Browse Subjects:
- arboriculture
- forest ecology
- forest economics
- forest engineering
- forest genetics
- forest health
- forest policy
- forest products
- forest recreation
- forest resources
- forest trees
- forestry
- agroforestry
- community forestry
- demonstration forests
- forest inventory
- forest management
- forest mensuration
- forestry development
- plantation forestry
- private forestry
- silviculture
- social forestry
- sustainable forestry
- tropical and subtropical forestry
- urban forestry
- forestry law
- forests
Browse subject: lowland forests
Number of records: 44
Assessment of C-band synthetic aperture radar data for mapping and monitoring Coastal Plain forested wetlands in the Mid-Atlantic Region, U.S.A.
About this Resource: Multi-temporal C-band SAR data (C-HH and C-VV), collected by ERS-2 and ENVISAT satellite systems, are compared with field observations of hydrology (i.e., inundation and soil moisture) and National Wetland Inventory maps (U.S. Fish and Wildlife Service) of a large forested wetland complex adjacent to the Patuxent and Middle Patuxent Rivers, tributaries of the Chesapeake Bay. Multi-temporal C-band SAR data were shown to be capable of mapping forested wetlands and monitoring hydroperiod (i.e., temporal fluctuations in inundation and soil moisture) at the study site, and the discrimination of wetland from upland was improved with 10 m digital elevation data. Principal component analysis was used to summarize the multi-temporal SAR data sets and to isolate the dominant temporal trend in inundation and soil moisture (i.e., relative hydroperiod). Significant positive, linear correlations were found between the first principal component and percent area flooded and soil moisture. The correlation (r2) between the first principal component (PC1) of multi-temporal C-HH SAR data and average soil moisture was 0.88 (p = < .0001) during the leaf-off season and 0.87 (p = < .0001) during the leaf-on season, while the correlation between PC1 and average percent area inundated was 0.82 (p = < .0001) and 0.47 (p = .0016) during the leaf-off and leaf-on seasons, respectively. When compared to field data, the SAR forested wetland maps identified areas that were flooded for 25% of the time with 63-96% agreement and areas flooded for 5% of the time with 44-89% agreement, depending on polarization and time of year. The results are encouraging and justify further studies to attempt to quantify the relative SAR-derived hydroperiod classes in terms of physical variables and also to test the application of SAR data to more diverse landscapes at a broader scale. The present evidence suggests that the SAR data will significantly improve routine wooded wetland mapping.
Bottomland hardwood forest recovery following tornado disturbance and salvage logging
About this Resource: Catastrophic wind events, including tornado, hurricane, and linear winds, are significant disturbances in temperate forested wetlands. Information is lacking on how post-disturbance salvage logging may impact short and long-term objectives in conservation areas where natural stands are typically managed passively. Woody regeneration and herbaceous cover were assessed for three years in a bottomland hardwood forest across a gradient of damage from an F4 tornado, with and without subsequent salvage logging. Soil disturbance intensity and recovery associated with salvage logging within wind-disturbed sites were also assessed. Woody stem density and proportion of potential overstory species (species with the potential to occupy a position in the canopy) increased as a function of wind disturbance intensity. Stem density, proportion of overstory trees, or species diversity did not differ between wind+salvage and wind-disturbed-only plots. Significant dissimilarity occurred among soil disturbance classes within salvaged sites. By the third growing season, vegetation in soil disturbance classes in wind+salvage areas was converging toward undisturbed conditions and bottomland hardwood forest recovery was underway in all vegetation disturbance types and soil disturbance classes. Post-tornado salvage logging, applied judiciously, may contribute to microsite and vegetation diversity.
Effects of reduced-impact logging and forest physiognomy on bat populations of lowland Amazonian forest
About this Resource: 1. As human population size increases, demand for natural resources will increase. Logging pressure related to increasing demands continues to threaten remote areas of Amazonian forest. A harvest protocol is required to provide renewable timber resources that meet consumer needs while minimizing negative effects on biodiversity and ecosystem services. Reduced-impact logging (RIL) may be a viable option to achieve these goals. 2. Effects of RIL (18 m³ ha⁻¹) and forest physiognomy were assessed for populations of bats from Amazonian terra firme forest in Brazil at 20-42 months postharvest. 3. Based on 64 512 meter-hours of netting, 1468 bats were captured representing 47 species, 30 genera, four families and five feeding ensembles. Five species (one nectarivore and four frugivores) responded to management in a consistent manner: four were more abundant in logged forest and one was more abundant in undisturbed forest. Ten species (one nectarivore, two gleaning animalivores and seven frugivores) responded to forest physiognomy in a consistent manner: nine were more abundant in closed-canopy sites and one was more abundant in gaps. Three species (all frugivores) exhibited idiosyncratic responses to management that were contingent on physiognomy. 4. Using qualitative measures (changes in status from common to rare, or from present to absent), RIL elicited negative responses from 16 species, mostly rare taxa. After accounting for differences in total number of collected individuals, control forest harboured seven to 15 more rare species than did forest subjected to RIL. 5. Synthesis and applications. In the short term, RIL generally did not negatively affect populations of abundant bats. In contrast, reductions in abundance or local extirpation in response to RIL generally characterized uncommon or rare species. Arrangement of RIL sites in a matrix of undisturbed forest may allow source-sink dynamics to mitigate effects of RIL on rare or sensitive species and enhance sustainability at a regional scale.
Five-year radial growth of red oaks in mixed bottomland hardwood stands
About this Resource: We studied the relationships among 5-year radial (diameter and basal area) growth of red oak (genus Quercus, subgenus Erythrobalanus) crop trees and predictor variables representing individual tree vigor, distance-dependant competition measures, and distance-independent competition measures. The red oaks we examined are representative of the commercially and ecologically important oak species of the bottomland hardwood forests of the southeastern US. The crown class score, a quantitative measure of crown class and tree vigor, performed best in accounting for the variability in tree diameter growth. Plot-level variables failed to account for a significant proportion of the variability in tree radial growth. The basal area of the first-order neighbors that were taller than the crop trees and located within 2.4 times the mean overstory crown radius had the highest negative correlation with crop tree 5-year radial growth. Red oaks were a major part of these competitors and likely exerted the greatest competitive pressure. However, crop tree radial growth was positively associated with the basal area of the red oaks which were indirect (second order) neighbors and which were taller than the crop trees. It is possible that indirect neighbors do not compete with the crop trees, but they likely compete with the direct competitors of the crop trees, thus having an indirect positive influence on crop tree growth. Such reasoning is consistent with previously observed spatial dependence up to four times the mean overstory crown radius. The findings may have implications for thinning hardwoods stands and crop tree management in that foresters need to take into account (1) oak intra-genus competition, (2) the negative competitive effect of direct neighbors, and (3) the potentially positive effect of the indirect neighbors, the competitors' competitors.
The response of ground beetles (Coleoptera: Carabidae) to selection cutting in a South Carolina bottomland hardwood forest
About this Resource: We compared the response of ground beetles (Coleoptera: Carabidae) to the creation of canopy gaps of different size (0.13, 0.26, and 0.50 ha) and age (1 and 7 years) in a bottomland hardwood forest (South Carolina, USA). Samples were collected four times in 2001 by malaise and pitfall traps placed at the center and edge of each gap, and 50 m into the surrounding forest. Species richness was higher at the center of young gaps than in old gaps or in the forest, but there was no statistical difference in species richness between old gaps and the forests surrounding them. Carabid abundance followed the same trend, but only with the exclusion of Semiardistomis viridis (Say), a very abundant species that differed in its response to gap age compared to most other species. The carabid assemblage at the gap edge was very similar to that of the forest, and there appeared to be no distinct edge community. Species known to occur in open or disturbed habitats were more abundant at the center of young gaps than at any other location. Generalist species were relatively unaffected by the disturbance, but one species (Dicaelus dilatatus Say) was significantly less abundant at the centers of young gaps. Forest inhabiting species were less abundant at the centers of old gaps than in the forest, but not in the centers of young gaps. Comparison of community similarity at various trapping locations showed that communities at the centers of old and young gaps had the lowest similarity (46.5%). The community similarity between young gap centers and nearby forest (49.1%) and old gap centers and nearby forest (50.0%) was similarly low. These results show that while the abundance and richness of carabids in old gaps was similar to that of the surrounding forest, the species composition between the two sites differed greatly.
Short-Term Responses of Birds to Forest Gaps and Understory: An Assessment of Reduced-Impact Logging in a Lowland Amazon Forest
About this Resource: We studied physiognomy-specific (i.e., gaps vs. understory) responses of birds to low harvest (18.7 m³[solidus]ha), reduced-impact logging by comparing 3500 mist net captures in control and cut blocks of an Amazonian terra firme forest in Brazil at 20-42 mo postharvest. Species richness did not differ significantly between control (92 species) and cut (85) forest based on rarefaction to 1200 captures. Fifty-six percent of all species were shared between control and cut forest, compared to the 64 percent shared between control blocks. Higher captures of nectarivores and frugivores in cut forest likely occurred as a consequence of postharvest resource blooms. Higher captures of some insectivores in cut as compared to control forest were unexpected, attributable to increased wandering or shifts from association with midstory to understory as a consequence of habitat alteration. Logging influenced capture rates for 21 species, either consistently, or via positive interaction with physiognomy or time (13 species higher in cut forest and 8 species higher in control forest). Cut understory sites had lower diversity (H[prime]) and scaled dominance than understory and gap sites in control forest. Temporal changes in captures may have resulted from successional dynamics in cut forest: two guilds and three species increased in abundance. Increases in abundances of guilds and particular species were more prevalent in control than in cut forest, suggesting that logging displaced birds to control forest. In general, the effects of logging were relatively minor; low harvest rates and reduced-impact methods may help to retain aspects of avian biodiversity in Amazon forest understories.
Litterfall in the hardwood forest of a minor alluvial-floodplain
About this Resource: Within mature deciduous forests, annual development of foliar biomass is a major component of aboveground net primary production and nutrient demand. As litterfall, this same foliage becomes a dominant annual transfer of biomass and nutrients to the detritus pathway. We report litterfall transfers of a mature bottomland hardwood forest in a minor alluvial-floodplain within the middle Coastal Plain physiographic province of central Louisiana, USA. Climate is humid subtropical. Floodplain forests of minor alluvial-streams may account for nearly half the remaining acreage of bottomland forests in the Southeastern USA and differ markedly from those of major alluvial-rivers and deep-water swamps. For a 3-year period, litterfall magnitude, components, leaf species, and timing were monitored by monthly collection of materials from litterfall collectors. Variations in litterfall transfers across 10 study-plots and their relationships to forest parameters are evaluated. Mean transfers of total litterfall, leaf fall, reproductive structures, fine wood, and other litterfall were 816, 512, 130, 98, and 76 g m-2 year-1, respectively. Quercus pagoda Raf., Q. nigra L., and Liquidambar styraciflua L. accounted for an average of 49% of annual leaf fall, with 11 tree species and canopy vines accounting for 94% of total annual leaf fall. A total of 38 species and genera contributed to total leaf fall. Variation in total litterfall and leaf fall transfers across the alluvial bottom were related to size of overstory trees and their species composition. Higher and more consistent mass transfers of reproductive structures were observed than previously reported for upland hardwood stands.
Invasive plants transform the three-dimensional structure of rain forests
About this Resource: Biological invasions contribute to global environmental change, but the dynamics and consequences of most invasions are difficult to assess at regional scales. We deployed an airborne remote sensing system that mapped the location and impacts of five highly invasive plant species across 221,875 ha of Hawaiian ecosystems, identifying four distinct ways that these species transform the three-dimensional (3D) structure of native rain forests. In lowland to montane forests, three invasive tree species replace native midcanopy and understory plants, whereas one understory invader excludes native species at the ground level. A fifth invasive nitrogen-fixing tree, in combination with a midcanopy alien tree, replaces native plants at all canopy levels in lowland forests. We conclude that this diverse array of alien plant species, each representing a different growth form or functional type, is changing the fundamental 3D structure of native Hawaiian rain forests. Our work also demonstrates how an airborne mapping strategy can identify and track the spread of certain invasive plant species, determine ecological consequences of their proliferation, and provide detailed geographic information to conservation and management efforts.
Drainage and agriculture impacts on fire frequency in a southern Illinois forested bottomland
About this Resource: Postsettlement (1909-2003) fire history of a forested bottomland in the Mississippi Embayment of southern Illinois, USA, was determined using fire-scar analysis. The study area is a forested bottomland hardwood site, with remnant pockets of the dominant presettlement bald cypress - tupelo (Taxodium-Nyssa) vegetation. Ditch drainage was installed in 1919, with agricultural clearing and abandonment varying throughout the early and mid-twentieth century. Commercial agricultural activities ceased after the site became part of a conservation area ca. 1950. The hydrology of the site was further modified in 1957 when it was inundated for waterfowl management. Both drainage and land clearing for agriculture were associated with increased fire frequency. Although drainage was a necessary precursor to agriculture across much of this landscape, land improvement played the stronger role in determining fire frequency. The mean fire interval for the study period (1895-1965) was 1.73 years, with a minimum of 1 year and a maximum of 15 years. This frequency contrasts with the complete fire exclusion that has prevailed in the area since 1965. These results have important implications for the maintenance and restoration of forested wetland ecosystems where the present fire regime differs dramatically from that under which the now-dominant forest vegetation developed.
Invasive litter, not an invasive insectivore, determines invertebrate communities in Hawaiian forests
About this Resource: In Hawaii, invasive plants have the ability to alter litter-based food chains because they often have litter traits that differ from native species. Additionally, abundant invasive predators, especially those representing new trophic levels, can reduce prey. The relative importance of these two processes on the litter invertebrate community in Hawaii is important, because they could affect the large number of endemic and endangered invertebrates. We determined the relative importance of litter resources, represented by leaf litter of two trees, an invasive nitrogen-fixer, Falcataria moluccana, and a native tree, Metrosideros polymorpha, and predation of an invasive terrestrial frog, Eleutherodactylus coqui, on leaf litter invertebrate abundance and composition. Principle component analysis revealed that F. moluccana litter creates an invertebrate community that greatly differs from that found in M. polymorpha litter. We found that F. moluccana increased the abundance of non-native fragmenters (Amphipoda and Isopoda) by 400% and non-native predaceous ants (Hymenoptera: Formicidae) by 200%. E. coqui had less effect on the litter invertebrate community; it reduced microbivores by 40% in F. moluccana and non-native ants by 30% across litter types. E. coqui stomach contents were similar in abundance and composition in both litter treatments, despite dramatic differences in the invertebrate community. Additionally, our results suggest that invertebrate community differences between litter types did not cascade to influence E. coqui growth or survivorship. In conclusion, it appears that an invasive nitrogen-fixing tree species has a greater influence on litter invertebrate community abundance and composition than the invasive predator, E. coqui.
Herbivorous insect response to group selection cutting in a southeastern bottomland hardwood forest.
About this Resource: Malaise and pitfall traps were used to sample herbivorous insects in canopy gaps created by group-selection cutting in a bottomland hardwood forest in South Carolina. The traps were placed at the centers, edges, and in the forest adjacent to gaps of different sizes (0.13, 0.26, and 0.50 ha) and ages (1 and 7 yr old) during four sampling periods in 2001. Overall, the abundance and species richness of insect herbivores were greater at the centers of young gaps than at the edge of young gaps or in the forest surrounding young gaps. There were no differences in abundance or species richness among old gap locations (i.e., centers, edges, and forest), and we collected significantly more insects in young gaps than old gaps. The insect communities in old gaps were more similar to the forests surrounding them than young gap communities were to their respective forest locations, but the insect communities in the two forests locations (surrounding young and old gaps) had the highest percent similarity of all. Although both abundance and richness increased in the centers of young gaps with increasing gap size, these differences were not significant. We attribute the increased numbers of herbivorous insects to the greater abundance of herbaceous plants available in young gaps.
Seasonal and spatial distributions of adult screwworms (Diptera: Calliphoridae) in the Panama Canal area, Republic of Panama.
About this Resource: The distribution of screwworms, Cochliomyia hominivorax, (Coquerel) was studied in a seasonally moist lowland tropical forest in the Republic of Panama using a combination of field collections and satellite imagery. We found that different forest types could be distinguished and mapped using remotely sensed data. To determine the temporal and spatial distribution of flies, we collected flies coming to rotted liver at 82 sites in ten vegetation types (open areas, edge forest, dry scrub forest, forest successional stage 1, forest successional stage 2, forest successional stage 3, forest successional stage 4, forest successional stage 5, mature forests, palm swamp forest, and forest along streams) over three seasons (dry, transitional, wet). Nine of the vegetation types (excluding dry scrub forest) were identified and mapped using SPOT XS and Landsat 5 TM satellite data. Screwworm flies were most abundant during the transition from wet to dry season. Fly numbers were consistently higher in forest habitats, particularly those with trees 20-30 m in height and a fairly open canopy composed of many deciduous species that shed their leaves during the dry season. Screwworm numbers were also high in palm swamp forest, edge forest, and mature growth forest. Traps sampled in open areas had fewer flies and were unrelated to proximity to cattle. Females accounted for 88% of the total fly counts. This study further substantiates the importance of forests in the ecology and behavior of screwworm flies and demonstrates that remotely sensed data can be used to construct the spatial distribution of these flies in a tropical landscape. We discuss implications of this information to the screwworm eradication program.
Patterns of Primary Succession of Native and Introduced Plants in Lowland Wet Forests in Eastern Hawai'i
About this Resource: The majority of Hawaii's lowland wet forests no longer exist, with many of the last remaining patches found on the eastern, windward sides of the largest islands. To better understand successional patterns and invasion in these native systems, we quantified basal area (BA) and densities of woody species and understory cover at nine sites in the Puna district on the Island of Hawai'i, representing age gradients of native stand development on both 'a'ā and pāhoehoe lava flows. On both flow types, BA of native species increased (from 5 to 50 m²/ha) and stem densities decreased (from 3700 to 2600 stems/ha) with increasing stand/flow age. Both native and introduced species compositions diverged between substrate types on older flows. We found that lowland wet native forests remain at least partially intact in several locations, but their functional and compositional integrity is increasingly compromised by invasion of nonnative species, such as Psidium cattleianum and Melastoma candidum, which become more common at sites greater than 300-yr old. This time period may represent a threshold, after which abiotic environmental conditions no longer constrain recruitment of introduced species. On older flows, nonnative stem densities swamped those of native species by an order of magnitude, with nonnative stems (height > 1.3 m) achieving densities as high as 18,000 stems/ha. In addition, all stands lacked recruitment of native woody species in the understory, suggesting that without management, the native componentsof these forests may soon no longer be self-sustaining.
Understory species richness in an urban forest fragment, Pernambuco, Brazil
About this Resource: This study characterizes the floristic composition of the understory of Parque Estadual de Dois Irmãos, (08°01’15.1”S and 34°56’3.2”W), an area of about 370ha characterized as a lowland ombrophilous dense forest. The study included individuals with heights of up to 4.0m, such as treelets, shrubs, sub-bushes and terricolous herb plants, in fertile conditions. The collections were made every two weeks along a period of 24 months. A total of 108 species, belonging to 86 genera and 49 families, were recorded. The families with the highest number of species were Rubiaceae (14), Fabaceae (9) Melastomataceae (8), Asteraceae (8), Myrtaceae (6), and Poaceae (4). The Fabaceae, Melastomataceae, Myrtaceae and Rubiaceae presented the highest number of understory species in this fragment. Generally, among the studies made in the Atlantic forest areas in Pernambuco, the presence of a set of tree species common to these forests is evidenced.
Influence of incidence angle on detecting flooded forests using C-HH synthetic aperture radar data
About this Resource: Hydrology is the single most important abiotic factor in the formation and functioning of a wetland. Many limitations still exist to accurately characterizing wetland hydrology over large spatial extents, especially in forested wetlands. Imaging radar has emerged as a viable tool for wetland flood mapping, although the limitations of radar data remain uncertain. The influence of incidence angle on the ability to detect flooding in different forest types was examined using C-HH Radarsat-1 data (23.5°, 27.5°, 33.5°, 39.0°, 43.5°, and 47.0°) during the leaf-off and leaf-on seasons. The ability to detect flooding under leaf-on conditions varied much more according to incidence angle while forest type (open canopy tupelo-cypress, tupelo-cypress, and bottomland hardwood) had a greater effect during the leaf-off season. When all forest types were considered together, backscatter generally decreased with increasing incidence angle under all conditions (2.45 dB between 23.5° and 47.0° flooded, leaf-off; 2.28 dB between 23.5° and 47.0° not flooded, leaf-off; 0.62 between 23.5° and 43.5° flooded, leaf-on; 1.73 dB between 23.5° and 43.5° not flooded, leaf-on; slope was not constant between incidence angles), but the distinction between flooded and non-flooded areas did not decline sharply with incidence angle. Differentiation of flooded and non-flooded forests was similar during the leaf-off and leaf-on seasons. The ability to detect inundation under forest canopies was less than expected at smaller incidence angles and greater than expected at larger incidence angles, based on the results of previous studies. Use of a wider range of incidence angles during the entire year increases the temporal resolution of imagery which may, in turn, enhance mapping of inundation beneath forest canopies.
Restoration of bottomland hardwood forests across a treatment intensity gradient
About this Resource: Large-scale restoration of bottomland hardwood forests in the Lower Mississippi Alluvial Valley (USA) under federal incentive programs, begun in the 1990s, initially achieved mixed results. We report here on a comparison of four restoration techniques in terms of survival, accretion of vertical structure, and woody species diversity. The range of treatment intensity allowed us to compare native recolonization to direct seeding and planting of Quercus nuttallii Palmer, and to an intensive treatment of interplanting two species that differed in successional status (early successional Populus deltoides Bartram ex Marsh. ssp. deltoides, with the mid-successional Q. nuttallii). Native recolonization varied in effectiveness by block but overall provided few woody plants. All active restoration methods (planting and direct seeding) were successful in terms of stocking. Populus grew larger than Quercus, reaching canopy closure after 2 years and heights after 2 and 5 years of 6 and 12.7m, respectively. Planted Quercus were significantly larger than direct seeded Quercus in all years, but only averaged 1.4m in height after 5 years. Interplanting did not seem to facilitate development of the Quercus seedlings. The early success of the interplanting technique demonstrated that environmental benefits can be obtained quickly by more intensive efforts. Native recolonization can augment active interventions if limitations to dispersal distance are recognized. These results should provide landowners and managers with the confidence to use techniques of varying intensity to restore ecosystem functions.
Forest Fires in the Insular Caribbean
About this Resource: This paper presents a summary of the forest fire reports in the insular Caribbean derived from both management reports and an analysis of publicly available Moderate Resolution Imaging Spectrodiometer (MODIS) satellite active fire products from the region. A vast difference between the amount of fires reported by land managers and fire points in the MODIS Fire Information for Resource Management System data can be observed. Future research is recommended to better understand the nature of these differences. While there is a general lack of available statistical data on forest fires in the Caribbean, a few general observations can be made: Forest fires occur mainly in dry forest types (500 to 1000 mm of mean annual rainfall). These are also the areas where most human settlements are located. Lowland high forests and montane forests with higher rainfall (1000 and more mm y-1) are less susceptible to forest fire, but they can burn in exceptionally dry years. Most of the dry forest ecosystems in the Caribbean can be considered to be fire-sensitive ecosystems, while the pine forests in the Caribbean (Cuba, Dominican Republic, and the Bahamas) are maintained by wildfires. In fire-sensitive ecosystems, uncontrolled burning often encourages the spread of alien invasive species. A Caribbean Fire Management Cooperation Strategy was developed between 2005 and 2006 under auspices of the Food and Agriculture Organization of the United Nations. This regional strategy aims to strengthen Caribbean fire management networking by encouraging closer collaboration among countries with similar ecological conditions. The strategy for the Caribbean identifies a number of research, training, and management activities to improve wildfire management capacity in the Caribbean.
Habitat associations of saproxylic beetles in the southeastern United States: A comparison of forest types, tree species and wood postures
About this Resource: Saproxylic beetles are highly sensitive to forest management practices that reduce the abundance and variety of dead wood. However, this diverse fauna continues to receive little attention in the southeastern United States even though this region supports some of the most diverse, productive and intensively managed forests in North America. In this replicated three-way factorial experiment, we investigated the habitat associations of saproxylic beetles on the coastal plain of South Carolina. The factors of interest were forest type (upland pine-dominated vs. bottomland hardwood), tree species (Quercus nigra L., Pinus taeda L. and Liquidambar styraciflua L.) and wood posture (standing and downed dead wood, i.e., snags and logs). Wood samples were taken at four positions along each log and snag (lower bole, middle bole, upper bole and crown) ~11 months after the trees were killed and placed in rearing bags to collect emerging beetles. Overall, 33,457 specimens from 52 families and >=250 species emerged. Based on an analysis of covariance, with surface area and bark coverage as covariates, saproxylic beetle species richness differed significantly between forest types as well as between wood postures. There were no significant interactions. Species richness was significantly higher in the upland pine-dominated stand than the bottomland hardwood forest, possibly due to higher light exposure and temperature in upland forests. Although L. styraciflua yielded more beetle species (152) than either Q. nigra (122) or P. taeda (125), there were no significant differences in species richness among tree species. There were also no relationships evident between relative tree abundance and observed or expected beetle species richness. Significantly more beetle species emerged from logs than from snags. However snags had a distinct fauna including several potential canopy specialists. Our results suggest that conservation practices that retain or create entire snags as opposed to high stumps or logs alone will most greatly benefit saproxylic beetles in southeastern forests.
Scale-dependent environmental controls over species composition in Alaskan black spruce communities
About this Resource: The boreal forest is the second largest terrestrial biome, and the black spruce (Picea mariana (Mill.) BSP) forest type occupies a large extent of boreal North America. Black spruce communities occur in a variety of environmental conditions and are especially important in the context of climate change because of underlain permafrost in much of the northern black spruce forests, as well as their adaptation to fire disturbance. We used a classification and ordination approach to describe and name Alaskan black spruce communities and relate them to key environmental variables. We analyzed the relationship of species richness with topographic position and with soil pH using both univariate and multivariate analyses of variance. We also explored the variability in structural, physical, and soil characteristics. We described three black spruce community types and five subtypes based purely on floristic composition. Paludification and topography were the most important gradients explaining species composition for the Fairbanks region (61% variance explained). However, at the scale of interior Alaska, pH, drainage, and productivity were the strongest environmental gradients (81% variance explained). We conclude that species composition of mature black spruce forests in interior Alaska results from the complex interaction of landscape and fire history, soil pH, paludification, permafrost, and topographic position.
Soil organic carbon quality in forested mineral wetlands at different mean annual temperature
About this Resource: Forested mineral soil wetlands (FMSW) store large stocks of soil organic carbon (SOC), but little is known on: (i) whether the quality of SOC stored in these soils (proportion of active versus more resistant SOC compounds) differs from SOC in upland soils; (ii) how the quality of SOC in FMSW varies with mean annual temperature (MAT); and (iii) whether SOC decomposition rates in these environments respond to warming and drying more strongly than those observed in upland soils. To address this substantial knowledge gap, we identified nine FMSW and fifteen paired upland forest sites across three bioregions in North America (sub-alpine in Colorado; north-temperate in Minnesota; and south-temperate in South Carolina) to test the following three hypotheses. First, FMSW store a higher proportion of active SOC compared with upland systems because long anaerobic periods favor the accumulation of labile substrates. Second, in FMSW, SOC quality decreases from cold to warm bioregions because high quality detritus accumulates preferentially at cool sites where decomposition is slow. Finally, decomposition of SOC in FMSW will respond more strongly to warming under aerobic conditions than SOC from upland forest soils because of higher accumulation of active SOC in FMSW. To test these hypotheses, we incubated FMSW and upland forest soils at two constant temperatures (10 and 30 °C) for 525-d under aerobic conditions and constant moisture. In contrast to our first hypothesis, we observed similarly rapid depletion of active SOC compounds at initial stages of incubation across FMSW and upland sites, and across the 525-d incubations we observed overall lower SOC decomposition rates in our FMSW soils. In line with our second hypothesis, and across FMWS and upland soils, we found greater SOC loss in the sub-alpine bioregion than both temperate regions. In contrast to our last hypothesis, we found no difference in the temperature sensitivity (Q10) of SOC decomposition in FMSW and upland forest soils. Critically, total SOC loss (g SOC per g soil) was larger in FMSW because of the large amount of SOC stored in these ecosystems, indicating that despite a lack of difference between FMSW and upland responses, the total release of C from FMSW that could result from global warming may be large.
Status and development of forest harvesting mechanisation in Croatian state forestry
About this Resource: This paper deals with the present status of forest management in the Republic of Croatia with a special reference to forests managed by the company »Hrvatske šume« d.o.o. Zagreb, as well as to aims, tasks and methods of state-owned forest management, to conditions and trends in the number of the most significant forest machines used so far in forest harvesting. Also, the ways and activities are described by which »Hrvatske šume« d.o.o., in cooperation with the Faculty of Forestry, University of Zagreb, influence the trend of machine and technology development, as original solutions for meeting particularly demanding conditions of natural forest management.In the Republic of Croatia, the state owns 75% of the total area of forests and forest land, i.e. 2,018,987 ha are managed by »Hrvatske šume« d.o.o. »Hrvatske šume« d.o.o. carry out more than 50% of forest management activities by their own production forces and means. Therefore, the development of machines and technologies is a very significant precondition for improving business efficiency in severe terrain conditions, characterised by specific management methods. Four main criteria of suitability requirements, i.e. suitability of technical-technological solutions, can be singled out: Environmental suitability, Efficiency, Safety, Ergonomic suitability.These criteria have partly been established in line with modern international standards, applicable to conditions in the Republic of Croatia and partly by specific features of management conditions. The influence of »Hrvatske šume« on meeting the above requirements, and direct participation of »Hrvatske šume« in the development of technical-technological solutions suitable for certain conditions, have been shown on examples of development of two types of skidders and tractor assemblies for lowland forest thinning. Efforts are made to meet these requirements through tasks of the scientific-research work projects and in cooperation with the Faculty of Forestry, University of Zagreb, as well as by placing demands on and in cooperation with domestic manufacturers of machines and equipment.
Survival and growth of 31 Populus clones in South Carolina
About this Resource: Populus species and hybrids have many practical applications, but clonal performance is relatively undocumented in the southeastern United States outside of the Mississippi River alluvial floodplain. In spring 2001, 31 Populus clones were planted on two sites in South Carolina, USA. The sandy, upland site received irrigation and fertilization throughout the growing season, while the bottomland site received granular fertilizer yearly and irrigation in the first two years only. Over three growing seasons, tree survival and growth differed significantly among clones at both sites. Hybrid clones I45/51, Eridano, and NM6 had very high survival at both sites, while pure eastern cottonwood (P. deltoides) clones consistently had the lowest survival. Nearly all mortality occurred during the first year. The P. deltoides clone WV416 grew well at both sites, P. deltoides clones S13C20 and Kentucky 8 grew well at the bottomland site, and hybrids 184-411 and 52-225 grew well at the upland site. Based on both survival and growth, clones 311-93, S7C15, 184-411, and WV416 may warrant additional testing in the upper coastal plain region of the southeastern US. Kentucky 8 and S13C20 had excellent growth rates, but initial survival was low. However, this was likely due to planting stock quality. We emphasize this is preliminary information, and that clones should be followed through an entire rotation before large-scale deployment.
Three new species of Ceralocyna Viana, 1971 from Mexico and Ecuador (Cerambycidae: Cerambycinae, Trachyderini, Ancylocerina)
About this Resource: Three new species are described herein, one from coastal lowland deciduous forests of western M exico (Jalisco), one from coastal lowland deciduous scrub in western Ecuador (Manabi), and one from upper Amazonian Ecuador (Napo).
TOASTED FORESTS - EVERGREEN RAIN FORESTS OF TROPICAL ASIA UNDER DROUGHT STRESS
About this Resource: This paper has been written to make an enormous threat known to the public. We all know about the forest fires that raged in Indonesia and parts of Malaysia in 1997, and about the noxious haze covering the whole region, but only a few experts are aware of the threat of extinction of the last rain forest areas in Southeast Asia. As this paper will show, droughts have always been a part of these ecosystems, which normally receive plenty of rain. Mild droughts can be regarded as slight or medium disturbances, which can even have a stimulating effect according to the Intermediate Disturbance Hypothesis. However, severe droughts and fires have a destructive effect, which will only be overcome in successional stages. Logging and forest fragmentation reduce the ability of forests to overcome severe droughts. Forest fires rage in selectively logged forests, whereas they are extremely rare in undisturbed rain forests. Forest regeneration in fragmented forests is disturbed, so that we have to expect a total degradation of even effectively protected forest areas. Due to drought and fire, the remnant rain forest areas are being roasted like slices of toast . New research is also revealing that rain forests under drought stress consume more oxygen than they produce. The "green lung" and carbon sink are thus out of function. Furthermore, severe ENSO-(El Niño/Southern Oscillation)-droughts have been increasing in recent years. The consequences both for development of the region and for the whole atmosphere are imminent. Forest fires during ENSO droughts have caused extensive damage to forests and plantations, and noxious haze clouds in the whole region. Awareness about ENSO and droughts exists and is growing within the local population. Strict regulations, drought and fire alerts, and law enforcement can reduce at least the effects of drought. A logging ban, also including selective logging, may have to be considered. While this paper covers the whole of tropical Asia, it focuses on Sumatra, Borneo and the Malay Peninsula, which are the main evergreen rain forest areas. Other areas in the region have either seasonal vegetation, which is more drought adapted, or only small pockets of evergreen rain forest depending on local rain exposure - or the lowland forests have disappeared. The paper concentrates on Western Indonesia, Malaysia and the very south of Thailand.
TREE COMMUNITY OF AN ALLUVIAL LOWLAND FOREST IN THE MUNICIPALITY OF CAMPOS DOS GOYTACAZES, RJ, BRAZIL
About this Resource: This study evaluated tree community structure and floristic composition of an alluvial lowland forest at Campos dosGoytacazes, north of Rio de Janeiro State, Brazil. Tree community (DBH 3.2 cm) was sampled using the Point Centered-Quarter(84 points, 336 trees). 105 species of 35 families were found. The richest families were Leguminosae (18 species), Euphorbiaceae (7),Lauraceae (6) and Rubiaceae (6). The values of basal area (17.3 m2.ha-1) and Shannon s species diversity (H = 4.02 nats.ind-1) weresimilar to others secondary forests in the region. When compared to other forest at the region, the Bom Jesus forest showed strongerfloristic relationships with semideciduous forests (Tabuleiro forests), especially those under the same climate and disturbanceconditions. Considering the extensively fragmented landscape and the ecological importance of this remnant for the maintenance of thetree species diversity in this region, this forest renmant should be among the priorities for conservation and management programs.
Fine root dynamics for forests on contrasting soils in the colombian Amazon
About this Resource: It has been hypothesized that in a gradient of increase of soil resources carbon allocated to belowground production (fine roots) decreases. To evaluate this hypothesis, we measured the mass and production of fine roots (<2 mm) by two methods: 1) ingrowth cores and, 2) sequential soil coring, during 2.2 years in two lowland forests with different soils in the colombian Amazon. Differences of soil resources were determined by the type and physical and chemical properties of soil: a forest on loamy soil (Ultisol) at the Amacayacu National Natural Park and, the other on white sands (Spodosol) at the Zafire Biological Station, located in the Forest Reservation of the Calderón River. We found that mass and production of fine roots was significantly different between soil depths (0–10 and 10–20 cm) and also between forests. White-sand forest allocated more carbon to fine roots than the clayey forest; the production in white-sand forest was twice (2.98 and 3.33 Mg C ha<sup>−1</sup> year<sup>−1</sup>, method 1 and 2, respectively) as much as in clayey forest (1.51 and 1.36–1.03 Mg C ha<sup>−1</sup> year<sup>−1</sup>, method 1 and 2, respectively); similarly, the average of fine root mass was higher in the white-sand forest (10.94 Mg C ha<sup>−1</sup>) than in the forest on clay soils (3.04–3.64 Mg C ha<sup>−1</sup>). The mass of fine roots also showed a temporal variation related to rainfall, such that production of fine roots decreased substantially in the dry period of the year 2005. Our results suggest that soil resources play an important role in patterns of carbon allocation in these forests; carbon allocated to above-and belowground organs is different between forest types, in such a way that a trade-off above/belowground seems to exist; as a result, it is probable that there are not differences in total net primary productivity between these two forests: does belowground offset lower aboveground production in poorer soils?
Mapping landscape scale variations of forest structure, biomass, and productivity in Amazonia
About this Resource: Landscape and environmental variables such as topography, geomorphology, soil types, and climate are important factors affecting forest composition, structure, productivity, and biomass. Here, we combine a network of forest inventories with recently developed global data products from satellite observations in modeling the potential distributions of forest structure and productivity in Amazonia and examine how geomorphology, soil, and precipitation control these distributions. We use the RAINFOR network of forest plots distributed in lowland forests across Amazonia, and satellite observations of tree cover, leaf area index, phenology, moisture, and topographical variations. A maximum entropy estimation (Maxent) model is employed to predict the spatial distribution of several key forest structure parameters: basal area, fraction of large trees, fraction of palms, wood density, productivity, and above-ground biomass at 5 km spatial resolution. A series of statistical tests at selected thresholds as well as across all thresholds and jackknife analysis are used to examine the accuracy of distribution maps and the relative contributions of environmental variables. The final maps were interpreted using soil, precipitation, and geomorphological features of Amazonia and it was found that the length of dry season played a key role in impacting the distribution of all forest variables except the wood density. Soil type had a significant impact on the wood productivity. Most high productivity forests were distributed either on less infertile soils of western Amazonia and Andean foothills, on crystalline shields, and younger alluvial deposits. Areas of low elevation and high density of small rivers of Central Amazonia showed distinct features, hosting mainly forests with low productivity and smaller trees.
The arid and dry plant formations of south America and their floristic connections: new data, new interpretation?
About this Resource: In this study we aimed at testing two hypothesis about the biogeography of South America: (1) the existence of a marked discontinuity in the Andes of central Peru that separates the floras of northern and southern South America and (2) the occurrence of a more or less continuous semi-deciduous forest in South America during the Pleistocene. We conducted a search for different sources of published information on the flora (inventories) of 19 dry regions in South America as well as one region in Central America and another in North America. In order to analyze the data, we employed ordination and classification techniques, which give a more objective picture of the phytogeographical relationships. Additionally, we evaluated similarity scores between the regions. We found 1,421 woody and herbaceous genera for the 21 regions. These regions form two groups: one mostly in northern South America and the other one restricted to the southern half of the hemisphere. Within the latter, further subdivisions are discernible. Almost all the northern group is made up of tall, deciduous and semi-deciduous forest types. The southern group regions mainly range from very dry forests to desert scrub. Our results support the existence of a floristic discontinuity in relation to the drier flora of the Andes. The southern flora (from southern Peru to northern Argentina and Chile) constitutes a floristic group quite different from that of northern South America. The Chaco region, although more floristically related to the southern group, seems to constitute the connecting link between these northern and southern floras. Within the flora of southern South America, the coastal desert seems to be the connection between hot and cold semi-deserts. Our data also support the hypothesis of the existence of pleistocenic lowland forests in most parts of South America which, however, probably extended up to Mexico.
Multivariate characterisation of environmental conditions for reindeer husbandry in Sweden
About this Resource: Pastoralism using semi-domesticated reindeer (Rangifer t. tarandus) is a traditional livelihood in northern Fennoscandia. The area used for reindeer herding in Sweden covers as much as half of the country’s area. Variation in the productivity of reindeer husbandry is clearly affected by many biotic and abiotic factors. The aim of this investigation was to identify factor combinations which describe the spatial variation in conditions that plausibly determine productivity in reindeer herding. Initially, 37 variables representing geographical location, climate, weather episodes related to ice crust formation and insect harassment, topography, vegetation, forage abundance and qualities, and fragmentation of the ranges were derived, using prior ecological knowledge and spatially explicit data. The variables were mapped in a raster of 1958 squares of 100 km2 each, covering the entire Swedish reindeer herding area. Reductions of variables were performed with multivariate analyses in steps, ultimately retaining 15 variables. The first five principal components (PCs) of these variables explained 84% of the total variation. The first component, related to major western mountain/eastern lowland gradients, already accounts for 49% of the variation. The following components explained variation ranging from 10% to 5.4%, and revealed spatial patterns in summer versus winter forage, climatic conditions and ice crust formation, abundance of forests and winter forage, and northward slopes together with valuable forest areas, respectively. A tentative zone division of the Swedish reindeer herding area into seven zones was made, based upon cluster analysis and spatial distribution of component scores. Extending this approach and method seems useful also in the understanding and management of other natural resources and national parks, especially with an ongoing global climate change perspective. Abstract in Swedish / Sammandrag: Multivariat karakterisering av grundförutsättningar för renskötsel i Sverige. Den areal som nyttjas av renskötseln i Sverige täcker ungefär halva landets yta. Renens produktivitet varierar inom området beroende på många biotiska och abiotiska faktorer. Målet var att identifiera kombinationer av underliggande faktorer som kan orsaka den varierade produktiviteten inom renskötseln. Baserat på tidigare kunskap och spatiella data valdes 37 variabler som beskriver relevant variation i geografisk belägenhet, klimat, väderhändelser relaterade till skareförekomst och insektsstörningar, topografi, vegetation, betesmängd och -kvalitet, samt fragmentering av betesland. Värdena i dessa variabler beräknades för 1958 kvadrater à 100 km2, som tillsammans täckte hela renskötselområdet. Materialet analyserades med en stegvis principalkomponentanalys och klusteranalys, varvid antalet variabler reducerades till 15. De fem första principalkomponenterna, baserade på 15 variabler, förklarade tillsammans 84% av den samlade variationen, varav den första principalkomponenten ensam förklarade 49% och de efterföljande fyra komponenterna stod för vardera mellan 10 och 5,4%. Tolkningen av den första komponenten tyder på att den främst förklarade väntade öst-västliga gradienter i topografiska och klimatologiska förhållanden. De efterföljande principalkomponenterna förklarade den samlade variationen i sommar- kontra vinterbete, klimatförutsättningar och skareförekomst, skog och vinterbetesfördelning, resp. nordsluttningar i kombination med värdefull skogsmark, utöver de gradienter som isolerats i första komponenten. Baserat på den spatiella utbredningen av principalkomponentvärden föreslår vi en uppdelning av renskötselområdet i sju zoner med avseende på faktorer av betydelse för renskötseln. Denna ansats och metodik förefaller vara väl lämpad för förståelse och förvaltning av naturresurser och skyddsvärda områden generellt, speciellt i ett globalt föränderligt klimat.
Litter dynamics and phenology of Melaleuca quinquenervia in south Florida
About this Resource: We monitored litterfall biomass at six different sites of melaleuca (Melaleuca quinquenervia (Cav.) S.T. Blake) forested wetlands in South Florida from July 1997 to June 1999. Annual litterfall of melaleuca varied between sites from 6.5 to 9.9 t dry wt ha(-1) yr(1) over the two-year period. Litterfall was significantly higher (p < 0.0001) in scasonally flooded habitats (9.3 t ha(-1) yr(1)) than in non-flooded (7.5 t ha(-1) yr(1)) and permanently flooded habitats (8.0 t ha(-1) yr(1)). Leaf fall was the major component forming 70% of the total litter, woody material 16%, and reproductive material 11%. Phenology of flowering and leaf flush was investigated by examination of the timing and duration of the fall of different plant parts in the litter traps, coupled with monthly field observations during the two-year study. In both years, flowering began in October and November, with peak flowers production around December, and was essentially completed by February and March. New shoot growth began in mid winter after peak flowering, and extended into the spring. Very little new growth was observed in melaleuca forests during the summer months, from May to August, in South Florida. In contrast, the fall of leaves and small wood was recorded in every month of the year, but generally increased during the dry season with higher levels observed from February to April. Also, no seasonality was recorded in the fall of seed capsules, which apparently resulted from the continual self-thinning of small branches and twigs inside the forest stand. In planning management for perennial weeds, it is important to determine the period during its annual growth cycle when the plant is most susceptible to control measures. These phenological data suggest that the appropriate time for melaleuca control in South Florida might be during late winter and early spring, when the plant is most active.
Comparative analysis of the actual evapotranspiration of Flemish forest and cropland, using the soil water balance model WAVE
About this Resource: This paper focuses on the quantification of the green – vegetation related – water flux of forest stands in the temperate lowland of Flanders. The underlying reason of the research was to develop a methodology for assessing the impact of forests on the hydrologic cycle in comparison to agriculture. The tested approach for calculating the water use by forests was based on the application of the soil water balance model WAVE. The study involved the collection of data from 14 forest stands, the calibration and validation of the WAVE model, and the comparison of the water use (WU) components – transpiration, soil and interception evaporation – between forest and cropland. For model calibration purposes simulated and measured time series of soil water content at different soil depths, period March 2000–August 2001, were compared. A multiple-site validation was conducted as well. Actual tree transpiration calculated with sap flow measurements in three forest stands gave similar results for two of the three stands of pine (Pinus sylvestris L.), but WAVE overestimated the actual measured transpiration for a stand of poplar (Populus sp.). A useful approach to compare the WU components of forest versus cropland is scenario analysis based on the validated WAVE model. The statistical Profile Analysis method was implemented to explore and analyse the simulated WU time series. With an average annual rainfall of 819 mm, the results reveal that forests in Flanders consume more water than agricultural crops. A 30 years average of 491 mm for 10 forests stands versus 398 mm for 10 cropped agricultural fields was derived. The WU components, on yearly basis, also differ between the two land use types (transpiration: 315 mm for forest and 261 mm for agricultural land use; soil evaporation: 47 mm and 131 mm, for forest and cropland, respectively). Forest canopy interception evaporation was estimated at 126 mm, while it was negligible for cropland.
Forest colonization of Puget Lowland Grasslands at Fort Lewis, Washington
About this Resource: As a result of fire exclusion since the mid-19th century, Douglas-fir has been invading the grasslands of the southern Puget Lowland, Washington, converting them to colonization forests. We studied a chronosequence of these forests, including some that received periodic commercial thinnings, at Fort Lewis Military Reservation to elucidate successional patterns and changes in ecosystem properties associated with tree invasion. In unmanaged colonization forests (ages 27-120 yr), overstory cover and tree density remained constant after 27 yr, while basal area increased. Shrub cover increased with age and, after an initial decrease compared to grasslands, ground cover also increased. Shrub species richness increased over time, while ground-layer richness was much less than in grasslands, and there was a rapid shift from grassland to forest floras. Dead wood (snags and logs) accumulated gradually. The only change in soil properties was lower A-horizon nitrogen. In managed colonization forests (ages 55-91 yr), tree density, overstory cover, and total log length decreased over time, but shrub cover and A-horizon cation-exchange capacity, carbon, and nitrogen increased over time. Although structural and floristic conversion of grassland to forest requires <30 yr, soil changes are much more gradual, such that the soils underlying colonization forests up to 400 yr old are still classified as grassland soils. Higher tree densities in colonization forests compared to the pre-settlement forests of Fort Lewis mean an increased risk of crown fires during droughts. Even with active management, colonization forests will require many decades to provide northern spotted owl habitat because they lack shade-tolerant conifers and large live trees, snags, and logs
Distribution, habitat selection and facial morphology of setts of badgers (Meles meles Linnaeus, 1758) in the region of Erdospusztak (Eastern Hungary)
About this Resource: The badger’s population density has shown a general increase in Hungary since the 1980s. The data show that the species has occurred in wide range in areas (like lowland areas) which are not known as traditional distribution area of badgers. The traditional habitats of badgers in Hungary are the hilly deciduous forests. But in the lowland rea around Debrecen we recognized increasing distribution and population density of the species. In this study we show the present status of the species in the semi-natural and planted forests and deforested areas around Debrecen and the habitat selection and the morphology of inhabited setts of the badgers living in these forests in a sample area.We recorded data on general distribution by questionnaires sent to hunting companies. The population density and habitat selection of the ample area was measured by recording of locality of setts of badgers. We used the method of line transect and analysis of habitat type through satellite pictures and GPS coordinates. To have data on morphology of setts we recorded the number of entrances, the exposure, overing, macro- and microrelief, occurrence of latrines.Our data show that the badgers are widely distributed in this area and heir population density reached the density of the species traditional habitats (2,44 setts/hectare). The habitat selection shows a small preference (Ivlev-index = 30%) to the forested areas. This small preference to the forests shows that the covering of the habitat is not the single crucial factor of their habitat selection. The level of preference to the several forest types shows that the badgers of the sample areas prefer (Ivlev-index = 58 %) the planted pine forests (Pinus sylvestris). This result is similar to other research results made in other part of Hungary but out of accordance to the results of researches made in England.
Impacts of Falcataria moluccana Invasion on Decomposition in Hawaiian Lowland Wet Forests: The Importance of Stand-level Controls
About this Resource: Invasive species have the capacity to substantially alter soil processes, including rates of litter decomposition. Currently, the few remaining native-dominated lowland wet forests in Hawai'i are being invaded by Falcataria moluccana, a large, fast-growing, N₂-fixing tree. In this study, we sought to determine the extent to which Falcataria invasion alters decomposition in these lowland wet forests, and whether changes resulted from differences in litter substrate type, lava flow age and type, forest stand type and associated soil biota, or some combination of these factors. We measured decomposition rates and nitrogen (N) and phosphorus (P) dynamics of Metrosideros polymorpha and Falcataria leaf litter in native-dominated and Falcataria-invaded stands on 48- and 300-year-old a'a lava flows and a 213-year-old pāhoehoe flow in the Puna district of eastern Hawai'i. Despite significant differences in the initial quality of Metrosideros and Falcataria litter, in nearly all cases mass remaining of the two litter types did not differ within a given forest stand, whether native-dominated or invaded. Instead, stand type accounted for large differences in the decomposition of both litter types, and litter decomposed two to 10 times faster in Falcataria-invaded stands than it did in their native-dominated counterparts on each lava flow. Dynamics of N (that is, immobilization or release) during decomposition were affected by stand, litter, and lava flow type; P dynamics were affected by stand and flow type, but not litter type. Although not definitive proof of causality, the decay rates of both species were positively correlated to previously measured inputs of N mass and P mass via litterfall as well as availability of soil N and P, characteristics that all increased substantially with Falcataria invasion. Given the degree of change to a host of ecosystem processes, including decomposition, after invasion by Falcataria, these transformed forest ecosystems may best be viewed as fundamentally new and different, in both structure and function, from the native ecosystems they have replaced.
Liana infestation impacts tree growth in a lowland tropical moist forest
About this Resource: Stand-level estimates of the effect of lianas on tree growth in mature tropical forests are needed to evaluate the functional impact of lianas and their potential to affect the ability of tropical forests to sequester carbon, but these are currently lacking. Using data collected on tree growth rates, local growing conditions and liana competition in five permanent sampling plots in Amazonian Peru, we present the first such estimates of the effect of lianas on above-ground productivity of trees. By constructing a multi-level linear mixed effect model to predict individual tree diameter growth model using individual tree growth conditions, we were able to estimate stand-level above-ground biomass (AGB) increment in the absence of lianas. We show that lianas, mainly by competing above-ground with trees, reduce tree annual above-ground stand-level biomass by ~10%, equivalent to 0.51 Mg dry weight ha<sup>−1</sup> yr<sup>−1</sup> or 0.25 Mg C ha<sup>−1</sup> yr<sup>−1</sup>. AGB increment of lianas themselves was estimated to be 0.15 Mg dry weight ha<sup>−1</sup> yr<sup>−1</sup> or 0.07 Mg C ha<sup>−1</sup> yr<sup>−1</sup>, thus only compensating ~29% of the liana-induced reduction in stand-level AGB increment. Increasing liana pressure on tropical forests may therefore not only reduce their carbon storage capacity, by indirectly promoting tree species with low-density wood, but also their rate of carbon uptake, with potential consequences for the rate of increase in atmospheric carbon dioxide.
Birds surveyed in the harvested and unharvested areas of a reduced-impact logged forestry concession, located in the lowland subtropical humid forests of the Department of Santa Cruz, Bolivia.
About this Resource: As part of a larger study of reduced-impactlogging effects on bird community composition,we surveyed birds from December to Februaryduring the 2003-2004 wet-season within harvestedand unharvested blocks of the La Chonta forestryconcession, Department of Santa Cruz, Bolivia.The logged forest was harvested using reduced-impactlogging techniques between one and fouryears previously. During point count surveys, weidentified 5062 individual birds, belonging to 155species, and 33 families. We provide a list of birdspecies found within the harvested andunharvested blocks of the concession for thebenefit of other researchers assessing theresponses of Neotropical avifauna to disturbance,and to facilitate increased understanding of thediverse bird assemblages found within thelowland subtropical humid forests of Bolivia.
Cryptic diversity and deep divergence in an upper Amazonian leaflitter frog, Eleutherodactylus ockendeni
About this Resource: Abstract Background The forests of the upper Amazon basin harbour some of the world's highest anuran species richness, but to date we have only the sparsest understanding of the distribution of genetic diversity within and among species in this region. To quantify region-wide genealogical patterns and to test for the presence of deep intraspecific divergences that have been documented in some other neotropical anurans, we developed a molecular phylogeny of the wide-spread terrestrial leaflitter frog Eleutherodactylus ockendeni (Leptodactylidae) from 13 localities throughout its range in Ecuador using data from two mitochondrial genes (16S and cyt b; 1246 base pairs). We examined the relation between divergence of mtDNA and the nuclear genome, as sampled by five species-specific microsatellite loci, to evaluate indirectly whether lineages are reproductively isolated where they co-occur. Our extensive phylogeographic survey thus assesses the spatial distribution of E. ockendeni genetic diversity across eastern Ecuador. Results We identified three distinct and well-supported clades within the Ecuadorean range of E. ockendeni: an uplands clade spanning north to south, a northeastern and central lowlands clade, and a central and southeastern clade, which is basal. Clades are separated by 12% to 15% net corrected p-distance for cytochrome b, with comparatively low sequence divergence within clades. Clades marginally overlap in some geographic areas (e.g., Napo River basin) but are reproductively isolated, evidenced by diagnostic differences in microsatellite PCR amplification profiles or DNA repeat number and coalescent analyses (in MDIV) best modelled without migration. Using Bayesian (BEAST) and net phylogenetic estimates, the Southeastern Clade diverged from the Upland/Lowland clades in the mid-Miocene or late Oligocene. Lowland and Upland clades speciated more recently, in the early or late Miocene. Conclusion Our findings uncover previously unsuspected cryptic species diversity within the common leaflitter frog E. ockendeni, with at least three different species in Ecuador. While these clades are clearly geographically circumscribed, they do not coincide with any existing landscape barriers. Divergences are ancient, from the Miocene, before the most dramatic mountain building in the Ecuadorean Andes. Therefore, this diversity is not a product of Pleistocene refuges. Our research coupled with other studies suggests that species richness in the upper Amazon is drastically underestimated by current inventories based on morphospecies.
Comparison of two approaches to soil strength classifications
About this Resource: The paper presents a comparison of two approaches to describing vehicle trafficability of cohesive soils. The first approach is based on soil consistency and Atterberg index indicators. The second approach is based on the cone penetrometer measurement and on the vane shear test, as well as on the EcoWood classification of soil strength.The research was carried out in the lowland region of pedunculate oak forests in the Sava River basin. Three cut-blocks of different moisture and forest soil strength were selected, in which timber was extracted by a forwarder. Measurements and sampling were carried outon undisturbed soil. Research results have shown that both approaches to describing vehicle trafficability of cohesive soils describe the soil strength of forest wilderness in a similar way and provide a good basis for developing a trafficability evaluation system, as a future task of forest engineering. The soil cone index and shear strength values calculated in this research do not concur withthe classes of EcoWood soil strength classification and indicate that the limits and ranges of these parameters are questionable. The problem of defining the threshold values of soil strength parameters covered by this research will be the subject of future investigations.
Thirty thousand years of vegetation development and climate change in Angola (Ocean Drilling Program Site 1078)
About this Resource: ODP Site 1078 situated under the coast of Angola provides the first record of the vegetation history for Angola. The upper 11 m of the core covers the past 30 thousand years, which has been analysed palynologically in decadal to centennial resolution. Alkenone sea surface temperature estimates were analysed in centennial resolution. We studied sea surface temperatures and vegetation development during full glacial, deglacial, and interglacial conditions. During the glacial the vegetation in Angola was very open consisting of grass and heath lands, deserts and semi-deserts, which suggests a cool and dry climate. A change to warmer and more humid conditions is indicated by forest expansion starting in step with the earliest temperature rise in Antarctica, 22 thousand years ago. We infer that around the period of Heinrich Event 1, a northward excursion of the Angola Benguela Front and the Congo Air Boundary resulted in cool sea surface temperatures but rain forest remained present in the northern lowlands of Angola. Rain forest and dry forest area increase 15 thousand years ago. During the Holocene, dry forests and Miombo woodlands expanded. Also in Angola globally recognised climate changes at 8 thousand and 4 thousand years ago had an impact on the vegetation. During the past 2 thousand years, savannah vegetation became dominant.
Stocks of organic carbon in Estonian soils
About this Resource: The soil organic carbon (SOC) stocks (Mg ha–1) ofautomorphic mineral (9 soil groups), hydromorphic mineral (7), and lowland organic soils (4) are given for the soil cover or solum layer as a whole and also for its epipedon (topsoil) layer. The SOC stocks for forest, arable lands, and grasslands and for the entire Estonian soil cover were calculated on the basis of the mean SOC stock and distribution area of the respective soil type. In the Estonian soil cover (42 400 km2), a total of 593.8 ± 36.9 Tg of SOC is retained, with 64.9% (385.3 ± 27.5 Tg) in the epipedon layer (O, H, and A horizons) and 35.1% in the subsoil (B and E horizons). The pedo-ecological regularities of SOC retention in soils are analysed against the background of the Estonian soil ordination net.
The Use of Principal Component Analysis in Studying Physical, Chemical and Biological Soil Properties in Southern Caspian Forests (North of Iran)
About this Resource: <p>This research was conducted in Khanikan forests located in lowland of Mazandaran province (North of Iran). Eighteen profiles were dug and several chemical, physical and biological soil properties were investigated. The soil properties evaluated were soil pH, bulk density, saturation moisture content, electrical conductivity, organic carbon, total nitrogen, cation exchangeable capacity, available phosphorous, soil texture, calcium carbonate content, number and biomass of earthworms, litter carbon and litter nitrogen. Principal Component Analysis (PCA) was used to identify the variation of soil properties. PCA, a technique which reduces the dimensionality of multivariate data by removing Interco relations among variables, has a number of useful applications in forest researches. The results showed significant relationships between some soil factors with PC<sub>1</sub> and PC<sub>2</sub> axes, also, among different soil factors, the distribution of forest types was most strongly controlled with some soil characteristics such as acidity, bulk density, texture, phosphorous, organic carbon, total nitrogen and cation exchangeable capacity.</p>
How do soil fauna and soil microbiota respond to beech forest growth?
About this Resource: The dynamics and performance of soil biota during forest rotation were studied in monoculture beech stands forming a chronosequence of four different age-classes (30, 62, 111, 153 yr). Biomass was monitored in major groups of microflora, microfauna, mesofauna, and macrofauna. Resource availability (litter layer, soil organic mater), biomass of the two dominant decomposer groups (microflora, earthworms) as well as the biomass of mesofauna and microfauna were found to remain quite stable during forest succession. Nevertheless, the marked increase of the biomasses of primary decomposers (fungi, saprophagous macroinvertebrates) in the 62-year-old stand, followed by an increase of the biomasses of macropredators in the 111-year-old stand, indicate substantial changes of several components of edaphic communities during forest development. However, constant values of soil respiration suggest that the overall performance of the soil food web does not change during beech forest succession. Thus, the decomposer system of lowland managed beech forests on calcareous soils seems to be very stable over time. We suggest that earthworm activity might have masked impacts of forest development on other soil biota and led to an astounding stability of decomposer assemblages during beech forest rotation [Current Zoology 55 (4): 272–278, 2009].
Scope and constraints for tree planting in the irrigated landscapes of the Aral Sea Basin: case studies in Khorezm Region, Uzbekistan
About this Resource: A wealth of research papers, reports, and newsprint demonstrate the wide international interest in the ecological deterioration in the Aral Sea Basin in Central Asia (CA). The demise of the Aral Sea is a symptom that results from intensive agricultural activities aiming at maximizing agricultural production while neglecting environmental sustainability, as exemplified by the land use patterns also prevalent in the Republic of Uzbekistan, one of the five newly established states in CA. The environmental degradation is acute and continues, since various factors conducive to it have not been eradicated. This discussion paper deals with the potential role of forestry-based production systems and in their contribution to counterbalancing the ecological landscape demise in the region. This discussion paper starts with a brief overview of environmental conditions in CA, followed by a discussion of forestry and agroforestry in CA's irrigated semi-arid and arid landscapes. The paper focuses on Uzbekistan, and more specifically the province (viloyat) of Khorezm, which is located at the southern rim of the Aral Sea Basin and serves as an example for the Middle Asia lowlands. The results of surveys on farmers' perception of forest and tree products, as well as the outcomes of field measurements of the productivity of tree stands and agroforestry systems, regional forestry governance, and the market situation for timber products are discussed. Following data mining of secondary sources, field, market and household surveys, combined with in-depth analyses using remote sensing techniques, the paper re-assesses the tree resources of Uzbekistan and concludes that the present use and management of trees and forests is inadequate. Well-designed multi-species windbreaks are absent (single-tree rows of mulberry comprise about 50% of the present tree strips), only 70% of the tree windbreaks were oriented in the North-South and North/West-South/East directions, from which the highest wind speeds (>3m s-1) are generally measured, and the majority of the investigated tree strips did not satisfy the minimal height of 5 m. More than half (55%) of the strips did not stretch over the entire length of the related field. However, other structural criteria such as stand porosity and width had acceptable values. In the hedgerow systems monitored tree planting schemes varied considerably but on average were much lower compared to the recommended planting schemes by forestry administrations as the perennial crops were of more importance to the farmers. The farmers planted mostly fruit trees to increase income and improve their food basket, but none of the ca. 100 interviewed was ecologically motivated. However, the total land area of the various surveyed agroforestry systems on both private and rented land was the largest where tree age did not exceed 12 years, thus indicating the interest of tree planting. The surveys results are followed by a review of forestry policies in Uzbekistan. The paper concludes with a set of recommendations concerning managerial and research needs for forest and agroforestry systems in irrigated drylands of CA, and outlines the opportunities and need for external support at both the country and sub-regional level. Despite the role trees could potentially play, the lack of training of the farming population, reduced capacities of the forestry administration and their staff as well as shortcomings in the forest legislation have resulted in many underperforming "goodwill" efforts. Due to the complexity of the social, economical and physical components and their interdependencies, this paper calls for integrated knowledge generation, concerted action and for administrative and research support. The crisis in the Aral Sea Basin has a strong global dimension, which calls for targeted support at both country and international donor community levels.