The significance of dry forest income for livelihood resilience: The case of the pastoralists and agro-pastoralists in the drylands of southeastern Ethiopia

There is a growing interest to take into account dry forests in planning sustainable development in arid and semi-arid sub-Saharan Africa. A mixed quantitative and qualitative research design involving various data collection tools was employed to examine the significance of dry forest income and associated conditioning factors in the context of pastoral and agro-pastoral production systems of southeastern Ethiopia. Income from livestock and dry forests were the first and second most important components of the total household income. Dry forest income accounts 34.8% and 35.2% of the total household income and 38% and 46% of the total household cash income in the Liben and Afdher Administrative Zones of Somali National Regional State, respectively. It was the largest income compared to all other incomes added together for 45% of the respondents. Most notably, for very poor households, dry forest income contributes up to 63% of their total income. Dry forest income levels varied significantly with occupation (P < 0.05), pastoralists generating more income than agro-pastoralists. Dry forest income enables 24% of households to remain above the poverty line, and it reduces income disparity by 13.7%. Moreover, dry forest income has become increasingly important for households' ex-ante risk and ex-post drought coping strategies. The number of youths per household (P < 0.001), access to extension services (P < 0.001), and being member of a cooperative (P < 0.05) significantly affected dry forest income levels in both Zones. Findings of this study could apply to similar dryland eco-regions in the Horn of Africa and contribute to enhance promotion of sustainable management of dry forests for integrated livelihood adaptation, biodiversity conservation and combating desertification. Further research is needed to quantify the contribution dry forests make to livelihoods through livestock production and to develop options that will guide policy making process to generate additional economic incentives for communities and countries to be engaged in sustainable management and use of dry forests.     

NTFP income contribution to household economy and related socio-economic factors: Lessons from Bangladesh

Exploring extent and pattern of non-timber forest product (NTFP) income contribution to livelihoods of forest-adjacent people and the income related socio-economic factors is crucial in designing any development and conservation initiative. This paper examines NTFPs' role in contributing to the household economy and how different socio-economic factors may influence this contribution. Field methods involved quantitative and qualitative data collection of forest-adjacent households of Chittagong Hill Tracts in Bangladesh. Results show that the contribution of different types of NTFPs to household economy varies in terms of subsistence and cash income. However, overall NTFP income is much higher than income from timber or firewood which indicates a larger dependence of the households on NTFPs. Income data analysis also finds that the poor households are relatively more dependent on NTFPs for their subsistence and cash income than the better-off households. Moreover, the study reveals that there are many other socio-economic factors at the household level such as number of members in household and total value of household implements and furniture that are significantly correlated with the NTFP income. More site-specific applied research on NTFP income and influential factors is necessary to generalize the findings for other parts of the world with similar socio-economic and environmental settings.     

A comprehensive analysis of teak plantation investment in Colombia

A financial assessment of forest investments is comprehensive if the analysis includes reliable yield estimates, land expectation value (LEV) and risk calculation. All of these aspects were considered and applied to teak plantations in Colombia, an emergent economy where high forest productivity, low opportunity cost of land, and decreased financial/economic risk have substantially contributed to promote forest investments. The von Bertalanffy non-linear mixed effect model was used to estimate forest yields using data collected from 31 permanent sample plots, measured over a 17 year period. A stochastic version of LEV along with other financial criteria was calculated by using a computer algorithm and Monte Carlo simulation. Finally, probabilities obtained from stochastic financial calculations were used in logistic models to estimate probabilities of success for a forest plantation project, a measure of risk assessment, after changing land prices. Results suggest that the potential forest productivity (i.e., the biological asymptote) ranges from 93 to 372 m³ ha^− 1. The mean annual increment is 27.8 m³ ha^− 1 year^− 1, which is attained 6 years after the forest plantation is established. Profitability analyses for teak plantations in Colombia suggest a LEV of US$7000 ha^− 1. The risk analyses indicate negligible financial risk for forestlands whose prices are lower than US$2000 ha^− 1.     

Understanding the Contribution of Non-timber Forest Products to the Livelihoods of Forest Dwellers in the Northern Zagros in Iran

One of the features of the forest dwellers in the Zagros region of Iran is their dependence on non-timber forest products (NTFPs). These products can play an important role in the livelihood of households located in the forest. The present study aims to determine the most important sources of forest dwellers’ incomes in the northern Zagros in terms of three income groups (lower, middle, and higher), to assess how changes in income are related to types of NTFPs harvested, and to investigate the most significant socio-economic factors determining absolute and relative household revenue from NTFPs. Income in higher- and middle-income groups come predominantly from border trade between Iran and Iraq, comprising 50 and 44 % of relative income, respectively. The main source of income for the lower-income group is remittance and government interest (such as cash subsidies), comprising 31 % of total household annual income. The relative income from NTFPs depends on the income group, varying between 10 and 21 %. Relative income from NTFPs (such as oak acorns, firewood, Gazoo, and Mazooj) for lower-income households is significantly higher than in middle- and higher-income households (p < 0.05). Feed used for grazing livestock in the forest is the most important type of NTFPs in this area, and its benefit in the higher-income group is significantly higher than that for groups with middle and lower income. A similar result is achieved for tree fodder. Relative income from the NTFPs is positively related to number of household members and negatively related to the average education of adult members of the household, the relative income from border trade, and the relative income from agriculture. Our results support our hypothesis that if there is access to other sources of income for forest dwellers, their dependence on forests would be reduced.     

Population structure and nut yield of a Bertholletia excelsa stand in Southwestern Amazonia

Although Brazil nut (B. excelsa) is often touted as one of the most economically successful NTFPs, little is known about the population structure of this species within its natural range in Southwestern Amazonia or ecological factors that affect fruit production. Since these are considered fundamental for sustainable resource management, we examined a natural Brazil nut stand in an extractive reserve in Acre, Brazil, posing the following questions: (1) What is the spatial distribution, species density, and size–class structure of B. excelsa? and (2) What tree-level factors influence Brazil nut production? In a 420 ha census, 568 trees ≥10 cm diameter at breast height (dbh) were counted, resulting in a density of 1.35 trees ha⁻¹. Based on the nearest-neighbor method, an index of aggregation (R) of 0.77 indicated a rejection of the null hypothesis of a strictly random distribution pattern. Yet, this value suggests a much greater tendency toward randomness than either clumping or uniformity. Our data do not show the commonly reported existence of groves, referring to clearly defined clusters of 50 to several hundred trees separated from similar clusters by great distances. Almost 1/4 of the population (23%) was composed of non-reproductive juveniles. Maximum R² improvement analysis applied to four distinct diameter classes provided insight into the dynamics of production-related variables over the species life cycle. While dbh explained 1/3 of production variance (R² = 0.3360) in the smallest diameter class (10 cm ≤ dbh < 50 cm), which included those in the process of reaching reproductive maturity, crown form best explained production variance of very large trees (dbh ≥ 100 cm). Results also demonstrated a significant negative correlation between crown vine load and production of trees ≥ 50 cm dbh (r = −0.13, P = 0.008), suggesting the need for further study on vine cutting as a possible silvicultural treatment for enhancing nut yields.     

A financial analysis of rain forest silviculture in southwestern Sri Lanka

We examine the financial aspects of three silvicultural systems to encourage the sustainability of valuable hardwood species in mixed-dipterocarp forests of southwest Sri Lanka. We compare the net present value (NPV) of the current forest management approach (diameter limit harvests) with shelterwood harvests that promote light hardwood timber species. In this analysis, we also consider the potential of enrichment planting various precious timber (Diospyros quaesita — calamander), and non-timber forest product (NTFP) species (Caryota urens — fishtail palm; Elettaria cardamomum var. major — cardamom; Calamus zeylanicus — rattan) in conjunction with timber harvests. Two real (inflation adjusted) discount rates were used, 4 and 6%, respectively. Results show that when real discount rates are low (4%), and advance regeneration is present, NPV is highest for the one-cut shelterwood (US $9983 ha⁻¹). At a high discount rate (6%), reflecting the current short-term concession system and unstable rights to harvest, and where no advance regeneration was present, the diameter limit system (US $7173 ha⁻¹) was the optimum. On sites with advanced regeneration, the one-cut shelterwood system is clearly preferable. For all but rattan, shelterwood treatments provide higher NPVs for NTFPs than diameter limit cuttings primarily because of the higher light regimes and more growing space made available early in the rotation. The value for tea cultivation (US $26,000 ha⁻¹) far exceeds the value of managing these lands for timber alone, explaining the dramatic expansion in tea plantations on private lands. However, our results suggest that managing these lands for a combination of timber and enrichment plantings of NTFPs (US $23,000 ha⁻¹) can be comparable to tea plantations. By managing for NTFPs and timber, forest managers have new opportunities to solve the old problems of high-grading and land-use conversion.     

Demand for non-timber forest products: Surveys of urban consumers and sellers in Switzerland

In recent years, worldwide socioeconomic, ecological, and cultural changes have led to a paradigm shift in forestry and forest management. Some years ago, most forest enterprises exclusively focused on wood production, whereas today, forest management is expected to be multifunctional and economically as well as socially and ecologically sustainable [Harrison, S., Herbohn, J., Niskanen, A., 2002. Non-industrial, smallholder, small-scale and family forestry: what's in a name? Small-scale Forest Economics. Management and Policy 1 (1), 1–11; Schmithuesen, F., 2004. Forest policy developments in changing societies — political trends and challenges to research. Towards the sustainable use of Europe's forests: Forest ecosystems and landscape research: Joensuu: European Forest Institute, Proc., vol. 49, pp. 87–99]. In this context, non-timber forest products (NTFPs) such as forest honey, mushrooms, or berries could gain importance as an additional source of income for the forestry sector. To assess the market potential of NTFPs in Switzerland, two corresponding surveys were conducted. A consumer survey (N = 897) conducted in six cities in Switzerland investigated the purchase of Swiss NTFPs, consumer preferences, and demand potentials. An additional survey of sellers of NTFPs (N = 105) looked at these aspects from a complementary perspective. The results showed that there is a high esteem and considerable demand potential for such products among urban consumers. Food products were mentioned most frequently. Both consumers and sellers considered quality and environmental friendliness the most important attributes of NTFPs. Structural and organizational innovations and considerable marketing efforts and sales promotion would be required to expand the market for Swiss NTFP, however. Our results indicate that certification of the products' origin, environmental performance, and quality could support such efforts and that recreational and ecological forest services have a synergetic potential for the marketing of NTFPs.     

Carbon sources and sinks in high-elevation spruce–fir forests of the Southeastern US

This paper examines carbon (C) pools, fluxes, and net ecosystem balance for a high-elevation red spruce–Fraser fir forest [Picea rubens Sarg./Abies fraseri (Pursh.) Poir.] in the Great Smoky Mountains National Park (GSMNP), based on measurements in fifty-four 20 m × 20 m permanent plots located between 1525 and 1970 m elevation. Forest floor and mineral soil C was determined from destructive sampling of the O horizon and incremental soil cores (to a depth of 50 cm) in each plot. Overstory C pools and net C sequestration in live trees was estimated from periodic inventories between 1993 and 2003. The CO₂ release from standing and downed wood was based on biomass and C concentration estimates and published decomposition constants by decay class and species. Soil respiration was measured in situ between 2002 and 2004 in a subset of eight plots along an elevation gradient. Litterfall was collected from a total of 16 plots over a 2–5-year period.The forest contained on average 403 Mg C ha⁻¹, almost half of which stored belowground. Live trees, predominantly spruce, represented a large but highly variable C pool (mean: 126 Mg C ha⁻¹, CV = 39%); while dead wood (61 Mg C ha⁻¹), mostly fir, accounted for as much as 15% of total ecosystem C. The 10-year mean C sequestration in living trees was 2700 kg C ha⁻¹ year⁻¹, but increased from 2180 kg C ha⁻¹ year⁻¹ in 1993–1998 to 3110 kg C ha⁻¹ year⁻¹ in 1998–2003, especially at higher elevations. Dead wood also increased during that period, releasing on average 1600 kg C ha⁻¹ year⁻¹. Estimated net soil C efflux ranged between 1000 and 1450 kg C ha⁻¹ year⁻¹, depending on the calculation of total belowground C allocation. Based on current flux estimates, this old-growth system was close to C neutral.     

Mineral nitrogen dynamics following soil compaction and cultivation during hoop pine plantation establishment

The effects of soil compaction and cultivation on soil mineral N dynamics were investigated through an 18-month, in situ N mineralisation experiment during the inter-rotation and early establishment period of a second rotation (2R) hoop pine (Araucaria cunninghamii Aiton ex A. Cunn) plantation in southeast Queensland, Australia. Treatments were 0, 1 and 16 passes of a fully laden forwarder (gross weight, 40.2 Mg) and cultivation by disc plough (zero cultivation and cultivation). Nitrate N was the dominant form of mineral N throughout the 18-month sampling period in both non-cultivated and cultivated soils, varying between 10 and 40 kg ha⁻¹ whilst ammonium N remained <10 kg ha⁻¹. Compaction had no significant effect on N mineralisation or nitrification. However, the remediation of the effects of compaction on soil through the use of the disc plough had significant impacts on N mineralisation, nitrification and N leaching. On a seasonal basis, the mean net N mineralisation increased from around 30 to 53 kg ha⁻¹, nitrification from 28 to 43 kg ha⁻¹ and nitrate N leaching from around 10 to 73 kg ha⁻¹ following cultivation.     

The economic impact of green-up constraints in the southeastern United States

Green-up, or adjacency, requirements are a common constraint in forestry. The American Forest and Paper Association has developed a Sustainable Forestry Initiative that includes a green-up constraint which limits the average clearcut opening to 48 ha for 3 years or until the average height of the regenerated trees is >1.4 m. In addition to constraining the average clearcut size, many forestry companies in the southeastern USA voluntarily limit their maximum clearcut size to between 60 and 90 ha. In this research, a heuristic algorithm was used to develop tactical forest plans that consider both the maximum and average clearcut sizes. Economic effects of the green-up constraints were estimated for situations where intensive management can reduce the length of the green-up time from 3 to 2 years on a 21 600 ha ownership in Georgia (USA). For a 60-ha maximum opening size, this reduction in green-up time from 3 to 2 years resulted in an additional US$ 66 600 in present net worth (PNW) over a 10-year analysis period. This corresponds to a US$ 10 per harvested ha, or a 0.8% increase in PNW. The benefit gained by reducing the length of the green-up period is less with a 90-ha maximum clearcut size, where PNW increases by US$ 45 600, or US$ 6.70 per harvested ha, a 0.5% increase. While the total volume per period was near the volume goal produced by a strategic forest plan, the spatial restrictions and the desire to maximize net present value resulted in lower volume of timber products (sawlogs and chip-and-saw logs) from older forest stands. A sensitivity analysis showed that an increase in price or yield further reduced the economic incentive for the reduction of the length of the green-up constraint. As price or volume decreased below expectations, however, the incentive to use intensive forest management practices to reduce the length of the green-up constraint became more attractive, since the differences between a 2-year and 3-year green-up time requirement may be large enough to pay for more intensive management practices.     

Initial impact of supervised logging and pre-logging climber cutting compared with conventional logging in a dipterocarp rainforest in Sabah,Malaysia

Pre-marked skid trails, directional felling and climber cutting when logging in tropical rainforests may be important ways of reducing damage to the forest, thus creating a healthier stand and improving future yields.This study, carried out in a virgin dipterocarp rainforest in the south of Sabah, Malaysia, compared two types of logging (both with and without pre-cutting climbers): conventional selective logging (CL) and supervised logging (SL). The latter is a selective logging system in which both pre-marked skid trails and directional felling were implemented. The pre-marked skid trails were aligned parallel to each other, spaced 62 m apart. A randomised complete block 2 × 2 factorial design was used in the experiment, consisting of 16 gross treatment plots, each of 5.76 ha with a 1 ha net plot in the centre.Fewer trees tended (0.050 < P ≤ 0.100) to be logged in SL plots than in CL plots (on average 9.4 and 13.0 trees ≥60 cm diameter breast height ha⁻¹). Pre-felling of climbers resulted in four more dipterocarp trees being logged ha⁻¹, compared with no climber cutting: a statistically significant difference (P ≤ 0.050). The basal areas lost of both large trees (≥ 60 cm dbh) and small dipterocarp trees (10–29 cm dbh) tended to differ between the logging systems, with CL leading to greater losses.There were significant differences in the residual stands left by the logging systems, with respect to the number of dipterocarps and their basal area in the diameter class 10–29 cm; ca 30% more stems being found after SL. No significant differences (or tendencies) in these variables were found in the residual stands in other diameter classes, or when trees of all species were considered.     

New cytotoxic triterpenoid saponins from the whole plant of Clematis lasiandra Maxim

Four new oleanane type triterpenoid saponins (1–4) and three known saponins (5–7) were isolated from the whole plant of Clematis lasiandra Maxim. The structures of the four new compounds were elucidated as 3-O-β-d-ribopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 4)]-β-d-xylopyranosyl hederagenin (1), 3-O-β-d-ribopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)-β-d-xylopyranosyl oleanolic acid 28-O-β-d-glucopyranosyl ester (2), 3-O-β-d-ribopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)-β-d-xylopyranosyl hederagenin (3) and 3-O-β-d-ribopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 4)]-α-l-arabinopyranosyl hederagenin (4) on the basis of extensive spectroscopic analysis and chemical evidence. Compounds 1–7 were evaluated for their cytotoxicity against human tumor cell lines HL-60, Hep-G2 and SGC-7901, and all of the evaluated saponins showed significant cytotoxicity to those three tumor cell lines with IC₅₀ in the range from 1.40 to 19.50 μmol/L except for compounds 2 and 6.     

Effects of uneven-aged silviculture on the stand structure,species composition,and economic returns of loblolly pine stands

Uneven-aged silviculture in loblolly pine (Pinus taeda L.) stands has many economic and ecological benefits. Here, the consequences of various uneven-aged management regimes are predicted with the SouthPro simulator. Results indicate that target distributions for pines with residual merchantable basal areas of ≈12.5 m² ha⁻¹, maximum diameters of ca. 40 cm, and q-ratios of 1.2–1.25 for 2.5 cm DBH classes are likely to provide high economic returns on good sites when combined with hardwood control. Increasing this maximum diameter would enhance tree-size diversity, but reduce sawtimber production and profits. Retaining a hardwood component with 1.15–2.3 m² ha⁻¹ of basal area could enhance tree-species diversity, but this too would result in moderate reductions in income. Insisting on maximizing tree-size diversity or tree-species diversity among softwoods, soft hardwood, and hard hardwoods would be quite costly in terms of lost income and production. Results also illustrate how short-term economic incentives can lead to high-grading practices, despite substantial reductions in stand productivity and net returns in the long term.     

Estimation of biomass and net primary productivity of major planted forests in China based on forest inventory data

Reforestation and afforestation have been suggested as an important land use management in mitigating the increase in atmospheric CO₂ concentration under Kyoto Protocol of UN Framework Convention on climate change. Forest inventory data (FID) are important resources for understanding the dynamics of forest biomass, net primary productivity (NPP) and carbon cycling at landscape and regional scales. In this study, more than 300 data sets of biomass, volume, NPP and stand age for five planted forest types in China (Larix, Pinus tabulaeformis, Pinus massoniana, Cunninghamia lanceolata, Pouulus) from literatures were synthesized to develop regression equations between biomass and volume, and between NPP and biomass, and stand age. Based on the fourth FID (1989–1993), biomass and NPP of five planted forest types in China were estimated. The results showed that total biomass and total NPP of the five types of forest plantations were 2.81 Pg (1 Pg = 10¹⁵ g) and 235.65 Mg ha⁻¹ yr⁻¹ (1 Mg = 10⁶ g), respectively. The area-weighted mean biomass density (biomass) and NPP of different forest types varied from 44.43 (P. massoniana) to 146.05 Mg ha⁻¹ (P. tabulaeformis) and from 4.41 (P. massoniana) to 7.33 Mg ha⁻¹ yr⁻¹ (Populus), respectively. The biomass and NPP of the five planted forest types were not distributed evenly across different regions in China. Larix forests have the greatest variations in biomass and NPP, ranging from 2.7 to 135.37 Mg ha⁻¹ and 0.9 to 10.3 Mg ha⁻¹ yr⁻¹, respectively. However, biomass and NPP of Populus forests in different region varied less and they were approximately 50 Mg ha⁻¹ and 7–8 Mg ha⁻¹ yr⁻¹, respectively. The distribution pattern of biomass and NPP of different forest types closely related with stand ages and regions. The study provided not only with an estimation biomass and NPP of major planted forests in China but also with a useful methodology for estimating forest carbon storage at regional and global levels.     

Utilization and traditional strategies of in situ conservation of iroko (Milicia excelsa Welw. C.C. Berg) in Benin

Socio-cultural surveys were carried out on the basis of a questionnaire administered on 346 respondents in order to investigate cultural and ethnobotanic uses of Milicia excelsa in Benin.M. excelsa contributes to cure 45 human diseases. The different parts of the tree used are leaves (30.3%), bark (25.8%), root (23.6%), latex (10.1%), flaking bark (6.7%), wood, calcium concentrated in old trees, and gum (1.1% each). Fruits or seeds are rarely used. Six different forms of utilization were recorded: soaking (46.3%), bark or leaves decoction (32.8%), herb tea (11.9%), powder (6.0%), leaves or bark grounded and rolled up into ball (1.5%), component of offering to fetish (1.5%). Iroko wood is also used in carpentry and joinery for construction purposes; furniture as well as for building boats/canoes.Iroko tree is used as the conservatory of cultural values and incarnates many divinities, which differ significantly from one province to another (χ² = 1830.27; d.f. = 25; P < 0.01%). There is a significant difference between the provinces in respect of the recognition of the species (χ² = 268.71; d.f. = 17; P ≤ 0.01%) and the population awareness about iroko as a sacred tree also varied from one province to another (χ² = 308.66; d.f. = 27; P ≤ 0.01%).Veneration of the tree is the main approach of its conservation by local people. M. excelsa is conserved on farm, in sacred groves, in public places and in cemeteries. The different sacred objects used to symbolize the divinities incarnated by iroko are: pottery (36.36%), iron (11.11%), calabash (4.04%), candle (2.02%), piece of cloth (18.18%), sacrifice (13.13%), piece of money (3.0%), stone (2.05%), glassware (broken bottle, 2.02%), and convent (8.08%). There is a highly significant difference between provinces as far as the sacred objects are concerned (χ² = 183.037; d.f. = 19 and P < 0.001%). The conservation purposes also vary significantly from one region to other (χ² = 894.47; d.f. = 31; P < 0.01%).     

Genotype × environment interactions in selected loblolly and slash pine plantations in the Southeastern United States

Few studies have quantified the combined effects of silvicultural treatments and genetic improvement on unit area production of full-sib family blocks of loblolly (Pinus taeda L.) and slash pine (P. elliottii Engelm. var. elliotttii). Efficient operational deployment of genetic materials requires an understanding of possible site and silvicultural treatment interactions to maximize yield potential. We examined genotype (family) by environmental interactions (G × E) through age 5 years using a factorial experiment consisting of silvicultural treatment intensity (operational versus intensive), planting density (1334 versus 2990 trees ha⁻¹) and families (seven elite full-sib loblolly and six elite full-sib slash pine families). In January of 2000, randomized complete block, split-plot experiments were installed at two locations for each species in southeast Georgia and northeast Florida. Five years after planting, both loblolly and slash pine demonstrated significant interactions among several factors: genotype × location (p < 0.028 and p < 0.016, respectively), genotype × silvicultural treatment intensity (p < 0.055 and p < 0.059), and silvicultural treatment intensity × density (p < 0.002 and p < 0.001) for basal area (BA) and standing stem volume (VOL). Genotype × silvicultural treatment interactions were positive, with the best overall performing families responding the greatest to intensive treatment. There were changes in slash pine family rankings between locations, which were partly explained by reductions in growth associated with a combination of fusiform rust infection [Cronartium quercum (Berk.) Miyabe ex Shirai f. sp. fusiforme] and wind damage from the 2004 hurricane season. No three-way interactions, which included family, were evident and all genetic sources were stable across the contrasting planting densities. At age 5, loblolly pine outperformed slash pine (p < 0.0001), especially under the intensive silvicultural intensity. While loblolly performance was similar whether deployed in mixtures or pure family blocks, slash pine tended to be more productive in intimate mixtures than when grown in pure family blocks (p = 0.0754 for aboveground biomass).     

Dynamics of above- and below-ground biomass and nutrient accumulation in an age sequence of Nothofagus antarctica forest of Southern Patagonia

Nothofagus antarctica (Forster f.) Oersted is a deciduous tree species, which naturally grows on poorly drained or drier eastern sites in the Andes Mountain near Patagonian steppe. Above- and below-ground biomass and nutrients pools were measured in pure even-aged stands at different ages (5–220 years) and crown classes. Functions were fitted for total biomass and nutrients accumulation, and root/shoot ratio of individual trees against age. Total biomass accumulated for mature dominant trees was eight times greater than mature suppressed trees. Biomass root/shoot ratio decreased with age from 1.8 to a steady-state of 0.5. All nutrients concentration (except Ca) decreased with age and varied according to the degree of crown suppression classes. Nutrient concentrations varied between biomass pool components following the order leaves > bark > small branches > fine roots > medium roots > rooten wood > coarse roots > sapwood > heartwood. Total nutrient accumulation followed the order dominant > codominant > intermediate > suppressed trees and its accumulation rate varied over time, e.g. P accumulation rate of dominant trees increased from 0.17 g tree⁻¹ year⁻¹ during regeneration to 1.39 g tree⁻¹ year⁻¹ in mature trees. Nutrients uptake reached a peak during the period of maximum biomass production, and root/shoot ratio of nutrients decreased from its maximum value at 5 years of age (0.6, 4.0, 0.9, 1.5, 1.0 and 2.6 for N, P, K, Ca, S and Mg, respectively) to a steady-state asymptote beyond 50 years of age. Thus, accumulation of nutrients in roots was greater during the regeneration phase of stand development, and nutrient accumulation increased in above-ground over time. Also, nutrient use efficiency increased in mature trees (111–220 years) and decreased in suppressed crown classes. The equations developed for individual trees have been used to estimate stand biomass and nutrient accumulation from forest inventories data. Total stand biomass varied from 62.5 to 133.4 t ha⁻¹ and total nutrients accumulation ranged from 3 kg Mg ha⁻¹ to 1235 kg Ca ha⁻¹. Proposed equations can be used for practical purposes such as to estimate pasture nutrients requirement in a silvopastoral system based on nutrients supply from leaf litter returns, or to determine amelioration practices like debarking stems before harvesting.     

Pharmacokinetic and metabolism studies of rohitukine in rats by high performance liquid-chromatography with tandem mass spectrometry

A sensitive, selective, and rapid high performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed for the quantification of rohitukine in rat plasma. HPLC was performed using a Symmetry-Shield C₁₈ (5 μ, 4.6 × 150 mm) column, and isocratic elution with ammonium acetate buffer (pH 4; 10 mM):methanol (08:92, v/v) at a flow rate of 0.6 mL/min. Sample clean-up involved solid phase extraction (SPE) of analyte and internal standard (phenacetin) from 100 μL plasma. The parent → product ion transitions (MRM) for analyte and IS were 306.1 → 245.1 m/z and 180.1 → 138.1 m/z respectively, and were monitored on a triple quadrupole mass spectrometer, operating in positive ion mode. The method was validated across the dynamic concentration range of 5–500 ng/mL for rohitukine, with a fast run time of 4.5 min. The analytical method measured concentrations of rohitukine with accuracy (% bias) of <± 10% and precision (% RSD) of <± 12%. Rohitukine was stable during the battery of stability studies viz., bench-top, auto-sampler, freeze/thaw cycles and 30 days of storage in a freezer at − 70 ± 10 °C. Finally, the applicability of this assay has been successfully demonstrated in vivo pharmacokinetic and in vitro metabolism studies in Sprague–Dawley rat. This method will therefore be highly useful for future preclinical and clinical pharmacokinetic studies of rohitukine.     

Distribution,colonization and diversity of arbuscular mycorrhizal fungi associated with central Himalayan rhododendrons

The objective of the present study was to investigate arbuscular mycorrhizal status of five species of rhododendrons distributed in Kumaun region of the Indian Central Himalaya. Root and rhizosphere soil samples of all the five species of rhododendrons, namely, Rhododendron anthopogon, R. arboreum, R. campanulatum, R. barbatum and R. lepidotum were collected from temperate, sub-alpine to alpine location in altitudinal range from 1500 to 4500 m amsl. The arbuscular mycorrhizal colonization in root samples ranged from 28 to 42%; and maximum and minimum colonization was observed in R. arboreum and R. lepidotum, respectively. The highest number of intraradical vesicles (12.5 ± 2.8 cm⁻¹ root segment) was recorded in R. arboreum and the lowest (7.0 ± 1.7 cm⁻¹ root segment) in R. barbatum; vesicles were not observed in R. lepidotum. Spores were extracted from the rhizosphere soil by wet sieving to perform microscopic identification of the species. The maximum and minimum populations of spores were detected in the rhizosphere soil samples of R. anthopogon (52.0 ± 1.5 spores 25 g⁻¹ soil) and R. lepidotum (32.0 ± 2.5 spore 25 g⁻¹ soil), respectively. Spore populations were found to belong to five genera—Acaulospora, Glomus, Gigaspora, Sclerocystis and Scutellispora; genus Glomus was found to be dominant in the rhizosphere soil samples of all the rhododendron species. The most frequent and abundant species was G. fasciculatum, however, this species was not isolated from the rhizosphere soil of R. barbatum. Finger millet (Eleucine coracana) was used to cultivate the trap culture of arbuscular mycorrhizal fungi to confirm the species identity. Spores of Glomus pustulatum, not detected in the rhizosphere soil, were recovered from the trap culture. Contrary to this, genus Gigaspora, which was present in the rhizosphere soil, did not sporulate in the trap culture. Shannon and Wiener index of diversity and Simpson's index of dominance indicated that the species richness, dominance and diversity of arbuscular mycorrhizal fungi decrease with increasing altitude. In two species of rhododendrons, namely R. campanulatum and R. anthopogon, dark septate mycelium was also observed.     

Propensity of farmers to conserve forest within REDD + projects in areas affected by armed-conflict

The implementation of carbon-storage efforts in countries experiencing armed conflicts or confronting illegal activities (such as illicit crop cultivation) will permit additional tropical forests to be protected for climate change mitigation. Yet, despite these potential gains, the appropriate design and application of forest conservation and climate change mitigation approaches such as the mechanism for Reducing Emissions from Deforestation and Forest Degradation (REDD +) in such contexts remain little studied. Unanswered questions relate to the propensity of farmers in conflict affected areas to conserve forests for climate change mitigation. Such questions include, for what reasons and under what circumstances would such farmer participate in climate change mitigation activities? In this paper we address these questions by developing an econometric Logit model to understand factors influencing the propensity to conserve forest of farmers from 14 villages in Colombia. These villages are located in a region recognized as a stronghold of guerrilla insurgencies and as the center for illegal crop cultivation. The region was selected as it is also the proposed target area for piloting Colombian government REDD + activities. A household survey (n = 90) showed that four explanatory variables are significantly related to the ‘propensity to conserve forest’. ‘Harvest of non-timber forest products’ (specifically bush meat) positively influences a farmer's propensity to conserve forest. In contrast, higher ‘percentage of forest area’, ‘deforestation for (the production of) subsistence crops’ and ‘harvest of wood product’, each have a negative influence. Overall, results show an already high propensity to conserve forest among farmers (70% of respondents) and indicate their growing propensity toward the conservation of primary forest and management of degraded lands and secondary forest. These results might be attributable to efforts undertaken to reduce the causes of armed-conflicts and ecosystem deterioration, such as enhancement of land tenure security and farmer associations' rules to reduce deforestation. They might also be linked to communities' positive attitudes toward water resources conservation. We conclude that most farmers will not oppose forest conservation as long as it is compatible with their respective livelihood priorities.