查看更多>>摘要：Abstract Key message Epiphytic lichens of remnant Atlantic oakwood trees, enclosed within a recently planted conifer matrix, show ability to survive early stages of?woodland restoration (conifer removal).Context Atlantic oakwood, ancient semi-natural woodland (ASNW), supports important epiphytic lichens. Fragmented ASNW, historically in-filled with conifers, are now being restored to reflect ASNW tree and ground flora character. Concerns exist that sudden and total removal of the conifer matrix will be detrimental to the epiphyte diversity of remnant trees retained within the former plantation.Aims Here, we ask whether an unintended consequence of habitat restoration is the loss of epiphyte populations on remnant trees.Methods Dynamics of ground flora development were studied at one 50-ha site on the west coast of Scotland using indicator species occurrence and species traits. Change in cover of lichen species was determined and lichen vitality was assessed in two Lobaria species using chlorophyll fluorescence as a proxy. Assessments pre-, post- and nine years after conifer removal were made in plantation areas (containing remnant oak trees) and ASNW areas.Results Re-vegetation of the ground flora was predominantly by ASNW vegetation. Species richness and occurrence of native woodland indicator species increased and the community showed stronger competitor traits. Lichen vitality was initially reduced but recovered. Tests showed change in the abundance of key lichen species and lichen community diversity was non-significant despite the loss of four lichen species on remnant trees.Conclusion Ground flora dynamics indicate site recovery was underway within eight years of restoration activities and epiphytic lichens although variable in response were in this study largely unaffected, this restoration approach could be appropriate for other Atlantic oakwoods where lichen conservation is an objective.
Li YuejuanZhang YuanyeLiao Pei-ChunWang Tianrui...
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查看更多>>摘要：Abstract Key message Leaf symmetry and leaf size are explained by genetic variation between and within lineages and to a lesser extent by climatic factors, while leaf asymmetry can only be partly explained by geographic factors in Quercus aquifolioides Rehder & E.H. Wilson.Context Leaves are the primary photosynthetic organs of plants, and their morphology affects various crucial physiological processes potentially linked to fitness.Aims We explored the variation in leaf morphology of an alpine oak, Quercus aquifolioides, in order to examine its relationship to genetic, geographic, and climatic factors.Methods We conducted a genetic survey using 25 nuclear microsatellites. Based on Bayesian clustering analysis, 273 sampled trees from 29 populations of Q. aquifolioides were assigned to two lineages that correspond to the Western Sichuan Plateau-Hengduan Mountains (WSP-HDM) and Tibet geographic areas, with some individuals showing mixed ancestry. To undertake morphological analyses, we collected 1435 leaves from these trees and characterized them in terms of 13 landmarks. The metric dimensions of these leaves were digitally captured in the two-dimensional coordinates of these landmarks, then divided into leaf size and symmetric and asymmetric components of leaf shape. To analyze how different components of leaf morphology vary across lineages, we employed Procrustes Analysis of Variance (ANOVA), two-block partial least-square analysis (2B-PLS), and several other multivariate analysis approaches. We also applied distance-based redundancy analysis (dbRDAs) to explore relations between leaf morphology and genetic, geographic, and climatic factors.Results Multivariate analysis indicated significant differentiation in leaf symmetric shape components and leaf size between the WSP-HDM and Tibet lineages, while the mixed individuals were morphologically intermediate. The dbRDA analysis showed that most of the variation in symmetric components and leaf size was explained by genotypic effects, with the symmetric components of leaf shape being also significantly explained by geography and climate; however, variation in asymmetric components is only very weakly explained by geography.Conclusion Our results demonstrated that leaf morphological variation in shape and size across Q. aquifolioides geographic range is related to both its genetic differentiation and to a lesser extent to climatic factors. We discuss how these patterns could be interpreted in terms of both geographical isolations among and within lineages, and possible adaptive responses for particular traits, in contrast to asymmetric variation.
查看更多>>摘要：Abstract Key message We tested how nutrient supply and interspecific belowground competition affect ecophysiological and morphological responses to elevated CO2 in black (Picea mariana (Mill). B.S.P) and white spruce (Picea glauca [Moench] Voss.). It is found that belowground competition and high nutrient greatly enhanced the relative performance of black spruce over white spruce at elevated CO2.Context We have previously found that interspecific belowground competition reduce growth, whole seedling photosynthesis, and biomass allocation to leaf and that belowground competition and nutrient supply affect responses to elevated CO2 in the above two species, but we did not examine the physiological and morphological mechanisms of the responses.Aims To examine the interactive effects of belowground competition, nutrient supply and elevated CO2 on root morphology, photosynthetic rate, and biochemical and photochemical capacity of photosynthesis in black spruce (Sb, Picea mariana [Mill.] B.S.P.) and white spruce (Sw, Picea glauca [Moench] Voss.).Methods Seedlings were grown in individual containers (no belowground competition) or in a common container (belowground competition) under 380 vs. 720?μmol?mol?1 CO2 and high vs. low nutrient supply in the greenhouse for one growing season.Results Elevated CO2 stimulated photosynthesis and nutrient use efficiency to a much greater degree in black than white spruce when they were grown in the same container, particularly under high nutrient supply. The ability to produce a greater length of roots per unit volume of soil was associated with the response of black spruce.Conclusion The synergistic effects of elevated CO2 and belowground competition on the physiology and root morphology of black spruce suggest that elevated CO2 will likely increase the relative competitiveness of black spruce over white spruce.
查看更多>>摘要：Abstract Key message Whole-tree harvesting makes forests more profitable than conventional harvest as long as the impact on tree growth remains under 2.3% for even-aged oak (Quercus petraea(Matt.) Liebl.) and 3.4% for sweet chestnut (Castanea sativaMill.) coppice with oak standards. Coppice-with-standards may have potential to be more profitable than even-aged oak in case of 50% rise in fuelwood prices with 10% decrease in timber prices.Context Making the shift to renewable energy sources requires increasing biomass removal from the forest in a sustainable way. Today, the most common practice for forest biomass extraction is whole-tree harvesting rather than conventional harvest in which only stems are harvested or sometimes branches larger than 7 cm in diameter. However, intensive biomass harvesting can certainly increase economic profitability but it could affect long-term forest productivity because more nutrients are exported from sites.Aims We explored the land expectation value of even-aged oak (Quercus petraea (Matt.) Liebl.) and sweet chestnut (Castanea sativa Mill.) coppice with oak standards under different discount rates and wood prices scenarios, tree mortality triggered by climate variation as well as the effects of a decrease in forest productivity due to whole-tree harvesting on the land expectation value (LEV).Methods We modeled two plausible harvesting scenarios for both stands and assessed their LEV. We first analyzed the sensitivity of the valuation results to discount rate, wood prices changes, and increased tree mortality rates. Second, we compared conventional harvest to whole-tree harvesting in which removing the fine wood implies a decrease in tree growth over the long term (between 1 and 10%).Results In the current economic situation, the LEV of even-aged oak is higher than coppice-with-standards but this situation could be reversed in case of rising energy prices and lower timber prices in the future. The variation of the discount rate has a significant impact on the LEV but 3% seems to be adequate for European forests. A gradual increase in annual tree mortality rate of 0.6 and 0.9% along even-aged and CWS rotation, respectively, reduced the LEV by half, while increased mortality with constant rates along the rotations had more negative effect on the LEV than gradual increases: 0.4–0.5% increases in mortality rates reduced both LEV’s by half.Whole-tree harvesting is able to improve the LEV for both stands by 36 to 64% compared to conventional harvest; but this improvement of LEV only lasts as long as the impact on tree growth remains under 2.3 and 3.4%, respectively, for even-aged oak stand and coppice-with-standards.Conclusion Whole-tree harvesting system increases forest profitability as long as the sustainability guidelines for biomass harvesting are respected. With the increased demand for fuelwood, the coppice-with-standards regime may become financially attractive once again and fulfill a multitude of forest owner objectives with a wide range of additional options.
查看更多>>摘要：Abstract ? Key message Understanding forest genetic diversity and national legislation on trade and utilization of forest reproductive material (FRM) are key aspects for management and adapting forests to climate change. Despite concerns about the negative effects of climate change on forests, awareness of the role of genetic diversity in climate change adaptation is limited.? Context Adaptive forest management strategies such as afforestation and reforestation depend on the selection of appropriate FRM and their knowledge among the relevant stakeholders.? Aims To analyze the perceptions among the forest, conservation, and nursery managers of six Central European countries on awareness of genetic diversity and practical and legislative issues of afforestation and reforestation in climate change.? Methods A survey was conducted with structured questionnaires.? Results Around 80% of the respondents believe in climate change. Local FRM is preferred for reforestation. Although 80% of the conservation and forest managers perceive the importance of forest genetic diversity, almost half of them feel unaware of it. The majority of respondents believe that national and European legislation on seed transfer is not adapted to climate change.? Conclusion Inadequacy in the awareness of genetic diversity and policies on FRM is likely to influence forest adaptation to climate change in Europe.
Stefanowska SaraMeyza KatarzynaIszku?o GrzegorzChybicki Igor J....
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查看更多>>摘要：Abstract Key message Taxus baccata remnants established recently tend to contribute less to the species’ overall genetic variation than historical populations because they are subjected to a greater impact of the founder effect and genetic isolation. As tree trunk perimeter is a rough indicator of genetic variation in a population, this measure should be considered in conservation programs.Context Genetic variation within Taxus baccata (L.) populations is not associated with the current census size but correlates well with the effective size, suggesting that genetic drift intensity reflects variation in demographic histories.Aims We hypothesize that recently established populations are subjected to greater bottleneck than old remnants. Using the mean trunk perimeter as a surrogate of tree age, we test whether the demographic history and genetic variation are associated with the mean tree age.Methods Using 18 microsatellite markers, we analyze the genetic diversity and demographic history of 11 yew populations in Poland to assess the relationship between the mean trunk perimeter and the inferred genetic parameters.Results Populations reveal significant differences in levels of genetic variation and in the intensity and time of genetic bottleneck. After excluding an apparent outlier, the genetic variation is significantly greater while the bottleneck intensity lower in populations with a greater perimeter.Conclusion Due to continuous species decline and increasing fragmentation, the non-uniform contribution of yew remnants to the overall genetic variation tends to decrease together with the mean tree age. Germplasm collections for the species should take into account tree perimeter as a rough indicator of the genetic variation of a population.
NSTL
Springer Nature