Treefall gaps of certified,conventionally managed and natural forests as regeneration sites for Neotropical timber trees in northern Honduras

Forest certification programmes promote sustainable management of the world's forests. Certification can be given to a forest management system that fulfils certain environmental, social and economic criteria.     

Water status and drought stress in experimental gaps in managed and semi-natural silver fir--beech forests

The effect of gap characteristics, including gap age, vegetation cover, and stage of regeneration, on water balance and drought stress was studied over a four-year period in natural and experimental gaps of various sizes in Dinaric silver fir--beech forest in Slovenia. A medium gap, two experimental clear-cut gaps, and a closed stand were selected in a traditional irregular shelterwood managed forest, and an irregular-shaped natural gap and part of the stand were selected in a semi-natural forest. Soil moisture, throughfall, and stemflow were measured in the gaps and stands, and incident precipitation was monitored in the open area. Evapotranspiration and drainage water fluxes were estimated using the water balance model BROOK90. To estimate drought stress, the ratio between simulated actual and potential evapotranspiration was used. Precipitation in the 2001 and 2003 growing seasons was considerably less than that in 2002 and 2004. The highest drainage fluxes were in the newly created clear-cut gaps with sparse ground vegetation cover, followed by the natural gap and medium gap, which had older and denser natural tree regeneration. On average, the clear-cut gap drainage fluxes were 18% (164?mm) higher than those in the forest stands. Evapotranspiration was lower in the natural gap and higher in the managed gap compared with the experimental clear-cut gaps. Water supply stress was greater for the forest stands than for the vegetation in the gaps. Drought stress was indicated to be lowest in the natural gap, which had patches of varying development phases and the highest water storage capacity of the soil and vegetation.     

Structure and floristic composition of old-growth wet evergreen forests of Nelliampathy Hills, Southern Western Ghats

We analyze the structure and composition of old-growth wet evergreen forest of Nelliampathy hills, the chain of hills lying immediately south of Palghat Gap, in the southern Western Ghats of India. We sampled 30 plots of 0.1 ha each (50m×20m) at six locations enumerating all plants≥10cm girth at breast height. We pooled the data and computed various structural parameters. There were 152 species of 120 genera and 51 families of the study area. Of these, 118 (77%) were trees, 24 were climbers (16%) and 10 were shrubs (7%). Species richness varied from 58 99 per 0.5 ha sample and Shannon indices of diversity ranged from 4.4 to 5.2. Fifty-nine per cent (89 species) of the species were Indian Sub-continent elements and 34% (51 species) are endemic to the Western Ghats. Fifteen species are listed in various threat categories. Aglaia and Litsea were the most species-rich genera. Numbers of families ranged from 27 43 per 0.5 ha sample. Euphorbiaceae and Lauraceae were the most species-rich families. Stand density varied from 1714 to 2244 stems·ha -1 and basal area from 53.6 to 102.1 m 2 ·ha -1 . The vegetation was dominated by 3 6 species and six dominance patterns characterized the species composition within the hill complex. The old-growth evergreen forests of Nelliampathy exist as small fragments rich in biodiversity and can be used as benchmarks for comparison with disturbed forests.     

Structure and floristic composition of tree stand in tropical forest in the Eastern Ghats of northern Andhra Pradesh,India

The changes in species composition, abundance and forest stand structure were analyzed across altitudinal regimes in tropical for- ests of Eastern Ghats of northern Andhra Pradesh, India. Three 1-ha plots were established with one each in low, medium and high altitudes. A total of 153 species, 2129 stems (709 stems ·ha -1 ) of ≥10 cm girth were enumerated. Species richness and diversity pattern varied along altitud- inal gradient and increased with the altitude. Species richness varied from 52 to 110 species·ha -1 and stand density from 639 to 836 stems·ha -1 with average basal area of 34.39 m 2 ·ha -1 . Shannon-Wiener index (H’) ranged from 4.55 to 5.17. Low altitude (i.e., Site 1) is dominated by Xylia xylocarpa (59.22) and Lagerstroemia parviflora (23.90), medium altitude (i.e., Site 2) by Xylia xylocarpa (45.50) Bursera serrata (17.29), and high altitude (i.e., Site 3) has Schleichera oleosa (28.25) Pterocarpus marsu- pium (26.55) as predominant species. Taxonomically, Rubiaceae (12 species), Fabaceae (12), Euphorbiaceae (11), Rutaceae (7) and Lauraceae (7) were dominant families. Density-wise, Fabaceae, Combretaceae, Euphorbiaceae, Anacardiaceae and Myrtaceae were abundant. Thus, conservation assessment based on altitudinal regimes and the information on species structure and function can provide baseline information for monitoring and sustaining the biodiversity.     

Effects of treefall gaps created by windthrow on bat assemblages in a temperate forest

Determining the way in which spatial distribution and diversity of forest-dwelling mammals varies with natural disturbance is essential to understanding the spatial dynamics of mammal assemblages in forests. Bats are the only forest-dwelling mammals capable of true flight. At a local scale, bat flight ability, which may be related to ecomorphological traits, is an important factor influencing spatial distribution. We tested two postulates: (1) the spatial distribution of bats is affected by sizes of forest gaps created by natural disturbances and (2) species-specific responses can be predicted from bat ecomorphological traits (aspect ratio (AR) and wingtip shape index (WT)) that influence bat flight ability. We found that sizes of forest gaps affected the occurrence of each bat species and species richness of bats at local scales; species-specific responses were related to the ecomorphological traits of individual species. Bat species with high AR and low WT were not affected by variation in canopy gap size. In contrast, bat species with low AR and high WT responded negatively to gap size, and those with intermediate AR and WT responded positively to canopy gap size at sites with small-sized gaps but responded negatively to large-sized gaps. Overall bat species richness responded negatively to gap size. Thus, ecomorphological traits may be important determinants of bat spatial distributions and species diversity at local scales in disturbed habitats. In this study, forest edges might have been undersampled due to the location of bat detectors. However, this potential undersampling should not have affected the interpretation of occurrence patterns of bat species responding to gap size. Our results imply that bat conservation efforts in forest lands should take into consideration specific responses related to ecomorphological traits of species inhabiting an area. The results also suggest that quantifying the effects of natural disturbances on bat assemblages may provide a knowledge base for forest management to minimize the impacts of unavoidable anthropogenic disturbances on bat species diversity. Rare or infrequent natural disturbances can provide models for forest management aimed at maintaining bat species diversity.     

Secondary forest floristic composition, structure, and spatial pattern in subtropical China

Secondary evergreen broadleaved forests are precious remnants for biodiversity conservation and templates for sustainable management of natural forests in subtropical China. Floristic composition, size structure, and spatial pattern of dominant tree species have been investigated for a subtropical secondary evergreen broadleaved forest in the Huitong Yingzuijie National Forest Reserve, Hunan, China. The location of all trees greater than 4 cm in diameter at breast height (DBH) were mapped within a 0.96-ha plot in which species, DBH, and total tree height were recorded. Ripley’s K(t) function was used to analyze spatial patterns and associations. The secondary forest consisted of 74 tree species and 1,596 stems per hectare. A reverse-J shaped DBH classes distribution was observed for all stems and trees of later seral species whereas trees of earlier successional species were distributed irregularly. Significant aggregated spatial patterns were observed for all trees within the forest and for conspecific trees of each dominant species. This result, and a repulsive spatial pattern for interspecific trees of Choerospondias axillaries and Cyclobalanopsis glauca against other dominant tree species, support segregation hypothesis. Contributions of seed dispersal, topographic heterogeneity, and competition to spatial patterns of conspecific trees vary depending on tree species. Attractive spatial pattern among interspecific trees of Liquidambar fortunei, Liquidambar formosana, and Pinus massoniana reflects stochastic colonization of pioneer tree species and a facilitation relationship. Although deciduous species are long-lived and persist over long successional processes, they will eventually be replaced by late seral evergreen species within the secondary forest if no disturbance events occur.     

Pasture floristic composition in different Eucalyptus species plantations in some parts of northern Guinea savanna zone of Nigeria

In view of the recurrent drought and human population pressures which have drastically reduced the density of pasture species within the Nigerian savannas, the nomadic herdsmen rely mostly on silvipastoralism, grazing their herds in Eucalyptus plantations. In this study, the population of understorey forage and non-forage speicies and the relative light intensities on the forest floors of two Eucalyptus species, viz: E. citridodora, and E. camaldlensis were compared with those of open savanna lands at Kabama, Samaru and Guga, all within the Northern Guinea savanna zone.At normal 3 m by 3 m spacing between trees, the herbages were fewer in the plantations and the E. citridora plantation had only about half the number of species observed under E. camaldlensis in the same and other sites despite similarities in light intensity levels in all the plantations. This information forms a guideline in using eucalyptus silvo-pastoral farms.     

Modelling drainage fluxes in managed and natural forests in the Dinaric karst: a model comparison study

Two models for calculating the forest water balance were applied to different development stages of managed and non-managed forests in the Dinaric Karst for two hydrologically contrasting growing seasons. A simple model WATBAL, which calculates water balance on a monthly basis, and the BROOK90 model, which calculates water balance on daily basis, were used. Differences between calculated drainage fluxes between the models were less pronounced in the drier growing season and were lower in the forest stands compared to forest gaps. Average calculated drainage fluxes of the two growing seasons were highest in the gaps and lowest in the stand in the virgin forest remnant, followed by the mature stand in the managed forest. According to model fitting, testing the calibration robustness and sensitivity analysis the BROOK90 model was considered best at simulating the water balance of the various research sites. The difference in model behaviour is considered to be mainly the result of the difference in model time step and the inclusion of macropore flow in BROOK90. The greater complexity of the BROOK90 model meant it could be parameterized to describe more fully the complexity of the horizontal and vertical structure of forest stand and soil properties. A disadvantage of the BROOK90 model is the greater need of input data. WATBAL, however, was useful for obtaining rougher estimates of the water balance components and can be applied to areas where there is less data available. Choice of model is therefore determined by data availability.     

Nutrient distribution and accumulation patterns of natural secondary forests in the Loess Plateau of Shanxi Province, northern China

We studied the biomass and its allocation in natural secondary forests, as well as the amounts, accumulation and distribution of nutrient elements (N, P, K, Ca and Mg) in sample plots established in the Loess Plateau in Shanxi Province, northern China. The results show that biomass in natural secondary forests amounted to 36.09 t/hm², of which the tree layer accounted for 46%, the shrub layer for 29%, the herb layer for 13% and the litter layer for 12%. The total storage of the five nutrient elements is 1089.82 kg/hm². Nutrient storage in the tree layer is the largest, at 41%. The sequence of storage of the elements varied among different layers and is given as follows: shrub layer 31.27%, herb layer 12.55% and litter layer 15.36%. The accumulation of nutrient elements in the tree layer, ordered from high to low, is: branches > roots > stems >bark > leaves. The total storage of the five nutrient elements in the soil is 634.97 t/hm², where the accumulation of the nutrients accounts for 95.32% (N), 99.64% (P), 99.91% (K), 99.84% (Ca) and 99.95% (Mg) of the total amounts. The accumulation coefficients of different organs in the tree layer are, from high to low: leaves > branches > roots > bark > stems. The accumulation coefficients in the different layers are listed as follows: shrub layer > tree layer > herb layer and for the elements as: N > P > Ca > K > Mg. __________ Translated from Journal of Beijing Forestry University, 2008, 30(3): 57–62 [译自: 北京林业大学学报]     

Effects of management on coarse woody debris volume and composition in boreal forests in northern Sweden

Forest management practices have led to a reduction in the volume and a change in the composition of coarse woody debris (CWD) in many forest types. This study compared CWD volume and composition in reserves and two types of managed forest in the central boreal zone of Sweden. Ten areas were surveyed, each containing clear-cut, mature managed and old-growth stands, to determine the volume of standing and lying CWD in terms of species composition, decay class and size class. Volumes of CWD on clear-cuts and in mature managed forests were high compared with previous studies. Old-growth forests (72.6 m³ ha^?1) contained a greater volume of CWD than mature managed forests (23.3 m³ ha^?1) and clear-cuts (13.6 m³ ha^?1). Differences were greatest for the larger size classes and intermediate decay stages. Despite stand ages being up to 144 years, CWD volume and composition in managed forests was more similar to clear-cuts than to old-growth forests.     

Recovery of floristic diversity,composition and structure of regrowth forests on fallow lands: implications for conservation and restoration of degraded forest lands in Laos

New Forests - In Laos, there are extensive shifting cultivation areas and regrowth forests spontaneously established on fallow lands. The aims of the study were to conduct a comparative study of...     

Biomass storage in low timber productivity Mediterranean forests managed after natural post-fire regeneration in south-eastern Spain

Despite the low timber productivity of Mediterranean Pinus halepensis Mill. forests in south-eastern Spain, they are a valuable carbon sequestration source which could be extended if young stands and understories were considered. We monitored changes in biomass storage of young Aleppo pine stands naturally regenerated after wildfires, with a diachronic approach from 5 to 16 years old, including pine and understory strata, at two different quality sites (dry and semiarid climates). At each site, we set 21 permanent plots and carried out different thinning intensities at two ages, 5 and 10 years after fires. We found similar post-fire regeneration capacity at both sites in terms of total above-ground biomass storage ~6 Mg ha^?1 (3 Mg ha^?1 of the above-ground pine biomass plus 3 Mg ha^?1 of the above-ground understory biomass), but with a contrasting pine layer structure. Generally, across the diachronic study, the earlier thinning reduced biomass stocks at both sites, except for the best quality site (the dry site), where the earliest thinning (applied at post-fire year 5) enlarged carbon storage by 11 % as compared to non-thinned plots. We found root:shoot ratios of an average 0.37 for the pine layer and 0.45 for the understory layer. These results provided new information which not only furthers our understanding of carbon sequestration in low timber productivity Mediterranean forests, but will also help to develop new guidelines for sustainable management adapted to the high-risk terrestrial carbon losses of fire-prone areas.     

Deciduous trees affect small-scale floristic diversity and tree regeneration in conifer forests

Abstract

There is a growing interest in the effects of deciduous trees on biodiversity, soil processes and long-term productivity in boreal, conifer-dominated forests. This study investigated whether individual birch trees allowed to grow to maturity in the coniferous forest can have a local effect on floristic richness and regeneration of tree saplings. The ground vegetation was compared in 2?m radius plots around the stem under the canopies of matched conifer–deciduous trees in a mature, conifer-dominated forest, and included in the analysis variables that could potentially mediate the tree effect (soil pH, cover of lichens, bryophytes, leaf and needle litter). The field layer vegetation was more species rich under birch (Betula pendula and B. pubescens) than under conifers (Picea abies and Pinus sylvestris), and several vascular plant species (including saplings of tree species) occurred more often under birch than under conifers. However, when the effect of the number of subordinate trees was taken into account the difference between birch and pine was not significant. The number of tree regenerations (saplings) was lowest under pines, but did not differ between spruce and birch. There were no effects of the canopy species on soil pH or on cover of lichens and bryophytes. The difference in diversity may be caused by the different effects of leaf and needle litter, and it is also likely that canopy structure has an influence via interception and throughfall and by affecting the light and microclimate.     

Adoption of mucuna in the farming systems of northern Honduras

In many parts of Central America long fallow periods are no longer feasible due to increasing land pressures. Farmers in northern Honduras have developed and diffused from farmer-to-farmer a maize cropping system using velvetbean (Mucuna spp.) as a short-term fallow. High total annual rainfall in a bimodal distribution is favorable to the system because it allows the completion of two rainfed cropping cycles annually. The first season is dedicated to the production of the mucuna crop and the second season is dedicated to maize. Soil pH and exchangeable Ca were not reduced during a 15-year period of continuous mucuna use. Soil organic matter, infiltration, and porosity increased with continuous mucuna use. Maize yields in fields with continuous rotation of mucuna were on average double those obtained without mucuna. The mucuna system was more profitable than the existing alternative bush-fallow system due to higher returns to land and labor resulting from higher yields, lower weeding and land preparation costs, and reduced risk of drought stress. The relative profitability of the mucuna system was also enhanced by seasonally high maize prices during the second season when maize is harvested in the mucuna system. Relatively easy access to land through inexpensive land ownership and land rental markets has made it possible for even small-scale farmers to dedicate land to the mucuna system. Land-use intensity is increasing in the region, however, as land is converted to pastures for cattle production. The opportunity costs of keeping land in the mucuna system, while also accessing land for first-season maize and other crops, are also increasing. These experiences remind us that a viable livelihood is the primary factor in farmers' decision making about adoption particular components of farming systems.This revised version was published online in November 2005 with corrections to the Cover Date.     

A floristic survey of the Hyrcanian forests in Northern Iran,using two lowland-mountain transects

We investigated the floristic composition of the Hyrcanian forests and the related forest-steppe ecotone in Northern Iran by using two long ecological transects, from lowland to upper mountain areas. The study was conducted during 2008 and 2009 and yielded the identification of 395 plant taxa belonging to 233 genera and 78 families. Dicots with 300 taxa were the richest groups of the flora, followed by monocots with 75 taxa, pteridophytes with 18 species,and gymnosperms with two species. The largest families were Asteraceae(33 taxa); Rosaceae(32 taxa); and Poaceae(30 taxa), and the most diverse genera included Carex(15 taxa); Alchemilla(7 taxa); and Poa, Geranium and Acer(6 taxa each). Hemicryptophytes were the most dominant life forms in the area(40 %); followed by geophytes(31.4 %); phanerophytes(15.4 %); therophytes(11.4 %); and chamaephytes(1.8 %). Phytogeographically,Euro-Siberian/Irano-Turanian elements(86 taxa, 21.8 %)and Euro-Siberian elements(85 taxa, 21.5 %) were the most common chorotypes in the area. Out of 395 taxa, 66taxa(16.7 %) were endemics and subendemics in Iran, of which 26 taxa were exclusively endemics of Iran.According to the IUCN Red List Categories, 48 threatened plant taxa were found in the study area. Plant diversity, life form, and chorotypes in the current study were compared with similar transect studies in other areas of the Hyrcanian forests and in different altitudinal belts, using S?renson similarity indices. Floristic composition of the surveyed transects demonstrated almost 50 % similarity between them.     

Characteristics and dynamics of sandy natural forests in sandy forest-steppe ecotone in the northern area of China

l "trod notionViolent human disturbance results in global landscape and vegetation fragmentation, including thepolar landscape and alpine vegetation (Cox, 1993).In modern world, environment and development aretWo important problems, which have a direct effecton the destiny of human and the earth. Forestry,which undertakes double missions that are to optimize the environment and promote the development,is the crux to realize the unity of environment anddevelopment (Liu 1985).China is a develop…     

Soil community composition and ecosystem processes: Comparing agricultural ecosystems with natural ecosystems

Soil organisms play principal roles in several ecosystem functions, i.e. promoting plant productivity, enhancing water relations, regulating nutrient mineralisation, permitting decomposition, and acting as an environmental buffer. Agricultural soils would more closely resemble soils of natural ecosystems if management practices would reduce or eliminate cultivation, heavy machinery, and general biocides; incorporate perennial crops and organic material; and synchronise nutrient release and water availability with plant demand. In order to achieve these goals, research must be completed to develop methods for successful application of organic materials and associated micro-organisms, synchronisation of management practices with crop and soil biota phenology, and improve our knowledge of the mechanisms linking species to ecosystem processes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Ecology of Armillaria species in managed forests and plantations in Serbia

The distribution of Armillaria species was investigated in Serbian forest ecosystems, in relation to the main host species attacked, forest‐types, geography and altitude. In total, 388 isolates were identified from 36 host species in 47 sites. Armillaria gallica was the most commonly observed species with the widest distribution and with an altitudinal range of 70–1450 m, it was the dominating Armillaria species in lowland alluvial forests and in Quercus and Fagus forests at higher elevations. Armillaria mellea occurred in Quercus spp. – dominated forests in the north and central regions at 70–1050 m. Sixty‐eight per cent of the A. mellea isolates were collected from living hosts, most commonly in declining conifer plantations. Armillaria ostoyae was distributed in the cooler coniferous forest types and plantations in the Dinaric Alps in the south of Serbia, at 850–1820 m. Armillaria cepistipes was found in the eastern and southern hilly and mountainous regions of the country, at 600–1900 m. Most isolates were obtained from conifers and rhizomorphs in the soil around decaying stumps. Armillaria tabescens was found only on dead oak material in the northern and eastern regions of the country at altitudes lower than 600 m.     

Stand development patterns of forest cover types in the natural forests of northern Baekdudaegan in South Korea

The purpose of this study was to classify current forest cover types,and to investigate stand development patterns for natural forests in six areas in northern Baekdudaegan,South Korea.Twenty-eight independent forest communities were aggregated into eight forest cover types by species composition in the overstory of each forest community.The forest cover types were of mixed mesophytic,‘‘others’ ’ deciduous,Quercus mongolica dominant,Q.mongolica pure,Pinus densiflora–Q.mongolica,P.densiflora,Betula ermanii,and Q.mongolica–P.koraiensis.The ecological information was organized by importance value and species diversity for each forest type.Based on the correlation between species diversity index and the abundance of Q.mongolica plus P.densiflora for corresponding forest cover types,we compared the developmental process and approximate successional pathway between each cover type.The P.densiflora forest cover type changes into the P.densiflora–Q.mongolica cover type,followed by the Q.mongolica dominant cover type through continuous invasion of the oak trees.Furthermore,the Q.mongolica pure cover type would spread toward the Q.mongolica dominant cover type with a mixture of various deciduous tree species.The Q.mongolica dominant cover type progresses through the other deciduous cover types to the mixed mesophytic cover type with diversified composition and structure.On the mid to lower slopes,with loamy soils and good moisture conditions,various deciduous forest types should progress,by ecological succession,toward the mixed mesophytic cover type without any further disturbance.