| 1. |
- Abbasi, Umar Aftab, et al.
(författare)
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Species α-diversity promotes but β-diversity restricts aboveground biomass in tropical forests, depending on stand structure and environmental factors
- 2022
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Ingår i: Journal of Forestry Research. - Göteborg : IVL Svenska Miljöinstitutet AB. - 1007-662X .- 1993-0607.
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Tidskriftsartikel (refereegranskat)abstract
- Forest plays a vital role in the global biogeochemical cycles through a high rate of carbon sequestration and harboring biodiversity. However, local species diversity is declining while also becoming increasingly homogenized across communities. Although effects of local biotic processes (e.g., species α-diversity and stand structural heterogeneity) and environmental factors on aboveground biomass (AGB) have been widely tested, there is a huge knowledge gap for the effect of regional biotic processes (i.e., taxonomic and functional β-diversity) in forests. Here, we hypothesized that regional and local environmental factors along with biotic processes jointly regulate AGB through species shifts in tropical forests.Using piecewise structural equation modeling (pSEM), we linked climatic water availability, soil fertility, stand structural heterogeneity (either tree DBH inequality, height inequality, or stand density), species α-diversity, taxonomic or functional β-diversity (and its two components; β-turnover and β-richness), and AGB across 189 inventory plots in tropical forests of Sri Lanka. Soil fertility and climatic water availability shaped local and regional biotic processes. Stand structural heterogeneity promoted species α-diversity but declined β-diversity (but increased β-taxonomic turnover). Species α-diversity and stand structural heterogeneity promoted AGB whereas taxonomic and functional β-diversity declined (but β-taxonomic turnover increased) AGB.The relationships of AGB with species α-diversity and β-diversity varied from significant to nonsignificant positive depending on the specific combinations of stand structural heterogeneity metrics used. This study shows that local biotic processes could increase AGB due to the local and regional niche complementarity effect whereas the regional biotic processes could restrict AGB due to the regional selection or functional redundancy effect under favorable environmental conditions. We argue that biotic homogenization, as well as drought conditions, may have strong divergent impacts on forest functions and that the impacts of tree diversity loss may greatly reduce carbon sequestration.
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| 2. |
- Bognounou, Fidèle, et al.
(författare)
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Impact of disturbance by roadwork on Pteleopsis suberosa regeneration along roadside environments in Burkina Faso, West Africa
- 2009
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Ingår i: Journal of Forestry Research. - : Springer Science and Business Media LLC. - 1007-662X .- 1993-0607. ; 20, s. 355–361-
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Tidskriftsartikel (refereegranskat)abstract
- The seedling population structure of Pteleopsis suberosa and their regeneration mechanisms were investigated in four roadside environments (graded, adjacent, intermediate and ungraded areas) along paved and unpaved roads in West Africa. A total of 203 quadrats of 2 m × 5 m in size were surveyed and placed along transects parallel to the roads. Within each quadrat, the total number of seedlings and the number of living shoots per seedling base were recorded. Regeneration mechanisms were determined by assessing basal and aerial sprouts and excavating the root systems below ground level. The results show that the total seedling density and the densities of single- and multi-stemmed individuals varied significantly (p < 0.05) among the four roadside environments. However, all seedlings were produced asexually; root suckers were predominant (98%) compared to water sprout (1%) and coppices (less than 1%). This study demonstrates that an intermediate level of soil disturbance from grading along paved and unpaved roads may stimulate P. suberosa regeneration by root suckering. Road type (paved and unpaved) did not affect seedling density, but was a highly significant variable in relation to the coppicing ability of P. suberosa populations in roadside sites. In conclusion, P. suberosa is a disturbance-tolerant species which can proliferate mainly by root suckering after roadwork disturbance.
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| 3. |
- Chen, Xinyu, et al.
(författare)
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Variations in electrical impedance and phase angle among seedlings of Pinus densata and parental species in Pinus tabuliformis habitat environment
- 2015
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Ingår i: Journal of Forestry Research. - : Northeast Forestry University. - 1007-662X .- 1993-0607. ; 26:3, s. 777-783
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Tidskriftsartikel (refereegranskat)abstract
- Electrical impedance (EI) and phase angle (PHI) parameters in AC impedance spectroscopy are important electrical parameters in the study of medical pathology. However, little is known about their application in variation and genetic relationship studies of forest trees. In order to test whether impedance parameters could be used in genetic relationship analysis among conifer species, EI and PHI were measured in a seedling experiment test composed of Pinus tabuliformis, Pinus yunnanensis, and Pinus densata in a habitat of Pinus tabuliformis. The results showed that variations in both EI and PHI among species were significant in different electric frequencies, and the EI and PHI values measured in the two populations of P. densata were between the two parental species, P. yunnanensis and P. tabuliformis. These results show that these two impedance parameters could reflect the genetic relationship among pine species. This was the first time using the two AC impedance spectroscopy parameters to test the genetic relationship analysis between tree species, and would be a hopeful novel reference methodology for future studies in evolution and genetic variation of tree species.
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| 4. |
- Coulibaly-Lingani, Pascaline, et al.
(författare)
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Participatory forest management in Burkina Faso: Members' perception of performance
- 2014
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Ingår i: Journal of Forestry Research. - : Springer Science and Business Media LLC. - 1007-662X .- 1993-0607. ; 25, s. 637-646
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Tidskriftsartikel (refereegranskat)abstract
- This study examines variations in the performance of participatory forest management programs among four forest management groups (FMGs) in southern Burkina Faso, and assesses the factors that influence their members' perceptions of performance through a household survey of 216 members. Variations in performance scores among the FMGs were analyzed through multivariate analysis of variance while multinomial regression analysis was used to identify factors that influence their perception of the performance. The results reveal significant differences in performance scores among FMGs. embers of some FMGs perceived that the participatory forest management program enabled them to get benefits from the sale of fuelwood while performance scores in the forest conservation and decision-making processes is generally poor. The score for economic performance of FMGs in turn was related to better access to roads and markets. Group size tended to enhance economic performance via its strong influence on annual fuelwood harvest, while the resource base appeared to be inconsequential. Members of the forest management groups perceived that large group size and group heterogeneity, particularly in terms of ethnicity, as well as knowledge and awareness of problems related to the forest environment. have no influence on the performance of their respective groups: For rural communities to have a favorable disposition toward sustainable forest management, differences in member understanding of collective actions and their impact before and during the implementation of participatory forest management programs should be considered.
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| 5. |
- Daneshvar, Abolfazl, et al.
(författare)
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Flotation techniques to improve viability of Juniperus polycarpos seed lots
- 2017
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Ingår i: Journal of Forestry Research. - : Springer Science and Business Media LLC. - 1007-662X .- 1993-0607. ; 28, s. 231-239
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Tidskriftsartikel (refereegranskat)abstract
- The germination of freshly collected Juniperus polycarpos (K. Koch) seeds is very low and attributed to the large proportion of nonviable seeds in the seed lots. Thus, the aim of this study was to improve seed lot quality by removing nonviable seeds using two flotation techniques: incubation-drying-separation (IDS) and modified specific gravity (MSG) separation. We examined different IDS conditions (the specific incubation time, subsequent drying time and sorting media) for effectively sorting out nonviable seeds; and tested the feasibility of modified SG separation, which involved soaking seeds in water for a certain period before sorting in different concentrations of sucrose solution. Viable seeds were expected to absorb and metabolically bind more water during soaking than dead seeds could, and hence be sorted effectively depending on the viscosity of the sucrose solution. The viability of the seeds that floated or sank was determined in a topographical tetrazolium chloride (TTC) test. For the IDS trial, 7 days incubation followed by 9 h of drying and sedimentation in pure water or 200 g center dot L-1 sucrose solution identified, respectively, 75 and 82 % of the seeds as viable (sunken) seeds. For the MSG trail, 77 % viable seeds were recovered in the sunken fraction when seeds were soaked for 48 h then immediately sorted in 600 g center dot L-1 sucrose solution. In both cases, the loss of viable seeds in the discarded floating fraction was only 4 %. The results demonstrate that both IDS and MSG separation techniques substantially improved seed lot viability, but MSG separation is simple and needs no modern seed handling facility, and its efficacy relies on seed mass (due to the initial soaking) and the specific density and viscosity of the flotation medium.
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| 6. |
- Daneshvar, Abolfazl, et al.
(författare)
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Growth characteristics and reproductive output of dwarf mistletoe-infected Juniperus polycarpos in Iran
- 2014
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Ingår i: Journal of Forestry Research. - : Springer Science and Business Media LLC. - 1007-662X .- 1993-0607. ; 25, s. 827-834
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Tidskriftsartikel (refereegranskat)abstract
- Dwarf mistletoes are parasitic flowering plants that infect conifers, resulting in substantial loss of growth and mortality. Recently, forest managers in Iran are contemplating whether infection of Juniperus polycarpos C. Koch forests by dwarf mistletoe, Arceuthobium oxycedri (DC.) M. Bieb, influences tree vigor and contributes to insufficient natural regeneration. The present study aimed at assessing the severity of infection and its impact on growth and reproductive output of J. polycarpos. Infected and uninfected trees (n=20 each) were selected for assessment of diameter, height, crown area, and crown volume as well as quantity and quality of cones and seeds. The severity of infection of trees was determined by Hawksworth's 6-class dwarf mistletoe rating (DMR) system. The DMR system revealed that 40% of the infected sample trees were lightly infected (DMR=1-2) and 60% were moderately infected (DMR=3-4). Growth characteristics did not differ significantly (p > 0.05) between infected and uninfected trees. However, moderate infection affected the reproductive output off. polycarpos by significantly (p <0.05) reducing the mean number of cones per unit area of the crown, increasing the number of damaged seeds, and reducing seed size and seed germination capacity. We conclude that reproductive output off. polycarpos is more sensitive than growth characters to moderate infection by juniper dwarf mistletoe, and this might partly account for poor natural regeneration.
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| 7. |
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| 8. |
- Farhadi, Mostafa, et al.
(författare)
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Pre-sowing treatment for breaking dormancy in Acer velutinum Boiss. seed lots
- 2013
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Ingår i: Journal of Forestry Research. - : Springer Science and Business Media LLC. - 1007-662X .- 1993-0607. ; 24, s. 273-278
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Tidskriftsartikel (refereegranskat)abstract
- Acer velutinum Boiss is a valuable tree species native to Iran, and its seeds possess physiological dormancy that hampers seedling production in the nursery for large-scale reforestation efforts. The aim of this study was to determine the optimal dormancy breaking treatments for A. velutinum seeds. We conducted a factorial experiment involving six seed lots collected along an elevation gradient from 300 to 1800 m at 300 m interval and four cold-moist stratification periods (0, 4, 8 and 16 weeks) at 4°C and 70% relative humidity. The result shows that the germination of cold-moist stratified seeds was significantly (p < 0.0001) higher than the control for all seed lots. The highest germination capacity was recorded after 16 weeks of cold-moist stratification for all seed lots (68%-88% depending on the seed lot) except those collected from mid altitude sites (600 and 900 m) that germinated equally well (≥ 75%) after 4- and 8-week of clod-moist stratification compared to the other seed lots. The mean germination time was significantly shorter (12 to 19 days, depending on the seed lot) for seeds stratified for 16 weeks than for untreated seeds. It can be concluded that: (1) cold-moist stratification for 16 weeks is the best pre-sowing treatment for breaking dormancy in A. velutinum seeds; and (2) seeds should be collected from mid altitude sites (600 and 900 m) to get more than 80% germination within 15 days, and these seed lots even required shorter cold-moist stratification period (eight weeks) than other seed lots.
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| 9. |
- Ganea, Laura Stefana, et al.
(författare)
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Development and transferability of two multiplexes nSSR in Scots pine (Pinus sylvestris L.)
- 2015
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Ingår i: Journal of Forestry Research. - : Springer Science and Business Media LLC. - 1007-662X .- 1993-0607. ; 26, s. 361-368
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Tidskriftsartikel (refereegranskat)abstract
- Single sequence repeat (SSR) multiplexing is a semi high-throughput PCR methodology for the analysis of multiple SSRs. We developed two SSR multiplexes selected from SSR loci previously reported in the pine literature and tested the transferability of both SSR multiplexes in nine other pine species. We tested 234 nuclear SSR loci (nSSRs) previously described in the pine literature and selected ten nSSRs following the simple criteria of interpretability and reproducibility. Selected nuclear loci were divided into two nSSRs multiplex sets and their amplification was optimized for three different multiplex PCR methods based on: (a) a custom PCR protocol, (b) a custom protocol with hotstart taq polymerase, and (c) a commercially available kit for SSR multiplexing. To validate their performance, the level of genetic diversity was assessed in three Scots pine natural populations (Hungary, northern Sweden and southern Sweden). In addition, we also tested the transferability of these multiplexes in nine other pine species. We have developed two nSSRs multiplexes of five loci each that will contribute to reduce the costs of nSSR scoring, while increasing the capacity of nSSR loci analysis. Amplification was successful in all three populations (94 % success) and the level of polymorphism (7.1 alleles/marker) was similar to that previously reported for other Scots pine natural populations. Transferability of both multiplexes was successful for those pine species closely related to Scots pine.
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| 10. |
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