scholarly journals The influence of riparian vegetation on leaf litter inputs to Boreal Shield streams: implications for partial-harvest logging in riparian reserves

2009 ◽  
Vol 39 (5) ◽  
pp. 917-927 ◽  
Author(s):  
Elisa A. Muto ◽  
David P. Kreutzweiser ◽  
Paul K. Sibley

Litter inputs to headwater streams were measured to characterize and describe input patterns to the streams and to quantify the relationships between leaf litter inputs and surrounding riparian characteristics in Boreal Shield forests. Our goal was to provide information on litter inputs to streams in the Boreal Shield to determine if partial-harvest logging of commercial trees within riparian reserves has the potential to cause significant changes to litter inputs. Total leaf litter comprised 87% deciduous leaves and 13% conifer needles during the June to October periods. Commercial deciduous tree species accounted for approximately 50% of total deciduous leaf litter inputs. Distance-weighted deciduous basal area was the best predictor of overstorey deciduous litter (r2 = 0.597, P = <0.001), indicating that the size, abundance, and proximity of deciduous trees to streams are important to deciduous litter inputs. Leaf litter inputs to Boreal Shield streams are strongly influenced by surrounding riparian vegetation and can be effectively predicted by stem basal area. A linear regression model based on commercial deciduous tree basal area is presented that can be useful to determine the number of trees to retain within a riparian area to maintain leaf litter inputs at or near preharvest levels.

2006 ◽  
Vol 54 (2) ◽  
pp. 145 ◽  
Author(s):  
Anthony P. O'Grady ◽  
Derek Eamus ◽  
Peter G. Cook ◽  
Sebastien Lamontagne

Within Australia and globally there is considerable concern about the potential impacts of groundwater extraction on ecosystems dependent on groundwater. In this study we have combined heat pulse and isotopic techniques to assess groundwater use by riparian vegetation along the Daly River in the Northern Territory. The riparian forests of the Daly River exhibited considerable structural and floristic complexity. More than 40 tree species were recorded during vegetation surveys and these exhibited a range of leaf phonologies, implying complex patterns of water resource partitioning within the riparian forests. Water use was a function of species and season, and stand water use varied between 1.8 and 4.1 mm day–1. In general, however, water use tended to be higher in the wet season than during the dry season, reflecting the contribution to stand water use by dry-season deciduous tree species. There was a strong relationship between stand basal area and stand water use in the wet season, but the strength of this relationship was lower in the dry season. The amount of groundwater use, as determined by analysis of deuterium concentrations in xylem sap, was principally a function of position in the landscape. Trees at lower elevations, closer to the river, used more groundwater than trees higher on the levees. By using a combination of techniques we showed that riparian vegetation along the Daly River was highly groundwater dependent and that these water-use requirements need to be considered in regional management plans for groundwater.


2005 ◽  
Vol 35 (3) ◽  
pp. 610-622 ◽  
Author(s):  
EH (Ted) Hogg ◽  
James P Brandt ◽  
B Kochtubajda

Trembling aspen (Populus tremuloides Michx.) is the most important deciduous tree in the North American boreal forest and is also the dominant tree in the aspen parkland zone along the northern edge of the Canadian prairies. Since the 1990s, observations of dieback and reduced growth of aspen forests have led to concerns about the potential impacts of climate change. To address these concerns, a regional-scale study (CIPHA) was established in 2000 that includes annual monitoring of forest health and productivity of 72 aspen stands across the western Canadian interior. Tree-ring analysis was conducted to determine the magnitude and cause of temporal variation in stand growth of aspen at the scale (1800 km × 500 km area) encompassed by this study. The results showed that during 1951–2000 the region's aspen forests underwent several cycles of reduced growth, notably between 1976 and 1981, when mean stand basal area increment decreased by about 50%. Most of the growth variation was explained by interannual variation in a climate moisture index in combination with insect defoliation. The results of the analysis indicate that a major collapse in aspen productivity likely occurred during the severe drought that affected much of the region during 2001–2003.


2013 ◽  
Vol 6 (3) ◽  
pp. 173-177 ◽  
Author(s):  
Rodrigo Aranda

A configuração do habitat é um dos fatores que pode influenciar a distribuição dos organismos. O pantanal por apresentar mosaico natural de formações se enquadra para testar tais afirmações. O presente estudo teve como objetivo avaliar se a distância e o tamanho de capões afetam a composição da comunidade de artrópodes testando a hipótese de que quanto maior e mais próximo o capão da mata ciliar, maior sua diversidade. Foram amostradas seis parcelas de 30 cm² em nove capões onde a serrapilheira e o solo foram coletados, acondicionados em sacos plásticos e posteriormente triados. Houve relação entre a composição da comunidade de artrópodes em relação à distância e o tamanho indicando que o pulso de inundação do último ano afetou de forma significativa a comunidade de artrópodes de solo em capões. O acompanhamento dos processos de recolonização dos capões é sugerido. Capons as Island for Arthropods in Pantanal Abstract. The configuration of habitat is one of the factors that influence the distribution of organisms. The Pantanal by presenting mosaic natural formations fit to test such claims. The present study aimed to evaluate the distance and size of riparian capons affect the community composition of arthropods tested the hypothesis that the higher and closer to the capon of riparian vegetation, the greater its diversity. We sampled six plots of 30 cm² in nine capons where the leaf-litter and soil were collected, placed in plastic bags and later sorted. There was a relationship between the composition of arthropod community in relation to distance and size indicating that the flood pulse of the last year significantly affected the community of soil arthropods in geldings. The monitoring of the processes of recolonization of the capons is suggested.


Author(s):  
Kiros Abay ◽  
Kahsu Gebretsion

Aims: The aim of the study was to investigate the regeneration status and importance of Hypahene thebaica L. and associated species in Tekeze riparian vegetation of the North western zone of Tigray, Northern Ethiopia.  Study Design: Systematic sampling technique. Place and Duration of Study: The study was carried out along Tekeze riverine vegetation, northern Ethiopia between January 2015 and March 2015. Methodology: Three transects (one and two transects on the right and left side of the Tekeze River, respectively) were laid. The distance between the two transects on the left side of the river was 200 m. Along the transects, 30 plots were established systematically at intervals of 100 m to collect vegetation data. Results:  Eighteen plant species belonging to 12 families were recorded. Fabaceae was found to be the dominant family in the study area and were represented by five species, which contributed to 27.7% of the total species documented, whereas nine families were represented by one species each. The overall density of the study area was 70.97 individuals/ha. Hyphaene thebaica was the second abundant species with 16.13 individuals/ha, and contributed 22.7% to the total density of the riparian vegetation. The total basal area of plants was 1.03 m2 ha-1. Hyphaene thebaica was ranked third and accounts for 12.6% of the total basal area with 0.13 m2 ha-1. The species was the most frequent with 17.02%, followed by Ricinus communis and Balanites aegyptiaca. Balanites aegyptiaca (53.52%), H. thebaica (52.37%) and Ricinus communis (51.76%) were the three most important species. Conclusion: More mature trees were documented than saplings and seedlings, indicating “poor’’ regeneration status for the riparian vegetation. Hyphaene thebaica has shown “fair’’, while most species were found to have “poorly’’ or “no’’ regenerating. Hence a sound management plan is urgently required to sustainably utilize and conserve the riverine vegetation. 


2000 ◽  
Vol 17 (3) ◽  
pp. 100-109 ◽  
Author(s):  
D.G. Pitt ◽  
Andrée E. Morneault ◽  
Philip Bunce ◽  
F.Wayne Bell

Abstract Five years of data on vegetation dynamics and succession are provided for six operational release treatments applied to three 2- to 4-yr-old jack pine (Pinus banksiana Lamb.) plantations in central Ontario. Treatments included 3 yr of annual noncrop vegetation removal, conventional aerial spray with glyphosate (1.42 kg ae/ha), ground application of glyphosate with a mist blower, basal-bark application of triclopyr, motor-manual cutting (brush saw), and no treatment. Conventional aerial spraying and annual removal resulted in the greatest jack pine crop growth, with trees exceeding 90% crown closure, 7 cm in groundline diameter, and 3 m in height (stem volume index = 5.1 dm³) after 5 growing seasons. The cover of herbaceous plants was highest (30–50%) in the aerial spray plots during the observation period. Deciduous tree, shrub, and fern species remained well represented on these plots, although total cover and height were low (≤ 35% and 1 m, respectively). Mist-blower and brush-saw plots contained mid-sized pine (3.5 dm³) with 69% crown closure. In contrast, untreated and basal-bark plots contained the smallest pine (2.3 dm3 and 31% crown closure), likely caused by heavy competition and herbicide damage, respectively. On mist-blower and basal-bark plots, good height growth was observed on untreated deciduous trees; low-shrub and fern cover remained high (46 and 30%, respectively); and herbaceous cover increased gradually to 22%. On brush-saw plots, recovery of woody cover was rapid, but height growth was relatively slow. Deciduous trees and tall shrubs dominated untreated sites (> 70% cover) by the end of the fifth growing season. Successional trends suggest that aerial spray and annual removal treatments will produce pure jack pine stands at maturity; mist blower, basal bark, and brush-saw treatments may produce mixedwood stands; and untreated plots will likely be dominated by hardwoods. North. J. Appl. For. 17(3):100–109.


2013 ◽  
Vol 89 (03) ◽  
pp. 350-359 ◽  
Author(s):  
Nicole J. Fenton ◽  
Louis Imbeau ◽  
Timothy Work ◽  
Jenna Jacobs ◽  
Hervé Bescond ◽  
...  

Multi-cohort management that creates or maintains an uneven structure within forest stands has been widely advocated as a means to attenuate the impact of forest harvesting. An experimental network was put in place in black spruce forests of northwestern Québec to test this assertion. Here we synthesize the biodiversity results in two main lessons: (1) at least 40% to 60% retention of pre-harvest basal area was required to maintain pre-harvest conditions for most species groups; (2) partial harvests showed the potential to be efficient deadwood delivery systems. In addition to these two main general conclusions, we emphasise that future research should examine whether partial harvest may be able to advance forest succession.


1972 ◽  
Vol 2 (02) ◽  
pp. 217-231 ◽  
Author(s):  
Eberhard Grüger

Pollen and macrofossil evidence for the nature of the vegetation during glacial and interglacial periods in the regions south of the Wisconsinan ice margin is still very scarce. Modern opinions concerning these problems are therefore predominantly derived from geological evidence only or are extrapolated from pollen studies of late Wisconsinan deposits. Now for the first time pollen and macrofossil analyses are available from south-central Illinois covering the Holocene, the entire Wisconsinan, and most probably also Sangamonian and late Illinoian time. The cores studied came from three lakes, which originated as kettle holes in glacial drift of Illinoian age near Vandalia, Fayette County. The Wisconsinan ice sheet approached the sites from the the north to within about 60 km distance only.One of the profiles (Pittsburg Basin) probably reaches back to the late Illinoian (zone 1), which was characterized by forests with muchPicea. Zone 2, most likely of Sangamonian age, represents a period of species-rich deciduous forests, which must have been similar to the ones that thrive today south and southeast of the prairie peninsula. During the entire Wisconsinan (14C dates ranging from 38,000 to 21,000 BP) thermophilous deciduous trees likeQuercus, Carya, andUlmusoccurred in the region, although temporarily accompanied by tree genera with a more northerly modern distribution, such asPicea, which entered and then left south-central Illinois during the Woodfordian. Thus it is evident that arctic climatic conditions did not prevail in the lowlands of south-central Illinois (about 38°30′ lat) during the Wisconsinan, even at the time of the maximum glaciation, the Woodfordian. The Wisconsinan was, however, not a period of continuous forest. The pollen assemblages of zone 3 (Altonian) indicate prairie with stands of trees, and in zone 4 the relatively abundantArtemisiapollen indicates the existence of open vegetation and stands of deciduous trees,Picea, andPinus. True tundra may have existed north of the sites, but if so its pollen rain apparently is marked by pollen from nearby stands of trees. After the disappearance ofPinusandPiceaat about 14,000 BP (estimated!), there developed a mosaic of prairies and stands ofQuercus, Carya, and other deciduous tree genera (zone 5). This type of vegetation persisted until it was destroyed by cultivation during the 19th and 20th century. Major vegetational changes are not indicated in the pollen diagram for the late Wisconsinan and the Holocene.The dating of zones 1 and 2 is problematical because the sediments are beyond the14C range and because of the lack of stratigraphic evidence. The zones dated as Illinoian and Sangamonian could also represent just a Wisconsinan stadial and interstadial. This possibility, however, seems to be contradicted by the late glacial and interglacial character of the forest vegetation of that time.


2014 ◽  
Vol 74 (2) ◽  
pp. 267-273 ◽  
Author(s):  
VC. Oliveira ◽  
EA. Gonçalves ◽  
RG. Alves

Riparian vegetation along streams in the Atlantic Forest in Brazil contributes to the formation of a highly heterogeneous leaf litter in streambeds. To investigate the structure and composition of the aquatic invertebrate community during the process of leaf decomposition of two plant species present along the banks of the stream studied, 21 plastic mesh bags containing 2.5g (dry weight) of leaf matter from each species (Alchornea glandulosa (Vell) and Cabralea canjerana End. and Poeppig), for a total of 5.0g, were placed in the streambed. Three bags were removed after 3, 6, 9, 12, 24, 48 and 96 days. The taxonomic density was negatively correlated with the remaining weight. The high density of collector organisms, such as Chironomidae, Oligochaeta and Amphipoda, on the last day of incubation, probably occurred due to the increased amount of fine organic matter in the more advanced decomposition stages. The highest α diversity (Shannon-Wiener) values were observed for the 3rd and 96th days of the experiment, while the β diversity values showed that these days presented the highest variation in the taxonomic composition, thus presenting a different faunistic composition. This study showed that the trophic structure and composition of aquatic invertebrates changes during the decomposition of leaf litter. The faunistic abundance and diversity observed in this study indicate that the entrance of material from plants growing along streams provides favorable conditions for the colonisation and establishment of invertebrates in lower-order streams, and thus points to the need to preserve riparian vegetation.


2013 ◽  
Vol 43 (8) ◽  
pp. 731-741 ◽  
Author(s):  
Christoph Straub ◽  
Christoph Stepper ◽  
Rudolf Seitz ◽  
Lars T. Waser

Current technical advances in the field of digital photogrammetry demonstrate the great potential of automatic image matching for deriving dense surface measurements of the forest canopy. In contrast to airborne laser scanning (ALS), aerial stereo images are updated more regularly by national or regional mapping agencies in several countries. Frequently, ALS-based terrain models (DTMs) are available, and thus photogrammetric canopy heights can be derived. However, currently, there is little knowledge as to how accurately forest attributes can be modeled using the aerial stereo images acquired by these official, regular aerial surveys, especially for mixed forests in central Europe. Thus, a photogrammetric point cloud derived from UltraCamX stereo images in combination with an ALS-DTM and a classification of coniferous and deciduous tree regions (based on orthoimages) was used to create a stratified estimation of timber volume and basal area in a mixed forest in Germany. Suitable models were derived at the plot level using explanatory variables from the photogrammetric point cloud (which was normalized using an ALS-DTM). The prior stratification of conifer- and deciduous-dominated field plots slightly improved the estimation accuracy. The results verify that stereo images can be an alternative to ALS data for modeling key forest attributes, even in mixed central European forests with complex structure.


2010 ◽  
Vol 86 (5) ◽  
pp. 601-607 ◽  
Author(s):  
Stephen B. Holmes ◽  
David P. Kreutzweiser ◽  
Peter S. Hamilton

The placement of riparian setbacks around water bodies has been shown to reduce logging impacts on aquatic and riparian communities and processes. However, the systematic application of no-harvest riparian setbacks can result in unnatural, linear patterns of older-growth forest across the landscape, a pattern that is inconsistent with the goal of emulating natural disturbances. Partial harvesting within riparian zones could provide a partial solution to this problem. As part of a larger project to evaluate the environmental consequences of partial harvesting within stream riparian zones of boreal mixedwood forests, we measured wood volumes removed from riparian zones and compared feller buncher productivity between partially harvested riparian zones and adjacent clearcut uplands. On average, from 20% to 33% of the total basal area (27% to 39% of the spruce/pine/fir basal area) was removed from the riparian zones. The riparian harvest resulted in considerable heterogeneity in residual stand structure, however, with basal areas within 50-m segments along the streams ranging from just over 50% to >95% remaining. Our results suggest that, even though the absolute effort required to harvest trees was greater in riparian zones, the larger average size of the trees more than compensated, so that the wood volume removed per unit effort was higher in riparian zones than in clearcuts. Key words: machine productivity, partial harvest, residual stand structure, riparian zone


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