6种园林树木对持续性淹水胁迫的生理响应及其比较

以榔榆、榉树、朴树、女贞、枇杷、珊瑚树2年生幼苗为材料,采用盆栽控水试验研究了持续淹水对不同树种外部形态及主要生理指标的影响,探讨了不同树种的抗涝性特性与差异.结果表明:1)淹水胁迫下,不同树种幼苗的生长均受到不同程度的影响,外形表现出明显的水渍斑点和黄化特征,但不同树种受害程度存在一定差异.2)淹水胁迫下,不同树种2种保护酶活性呈现出不同的变化态势.榔榆叶片抗氧化保护酶的活性反应最为敏感,表现为淹水初期SOD活性的显著上升和POD活性的剧烈增加,但后期两种保护酶活性趋于平缓变化;榉树、朴树在整个淹水期SOD活性呈现先期下降后期抬升的波动变化;而女贞、珊瑚树在整个淹水期SOD、POD活性的变化相对较小,不同处理期的测定值差异均不显著.3)榉树、朴树的游离脯氨酸含量变化呈现前期略有下降后期缓慢上升的变化;而女贞、枇杷两树种的游离脯氨酸含量变化呈现先期下降,后期平缓变化的态势.4)淹水初期榔榆MDA含量明显上升,并于淹水第13天时含量最高,榉树和朴树的MDA含量变化呈现先期下降后期缓慢上升的变化,枇杷、女贞的MDA含量变化几乎呈一直线变化.5)6树种叶片中叶绿素含量均随淹水时间的延长而下降.采用隶属函数法对6种树种的耐涝性进行评估,其耐涝性强弱大致排序为:女贞、枇杷、珊瑚树、朴树、榉树、榔榆.     

Effects of soil flooding on leaf gas exchange and growth of two neotropical pioneer tree species

Schinus terebinthifolius Raddi (Anacardiaceae) and Rapanea ferruginea (Ruiz & Pavon) Mez (Myrsinaceae) are two neotropical pioneer trees with wide geographical distribution in South America, highly degree of adaptation to different soil conditions and intense regeneration in areas with anthropic activities. With the aim to recommend the use Schinus and Rapanea in gallery forest restoration programs, we conducted an experiment with the objective to analyze the capacity of these two pioneer trees to tolerate soil flooding, mainly by accessing the effects of flooding on leaf gas exchange, growth and dry matter partitioning. Seedling survival throughout the 56-day flooding period were 100 and 90% for Schinus and Rapanea, respectively. The mean values of stomatal conductance (g_s) and net photosynthesis (A) observed in the control seedlings were, respectively, 0.4 mol m^–2s^–1 and 14 mmolm^–2s^–1, for Schinus, and 0.5 mol m^–2s^–1 and 14 mmolm^–2s^–1, for Rapanea. On day 20 flooding reduced gs and A by 36 and 29% in Schinus, and 81 and 61% in Rapanea. At the end of the experiment, significant decreases were also observed for root and whole plant biomass, in both species. Based on the results, we concluded that seedlings of Schinus and Rapanea can survive and grow throughout a medium period of soil waterlogging, in spite of the alterations observed in their physiological behavior, such as the decreases in stomatal conductance and in whole plant biomass.     

Quantifying flooding effects on hardwood seedling survival and growth for bottomland restoration

Growing interest worldwide in bottomland hardwood restoration necessitates improved ecological understanding of flooding effects on forest tree seedlings using methodology that accurately reflects field conditions. We examined hardwood seedling survival and growth in an outdoor laboratory where the timing, depth, duration, and flow rate of flood water can be carefully controlled while simulating natural soil conditions occurring in floodplains. Flooding treatments were initiated in mid-May and included partial inundation (15–20?cm) during the growing season for 5-week flowing, 5-week standing, 3-week flowing, and control. We monitored the vigor, survival, and growth (changes in basal diameter and stem length) of six hardwood species representing a wide range in expected flood tolerance including eastern cottonwood (Populus deltoides Bartr. Ex Marsh.), pin oak (Quercus palustris Muenchh.), swamp white oak (Q. bicolor Willd.), bur oak (Q. macrocarpa Michx.), black walnut (Juglans nigra L.), and pecan [Carya illinoensis (Wangenh.) K. Koch]. All stock was 1-0 bareroot except that cuttings were used for eastern cottonwood. Five species—eastern cottonwood, bur oak, swamp white oak, pin oak, and pecan—exhibited high survival probabilities (>0.62 for cottonwood; >0.77 for the others) regardless of flood treatment. But of the survivors, only eastern cottonwood and swamp white oak maintained positive growth and healthy green foliage. Despite high survival, bur oak and pin oak suffered stem growth losses and exhibited chlorotic foliage in flood treatments suggesting greater vulnerability to other abiotic or biotic stresses if outplanted on flood-prone sites. Pecan also suffered stem dieback in controls suggesting vulnerability to competition and browsing when outplanted despite high survival after flooding. Our quantitative data helps to confirm and/or refine previously published qualitative flood tolerance ratings for these species, and describes operation of an in situ outdoor flood experiment laboratory that may prove effective in guiding future flood tolerance research.     

不同树种幼林生长差异及对土壤营养的影响

通过调查不同树种新造林树高生长量及其林地土壤有机质和速效氮、磷、钾含量,研究其生长及对土壤营养的影响.结果为：光皮桦、四川桤木、楸树、栾树、湿地松6年生树高分别为8.2、7.7、7.4、7.0、5.3 m;不同树种造林后对土壤营养物质含量的提高有明显差异,5个树种造林后效果排序的先后次序为光皮桦、四川桤木、栾木、楸树、湿地松;新造林均表现为造林当年土壤营养含量明显下降,第2年起逐年增加,第3～5年超过造林前水平.     

Patterns of photosynthesis and starch allocation in seedlings of four bottomland hardwood tree species subjected to flooding

Effects of short-term (32 days) flooding on photosynthesis, stomatal conductance, relative growth rate and tissue starch concentrations of flood-intolerant Quercus alba L. (white oak), bottomland Quercus nigra L. (water oak), bottomland Fraxinus pennsylvanica Marshall. (green ash) and flood-tolerant Nyssa aquatica L. (water tupelo) seedlings were studied under controlled conditions. Net photosynthetic rates of flooded N. aquatica seedlings were reduced by 25% throughout the 32-day flooding period. Net photosynthetic rates of flooded Q. alba seedlings fell rapidly to 25% of those of the control seedlings by Day 4 of the flooding treatment and to 5% by Day 16. In F. pennsylvanica and Q. nigra, net photosynthetic rates were reduced to 50% of control values by Day 8 but remained at approximately 30 and 23%, respectively, of control values by Day 32. Leaves of flooded Q. alba seedlings accumulated approximately twice as much starch as leaves of non-flooded control plants, whereas root starch concentrations decreased to 67% of those of control plants by the end of the 32-day flooding treatment. In contrast, flooding caused only a small increase in leaf starch concentrations of N. aquatica plants, but it increased root starch concentrations to 119% of those of the control plants by the end of the experiment. The co-occurring bottomland species, Fraxinus pennsylvanica and Q. nigra, differed from each other in their patterns of stomatal conductance and root starch concentrations. We conclude that the maintenance of low leaf starch concentrations, and high pre-flood root tissue starch concentrations are important characteristics allowing flood-tolerant species to survive in flooded soils.     

Climatic effects on radial growth of major tree species on Changbai Mountain

? Introduction

Information on spatial variability in tree radial growth is essential for improving predictions of forest ecosystem responses to climate change. To date, researchers have designed models to simulate the potential distribution area of major forest types under different climate change scenarios in Northeast China, but little is known about the spatial variability of tree growth in response to climate.

? Materials and methods

We used a dendroecological technique to examine the climate–growth relationship of six dominant tree species on seven sites varying in altitude on Changbai Mountain in Northeast China, to explore whether the spatial variability of tree growth is an indicator of regional climatic forces, and whether simulation results generated by models can accurately reflect this in tree radial growth.

? Results

Fifteen site-specific species can be distinguished species at or near their upper limit distribution from those at the lower distributions. Species differences were more important than altitude differences in influencing species’ site-specific radial growth. Precipitation, temperature, and soil moisture together constitute the major factors limiting tree radial growth.

? Conclusion

We found the distribution area of dominant tree species on Changbai Mountain will shift upward; growth of Korean pine will not decline at its lower limit of distribution and will not eventually even disappear from forest communities in those areas.     

Lithuanian forests and climate change: possible effects on tree species composition

Outputs from the HadCM3 Global Climate Circulation Model according to scenarios A2 and B1 were used for climate change predictions in Lithuania. According to scenario A2, the annual temperature will increase by approximately 4.0 °C from 2061 to 2090, while scenario B1 predicts an increase of 2.0 °C. In contrast to scenario B1, scenario A2 predicts an annual increase in precipitation of 15–20 % at the end of the century. Based on the predicted climatic data for the two scenarios and climate maps by European Food Safety Authority for the EU, we created climate analogues for Lithuania for 2031–2060 and 2061–2090. These areas were overlain by the digital map of native tree species distributions in Europe, which was created from the European Forest Genetic Resources Programme database. If climate changes occur according to scenario B1, in 2031–2060, Lithuania’s climate will become suitable for approximately five to six alien species, such as Acer campestre, Acer pseudoplatanus, Fagus sylvatica, Populus nigra, and Prunus avium. In 2061–2090, these species will be joined by Sorbus domestica and Tilia platyphyllos. If climate changes occur according to scenario A2, at the end of the twenty-first century, Castanea sativa, Quercus pubescens, and Sorbus torminalis could expand this list. With respect to species dispersal rates, there is a high probability that the species A. campestre, A. pseudoplatanus, P. nigra, and P. avium will become immigrants to Lithuanian forests at the end of the twenty-first century. Approximately 20 new species native to Europe will be suitable for cultivation (scenario A2). Climate change will affect the distributions of native species too. An increase in the proportion of deciduous tree species (except Alnus incana) and some reduction in the proportion of conifers, Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), are expected in Lithuanian forests.     

Effect of flooding on C metabolism of flood-tolerant (Quercus robur) and non-tolerant (Fagus sylvatica) tree species

Flooding is assumed to cause an energy crisis in plants because-due to a lack of O(2)-mitochondrial respiration is replaced by alcoholic fermentation which yields considerably less energy equivalents. In the present study, the effect of flooding on the carbon metabolism of flooding-tolerant pedunculate oak (Quercus robur L.) and flooding-sensitive European beech (Fagus sylvatica L.) seedlings was characterized. Whereas soluble carbohydrate concentrations dropped in roots of F. sylvatica, they were constant in Q. robur during flooding. At the same time, root alcohol dehydrogenase activities were decreased in beech but not in oak, suggesting substrate limitation of alcoholic fermentation in beech roots. Surprisingly, leaf and phloem sap sugar concentrations increased in both species but to a much higher degree in beech. This finding suggests that the phloem unloading process in flooding-sensitive beech was strongly impaired. It is assumed that root-derived ethanol is transported to the leaves via the transpiration stream. This mechanism is considered an adaptation to flooding because it helps avoid the accumulation of toxic ethanol in the roots and supports the whole plant's carbon metabolism by channelling ethanol into the oxidative metabolism of the leaves. A labelling experiment demonstrated that in the leaves of flooded trees, ethanol metabolism does not differ between flooded beech and oak, indicating that processes in the roots are crucial for the trees' flooding tolerance.     

不同树种生长适应性及其对土壤微生物数量的影响

通过调查不同树种新造林树高生长量、保存率及其土壤细菌、真菌、放线菌数量等,研究其生长、适应性及对土壤微生物数量的影响。结果表明：光皮桦、桤木、楸树、栾树、湿地松5年生树高分别为7．4、6．5、6．3、4．8、4．2m,保存率分别为92％、65％、82％、78％、90％;不同树种造林后对土壤微生物数量的提高有明显差异,5个树种造林后林分土壤微生物数量提高的效果排序为桤木〉光皮桦〉栾木〉楸树〉湿地松;新造林均表现为造林当年土壤微生物数量明显下降,一般下降35％～40％,第2年底回升并超过造林前水平,第3-5年逐年增加。     

兰州市主要绿化树种滞尘效应

对兰州市6种常见的绿化树种的滞尘能力进行了测定分析,结果表明,不同树种的滞尘能力存在很大的差异,排序为:红叶李 > 毛白杨 > 大叶黄杨 > 臭椿 > 国槐 > 垂柳,可为兰州市的大气污染生态治理提供依据。       

Selective logging alters allometric relationships of five tropical tree species in seasonal semi-deciduous forests

In selectively logged forests,trees are more likely to expand their diameters(D)at the expense of height(H)growth,resulting in variations in H:D relationships.This study examines how selective logging affects the H:D allometric relationships of five common tree species and whether the effects vary with functional groups(shade-intolerant or shade tolerant)in seasonal semi-deciduous forests.Individuals of five species in a 3000 m^2(0.3 ha)plot were marked and heights and diameters recorded.Most of the species,with one exception,showed greater investment in diameter per increment of height compared to an unlogged forest,possibly because of the greater light available.This study shows the effects of selective logging on species populations as evidenced by increases in H:D ratios.Comparison of forest fragments with different degrees of human impact is important because it allows us to understand the differences in architectural characteristics caused by selective logging.     

Effects of flooding on the recruitment, damage and mortality of riparian tree species: A field and simulation study on the Rhine floodplain

The extensive flooding by the river Rhine on May 12 1999 provided an opportunity to investigate the impact of such an extreme event in terms of damage and mortality of adult trees in floodplains. Such data is highly valuable for determining the potential impact of climate change on the zonation of tree species along rivers. We analysed an extensive dataset of the damage and mortality suffered by groups of adult trees of the following species as a consequence of this flood: the hardwoods Acer campestre L., Acer platanoides L., Acer pseudoplatanus L., Alnus glutinosa (L.) Gaertn., Carpinus betulus L., Fagus sylvatica L., Fraxinus excelsior L., Juglans nigra L., Prunus avium (L.) L., Quercus robur L., Tilia cordata Mill., Ulmus laevis Pall. and Ulmus minor Miller, and the softwoods Salix spp. L. and Populus spp. L.A logistic survivorship curve revealed that mortality of A. platanoides, A. pseudoplatanus and T. cordata increased significantly with increasing duration of flooding; C. betulus and F. excelsior showed a significant increase of damage and mortality with increasing flooding depth. There was no mortality of Salix spp. and Populus spp. in either the flooded or unflooded areas. No statistically significant relationships were found for the other tree species. Multivariate analysis revealed that flooding duration, flooding depth and flooding velocity explain 19%, 11% and 8%, respectively, of the variation in damage and mortality of trees.The survivorship curves of adult trees obtained in this study were combined with similar curves of saplings based on an earlier study and applied in an individual-tree, process-based simulation model. The simulated effects of flooding on an initial random distribution of trees species on a hypothetical floodplain resulted in a realistic zonation of tree species along the river. When extreme events were simulated, the zonation shifted upward. This demonstrates the model's usefulness in assessment and planning studies of the impacts of climate change on tree species composition in river floodplains in north-west Europe.     

The effects of belowground resources on aboveground allometric growth in Bornean tree species

Tree height and crown allometries reflect adaptations for resource acquisition and structural stability, as well as plastic responses to a heterogeneous environment. While both light and soil resources limit growth and influence competitive responses in tropical forests, the effects of belowground resources on allometries are less understood, especially within the understory. To characterize outcomes of tree competition along an edaphic resource gradient, we quantified variation in height and crown allometries of six Bornean tree species from contrasting regeneration niches (light-demanding vs. shade-tolerant) on two soil habitats (clay-fine loam and sandy loam) within a 52-ha forest dynamics plot. Using empirically-fit allometric parameters and diameter growth rates from plot census data, we modeled tree height and crown area growth over the projected life span of each species. Based on resource competition theory, we hypothesized that tree species specializing on and populations of generalist species growing on the relatively moister, more fertile clay-fine loam soil habitat would have faster height and crown growth rates, compared to those on the sandy loam habitat, regardless of regeneration niche. Among soil specialists and within generalists of both genera, trees growing on clay-fine loam had taller stems and larger crowns at a given age and faster height and crown area growth rates at most sizes than trees on sandy loam. Differences in height and crown growth were driven by the faster diameter growth rates of trees on clay-fine loam, not by differences in height- and crown-diameter allometries, as trees on sandy loam were significantly taller at a given diameter, and differences in crown allometry were not consistent across soil habitats. Characterizing the height and crown growth responses of trees along resource gradients provides insight into the mechanisms that maintain diversity in tropical forests. Our results point to the importance of adaptive and plastic responses to both above and belowground resource availability in determining the allometric growth of trees and suggest that this diversity of responses may contribute tree species coexistence through competition-based trade-off mechanisms and variation in growth among individuals. Additionally, as the importance estimating natural carbon sequestration increases with the escalating effects of anthropogenic climate change, differences in tree growth and architecture across soil habitats also have implications for the approximation of forest carbon storage on heterogeneous tropical soils.     

Light- and nutrient-related relationships in mixed plantations of Eucalyptus and a high diversity of native tree species

New Forests - Mixed plantations composed of Eucalyptus intercropped with a high diversity of native tree species are a promising option for combining biodiversity recovery with wood production...     

Foliar pathogen and insect herbivore effects on two landslide tree species in Puerto Rico

To better understand pathogen/herbivore interactions and landslide regeneration, percent leaf area lost to disease and herbivory on two Puerto Rican trees over a 1-year period was sampled. Cecropia schreberiana saplings lost from 1 to 3% leaf area to pathogens and from 1 to 7% to herbivores. For Inga vera, both sapling and seedling losses to pathogens were minimal, but Inga herbivory losses reached 25% for saplings and 34% for seedlings. The most common fungi on Cecropia leaves were species in the genera Phoma and Phyllosticta, and on Inga leaves was Colletotrichum gloeosporioides. Percent survivorship after 1 year in the field varied among species and life-form (46% for Cecropia saplings, 15% for Inga saplings, 0% for Inga seedlings). There were no effects of pathogens or herbivores on survivorship or growth, but increased levels of herbivory did significantly correlate with total phenolics and condensed tannins in both Inga seedlings and saplings. For both seedlings and saplings of two trees on the neotropic island of Puerto Rico: (1) leaf herbivory was modest and leaf losses to pathogen disease were small; (2) these mechanisms did not affect survivorship or growth; (3) a neotropical tree (I. vera) displayed increased levels of secondary chemicals in its leaves, correlated with increased levels of insect herbivory.     

Allometric relationships of frequently used shade tree species in cacao agroforestry systems in Sulawesi, Indonesia

Shade trees play an important role within agroforestry systems by influencing radiation and wind regimes as well as nutrient and hydrological cycling. However, there is a lack of quantitative assessments of their functions. One of the reasons is the rare information on structural characteristics of shade tree species. Therefore, the aim of this study is to provide basic information on the structure of frequently used shade tree species for the implementation of models simulating the ecosystem processes in agroforestry systems. The investigation of the shade trees was conducted at two cacao agroforestry sites on Sulawesi, Indonesia. The measurements of the main structural parameters: diameter at breast height, tree height, trunk height, crown length and crown radius were carried out for the shade tree species Aleurites moluccana, Cocos nucifera and Gliricidia sepium. For data collection, the National Forest Inventory Field Manual Template by FAO (2004) was applied. Based on this information allometric functions were derived for the correspondent shade tree species. The best significant relationships were obtained for the height-crown length relationship of the dicotyledonous tree species’ A. moluccana and G. sepium with a coefficient of determination r² = 0.925 and r² = 0.738, respectively, and the height-crown length relationship of the monocotyledonous palm C. nucifera with r² = 0.663. The transferability tests ‘analysis of covariance’ and ‘homogeneity of slopes’ have shown that the obtained allometric functions are also applicable to other cacao agroforestry systems of the region.     

Effects of complete submergence on seedling growth and survival of five riparian tree species in the warm-temperate regions of Japan

To reveal the relationship between tolerance to submergence and the distribution ranges of riparian tree species in the floodplains of the warm-temperate regions in Japan, we assessed the response and tolerance of current-year seedlings of two Salix and three Ulmaceae species to submergence treatments for 1, 2, 4, and 8 weeks. We investigated shoot elongation, number of leaves, and survival rate of seedlings during the experiment, and biomass allocation was determined at the end of the experiment. Shoot elongation and leaf production of seedlings were suppressed in all the species during the submergence treatments. However, the seedlings of Salix chaenomeloides and S. pierotii elongated shoots rapidly and produced leaves after the treatments. All the underground biomass in these two species was larger than aboveground biomass. These results are considered as typical responses of flood-tolerant species. In contrast, the underground biomass of Ulmaceae seedlings (Celtis sinensis var. japonica, Aphananthe aspera, and Ulmus parvifolia) decreased more rapidly than aboveground biomass during prolonged submergence. Furthermore, A. aspera seedlings also showed suppression of shoot elongation and leaf production after the treatments. Our results indicate that the three Ulmaceae species are less tolerant to submergence than the two Salix species. In conclusion, we suggest that submergence stress is one of the important factors determining the distribution of tree species in the floodplains of lowlands in the warm-temperate regions of Japan.     

Significant differences and curvilinearity in the self-thinning relationships of 11 temperate tree species assessed from forest inventory data

Introduction  

In pure and even-aged stands, the allometry between mean tree size and maximum stand density—or self-thinning relationship—has long been considered a constant among tree species. Although the self-thinning allometric coefficient has been shown to be species-dependent, estimates available for a given species also differ. Whether this coefficient truly varies across species thus remains an open issue. A potential cause of variation in the coefficient may lie in a departure from the allometric assumption in the self-thinning relationship.     

Planning tree species diversification in Kenya based on differences in tree species composition between farms. I. Analysis of tree uses

Concerns exist about the limited diversity of tree species in agricultural landscapes. Complete tree inventories were carried out on 201 farms from four villages in western Kenya to establish whether significant differences in tree species composition existed between farms, and if so their magnitude and implications for new introductions and plantings. Tree species composition was interpreted to encompass elements of both tree identity and abundance. Tree identity was viewed from both taxonomic and function (e.g. fruit, timber, medicine) perspectives. Novel types of ordination using the Hellinger ecological distance and polynomial Redundancy Analysis indicated wide heterogeneity between farms with respect to tree species composition. For the 12 most prevalent functions of trees, the analyses showed significant differences (p<0.05). Partitioning of variance identified that village location explained much of the differences between farms suggesting that farmers share tree species within villages more than between villages. Differences between farms were assessed on two-dimensional ordination graphs. For five important tree functions, including beverage, charcoal, construction, fodder and medicine, two species dominated the compositional differences. For these functions, diversification can be achieved by village-to-village sharing even in the absence of any new species introductions. A general process to determine the degree of tree diversity at farm and landscape levels and steps to increase it are discussed.