Biomass production of trees and grasses in a silvopasture system on marginal lands of Doon Valley of north-west India 2. Performance of grass species

In a long-term study (1980 to 1993), the survival, growth performance and biomass production of two grass species viz. Chrysopogon fulvus (Spreng.) Chiov. and Eulaliopsis binata (Retz.) C.E. Hubb. were assessed when intercropped with four tree species viz. Albizia lebbek (L.) Benth., Grewia optiva Drumm., Bauhinia purpurea L. and Leucaena leucocephala (Lamk.) de Wit. on the bouldery riverbed lands of Doon Valley of north-west India. The survival of grass clumps was higher under the canopy of B. purpurea (48.3% in 1993 of the initial planting density of 20,000 clumps ha⁻¹ in 1980) and G. optiva (47.4%) than of L. leucocephala (31.1%) and A. lebbek (29.4%), and at 75% intensity of tree lopping (40.9%) than at 50% (37.1%). The effect of tree species on different growth parameters of grasses was not uniform, with G. optiva and B. purpurea causing comparatively more synergistic effect on clump height and clump diameter respectively. Although the performance of grasses was good under A. lebbek and L. leucocephala in the early years (1980--1987), these tree species resulted in the lowest grass dry weight in the later years up to 1993. The beneficial effect of higher lopping intensity of 75% was observed on the growth and biomass production of grasses over 50% lopping, presumably due to increased light penetration into the under-storey. The biomass production of grasses reached a maximum at four years of growth in 1983, after which, it decreased gradually to less than half in 1993. Eulaliopsis binata showed higher survival, growth and biomass production than C. fulvus throughout the period of study. The total biomass production was highest in association with B. purpurea followed by G. optiva, which appeared to be the most suitable tree species along with E. binata for sustainable silvopasture development on the marginal lands of Doon Valley of north-west India. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of lopping on water potential, transpiration, regrowth, (14)C-photosynthate distribution and biomass production in Alnus glutinosa

The effects of light, moderate and heavy branch pruning or lopping treatments (resulting in removal of 28-31, 56-60 and 80-82% of the foliage, respectively, unlopped control = 0%) were studied in 3-year-old black alder (Alnus glutinosa L. Gaertn.) plants. Within 24 h of lopping, transpiration rates decreased and water potentials increased. The effects of lopping continued for 48 days. The improved water status of the lopped plants enhanced water-use efficiency during the first 30 days. Regrowth was related to a combination of enhanced net assimilation rates during the first 30 days after lopping, use of current photoassimilates and stored carbohydrates in the roots (particularly in medium and heavily lopped plants) for the production of new leaf area, and delayed leaf senescence. The lightly and moderately lopped plants developed 62 and 57% more leaf area, respectively, than the unlopped plants, but total leaf area development was slower in the heavily lopped plants. Lightly lopped plants produced total biomass equivalent to that of unlopped plants, but the moderately and heavily lopped plants produced less biomass than the unlopped plants. During the first 30 days after lopping, there was a net loss of nodule dry matter and recovery to control values did not occur during the period of study. Immediately (24 h) after lopping, more (14)C-photosynthate was translocated to the roots of lopped plants than to the roots of unlopped plants. When a branch near the base of the main stem was fed (14)CO(2), (14)C-photosynthate translocation to the shoot increased with increasing intensity of lopping, at 50 days after lopping.     

Studies on root distribution of five multipurpose tree species in Doon Valley,India

Observations on the growth performance, rooting behaviour and distribution of fine roots of five tree species viz., Bauhinia purpurea, Grewia optiva, Eucalyptus tereticornis, Leucaena leucocephala and Ougeinia oojeinensis (Family: Papilionaceae) are being presented here. Roots were exposed at the time of planting, 6 months, 16 months, and 28 months after planting. Total root weight and root volume were highest in Eucalyptus tereticornis and lowest in Bauhinia purpurea. Major part of the root system confined within 90–120 cm soil depth in case of Bauhinia purpurea, Grewia optiva and Leucaena leucocephala but Eucalyptus tereticornis and Ougeinia oojeinensis strike their roots to deeper depths. Bauhinia purpurea had its roots evenly distributed down to 120 cm. In general, the vertical distribution of fine roots (< 2 mm in diameter) of the five species indicate that more the depth, fewer the number of roots. The observations on soil binding capacity, indicated that Ougeinia oojeinensis had the maximum and Eucalyptus tereticornis had the minimum binding value. Due to leaf shading and other litter fall significant increase of nutrient components in soils under the tree canopies has been observed. The study indicates that bulk of the roots of the five tree species are found near the surface, but observation on soil moisture and nutrient content does not indicate variation under the tree canopies and in open, hence there may not be root competition in initial years of plantation.Authorised for publication by the Institute as contribution No.3311/239/89.     

羊蹄甲属5个树种花粉生活力测定

采用 MTT 法和离体萌发法对红花羊蹄甲（Bauhinia blakeana）等5个羊蹄甲属树种花粉生活力进行测定,结果表明,红花羊蹄甲、黄花羊蹄甲（B. tomentosa）、宫粉羊蹄甲（B. variegata）、橙红羊蹄甲（B. galpinii）和羊蹄甲（B. purpurea）花粉 MTT 染色率分别为40.3%、79.8%、93.6%、95.7%、100%,羊蹄甲、宫粉羊蹄甲、橙红羊蹄甲花粉细胞生活力较其他两个树种要高;离体萌发试验测得以上5个树种的花粉萌发率差异很大,红花羊蹄甲、黄花羊蹄甲、宫粉羊蹄甲、橙红羊蹄甲和羊蹄甲花粉的最高萌发率分别为0、23.0%、92.1%、50.0%、80.3%,其中宫粉羊蹄甲花粉萌发率最高,羊蹄甲花粉次之,红花羊蹄甲花粉不萌发。以上5个树种中宫粉羊蹄甲及羊蹄甲的盛花期花粉可以作为人工授粉进行杂交育种较为理想的花粉来源。宫粉羊蹄甲花粉最适离体萌发培养基配方为蔗糖220 g/L+硼酸20 mg/L。     

低温胁迫下羊蹄甲和洋紫荆家系叶片相对电导率的变化

羊蹄甲Bauhinia purpurea和洋紫荆Bauhinia variegata是羊蹄甲属常见的景观树种,为研究其不同家系的抗寒能力,利用电导法分别对半年生实生苗进行人工低温胁迫试验。结果表明:随着低温胁迫的加重,各家系的叶片相对电导率整体呈上升趋势,且不同家系叶片的相对电导率增长速率不同,表明低温胁迫下各家系叶片的质膜受损程度不同。结合其形态特征变化和后期恢复速度,发现羊蹄甲Y15、洋紫荆G48、G26、G34家系的叶片相对电导率上升幅度较小,低温胁迫后恢复生长情况良好,表明其抗寒性较强。     

Analysis for dry and wet years with the WIMISA model of tree-crop competition for windbreak systems in the Sahel

A modelling approach was chosen for analyzing the effects of competition between windbreaks and crops for soil water and radiation in the Sahel. The model has a high spatial and temporal resolution to account for the heterogeneity in a windbreak-cropping system. The model was parameterised for millet (Pennisetum glaucum (L.) R. Br.), the tree species Bauhinia rufescens Lam. and soil characteristics and weather data of Sadoré, Niger. Simulations were run for two wet years (1992 and 1993) and for a dry cropping season (1989). Simulations showed a strong yield reduction up to 2 m from the windbreak due to shading and/or water competition. For Sahelian sites with no access to groundwater, competition for water between trees and crops is likely to occur in the beginning of the rainy season. Water competition was surprisingly highest in the wet year 1992, intermediate in the dry year 1987 and lowest in the wet year 1993. Simulation results indicate that light and water competition depends on rainfall distribution and the period between the seasonal onset of tree and crop growth. This revised version was published online in June 2006 with corrections to the Cover Date.     

Introduction of Raikhanim (Ficus semicordata) in a Maize and Finger-Millet Cropping System: An Agroforestry Intervention in Mid-Hill Environment of Nepal

Fodder trees are integral part of farming system in the hills of Nepal, but designed agroforestry interventions targeted to particular trees and crops are not widely available. This paper examines the joint productivity of an agroforestry practice in which Raikhanim (Ficus semicordata) is planted in a maize (Zea mays) and finger-millet (Eleusine coracana) cropping system at Keware Bhanjyang of the western mid-hills of Nepal. Raikhanim seedlings were planted in a row on terrace risers 2, 4 and 6 m apart in ordinary farming conditions, in a randomized block design with three replications. Maize and finger-millet were grown on the terraces as intercrops with a control plot without trees on risers in each replicate. Growth parameters of Raikhanim—height, diameter at 30 cm above ground (D₃₀) and survival rate—were recorded annually in December until trees were lopped for fodder biomass, and crop yields were measured to determine tree-crop interaction effects. Tree height and D₃₀ differed significantly between spacings until trees reached the lopping stage 3½ years after planting, with the highest growth in 4 m spacing. Tree lopping checked the height growth but the diameter growth continued to increase and differed among spacings after lopping. Fodder biomass increased with tree age and was highest under 4 m spacing (7.294 t/ha) followed by 6 m (5.256 t/ha) and 2 m (3.84 t/ha). Finger-millet yield in the experimental plots decreased with tree age due to shading effects, while maize yield was not substantially affected. Among spacings, control plots produced the highest finger-millet yield (1,624 kg/ha) while the 6 m spacing produced the highest maize yield (2,463 kg/ha). It is concluded that planting Raikhanim at 6 m intervals will produce additional fodder without significant effect on maize yield and only a moderate effect on finger-millet yield. The agroforestry practice of planting fodder trees on under-utilised terrace risers is a viable option for mid-hill farmers for simultaneous production of fodder and cereal crops while sustaining the hill farming system.     

半干热石质山地墨西哥柏伴生树种选择研究

在云南省开远市浑水塘试验地设置了35个20 m×20 m的标准地,对标准地内4 a生的主要造林树种墨西哥柏及4个供选伴生树种（羽叶山黄麻、新银合欢、直干桉、赤桉）地径、树高、胸径、冠幅分别进行测量,选择平均木,对平均木生物量、生长量进行测定.经数据分析后认为,新银合欢生长速度慢于墨西哥柏且枝少叶疏,适宜作为墨西哥柏的伴生树种,羽叶山黄麻冠幅虽大,但枝叶稀疏,可作为墨西哥柏的次适宜伴生树种.     

Relationships between crown projected area and components of above-ground biomass in Norway spruce trees in even-aged stands: Empirical results and their interpretation

Sample tree material was reanalyzed in order to study the relationships between horizontal crown projected area and components of above-ground biomass in Norway spruce (Picea abies (L.) Karst.) trees growing in even-aged stands. The needle mass of dominant trees increased linearly with the increase in crown projected area, but in co-dominant and dominanted trees the increase in needle mass levelled off toward larger crown projected areas. The branch mass of dominant and co-dominant trees accumulated faster than linearly with increasing crown projected area, whereas in dominated trees an approximately linear relationship existed between these two variables. The increase in needle and branch mass per unit increase in crown projected area was highest in dominant trees and decreased to co-dominant and dominated trees, i.e. with tree position in the canopy. The stem mass accumulated obviously faster than linearly and similarly in all tree classes with the increase in crown projected area. The narrow crown shape indicated a high density of all components of above-ground biomass per unit of crown projected area.     

Crown transparency, tree mortality and stem growth of Pinus sylvestris, and colonization of Tomicus piniperda after an outbreak of Gremmeniella abietina

In the year 2000, large areas of forest in Sweden, mainly 30-50 year old Pinus sylvestris (L.) stands, were attacked by the fungus Gremmeniella abietina (Lagerb.) Morelet. The aims of this study were to investigate: (i) the relationship between G. abietina-induced tree crown transparency (CT) and P. sylvestris (L.) tree mortality; (ii) the influence of CT levels on stem growth; (iii) the recovery of the crown; and (iv) the association of CT and colonization by Tomicus piniperda (L.). Thirty-five permanent sample plots were established in five P. sylvestris stands (38-46 years old), infested by G. abietina, and 23 plots in four reference stands, not obviously infested.During the 5 years following the attack, the total mortality amounted to 454 trees ha⁻¹ and 7.8 m² ha⁻¹, on average, in the five infested stands, corresponding to 42% of the trees and 34% of the basal area at the time of the attack. Most of the mortality occurred within 2 years of the attack. The mortality of individual trees (2002-2005) was found to be related to the crown transparency (CT), the position of needle loss within the crown and the tree diameter at breast height. Based on our modeling, the probability of mortality was substantially increased if the initial CT-value was higher than 85%.Growth reductions were detected for individual trees with an initial CT of >c. 40%. In contrast, trees with a low initial CT (<c. 40%) were not affected and even exhibited increased growth. In the five infested stands, the reductions in basal area and volume increment were estimated to be 26-58%, and, 42-73%, respectively, during the five growing seasons after the attacks.The trees in the infested stands that were still alive in spring 2005 had started to recover in terms of CT. Breeding of T. piniperda on the P. sylvestris (L.) stems occurred almost exclusively on stems with a CT > 90%.The data from this study suggest that when a P. sylvestris (L.) stand has been attacked by G. abietina, trees with a CT above 80% should be felled; the remaining trees will have a high probability of survival and resistance to successful breeding by the T. piniperda.     

Open-pollinated, interspecific F1 hybrid seed orchards of Leucaena: I. Rootstock effects

Seed orchards of Leucaena were established at two experimental sites in Hawaii to produce either triploid or tetraploid interspecific hybrid seed by interplanting clonal self incompatible diploid (L. diversifolia, L. esculenta) or tetraploid (L. pallida) species with self- compatible L. leucocephala lines and the F1 hybrid of L. diversifolia (2n = 4x) × L. leucocephala. The seed parents were grafted onto three seedling rootstocks (L. diversifolia (2n = 4x), shrubby L. leucocephala, and giant L. leucocephala) to compare rootstock effects on scion growth. This paper reports on the effects of rootstock on scion growth during the first year based on total truck cross sectional area, height growth, and crown habit. In the triploid seed orchard, rootstock significantly affected the growth of four of the six clones, while in the tetraploid orchard the growth of two of the five clones was significantly affected by rootstock. Crown habit was independent of rootstock. Our study suggests that rootstock effects depend on the specific scion and rootstock combination, and site. This revised version was published online in June 2006 with corrections to the Cover Date.     

Sequence characterized amplified region (SCAR) analysis on DNA from the three medicinal Echinacea species

In our previous study, RAPD (Random Amplified Polymorphic DNA) analysis revealed species-specific markers for three medicinal Echinacea species (Asteraceae): E. angustifolia DC., E. pallida (Nutt.) Nutt. and E. purpurea (L.) Moench. In the present work, we have converted a RAPD marker (750 bp) for E. purpurea into a SCAR (Sequence Characterized Amplified Region) marker. SCAR-PCR, in fact, revealed the expected amplicon (330 bp) only in E. purpurea and not in the other two species, giving further evidence for differences in medicinal Echinacea spp. genome and confirming a greater similarity between E. pallida and angustifolia.     

A novel flavone glycoside from the stem of Bauhinia purpurea.

A novel flavone glycoside, 5,6-dihydroxy-7-methoxyflavone 6-O-beta-D-xylopyranoside (1) was isolated from the chloroform-soluble fraction of the ethanolic extract of Bauhinia purpurea stems.     

Growth Parameters and Nutrient Content in Four Multipurpose Tree Species with Potential Characteristics for Agroforestry Systems in a Cerrado Region in Botucatu,São Paulo State,Brazil

Abstract

In order to evaluate growth characteristics, adaptability, biomass production, nutrient recycling, nutrient distribution and the ability to regenerate degraded land, a trial using four multipurpose tree species (Leucaena leucocephala, Leucaena diversifolia, Acacia melanoxylon and Mimosa scabrella) was undertaken over two years in a distrophic red yellow latosol (oxisol) following a randomized block experimental design with four replications.

At the age of two years, A. melanoxylon and L. diversifolia were the tallest species (5.25 and 4.97 m, respectively) and A. melanoxylon and M. scabrella had the largest diameters at 20 cm from tree base.

Mimosa scabrella and A. melanoxylon had the highest dry matter production and quantity of nutrients in the above ground biomass. In all species, the highest nutrient contents were found in the leaves, followed by branches and stems. From all species, the highest Nutrient Utilization Efficiency Indexes were obtained for sulphur, phosphorous, and magnesium; L. diversifolia was the most efficient for nitrogen, potassium, calcium, sulphur, and manganese, while A. melanoxylon was the most efficient for phosphorus, magnesium, boron, iron, and zinc. Litter production levels over a three month period were as follows: M. scabrella > A. melanoxylon > L. diversifolia > L. leucocephala. Litter nutrient content was higher in M. scabrella than in the other species.     

广州城市绿地乔木种类及生长状况调查

在广州市天河区、越秀区、荔湾区、番禺区、海珠区等地选定46块面积为400 m2的标准地进行城市绿地调查,主要调查样地实际用途、样地地面覆盖信息,乔木树高、胸径、冠下高、冠幅、生长状况(包括主要病虫害)等信息,并对各样地及乔木调查数据进行分析。结果表明,46块样地共有乔木408株,涉及树种64种;应用频率较高的3个树种依次为小叶榕、垂叶榕、高山榕,其应用频率总和占总频率的67.5%;小叶榕、白兰、樟树、塞楝、红花羊蹄甲等乔木长势较好,其他树种长势一般;道路绿地树种长势较好,城市公园其次,街头绿地次之。     

4种阔叶树在从化生态景观林带中的早期生长表现

2005年在广东省广从公路从化温泉段两侧营建生态景观林带,种植山杜英（Elaeocarpus sylvestris）、黎蒴（Castanopsis fissa）、枫香（Liquidambar formosana）和凤凰木（Delonix regia）4种阔叶树。造林后调查树种保存率、高生长、胸径生长和树冠生长。结果表明：2a生时,枫香、山杜英、凤凰木的造林保存率均超过96％,黎蒴相对较低,为94．4％;3a生时,3个生长性状在树种间与种植坡位间均存在显著差异。树种生长快慢次序为黎蒴〉山杜英〉枫香〉凤凰木,生长最快的在山坡下部,其次是山坡中部,最慢是山坡上部。黎蒴、山杜英和枫香主干清晰,树形和叶色美观,是适宜的景观树种;凤凰木丛生现象突出,树形不佳,不宜种植在山地。     

Interannual consistency in canopy stomatal conductance control of leaf water potential across seven tree species

We investigated interannual variability of canopy transpiration per unit ground area (E (C)) and per unit leaf area (E (L)) across seven tree species in northern Wisconsin over two years. These species have previously been shown to be sufficient to upscale stand-level transpiration to the landscape level during one growing season. Our objective was to test whether a simple plant hydraulic model could capture interannual variation in transpiration. Three species, wetland balsam fir (Abies balsamea (L.) Mill), basswood (Tilia Americana L.) and speckled alder (Alnus rugosa (DuRoi) Spreng), had no change in E (C) or E (L) between 2000 and 2001. Red pine (Pinus resinosa Ait) had a 57 and 19% increase in E (C) and E (L), respectively, and sugar maple (Acer saccharum Marsh) had an 83 and 41% increase in E (C) and E (L), respectively, from 2000 to 2001. Quaking aspen (Populus tremuloides Michx) had a 50 and 21% decrease in E (C) and E (L), respectively, from 2000 to 2001 in response to complete defoliation by forest tent caterpillar (Malascoma distria Hüber) and subsequent lower total leaf area index of the reflushed foliage. White cedar (Thuja occidentalis L.) had a 20% decrease in both E (C) and E (L) caused by lowered surface water in wetlands in 2001 because of lower precipitation and wetland flow management. Upland A. balsamea increased E (L) and E (C) by 55 and 53%, respectively, as a result of release from light competition of the defoliated, overstory P. tremuloides. We hypothesized that regardless of different drivers of interannual variability in E (C) and E (L), minimum leaf water potential would be regulated at the same value. Minimum midday water potentials were consistent over the two years within each of the seven species despite large changes in transpiration between years. This regulation was independently verified by the exponential saturation between daily E (C) and vapor pressure deficit (D) and the tradeoff between a reference canopy stomatal conductance (G (S)) and the sensitivity of G (S) to D, indicating that trees with high G (S) must decrease G (S) in response to atmospheric drought faster than trees with low G (S). Our results show that models of forest canopy transpiration can be simplified by incorporating G (S) regulation of minimum leaf water potential for isohydric species.     

Analyses of stand structure as a tool for silvicultural decisions — a case study in a Quercus petraea — Sorbus torminalis stand

The study applies structural indices using the example of an oak (Quercus petraea (Matt.) Liebl.) — chequer tree (Sorbus torminalis (L.) Crantz) stand in order to derive recommendations for the silvicultural treatment of Chequer trees. The investigated stand, located in the northern part of Bavaria, comprises eight tree species and four shrub species. Various indices were used to analyse the stand structure and the crown coverage frequency. It was shown that chequer trees, which are presently of high economic interest, are strongly oppressed in the upper layer and almost completely missing in the lower layers of the stand. The possible reasons for this finding and alternatives for the further management of the stand are discussed. Persistent and repeated thinnings in order to ensure sufficient crown development of the chequer trees seem to be essential for their survival.     

Determinants of drought effects on crown condition and their relationship with depletion of carbon reserves in a Mediterranean holm oak forest

Severe droughts may increase physiological stress on long-lived woody vegetation, occasionally leading to rapid defoliation and progressive increase in mortality of overstorey trees. Over the last few years, episodes of drought-induced tree dieback have been documented in a variety of woodlands and forests around the world. However, the factors determining tree survival and subsequent recovery are still poorly understood, especially in resprouter species. We have studied the effects of a single drought episode on crown condition in a holm oak (Quercus ilex L.) forest located in NE Spain 7 years after the drought event. Generalized linear models were used to study the environmental correlates of forest crown condition 7 years after the drought event. Additionally, we evaluated the association between crown condition and the carbon and nutrient reserves stored in lignotubers 7 years after the drought. Our study reveals the multifactor nature of a drought-driven forest dieback in which soil depth and the characteristics of individual trees, particularly their number of stems, determined a complex spatial pattern of tree-level responses. This dieback was associated with a depletion of the carbon reserves in lignotubers 7 years after the episode, representing a reduction of up to 60% in highly drought-damaged trees. Interestingly, in the absence of new acute droughts, successive surveys in 2007-11 showed a direct association between carbon reserves depletion and further deterioration of crown condition. More frequent droughts, as predicted by climate change projections, may lead to a progressive depletion of carbon reserves and to a loss of resilience in Mediterranean resprouter species.     

Wheat growth as influenced by application of agroforestry-tree prunings in Ethiopian highlands

The response of wheat (Triticum aestivum cv. Enkoy) to application of leaf prunings of nine agroforestry-tree species was investigated in a field trial and a six-week pot trial. The tree species were Grevillea robusta, Erythrina abyssinica, Gliricidia sepium, Albizia schimperiana, Acacia nilotica, Acacia polyacantha, Leucaena leucocephala, Leucaena pallida and Entada abyssinica. L. leucocephala, L. pallida, G. sepium and Entada abyssinica proved to be good pruning sources in the pot trial. G. robusta, A. polyacantha, A. nilotica and E. abyssinica had adverse effects on wheat seedlings with increased pruning loads probably due to immobilization processes or allelopathic effects. N and lignin content, C/N ratio, lignin/N ratio, phenolics/N ratio and (phenolics + lignin)/N ratio of the pruning material were all significantly correlated with shoot dry matter production of the wheat seedlings. With the exception of Entada abyssinica, which performed well under field conditions, a similar ranking as in the pot trial was established in the field experiment, but at harvest differences were not as pronounced as in the pot trial. Gliricidia treated wheat produced by far the highest grain yield with 248 g/m².This revised version was published online in November 2005 with corrections to the Cover Date.