Concentration variations of several ions in stream after a wildfire

In May 2006, a high intensity wildfire occurred in Songling forest region in Daxing＇an Mountains, China. The concentration changes of eight ions （K^＋, Na^＋, Ca^2＋, Mg^2＋, Cl^-, Br^-, NO3^- and SO4^2-） were measured in burned and tmbumed streams after fire from May to Oct., 2006. Results show that the most ions flux were higher in burned stream than that in unburned stream during the sampling period, and the greatest concentrations of most ions transported from burned stream occurred in July. After fire, the most amplitude chemical ion was Ca^2＋, whose average concentration was 5.50 mg·L^-1 higher than that in unburned stream, and the total concentration of every chemical ion presents a trend Ca^2＋〉SO4^2- 〉Na^＋〉Mg^2＋〉NO3^- . The average concentrations of Ca^2＋, SO4^2- , Na^＋＇Mg^2＋,NO3^- showed an increase trend, but those of K^＋, Cl^- , Br had a decreased trend. SO4^2- had the largest loss among these anions, followed by NO3^-. Overall, the increase degree of cation was greater than that of anion after burning.     

Do fungi have a role as soil stabilizers and remediators after forest fire?

The functional roles of fungi in recovery of forest ecosystems after fire remain poorly documented. We observed macrofungi soon after fire at two widely separated sites, one in the Pacific Northwest United States and the other in southeastern mainland Australia. The range of species on-site was compared against macrofungi reported after the volcanic eruption at Mount St. Helens, also in the Pacific Northwest. Each of the three sites shared species, particularly representatives of the genus Anthracobia. Soon after disturbance, we noted extensive mycelial mats and masses of fruit-bodies of this genus, particularly at heavily impacted microsites. The mycelial mats appeared to play an important functional role on-site, possibly aggregating soil particles in otherwise highly erodable landscapes. We hypothesise that fungi such as Anthracobia are pivotal species in early system recovery after disturbance, helping minimize the movement of soil in the absence of plant roots. As plant root systems recover, the importance of these fungi in soil stabilization may diminish. Other functional roles of early postfire fungi might include nutrient acquisition, leading to the reestablishment of vegetation. These potential roles need to be experimentally tested and relevant findings incorporated into programs aimed at restoring forest ecosystems after disturbance.     

Analysis of growth and nutrition of a young Castanea �� coudercii plantation after application of wood-bark ash

The aim of the present study was to evaluate the effects of the application of wood-bark ash (WBA) on the growth and nutritional status of a 5-year-old hybrid chestnut plantation in two consecutive periods of 3 and 4 years, i.e., from age 5 to 8 years and from age 8 to 12 years, respectively. A field experiment, which included 3 treatments and 4 replicate blocks, was established on an acidic, organic matter-rich mineral soil. The treatments were two different doses of ash (10 and 20 t ha^?1) and an unfertilized control. Application of the ash (by spreading on the ground) produced mean increases of 16% in diameter and 11% in height growth of trees during the first 3 years, considering both doses together; the response was also significant for the subsequent period, particularly with the higher dose of ash (increases of 11% in diameter and 15% in height growth). The ash had a marked effect, although clearly short lived, on pH (H₂O) levels (an increase of 0.6 units) and on exchangeable soil K, Ca and Mg. The nutritional status of the plantation was improved, mainly in terms of K, Ca and Mg, and the results of a vector analysis indicated that these elements, particularly K, were limiting forest production. Foliar or soil nutrient concentrations in the mineral soil were no longer affected by the ash at age 12 years. We recommend the application of two doses of 10 Mg ha^?1 throughout the rotation for fertilizing acid mineral soils that are rich in organic matter.     

China''''s Wood Industry after Joining WTO

After reviewing the present status and prospects of wood industry in the world, the author suggests that in response to the new situation of economic globalization and China's entry into the WTO, the Chinese wood industry should further develop IT application, optimize and upgrade industrial structure and raise quality of labor force, blazing a new trail to industrialization featuring high scientific and technological content, good economic return, low resources consumption, little environmental pollution and a full display of advantages in human resources, so as to enhance its international competitiveness to supply customers better products and services at lower cost.     

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.     

Reforestation with loblolly pine can restore the initial soil carbon stock relative to a subtropical natural forest after 30 years

We hypothesized that long-term loblolly pine (Pinus taeda L.) land-use restores SOC stock and lability of a subtropical Cambisol to the original levels of the natural forest (NF). Additionally, we hypothesized that roots are the major contributor to SOC and that soil stores most of the ecosystem total carbon (ETC). We investigated a chronosequence of loblolly pine land-use of 17 (first rotation) and 32 years (second rotation, unthinned or thinned) following clearing of the NF. The original SOC stock to 100 cm of NF (209?±?9.4 Mg C ha^?1) was depleted by 22% after 17 years of pine, possibly because of intense soil disturbance and low quantity and quality of the residue inputted during the pine stand implementation. However, the SOC stock was restored to the original stock of NF after 32 years of pine, with the input of above and belowground biomass at harvest of the first rotation possibly playing a role in this recovery. Thinning did not affect SOC stocks after 1 year. The POM-C reduced after 17 years and was not recovered after 32 years. We could not ascertain in 5-year evaluation whether root or litter was the major contributor to SOC. Soil held 72% of the ETC in NF and 48–59% in pine plantations, confirming that it stores most of the ETC. Overall, long-term loblolly pine land-use seems to restore the original soil carbon stock in this subtropical site, regardless of some lability losses.     

Spatial variation of local stand structure in an Abies forest, 45 years after a large disturbance by the Isewan typhoon

Heterogeneity of forest stand structure often results from repeated small disturbances, but structural variation also arises in a stand that has regenerated after a single large stand-replacing disturbance. We explored the structural variation within a subalpine Abies forest in Japan that regenerated after a large typhoon in 1959. In 2004, four 50 × 50 m plots were established at two sites in the regenerated forest. To characterize local stand structure within each plot, we determined the stem density, stand basal area, mean diameter at breast height (DBH), and coefficient of variation (CV) of DBH in 10 × 10 m subplots. We analyzed the spatial distribution pattern of the trees in each subplot using the L(t) function and categorized the distributions as clumped or non-clumped. The analysis revealed marked variation among subplots in the stand’s structural characteristics. Although the spatial distribution patterns of the trees in all plots were clumped, 11 of 50 subplots at one site and 39 of 50 subplots at the other site were non-clumped. Subplots with a clumped distribution pattern generally had a smaller basal area, smaller mean DBH, and greater CV of DBH than subplots with the same density but a non-clumped pattern. These results illustrated the spatial heterogeneity of forest structure that can arise in Abies forest that has experienced a large disturbance, probably because of the different densities and distribution of saplings surviving the disturbance and the different forest growth dynamics that result.     

Does inorganic nitrogen limit plant growth 3–5 years after fire in a Wyoming,USA, lodgepole pine forest?

Nitrogen (N) is the major nutrient limiting plant growth and production in terrestrial ecosystems around the world. However, nutrient limitation is spatially variable, and different species within the same ecosystem may be limited by different nutrients. N constraints on plant growth have been investigated via fertilization experiments in a variety of ecosystems; however, recently burned coniferous forests are notably under-studied. Given the recent increase in fire activity across western North America, it is important to understand what limits plant growth and carbon sequestration in coniferous forests recovering from wildfire. We evaluated potential inorganic N limitation in four common native plant species, 3–5 years after stand-replacing wildfire in a lodgepole pine forest (Pinus contorta var. latifolia) in Wyoming, USA. Granular reagent grade ammonium nitrate was added around individual plants at a rate equal to the natural background rate of net N mineralization and at 10× this rate. The grass Calamagrostis rubescens exhibited clear evidence of inorganic N limitation: above-ground biomass and shoot:root ratio increased with the high-fertilizer treatment. Nitrogen:phosphorus (N:P) ratio in un-fertilized C. rubescens plants was <14, also consistent with N limitation, but N:P ratio shifted to >16 in the high-fertilizer treatment, suggesting the onset of P limitation. The upland sedge Carex rossii and seedlings of lodgepole pine were not limited by inorganic N: neither species showed any growth response to N fertilization; N:P ratios were only slightly <14; and foliar N concentrations were greater than critical values reported for mature lodgepole pine. The N-fixing forb Lupinus argenteus was not limited by N, for it showed no growth response to fertilization; rather its N:P ratio of 21 indicated P limitation. In this study, to our knowledge the first experimental evaluation of N limitation in subalpine coniferous forests following wildfire, N limitation was seen in only one of four species tested.     

Dynamics of mediterranean pine forests reforested after fires

Forest fires are frequent under a Mediterranean climate and have shaped the landscape of the region but are currently altered by human action and climate change.Fires have historically conditioned the presence of pine forests,depending on severity and forest regeneration.Regeneration of Mediterranean pine forests is not always successful,and a transition to shrublands or stands of resprouting species can occur,even after reforestation.This study analyses vegetation changes in two Mediterranean p...     

Effects of previous N fertilizations on soil‐water pH and N concentrations after clear‐felling and soil scarification at a Pinus sylvestris site

The study describes effects of clear‐felling and soil scarification on the N concentration and pH of soil water in experimental plots previously supplied with different doses of N. The experiment is situated in central Sweden in a former Pinus sylvestris L. stand. Over a 20‐yr period, plots were fertilized three times with ammonium nitrate, resulting in total doses of 360, 720, 1080, 1440 and 1800 kg N ha^‐1. Soil water was sampled at a depth of 40–50 cm using suction lysimeters, and analysed for N and pH. The study covers one growing season before clear‐felling and six and four growing seasons after clear‐felling and soil scarification, respectively. Statistically significant (p < 0.05) elevations in total N and nitrate‐N concentrations were noted in the fourth to the sixth growing seasons after clear‐felling in the plots that had received 1800 kg N ha^‐1, and in the fifth and sixth seasons in the plots that had received 1440 kg N ha^‐1. Ammonium‐N concentrations were not significantly affected. After clear‐felling, total N and nitrate‐N increased with time at a higher rate in the plots that had received 1440 and 1800 kg N ha^‐1 doses compared with the control. In the sixth post‐cutting season, the nitrate‐N concentration was 0.26 mg l^‐1 in the control and between 0.51 and 4.0 mg l^‐1 in the various fertilized plots. Before clear‐felling, a linear relationship between pH and fertilizer dose was absent. After clear‐felling, negative relationships prevailed, but they differed significantly from the pre‐cutting relationship only during the fourth, fifth and sixth post‐cutting seasons. In the sixth post‐cutting season, the pH was 6.0 in the control, and 6.1, 5.7, 5.6, 5.2 and 4.3 in the plots supplied with 360, 720, 1080, 1440 and 1800 kg N ha^‐1 doses, respectively. The absolute difference in pH between the sixth growing season after clear‐felling and period before clear‐felling increased linearly with increasing fertilizer dose (p < 0.05, R ² = 0.79). Before clear‐felling, nitrate‐N was elevated only in the plots that had received 1800 kg N ha^‐1. After clear‐felling, nitrate‐N seemed to increase in all fertilized plots, but the increase began first in the plots receiving the highest fertilizer dose. It was not until the fifth and sixth growing seasons after clear‐felling that nitrate‐N concentrations appeared elevated in all fertilized plots compared with the control. It seems likely that nitrification caused the increases in nitrate‐N because nitrate‐N accounted for most of the variation in pH in the fourth to the sixth growing seasons. Disc trenching was simulated around some of the lysimeters so that 50% of the soil was disturbed. This did not significantly affect the N concentration or pH of the soil water during the first 4 yrs after scarification.     

Growth of graded sweetgum 3 years after root and shoot pruning

Nursery grown 1–0 bareroot sweetgum seedlings were lifted and graded into two diameter classes (12–16 and 4–8 mm) during the dormant season. Large and small grades were top and/or root pruned and then outplanted on two sites in the lower Coastal Plain of the southeastern United States. Seedling shoots were pruned to 50% of tree height, a 5 cm stump, or no pruning. Seedling roots were pruned to a 15 cm length or left unpruned. Site affected survival but not growth. Smaller, top pruned seedlings performed worse on one site, probably due to greater weed competition. Large seedlings increased survival and growth which increased 3 year average plot volumes by 89%. Top pruning stimulated height growth, but reduced diameter growth and decreased third year seedling volumes. Root pruning did not affect seedling growth. Diameter growth may better indicate treatment impact that height, which has been most commonly used in previous studies.     

Characteristics of Environment Factors in Secondary Poplar-Birch Forests after Mutual-Belt Selective Cutting

Introduction.Secondarypoplar-birchforestswidelydistributedinforestregionofNortheasternChina.Itwasthepio-neercommhnitytowardstheclimaxvegetation,andwasformedfromtheoriginalbroad-leafpil1eforestswhichhadbeenexploitedanddestroyed.Theexperimentalplotislocated…     

Long-term spruce forest continuity – a challenge for a sustainable Scandinavian forestry

Macroscopic charcoal and pollen analysis were used to study the disturbance history and development of a boreal Norway spruce (Picea abies (L.) Karst.) forest landscape in southeastern Norway. The sites studied were natural forests and the charcoal records showed no evidence of fire disturbance that could have broken the continuity in the spruce forests that were established ca. 1700 years ago. Consequently, true spruce forest ecosystem continuity was documented on a landscape level. However, fire disturbed the mixed pine-deciduous forest ecosystems that preceded the present spruce forests, suggesting a shift from fire-prone, to fire-free forest ecosystems.It is argued that the studied forest landscape has the potential to be an important natural reference for future forestry, that would be required to mimic natural forest dynamics to be biologically sustainable. A stereotypic promiscuous use of fire in the regeneration phase may cause serious damages in forest ecosystems that have developed without the impact of fire disturbance.     

Can native vegetation recover after slash pine cultivation in the Brazilian Savanna?

There is a widespread view that forest plantations with exotic species are green deserts, unable to sustain biodiversity. Few studies have demonstrated, however, that planted stands of exotic trees have a greater negative effect on the plant diversity of savanna vegetation. We compared the native woody flora under four stands of slash pine of about 45 years old with four stands where the previously existing native Cerrado vegetation was preserved and protected from disturbances for the same period, has changed into dense vegetation - the “cerradão”, at Assis municipality, São Paulo State, Brazil. Aiming at understanding the potential ecological filters driving these communities, we assessed air and soil humidity, light availability and classified the native species on the basis of shade tolerance, dispersal syndrome and biomes in which they occur (Atlantic Forest or Cerrado). We recorded an average of 70 (±13) species under pine stands and 54 (±16) species in cerradão. Of the total of 136 species recorded, 78 occurred in both habitats, eight were exclusive to the “cerradão” (shade tolerant and also occurring in forest ecosystems) and 18 were recorded only under pine stands (82% heliophytic, exclusive to the Cerrado biome). Among the functional attributes and abiotic variables analyzed, only light availability explained the floristic differences found. Since richness was higher under pine, we refuted the hypothesis that exotic species constrain the establishment of the native species richness in the understory. On the other hand, the dark environment under the closed-canopy of the “cerradão” acts as a filter inhibiting the establishment of typical Cerrado species. Since pine stands, if managed in long cycle, maintain a reasonable pool of Cerrado endemic species in the understory pine plantations may be a good starting point for savanna restoration.     

Do me a favour-don''''t touch

Every year the RSPCA hears from many people who find what they think is an abandoned young bird or other orphaned animal.In almost every case the youngster has not been abandoned and‘ 　　What is a fledgling?rescuing’ it will do more harm than good.　　it is a young bird which has grown all or most of its feathers.　　if you find a young bird out of its nest,here are so　　Fledglings may leave the nest before they can fly.Don't try to return a me tips to help you decide what to do.fledglin…     

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.     

Regulation of research: is it a drug trial or a supplement trial?

Investigators and sponsors of dietary supplement research need to know the relevant regulatory requirements and how to comply with them. This brief review describes how research on dietary supplements is regulated by FDA. In general, whether an FDA sanctioned Investigational New Drug (IND) application is required for a human research project on dietary supplement depends on the intended use and clinical setting of the clinical study, and not on the supplement's physical or chemical properties. Even if the study product is already available on the market as a dietary supplement, an IND will be required for products that will be used as a drug to treat, mitigate or prevent a disease or its related conditions in the proposed clinical study. On the other hand, for studies on structure and function endpoints, and not on drug use, no IND will be required. The paper also discusses the principles FDA uses to determine whether an IND is needed for clinical studies of surrogate endpoints that do not lead to approvable drug claims. Useful FDA contact information is also provided.     

Pasture or permanent crops after slash-and-burn cultivation? Land-use choice in three Amazon colonies

Land use was examined in three settlements – Pedro Peixoto in Acre and Theobroma in Rondonia, Brazil, and Pucallpa, in Peru. Research aimed at characterizing the differences in land use after initial slash-and-burn, and presenting hypotheses to assess the feasibility of improved land uses. Settlers in the Amazon practice slash-and-burn agriculture in forest lands to produce annual crops. After cropping, lands are converted to pasture, or planted with perennial crops, or fallowed in anticipation of future annual crop production. Land use after slash-and-burn cultivation in forest lands differed among the colonies examined. Whereas colonists in Pedro Peixoto converted lands to pasture for cattle production, settlers in Theobroma adopted a strategy encompassing both dual-purpose (milk and meat) cattle and perennial crop production. The more heterogeneous settlers in Pucallpa, who included small-scale cattle ranchers and riverine and forest slash-and-burn farmers, gave more importance to perennial crops. Hypotheses are suggested regarding the described land use differences, and implications for the adoption of agroforestry are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.