Temporal change in carbon stocks of cocoa–gliricidia agroforests in Central Sulawesi,Indonesia

In a false-time series, the temporal development of cocoa–gliricidia carbon (C) stocks and soil organic carbon (SOC) were investigated in Napu and Palolo Valleys of Central Sulawesi, Indonesia. As a first step, the Functional Branch Analysis (FBA) method was used to develop allometric equations for the above- and below-ground growth of cocoa and gliricidia. FBA resulted in shoot–root ratios of 2.54 and 2.05 for cocoa and gliricidia, respectively. In Napu and Palolo, the trunk diameter and carbon levels per gliricidia tree were always much greater than that of cocoa. The highest aerial carbon levels were attained at year four in Napu (aerial cocoa–gliricidia = 20,745.2 kg C ha⁻¹) and at year five in Palolo (aerial cocoa–gliricidia = 38,857.0 kg C ha⁻¹). After years four or five, however, the reduced stocking density of gliricidia attributed to a loss of aerial C. During the time spans in question, SOC remained fairly stable though slightly decreasing in Napu and slightly increasing in Palolo. The SOC harbored a vastly greater amount of system C (one-half and one-third of SOC in the 0–15 cm stratum in Napu and Palolo, respectively) relative to tree components. Eight years (Napu) or 15 years (Palolo) after conversion of a rainforest to cocoa–gliricidia agroforestry caused an 88% and 87% reduction of aerial C-stocks in Napu and Palolo, respectively.     

The Impact of Cane Supply on Rattan Trade in China

Rattan-related products from China are popular and well known in international market, but China is facing shortage of rattan cane supply, and extinction of some rattan species. The big gap between demand and supply of rattan canes in China market is urgent to be bridged. This paper makes a brief introduction on rattan in the world and analyzes the rattan trade in China. The loss of habitats, overexploitation and inadequate replenishment of rattan result in a depleting resource and there are many challenges and technical issues needed to be dealt with. The forest policies should not only state broad desires but also commit governments to undertake adequate and appropriate measures to protect and develop the resource on a sustainable basis.     

Impact of Drying Methods on Wettability of Populus tomentosa

Plantation poplar is one of the most important resources for wood industry, its utilization field is vast. The wettability of Populus tomentosa with different drying methods was judged by measurement of contact angle using distilled water in this paper. The results showed that the specimens from conventional drying have the biggest contact angle, and the air dried have the smallest contact angle, air dried lumbers have a better wettability than the kiln dried. The changes of contact angle in a period of tim...     

Trophic consequences of postfire logging in a wolf–ungulate system

Controversy surrounds postfire logging, often because of negative effects on snag-dependent wildlife species. Few studies, however, have examined effects on early-seral species that may benefit from postfire logging, nor effects on trophic relationships. We studied the effects of postfire logging on trophic dynamics between wolves (Canis lupus), three ungulate species and ungulate forage biomass during the first 3 years in a large burn in the Canadian Rockies, Alberta, Canada. We examined plant biomass and ungulate responses to two treatments (post- and prefire logging) compared to a burned but unlogged area (control). We evaluated resource selection for the three treatments by elk (Cervus elaphus) using radiotelemetry and for deer (Odocoileus spp.), moose (Alces alces), and, secondarily, elk using pellet counts. Elk resource selection was modeled as a function of the trade-off between wolf predation risk and herbaceous forage biomass to test for trophic impacts of postfire treatments. Postfire logging had transient effects on total herbaceous biomass; while forb biomass was reduced, increases in graminoid biomass more than compensated by the third year. Prefire logging areas were dominated by a few species, but had generally higher forage biomass by the third year. Ungulates avoided postfire and prefire logged areas despite greater herbaceous biomass. Only when we considered elk resource selection as a function of both forage and wolf predation risk was the extent to which trophic interactions affected by postfire logging revealed. Wolves selected proximity to roads and the higher forage biomass associated with postfire logging in open logged areas. This translated to the highest predation risk for elk in postfire logged areas. Thus, ungulates avoided postfire logged areas because of human alteration of top-down predation risk despite enhancements to bottom-up forage biomass. Managers should consider trophic consequences of postfire logging on the interactions among species when gauging logging effects on terrestrial ecosystems. Making use of existing roads, minimizing the construction of new roads, and managing road removal following postfire logging will help mitigate the negative effects of postfire logging on terrestrial ecosystems.     

Impact of Land Tenure Change on Land Use

China is a public ownership country. At present, theownership of land belongs to the country andcollectivity. In China, the meaning of ownership ofland is the light that the owners of land can possessthe land, use the land, get some interest from the landand deal with the land according to laws. The 4 sectionsof ownership of land can either be combined or beseparated to carry out. In practice, these 4 sections ofownership are usually separated to carry out. The tenureof land is an independent…     

Impact of time lags on diurnal estimates of canopy transpiration and canopy conductance from sap-flow measurements of Populus cathayana in the Qinghai–Tibetan Plateau

Recently, canopy transpiration(Ec) has been often estimated by xylem sap-flow measurements. However, there is a significant time lag between sap flow measured at the base of the stem and canopy transpiration due to the capacitive exchange between the transpiration stream and stem water storage. Significant errors will be introduced in canopy conductance(gc) and canopy transpiration estimation if the time lag is neglected. In this study, a cross-correlation analysis was used to quantify the time lag, and the sap flowbased transpiration was measured to parameterize Jarvistype models of gcand thus to simulate Ecof Populus cathayana using the Penman–Monteith equation. The results indicate that solar radiation(Rs) and vapor pressure deficit(VPD) are not fully coincident with sap flow and have an obvious lag effect; the sap flow lags behind Rsand precedes VPD, and there is a 1-h time shift between Ecand sap flow in the 30-min interval data set. A parameterized Jarvis-type gc model is suitable to predict P. cathayana transpiration and explains more than 80% of the variation observed in gc, and the relative error was less than 25%, which shows a preferable simulation effect. The root mean square error(RMSEs)between the predicted and measured Ecwere 1.91 9 10-3(with the time lag) and 3.12 9 10-3cm h-1(without the time lag). More importantly, Ecsimulation precision that incorporates time lag is improved by 6% compared to the results without the time lag, with the mean relative error(MRE) of only 8.32% and the mean absolute error(MAE) of1.48 9 10-3cm h-1.     

The potential of alley farming in humid West Africa — a re-evaluation

Previously published hypothesis concerning the potential impact of alley farming on maize yields are re-examined relative to the humid regions of West Africa. When more realistic assumptions regarding the availability of organic nitrogen are used, it is concluded that alley farming may have potential in a wider range of maize yield environments in West Africa than previously proposed. A pragmatic approach to alley farming research is proposed, and the importance of on-farm research in the development of farmer friendly alley farming is stressed.(Former Agronomist, International Livestock Centre for Africa, P.M.B. 5320, Ibadan, Nigeria)     

Impact of Demographic Structure on Paddy and Forestland Management

INTRODUCTIONChina resorts to socialist public ownership of land.In present, the ownership of land belongs to the stateand collectives. The ownership of land in China refersto the right that the owners of land can possess theland, use the land, get some interest from the landand dispose of the land according to laws. The 4sections of ownership of land can be combined as awhole, and also can be separated to carry out. Beforethe Third Plenary Session of the 11th CPC(Communist Party of Ch…     

Impact of invasion of pine wood nematode on the growth of dominant shrub Pleioblastus amarus in Pinus massoniana communities

When pine trees are invaded by pine wilt diseases,the severely infected pine trees will die and fall down,or they will be removed when found to be damaged by the disease.It gives rise to the invasion of other species in these empty niches originally occupied by pine trees,i.e.,competing surrounding trees or understory shrubs will invade the empty niches during the following years.As a result,the spatial distribution and pattern of the main tree species in a pine forest will change,and a niche variety in the...     

Litter removal impacts on soil biodiversity and eucalypt plantation development in the seasonal tropics

The little layer of tree plantations provides primary nutrients for uptake,buffers changes in soil moisture,and provides habitat and substrate to soil epigeic fauna.However,this layer in eucalypt plantations is often removed to reduce fuel load during the fire season in the Brazilian savanna(Cerrado).Therefore,it is necessary to quantify the effects of changes in litter dynamics on the function of these plantations,on key nutrient cycling processes and on epigeic fauna diversity and abundance.In...     

Dependence of dispersion on vegetation density in a tidal creek‐mangrove swamp system

The dependence of dispersion in a tidal creek on the vegetation density in a fringing mangrove swamp is discussed through a numerical model. A secondary circulation prevails everywhere in the tidal creekmangrove swamp system and is generated by the overflow into the swamp at every high tide. As a result, dissolved and suspended matter moving with the circulation is trapped in the swamp for a fraction of the tidal cycle; it flows out of the swamp at ebb tide and disperses in the creek. The relation between the dispersion coefficient and the mangrove vegetation density is shown to be nonlinear. Dispersion is large both for bare and high vegetation densities and minimum for intermediate vegetation density. The ecological and management applications may be profound as our study suggests that such systems may be unstable and cannot naturally recover from excessive anthropogenic disturbances.     

Impact of land use on woody aboveground biomass in Miombo woodlands of western Zambia – comparison of three allometric equations

Globally, the intensification of land use for agriculture, timber and fuel is considered the leading threat to the diversity and biomass of forests and woodlands. To suggest management options, it is important to understand the patterns and drivers of diversity, structure, biomass and carbon stock of woodland vegetation. In this study we used data from three sites in the Miombo woodlands of western Zambia, which are subject to low, medium and high land-use intensity. We sampled 20 plots of 1 000 m² at each of these sites. Woody vegetation was sampled for richness and structure to provide an understanding of the impact of land-use intensity. Woody plant species richness was not affected by land-use intensity. However, an ANOVA revealed that stem diameter at breast height (DBH) was higher at the low land-use intensity (national park) than at medium and high land-use intensities (selective timber harvest, and non-selective harvest for crop fields and timber). We tested three different allometric equations (one global and two regionally adapted) to determine woody aboveground biomass (AGB) and carbon stock at the three sites. The estimated AGB using the regionally adapted allometric equation of Ryan et al. and the global tropical equation of Brown et al. revealed that the AGB for low and high land-use intensity sites were significantly different from each other with the medium land-use intensity site being intermediate. We concluded that DBH and AGB estimations were influenced by the land-use intensity in the Miombo woodlands as suggested by other studies in the tropical forest and woodlands.     

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.     

Developing phase of China＇s system of nature reserves in perspectiveDeveloping phase of China＇s system of nature reserves in perspectiveDeveloping phase of China＇s system of nature reserves in perspective

Up until 2009, 2541 nature reserves had been established in China. However, the process of developing this system of nature reserves was not quite smooth. Various kinds of information related to nature reserves, such as annual growth, the type of nature reserves established, motives behind building a nature reserve, legal instructions and the constitution of government sectors, were collected and analyzed in order to highlight the characteristics of the devel- apment of our nature reserve system. As a result, we identify three phases and their characteristics, i.e., the initial phase from 1956 to 1978, the establishment phase from 1979 to 1996 and the management standardization phase from 1997 to 2009, could be clearly identified. It is suggested that since the establishment of this comprehensive structural frame- work in China, the system should be entering a new developing phase. We recommend that more attentions should be paid on how to guarantee effective management and how nature reserves are able to maintain their value and fulfill their abjectives in the future.     

Agricultural residues in panel production – Impact of silica particle content and morphology on tool wear

Abstract

Considering ongoing global deforestation and the increased demand for raw materials in all wood-processing sectors it is necessary to seek and employ alternative resources. Agricultural residues are potential sources of alternative lignocellulose-based raw materials. Research on substitute materials for wood panel production mainly focused on physical and mechanical properties of boards while much remains to be learned about machining. Therefore, studies were carried out to analyse the relationship between ash and silica content and their impact on tool wear. Ash and silica contents of agricultural residues were determined following ISO 3340. Particle morphology and elemental composition of selected materials were analysed using scanning electron microscopy and energy-dispersive X-ray analysis. Tool wear tests were carried out using particleboards made from wheat straw, canola straw and spruce. Analyses of various plant materials displayed no correlation between ash and silica content. Bio-mineralised silica structures in wheat and canola were different compared to coarse silica found in wood-based particleboard. Tool wear caused by these agricultural residues was just moderately increased compared to wood, despite the fact that their silica contents were many times higher. Furthermore, the impact of abrasive substances on wear behaviour was influenced by the density of the panels.     

Solubility of wood-cellulose in LiCl/DMAC solvent system

A LiCl/DMAC solvent system was used to dissolve wood-cellulose with aims to broaden its application in preparing func-tional materials of modified wood-cellulose. We studied the dissolubility complexion of wood-cellulose in a LiCl/DMAC solvent system, made sure of the important function of LiCl in a cellulose solvent, and further confirmed its dissolution mechanism via the measurement of infrared spectra of soluble products. The study results are as follows: first, LiCl salts, which can form intermediate complexes with cellulose, have played an important role in the LiCl/DMAC solvent system, and their solubility performance is en-hanced by reducing the hydrogen bond effect between cellulose molecules; second, the non-aqueous solvent system is a better method for dissolving wood-cellulose in homogenous phase. As found in infrared spectra, the absorption intensity of hydroxyl groups (broad peaks: 3,400 cm-1) decreased greatly in cellulose macromolecules. This is because the degree of association between the hy-droxyl groups of cellulose macromolecules is reduced, due to the destruction of the hydrogen bonds. Lastly, wood-cellulose can be dissolved in a LiCl/DMAC solvent thoroughly and efficiently, and can provide a better solvent system for homogeneous synthesis in the preparation of new functional materials via modified wood-cellulose.