Hydrological impacts of afforestation — A review of research in India

We review the current status of experimental studies in India to understand the linkages between afforestation and hydrology. This discipline deals with the use and management of water, social awareness of environmental problems, and ecosystem limitations on provision of watershed services by river basins in the mountain regions of India. Our review begins with examination of experimental works in tropical countries and proceeds to discussion of initiatives of Indian research institutes and Government organizations towards establishing experimental watersheds to understand the impacts of land cover changes on hydrologic regimes in the Indian sub-continent. This is followed by the review of the experimental work carried out by various authors to assess the impact of land cover changes on major water balance components such as, runoff, groundwater, evapotranspiration and sediment yield. The spatial scales of these experiments have been limited to small watersheds or field plots. This paper also describes impacts of human interventions （such as planta- tions of exotic forest species to restore degraded landscapes） on the water balance components in diverse hydro-geo-environmental conditions in the Indian sub-continent. We focus on identifying the research areas which require immediate attention to develop tools to assist planners and policy makers in assessing and managing the water resources in these complex environments. The review is largely based on research results reported during the last 20 to 30 years.     

Evaluation of genetic fidelity among micropropagated plants of Gloriosa superba L. using DNA-based markers — a potential medicinal plant

Malabar glory lily (Gloriosa superba L.) is a medicinally potent plant species used for the production of alkaloid colchicine. With ever increasing demand, there is a pressing need to conserve it through biotechnological approaches. A large number of complete plantlets were obtained by direct regeneration from the non-dormant tuber explants on Murashige and Skoog (MS) medium supplemented with 2.0 mg/l 6-benzylaminopurine (BAP) + 0.5 mg/l α-naphthalene acetic acid (NAA). Large number of plants can be produced in vitro under aseptic conditions, but there is always a danger of producing somaclonal variants by tissue culture technology. Thus, the genetic stability of micropropagated clones was evaluated using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) analysis. During the study a total of 80 (50 RAPD and 30 ISSR) primers were screened, out of which 10 RAPD and 7 ISSR primers produced a total of 98 (49 RAPD and 49 ISSR) clear, distinct and reproducible amplicons. The amplification products of the regenerated plants showed similar banding patterns to that of the mother plant thus demonstrating the homogeneity of the micropropagated plants. This is the first report that evaluates the use of genetic markers to establish genetic fidelity of micropropagated G. superba using RAPD and ISSR, which can be successfully applied for the mass multiplication, germplasm conservation and further genetic transformation assays for colchicine production to meet the ever increasing demand of this medicinally potent plant for industrial and pharmaceutical uses.     

Analysis of rural people’s attitude towards the management of tribal forests in South Africa

The management of forests for multiple purposes coupled with a varying socioeconomic profile of forest users can result in attitudinal differences towards forest management. This study examines the attitudes of rural people in South Africa towards the management of tribal forests. Attitude towards forest management was analysed with respect to five forest management objectives: 1, forest management for rural livelihood resilience to climate change; 2, forest management for reduction and management of forest fire risk; 3, forest management for sustainable forest-based livelihood; 4, forest management for household socioeconomic wellbeing; and 5, forest management for community-based climate change adaptation initiative. A household questionnaire survey was used to elicit information from 155 rural households using the proportionate random sampling procedure. Chi-square test was used to analyse data from the household survey. Factorial analysis was used to analyse variance in attitude towards forest management. The results showed that rural people generally have positive attitudes toward the management of tribal forests. Factor analysis isolated 2 major factors that explained 61% variance in attitude. Based on the findings we conclude that centralising forest management around the four management objectives (1, 3, 4 & 5) are likely to promote inclusive forest-based development in the study communities.     

Increasing rotation periods during a time of decreasing profitability of forestry — a paradox?

The profitability of forestry in Germany decreased during recent decades because of more or less constant prices for forest products, increasing input prices and limited success in rationalisation. However, the volume of growing stock increased significantly during this period since forest enterprises have chosen longer rotation periods. This is especially true for state owned and community owned forests but also at least partly for private forests. It is normally not an alternative for the owners of forest enterprises in Germany to sell the forests completely, but on a first glance increasing investments in standing timber during a time of decreasing profitability of forestry seems to be inconsistent with economic theory. On the one hand this observation could be explained as the result of non-timber values. However, this paper is focused on another approach, which is an expanded Faustmann model in line with soil rent theory and focused on timber production. Profitable rotations in the future have the effect of shortening the optimal rotation period because an investment in standing timber causes opportunity costs by delaying the establishment of the next generation of the forest. Unprofitable future rotations have the opposite effect, if the landowner is forced to reforest. In case investments in reforestations are not profitable decision-makers have good reasons not to cut the mature stands, in spite of the fact that the internal rates of return of investments in standing timber are low in comparison with investments on the financial market. Empirical data for the period 1954–1998 mostly from guidelines for forest valuation are used together with inflation corrected interest rates to show that optimal rotation length increased over time. Nevertheless we have to recognise that the observed rotation periods are distinctly longer than the calculated optimal rotation lengths. Other factors which may also explain the investments in forestry are discussed later.     

A cytotoxic 4α-methyl steroid from the aerial parts of Cimicifuga foetida L

A new 4α-methyl sterol, cimisterol A (1), together with five known compounds (2-6), were isolated from the aerial parts of Cimicifuga foetida L. The new compound's structure was determined with the help of extensive 1D and 2D NMR spectroscopy. Compound 1 exhibited broad-spectrum and potent cytotoxic activities against human HL-60, Jurkat, K562, U937, HepG-2, and SGC-7091 cell lines, with IC(50) values of 7.23, 2.89, 6.88, 3.38, 4.21, and 4.89 μM, respectively. Compound 3 showed moderate to weak activities to all cell lines, except for SGC-7091, having IC(50) values ranging from 13.37 to 17.72 μM. This is the first time a cytotoxic 4α-methyl sterol constituent was discovered from Cimicifuga spp.     

Application of GIS in Biodiversity Appraisal—A Case Study of Solan Forest Division (HP), India

The study was conducted in the Solan Forest Division with an area of 57,158 ha in Himachal Pradesh to study spatial distribution of plant biodiversity. The forest division has an altitudinal gradient from 600–2,260 m amsl. The contours on the Forest Survey of India (FSI) topo sheets (1:25000 scale) for this division were digitized to generate its Digital Elevation Model (DEM). It was stratified into five elevation classes (600–900, 900–1,200, 1,200–1,500, 1,500–1,800, 1800 m and above). A stock map of the division was digitized and superimposed on stratified DEM to know the distribution of vegetation at different elevations. Eight types of land use covers recorded in this division are: (a) chir pine (Pinus roxburghii) forests, (b) bamboo (Dendrocalamus strictus) forests, (c) khair (Acacia catechu) forests, (d) ban oak (Quercus leucotricophora) forests, (e) deodar (Cedrus deodara) forests, (f) broad leaved forests, (g) cultivation, and (h) culturable blank. Around 16.50% of the division's area was estimated to be under different land uses. Total biomass of vegetation in different land uses of the division is estimated as 63.80?×?10⁴ tons. Total carbon stock of the division was 11.71?×?10⁵ tons. Biomass density and carbon density were found to increase with elevation.     

Soil and plant N-budget 1 year after planting of a slash-and-mulch agroforestry system in the eastern Amazon of Brazil

Nutrient losses during slash-and-burn clearing in tropical forests, coupled with demand by food crops, can deplete nutrients and result in crop abandonment after 1–2 years. Slash-and-mulch technology prevents nutrient losses from burning, while mulch decomposition may serve as a nutrient source. This research investigates the release of nutrients from the mulch and potential uptake of released N by plant biomass after a multi-species agroforestry system was planted in June 2005, following the clearing of a 1 ha of 7-year-old forest with a mulching tractor in Igarapé Açu, Brazil. The study evaluated soil conditions, mulch decomposition, and nutrient concentrations of Manihot esculenta and native vegetation under treatments of P+K fertilization in combination with four native tree species and N-fixing Inga edulis, or with three native tree species without I. edulis. Mulch layer N, Ca and Mg content decreased in response to fertilization, while mulch layer P and K content increased. Nutrient content increased in M. esculenta stems and tubers with fertilization and in the presence of I. edulis, and in competing vegetation with fertilization. Estimated tree N content increased 311 % with fertilization, but by 154 % in the presence of I. edulis. Fertilization with P+K, as well as the presence of I. edulis, increased N stocks in total biomass.     

Growth and wood properties of a 38-year-old Populus simonii × P.nigra plantation established with different densities in semi-arid areas of northeastern China

To characterize the effects of plantation densities on the growth characteristics(diameter at breast level,tree height and volume) and the common wood properties,38-year-old Populus simonii 9 P.nigra clones planted with four levels of spacing(2 m × 2 m,3 m × 3 m,4 m × 4 m,and 5 m × 5 m) in a semi-arid area in northeastern China were examined.The results of ANOVA showed significant differences(P0.01) for all the investigated growth traits and wood properties under different plantation densities,except for the chemical composition of wood.The repeatability and phenotypic variations of all the traits varied from 0.34 to 0.99 and from 13.45 to 59.65%,respectively.Except for wood density,which was significantly negatively correlated with the growth traits,a positive correlation was observed between the growth traits and all the other wood mechanical properties.However,most of the correlations between the growth traits and the chemical composition of the wood were not significant.The path analysis for the wood mechanical characteristics and the growth in the prediction of volume were significant and ranged from 0.18 to 0.72 for wood density and diameter at breast height,respectively,while those for the chemical composition of wood ranged from 0.001 to 0.336,which showed a low impact on the volume.The highest stand volume(610 m~3) per hectare was observed with the 2 m × 2 m spacing,which consequently provided a high total price and income,while a high individual volume growth per tree was observed with the 5 m × 5 m spacing.The results suggested that for the poplar trees younger than 40 years in a semi-arid area in China,2 m × 2 m spacing is suitable for obtaining a high volume per hectare,while 5 m × 5 m spacing is best for obtaining a high individual volume per tree.     

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.     

Functional traits explain growth–mortality trade-offs in a mixed broadleaf-conifer forest in northeastern China

The trade-offs between tree growth and mortality are important indicators of the life-history strategies of species and have been demonstrated to be maintained by inherent fitness differences among species. There is a growing consensus that functional traits which inflect the ecological performances of individuals may be correlated with growth–mortality trade-offs within communities. In this study, the aforementioned trade-offs were detected and their relationships with the functional traits were examined, based on data collected in a typical temperate forested area in northeastern China. Principal components analyses were performed for growth–mortality trade-off relationships. The factor scores on the first principal component were used to represent the species’ positions at an axis of life-history variations among different species. Correlation and multiple regression analyses were performed for the purpose of detecting the relationships between functional traits and the growth–mortality trade-off. The results showed that there were significant trade-offs between the tree growth and mortality rates in the examined plot. Among the six functional traits which were considered, the H_max was found to have the strongest effects on the demographic rates and trade-offs. The observed negative effects on the tree growth and mortality rates suggested that the large species often grow more slowly and living longer, while species at small adult size grow fast but die easily. It was also observed that the specific leaf area and the leaf carbon content level were also very important to the growth and mortality trade-offs. The traits considered in this study explained 68% of interspecific variations in the species positions in the growth–mortality trade-off. In addition, wood density was found to show no effect on the trade-off. This was likely due to the fact that the density of the wood may influence the demographic rates more strongly during the early life stages of the trees. The results of discrimination analysis further confirmed the explanations abilities of the functional traits on the variations of life-history strategies among the species. Due to the fact that the relationships between the functional traits and the trade-offs were found to be relatively variable, it will be necessary to further consider other traits which are more closely and mechanistically linked to individual performances in future investigations, such as leaf life span, leaf tissue density, photosynthetic capacity, and dark respiration rates.

     

Connecting an architectural plant model to a forest stand dynamics model—application to Austrian black pine stand visualization

• Context  

Forest stand dynamics models simulate the growth of trees in stands; based on field measurements and system knowledge, they provide a relatively precise representation of forest growth and are well adapted for forest management purposes. Architectural models describe the structure of plants according to ontogenetic development processes; as a support of biomass production and partitioning at organ scale, they simulate individual tree development.     

Root architecture characteristics of plant inlay in live slope grating

In the experimental garden of the Department of Soil Bioengineering and Landscape Construction, University of Applied Life Sciences in Vienna, Austria, coarse root systems of three different brush species were completely excavated and semi-automatically digitized. The species were Lonicera xylosteum, Ligustrum vulgare and Euonymus europaeus. The 3-D root ar-chitectures reveal different growth strategies between species, which are related to ecological characteristics and physical soil proper-ties. The root architecture of Lonicera xylosteum and Ligustrum vulgare, planted in the under layer of the live slope grading, where the soil is very tight and the soil water content and fertility are relatively low, is shallow. However, the root distribution of E. eu-ropaeus, planted in the middle layer, where environmental conditions are better, is deeper. Most of the root biomass of the three spe-cies is concentrated in the 0-30 cm soil layer. A quarter of the root biomass of Ligustrum vulgare is distributed in the upper layer of the plant inlay. E. europaeus has a relatively even distribution in the 30-60 cm and 60-90 cm soil layer.     

Biomass energy in industrialised countries—a view of the future

Biomass fuels currently (1994) supply around 14% of the world's energy, but most of this is in the form of traditional fuelwood, residues and dung, which is often inefficient and can be environmentally detrimental. Biomass can supply heat and electricity, liquid and gaseous fuels. A number of developed countries derive a significant amount of their primary energy from biomass: USA 4%, Finland 18%, Sweden 16% and Austria 13%. Presently biomass energy supplies at least 2 EJ year⁻¹ in Western Europe which is about 4% of primary energy (54 EJ). Estimates show a likely potential in Europe in 2050 of 9.0–13.5 EJ depending on land areas (10% of useable land, 33 Mha), yields (10–15 oven-dry tonnes (ODt) ha⁻¹), and recoverable residues (25% of harvestable). This biomass contribution represents 17–30% of projected total energy requirements up to 2050. The relative contribution of biofuels in the future will depend on markets and incentives, on continuous research and development progress, and on environmental requirements. Land constraints are not considered significant because of the predicted surpluses in land and food, and the near balance in wood and wood products in Europe.There is considerable potential for the modernisation of biomass fuels to produce convenient energy carriers such as electricity, gases and transportation fuels, whilst continuing to provide for traditional uses of biomass; this modernisation of biomass and the industrial investment is already happening in many countries. When produced in an efficient and sustainable manner, biomass energy has numerous environmental and social benefits compared with fossil fuels. These include improved land management, job creation, use of surplus agricultural land in industrialised countries, provision of modern energy carriers to rural communities of developing countries, a reduction of CO₂ levels, waste control, and nutrient recycling. Greater environmental and net energy benefits can be derived from perennial and woody energy cropping than from annual arable crops which are short-term alternative feedstocks for fuels. Agroforestry systems can play an important role in providing multiple benefits to growers and the community, besides energy. In order to ameliorate CO₂ emissions, using biomass as a substitute for fossil fuels (complete replacement, co-firing, etc.) is more beneficial from social and economic perspectives than sequestering the carbon in forests.Case studies are presented for several developed countries and the constraints involved in modernising biomass energy along with the potential for turning them into entrepreneurial opportunities are discussed. It is concluded that the long term impacts of biomass programmes and projects depend mainly on ensuring income generation, environmental sustainability, flexibility and replicability, while taking account of local conditions and providing multiple benefits, which is an important attribute of agroforestry-type systems. Biomass for energy must be environmentally acceptable in order to ensure its widespread adoptions as a modern energy source. Implementation of biomass projects requires governmental policy initiatives that will internalise the external economic, social and environmental costs of conventional fuel sources so that biomass fuels can become competitive on a ‘level playing field’.     

Tropical red gums — a source of 1,8-cineole-rich Eucalyptus oil

Tropical provenances of Eucalyptus camaldulensis Dehnh. and E. tereticornis Smith were studied, in their natural habitat in Australia and in a 3.75-year-old progeny trial in Zimbabwe, for their potential to produce medicinal-grade essential oils. Substantial interand intra-specific variation in the contents of five prominent monoterpenes, 1,8-cineole, -pinene, -pinene, limonene and p-cymene was found. Plantations of E. camaldulensis established in the wet/dry tropics using seed from Petford in northern Queensland offer immediate potential for oil production. Other widely-planted Queensland provenances with oil potential are Gilbert River Bridge E. camaldulensis and, after some genetic improvement, E. tereticonis from Morehead and Kennedy Rivers. Select individual trees at Petford provide oil of enhanced quality, at about double the yield of average trees.