Micropropagation of an endangered Indian sandalwood (Santalum album L.)

Santalum album is known as East Indian sandalwood. It is the most economically important tree harvested for heartwood oil, and India is among the chief exporters of sandalwood and its products. Multiple shoots were induced from nodal shoot segments derived from a 50- to 60-year-old candidate plus tree (CPT) on Murashige and Skoog (MS) medium supplemented with 0.53 μM α-naphthaleneacetic acid (NAA) and 11.09 μM 6-benzylaminopurine (BA). In vitro differentiated shoots were multiplied on MS medium with 0.53 μM NAA, 4.44 μM BA, and additives: 283.93 μM ascorbic acid, 118.10 μM citric acid, 104.04 μM cystine, 342.24 μM glutamine, and 10% (v/v) coconut milk. New shoots were harvested repeatedly for up to three subculture passages on fresh medium at 4-week intervals. Microshoots treated with 98.4 μM indole-3-butyric acid (IBA) for 48 h produced roots on growth-regulator-free, quarter-strength MS basal salts medium with vitamin B₅ and 2% sucrose. In vitro root induction was achieved from microshoots pulsed with 1230 μM IBA for 30 min in soilrite rooting medium. The percentage of rooting in soilrite was higher than that for agar medium, and in vitro raised plants were established in the field and showed normal growth.     

Effects of different culture media on the growth of Indian sandalwood (Santalum album L.) seedlings in Zhanjiang, Guangdong, southern China

We studied the effects of different culture media on the growth of India sandalwood (Santalum album L.) seedlings in Zhanjiang, Guangdong Province in southern China. Five different growth substrates, lateritic subsoil, burnt soil, agricultural soil, peaty soil and coconut dust, were used as the basic culture materials and seven different treatments of composition were used as potting media. Kuhnia rosmarinifolia Vent. was used as a primary host plant for all treatments. Statistically significant differences were found between treatments in respects of survival rate (p < 0.001), height (p < 0.001), ground diameter (p < 0.001) and biomass (p = 0.002), as well as for quality index (p = 0.001) of S. album seedlings after 6-month growth in containers with different culture media. Among all treatments, the treatment combining burnt soil, peat and coconut dust in a weight ratio of 1:1:1 plus 2% calcium super-phosphate as basal manure achieved the best performance for most of the seedling growth parameters, including survival rate (98%), height (35.81 cm), ground diameter (0.56 cm), biomass (4.46 g) and quality index (0.65), followed by the treatment using only burnt soil plus 2% calcium super-phosphate as the culture medium (survival rate 86%, height 29.23 cm, ground diameter 0.48 cm, biomass 3.36 g and quality index 0.52), while the treatment using only lateritic subsoil plus the basal manure as the medium obtained the poorest results in survival rate (38%), height (12.04 cm), ground diameter (0.19 cm), biomass (0.26 g) and quality index (0.043). Increasing the proportion of lateritic subsoil in the medium when mixed with peat and coconut dust did not show statistically significant differences in survival, height, ground diameter, biomass nor in quality index. In consideration of cost, using burnt soil plus 2% calcium super-phosphate as basal manure may be the optimum culture medium for large-scale production of Indian sandalwood seedlings in Guangdong, southern China.     

Effects of different culture media on the growth of Indian sandalwood （Santalum album L.） seedlings in Zhanjiang, Guangdong, southern China

We studied the effects of different culture media on the growth of India sandalwood(Santalum album L.) seedlings in Zhanjiang,Guangdong Province in southern China. Five different growth substrates,lateritic subsoil,burnt soil,agricultural soil,peaty soil and coconut dust,were used as the basic culture materials and seven different treatments of composition were used as potting media. Kuhnia rosmarinifolia Vent. was used as a primary host plant for all treatments. Statistically significant differences were f...     

Desmanthus virgatus (L.) Willd. An Efficient Intermediate Host for the Parasitic Species Santalum album L. in Timor,Indonesia

In cultivation, sandalwoods suffer high seedling losses both in the nursery and when transplanted to the field. It was hypothesised that early haustorial connection to an efficient pot host should enhance growth and survival in both nursery and field. Nursery performance of Santalum album was contrasted with a range of species as initial- or nursery-stage hosts for plantation establishment in Timor. With pot-hosts of Desmanthus virgatus, Crotalaria juncea L. or Alternanthera cv., sandalwood grows rapidly to a mean height > 25 cm at < 26 weeks from sowing. These species are superior pot-hosts to the traditional Capsicum frutescens L. Subsequent field performance over 4 years is best with those sandalwoods initially hosted to D. virgatus. This species has the capacity to function as both a pot-host and an intermediate field-host for sandalwood. We conclude that for Timor conditions, sandalwood should be preferentially grown with D. virgatus as the first-stage, or in-pot, host plant species.     

Competition for light, water and nitrogen in an association of hazel (Corylus avellana L.) and cocksfoot (Dactylis glomerata L.)

Competition for light, water and nitrogen between hazel trees and cocksfoot grown under the trees was studied in two hazel plantations managed in different ways. The first plantation with a light transmission of at least 70% at grass level was compared with two control hazel and cocksfoot monocrops. The soil was a calcareous heavy clay, 1.4 m deep. Water stress during summer was severe in the intercropped stand as well as the grass- only plots, while it was much less in the sole stand of trees (without grass). Hazel tree water potential in the intercropped stand improved in the fourth year as the trees extended their roots similarly to the grass-free ones, despite their much lower canopy growth rate. The fourth year, local N fertilisation began to be effective as evidenced by the N content per leaf area unit and growth of the intercropped trees: grass root competition was high and root barriers were needed to exclude it. The second plantation was managed on a deep soil with a water table at approximately 2.5 m depth. The trees did not suffer from the presence of grass, and allowed a 15 to 75% light transmission rate. A control monocropped grass plot was established for comparison. On the basis of the multiple limitation hypothesis, a grass dry matter production model was built which accounts for radiation transmitted to the understorey, water supply, temperature and air moisture deficit in interaction with the radiation transmission rate (r2 = 0.716; 590 observations). The limits of such models are discussed with regard to insufficient knowledge on root dynamics. This revised version was published online in June 2006 with corrections to the Cover Date.     

Regeneration ecology and population status of a critically endangered and endemic tree species （Ilex khasiana Purk.） in north-eastern India

Detailed studies on population structure and regeneration ecology of Ilex khasiana were carried out at five representative natural populations i.e. Mylliem (Population - I), Upper Shillong (Population - II), Shillong Peak (Population - III), Laitkor (Population - IV) and Nongpiyur (Population - V) to probe into the responsible affecting factors for its population structure and regeneration ability in these populations. Experimental observation under three controlled light conditions (full sunlight (100%), intermediate sunlight (50%) and low sunlight (30%)) showed that the growth status and survival rates of seedlings under intermediate and low light were better than those under the high light condition. The density-diameter distribution in population of adult trees (≥5cm dbh) exhibited a typical character of a regenerating population. A higher seedling mortality rate in natural populations of I. khasiana was most probably due to increase in light intensity following vegetation destruction and other anthropogenic disturbances that cause opening of forest canopy. The findings of the present study would be of immense value in formulating appropriate conservation measures for the species.     

印度东北地区一种极频危和特有树种(Ilex khasiana Pork.)再生生态学及种群现状

在5个典型自然种群Mylliem(种群1)、Upper Shillong(种群2)、Shillong Peak(种群3)、Laitkor(种群4)和Nongpiyur(种群5)中,详细研究了冬青树(Ilex khasiana)种群结构和再生生态学,旨在探究种群结构和再生能力的影响因素.在全光照(100%),中等光照(50%)和低光照(30%)三种光强度条件下,实验观察表明:在中等和低光照条件下的种苗成活率和生长状态好于在高光照条件下的种苗成活率和生长状态.成年树种群(≥5cm dbh)的密度直径分布揭示了一种再生种群的典型特征.对植被的破坏和人类其他干扰导致森林树冠疏开使光照增强,造成自然种群(L khasiana)幼苗的高死亡率.本研究结果对制定适当的物种保护措施有重要价值.     

Black locust (Robinia pseudoacacia L.) as a multi-purpose tree species in Hungary and Romania: a review

Black locust(Robinia pseudoacacia L.) was the first North-American tree species imported to Europe at the beginning of the seventeenth century. It is commonly planted worldwide because of its adaptability to environmental stresses, its valuable wood, easy propagation, frequent and abundant seed production, excellent coppicing,high seedling survival, and relatively high wood yield. In Europe, Romania and Hungary have the most highly-developed black locust growing techniques and experiences.As a result of increasing interest in black locust in many countries, this review aims to provide a comprehensive overview of state-of-the-art site requirements, propagation, improvement and management(including growth and yield as well as use in energy plantations).     

The process of decline of an endangered tree species,Pinus armandii Franch. var.amamiana (Koidz.) Hatusima, on the southern slope of Mt. Hasa-dake in Yaku-shima Island

The process of decline of an endangered tree species,Pinus armandii var.amamiana, was monitored on the southern slope of Mt. Hasa-dake in Yaku-shima Island from 1994 to 1998. There are 163 trees ofP. armandii var.amamiana over 1.3 m in height. They are distributed on steep ridges and rocks with a thin soil layer mostly consisting of friable granite. During the monitoring period, 21 trees ofP. armandii var.amamiana died and the mortality rate was 12.9%. Dead trees were categorized into three types: standing, uprooted and landslide. The uprooted- and landslide-typed dead trees were found only after a severe typhoon struck Yaku-shima Island. This suggests that the combination of fragile site conditions and severe typhoons play an important role in the process of decline ofP. armandii var.amamiana. The standing-typed dead trees were presumed to have been killed by pine wilt disease, accounting for 71.4% of the dead trees. However,Bursaphelenchus xylophilus, the cause of pine wilt disease, was not detected from any of the wood chips or branch samples from the standing-typed dead trees ofP. armandii var.amamiana. This might indicate that some factor(s) other than pine wilt disease could be responsible for the standing-typed death ofP. armandii var.amamiana in natural habitats. A part of this paper was presented at the 109th Meeting of the Japanese Forestry Society.     

Preservation of Juniperus thurifera L.:a rare endangered species in Algeria through in vitro regeneration

Juniperus thurifera L.is an endemic Cupres saceae from the Aure`s Mountains of north eastern Algeria and endangered,in part,due to the scarcity of viable seeds It is threatened by other abiotic factors and the lack of an effective management strategy will increase its risk o extinction.The dearth of information on its in vitro regeneration impedes its application in forest managemen programs.We therefore developed a micropropagation protocol using microcuttings with auxiliary buds.Cuttings were grown on different combinations of media supplemented with plant growth regulators at different concentrations.The highest number of shoots and branches regenerated from original shoots was obtained on Woody Plant Medium(WPM)supplemented with 6-benzylaminopurine(BAP)(0.5 mg L^-1)and 2,4-dichlorophe noxyacetic acid(2,4-D)(0.25 mg L^-1).The best elongation of shoots was achieved with WPM supplemented with0.5 mg L^-1of BAP and 0.25 or 1 mg L^-1 of 2,4-D.On the second subculture,shoots had a higher number of branches than those of the first.The highest rooting rate,38.8%,was obtained with shoots cultured in 1/2 Murashige and Skoog(MS)medium supplemented with 5.0 mg L^-1each of indol-3-butyric(IBA)and naphthalene acetic acid(NAA).Similarly,the highest root numbers and lengths were produced on 1/2 MS medium supplemented with IBA and NAA(5.0 mg L^-1each).During transfer to acclimatization,rates of plant losses of 50% occurred.The second part of the experiment showed that the best shoot callusing was on WPM supplemented with BAP and 2,4-D,with either the combination 0.5+0.25 or 0.25+0.25 mg L^-1.The results of this research provide a starting point for further studies on in vitro regeneration of J.thurifera for the sustainable management of its unique ecosystem in the Mediterranean basin.     

A population genetic study in a scattered forest species, wild service tree [Sorbus torminalis (L.) Crantz], using RAPD markers

Wild service tree [Sorbus torminalis (L.) Crantz] is a forest tree widespread in Europe, characterized by a scattered distribution. Its hermaphroditic flowers are pollinated by insects, and outcrossing is the prominent mating system, also due to the presence of gametophytic self-incompatibility. Genetic diversity and differentiation of 22 populations from northwestern Italy were investigated by means of variation scored at 53 polymorphic RAPD (Random Amplified Polymorphic DNA) loci. Populations differed in genetic variation, with Shannon diversity index ranging from 0.166 to 0.469. According to Analysis of Molecular Variance (AMOVA), most of the genetic variation was found within populations (61.78%) with a significant proportion of variance attributable to genetic differences between regions (23.60%) and between populations (14.62%). Evidence for isolation by distance was found in the set of populations sampled. The effect of habitat fragmentation on genetic variation was also evaluated. The efficacy of RAPD markers in analysing genetic variation, and the contribution of the results in terms of the preservation of biodiversity are discussed.     

Factors influencing establishment by direct seeding of indigenous tree species in typical plantations and shrubland in South China

Seed limitation of desired indigenous species has constrained the succession of established plantations from an early successional stage, to more natural forests in South China. Because of its low cost and time-saving advantages, direct seeding has been considered a useful method in forest regeneration. To improve our understanding of whether and how direct seeding can lead to the establishment of indigenous tree species, we carried out an experiment in four typical plantations (eucalyptus, mixed-native, mixed-legume, mixed-conifer) and a shrubland in South China. We also tested the effect of understory vegetation and litter removal on seedling establishment and growth. Seeds of three indigenous tree species (Castanopsis chinensis, Cryptocarya chinensis, and Psychotria rubra) were sown with understory vegetation and litter either retained or removed. Seedling emergence, survival, and growth were recorded for 21 months. We found that conditions that favored seedling emergence often differed from those that favored seedling survival. While the removal of understory vegetation and litter did not influence the final seedling establishments for all the three introduced species, growth of Psychotria rubra was influenced at several sites. Seed mass was positively correlated with seedling emergence and subsequent growth. The large-seeded Castanopsis chinensis showed higher emergence and growth than the intermediate-seeded Cryptocarya chinensis or the small-seeded Psychotria rubra. Seedlings of Castanopsis chinensis grew better in plant communities with high understory light penetration and high soil exchangeable potassium. Growth of P. rubra seedlings decreased significantly with soil hydrolyzed nitrogen. In conclusion, direct seeding can be useful for the establishment of indigenous tree species into plantations and shrubland. Optimizing early seedling establishment and growth will require the selection of suitable native species for improving seedling establishment in different plantations. Additionally, understory vegetation and litter and fertilizer should be properly managed to enhance the establishment of certain indigenous tree species.     

Diversity of the calabash tree (<Emphasis Type="Italic">Crescentia cujete</Emphasis> L.) in Colombia

Germplasm of the calabash tree (Crescentia cujete L.) was collected in five major regions of Colombia, i.e. the Andes, Caribbean, Amazon, Orinoco, and Pacific regions. Collecting this multipurpose tree was guided by the indigenous knowledge of farmers and artisans in each region. Large variation in fruit shapes and sizes was found, of which some forms were typical for certain regions. Overall 56 accessions were collected and roughly classified into 22 types by eight fruit shapes and eight sizes. Molecular markers (Amplified fragment length polymorphisms) were applied to leaf tip tissue originating from vegetatively propagated plants in order to assess the diversity available in the germplasm collected as well as to detect patterns of geographical or morphological similarity. One accession each of C. alata H.B.&K. and C. amazonica Ducke were used as outgroups. Overall, genetic diversity was high (mean Nei and Li’s coefficient of 0.43). No relations could be established between either geographical provenance or fruit morphology and patterns of genetic diversity. Concerning the outgroups, the C. amazonica accession appeared to be a distinct species. The C. alata accession, however, did not seem to be sufficiently distinct from C. cujete to merit species status. The latter material may in fact be a hybrid or serve to challenge the validity of interspecific organization of the genus Crescentia.

安化县珍贵树种资源培育现状与建议

介绍了安化县近些年来珍贵树种资源现状及取得的成效,并从加强领导、政策配套、科技支撑、价值宣传、创新机制、优惠扶持等方面总结了安化县珍贵培育工作取得的经验,最后针对安化县珍贵树种发展过程中存在的一些问题提出相应建议。     

High-pruning of European beech (Fagus sylvatica L.) and pedunculate oak (Quercus robur L.): work efficiency for target pruning as a function of tree species,pruning height,branch characteristics,pole saw type and operator

The objective of this study was to establish an operational model of productive work time per tree (work efficiency) for high-pruning of young European beech and pedunculate oak depending on tree species, pruning height, branch characteristics, pole saw type and operator. The final model included all of these independent variables with branch characteristics specified in terms of number of live branches and cross-sectional area of the thickest branch at the cut. Work time increased with increasing values of each of the three numeric variables. For a given pruning height the size of the largest branch was for all practical purposes more influential than the number of live branches. Beech took 28% longer to prune than oak. The German Ergo-Schnitt saw was 21% slower than the Japanese Silky Hayauchi saw. The variation in worker performance within our study was larger than that attributed to tree species and pruning equipment.     

木荷等6种阔叶树种光合生理特性比较

在东江中上游,对6年生木荷、红锥、火力楠、藜蒴、灰木莲和枫香的净光合速率（Pn）、蒸腾速率（Tr）、水分利用效率（WUE）等生理生态指标开展观测研究,结果表明：8月,6种树种均表现较强的生活力,保持了较高的净光合速率与蒸腾速率;10月,6树种均通过降低光合、蒸腾和提高水分利用效率来适应逆境。8月平均Pn和Tr要比10月均值分别高71.86%和129.22%,10月WUE却要比8月均值高25.78%。6树种Pn、WUE的平均值高低排序,均表现为木荷〉红锥、藜蒴和火力楠〉枫香和灰木莲,说明木荷有较强的环境适应能力和抗旱能力,其次为红锥、火力楠和藜蒴,而灰木莲和枫香较低。     

Impact of land-use type and bark- and leaf-harvesting on population structure and fruit production of the baobab tree (Adansonia digitata L.) in a semi-arid savanna,West Africa

Non-timber forest products (NTFPs) strongly contribute to livelihood security in the semi-arid tropics. There is increasing concern about the population status of NTFP-providing trees and therefore a need for their sustainable use. Thus, this study examines the impact of land-use type on the multipurpose baobab tree (Adansonia digitata L.) in Burkina Faso, combined with rates and patterns of bark- and leaf-harvesting, and their impact on fruit production. We compared stands in a protected area (W National Park of Burkina Faso) with those of surrounding communal area (fallows, croplands and villages) to obtain an indication on the status of the baobab population, to assess its harvesting tolerance and to estimate to what extent their actual use is sustainable. Our results reveal that land-use type has an impact on the population structure of the baobab. The size class distribution curve of park stands was inverse J-shape which indicates good rejuvenation, while the curve of fallows, croplands and villages stands was bell-shaped, indicating a lack of recruitment. However, a high number of seedlings were recorded in villages. Nearly all baobabs were pruned and debarked in villages, croplands and fallows while half of the individuals were harvested in the park. Most of the trees were pruned and debarked moderately. Debarking and pruning were slightly size specific. Pruning in interaction with tree-size had a significant impact on fruit production. In contrast, debarking had no effect on fruit production. We conclude that despite the land-use impact and the intense harvesting, baobabs are still well preserved in the communal area due to their longevity, extremely low adult mortality rates and traditional management practices. However, land-use intensifications may lead to increasing pressure on baobab populations in the future. Therefore, adapted management strategies are needed to guarantee the persistence of this important species and to avoid a shortage of baobab products.     

Physiology and genetics of tree growth response to moisture and temperature stress: an examination of the characteristics of loblolly pine (Pinus taeda L.)

Water stress and temperature impose fundamental limits to forest productivity. Stresses caused by fluctuating or extreme temperatures or limited water availability vary both seasonally and from year to year. The role of these stresses should be considered when investigating the causes of declines in forest productivity. Forest growth, or carbon gain, can be related quantitatively to three components: leaf area, rate of net photosynthesis and rate of respiration. This paper examines effects of temperature and water supply on these components with particular reference to loblolly pine (Pinus taeda L.), a species of economic importance in the southeastern United States where declines, of unknown cause, in forest productivity have been reported.