The role of indigenous trees for the conservation of biocultural diversity in traditional agroforestry land use systems: The Bungoma case study: In-situ conservation of indigenous tree species

In order to precisely assess the role of agroforestry for the conservation of (agro-)biological diversity there is a need to adjust sampling methods used in plant sociology. This study is on the contribution of agroforestry land use to the in-situ conservation of indigenous trees within a typical East-African smallholder farming system in Western Kenya. A modified approach to measuring species richness and abundance is presented. The selection of tree-rich structures was done according to management patterns rather than considering syntaxonomic classifications from the vegetation science point of view. This approach, which is better suited to the strongly human-influenced vegetation of agroecosystems, employs between-management unit diversity measures to help evaluate abundance and constancy of species in particular management units. The predominant off-farm vegetation patterns are riverine forests, rocky hillsides, hedgerows, wooded grassland relicts, woodlands or colline forest relicts and tree groves whereas the noticeable tree-rich on-farm management units are homegardens, homesteads, life fences, coffee- and banana-groves and annual cropping fields. 98% out of all indigenous tree species known from Bungoma, occur in off-farm lands. 53% of the indigenous tree species occur in tree rich on-farm management units while 47% of the indigenous trees are dependent on the maintenance of off-farm lands. Hedgerows embody the most promising secondary vegetation structure that shows ample potential to accommodate a wide range of indigenous perennial species outside the natural vegetation formations. The pattern of distribution of various vegetation structures, and the mixture with diverse tree-based on-farm plots are interesting features in regard to floristic and eco-diversity on a landscape level. In this respect, three areas that show different population densities and distinct agro-historical conditions were compared. In regions of particular high population density the degree of association of various functional land use forms and woodland structures – each characterised by its own floristic make-up – is comparatively high. In contrast, in regions with less population but that were settled at a later date, one encounters fewer stands of woody plants with lower numbers of species. This revised version was published online in June 2006 with corrections to the Cover Date.     

Genetic differentiation and diversity of Adansonia digitata L (baobab) in Malawi using microsatellite markers

Baobab (Adansonia digitata L) belonging to Bombacaceae family, is one of the most widely used indigenous priority tree species in sub-Saharan Africa, valued in the cosmetic industry for its seed oil, and powdery fruit pulp for juice making. Baobab has high potential for domestication in southern Africa, therefore understanding its genetic diversity and population structuring is warranted. The study investigated the level of genetic diversity and differentiation of five populations of A. digitata L. sampled from four diverse silvicultural zones in Malawi. Variation at nine microsatellite loci were examined in 150 individual trees. Low mean genetic diversity was expressed through genetic diversity indices: Nei’s genetic diversity (h, 0.18 ± 0.03), Shannon Information Index (I, 0.21 ± 0.07), observed number of alleles (na, 1.47 ± 0.10), effective number of alleles (ne, 1.23 ± 0.04) and percentage polymorphic loci (pp, 48 %). The low genetic variation found is attributed to the population growing in marginal areas of genetic centre of diversity of the species, anthropogenic factors and founder effects. Moderate genetic differentiation was observed among populations (Gst = 0.13) indicating the presence of a large number of common alleles resulting in a homogenisation effect. Clustering of individual trees by genetic similarity coefficients indicated that mainland trees were genetically closer than the trees on Likoma Island. Mantel’s test showed a weak positive insignificant correlation (Z = 0.12; P = 0.64) between genetic distance among populations and actual distance on the ground implying that geneflow was not directly influenced by isolation by distance. The results suggest that seed distribution and tree improvement should recognise the presence of ecotypes and conservation measures should protect all the populations due to existence of private alleles which are of adaptive importance.     

粤东100种乡土树种分析评价

通过实地调查和对文献资料的整理分析，初步确定粤东地区重要的乡土树种（乔木）有100种，隶属于46科。文章对乡土树种的生态习性、观赏特性、在粤东的分布情况等作了分析。并对如何发挥乡土树种的优势以及乡土树种的开发利用提出建议。     

Assessment of morphological and genetic diversity in <Emphasis Type="Italic">Gmelina arborea</Emphasis> Roxb.

Gmelina arborea is an important timber-yielding tree that grows naturally in the tropical and subtropical regions of Southeast Asia and has also been introduced as a plantation species outside these regions. Genetic diversity in this tree species was observed in stone/seed-related traits and in vitro responses of cultured nodal segments from plants of eight different populations representing natural forests, fragmented forests and plantations. Variance analysis showed significant differences between populations for these traits. However, it was not possible to separate the different populations using these traits by multivariate analysis, even after environmental variation was reduced over six subcultures. Genetic diversity was therefore analysed using molecular markers. Inter-simple sequence repeat (ISSR) primers yielded 95% polymorphic loci among the eight populations and UPGMA analysis enabled separation of these populations on the basis of their genetic distances. Diversity was also analyzed using population genetics parameters like Nei’s genetic diversity and gene differentiation. Nei’s genetic diversity was 0.29 between populations and 0.11 within populations. AMOVA analysis indicated 41 and 59% within- and between-population genetic diversity, respectively. Mantel test suggested that genetic differentiation between six Indian populations was positively correlated to geographic distance (r = 0.626, P = 0.029). Assessment of the genetic variation in G. arborea populations is an important step in selection of conservation strategies for this species since diversity forms the basis for species adaptation.     

在长白山生态系统中长期的高浓度CO2熏蒸对土壤酶的影响

从1999年到2006年在中科院长白山森林生态系统定位站（42°24＇N,128°28＇E,海拔738m）对长期高浓度CO2熏蒸对土壤酶活性的影响进行了研究.采用开顶箱（OTC）的方式对红松和长白松进行高浓度CO2处理, CO2浓度分别受控于高浓度CO2箱（500 μmol·mol^-1）、对照箱（370 μmol·mol^-1））和裸地（370 μmol·mol^-1）.经高浓度CO2（500 μmol·mol^-1）熏蒸8年后,土壤样品分别在2006年春季、夏季和秋季进行采集和分析.结果表明：在高CO2浓度（500 μmol mol^-1）条件下,转化酶活性除了红松夏季样品之外都是显著降低的;而脱氢酶活性却是增加的,但只有部分结果显著;长白松的多酚氧化酶活性都显著降低;过氧化氢酶活性在春季增加,而在其他季节均降低.总而言之,在高CO2浓度条件下,土壤酶的活性与树种有关.     

Changes in carbon stocks and tree diversity in agro-ecosystems in south western Uganda: what role for carbon sequestration payments?

Direct payments offered as compensation for adopting practices which increase carbon sequestration have implications for biodiversity conservation. This study analyzed changes in carbon stocks and tree diversity on carbon and non-carbon farmers’ plots in a pilot carbon offset project implemented by smallholder farmers in south western Uganda. On carbon farms, results indicate a respective decline and an increase in carbon density on farmlands and grasslands. On non-carbon farmers’ plots, there was an increase in both farmland and grassland carbon density. Carbon densities in farmland were significantly (t = −2.38; P = 0.023) higher than those in grasslands. There were no significant differences in tree diversity on farmlands but significant differences (species richness t = 2.18; P = 0.04; Shannon Index t = 2.92; P value = 0.0077) in grasslands. Tree diversity on carbon farmers’ plots decreased in farmlands, but increased in grasslands, while for non-carbon farmers there was a decline in tree diversity in both grasslands and farmlands. There were strong positive correlations between carbon density and tree diversity.     

Soil organic carbon under a linear simultaneous agroforestry system in Uganda

The objective of this study was to quantify and compare the amount and distribution of soil organic carbon (SOC) under a linear simultaneous agroforestry system with different tree species treatments. Field work was conducted at Kifu National Forestry Resources Research Institute in Mukono District, Central Uganda, in a linear agroforestry system established in 1995 with four different tree species and a crop only control treatment. Soil samples were collected in 2006 at three depths; 0–25, 25–50, and 50–100 cm, before planting and after harvesting a maize crop. The results indicate that an agroforestry system has significant potential to increase SOC as compared to the crop only control. There was no significant difference in the amount of SOC under exotic and indigenous tree species. Among the exotic species, Grevillea robusta had higher SOC than Casuarina equisetifolia across the entire depth sampled. There is significant difference in SOC among the indigenous species, where Maesopsis eminii has more SOC than Markhamia lutea. Distance from the tree row did not significantly influence SOC concentration under any of the tree species. In selecting a tree species to integrate with crops that will sequester reasonable quantities of carbon as well as boost the performance of the crops, a farmer can either plant an exotic species or an indigenous. In this study, the soil under Grevillea robusta and Maesopsis eminii have the highest potential to store organic carbon compared to soil under other tree species.     

广东省一级古树资源现状及空间分布研究

基于广东省古树名木普查,对广东省一级古树的数量、区域分布、树龄结构、树种组成、生长环境特征以及生长状况和权属等进行统计分析。结果表明,广东省有一级古树754株,隶属35科63属82种;科属以桑科、无患子科和樟科占优势,树种以榕树、雅榕、荔枝、樟和银杏为主;空间分布以粤北山区多,东西沿海少,乡村多,城区少;权属以集体为主,树龄主要集中在500~799 a范围,对过半的一级古树采取了保护和复壮措施。古树组成与分布除受自然环境约束外,还受农业种植、植物个体、风水林、宗教与宗祠、开发与迁移等文化要素以及乡土风俗、村规民约和经济价值等因素影响。提出完善古树保护管理法规,实施古树资源动态管理,建立一级古树健康监测管理系统,探索古树生态补偿机制等建议。     

Evaluation of fuelwood quality of indigenous and exotic tree species of India's semiarid region

The fuelwood potential of indigenous (Acacia nilotica, Azadirachta indica, Casuarina equisetifolia, Dalbergia sissoo, Prosopis cineraria andZizyphus mauritiana) and exotics (Acacia auriculiformis, A. tortilis, Eucalyptus camaldulensis andE. tereticornis) trees were studied. Calorific value variations for components, such as, stump, main stem, treetop, branches, foliage and bark, were determined. Tree components differed highly significantly (P<0.01) among groups (indigenous and exotics) and within species. The calorific means ranged from 18.7 to 20.8 MJ/kg for indigenous tree species and 17.3 to 19.3 MJ/kg for exotics. Besides calorific values, other fuelwood characteristics, such as, density, ash, biomass/ash ratio, moisture and nitrogen content were also studied. It was observed that indigenous tree species are better suited as fuelwood species as they contain high density wood, low ash content and low N percentage. The fuelwood value index (FVI) was found to be high of indigenous tree species and was maximum forCasuarina equisetifolia (2815). The most promising tree species were in the order ofC. equisetifolia, A. nilotica andZ. mauritiana.     

Effects of long-term elevated CO<Subscript>2</Subscript> on N<Subscript>2</Subscript>-fixing,denitrifying and nitrifying enzyme activities in forest soils under <Emphasis Type="Italic">Pinus sylvestriformis</Emphasis> in Changbai Mountain

A study was conducted to determine the effects of elevated CO₂ on soil N process at Changbai Mountain in Jilin Province, northeastern China (42°24′N, 128°06′E, and 738 m elevation). A randomized complete block design of ambient and elevated CO₂ was established in an open-top chamber facility in the spring of 1999. Changpai Scotch pine (Pinus sylvestris var. sylvestriformis seeds were sowed in May, 1999 and CO₂ fumigation treatments began after seeds germination. In each year, the exposure started at the end of April and stopped at the end of October. Soil samples were collected in June and August 2006 and in June 2007, and soil nitrifying, denitrifying and N₂-fixing enzyme activities were measured. Results show that soil nitrifying enzyme activities (NEA) in the 5–10 cm soil layer were significantly increased at elevated CO₂ by 30.3% in June 2006, by 30.9% in August 2006 and by 11.3% in June 2007. Soil denitrifying enzyme activities (DEA) were significantly decreased by elevated CO₂ treatment in June 2006 (P < 0.012) and August 2006 (P < 0.005) samplings in our study; no significant difference was detected in June 2007, and no significant changes in N₂-fixing enzyme activity were found. This study suggests that elevated CO₂ can alter soil nitrifying enzyme and denitrifying enzyme activities. Foundation project: This research was supported by the National Natural Science Foundation of China (No. 90411020) and Major State Basic Research Development Program of China (973 Program) (2002CB412502).     

广东西樵山国家森林公园景观格局分析及优化

城郊森林公园是提升大众福祉、发挥生态功能的载体。以广东西樵山国家森林公园为研究对象，运用 ArcGIS 软件和Fragstats软件对其景观格局进行分析。结果表明，风景林是公园景观的基质（PLAND =67.84%），道路廊道将其与用材林、建筑和水体3种主要景观类型进行串联；公园各景观类型的破碎化程度不同，斑块形状均较为规则（MSI值为1.41~2.12；MPFD值为1.10~1.24）；公园的景观多样性较低（SHDI=1.31），斑块空间分布不均（SHEI=0.53），斑块形状较为复杂（LSI=22.83），各功能分区的格局特征差异明显。城郊森林公园的经营应严格控制人为干扰影响，提高公园景观多样性，注重斑块类型、功能分区和整体景观格局的优化。     

降香黄檀在广西南亚热带地区的引种

通过对降香黄檀在广西的引种驯化及其种质资源保存情况的调查,结果表明,降香黄檀在北移5°左右引种到广西南亚热带地区是成功的,能耐受冬季0℃左右的极端低温,适应在≥10℃年积温为7 200℃以上的地区正常生长。在岩溶石灰山地引种造林,不但能适应气候干旱的石灰岩造林区,而且能适应生长在pH值较高的棕色石灰土;树木生长发育正常,能开花结果,生长速度与原产地相似,能长成大径级用材,24年生林分平均高16.8 m,年均高生长0.70 m,平均胸径24.1 cm,年均生长1.00 cm。     

Covariation between tree size and shade tolerance modulates mixed-forest productivity

Key message

In tree communities, tree size inequality reduces productivity and interacts with tree shade tolerance to modulate stand productivity, with a higher productivity in stands where shade-intolerant species dominate shade-tolerant species in size.

Context

Positive diversity–productivity relationships have been reported in different plant communities, including tree communities. These effects may be strongly related to both structural diversity and functional diversity, but also to their interactions if there is a non-random distribution of species functional characteristics among canopy layers.

Aims

We explore the relative effects on forest productivity of tree species diversity, tree size inequality, and species shade tolerance diversity, as well as the effect of the distribution of tree shade tolerance in the canopy.

Methods

We used 11,054 mixed-species forest plots from the French Forest Inventory (IGN) distributed throughout France (2006–2011). We analyzed the effects of species richness, shade tolerance diversity, and height inequality on forest plot productivity, represented by basal area annual increment over a period of 5 years, while controlling for first-order structure characteristics (basal area and quadratic mean diameter) and environmental factors (soil water budget and sum of growing degree days). Using the covariance between tree height and shade tolerance in mixed species canopies, we also explored the effect of the distribution of species’ shade tolerance among canopy layers.

Results

The results showed a positive effect of species richness (effect size, 0.02) and a negative effect of height inequality (??0.05) on mixed-forest productivity. We also showed that a negative covariance between shade tolerance and height (e.g., higher proportion of shade-tolerant species in lower height classes) increased productivity (0.01). Shade tolerance diversity did not affect productivity.

Conclusion

In tree communities, as shown previously in monospecific forest stands, tree size inequality reduces productivity. This effect is modulated by the distribution of shade tolerance among canopy layers. Previous studies on species diversity effect have generally overlooked the importance of the size structure and the size hierarchy of functional characteristics. These effects are, however, crucial and deserve to be explored in greater detail.

     

Assessment of natural regeneration status and diversity of tree species in the biodiversity conservation areas of Northeastern Bangladesh

A study was conducted at two-biodiversity conservation areas of Northeastern Bangladesh (a part of Sylhet Forest Division) to assess the species composition, diversity and density of natural regeneration of tree species both indigenous and exotic species. Data were collected by stratified random quadrate method during January 2010 to July 2010. Totally 200 circular plots of 2 m×2 m in size had 5 different habitat types of plants namely; forest, roadside, homestead (surrounding forest dwellers house), fallow land and others (canals, streams and tea gardens side), which included a total of 55 regenerating species belonging to 28 families. Meliaceae is the dominant family and shows the highest family importance value (26.3), having six species, followed by Moraceae (24.24). Among the five habitat types, forest (43 species) possess the highest number of species, followed by roadside (23 species). Total 15 exotic species among 9 families and 40 indigenous species with 24 families were recorded. For exotic species, Tectona grandis possess the highest relative density (11.7%) and relative frequency (10.5%); Senna siamea had highest relative abundance (7.83%). In case of indigenous species, Chickrassia tabularis possess the highest relative density (4.23%) and relative frequency (4%); Dipterocarpus turbinatus had the highest relative abundance (3.92%). Tectona grandis (29.66) and Chickrassia tabularis (10.8) had the highest IVI for exotic and indigenous species respectively. Different diversity indices such as Shanon-Winner diversity index, species diversity index, species richness index, species evenness index, Simpson index and species dominance index, etc. were applied to quantify definite diversity. The regeneration of species associated with low levels of disturbance was in the exotic species. Study suggests that proper protection from human disturbances and scientific management of natural regeneration of two-study forests may lead a rich biodiversity site in the country.     

择伐后长白山北坡天然次生林乔木种多样性的变化动态

通过调查了不同时期择伐后形成的长白山北坡天然次生林的群落特性,研究了28年恢复期间乔木种多样性的变化动态。结果表明:(1)天然次生林内林分的乔木种丰富度S变化较小,始终保持在18-22;(2)在次生林内更新层、演替层及林分的Simpson指数D变化趋势基本类似,主林层在受到干扰后的前15年恢复期Simpson指数D缓慢减小,第15年以后变化比较小;(3)天然次生林的多样性指数变化较小,Shannon-Wiener指数(H)变化幅度始终保持在原始林的H±10%以内。图3表1参14。     

Exotic tree species displace indigenous ones on farms at intermediate altitudes around Mount Kenya

Agroforestry systems are potentially suitable for conservation of tree genetic resources. Farmers around Mt. Kenya usually integrate trees into their farm. Large parts of these trees seem to be of exotic origin, whereas indigenous species have priority for conservation. This study aimed at determining on-farm richness, composition and frequency of indigenous and exotic woody species around Mount Kenya to assess the suitability of farms for the conservation of indigenous tree species. 265 on-farm plots of 0.5 ha size each were selected in 18 different agro-ecological zones by using a stratified sampling scheme. All woody species within the plot were recorded with their local and scientific names. Total species richness was 424 (including 306 indigenous ones), mean richness per plot 16.5 species (including 8.8 indigenous ones). Eight out of the 10 most frequent species were exotic ones with Grevillea robusta from Australia ranking first (found on almost 76% of the surveyed farms). The proportion of indigenous species increased with increasing aridity and temperature. Dominance of exotic species was found at farms of humid mid- and highlands. Ordination analysis revealed that mostly exotic species contributed to separation of farms in the highlands and upper midlands, whereas indigenous species in the lower midlands and lowlands. As the frequencies of most indigenous trees were low, only parts of the surveyed farms can contribute to conservation of tree genetic resources, particularly the less intensively managed farms of the more arid lands. Farmers’ access to knowledge on valuable indigenous tree species and to quality seedlings of these trees need to be improved to increase indigenous species’ frequencies on farms and possibly to replace some of the exotic species in the future.     

Somatic embryo culture for propagation,artificial seed production,and conservation of sawara cypress (<Emphasis Type="Italic">Chamaecyparis pisifera</Emphasis> Sieb. et Zucc.)

 Somatic embryogenesis in Chamaecyparis pisifera Sieb. et Zucc. was initiated from immature seeds collected from the end of June to early July. Mass propagation through adventitious shoot bud production from somatic embryo culture on Woody Plant (WP) medium and artificial seed production using sodium alginate was achieved. A high bud forming index value (25.8) was obtained on medium supplemented with 1 μM 6-benzylaminopurine. The conversion rates from artificial seeds under aseptic and nonaseptic conditions were 60%–100% and 10%–12%, respectively. For germplasm conservation, somatic embryos and embryogenic cells were successfully stored at 4°C (medium-term storage) and in liquid nitrogen for long-term storage. Received: December 21, 2001 / Accepted: August 1, 2002 Acknowledgments This work was supported in part by the Japan Science and Technology Corporation and in part by a Grant for Research for the Future Program from the Japan Society for the Promotion of Science. Correspondence to:E. Maruyama     

Co-occurring tree species show contrasting sensitivity to ENSO-related droughts in planted dipterocarp forests

This study explores the diversity in sensitivity to drought of moist tropical forest tree species. Yearly tree growth records collected over a ten-year period in two one-hectare 70-year-old damar agroforest plots in Sumatra are analysed. These agroforests are mixed tree plantations, dominated by Shorea javanica K. & V., a dipterocarp tree cultivated and tapped for its commercially valuable resin (damar). Many indigenous fruit tree species grow in these agroforests, as well as timber tree species originating from the nearby natural forest. During the census period the multi-species stands were subjected to three El Nino Southern Oscillation (ENSO)-related droughts (1994, 1997 and 2002). At the tree community level, these droughts were associated with a marked decrease in radial stem growth. Multilevel modelling was used to explore the relative contribution of species, tree size and individual tree characteristics to the observed response to drought.All tree species appeared to be sensitive to drought but the amplitude of the response varied significantly across species. Predicted species mean decrease in stem radial growth rate on drought years (i.e. years with 6 months with less than 50 mm/month rainfall) ranged from less than 5% to more than 80%. Shared species were ranked consistently between plots indicating that the results were robust. Stem diameter significantly affected tree sensitivity to drought in two species only, but in opposite ways: in S. javanica, larger trees appeared to be less sensitive while the opposite was true for Lansium domesticum, an abundant fruit tree. Individual tree sensitivity to drought contributed significantly albeit to a small extent to the overall response to drought. This individual tree effect did not show any pattern of spatial correlation and hence could not be related to topographic features. It is likely to reflect the individual's unique history and genotype.     

Habitat selection of Guizhou golden monkey （Phinopithecus roxellanae brelichi）in Fanjing Mountain Biosphere Reserve, China

Guizhou golden monkey (Phinopithecus roxellanae brelichi) is a peculiar, rare and endangered species. It is distributed most narrowly and requires a rigorous habitat. In this study the habitats of Guizhou Golden Monkey were divided into three habitats: most suitable habitats, suitable habitats and marginally suitable habitats. The characteristics of the vegetation community, environmental factors and extreme environmental factors in the three habitats were systematically analyzed. The seasonal activity rule, activity area and the food characteristic of Guizhou golden monkey were also study at the same time. The results indicate that the evergreen and deciduous broadleaf mixed forest is the optimal living vegetation community for Guizhoug olden Monkey, and the suitable annual temperature is 8-15℃, the extremely lowest temperature is -2.5℃, the extremely highest temperature is 25℃, and the optimal living altitude is 1500-1700 m. In the same area, the higher the vegetation diversitythe more suitable it is for the life of Guizhou golden monkey. Temperature and food are the main habitat factors in determining the activity scope of the guizhou golden monkey community. The Altitude, temperature and the characteristics of the vegetation community are the main limitina factors for habitat selection.     

广东省野生树种地理分布新记录

对广东省雷州半岛各地野生木本植物实地踏查与标本采集鉴定,并参照相关文献,发现广东省地理分布新记录树种6个,分别是:硬骨藤(Pycnarrhena poilanei(Gagnep.)Forman)、光叶海桐(Pittosporum glabratum Lindl.)、台琼海桐(Pittospo-rum pentandrum(blanco)Merr.var.hainanense(Gagnep.)Li.)、铁线子(Manilkara hexandra(Roxb.)Dubard)、光叶柿(Dio-spyros diversilimba Merr.et Chun)、玉蕊(Barringtonia racemosa(Linn.)Spreng.)。