Softwood Forest Research Articles

EARLY OLIGOCENE RIPARIAN AND SWAMP FORESTS WITH A MASS OCCURRENCE OF ZINGIBEROIDEOPHYLLUM (EXTINCT ZINGIBERALES) FROM SAXONY, CENTRAL GERMANY

Abstract A remarkable fossil plant assemblage from the lowermost Oligocene Haselbach horizon (Grobers Member, Bohlen Formation) was excavated at the Vereinigtes Schleenhain opencast mine (northwestern Saxony, Germany) and is described herein. The lower unit of the Haselbach horizon represents abandoned channel deposits that contain masses of Zingiberoideophyllum liblarense leaves. Species identification of the leaves is based on morphological characters and micromorphological features of the cuticle. Other plant organs of the previously described whole plant Spirematospermum wetzleri-Zingiberoideophyllum liblarense, such as fruits, seeds, rhizomes, and rootlets, were also observed on associated bedding planes, which supports this whole-plant reconstruction. The other megafossil remains in this taphocoenosis, mostly leaves, are identified taxonomically and interpreted as being derived from a mixed softwood and hardwood riparian forest of Acer haselbachense, Apocynophyllum neriifolium, Carpinus grandis, Eng...

Investigation of the Applicability of Multi-Operational Logging Machines in Hardwood Stands

Abstract - As a result of new developments in technology, harvesters may no longer be confined to softwood forests only. Several studies carried out in black locust, Turkey oak and beech stands have justified the use of these machines in hardwood stands. Evaluating the results of the cost and time analyses we concluded that harvesters are more efficient in several cases compared to traditional felling with chainsaws.

Floodplain willows in fragmented river landscapes: Understanding spatio-temporal genetic patterns as a basis for restoration plantings

In Central Europe, floodplain fragmentation by dykes and river regulation by dams has led to a fundamental loss of riparian softwood forests and dramatically restricted natural regeneration of the Salicaceae species involved. As a consequence, reforestation is one of the widely-used measures to maintain this valuable vegetation type. Knowledge about the genetic population structure of existing stands of willows and poplars is necessary to preserve their genetic potential in the long term. In this study, we investigated clonal and genetic diversity patterns of Salix viminalis for 23 stands, taking into account young and old age classes and locations in front of the dykes in the active floodplain and behind the dykes in the inactive floodplain along the Elbe River, Germany. Microsatellites were used to assess effects of stand and floodplain fragmentation and to evaluate the extent of clonal structures. We detected considerable numbers of multi-ramet-clones almost exclusively in the active floodplain with old stands exhibiting the largest number of these clones. Individual clones mostly covered distances of less than 10m, but single long distance dispersal events of vegetative propagules were also detected. Genetic diversity patterns revealed one continuous population although a certain small-scale spatial genetic structure was identified. Our study suggests that riparian softwood forest species have efficient dispersal strategies which allow the population to survive altered floodplain conditions from a genetic point of view. Management advice is given for selecting genetically suitable planting material for restoration purposes.

Managing floodplain‐forest restoration in European river landscapes combining ecological and flood‐protection issues

Throughout Europe the demands for improved flood protection on the one hand and the requirements to maintain and enhance floodplain forests on the other are perceived as conflicting goals in river-basin management, revealing the urgent need for strategies to combine both issues. We developed an interdisciplinary approach for floodplain-forest restoration identifying sites suitable for reforestations from both an ecological and hydraulic point of view. In the ecological module, habitat-distribution models are developed providing information on ecologically suitable sites. In the hydraulic module, a two-dimensional hydrodynamic-numerical model (2D-HN model) delivers the requested hydraulic information. The output of the two models is intersected. Subsequently, in an iterative procedure, the potential of plantings without exceeding critical water levels can be identified by hydraulic evaluation using the 2D-HN-model. The approach is exemplified using two reforestation scenarios at the Elbe River, Germany, showing considerable potential for softwood forest establishment without negative hydraulic effects. The approach reported here provides a solution for a severe conflict in river-basin management that hampers the reestablishment of the strongly threatened floodplain forests in Europe. Alternative measures to enhance floodplain-forest regeneration feasible under certain preconditions are discussed in the context of the current state of European large rivers.

Benchmark carbon stocks from old-growth forests in northern New England, USA

Forests world-wide are recognized as important components of the global carbon cycle. Carbon sequestration has become a recognized forest management objective, but the full carbon storage potential of forests is not well understood. The premise of this study is that old-growth forests can be expected to provide a reasonable estimate of the upper limits of carbon storage for similar forest types in comparable site conditions. We sampled old-growth stands in Maine, Vermont, and New Hampshire to establish benchmark values for carbon storage in the forests of northern New England. Our specific objectives were: (1) develop estimates of carbon stocks in key live and dead biomass carbon pools of hardwood and softwood forests in northern New England, (2) compare these values to other estimates of carbon stocks in old-growth forests, and (3) compare data collected from mature second-growth forests to the old-growth benchmark values. Twelve sites in Vermont, New Hampshire, and Maine were sampled to estimate total carbon stocks in aboveground live and dead biomass, down dead wood, forest floor, and soil to 20 cm. Total carbon stocks averaged 216 t/ha for northern hardwoods and 267 t/ha in softwood sites, with 116 and 125 t/ha in the aboveground live tree biomass for hardwoods and softwoods, respectively. Our results showed old-growth softwood averaged about 25% more carbon than old-growth hardwood, primarily due to the higher carbon amounts in the thick forest floors characteristic of old-growth softwood. Old-growth hardwoods supported live biomass carbon stocks similar to those in mature hardwood stands (about 80–120 years old), although forest floor stocks in old-growth were about twice as high (a non-significant difference). Overall carbon stocks in mature second-growth hardwoods were 89% of those in old-growth stands; this difference was not statistically significant. Additional work is needed in mature second-growth softwoods; data were not available for comparison to the benchmarks.

Land management strategies for the long-term persistence of boreal woodland caribou in central Saskatchewan

We investigated landscape changes and their potential effects on woodland caribou-boreal ecotype (Rangifer tarandus caribou) within a portion of the Smoothstone-Wapaweka Woodland Caribou Management Unit (SW-WCMU). The SW-WCMU is one of eight areas delineated by the Province of Saskatchewan for potential recovery planning efforts for boreal caribou, and is one of four management units located on the Boreal Plain Ecozone. The Prince Albert Greater Ecosystem (PAGE) study area was selected within the SW-WCMU for intensive study from 2004 - 2008. Studies focused on quantifying a suite of landscape and population parameters. This paper presents a summary of study results to date and recommends land management strategies intended to contribute to the long-term viability of boreal caribou in the central boreal plain ecoregion of Saskatchewan. The PAGE study area has undergone structural changes from an area that historically presented a lesser amount but well connected mature coniferous forest, to a currently larger amount of mature coniferous stands fragmented by a highly developed network of roads and trails. Movement data pointed to highly clustered use of the landscape by small groups of caribou and smaller home ranges when compared to 15 years ago. Calving sites were located within each individual home range in treed peatland and distant from hardwood/mixedwood forest stands, roads and trails access. Adult annual survival rates were low, averaging 73% over the course of the study. In order to ensure a self-sustaining population level, study results clearly point to the need for landscape restoration to reduce the level of anthropogenic disturbances in some key parts of the study area. Key strategies include retention of mature softwood forest interior proximate to local areas of caribou activity, protection of calving habitat, improving structural connectivity, planning disturbances (forest harvesting, fire salvage, resource exploration, access development) in ways to minimize the anthropogenic footprint, and recovery action planning integrated with other land-use planning initiatives.

Brown rot fungal early stage decay mechanism as a biological pretreatment for softwood biomass in biofuel production

A current barrier to the large-scale production of lignocellulosic biofuels is the cost associated with the energy and chemical inputs required for feedstock pretreatment and hydrolysis. The use of controlled partial biological degradation to replace elements of the current pretreatment technologies would offer tangible energy and cost benefits to the whole biofuel process. It has been known for some time from studies of wood decay that, in the early stages of growth in wood, brown rot fungi utilise a mechanism that causes rapid and extensive depolymerisation of the carbohydrate polymers of the wood cell wall. The brown rot hyphae act as delivery vectors to the plant cell wall for what is thought to be a combination of a localised acid pretreatment and a hydroxyl radical based depolymerisation of the cell wall carbohydrate polymers. It is this quality that we have exploited in the present work to enhance the saccharification potential of softwood forest residues for biofuel production. Here we show that after restricted exposure of pine sapwood to brown rot fungi, glucose yields following enzymatic saccharification are significantly increased. Our results demonstrate the potential of using brown rot fungi as a biological pretreatment for biofuel production. © 2010 Elsevier Ltd.

Carbon stocks of soil and vegetation on Danubian floodplains

AbstractRiparian forests are assumed to play a crucial role in the global carbon cycle. However, little data are available on C stocks of floodplains in comparison to other terrestrial ecosystems. In this study, we quantified the C stocks of aboveground biomass and soils of riparian vegetation types at 76 sampling sites in the Donau‐Auen National Park in Austria. Based on our results and a remotely sensed vegetation map, we estimated total C stocks. Carbon stocks in soils (up to 354 t ha–1 within 1 m below surface) were huge compared to other terrestrial ecosystems. As expected, soils of different vegetation types showed different texture with a higher percentage of sandy soils at the softwood sites, while loamy soils prevailed at hardwood sites. Total C stocks of vegetation types were significantly different, but reflect differences in woody plant biomass rather than in soil C stocks. Mature hardwood and cottonwood forests proved to have significantly higher total C stocks (474 and 403 t ha–1, respectively) than young reforestations (217 t ha–1) and meadows (212 t ha–1). The C pools of softwood forests (356 t ha–1) ranged between those of hardwood/cottonwood forests and of reforestations/meadows. Our study proves the relevance of floodplains as possible C sinks, which should be increasingly taken into account for river management. Furthermore, we conclude that plant‐species distribution does not indicate the conditions of sedimentation and soil C sequestration over the time span of interest for the development of soil C stocks.

Herb layer production in the willow stands on the Danubian soft-wood floodplain forest sites

Herb layer production in the willow stands on the Danubian soft-wood floodplain forest sites

Short-distance gene flow in Populus nigra L. accounts for small-scale spatial genetic structures: implications for in situ conservation measures

The European black poplar (Populus nigra L.) is a major species of riparian softwood forests. Due to human influences, it is one of the most threatened tree species in Europe. For restoration purposes, remaining stands may act as source populations. We analysed a natural population of P. nigra for genetic diversity and spatial genetic structure using seven microsatellite markers. For the first time, paternity analysis of seedlings as well as juveniles from a restricted area of natural regeneration was used to quantify pollen- and seed-mediated gene flow, respectively. In both cases, cultivated P. x canadensis trees in vicinity could act as potential parents. Spatial genetic patterns of the adult tree population suggest small-scale isolation by distance due to short-distance gene flow, the major part of which (i.e. 70%) takes place within distances of less than 1 km. This helps to explain the reduced diversity in the juveniles. It has implications for the spatial management of natural regeneration areas within in situ conservation measures.

The Second Industrial Revolution and the Staples Frontier in Canada: Rethinking Knowledge And History

In the late nineteenth century and the early twentieth century the exploitation of Canada's softwood forests was transformed by the new technologies of the second Industrial Revolution. This can be understood in terms of Innis's staple thesis as the exploitation of natural resources on a margin for and using the technology of a more advanced Euro-American centre. The sociology of knowledge also provides a framework for analysis as old and new bodies of technical knowledge were possessed by and altered the relationships among different social groups. Changes were experienced both in the woods (pulpwood logging) and in the mills (pulp and paper making) in ways which were broadly similar but different in timing and other significant respects.

Trees of Gold and Men Made Good? Grand Visions and Early Experiments in Penal Forestry in New South Wales, 1913-1938

Abstract While modern penal institutions exist, putatively, to transform the people held within them into law-abiding citizens, it is not generally recognised that since the early twentieth century, Australian and New Zealand penal systems have also sought to transform 'wastelands' into ordered, productive landscapes. In Australia, this experiment began in 1913 on the north coast of New South Wales, where small groups of prisoners were set to work creating a pine plantation. Penologists and foresters saw themselves as the architects of a grand project; men with 'wasted lives' would reclaim 'wasted land', and, in the process, reclaim themselves. Depraved city-dwelling criminals would be transformed into hardy, upright bushmen, while the unproductive native landscapes would be replaced by useful exotic softwood forests. Although these reforms were hailed as modern and progressive, a close study of the history of this scheme reveals that a range of relationships to landscapes, some very old indeed, are deeply embedded in historical understandings of human rehabilitation.

Bird research in the ACWERN lab at the Faculty of Forestry and Environmental Management, University of New Brunswick

Research on forest bird ecology in the ACWERN (Atlantic Cooperative Wildlife Ecology Research Network) lab at the University of New Brunswick, Fredericton, since 1995 has focused on assessing the relative contributions of habitat quality at large (“landscape”) and small (“local” or “stand”) spatial scales. To do so we had to develop methods for assessing key demographic components of fitness (productivity and survival) at large spatial scales. The large extent of forest cover in the Maritimes contrasts with regions where such work has traditionally been carried out, in which forest is clearly fragmented by agriculture or residential development. Our main findings are that spatial effects in highly forested landscapes can often be detected only by using species-specific habitat models, rather than broader categories such as “mature” or “softwood”, that Blackburnian Warblers (Dendroica fusca) are effective indicators of mixedwood forest but define it differently than forest managers do, and that cavity nesters (e.g., woodpeckers) may require different habitat components for nesting and feeding and so cannot be managed for solely on the basis of providing snags for nesting. Our focus has shifted recently to intensive studies on a species at risk, Bicknell's Thrush (Catharus bicknelli), which in New Brunswick breeds in man-made regenerating softwood forest stands, and assessing its response both to precommercial thinning of the breeding habitat and to effects carrying over from the winter habitat in the Caribbean. Key words: landscape effects, thresholds, survival, productivity, fitness, carry-over, habitat, fragmentation

Changes in forest biomass carbon storage in the South Carolina Piedmont between 1936 and 2005

Abstract With the widespread land-use conversion from abandoned farmlands to forests since 1930s, the Piedmont region of eastern United States has likely become an important carbon (C) sink. To quantify this potential C sink and understand its implication to the regional carbon budget and future forest management, we estimated the changes in forest biomass carbon storage in the South Carolina (SC) Piedmont between 1936 and 2005. Based on the nine periods of Forest Inventory and Analysis (FIA) data obtained for the Piedmont of South Carolina (18 counties, about 2.8 × 106 ha land area), we used allometric biomass regression equations, directly developed from recent FIA data, and biomass expansion factors to estimate the forest biomass carbon pool for each inventory year. Since 1936, the SC Piedmont forests have accumulated 81.84 Tg C due to forest expansion and regrowth, increasing from 57.36 Tg C in 1936 to 139.20 Tg C in 2005. Hardwood and softwood forests accounted for 74% (60.38 Tg C) and 26% (21.45 Tg C) of carbon accumulation during this period, respectively. The aboveground forest biomass carbon pool represented 80% or 65.17 Tg C of the total carbon accumulation while the belowground fine and coarse roots only accounted for 20% or 16.67 Tg C. From 1936 through 2005, forest carbon accumulated at a rate of 1.19 Tg C yr−1, offsetting 5.7% of CO2 emission (20.94 Tg C in 2003) of the entire state of South Carolina.

Extending timber rotations: carbon and cost implications

A number of studies have suggested that incentives for carbon sequestration could lead to longer rotation periods for even-aged managed forests. In this article we examine the potential costs and quantity of sequestered carbon from extending rotation ages in softwood forests of the southern and western USA. A model of optimal rotations when carbon is a valued asset was developed to show how optimal rotations adjust when carbon is priced. Data on 324 types and site classes of softwood forests in southern and western states of the USA were used to examine the costs of extending rotations. The results were then aggregated by applying the marginal cost curves to inventory data within each county in these states. The results indicate that in these 12 states, about 15 million tCO2 could be sequestered for less than $7/tCO2 (1 tCO2 = 1,000 kg CO2), although for substantially higher carbon prices of $55/tCO2, up to 209 million tCO2 could be sequestered. Timber prices were found to have an important influence on the marginal costs of carbon sequestration, with site quality being of secondary importance. The results also showed that at $55/tCO2 potentially 1 million ha of softwood forests could be set aside, mostly in the western states.

Nature rehabilitation by floodplain excavation: The hydraulic effect of 16 years of sedimentation and vegetation succession along the Waal River, NL

The “Ewijkse Plaat” is a floodplain along the Waal River, NL. In 1988, the floodplain was excavated as part of a program for enlargement of the discharge capacity and was assigned as a nature rehabilitation area. This paper describes the combined geomorphological and vegetation evolution of the floodplain until 16 years after the initial excavation using elevation data and data on vegetation structure derived from detailed aerial stereographic imagery. The impact of these processes on flow velocity and water surface elevation was evaluated by using a hydraulic model. Within 16 years, the excavated amount of sediment was redeposited in the area. The dominant geomorphological process after excavation was vertical accretion of the floodplain which resulted in the formation of natural levees. The amount of sedimentation was correlated to the across-floodplain flow ( R 2 = 0.89). In the research period, 41% of the sedimentation took place during two single major flood events. The creation of pioneer stages by excavation promoted softwood forest establishment, which influenced the sedimentation pattern significantly. The landscape evolved toward structure-rich vegetation. Nine years after excavation the initial hydraulic gain was lost by the combined effect of sedimentation and vegetation succession. Implications for river and nature management are discussed.

The composition and richness of Danubian floodplain forest land snail faunas in relation to forest type and flood frequency

The species richness and composition of land snail assemblages in 42 floodplain forest sites along the Danube River in Slovakia were studied to find the main ecological gradients responsible for the variation in the faunas. We found just one, but steep, ecological gradient influencing the variation of snail species composition among different floodplain forest types, reflected in the first detrended correspondence analysis axis, which explained 29.6% of total variation. Site scores on this axis were significantly correlated with site humidity (rs ¼ 20.868; P , 0.001). Significant loading on the first axis was also found for flood frequency and several vegetation descriptors. Species composition mainly reflected differences between sites without floods and the others. Species richness as well as total abundances of live individuals were not significantly controlled by any explanatory variable, although some trends could be discerned. Considering vegetation classification, substantial differences were observed between wet softwood floodplain forests and the remaining types, drier softwood forests and different types of hardwood forests, which were impossible to distinguish based on land snail assemblages. The results are discussed in relation to earlier descriptive studies, and in terms of the conservation of these threatened habitats.

Spatial distribution of carbon in natural and managed stands in an industrial forest in New Brunswick, Canada

Industrial forest could be managed to enhance carbon (C) sequestration together with other ecological and socio-economic objectives. However, this requires quantifying C dynamics of all major forest types within the management area, over the whole forest rotation. We used data from permanent sample plots and temporary forest development survey plots to generate volume yield curves and used the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) to estimate C yield and dynamics over a rotation for major forest types in northern New Brunswick, Canada. We compared C yields of natural versus managed and hardwood versus softwood forest under different silviculture treatments over the entire rotation. Carbon in 40–80-year-old and > 80-year-old tolerant hardwood stands averaged about 115 and 130–142 t ha −1, respectively, while softwood spruce ( Picea sp.)–balsam fir ( Abies balsamea (L.) Mill.) 40–80 and > 80 years old averaged 90 and 88–94 t C ha −1. Among 10 stand types, total C ranged from 50 to 109 t ha −1 at age 50 years, 92–138 t ha −1 at age 100, and 79–145 t ha −1at age 150 years. C in most stand types declined from age 100 to 150 years, except for eastern white cedar ( Thuja occidentalis L.), sugar maple ( Acer saccharum Marsh.) and yellow birch ( Betula alleghaniensis Britton). At age 100 years, planted softwood stands had 94–135 t ha −1, versus 92–117 t ha −1 for natural softwoods and 127–138 t ha −1 for natural hardwoods. Planted white spruce ( Picea glauca (Moench) Voss) and natural sugar maple and yellow birch sequestered the most C. The total C (above and belowground biomass and deadwood, excluding soil carbon) on the 428,000 ha test landbase was 35 million tonnes, or an average of 82 t ha −1.

Effects of Progressive Clearcut Logging on Newfoundland Caribou

Abstract: Logging has often been implicated in the decline of caribou (Rangifer tarandus), but its effects are incompletely understood. We used a distance‐based approach to assess the effects of progressive clearcut logging on the summer (28 May to 15 Sep) range of caribou in Newfoundland, Canada. We compared distances of random locations and of caribou, from 9 years of radiotelemetry, to landcover types across 3 spatial scales: population range, individual ranges, and radiolocations. We tested for incremental avoidance of cutovers and mature softwood forests, the preferred type for caribou and forest harvesting, while controlling for the confounding effects of each. At the individual range, females selected for hardwood and softwood forests, bogs, and barrens, and they avoided open water. Patterns for males were similar, although they avoided bogs and barrens at both scales. The sexes differed in their response to forest harvesting. Females progressively avoided cutovers, both pre‐ and postharvest, likely due to their spatial proximity. Females maintained an average of 9.2 km from active cutovers. Cutover avoidance was evident even if we controlled statistically for distances to other habitats, and it accounted for heightened disuse of softwood forests. Compared with females, males occurred in proximity, with no incremental response to clearcutting. These results imply deleterious effects of timber harvesting on female caribou. Long‐term investigations will enhance our capacity to evaluate such anthropogenic habitat changes.

Response of ground-dwelling beetle (Coleoptera) assemblages to giant knotweed (Reynoutria spp.) invasion

Giant knotweeds (Reynoutria spp.) are highly productive and aggressive invaders in riparian wetlands of Europe and North America. We sampled ground-dwelling beetles by pitfall traps from six sites comparing monotypic Reynoutria stands with the invaded native Urtica-dominated stands. Three sites were located in a semi-natural softwood forest and three sites were on a ruderal embankment. The analyses are based on a total of 13,244 individuals from 218 species. Location and site significantly influenced beetle assemblages. Moreover, there were pronounced differences between vegetation stands. The monotypic Reynoutria stands exhibited lower beetle abundance, species richness and rarefaction diversity irrespective of location. However, the negative effect on species richness, abundance and assemblage similarities were stronger on the transformed ruderal embankment than in the semi-natural softwood forest. Reynoutria invasion seems to influence microclimatic conditions. We found a higher abundance of silvicolous and a lower abundance of xerophilous ground beetles in the Reyountria stands than in the Urtica-dominated stands. Feeding guilds reacted differently to Reynoutria invasion that reduced the abundance of predators and herbivores but enhanced that of detritivores. Detritivores assumingly profit from the perennial presence of the large quantities of Reynoutria litter. We conclude that highly productive invaders pauperise the arthropod fauna and alter link strengths in trophic cascades shifting primary producer-based food webs to detritus-based food webs.