scholarly journals Allometric Equations for Estimating Biomass and Carbon Stocks in Afforested Open Woodlands with Black Spruce and Jack Pine, in the Eastern Canadian Boreal Forest

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Olivier Fradette ◽  
Charles Marty ◽  
Pascal Tremblay ◽  
Daniel Lord ◽  
Jean-François Boucher
Keyword(s):  
Large Scale ◽  
Ad Hoc ◽  
Black Spruce ◽  
Tree Height ◽  
Jack Pine ◽  
Carbon Stocks ◽  
Allometric Equations ◽  
C Stocks ◽  
The Difference ◽  
Canadian Boreal Forest

Allometric equations use easily measurable biometric variables to determine the aboveground and belowground biomasses of trees. Equations produced for estimating the biomass within Canadian forests at a large scale have not yet been validated for eastern Canadian boreal open woodlands (OWs), where trees experience particular environmental conditions. In this study, we harvested 167 trees from seven boreal OWs in Quebec, Canada for biomass and allometric measurements. These data show that Canadian national equations accurately predict the whole aboveground biomass for both black spruce and jack pine trees, but underestimated branches biomass, possibly owing to a particular tree morphology in OWs relative to closed-canopy stands. We therefore developed ad hoc allometric equations based on three power models including diameter at breast height (DBH) alone or in combination with tree height (H) as allometric variables. Our results show that although the inclusion of H in the model yields better fits for most tree compartments in both species, the difference is minor and does not markedly affect biomass C stocks at the stand level. Using these newly developed equations, we found that carbon stocks in afforested OWs varied markedly among sites owing to differences in tree growth and species. Nine years after afforestation, jack pine plantations had accumulated about five times more carbon than black spruce plantations (0.14 vs. 0.80 t C·ha−1), highlighting the much larger potential of jack pine for OW afforestation projects in this environment.

scholarly journals ESL in Australia – A chequered history

2016 ◽  
Vol 26 (1) ◽  
Author(s):  
Rhonda Oliver ◽  
Judith Rochecouste ◽  
Bich Nguyen
Keyword(s):  
World War Ii ◽  
Large Scale ◽  
English Language ◽  
Ad Hoc ◽  
Language Instruction ◽  
English Language Teaching ◽  
Post Colonial ◽  
White Middle Class ◽  
Constant State ◽  
The Difference

A historical perspective of English as a second or additional language (ESL/EAL) in Australia reveals the field as in a constant state of flux, in spite of Australia’s status as a nation of immigrants. This paper provides a contemporary review of the various phases of English language teaching in Australia for both adults and school-aged learners. It does so in the context of earlier pro-British monolingual attitudes, external global forces, ongoing changes in education policy, more recent national assessment regimes and the various global and local developments in the teaching of second languages. Historically the impetus for teaching English as a Second Language came with large-scale post-World War II arrivals from Europe. Language support for child migrants was only introduced some time later and has continued, although decreasing in availability in recent years. From the 1970s, more focussed programs were instigated with the arrival of refugees from war-torn countries. In this paper we describe the constant changes experienced by the providers and the recipients of English language instruction in Australia. Theoretically, the development of ESL instruction in Australia began with an essentially post-colonial perspective whereby the process of assimilation focussed on normalising the difference and/or deficit of non-English speakers and attaining the language skills of normative white middle-class native speakers (Pavlenko, 2003). Despite various investments in multiculturalism, the non-native English speaker in Australia remains the ‘other’, subject to sometimes intermittent and ad hoc funded assistance. 

scholarly journals Autonomous Clustering Scheme for Removing the Effects of Heterogeneous Node Degrees in Ad Hoc Networks

2016 ◽  
Vol 21 (2) ◽  
pp. 43-54
Author(s):  
Ryosuke Morita ◽  
Chisa Takano ◽  
Masaki Aida
Keyword(s):  
Ad Hoc Networks ◽  
Large Scale ◽  
Ad Hoc ◽  
Cluster Head ◽  
Node Degree ◽  
Hierarchical Routing ◽  
Mobile Ad Hoc ◽  
The Difference ◽  
Hoc Networks ◽  
Heterogeneous Node

Abstract In large scale mobile ad hoc networks (MANETs), it is effective to reduce the load of routing by introducing hierarchical routing, and it is conducted by clustering of nodes. A clustering mechanism based on the diffusion equation is a typical autonomous clustering in MANETs, and gives appropriate clustering if all the node degrees are uniform. However, node degrees in MANETs are heterogeneous in general, the fact causes the difference in the strength of diffusion effect. This difference causes that the position of cluster head tends to be around the boundary of networks and degrade battery efficiency of nodes. In this paper, by introducing an asymmetric diffusion depending on node degree, we propose a new clustering method independent of heterogeneity of node degrees. We show that the proposed method has efficient characteristics for battery consumption. In addition, we show the comparison of the proposed method with the conventional method with respect to the efficiency of routing.

The allometric relationships for estimating above-ground biomass and carbon stock in an abandoned traditional garden in East Kalimantan, Indonesia

2021 ◽  
Vol 22 (2) ◽  
Author(s):  
Karyati Karyati ◽  
Kusno Yuli Widiati ◽  
Karmini Karmini ◽  
Rachmad Mulyadi
Keyword(s):  
Aboveground Biomass ◽  
Carbon Stock ◽  
Global Climate ◽  
Tree Height ◽  
Carbon Stocks ◽  
Allometric Equations ◽  
Leaf Biomass ◽  
Allometric Relationships ◽  
Plant Parts ◽  
East Kalimantan

Abstract. Karyati, Widiati KY, Karmini, Mulyadi R. 2021. The allometric relationships for estimating aboveground biomass and carbon stock in an abandoned traditional garden in East Kalimantan, Indonesia. Biodiversitas 22: 751-762. The existence of traditional gardens after abandonment process has a role based on ecological and economic aspects. To estimate the biomass and carbon stock in the abandoned traditional gardens, specific allometric equations are required. The aim of this study was to develop allometric equations to estimate biomass of plant parts (leaf, branch, trunk, and aboveground biomass (AGB)) through tree dimensions variables (diameter at breast height (DBH), total tree height, and tree bole height). The relationships between stem biomass, AGB and tree dimensions were very strong indicated by the relatively high adjusted R2 value. The moderately strong relationships were shown between branch biomass and tree dimensions, meanwhile, the relationship between leaf biomass and tree dimensions was very weak. The specific allometric equations for estimating biomass and carbon stocks that are suitable for tree species and/or forest stands at a particular site are very useful for calculating the carbon stocks and sequestration. The appropriate biomass and carbon stock calculation are needed to determine policies related to global climate change.

Estimating top-kill volumes with large-scale photos on trees defoliated by the jack pine budworm

1993 ◽  
Vol 23 (7) ◽  
pp. 1337-1346 ◽  
Author(s):  
R.J. Hall ◽  
S.J. Titus ◽  
W.J.A. Volney
Keyword(s):  
Large Scale ◽  
Linear Models ◽  
Linear Equations ◽  
Tree Height ◽  
Ordinary Least Squares ◽  
Jack Pine ◽  
Alternative Methodology ◽  
Sampling Procedures ◽  
Volume Estimates ◽  
Taper Model

The estimation of tree top-kill volumes is an important component of quantifying defoliation impact of severe budworm (Choristoneurapinus Freeman) defoliation on jack pine (Pinusbanksiana Lamb.) trees. Field survey is the only method by which this assessment is currently undertaken. This study evaluated an alternative methodology based on large-scale aerial photo (1:900) measurements and a taper model fitted for jack pine. This included generating linear models for the prediction of actual top-kill length from photo-measured top-kill length, the prediction of DBH from photo-measured tree height and crown area, and the estimation of top-kill volumes from a jack pine taper model. The set of three linear equations fitted with ordinary least squares resulted in top-kill volume estimates that showed no bias. The volume of damaged trees not visible on photographs was less than 1% of the volume of all damaged trees, and therefore adjustment for missed trees was not considered necessary. The methodology is convenient to implement, and if combined with forest sampling procedures, the projection of tree top-kill volumes to the stand level can provide an estimate of defoliation impact. The methodology is also potentially suitable for assessing other insect defoliation impacts that cause top kill.

Régénération après feu de l'épinette noire (Piceamariana) et du pin gris (Pinusbanksiana) dans la forêt boréale, Québec

1992 ◽  
Vol 22 (4) ◽  
pp. 474-481 ◽  
Author(s):  
Hélène St-Pierre ◽  
Réjean Gagnon ◽  
Pierre Bellefleur
Keyword(s):  
Age Structure ◽  
Black Spruce ◽  
Time Lag ◽  
Age Determination ◽  
Jack Pine ◽  
Growing Seasons ◽  
Postfire Regeneration ◽  
Adult Trees ◽  
The Difference ◽  
Mature Stands

Age structure analysis was performed in black spruce (Piceamariana (Mill.) B.S.P.) and jack pine (Pinusbanksiana Lamb.) stands following fire (i) to determine if there is a time lag between black spruce and jack pine establishment and (ii) to compare the composition of the regeneration with regard to the original stand. The study was conducted in an area burnt in 1983, 100 km northwest of Lake Saint-Jean, Quebec. Five years after fire, the age structure of the regeneration shows an early establishment of jack pine and black spruce, with more than 95% of the seedlings established during the first three growing seasons after fire (excluding the year of fire). The age structures were similar in mature stands and in the regeneration for the jack pine while they differed for black spruce. Errors in age determination due to suppression of adult trees sampled or other causes could explain the difference in the establishment pattern of young and mature black spruces. Compared with the mature stand, the postfire regeneration had an increased proportion of jack pine. The study concludes that both species can regenerate shortly after fire, but in somewhat varying proportions.

scholarly journals Age-related and stand-wise estimates of carbon stocks and sequestration in the aboveground coarse wood biomass of wetland forests in the northern Pantanal, Brazil

2011 ◽  
Vol 8 (11) ◽  
pp. 3407-3421 ◽  
Author(s):  
J. Schöngart ◽  
J. Arieira ◽  
C. Felfili Fortes ◽  
E. Cezarine de Arruda ◽  
C. Nunes da Cunha
Keyword(s):  
Measurement Errors ◽  
Cultural Landscape ◽  
Tree Height ◽  
C Sequestration ◽  
Carbon Stocks ◽  
Wood Biomass ◽  
Allometric Models ◽  
Age Related ◽  
C Stocks ◽  
Wetland Forests

Abstract. In this study we use allometric models combined with tree ring analysis to estimate carbon stocks and sequestration in the aboveground coarse wood biomass (AGWB) of wetland forests in the Pantanal, located in central South America. In four 1-ha plots in stands characterized by the pioneer tree species Vochysia divergens Pohl (Vochysiaceae) forest inventories (trees ≥10 cm diameter at breast height, D) have been performed and converted to estimates of AGWB by two allometric models using three independent parameters (D, tree height H and wood density ρ). We perform a propagation of measurement errors to estimate uncertainties in the estimates of AGWB. Carbon stocks of AGWB vary from 7.8 ± 1.5 to 97.2 ± 14.4 Mg C ha−1 between the four stands. From models relating tree ages determined by dendrochronological techniques to C-stocks in AGWB we derived estimates for C-sequestration which differs from 0.50 ± 0.03 to 3.34 ± 0.31 Mg C ha−1 yr−1. Maps based on geostatistic techniques indicate the heterogeneous spatial distribution of tree ages and C-stocks of the four studied stands. This distribution is the result of forest dynamics due to the colonizing and retreating of V. divergens and other species associated with pluriannual wet and dry episodes in the Pantanal, respectively. Such information is essential for the management of the cultural landscape of the Pantanal wetlands.

Modelling knot morphology as a function of external tree and branch attributes

2013 ◽  
Vol 43 (3) ◽  
pp. 266-277 ◽  
Author(s):  
E. Duchateau ◽  
F. Longuetaud ◽  
F. Mothe ◽  
C. Ung ◽  
D. Auty ◽  
...  
Keyword(s):  
Tree Growth ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Three Dimensional ◽  
Tree Height ◽  
Jack Pine ◽  
Weibull Function ◽  
Data Set ◽  
External Branch ◽  
Tree Characteristics

Existing models for describing knot morphology are typically based on polynomial functions with parameters that are often not biologically interpretable. Hence, they are difficult to integrate into tree growth simulators due to the limited possibilities for linking knot shape to external branch and tree characteristics. X-ray computed tomography (CT) images taken along the stems of 16 jack pine (Pinus banksiana Lamb.) trees and 32 black spruce (Picea mariana (Mill.) B.S.P.) trees were used to extract the three-dimensional shape of 3450 and 11 276 knots from each species, respectively. Using a nonlinear approach, we firstly fitted a model of knot geometry adapted from a Weibull function. Separate equations were used to describe both the curvature and the diameter of the knot along its pith. Combining these two equations gave an accurate representation of knot shape using only five parameters. Secondly, to facilitate the integration of the resulting model into a tree growth simulator, we extracted the parameters obtained for each knot and modelled them as functions of external branch and tree characteristics (e.g., branch diameter, insertion angle, position in the stem, tree height, and stem diameter). When fitted to a separate data set, the model residuals of the black spruce knot curvature equation were less than 2.9 mm in any part of the knot profile for 75% of the observations. The corresponding value from the diameter equation was 2.8 mm. In jack pine, these statistics increased to 5.4 mm and 3.2 mm, respectively. Overall, the ability to predict knot attributes from external tree- and branch-level variables has the potential to improve the simulation of internal stem properties.

Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
Single Species ◽  
Total Plasma ◽  
Control Groups ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
The Difference ◽  
The Relationship ◽  
Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

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