Carbon gains and recovery from degradation of forest biomass in European Union during 1990–2005

The net gain of carbon in European Union (EU) forest vegetation during 1990–2005 was estimated at 360–400 Tg CO₂ year⁻¹ by analysing international data. This amount is at low end of the range of recent corresponding estimates, but greater than earlier estimates published for the period 1971–1990. The sequestration took place almost exclusively in areas which were already forested in 1990. In 2005, new plantations, established after 1990, contributed only about 8% to the estimated net gain. The sequestration was estimated to be the greatest in Germany, France, Italy, Finland and Poland regardless of data source and method of estimation. On a per capita basis, the sequestration was estimated to be the greatest in Finland and Latvia. Carbon sequestration in forests is an important component of the long-term carbon balance of the EU. Carbon sequestration in forests is partly driven by a recovery of the ecosystems from human-induced degradation in the 19th century and the first half of the 20th century. Forest management has affected carbon sequestration and merits attention in climate policy presuming that new policies and measures are reconciled with those already in place for the promotion of the diverse goals of land management in Europe.     

Effect of Isolation of Hainan Island from the Mainland on the Genetic Variation of Podocarpus imbricatus

Random amplified polymorphic DNA (RAPD) markers were used to analyze genetic variation of Podocarpus imbricatus in Hainan Island and Mainland of China. Two populations of Dacrydium pierrei were used as comparison materials. Both Podocarpus imbricatus and Dacrydium pierrei showed a low level of genetic diversity. However, Podocarpus imbricatus showed higher genetic diversity and higher population differentiation than Dacrydium pierrei. The geographic range may affect the geneticdiversity of Podocarpus imbricatus and Dacrydium pierrei signific antly. The UPGMA cluster tree showed that populations of Podocarpus imbricatus in Hainan Island and Guangxi Zhuang Autonomous Region were closer than those in Yunnan Province,indicating possible gene flow between Hainan Island and Guangxi Zhuang Autonomous Region. The young geological history of Hainan Island and the three times of unification and separation between Hainan Island and the Mainland may give the two species more possibilities of gene flow.     

Evaluating the impacts of a carbon tax on imported forest products—evidence from Taiwan

Levying a carbon tax is one of the approaches used to reduce greenhouse gas emissions (GHGEs) and has been adopted in a number of countries since the Kyoto Protocol. Applying such an approach in the forest sector may have important policy implications. The main purpose of this paper is to investigate the effects of a carbon tax on imported forest products using Taiwan as an example. Taiwan relies on foreign imported timber and such consumption of harvested wood products (HWPs) lengthens the storage of carbon beyond the life of the tree. This study investigates the impacts of implementing a carbon tax on seven types of HWPs by applying the ARDL approach to imported timber demand functions in Taiwan. The empirical results show that the volumes of imported HWPs as well as carbon dioxide are significantly reduced once a carbon tax is implemented. These empirical outcomes provide some important forest policy implications for countries importing wood products.     

Effect of the seeds provenance and treatment on the germination rate and plants growth of four forest trees species of C?te d'Ivoire

The rapid rate of deforestation in Cote d'Ivoire has led to loss of plant species diversity and also threatens some commercial tree species with extinction.Some reforestation and afforestation has been completed.However,for some species,the numbers of surviving transplants has declined.Hence,it is necessary to develop properly adapted and resilient genotypes that can effectively support the programs of forest restoration.In this context we evaluated the effects of the provenances of seeds and of various treatments on the germination rates and on plant growth of four commercial trees species(Pycnanthus angolensis,Terminalia superba,Mansonia altissima and Pterygota macrocarpa).We analyzed these parameters for seeds of three provenances(Daloa,Akoupe and Daoukro) of four species and for thirty plants aged 6 months per provenance.Time to begin germination and time to reach maximum germination were similar among species,and were not influenced by either treatment or provenance.Untreated seeds and those soaked for 24 and 48 h in water at room temperature yielded the highest germination rates,irrespective of species or provenance.The one exception was P.angolensis, for which no germination was recorded.Within species,some provenances produced higher germination percentages than did others.No clear relationship was computed between the germination rate and the morphometric characteristics of the seeds which varied significantly between provenances.Plant growth and morphological variability also depended greatly on provenance.Genetic factors might be implicated,therefore provenance trials should be undertaken and evaluated.Furthermore,molecular analysis should be undertaken to confirm the implications of genetic factors and allow for genetic selection.     

Trends of tree growth in Swedish forests 1953–1992: An analysis based on sample trees from the national forest inventory

Average tree height and basal area growth for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) in Sweden were studied as functions of species, age, stand density, location and year of inventory in the period 1953–1992, on the basis of sample tree data from the National Forest Inventory. A highly significant annual increase of both height and basal area growth was found, of the magnitude 0.5–0.8%, during the 40 yr period. Possible reasons for the trend are discussed. The altered way of cutting in the early 1950s, from selective cutting to clear felling and thinning from below, has had a large impact. Also, improved regeneration methods, nitrogen fertilization and ditching have increased growth. The increasing atmospheric deposition of nitrogen is another possible factor.     

Effect of land-use on small mammal abundance and diversity in a forest–farmland mosaic landscape in south-eastern Norway

During the last century the boreal forests of south-eastern Norway have been converted into patchworks of agricultural areas, clear-cuts and even-aged conifer monocultures. Even though Scandinavian forest ecosystems are strongly influenced by small mammals’ dynamics, the effects of anthropogenic changes on these communities are still debated. We conducted an extensive capture–mark–recapture study to examine the relative abundance and distribution of 11 species of small mammals during the reproductive season with respect to all available landscape-scale habitat types and fine-scale vegetation characteristics.     

Manipulation of conventional forest management practices to increase forest growth—results from the Skogaby project

Above ground dry mass production and N accumulation on an areal basis in stems, branches and needles as well as in litterfall in a Norway spruce stand in south Sweden treated with unlimited availability of water and nutrients (fertilisation with irrigation) or of water (irrigation) during a 6 year experimental period are presented. Fertilisation was made in liquid form on a weekly basis during the vegetation period with 100 kg N ha⁻¹ year⁻¹ during each year. The fertiliser also included a balanced composition of P, K, Ca, Mg and S as well as of micronutrients. Irrigation was carried out as soon as a 20 mm water storage deficit developed. It is concluded that there is a large potential to improve Norway spruce production through liquid fertilisation with irrigation. Stem and branch production of Norway spruce was almost doubled due to this treatment. Also, stand needle dry mass and litterfall were markedly increased in comparison with the control. Water and N availability were the two most limiting growth factors. During the experimental period, irrigation had a greater effect on growth than N addition. The gross N uptake increased by 450 kg ha⁻¹ as a result of 600 kg ha⁻¹ fertiliser addition. Needle retention was increased for irrigated trees but needle litterfall remained unchanged. Changing the forest management of Norway spruce to intensive cultivatation results in transitional carbon sequestration in both stand and soil compared with an untreated ecosystem. The largest long-term environmental value is, however, achieved if this cultivated renewable biomass is used as a substitute for fossil fuels. Wood utilisation options of intensively cultivated Norway spruce are discussed.     

Managing forest complexity through application of disturbance–recovery knowledge in development of silvicultural systems and ecological rehabilitation in natural forest systems in Africa

How can we accommodate the diversity in tree species and sizes in mixed-species/size/age stands in the sustainable management of natural forests and woodlands in Africa for diverse timber and non-timber forest products and services, and during rehabilitation of degraded forests? The evergreen moist tropical to warm-temperate forests, from the equator to 34°S, generally function through relative shade tolerance. The tropical, strongly seasonal, drier deciduous woodlands generally function through adaptation to fire and/or grazing/browsing. Silvicultural systems, when implemented, are often not aligned with the ecological characteristics of the particular forest systems or the specific targeted species. This paper presents the concept of using the basic disturbance–recovery processes, with recovery development via stand development stages, as the basis for the development of silvicultural systems suitable for maintenance of forest complexity. Grain analysis and stem diameter distributions, analysed from resource inventories, are used to determine the specific shade- or fire-tolerance characteristics of key economical and ecological tree species. The gained knowledge of the ecosystem and species characteristics (including modes of regeneration, i.e. from seed or vegetative regrowth) and processes is used to simulate the ecological disturbance–recovery processes through the development of mixed silvicultural systems, such as a single-tree selection system, a group felling system and a coppice management system in the same forest. Very similar concepts are used to develop rehabilitation strategies to recover the processes towards regrowth stands of diverse species and structure: through stands of introduced plantations and invader tree species; and through early regrowth stages in deciduous woodlands and evergreen forests, after fire, slash-and-burn traditional agriculture, charcoal production or open-cast mining.     

Spatial patterns of forest fires in Catalonia (NE of Spain) along the period 1975–1995: Analysis of vegetation recovery after fire

This paper revises the results of applying a semiautomatic methodology for fire scars mapping from a time series of Landsat MSS images over the forest and shrubby surface of Catalonia (1975–1993). Perimeters of fires which occurred in 1994 and 1995 were added enlarging the whole series to 21 years from TM imagery. Results are a map series of fire history during 21 years as well as a map of the fire recurrence level. Omission errors are 23% for burned areas greater than 2 km² while commission errors are 8% for areas greater than 0.5 km². Detected fire scars were incorporated into a geographic information system in order to characterise the fire regime of the study area. Fire size distribution and the number of spot fires originated from each fire as well as the maximum distance reached from the main fire are analysed. A first approach to monitor post-burn regeneration through normalised difference vegetation index is also shown.     

Effect of Wood Variables on the Properties of Wood Fiber-Polypropylene Composites

The effect of wood species (Chinese fir and Poplar), wood fiber content (10%, 25%, 40%) and wood fiber sizes (16 to 32 mesh, 32-65 mesh, above 65 mesh) on the properties of the wood fiber-Polypropylene composites were studied in this paper. The results indicate that the effect of wood fiber content and size in composite were more important than that of chosen wood species. Compared with polypropylene without wood fiber, the flexural strength of the composites increased when adding wood fiber into polypropylene, but the tensile and unnotched charpy impact strength decreased. And the above strength decreased with the wood fiber content increasing. When the wood fiber size becoming smaller (in higher mesh), the strength increased. In the comparison of wood species, the properties of composite using Chinese fir wood were better than that of Poplar, but not significant. The dynamic mechanical properties of the composites and PP were also tested and analyzed in this paper.     

Effects of climate factors on the height increment of poplar protection forest in the riverbank field

Based on the data of stand investigation and stem analysis, the effects of climate factors on the poplar protection forest increment in the riverbank field of the Dalinghe and Xiaolinghe rivers of Liaoning Province, China were studied by stepwise regression procedure and grey system theories and methods. A regression model reflecting the correlation between the height increment of poplar protection forest and climatic factor was developed. The order of grey relevance for the effect of climatic factors on the height increment of poplar protection forest is: light>water>heat, and it could be interpreted that the poplar increment was mainly influenced by light factor, water factor, and heat factor. This result will provide scientific basis for the intensive cultivation and regenration of the poplar protection forest in riverbank field in similar regions in China. Foundation item: This study was supported by the National Natural Science Foundation of China (No. 30270250), and a key direction project (No. C12MC-SCMS013) Biography: LI Hai-mei (1975-), female, Ph. D, department of Landscpe Architecture. Art. Laiyang Agricultural College, Shandong Qingdao 266109, P. R. China. Responsible editor: Song Funan     

Analysis of the forest fires in the Antalya region of Turkey using the Keetch–Byram drought index

We investigated the correlation of large fires([300 ha) from 1992 to 2013 within the borders of the Antalya Regional Directorate of Forestry using the Keetch–Byram drought index(KBDI). Daily KBDI values were calculated for each year, and values for the period before the year 2000 differed significantly from those after2000. After 2000(large fires occurred in 2004, 2006, 2007,2008, 2010, and 2013), when KBDI values increased, the KBDI, but not the number of fires, was inversely correlated with the natural log of the burned area(NLBA). While there were both high and low KBDI values when the NLBA was small, only high KBDI values were associated with high NLBA values. Particularly for logarithmic values of 4 and higher, KBDI values increased in parallel with increases in NLBA values. On the basis of a Mann–Whitney U test done in addition to a Pearson correlation test, we found that when the burned areas were grouped according to small and large areas, the KBDI could be used to distinguish the two groups. Using a conditional probability analysis, we found that 4th, 5th and 6th class KBDI values may lead to large fires at the 60 % possibility.Similarly, the possibility of large fires greater than the median burned area in any given 6 years was found to be48 %. In addition, while the mean value of KBDI is 390.51 for the period from May to September for these 6 years, it is 359.93 for the other years. Consequently, the area burned also increased as the KBDI classes(Class 0: 0–99, Class 1:100–199, Class 2: 200–299, Class 3: 300–399, Class 4:400–499, Class 5: 500–599, Class 6: 600–699, and Class 7:700–800) increase.     

Effect of chemical modification on the properties of wood/polypropylene composites

对以铝酸酯为偶联剂对木粉进行表面改性处理后制备的木粉/聚丙烯复合材料的力学性能和形态学特征进行了研究。结果表明:铝酸酯偶联剂可以增加木塑复合材料的抗冲击强度,但会对复合材料的抗拉强度和抗弯强度造成负面的影响。对木塑复合材料的动态力学性能和微分扫描热量分析研究表明,以铝酸酯作为偶联剂,对木塑复合材料的储存模量和损失模量有少许增加,同时可降低材料的熔点和熔解热。利用扫描电镜观察木塑复合材料的木材与塑料界面发现,经铝酸酯处理过的木材与聚丙烯复合界面之间具有更好的相容性。这些研究结果表明,在木塑复合材料制造过程中利用廉价的铝酸酯作为木材化学改性剂,对改善复合材料的性质同样起作良好的作用。图6 表2 参16。     

Strategies on natural forest protection of collective forest area in minority nationality community in China─A case of the forest resource management in datu village

IntroductionForestisakindofmulti-function'resourcethatcanbesustaininglyutiIized,butsomeprobIems,suchasinsufficiencyoftimberyieId,soiIerosion,cIimateim-baIanceinpartdistrictetc.,oftenarousedbecauseofincorrectuseandmanagementofnaturalresources.InordertodevelopthefOrestry,IotsoffOrestrypoIi-cieshavebeenissuedandcarriedout.V8rioustypesofforestresourcesmanagementhavebeenaroused,especialIycollectiveforestareasinsouthChina.However,whydiff6rentefficiencies,good,badandworse,eventoresultinthedecrea…     

Effects of selection cutting on the forest structure and species diversity of evergreen broa-leaved forest in northern Fujian, southern China

The short-term effects of selection cutting of different intensities on the forest structure and species diversity of evergreen broad-leaved forest in northern Fujian Province were investigated and analyzed. The results showed that selection cutting of low and medium intensities caused little variation in the forest structure. After cutting, the dominant species retained their leading status in the community. However, the community structure changed significantly following selection cutting of high and extra-high intensities; the status of the dominant species of the community declined dramatically. Some tree species began to disappear from the sampling plots. Except for extra-high intensity cutting, the diversity of tree species did not change significantly for the other three cutting intensities. However, the evenness of the stands was very different among the four kinds of cutting plots. For low and medium intensity selection cutting, the evenness declined slightly. For extra-high intensity selection cutting, the evenness increased to some extent, which might be due to a more even distribution of tree species after cutting. Cutting operations resulted in some adverse reactions to development of arborous species diversity of evergreen broad-leaved forest, particularly serious damage to the forest canopy. But the rational selection cuttings, which may benefit the restoration and maintenance of species diversity over a long period and may come about from the variations in environmental factors such as sunlight, temperature and humidity.     

Effect of organoclay platelets on the mechanical properties of wood–plastic composites formulated with virgin and recycled polypropylene

Abstract

This study investigated the effects of organoclay platelet contents (0, 3 and 5 wt%) and polypropylene type (virgin and recycled) on the mechanical properties of polypropylene/wood flour composites. Composite samples were made by melt compounding and consequent injection moulding. The tensile, flexural and impact properties of resultant composites were determined. X-ray diffraction (XRD) analysis of composites with 3 and 5% nanoclay content was also conducted. The results indicated that tensile and flexural properties of the composites increased with the addition of nanoclay particles up to 3 wt% and decreased thereafter. The impact strength of the composites, however, decreased with the incorporation of nanoclay. The mechanical properties of the recycled polypropylene-based nanocomposites were statistically comparable with those based on virgin polypropylene. XRD analysis revealed that the degree of intercalation in the nanocomposites containing 3% nanoclay was higher than in those containing 5%. Based on these results, it can be concluded that recycled polypropylene could be used instead of virgin polypropylene in the production of value-added products with no significant adverse effects on the mechanical properties.     

Effects of variable retention logging in the boreal forest on the bumble bee-influenced pollination community,evaluated 8–9 years post-logging

Boreal forests are currently facing intensified logging pressures, yet we know little about impacts of logging on the pollination community. This study extends research done immediately before and after logging, to consider its longer term effects. We censused bumble bee and flower communities 8–9 years after experimental variable retention logging. Harvest treatments left 0%, 10–20%, 50–75%, or 100% of the original trees after logging. Total bumble bee and floral abundances were increased by all forms of logging; however the floral community in retention cuts (i.e., 10–20% and 50–75% of trees remaining) was more similar to undisturbed controls than was the community in clearcuts. Bumble bees in low-retention treatments (i.e. 10–20%) were in an ideal free distribution (IFD) with their floral resources, which allows for equal per-flower rate of visitation, regardless of local flower density. In clearcuts (i.e. 0%) and high-retention areas (i.e. 50–75%) bees were at an IFD with respect to the density of their floral resources, but undermatched (in 50–75% treatments) or were resource-independent (in 0% treatments) with respect to the energetic value of their floral resources. Bees in unlogged forest controls (i.e., 100%) deviated from an IFD by undermatching. Overall, low-retention logging (10–20%) was an improvement over clearcutting, because there was less change to the floral community, while still allowing for the achievement of an ideal free distribution. However, unlogged forest appeared to be negatively affected (in the lack of an IFD) by the presence of adjacent logged forests: numerical responses of bees to flowers were altered, with implications for bee foraging success and plant pollination service. Forest reserves should therefore incorporate buffer zones when adjacent to logged forest, to preserve the inter-relationships in their bee-influenced pollination community.     

Reprint of 'Are forest researchers only scientists? Case studies on the roles of researchers in Japanese and Swedish forest policy processes'

The aim of this study is to clarify the roles of researchers in forest policy development processes. Comparative case studies between Japan and Sweden were conducted. The research–integration–utilisation (RIU) model on scientific knowledge transfer was employed as a framework. Based on the RIU model, ‘scientist’, ‘integrator’, and ‘policy entrepreneur’ were defined as three hypothesised roles of researchers, discussed in conjunction with Pielke's ‘honest broker’ model. It was found that researchers played important roles, both as scientists and integrators in Japan. In Sweden, researchers played only the role of scientist. However, no researchers working as policy entrepreneurs were found in either country. These results indicate that the RIU model could work as a basis for the comparison between countries and the clarification of the roles of researchers in forest policy processes. The case study analysis also specified three additional topics for further discussion: (1) different types of science-based policy advice; (2) the relationship between power allies and consensus building; and (3) the reason why the roles of researchers differ between Japan and Sweden.     

Impact of drip fertigation on arecanut–cocoa system in humid tropics of India

A 5-year field trial was conducted on a laterite soil to evaluate the effects of organic and inorganic fertigations in arecanut sole and arecanut–cocoa land use systems at Vittal, India. Arecanut registered similar yield levels in sole and arecanut–cocoa cropping situations (3,022–3,117 kg ha^?1). Fertigation of 75 % NPK, vermicompost extract (VCE) 20 % N and VCE (10 and 20 % N)+25 % NPK registered the same yield levels (3,029–3,375 kg ha^?1). Dry bean yield of cocoa was at par with fertigation of 75 % NPK and 20 % N VCE + 25 % NPK (291–335 kg ha^?1). Fertigation @ 75 % NPK increased the yield of cocoa by 52 % over VCE alone. The productivity per unit area (kg ha^?1) was significant and higher by 12 % in arecanut–cocoa system (3,450) than arecanut sole (3,090). Productivity was similar to fertigation of 75 % NPK, 20 % N VCE and VCE (10 or 20 % N) + 25 % NPK (3,316–3,665 kg ha^?1). Leaf nutrient status of arecanut and cocoa indicated lower levels of N and K and above normal levels of Ca, Mg and micronutrients. The results indicate that drip fertigation increases the productivity, but precision application of N and K is required for sustaining the yields.