scholarly journals Spatiotemporal Invasion Severity of Chinese Tallow (Triadica sebifera) and Invasibility of Forest Types in Southern US Forestlands

2021 ◽  
Author(s):  
Sunil Nepal ◽  
W Keith Moser ◽  
Zhaofei Fan
Keyword(s):  
United States ◽  
Forest Type ◽  
Coastal Region ◽  
Pinus Palustris ◽  
The United States ◽  
Slash Pine ◽  
Forest Types ◽  
Triadica Sebifera ◽  
Chinese Tallow ◽  
Severity Class

Abstract Quantifying invasion severity of nonnative invasive plant species is vital for the development of appropriate mitigation and control measures. We examined more than 23,250 Forest Inventory and Analysis (FIA) plots from the southern coastal states of the United States to develop an alternative method to classify and map the invasion severity of Chinese tallow (Triadica sebifera). Remeasured FIA plot-level data were used to examine the spatiotemporal changes in the presence probability and cover percentage of tallow. Four invasion severity classes were identified by using the product of presence probability and cover percentage. Chinese tallow invasion severity increased over time with 90 and 123 counties being classified into the highest severity class for the first and second measurement, respectively. Further, the invasibility of major forest-type groups by severity class was examined using the product of the county-level mean presence probability and mean cover percentage of Chinese tallow as a proxy of invasibility. Longleaf/slash pine (Pinus palustris/P. elliottii) forests were highly resilient to the Chinese tallow invasion. In contrast, elm/ash/cottonwood (Ulmus spp./Fraxinus spp./Populus deltoides) and oak/gum/cypress (Quercus spp./Nyssa spp./Taxodium spp.) forest-type groups were vulnerable to invasion. Study Implications: In the southern United States forestland, differences in invasion severity and vulnerability of forest types to Chinese tallow invasion have been observed across time and space. Our findings provide insight into spatial variations in the severity of Chinese tallow invasion and the relative susceptibility of different forest-type groups in the region to inform monitoring and management of this invasive species. High invasion severity occurs in the lower Gulf of Mexico coastal region of Texas, Louisiana, and Mississippi and the Atlantic coastal region of South Carolina and Georgia, with the longleaf/slash pine and oak/gum/cypress forest-type groups being most susceptible to Chinese tallow invasion. Based on these results, we recommend that management efforts be tailored to the different invasion severity classes. Forests in the high-severity class need a management program coordinated across different agencies and landowners to curb the increase of tallow populations to prevent stand replacing risks. The monitoring of Chinese tallow spread should focus on longleaf/slash pine, loblolly/shortleaf pine, and oak/gum/cypress groups, because the spread rate was higher in these forest-type groups. A better use of scarce resources could be to treat lands in the moderate- and low-severity classes to reduce the propagule pressure levels and post-invasion spread. For those counties with a minimal-severity condition, early detection and eradiction measures should be taken in a timely maner to prevent tallow from invading noninvaded neighboring counties. Managers may be able to treat a larger area of these lands for a given investment compared with lands already severely invaded.

scholarly journals Avian Breeding Season Diversity and Community Composition in Camden White Gum and Slash Pine Plantations

2021 ◽  
Author(s):  
Elizabeth J Messick ◽  
Christopher E Comer ◽  
Michael A Blazier ◽  
T Bently Wigley
Keyword(s):  
United States ◽  
Species Richness ◽  
Community Composition ◽  
Pinus Elliottii ◽  
The United States ◽  
Slash Pine ◽  
Planted Forests ◽  
Eucalyptus Plantation ◽  
Short Rotation Woody Crops ◽  
Eucalyptus Plantations

Abstract In the southern United States, some landowners have established plantations of eucalyptus (Eucalyptus spp.) and are managing them on short rotations (<15 years) to provide wood for fiber and other potential uses. Establishment of short-rotation woody crops dominated by nonnative species has implications for resident fauna in the United States that are largely unknown. We compared avifauna abundance, diversity, and community composition in newly established Camden white gum (Eucalyptus benthamii) plantations with slash pine (Pinus elliottii) plantations of the same age and height (one to two and six to seven years old, respectively) in southwestern Louisiana, USA. Species richness, diversity, and community composition in newly established eucalyptus plantations and six- to seven-year-old pines were similar. More birds were observed, and bird detections varied less in eucalyptus plantations. Indigo buntings (Passerina cyanea) and other shrub-associated species were detected more often in eucalyptus stands. In contrast, species that inhabit herbaceous-dominated communities, such as eastern meadowlarks (Sturnella magna), or that were associated with a dense graminoid community (e.g., Bachman’s sparrow [Peucaea aestivalis]) were detected less often in eucalyptus. Overall, breeding bird communities in eucalyptus plantations one to two years postestablishment differed little from plantations dominated by slash pine. Study Implications Compared with slash pine (Pinus elliottii Englem) plantations of similar age and height (one to two years and six to seven years old, respectively) we found one- to two-year-old eucalyptus (Eucalyptus benthamii Maiden & Cambage) plantations supported similar avian species richness and diversity to six- to seven-year-old pine stands. Furthermore, we found these eucalyptus plantations (E13) supported an avian community that was intermediate to similar aged pine (S13) and pine of similar height (S08). However, avian communities will likely change as eucalyptus plantations age (Christian et al. 1997). Continued monitoring and assessment of community composition, richness, and abundance is important for determining the magnitude of this change. Future investigations focused on nest success, fecundity, postfledging monitoring, and survivorship compared with other types of planted forests and native cover types would help us better understand eucalyptus plantation effects on avifauna demographics (Van Horne 1983, Martin 1998, Jones 2001, Wood et al. 2004, Sage et al. 2006, Riffell et al. 2011).

Characterizing Canopy Openness Across Large Forested Landscapes Using Spherical Densiometer and Smartphone Hemispherical Photography

2021 ◽  
Author(s):  
Katie L Beeles ◽  
Jordon C Tourville ◽  
Martin Dovciak
Keyword(s):  
United States ◽  
Large Range ◽  
Forest Type ◽  
High Elevation ◽  
Canopy Openness ◽  
Hemispherical Photography ◽  
Forest Types ◽  
Northeastern United States ◽  
Closed Canopy ◽  
The Right

Abstract Canopy openness is an important forest characteristic related to understory light environment and productivity. Although many methods exist to estimate canopy openness, comparisons of their performance tend to focus on relatively narrow ranges of canopy conditions and forest types. To address this gap, we compared two popular approaches for estimating canopy openness, traditional spherical densiometer and modern smartphone hemispherical photography, across a large range of canopy conditions (from closed canopy to large gaps) and forest types (from low-elevation broadleaf to high-elevation conifer forests) across four states in the northeastern United States. We took 988 field canopy openness measurements (494 per instrument) and compared them across canopy conditions using linear regression and t-tests. The extensive replication allowed us to quantify differences between the methods that may otherwise go unnoticed. Relative to the densiometer, smartphone photography overestimated low canopy openness (<10%) but it underestimated higher canopy openness (>10%), regardless of forest type. Study Implications We compared two popular ways of measuring canopy openness (smartphone hemispherical photography and spherical densiometer) across a large range of forest structures encountered in the northeastern United States. We found that, when carefully applied, the traditional spherical densiometer can characterize canopy openness across diverse canopy conditions (including closed canopies) as effectively as modern smartphone canopy photography. Although smartphone photography reduced field measurement time and complexity, it was more susceptible to weather than the densiometer. Although selection of the right method depends on study objectives, we provide a calibration for these two popular methods across diverse canopies.

scholarly journals Understory Vegetation Richness and Diversity of Eucalyptus benthamii and Pinus elliottii Plantations in the Midsouth US

2019 ◽  
Author(s):  
Andrea De Stefano ◽  
Michael A Blazier ◽  
Christopher E Comer ◽  
Thomas J Dean ◽  
T Bently Wigley
Keyword(s):  
United States ◽  
Species Richness ◽  
Soil Ph ◽  
Pinus Elliottii ◽  
The United States ◽  
Slash Pine ◽  
Understory Vegetation ◽  
Understory Species ◽  
Species Richness And Diversity ◽  
The Impact

Abstract In the Western Gulf region of the United States cold-tolerant eucalyptus have been explored as pulpwood feedstock. However, non-native plantations may alter understory species diversity, modifying environmental conditions and soil characteristics. Few studies have compared eucalyptus plantations with native ecosystems to understand the impact on understory vegetation in the United States. In this study, we compared understory plant species richness and diversity during 2014–2016 in (1) slash pine (Pinus elliottii) established in 2008, (2) slash pine established in 2013, and (3) and Camden white gum (Eucalyptus benthamii) established in 2013. Overstory characteristics, soil pH, and soil nutrient concentrations were measured to understand factors that affected understory species richness and diversity. Results indicated a decline in understory species richness over time, with Camden white gum in an intermediate condition between same-age slash pine (highest richness) and older slash pine (lowest richness). Leaf area index, soil pH and K, and tree height were the most important factors influencing understory species richness and diversity. The adoption of fast-growing eucalyptus on these sites will probably accelerate the deterioration of natural habitats and reduce open-condition species in favor of shade-tolerant species, overturning the conservation efforts already put in place by governmental agencies and conservation groups.

scholarly journals Differences in seed properties and germination between native and introduced populations of Triadica sebifera

2019 ◽  
Vol 13 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Jialiang Zhang ◽  
Evan Siemann ◽  
Baoliang Tian ◽  
Wei Huang ◽  
Jianqing Ding
Keyword(s):  
United States ◽  
Seed Germination ◽  
Soluble Protein ◽  
Native Species ◽  
Seed Mass ◽  
The United States ◽  
Invasion Success ◽  
Native Range ◽  
Triadica Sebifera ◽  
Introduced Range

Abstract Aims Seeds of many invasive plants germinate more quickly than those of native species, likely facilitating invasion success. Assessing the germination traits and seed properties simultaneously for introduced and native populations of an invasive plant is essential to understanding biological invasions. Here, we used Triadica sebifera as a study organism to examine intraspecific differences in seed germination together with seed characteristics. Methods We measured physical (volume, mass, coat hardness and coat thickness of seeds) and chemical (crude fat, soluble protein, sugar, gibberellins [GA] and abscisic acid [ABA] of kernels) properties of T. sebifera seeds collected in 2017 from 12 introduced (United States) populations and 12 native (China) populations and tested their germination rates and timing in a greenhouse experiment in China. Furthermore, we conducted an extra experiment in the United States using seeds collected in 2016 and 2017 to compare the effects of study sites (China vs. United States) and seed collection time (2016 vs. 2017) on seed germination. Important Findings Seeds from the introduced range germinated faster than those from the native range. Physical and chemical measurements showed that seeds from the introduced range were larger, had higher GA concentrations and GA:ABA ratio, but lower crude fat concentrations compared to those from the native range. There were no significant differences in seed mass, coat hardness and coat thickness or kernel ABA, soluble protein or sugar concentrations between seeds from introduced vs. native ranges. Germination rates were correlated between United States and China greenhouses but germination rates for populations varied between collection years. Our results suggest that larger seeds and higher GA likely contribute to faster germination, potentially facilitating T. sebifera invasion in the introduced range.

scholarly journals Using Forest Inventory Data with Landsat 8 Imagery to Map Longleaf Pine Forest Characteristics in Georgia, USA

2019 ◽  
Vol 11 (15) ◽  
pp. 1803 ◽  
Author(s):  
John Hogland ◽  
Nathaniel Anderson ◽  
David L. R. Affleck ◽  
Joseph St. Peter
Keyword(s):  
United States ◽  
Forest Inventory ◽  
Forest Type ◽  
Longleaf Pine ◽  
Basal Area ◽  
Pinus Palustris ◽  
Machine Learning Algorithms ◽  
Landsat 8 ◽  
Inventory Data ◽  
Forest Inventory Data

This study improved on previous efforts to map longleaf pine (Pinus palustris) over large areas in the southeastern United States of America by developing new methods that integrate forest inventory data, aerial photography and Landsat 8 imagery to model forest characteristics. Spatial, statistical and machine learning algorithms were used to relate United States Forest Service Forest Inventory and Analysis (FIA) field plot data to relatively normalized Landsat 8 imagery based texture. Modeling algorithms employed include softmax neural networks and multiple hurdle models that combine softmax neural network predictions with linear regression models to estimate key forest characteristics across 2.3 million ha in Georgia, USA. Forest metrics include forest type, basal area and stand density. Results show strong relationships between Landsat 8 imagery based texture and field data (map accuracy > 0.80; square root basal area per ha residual standard errors < 1; natural log transformed trees per ha < 1.081). Model estimates depicting spatially explicit, fine resolution raster surfaces of forest characteristics for multiple coniferous and deciduous species across the study area were created and made available to the public in an online raster database. These products can be integrated with existing tabular, vector and raster databases already being used to guide longleaf pine conservation and restoration in the region.

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