Survival and growth responses of Populus nigra, Salix elaeagnos and Alnus incana cuttings to varying levels of hydric stress

The Salicaceae and Betulaceae are important plant families within riparian ecosystems throughout the Northern hemisphere, and cuttings of species within these families are often used in riparian restoration projects due to their capacity for vegetative (asexual) propagation and rapid growth. Riparian zones can experience a wide range of hydrological conditions and establishing cuttings may be subjected to substantially varying levels of hydric stress from inundation and drought. Tolerance to such stress can vary notably between species, and the absence of knowledge of species-specific responses to inundation and drought has resulted in high mortality in many riparian restoration projects. In this paper, the survival and growth responses of Salix elaeagnos (Salicaceae), Populus nigra (Salicaceae) and Alnus incana (Betulaceae) cuttings in relation to varying rates of water table decline and periods of inundation were investigated using rhizopods during a 69-day greenhouse experiment, in substrates of contrasting sediments (sand versus gravel).

Each species responded differently to the experimental treatments. S. elaeagnos demonstrated an ability to establish in stable, declining and inundated conditions by the production of relatively substantial root and shoot biomass in all treatments, along with elongated roots when experiencing water table decline. P. nigra showed high mortality and poor root and shoot production in inundation treatments, suggesting that this species is intolerant to reduced oxygen conditions. A. incana displayed complete mortality in all gravel-based treatments and high mortality or poor growth in the sand-based inundation treatments. All species showed preferences for stable conditions without inundation, along with slow water table decline for S. elaeagnos. Fast rates of water table decline were detrimental to all species. Overall, sand was a much more effective substrate than gravel for supporting cutting establishment. These results suggest that riparian restoration schemes utilizing S. elaeagnos cuttings may experience greater success than those using the other species investigated. P. nigra cuttings may establish more easily if situated where inundation does not occur often or for prolonged periods, and A. incana cuttings should be planted only where very stable conditions dominate. The study highlights the inter-species variability in the survival and growth response of riparian trees to differing hydrological conditions.     

Effects of light availability and soil flooding on growth and photosynthetic characteristics of Genipa americana L. seedlings

Genipa americana L. (Rubiaceae) is a late successional neotropical fruit tree used in riparian forest restoration programs. We analyze the effects of light availability and soil flooding on the growth and photosynthetic characteristics of G. americana seedlings under nursery and natural light conditions. Two light levels (full sunlight and shade), and two levels of soil water (flooded and control) were used in the experiment. Flooding induced significant changes in the total seedling biomass (P < 0.01). The differences among water treatments were 70 and 10% at full sunlight and shade, respectively. These changes were explained by alterations in the maximum quantum efficiency of the photosystem 2 (Fv/Fm), light-saturated net photosynthetic rates (A _sat) and intrinsic water use efficiency (WUE). G. americana has high physiological plasticity in relation to the light availability and flooding, although significant interactive effects between high light exposure and soil flooding were observed in several photosynthetic and growth variables. The results highlight the importance of the synergistic effects between physical environmental variables on the establishment and growth of G. americana seedlings. In the practical point of view we can indicate that, in degraded riparian forests subjected to soil flooding, seedlings of this species should be planted under partially shaded environments.     

中国紫胶虫生活史及其胶表物候

中国紫胶虫（Ｋｅｒｒｉａｃｈｉｎｅｎｓｉｓ）与其它胶蚧一样，均隐匿在其胶被内生长发育，外观难以看到各虫龄期的体形特征。用图表形式把各虫龄期及其相关的泌胶形态和冬夏两代各自所需无数标出，即可清楚看出该虫生活史、生活周期及各发育阶段期间的变化和关系。同时，列出各虫龄期特征检索表，便于在科研与生产中应用。     

Allelopathic potential of Rhus chinensis on seedling growth of radish,semen cassiae and black soyabean

The allelopathic potential of Rhus chinensis Mill on seedling growth of radish(Raphanus sativus L.),semen cassiae(seed of Cassia obtusifolia L.) and black soyabean [Glycine max(L.) Merr.] was investigated under laboratory conditions.The water extracts of seed,leaf and bark of R.chinensis inhibited the germination and the growth of roots and shoots of radish,semen cassiae,and black soyabean.Significant increasing reductions in the germination and growth of roots and shoots were observed as the concentration of water extract increased in all bioassays.The order of allelopathic potentials of the three parts from R.chinensis plant on seed germination of these receptors was leaf [ seed [ bark.However,the inhibition of water extracts from R.chinensis seed on root activity of semen cassiae was more severe than from the other two parts.The allelopathic potential on the germination of radish was higher than that of black soyabean and semen cassiae.The integrated effect index for allelopathic potential of water extracts of leaf of R.chinensis on radish,semen cassiae and black soyabean seedling growth were-0.88,-0.93 and-0.98 respectively.The results suggested that it is important to minimize the negative allelopathic potential of R.chinensis in agroforestry systems,and to exploit this traditional Chinese medicinal tree for the production of natural bio-pesticides.     

白蜡早春萌芽期树木含水量与枝条颜色变化关系分析

文中分析白蜡早春萌芽期含水量与枝条颜色变化的关系,用以从外观上判断早春萌芽情况。试验结果表明,枝条含水量随萌发进程而变化,在芽萌发前期枝条的含水量急剧下降,之后随芽的萌发含水量增加,枝条颜色随含水量与芽萌发进程呈现出明显的变化。     

杉木、马尾松裸根苗水分关系研究

Water relation parameters of bare-root seedlings of Chinese fir (Cunninghamia lanceolata Hook.)and Masson pine (Pinus massoniana Lamb.)were measured and changes of root growth potential as well as field survival rate of both species were studied after the bare-root seedlings were exposed in a sunny field condition.the results showed that masson pine had a lower osmotic potential(-2.07Mpa) at turgor loss point and at full turgor(-1.29Mpa),compared with Chinese fir(-1.80Mpa and -1.08Mpa respectively).The parameter Vp/Vo(63.27%) of Masson pine was higher than that of chinese fir (58.03%).This means that Masson pine has a stronger ability to tolerate desiccation,compared to Chinese fir according to analysis of above water relation parameters.Root growth potential and field survival rate decreased with prolonging duration of exposure.The field survival rate of both species was reduced to less than 40% after the seedling being exposed only two hours.Water potentials of -1.60 Mpa and -1.70 Mpa were suggested to be critical values for Chinese fir and Masson pine respectively in successful reforestation.     

Impact of mistletoes (Amyema miquelii) on host (Eucalyptus blakelyi and Eucalyptus melliodora) survival and growth in temperate Australia

The damaging effects of mistletoes Amyema spp. on host eucalypts in rural Australia concern many landholders, but few data are available to evaluate mistletoe impacts or formulate management strategies. We used an experimental disinfection approach to determine the effects of a putative pest mistletoe, Amyema miquelii, on its two principal hosts, Blakely's red gum (Eucalyptus blakelyi) and yellow box (Eucalyptus melliodora), on pastoral properties in northern New South Wales. For each host species, pairs of nearby trees were matched for heigth, diameter at breast height, level of mistletoe infestation and distance to neighbouring trees. One tree per pair was chosen at random and all the mistletoes pruned. After 33 months all treated trees were still alive, but among control trees seven of 29 red gums and one of 20 yellow box trees had died. The difference in survival between treated and control trees was significant for red gum. Among surviving pairs of trees, treated trees of both species had significantly greater diameter increments and significantly more foliage than untreated trees. After 33 months, the average increase in relative host foliage biomass attributable to removal of mistletoes was 22% in red gum and 24% in yellow box, compared with untreated controls. The average increase in radial growth attributable to mistletoe removal was 55% in red gum and 49% in yellow box. Diameter increment was negatively and linearly related to mistletoe infestation level in control trees of both species. The differences between infected and disinfected trees in this experiment may underestimate the impact of Amyema miquelii on host growth because small amounts of host biomass were unavoidably lost during disinfection. In a separate experiment, loss of host biomass had a significant negative impact on diameter increment. Although the results indicate that control of serious Amyema miquelii infestation of individual trees will be worthwhile in terms of immediate host survival and higher growth rate, prudent long-term management may well allow for the loss of small numbers of farm trees to mistletoes when planning tree recruitment and utilisation.     

Establishment and growth of container seedlings for reforestation: A function of stocktype and edaphic conditions

A properly selected stocktype can greatly enhance reforestation success through increased survival and growth following outplanting. Implementing a robust stocktype trial using stocktypes of equal quality can ensure results lead to the best choice. Six container types, differing primarily in depth and volume, were used to evaluate the performance of ponderosa pine (Pinus ponderosa Laws. var. ponderosa) seedlings outplanted on two sites that varied in volumetric soil moisture content (θ), average temperature, and total precipitation (mesic and xeric). Seedlings in each container type were cultured specifically to achieve uniform seedling quality. After two growing seasons, seedlings planted at the mesic site showed high survival (>99%) and incremental growth gains of 147, 100, and 794% for height, root-collar diameter (RCD), and stem volume, respectively; container types exhibited differences in total height, RCD, and stem volume with larger containers generally yielding the largest seedlings. Seedlings planted at the xeric site experienced 83% survival, smaller growth gains (25, 46, and 220% for height, RCD, and stem volume, respectively), and also exhibited differences in height, RCD, and stem volume. Regression analysis revealed that for each site, initial seedling morphological characteristics were better at predicting absolute height, RCD and stem volume after the first year than after the second year, with initial seedling height offering the best predictive power (R² = 0.66, mesic site; and R² = 0.70, xeric site). Second-year absolute growth prediction was poorest on the mesic site (R² < 0.21). Regression analysis indicates that initial seedling characteristics lost predictive value with time, especially on the mesic site, as seedlings grew out of their initial, container-induced characteristics and become more limited by current environmental and genetic factors. Conversely, on a xeric site, where absolute growth was reduced, traits determined by the container type persisted longer. Selecting stocktypes for mesic site conditions may only be limited by the minimum growth gains desired. Conversely, xeric sites may benefit from deep-planted quality seedlings or carefully planted long-rooted, large container seedlings.     

角倍蚜干母发生期预测及应用

在 10～ 2 6℃恒温条件下 ,角倍蚜雌蚜的世代生长发育历期符合总积温法则 ,发育起点温度为 3.6℃± 1.1℃ ,有效积温为 358.7日度 ;应用中可根据理论公式和倍蚜的生物温度参数预测雌蚜的世代发育历期 ,并通过调控存放虫袋环境温度的方法控制性蚜的发育速率 ,使干母的发生期应合盐肤木的最适致瘿结倍物候期 ,提高倍蚜虫袋的挂放效果 ;干母的耐饥饿能力弱 ,室温存放只能存活 2 d左右 ,开始发生干母的虫袋应及时挂放     

刚毛柽柳 TheIF1A 基因的互作蛋白及其表达模式分析

翻译起始因子是一类翻译起始所必需的特异蛋白因子,前期研究表明柽柳翻译起始因子 (TheIF1A) 基因能对外界盐和干旱等非生物胁迫做出响应,且过表达 TheIF1A基因能提高酵母和烟草的抗旱耐盐能力。为进一步研究TheIF1A基因的抗逆机制,本研究通过酵母双杂交对柽柳翻译起始因子(TheIF1A) 基因的互作蛋白进行了筛选,共获得5个互作蛋白,分别为RNA聚合酶β II亚基 (RNA polymerase beta II subunit)、ATP合成酶CF1α亚基蛋白 (ATP synthase CF1 alpha subunit protein)、细胞色素b6/f 复合物亚基IV(cytochrome b6/f complex subunit IV)、核酮糖1,5-二磷酸羧化酶/加氧酶小亚基蛋白(ribulose 1,5-bisphosphate carboxylase/oxygenase small subunit)和组蛋白乙酰转移酶(histone acetyltransferase)。利用实时荧光定量PCR对这5个蛋白基因及 TheIF1A 基因在盐和干旱胁迫处理下的表达模式进行分析,结果表明:这些蛋白基因在盐和干旱胁迫下的表达模式与 TheIF1A基因基本一致,表明TheIF1A可能通过与这些蛋白相互作用来参与逆境胁迫应答。为进一步研究TheIF1A 基因的抗逆机理奠定了基础,有利于完善林木抗逆机制的研究,并为通过基因工程手段提高林木抗逆性提供了候选基因。     

角倍蚜人工繁殖技术的效益分析

角倍蚜人工繁殖技术的效益分析王健，傅小川关键词角倍蚜，五倍子，经济效益角倍是主要的五倍子种类之一，质量好、分布面积大，占五倍子总产量的７５％。遵义是五倍子的最佳产区，历史上最高年产曾达到５０００余ｔ．自１９８２年以来，年产仅有５００余ｔ，且处于野生野...     

Low light availability affects leaf gas exchange,growth and survival of Euterpe edulis seedlings transplanted into the understory of an anthropic tropical rainforest

Euterpe edulis Mart. (Arecaceae) is a threatened palm tree of the Brazilian Atlantic Rainforest understory with fundamental importance for the restoration of degraded forest environments. We assessed the leaf gas exchange, growth and survival of E. edulis seedlings transplanted at three different forest sites (S1, S2 and S3) in the same area in which cocoa trees had been cultivated in a rustic agroforestry system. Measurement was carried out during the first year after seedling transplantation. The sites were characterised according to canopy openness (CO) and total daily photosynthetic photon flux density (PPFD). Average CO and PPFD values were 13.3%, 8.0% and 6.7%, and 3.34, 2.79 and 0.62 mol m^?2 d^?1 for S1, S2 and S3, respectively. A progressive decline in seedling survival was observed in all sites throughout the experiment. At 387 d after planting, survival at S1, S2 and S3 was 57%, 44% and 37%, respectively. The gross light-saturated photosynthetic rate (A_max), leaf area and plant biomass were significantly higher (P < 0.05) in S1 and S2 when compared with S3. The values of dark respiration rate (R _d) and photosynthetic compensation irradiance (I _c) were sufficiently low for a positive carbon balance. Notwithstanding, the interpretation of results of microclimate variables together with leaf gas exchange and growth variables indicated that seedlings at all sites were in a suboptimal condition to achieve A_max, which is probably the main cause of the dramatic decline in the seedlings’ survival throughout the first year after transplantation. From a practical point of view, if the values of CO and PFD are lower than 10% and 3 mol m^?2 d^?1, respectively, it is suggested that the transplanting of E. edulis seedlings to the understory of abandoned agroforestry systems be accompanied by cultural practices, such as the thinning and pruning of tree tops.     

Effects of different soil treatments on growth and net nitrogen uptake of newly planted Picea abies (L.) Karst. seedlings

Five soil treatments in a 4-year-old clearcut in southern Sweden affected biomass increase and net nitrogen uptake by planted Norway spruce (Picea abies (L.) Karst.) seedlings through their on net mineralisation and root growth. The patch soil treatments studied were: (i) soil inversion in an old clearcut; (ii) mineral soil from the clearcut remaining, (iii) mineral soil from the clearcut with fertiliser application during the first season; (iv) mineral soil from a nearby uncut forest replacing the clearcut mineral soil; and (v) an untreated control. Growth increased in seedlings in treatments (i) and (iii), but growth in soil treatments with humus removal was not better than that of seedlings in untreated soil. High N uptake early in the first growing season resulted in increased growth during this season in contrast to late N uptake that resulted in a high N concentration in the seedlings after the first growing season. This in turn led to a high growth rate during the next growing season. Generally, both root growth and net N mineralisation were positively correlated to N uptake in the soil treatments. Therefore, a combination of low net N mineralisation and poor root growth as a result of high soil density appears to explain the low N uptake in seedlings in undisturbed soil. The importance of competition with field vegetation for N and water was not clear. Net mineralisation was larger in soil treatments where the humus layer was retained than where it was removed. Net N mineralisation in soil from old clearcuts was the same as in soil from fresh clearcuts.     

Relating the survival and growth of planted longleaf pine seedlings to microsite conditions altered by site preparation treatments

Pine plantations in the southeastern United States are often created using site preparation treatments to alleviate site conditions that may limit survival or growth of planted seedlings. However, little is understood about how site preparations affect longleaf pine (Pinus palustris P. Miller) seedlings planted on wet sites. In a 2-year study (2004 and 2005) on poorly drained, sandy soils of Onslow County, North Carolina, we examined the effects of common site preparation treatments on microsite conditions and quantified relationships between microsite conditions and longleaf pine seedling survival and growth. Treatments used in the study included site preparations designed to control competing vegetation (chopping and herbicide) combined with those that alter soil conditions (mounding and bedding). During both years, mounding and bedding treatments reduced the amount of moisture within the top 6 cm of soil and increased soil temperatures when compared to flat planting (p < 0.001). Soil moisture was inversely related to seedling mortality in 2004 (r² = 0.405) and inversely related to root collar diameter in 2005 (r² = 0.334), while light was positively related to root collar diameter in 2005 (r² = 0.262). Light availability at the seedling level was highest on treatments that effectively reduced surrounding vegetation. Herbicides were more effective than chopping at controlling vegetation in 2004 (p < 0.001) and 2005 (p = 0.036). Controlling competing vegetation, especially shrubs, was critical for increasing early longleaf pine seedling growth.     

《园冶》与《作庭记》的掇石理水

《园冶》和《作庭记》分别是中国和日本最早的造园专著,尽管成书时代、地区不同,但后者体现的深刻汉文化影响,使二者的对比阅读意义重大。通过文本对比,分析二者内在异同,可得《作庭记》体现出早期造园活动中不强调人的进入,而强调微缩自然的庭园特点,以理水为目标、掇石为手段的水石并进的造园思想,及在海洋文化影响下形成的海-岛特征;《园冶》则体现出晚期造园活动中强调人生活其中的园居特点,和山石审美独立完善而水审美退化的地域性造园思想发展。同时,因地制宜的造园理念贯穿了这两部不同背景的造园理论作品,证明场地对东亚造园文化一以贯之的重要性。     

Survival and growth of Acacia dealbata vs. native trees across an invasion front in south-central Chile

Tree invasions cause important conservation problems, such as changes in plant community composition, reduced regeneration rates of native species, and alteration in landscape structures. One of the most invasive tree genera in the world is Acacia (Fabaceae). In Chile, Acacia dealbata Link is distributed in the mediterranean zone, mostly associated with roadsides and anthropogenic disturbances. In this paper we address the following questions: How does A. dealbata perform across a gradient of native forest and invasive stands? Will it be capable of establishing itself in non-invaded native forests and regenerating under its own canopy in the absence of disturbances? From a contrasting viewpoint, will native species such as Cryptocarya alba (Molina) Looser and Nothofagus obliqua (Mirb.) Oerst be able to survive in an A. dealbata stand, allowing re-colonization of the invaded area? We conducted survival and growth experiments on A. dealbata seedlings in three sites near Concepción, Chile (36°S-72°W) under three conditions: under Acacia stand, in a close native forest and on an intermediate matrix between these two conditions. We compared this to the performance of two native trees (Cryptocarya alba and Nothofagus obliqua). Results showed that A. dealbata and C. alba have high growth and establishment capacities within the native forest, but on the intermediate matrix only A. dealbata can grow and survive. C. alba survives at significantly higher rates than A. dealbata within Acacia stand. Nothofagus obliqua only survive at a very low rate in the native forest. Without disturbances, A. dealbata would be successful on the intermediate matrix and within native forest, while C. alba seems capable of surviving and establishing itself in invaded areas, thereby contributing to recovery and restoration of natural spaces. The interplay between Acacia dealbata and the native vegetation may show us a larger picture of how invasive species are capable of expanding even into forested ecosystems and, furthermore, how we can restore native vegetation and avoid further invasion.     

Impacts of burial and insect infection on germination and seedling growth of acorns of Quercus variabilis

Rodents usually exert important role, through their scatter seed hoarding behavior, on plant regeneration in the field. To investigate the effects of burial and insects infection on germination and seedling growth of acorns of Quercus variabilis, perfect and infected acorns were buried in the soil among four depths, 0 cm, 4 cm, 8 cm and 12 cm, to simulate the seed hoarding behavior by rodents in the field. The results showed that (1) the germination rate were both high, under 4 cm burial depth, for perfect and infected acorns (92% and 53% separately), and decreased significantly with increased burial depth; (2) perfect acorns germinated better in 4 cm burial depth group by autumn of first year; (3) there 32% (perfect) and 26% (infected) acorns with 0 cm burial depth, on the soil surface, germinated successfully; for infected acorns, the 4 cm depth group had the best germination or seedling recruitment in both the first year and the second year; (4) acorns of Q. variabilis exhibited dormancy period ca 7 months; (5) burial, infection, and the interaction between these two factors influenced several aspects including stem height, leaf weight, Tannic acid, and biomass within seedling growth; (6) the results from this study suggest that proper burial would be helpful for the germination and seedling growth, and seedlings of shallow buried acorns had an advantage in their early development; and (7) infection by insects will not inevitably influence seedling early development.     

Effects of treeshelters and polyethylene mulch sheets on survival and growth of cork oak (Quercus suber L.) seedlings planted in northwestern Tunisia

Success of plantation establishment depends on the ability of seedlings to withstand animal browsing and competition from vegetation. This study in northwestern Tunisia examined the influence of browsing protection and vegetation control on seedling mortality, diameter, and height growth components of an evergreen sclerophyllous oak species, cork oak (Quercus suber L.) for the first 2 years after planting (2005 and 2006). Browsing protection was controlled by varying both treeshelter type (non-vented, vented, and control) and height (1.2-m and 1.8-m tall). Competing vegetation was controlled through increasing sizes of square-shaped black polyethylene mulch sheets: 0 m, 0.7 m, 1 m and 1.3 m large. Seedling mortality rate was relatively low during the first year (9%) and was not affected by any of the studied factors. During the following year, mortality was lower for seedlings in both types (non-vented and vented) of 1.2-m tall treeshelters than for unsheltered ones. Mortality was only slightly higher for 1.8-m tall shelters than for 1.2-m shelters. Compared to unsheltered seedlings, basal diameter was reduced during both seasons for seedlings inside non-vented treeshelters (1.2-m and 1.8-m tall), whereas for vented shelters it was reduced during the first year and then increased during the second year. Height growth was positively affected by tree shelters during both years. Seedlings inside non-vented 1.8-m tall shelters were the tallest having an average height of up to 140 cm at the end of the second year, while the unsheltered seedlings had only an average height of up to 42 cm. The greater height of the sheltered seedlings was attributed to the increase of: (1) the number of shoot flushes yearly established on the main stem (up to three), and (2) the length of all the growth units produced during each flush. Seedlings inside vented shelters had balanced growth with a low proportion of seedlings unable to support themselves without a stake (7%). However, non-vented shelters had unbalanced height and diameter growths resulting in both a higher height-to-diameter ratio and in a higher proportion of seedlings having stability problems (47%). Polyethylene mulch sheets did not affect early survival, seedling basal diameter, or number of shoot flushes established yearly, but did slightly improve seedling height at the end of the second season, mostly due to the significant improvement in shoot elongation of the first flush. Results suggest that both 1.8 m treeshelters and plastic mulches may enhance the growth of cork oak seedlings planted on harsh sites in northwestern Tunisia.     

Influence of artificial gaps in tropical forest on survival, growth, and Phytolyma lata attack on Milicia excelsa

Milicia excelsa and M. regia are important timber species in moist tropical areas of Africa. They have not been successfully grown largely because of attacks by gall-forming psyllids in the genus Phytolyma. Our objectives were to evaluate the growth of planted Milicia seedlings and incidence of psyllid attack in small (4.2 m²), medium (18.5 m²) and large (>500 m²) artificial gaps in the Bobiri Forest Reserve in the Moist Semi-Deciduous Forest of Ghana. After 13 months, height and diameter growth of Milicia seedlings were significantly greater in the medium and large gaps than in the small gaps. Insect attacks occurred first and most severely in the large gaps, but spread to gaps of all sizes between the 11th and 13th months after planting. While gap size significantly affected the susceptibility of seedlings to psyllid attack, it is not the only factor important in determining susceptibility of Milicia excelsa under field conditions. We conclude that gap sizes in the range of 10–50 m², where irradiances are from 30–60% of full sunlight, in forests similar to those at the study site, seem to be most suitable for regeneration of Milicia.     

The effect of Tuber melanosporum Vitt. mycorrhization on growth, nutrition, and water relations of Quercus petraea Liebl., Quercus faginea Lamk., and Pinus halepensis Mill. seedlings

Mycorrhizal and nonmycorrhizal Quercus faginea Lamk., Quercus petraea Liebl., and Pinus halepensis Mill. one-year-old seedlings inoculated with Tuber melanosporum Vitt. have been analyzed with the purpose of studying the influence of mycorrhization on their growth, water relations, and mineral nutrition. The mycorrhization improved Q. petraea and P. halepensis seedling growth. In addition, the mycorrhization created an elastic adjustment in P. halepensis, although it did not cause any osmotic adjustment. Additionally, the mycorrhization increased phosphorus uptake in Q. faginea and P. halepensis, content of all nutrients in P. halepensis, and N content in Q. petraea.