scholarly journals Variation in Bark Allocation and Rugosity Across Seven Co-occurring Southeastern US Tree Species

2021 ◽  
Vol 4 ◽  
Author(s):  
Timothy M. Shearman ◽  
J. Morgan Varner

Bark is a complex multifunctional structure of woody plants that varies widely among species. Thick bark is a primary trait that can protect trees from heat generated in surface fires. Outer bark on species that allocate resources to thick bark also tends to be rugose, with bark being thickest at the ridges and thinnest in the furrows. Tree diameter or wood diameter is often used as a predictor for bark thickness but little attention has been made on other factors that might affect bark development and allocation. Here we test multiple mixed effect models to evaluate additional factors (height growth rate, measure height) that correlate with bark allocation and present a method to quantify bark rugosity. We focused on seven co-occurring native tree species in the Tallahatchie Experimental Forest in north Mississippi. Approximately ten saplings of Carya tomentosa, Nyssa sylvatica, Prunus serotina, Pinus echinata, Pinus taeda, Quercus marilandica, and Quercus falcata were destructively sampled for stem analyses. Outer bark thickness (OBT) ranged from 0.01 to 0.77 cm with the thickest maximum outer bark occurring on P. taeda (0.77 cm) and the thinnest maximum outer bark occurring on P. serotina (0.17 cm). Our outer bark allocation models suggest that some individuals with rapid height growth allocate less to outer bark in C. tomentosa, N. sylvatica, P. taeda, and P. serotina, but not for P. echinata or either oak species. All species except for C. tomentosa and N. sylvatica showed evidence for outer bark taper, allocating more outer bark at the base of the bole. Inner bark also was tapered in Carya and the oaks. Bark rugosity varied among species from 0.00 (very smooth) to 0.17 (very rugose) with P. Serotina and C. tomentosa having the smoothest bark. OBT was the best fixed effect for all species. Aside from providing data for several important yet understudied species, our rugosity measures offer promise for incorporating into fluid dynamics fire behavior models.

2020 ◽  
Vol 3 (1) ◽  
pp. 66
Author(s):  
Ferréol Berendt ◽  
Erik Pegel ◽  
Lubomir Blasko ◽  
Tobias Cremer

The wood of Scots pine (Pinus sylvestris L.) shows good properties as building and construction timber but also as furniture or pulp and paper, and thus, is one of the most commercially important European tree species. Scots pine are mostly harvested and processed with a high degree of mechanization. In Northeast Germany (federal states of Brandenburg and Berlin), 36% of harvested Scots pine have a diameter at breast height (DBH) between 7 and 19.9 cm. As a typical industrial wood assortment, a large proportion of the resulting small-sized logs are used in the wood industry to produce boards. Although bark is considered a by-product or waste product of the industry, no actual study has quantified the bark thickness, bark volume, bark mass and bark damage of such Scots pine logs. Therefore, the bark characteristics from 50 logs from 10 different piles were analyzed. Bark volume was quantified using the water displacement method, bark mass by weighing, bark thickness with a precision caliper and bark damage by tape measurements. The diameters of the analyzed 150 log discs were normally distributed and the mean value was 12.9 cm. The results showed average bark damages from 12.0%, which were mostly caused during the felling and processing of logs with the harvester. No significant correlation was found between double bark thickness (mean: 3.0 mm) and the diameter; whereas fresh bark volume (mean: 5.6%) and dry bark mass (mean: 3.3%) were significantly affected by the diameter. As shown for spruce by other authors, bark characteristics may change over time and therefore, should be measured regularly. Moreover, it was shown that bark parameters are site dependent. Thus, quantifying bark characteristics for economically important tree species at both the local and national scale is of great relevance. More detailed analyzes are described by Berendt et al. (2021) [1].


2019 ◽  
Vol 59 (3) ◽  
pp. 535-547 ◽  
Author(s):  
Julieta A Rosell

Abstract Most biological structures carry out multiple functions. Focusing on only one function to make adaptive inferences overlooks that manifold selection pressures and tradeoffs shape the characteristics of a multifunctional structure. Focusing on single functions can only lead to a partial picture of the causes underlying diversity and the evolutionary origin of the structure in question. I illustrate this discussion using bark as a study case. Bark comprises all the tissues surrounding the xylem in woody plants. Broadly, bark includes an inner and mostly living region and an outer, dead one. Of all plant structures, bark has the most complex anatomical structure and ontogenetic origin involving two (and often three) different meristems. Traditionally, the wide diversity in bark traits, mainly bark thickness, has been interpreted as the result of the selective pressures imposed by fire regime. However, recent research has shown that explanations based on fire regime cannot account for salient patterns of bark variation globally including the very strong inner bark thickness–stem diameter scaling, which is likely due to metabolic needs, and the very high intracommunity variation in total, inner, and outer bark thickness, and in inner:outer proportions. Moreover, explanations based on fire disregard that in addition to fire protection, bark carries out several other crucial functions for plants including translocation of photosynthates; storage of starch, soluble sugars, water, and other compounds; protection from herbivores, pathogens, and high temperatures; wound closure, as well as mechanical support, photosynthesis, and likely being involved in xylem embolism repair. All these functions are crucial for plant performance and are involved in synergistic (e.g., storage of water and insulation) and trade-off relationships (e.g., protection from fire vs photosynthetic activity). Focusing on only one of these functions, protection from fire has provided an incomplete picture of the selective forces shaping bark diversity and has severely hindered our incipient understanding of the functional ecology of this crucial region of woody stems. Applying a multifunctional perspective to the study of bark will allow us to address why we observe such high intracommunity variation in bark traits, why some bark trait combinations are ontogenetically impossible or penalized by selection, how bark is coordinated functionally with other plant parts, and as a result, to understand how bark contributes to the vast diversity of plant ecological strategies across the globe.


2021 ◽  
Author(s):  
Kevin M Robertson ◽  
Sharon M Hermann ◽  
Eric L Staller

Abstract Frequently burned old field shortleaf pine (Pinus echinata)–loblolly pine (Pinus taeda) woodlands in the southeastern US provide important wildlife habitat and multiple ecosystem services. Because these communities differ in composition of dominant plant species and have different land use legacies than native pine savannas, the ability to prevent encroachment by off-site broadleaf woody tree species using fire alone is in question. We use a long-term fire experiment to demonstrate that old field pine communities have been prevented from transitioning to hardwood forests for over 50 years through judicious application of prescribed fire applied at 1–2 year intervals, whereas communities with three-year fire intervals show signs of transitioning to hardwood forest. We emphasize tailoring fire regimes to particular contexts of land use history to achieve the most historic and sustainable ecosystem structure and function possible for conservation of native flora and fauna. Study Implications: Demonstrating the ability to maintain natural forest structure of old field loblolly pine–shortleaf pine communities in the southeastern US using frequent prescribed fire has implications for the future sustainability of hundreds of thousands of hectares of such land used to provide critical habitat for many species of imperiled and culturally valued wildlife. It also provides insight into restoration of longleaf pine communities on postagricultural land as promoted by multiple highly funded government initiatives. Frequently burned pine savannas and woodlands are resilient to wildfire and sustain natural hydrological cycles, both important for mitigating the effects of global climate change.


2020 ◽  
Vol 71 (9) ◽  
pp. 2641-2649
Author(s):  
Romain Lehnebach ◽  
Tancrède Alméras ◽  
Bruno Clair

Abstract Recent works revealed that bark is able to produce mechanical stress to control the orientation of young tilted stems. Here we report how the potential performance of this function changes with stem size in six Amazonian species with contrasted bark anatomy. The potential performance of the mechanism depends both on the magnitude of bark stress and the relative thickness of the bark. We measured bark longitudinal residual strain and density, and the allometric relationship between bark thickness and stem radius over a gradient of tree sizes. Constant tensile stress was found in species that rely on bark for the control of stem orientation in young stages. Other species had increasing compressive stress, associated with increasing density attributed to the development of sclereids. Compressive stress was also associated with low relative bark thickness. The relative thickness of bark decreased with size in all species, suggesting that a reorientation mechanism based on bark progressively performs less well as the tree grows. However, greater relative thickness was observed in species with more tensile stress, thereby evidencing that this reduction in performance is mitigated in species that rely on bark for reorientation.


2019 ◽  
Vol 106 (10) ◽  
pp. 1386-1391
Author(s):  
Xiaoxia Li ◽  
Sergio Rossi ◽  
Eryuan Liang
Keyword(s):  

2020 ◽  
Author(s):  
Jin-Hua Qi ◽  
Ze-Xin Fan ◽  
Pei-Li Fu ◽  
Yong-Jiang Zhang ◽  
Frank Sterck

Abstract Growth rate varies across plant species and represents an important ecological strategy for competition, resource use and fitness. However, empirical studies often show a low predictability of functional traits to tree growth. We measured stem diameter and height growth rates of 96 juvenile trees (2 to 5 m tall) of eight evergreen and eight deciduous broadleaf tree species over three consecutive years in a subtropical forest in southwestern China. We examined the relationships between tree growth rates and 20 leaf/stem traits that associated with carbon gain, stem hydraulics and nutrient use efficiency, as well as the difference between evergreen and deciduous trees. We found that cross-species variations of stem diameter/height growth rate can be predicted by leaf photosynthetic capacity, leaf mass per area, xylem theoretical specific hydraulic conductivity, wood density and photosynthetic nutrient use efficiencies. Higher leaf carbon assimilation and lower leaf/stem constructing costs facilitate deciduous species to be more resource acquisitive and consequently faster growth within a relatively shorter growing season, whereas evergreen species exhibit a more conservative strategies and thus slower growth. Further, stem growth rates of evergreen species showed were more dependence on leaf carbon gains, whereas stem hydraulic efficiency were more important for deciduous tree growth. Our results suggest that physiological traits (photosynthesis, hydraulics, nutrient use efficiency) can predict tree diameter and height growth of subtropical tree species. The differential resource acquisition and use strategies and their associations with tree growth between evergreen and deciduous trees provide insights in explaining the co-existence of evergreen and deciduous tree species in subtropical forests.


1996 ◽  
Vol 20 (2) ◽  
pp. 85-89 ◽  
Author(s):  
R. H. Jones ◽  
A. H. Chappelka ◽  
D. H. West

Abstract One-year-old seedlings of 11 commonly used urban shade tree species were protected with plastic shelters to determine effects on survival and growth. Additional seedlings were planted in the cities of Auburn and Opelika, Alabama, to determine seedling performance in actual urban settings and to estimate incidence of vandalism in five urban settings. Shelters increased survival in four species and height growth in seven. Diameter growth responses were mixed. During the first 13 months after planting, only 3% of the seedlings in the cities were damaged by people. However, 20% of the shelters were vandalized at least once. Vandalism rates for shelters were greatest (37-44%) in neighborhoods of privately and publicly owned homes; intermediate (20%) in recreational parks, and lowest (4-6%) in undeveloped or industrial park areas. Installation of each tree with its shelter cost $2.78 (excluding labor) and required 20-25 minutes of labor. Tree shelters show promise as a low-cost alternative to more expensive planting methods, especially in undeveloped portions of cities. South. J. Appl. For. 20(2):85-89.


2020 ◽  
Author(s):  
Yassine Messaoud ◽  
Anya Reid ◽  
Nadezhda M. Tchebakova ◽  
Annika Hofgaard ◽  
Faouzi Messsaoud

Abstract BackgroundThe climate variables effect on tree growth in boreal and temperate forests has received increased interest in the global context of climate change. However, most studies are geographically limited and involved few tree species. Here, sixteen tree species across western North America were used to investigate tree response to climate change at the species range scale. MethodsForest inventory data from 36,944 stands established between 1600 and 1968 throughout western Canada and USA were summarized. Height growth (total height at breast-height age of 50 years) of healthy dominant and co-dominant trees were related to annual and summer temperatures, annual and summer Palmer Drought Severity Index (PDSI, and tree establishment date (ED). Climate-induced height growth patterns were then tested to determine links to spatial environment (soil conditions and geographic locations), species range (coastal, interior, and both ranges) and species traits (shade tolerance and leaf form), using linear mixed model for the global height growth and general linear model to test the height growth patterns for each species. ResultsIncrease of temperatures and PDSI had a positive effect on height growth for most of the study species, whereas Alaska yellow-cedar (Chamaecyparis nootkatensis, (D. Don) Spach) height growth declined with ED. All explaining variables and the interactions explained 59% of the total height growth variance. Although tree height growth response was species-specific, increased height growth during the 20th century was more pronounced for coastal ranged species, high shade tolerant species, and broadleaf species. Furthermore, height growth increase occurred mostly on rich soil, at the northernmost species range, and, unexpectedly, at lower elevations. A decline in height growth for some species further north and especially higher in elevation possibly related to increased cloudiness and precipitation. However, drought conditions remain in interior areas despite moving northward and upward that decrease height growth. ConclusionThese results highlight the general trend (species characteristics and range) and the species-specific height patterns, indicating the spatio-temporal complexity of the growth response to recent global climate change.


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