrod S. Doucette ◽  
William M. Stiteler ◽  
Lindi J. Quackenbush ◽  
Jeffrey T. Walton
Keyword(s):  
New York ◽  
Forest Cover ◽  
Reference Model ◽  
Basal Area ◽  
Field Measurements ◽  
Adelges Tsugae ◽  
Eastern Hemlock ◽  
Slope Aspect ◽  
Landsat Images ◽  
Environmental Indices

The expanding threat of hemlock woolly adelgid (Adelges tsugae Annand) infestation has generated interest in locating eastern hemlock ( Tsuga canadensis (L.) Carr.). Prior studies have incorporated remotely sensed imagery to detect eastern hemlock presence or absence. The goal of this study was to develop methodology to quantify hemlock abundance using software and data accessible to forest managers. Three seasons of Landsat ETM+ scenes served as the imagery basis, whereas simple (slope, aspect, and curvature) and detailed (heat and wetness) environmental indices were extracted from a digital elevation model. Three hundred and forty-nine forest plots representing the typical forest cover found in the Catskill Mountain Region, New York, served as ground reference; model input used the percentage of hemlock basal area for each plot. The models generally underpredicted in plots with substantial hemlock composition, whereas overpredictions mainly occurred in mixed forests that lacked hemlock. Underpredictions negated overpredictions in mixed hemlock deciduous forests resulting in a neutral model. Correlation coefficients ranged from a high of 0.67 for the model created from three Landsat images to a low of 0.01 for the heat and wetness indices model. Although the models were typically within 10% of field measurements, there was no overall benefit in including topographic indices for mapping hemlock abundance.

scholarly journals Eastern Hemlock Decline in Riparian Areas from Maine to Alabama

2011 ◽  
Vol 28 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Daniel M. Evans ◽  
W. Michael Aust ◽  
C. Andrew Dolloff ◽  
Ben S. Templeton ◽  
John A. Peterson
Keyword(s):  
New England ◽  
Hemlock Woolly Adelgid ◽  
Adelges Tsugae ◽  
Ecosystem Dynamics ◽  
Eastern Hemlock ◽  
Forest Composition ◽  
Mountain Range ◽  
Riparian Areas ◽  
Conifer Species ◽  
Hemlock Decline

Abstract Eastern hemlock (Tsuga canadensis) in the Appalachian mountain range is threatened by the introduced hemlock woolly adelgid (Adelges tsugae). Potential impacts on riparian systems are great because of eastern hemlock's role as a foundation species that influences site soil, vegetation, and stream characteristics. We installed permanent research sites at 49 locations in riparian areas, from Maine to Alabama, to survey eastern hemlock health, measure stand dynamics, and predict near-term forest composition without eastern hemlock. This report summarizes the initial stand measurements from summer of 2008. We found hemlock woolly adelgid present at 25 of 49 stands from Massachusetts to Georgia, and all of these stands had some degree of hemlock decline. New England states, Ohio, western Pennsylvania, Kentucky, and Alabama had good hemlock health and no sign of hemlock woolly adelgid. Eighteen of the 49 sites had no nonhemlock conifer species in the overstory, and 30 of 49 sites had less than 5 m2 ha−1 of nonhemlock conifers. Without eastern hemlock, 25 of the stands would have more than 90% hardwood in the overstory, many of which are in the mid-Atlantic and southern states at sites dominated by shrubs in the understory such as Rhododendron maximum. Competition from shrubs may hinder stand regeneration after disturbance by hemlock woolly adelgid. On the basis of the abundance of hardwood species and lack of conifer species present in the overstory at many infested hemlock-dominated stands, these sites may convert to hardwood-dominated stands, which will affect terrestrial and aquatic ecosystem dynamics.

Spatial patterns of tropical forest trees in Western Polynesia suggest recruitment limitations during secondary succession

2007 ◽  
Vol 23 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Janet Franklin ◽  
Sergio J. Rey
Keyword(s):  
Tree Species ◽  
Secondary Succession ◽  
Community Dynamics ◽  
Secondary Forest ◽  
Abiotic Factors ◽  
Natural Disturbance ◽  
Forest Community ◽  
Primary Forest ◽  
Tolerant Species ◽  
Shade Tolerant Species

Spatial analysis can be used to relate the patterns of tree species to their regeneration syndromes – pioneer to late-successional – and is a first step in refining hypotheses about the species traits and biotic and abiotic factors that give rise to forest community dynamics. This study examines the spatial pattern of the most abundant trees in three 0.45-ha plots in species-poor lowland rain forests on oceanic islands in Tonga, Western Polynesia, that experience frequent natural disturbance and have a 3000-y history of shifting cultivation. We contrast secondary vs. remnant late-successional forest, with particular attention paid to the spatial dispersion and clustering of tree species, and the presence of spatial dependence in the density of seedlings and saplings. Shade-tolerant species were not strongly clustered at any scale. They did not appear to be dispersal limited, in late successional forest, and only some showed patterns consistent with density-dependent mortality (more clumped when small). Shade-tolerant species were more clumped in secondary forest, and may be dispersal-limited there because vertebrate dispersers prefer primary forest. Shade-intolerant species were clumped in gaps in late-successional forest, but some were also clumped in secondary forest, indicating that they too may be dispersal limited during secondary succession. We also compared the species composition of seedlings and saplings in the centre of plots with trees in the surrounding area and inferred that active dispersal (by vertebrate frugivores) contributed as much as 50% to site species richness.

scholarly journals Species Diversity, Forest Community Structure and Regeneration in Banke National Park

2016 ◽  
Vol 16 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Renu Napit
Keyword(s):  
Community Structure ◽  
Species Diversity ◽  
Tree Species ◽  
National Park ◽  
Basal Area ◽  
Size Class ◽  
Forest Community ◽  
Total Density ◽  
Size Class Distribution ◽  
Class Distribution

Banke national park, located in Banke district of western Nepal with an area of 550 sq. km was established as the  tenth national park in 2010 A.D. Forest community structure, species diversity and natural regeneration were  studied in the Park. A total of 1067 plots at every interval of 200m were laid by line transect method for the study. In  each plot three concentric rings of radii of 10m, 5m, and 1m were laid down for the study of trees, shrubs/saplings  and herbs/seedlings respectively. The park was floristically rich with a total of 113 species of trees representing 57  genera and 28 families. Similarly 85 species of shrubs including climbers and 107 species of herbs including  herbaceous climbers, and grasses were recorded. The obtained results from the size class distribution of the trees  resembling inverse ‘J’ shape indicated the good regenerating capability of the forest in the park. Fifty eight species  of saplings and 40 species of seedlings of trees were recorded. From the quantitative study of the trees, the  dominant species was Shorea robusta based on IVI (important value index) values, which was followed by Terminalia  alata, Anogeissus latifolius, Mallotus philippinensis, etc. The total density stand (D) and basal area (BA) of the  park were 291.48 trees/ha and 21.13 m2/ha respectively. The highest density (D) and the basal area (BA) of S.  robusta was 46.07 trees /ha and 5.07m2/ha respectively. The species diversity index (H) of the tree species in BaNP  was 1.32, with species evenness (J) of 0.64 and index of dominance (C) of 0.08. A total of seven forest community  types were estimated in the Park. The size class distribution diagram of all trees showed right skewed (inverse J  shaped) pattern indicating a good regenerating capability of the forest. The regeneration of S. robusta, T. alata and  A. latifolius were higher in comparison to other tree species which was indicated by the higher seedlings and  saplings density of them. S. robusta was the dominant with saplings density of 200.49 / ha and seedlings density  of 27153.4 /ha.Nepal Journal of Science and Technology Vol. 16, No.1 (2015) pp. 17-30

Floristic Variation of Tree Communities and Their Association with Soil Properties in Pulau Jerejak, Penang, Peninsular Malaysia

2020 ◽  
Vol 14 (1) ◽  
pp. 34
Author(s):  
Faezah Pardi
Keyword(s):  
Tree Species ◽  
Diversity Index ◽  
Basal Area ◽  
Peninsular Malaysia ◽  
Importance Value ◽  
Conservation Action ◽  
Endangered Tree ◽  
Endangered Tree Species ◽  
Tree Communities ◽  
Floristic Variation

This study was conducted at Pulau Jerejak, Penang to determine the floristic variation of its tree communities. A 0.5-hectare study plot was established and divided into 11 subplots. A total of 587 trees with diameter at breast height (DBH) of 5 cm and above were measured, identified and recorded. The tree communities comprised of 84 species, 63 genera and 32 families. The Myrtaceae was the most speciose family with 10 recorded species while Syzgium glaucum (Myrtaceae) was the most frequent species. The Myrtaceae recorded the highest density of 306 individuals while Syzgium glaucum (Myrtaceae) had the highest species density of 182 individuals. Total tree basal area (BA) was 21.47 m2/ha and family with the highest BA was Myrtaceae with 5.81 m2/ha while at species level, Syzgium glaucum (Myrtaceae) was the species with the highest total BA in the plot with value of 4.95 m2/ha. The Shannon˗Weiner Diversity Index of tree communities showed a value of 3.60 (H'max = 4.43) and Evenness Index of 0.81 which indicates high uniformity of tree species. The Margalef Richness Index (R') revealed that the tree species richness was 13.02. Myrtaceae had the highest Importance Value of 20.4%. The Canonical Correspondence Analysis (CCA) showed that Diospyros buxifolia (Ebenaceae) and Pouteria malaccensis (Sapotaceae) were strongly correlated to low pH. Dysoxylum cauliflorum (Meliaceae) and Eriobotrya bengalensis (Rosaceae) were correlated to phosphorus (P) and calcium ion (Ca2+), respectively. Therefore, the trees species composition at Pulau Jerejak showed that the biodiversity is high and conservation action should be implemented to protect endangered tree species. Keywords: Floristic variation; Tree communities; Trees composition; Pulau Jerejak; Species diversity

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