Plant size, environmental factors and functional traits jointly shape the stem radius growth rate in an evergreen coniferous species across ontogenetic stages

2020 ◽  
Author(s):  
Zhili Liu ◽  
Kouki Hikosaka ◽  
Fengri Li ◽  
Liangjun Zhu ◽  
Guangze Jin

Abstract Aims Plant size, environmental conditions and functional traits are important for plant growth; however, it is less clear which combination of these factors is the most effective for predicting tree growth across ontogenetic stages. Methods We selected 65 individuals of an evergreen coniferous species, Pinus koraiensis, with diameters at breast height (DBH) from 0.3 to 100 cm in Northeast China. For each individual, we measured the stem radius growth rate (SRGR, μm/year) for the current year, environmental factors (light, soil nutrients and water) and functional traits (leaf, branch and root traits). Important Findings SRGR increased with DBH when the DBH was lower than 58 cm, whereas it decreased with DBH when the DBH was larger than 58 cm. Structural equation modeling analysis suggested that , when the DBH was 0-15 cm, plant size had a direct negative influence on SRGR and an indirect positive influence on SRGR due to the light intensity above the plant. Plant size had direct positive and negative effects when the DBH was 16-58 cm and 59-100 cm, respectively. When the DBH was larger than 15 cm, soil parameters were more important than light intensity for SRGR. The functional traits selected for use in the best model were changed from the specific leaf area and wood density to the root nitrogen concentration with increasing tree size. In summary, plant size, environmental factors and functional traits jointly shaped tree growth, and their relative influence varied with size, suggesting that the resources limiting tree growth may change from light to soil nutrients with increasing tree size.


Author(s):  
Zhuo-Dong Jiang ◽  
Phillip R. Owens ◽  
Amanda J. Ashworth ◽  
Bryan A. Fuentes ◽  
Andrew L. Thomas ◽  
...  

AbstractAgroforestry systems play an important role in sustainable agroecosystems. However, accurately and adequately quantifying the relationships between environmental factors and tree growth in these systems are still lacking. Objectives of this study were to quantify environmental factors affecting growth of four tree species and to develop functional soil maps (FSM) for each species in an agroforestry site. The diameter at breast height, absolute growth rate (AGR), and neighborhood competition index of 259 trees from four species (northern red oak [Quercus rubra], pecan [Carya illinoinensis], cottonwood [Populus deltoides], and sycamore [Platanus occidentalis]) were determined. A total of 51 topsoil samples were collected and analyzed, and 12 terrain attributes were derived from the digital elevation model. The relationships between AGR, soil, topography, and tree size were analyzed using Spearman correlation. Based on correlation analysis, FSM for each species were generated using the k-means cluster method by overlaying correlated soil and terrain attribute maps. Results showed tree size and terrain attributes were driving factors affecting tree growth rate relative to soil properties. The spatial variations in AGR among functional units were statistically compared within tree species and the areas with larger AGR were identified by the FSM. This study demonstrated that FSM could delineate areas with different AGR for the oak, cottonwood, and sycamore trees. The AGR of pecan trees did not vary among functional units. The generated FSM may allow land managers to more precisely establish and manage agroforestry systems.



2021 ◽  
Vol 483 ◽  
pp. 118908
Author(s):  
Mizanur Rahman ◽  
Masum Billah ◽  
Md Obydur Rahman ◽  
Debit Datta ◽  
Muhammad Ahsanuzzaman ◽  
...  


2005 ◽  
Vol 35 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Peter H Wyckoff ◽  
James S Clark

We address the relationships between tree growth rate and growing environment for 21 co-occurring species. Tree growth rates are obtained from mapped plots at the Coweeta Long-Term Ecological Research site in the southern Appalachian Mountains. We employ high-resolution aerial photography to assess the light environment for trees growing in these plots, using exposed crown area (ECA) as a surrogate for light interception. The relationship between growth and ECA is compared with two other growth predictors: tree size and shade-tolerance classification. We find that ECA is an excellent predictor of tree growth (average R2 = 0.69 for nine species). When ECA is combined with tree size, growth rate prediction is improved (average R2 = 0.76). Tree size alone is also a strong predictor of tree growth (average R2 = 0.68). Shade-tolerance classification, by contrast, is a poor predictor of tree growth.



2012 ◽  
Vol 42 (11) ◽  
pp. 1983-1995 ◽  
Author(s):  
Adrian Das

Tree growth and competition play central roles in forest dynamics. Yet models of competition often neglect important variation in species-specific responses. Furthermore, functions used to model changes in growth rate with size do not always allow for potential complexity. Using a large data set from old-growth forests in California, models were parameterized relating growth rate to tree size and competition for four common species. Several functions relating growth rate to size were tested. Competition models included parameters for tree size, competitor size, and competitor distance. Competitive strength was allowed to vary by species. The best ranked models (using Akaike’s information criterion) explained between 18% and 40% of the variance in growth rate, with each species showing a strong response to competition. Models indicated that relationships between competition and growth varied substantially among species. The results also suggested that the relationship between growth rate and tree size can be complex and that how we model it can affect not only our ability to detect that complexity but also whether we obtain misleading results. In this case, for three of four species, the best model captured an apparent and unexpected decline in potential growth rate for the smallest trees in the data set.



2016 ◽  
Author(s):  
Daniel S. Falster ◽  
Remko A. Duursma ◽  
Richard G. FitzJohn

AbstractPlant species differ in many functional traits that drive differences in rates of photosynthesis, biomass allocation, and tissue turnover. Yet, it remains unclear how – and even if – such traits influence whole-plant growth, with the simple linear relationships predicted by existing theory often lacking empirical support. Here we present a new theoretical framework for understanding the effect of diverse functional traits on plant growth and shade-tolerance, extending a widely-used theoretical model that links growth rate in seedlings with a single leaf trait to explicitly include influences of size, light environment, and five other prominent traits: seed mass, height at maturation, leaf mass per unit leaf area, leaf nitrogen per unit leaf area, and wood density. Based on biomass production and allocation, this framework explains why the influence of prominent traits on growth rate and shade tolerance often varies with plant size and why the impact of size on growth varies among traits. Considering growth rate in height, we find the influence of: i) leaf mass per unit leaf area is strong in small plants but weakens with size, ii) leaf nitrogen per unit leaf area does not change with size, iii) wood density is present across sizes but is strongest at intermediate sizes, iv) height at maturation strengthens with size, and v) seed mass decreases with size. Moreover, we show how traits moderate plant responses to light environment and also determine shade tolerance, supporting diverse empirical results. By disentangling the effects of plant size, light environment and traits on growth rates, our results provide a solid theoretical foundation for trait ecology and thus provide a platform for understanding growth across diverse species around the world.



2016 ◽  
Vol 104 (5) ◽  
pp. 1488-1503 ◽  
Author(s):  
Anaïs Gibert ◽  
Emma F. Gray ◽  
Mark Westoby ◽  
Ian J. Wright ◽  
Daniel S. Falster


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 449f-450
Author(s):  
Lisa M. Barry ◽  
Michael N. Dana

Legumes are grown as nurse crops in agriculture because they increase soil microbial life and productivity. Native legumes have potential in ecological restoration to mimic the benefits found in agriculture plus they enhance the restored ecosystem. This study was initiated to compare the growth rates, nodulation characteristics, and nitrogen fixation rates of a native versus a non-native legume. The two legumes were partridge pea (Cassia fasciculata); a native, wild, annual legume and soybean (Glycine max `Century Yellow); a domesticated, agricultural, annual legume native to Asia. Plants were grown for 11 weeks in pots containing silica sand and received a nitrogen-free Hoagland's nutrient solution. Beginning at week 12, plants were harvested weekly for four consecutive weeks. Nodulated root systems were exposed to acetylene gas and the resulting ethylene amounts were measured. The two legumes exhibited significant differences in nodule size and shape and plant growth rate. In soybean, nodules were large, spherical, and clustered around the taproot while in partridge pea, nodules were small, irregularly shaped, and spread throughout the fibrous root system. Soybean plants had a significantly faster growth rate at the onset of the experiment but partridge pea maintained a constant growth rate and eventually exceeded soybean plant size. In spite of these observed differences, partridge pea and soybean plants were equally efficient at reducing acetylene to ethylene. These results indicate partridge pea has the potential to produce as much nitrogen in the field as soybean. Native legumes such as partridge pea deserve further research to explore their use as nurse crops in agricultural or restoration regimes.





Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 31 ◽  
Author(s):  
Maria N. Metsoviti ◽  
George Papapolymerou ◽  
Ioannis T. Karapanagiotidis ◽  
Nikolaos Katsoulas

In this research, the effect of solar irradiance on Chlorella vulgaris cultivated in open bioreactors under greenhouse conditions was investigated, as well as of ratio of light intensity in the 420–520 nm range to light in the 580–680 nm range (I420–520/I580–680) and of artificial irradiation provided by red and white LED lamps in a closed flat plate laboratory bioreactor on the growth rate and composition. The increase in solar irradiance led to faster growth rates (μexp) of C. vulgaris under both environmental conditions studied in the greenhouse (in June up to 0.33 d−1 and in September up to 0.29 d−1) and higher lipid content in microalgal biomass (in June up to 25.6% and in September up to 24.7%). In the experiments conducted in the closed bioreactor, as the ratio I420–520/I580–680 increased, the specific growth rate and the biomass, protein and lipid productivities increased as well. Additionally, the increase in light intensity with red and white LED lamps resulted in faster growth rates (the μexp increased up to 0.36 d−1) and higher lipid content (up to 22.2%), while the protein, fiber, ash and moisture content remained relatively constant. Overall, the trend in biomass, lipid, and protein productivities as a function of light intensity was similar in the two systems (greenhouse and bioreactor).



2013 ◽  
Vol 24 (2) ◽  
pp. 161-166 ◽  
Author(s):  
Jincheng-Yuan ◽  
Jinhui-Song ◽  
Hailian-Ma ◽  
Xiaoqing-Song ◽  
Huiping-Wei ◽  
...  


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