Mortality and Annual Changes in Distribution of Above-Ground Biomass in an Aspen Sucker Stand

1971 ◽  
Vol 1 (4) ◽  
pp. 262-266 ◽  
Author(s):  
D. F. W. Pollard

Biomass (stems and branches) increased from 17 000 kg h−1 in the 4th year to 34 000 kg h−1 in the 7th year of development of an aspen sucker stand. The bulk of the biomass was distributed in the middle and upper diameter classes of shoots; net annual increases only occurred in the upper classes. About 80% of shoots dying in the 3 years of study were less than 2 cm dbh; the biomass lost in these amounted to 200 kg h−1 or less each year. The remaining 20% mortality occurred in the 7th year among shoots 2–5 cm dbh infected with Diplodiatumefaciens. Biomass lost in these larger shoots amounted to 4 900 kg h−1; this was close to the discrepancy between net production (stems and branches) in the 7th year (2600 kg h−1 per annum) and net production in the 5th and 6th years (about 7000 kg h−1 per annum.) Results suggest that although high rates of net annual production are obtainable in short rotations, the mean annual production is strongly influenced by disease because of insufficient time for enhanced growth of survivors.

2000 ◽  
Vol 48 (6) ◽  
pp. 707 ◽  
Author(s):  
W. H. Burrows ◽  
M. B. Hoffmann ◽  
J. F. Compton ◽  
P. V. Back ◽  
L. J. Tait

Allometric equations are presented relating stem circumference to branch, leaf, trunk, bark, total above-ground and lignotuber biomass for Eucalyptus crebra F.Muell. (woodland trees), E. melanophloia Sol. Ex Gaerth. (both woodland and regrowth community trees) and E. populnea F.Muell. (woodland trees). There were no significant differences (P > 0.05) between the slopes of individual lognormal regression lines plotting stem circumference against total above-ground biomass for E. crebra, E. melanophloia and E. populnea. Root-to-shoot ratios and leaf area indices were also determined for the stands contributing to each regression. The regressions were then applied to measured eucalypt stems in the associated plant community to give estimates of each stand’s component (eucalypt tree fraction only) biomass per hectare. These eucalypt regressions were next applied to measured stems of each species on a total of 33 woodland sites in which these eucalypts individually contributed > 75% of total site basal area. Above-ground biomass/basal area relationships averaged 6.74 0.29 t m–2 basal area for 11 E. crebra sites, 5.11 0.28 t m–2 for 12 E. melanophloia sites and 5.81 0.11 t m–2 for 10 E. populnea sites. The mean relationship for all sites was 5.86 0.18 t m–2 basal area. The allometric relationships presented at both individual tree and stand levels, along with calculated biomass : basal area relationships, enable ready estimates to be made of above-ground biomass (carbon stocks) in woodlands dominated by these eucalypts in Queensland, assuming individual stem circumferences or community basal areas are known. However, to document changes in carbon stocks (e.g. for Greenhouse Gas Inventory or Carbon Offset trading purposes), more attention needs to be placed on monitoring fluxes in the independent variables (predictors) of these allometric equations.


2008 ◽  
Vol 48 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Jürgen Aosaar ◽  
Veiko Uri

Halli lepa, hübriidlepa ja arukase biomassi produktsioon endistel põllumaadel The present study is based on four experimental sites, located in Southern-Estonia: hybrid alder and grey alder plantations located in Põlva county, and two sample plots of silver birch, located in Tartu county. The stand characteristics, above-ground biomass and current annual production (CAP) were estimated in order to evaluate production capacity of different tree species growing on abandoned agricultural lands. Due to fast growth and high biomass production capacity the most promising tree species for short-rotation forestry in Estonia is grey alder. The stem mass in the 13-years-old grey alder and hybrid alder stand was 63.4 t ha-1 and 40.0 t ha-1, respectively. However, the different biomass production is mainly affected by stand densities, 6170 trees per ha and 4080 trees per ha, respectively. During ageing, the differences between the alder stands diminish. At the age of 14, mean height and diameter at breast height were practically equal. Also the mean stem mass in the older, 13-year old stand, is almost equal: 10.3 kg in grey alder stand and 9.8 kg in hybrid alder stand. At a younger age, the mean stem mass was higher in grey alder stand, but later, at the age of 13, the mean stem mass has become almost the same (10.3 kg in grey alder stand and 9.8 kg in hybrid alder stand). The rotation period for hybrid alder is longer than for grey alder and bulk maturity will occur later. Silver birch is also a highly productive tree species and has a prospect for short-rotation forestry. The mean stem mass and annual current increment of 8-year-old silver birch stand was in same the magnitude as in the grey alder stand. Although the average stand diameter and height were lower in the silver birch stand than in the grey alder stand, it is compensated by the higher wood density of birch wood. The number of trees has affected silver birch stand production, the above-ground biomass in the very high density birch stand (35 600 trees per ha) was significantly lower than in the sparse stand (11 600 trees per ha), 22.8 t ha-1 and 31.2 t ha-1, respectively.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Juha Aalto ◽  
Pekka Niittynen ◽  
Henri Riihimäki ◽  
Miska Luoto

AbstractTundra ecosystems have experienced changes in vegetation composition, distribution, and productivity over the past century due to climate warming. However, the increase in above-ground biomass may be constrained by cryogenic land surface processes that cause topsoil disturbance and variable microsite conditions. These effects have remained unaccounted for in tundra biomass models, although they can impact multiple opposing feedbacks between the biosphere and atmosphere, ecosystem functioning and biodiversity. Here, by using field-quantified data from northern Europe, remote sensing, and machine learning, we show that cryogenic land surface processes substantially constrain above-ground biomass in tundra. The three surveyed processes (cryoturbation, solifluction, and nivation) collectively reduced biomass by an average of 123.0 g m−2 (−30.0%). This effect was significant over landscape positions and was especially pronounced in snowbed environments, where the mean reduction in biomass was 57.3%. Our results imply that cryogenic land surface processes are pivotal in shaping future patterns of tundra biomass, as long as cryogenic ground activity is retained by climate warming.


2020 ◽  
Vol 8 (1) ◽  
pp. 20
Author(s):  
Erfanda Irawan ◽  
Irdika Mansur ◽  
Iwan Hilwan

Acacia mangium Willd. is categorized as an invasive species in the revegetation area of coal mining. The presence of A.mangium causes a shortage the organic matter in the revegetation area. The abundance of A. mangium biomass could be used as a source of organic material for soil enhancer to improve soil fertility. The objective of this study was to develop allometric models of Acacia mangium and to estimate the potential above-ground biomass of A. mangium in PT Wahana Baratama Mining (PT WBM). This study was conducted in February-April 2019. A. mangium population and distribution were collected through vegetation inventory with 0.5% sampling intensity. The allometric models were established using a destructive method. The above-ground biomass allometric model for the four diameter classes are as follows: seedlings (B = 0,002002 - 0,02469D + 0,07322D2 with R2(adj)= 99,38%), saplings (B = 2,754 - 1,742D + 0,4093D2 with R2(adj)= 99,89%), poles (B = -9,16 - 1,153D + 0,5007D2 with R2(adj)= 99,96%), and trees (B = 0,134741D2,38 with R2(adj)= 96,94%). The allometric models were used to estimate the above-ground biomass potential total of A. mangium by using inventory data. The inventory result showed that the mean density of A.mangium is 13.187 individuals/ha with a mean diameter of 5,64 cm. The potential above-ground biomass of A. mangium in PT WBM revegetation area is estimated at up to 51.022,59 tons. The above-ground biomass of A. mangium has potential value to be utilized as a soil enhancer as well as meet the needs of organic material for the whole PT WBM revegetation areas.Keywords: above-ground biomass, coal mining, Acacia mangium, reclamation, revegetation


FLORESTA ◽  
2010 ◽  
Vol 40 (4) ◽  
Author(s):  
Saulo Jorge Téo ◽  
Sebastião Do Amaral Machado ◽  
Carlos Bruno Reissmann ◽  
Afonso Figueiredo Filho

Esta pesquisa teve como objetivo quantificar e analisar as concentrações e conteúdos de micronutrientes da biomassa aérea de bracatinga sob diferentes classes de sítio, idade e diâmetro, na região metropolitana de Curitiba, Estado do Paraná. Foram amostradas 25 árvores em diversas localidades da área de estudo, as quais foram separadas nos seguintes compartimentos da biomassa: folhas, galhos < 4 cm, galhos ≥ 4 cm, madeira e casca do fuste. Após o levantamento de biomassa no campo, amostras foram levadas para o laboratório para a determinação do peso da massa seca e dos micronutrientes. As árvores foram agrupadas por classe de sítio, de idade e de diâmetro, as quais constituíram os tratamentos de um delineamento estatístico inteiramente casualizado. De acordo com os resultados, as concentrações de micronutrientes assumiram a seguinte ordem decrescente: Mn > Fe > Cu > Zn. O compartimento da biomassa aérea que apresentou as maiores quantidades de micronutrientes foi a madeira. As concentrações de micronutrientes não apresentaram tendências claras de aumento ou diminuição com nenhum dos fatores analisados. Somente os diâmetros exerceram efeitos significativos e consistentes sobre os conteúdos de micronutrientes da biomassa aérea de bracatinga na região metropolitana de Curitiba.Palavras-chave: Mimosa scabrella; nutrientes; ciclagem de nutrientes; biomassa. AbstractMicronutrients of above-ground bracatinga biomass under different sites, ages and diameter classes.The aims of this research were to quantify and analyze the micronutrient concentration and content of Mimosa scabrella above-ground biomass under different sites, ages and diameter classes, in Curitiba metropolitan region, Paraná State, Brazil. Twenty five trees were sampled in several localities of the study area, which were separated in different biomass components, as follow: leaves, twigs, branches, stem wood and bark. After the biomass survey in the field, samples of each tree component were carried out to the laboratory for dry weight and micronutrient determination. The trees were grouped by site, age and diameter classes, which constituted the treatments of a completely random statistical design. According to the results, the micronutrient concentrations assumed a decreasing order as follow: Mn > Fe > Cu > Zn. The stem wood presented the highest quantity of micronutrient, considering the tree above-ground biomass. The micronutrient concentrations didn’t present clear tendencies according to site, age and diameter classes. Only the diameter classes had exerted significant and coherent effects on the micronutrient contents of the studied species.Keywords: Mimosa scabrella; nutrients; nutrient cycling; biomass.


1988 ◽  
Vol 4 (3) ◽  
pp. 293-302 ◽  
Author(s):  
Lim Meng Tsai

ABSTRACTMalaysia is establishing large-scale plantations for reforestation and the production of wood for pulp and paper as well as for light construction. The main species used currently is the exotic legume Acacia mangium. The above-ground biomass, litter production and litter accumulation in a four-year-old stand in Peninsular Malaysia were studied. The mean diameter at breast height (dbh) was 12 cm. The mean annual increment (MAI) in dbh of individual trees ranged from 0.9 to 5.1 cm while MAI in height of sample trees ranged from 2.9 to 5.5 m. The total above-ground biomass of the stand was 90.4 t ha−1, consisting of 57.6 t stem, 14.1 t branch and 5.4 t leaf. Litter production averaged 10.23 t ha−1 yr−1 with leaf litter making up 87.4% of the total. Leaf litter accumulation amounted to 6.64 t ha−1 and the turnover constant of leaf litter was estimated at 1.35. The high productivity is discussed in relation to the high turnover of foliage and the low turnover of litter.


2008 ◽  
Vol 24 (4) ◽  
pp. 355-366 ◽  
Author(s):  
Jérôme Chave ◽  
Jean Olivier ◽  
Frans Bongers ◽  
Patrick Châtelet ◽  
Pierre-Michel Forget ◽  
...  

AbstractThe dynamics of tropical forest woody plants was studied at the Nouragues Field Station, central French Guiana. Stem density, basal area, above-ground biomass and above-ground net primary productivity, including the contribution of litterfall, were estimated from two large permanent census plots of 12 and 10 ha, established on contrasting soil types, and censused twice, first in 1992–1994, then again in 2000–2002. Mean stem density was 512 stems ha−1 and basal area, 30 m2 ha−1. Stem mortality rate ranged between 1.51% and 2.06% y−1. In both plots, stem density decreased over the study period. Using a correlation between wood density and wood hardness directly measured by a Pilodyn wood tester, we found that the mean wood density was 0.63 g cm−3, 12% smaller than the mean of wood density estimated from the literature values for the species occurring in our plot. Above-ground biomass ranged from 356 to 398 Mg ha−1 (oven-dry mass), and it increased over the census period. Leaf biomass was 6.47 Mg ha−1. Our total estimate of aboveground net primary productivity was 8.81 MgC ha−1 y−1 (in carbon units), not accounting for loss to herbivory, branchfalls, or biogenic volatile organic compounds, which may altogether account for an additional 1 MgC ha−1 y−1. Coarse wood productivity (stem growth plus recruitment) contributed to 4.16 MgC ha−1 y−1. Litterfall contributed to 4.65 MgC ha−1 y−1 with 3.16 MgC ha−1 y−1 due to leaves, 1.10 MgC ha−1 y−1 to twigs, and 0.39 MgC ha−1 y−1 to fruits and flowers. The increase in above-ground biomass for both trees and lianas is consistent with the hypothesis of a shift in the functioning of Amazonian rain forests driven by environmental changes, although alternative hypotheses such as a recovery from past disturbances cannot be ruled out at our site, as suggested by the observed decrease in stem density.


2013 ◽  
Vol 10 (2) ◽  
pp. 51-54
Author(s):  
Rudolf Petráš ◽  
Julian Mecko ◽  
Viera Petrášová

Abstract Calorific value production from the above-ground biomass of stands was derived from its volume production. The mathematical models of growth tables of I-214 and Robusta poplar clones, biomass density values and calorific values of biomass dry matter were used for its calculation. At the stands aged 35 years and site indices of 20, 30 and 40, the calorific value has approximately 2.700, 6.000 and 9.300 GJ.ha-1 respectively. The I-214 clone has higher production than Robusta in the first half of its growth, albeit with minimum differences. The annual increments of calorific value culminate about the age of 9-13 years with values of 450-115 GJ.ha-1. Mean annual production of both clones culminates at the age of 17-26 years with values of 320-80 GJ.ha-1. Lowland forest locations with high level of ground water in Slovakia with the total area of 25.600 ha are most suitable for poplars production. On this area, we can assume the mean annual production of 3.566 TJ of gross calorific value obtained from above-ground biomass in the future. From that, about 64% is in wood, 14% in bark and 22% in small-wood. Up to 85% of this production potential is situated in the area of The Danube Lowland and the rest is mainly in southern areas of the Central and Eastern Slovakia.


2017 ◽  
Vol 23 (2) ◽  
Author(s):  
AFSHAN ANJUM BABA ◽  
SYED NASEEM UL-ZAFAR GEELANI ◽  
ISHRAT SALEEM ◽  
MOHIT HUSAIN ◽  
PERVEZ AHMAD KHAN ◽  
...  

The plant biomass for protected areas was maximum in summer (1221.56 g/m2) and minimum in winter (290.62 g/m2) as against grazed areas having maximum value 590.81 g/m2 in autumn and minimum 183.75 g/m2 in winter. Study revealed that at Protected site (Kanidajan) the above ground biomass ranged was from a minimum (1.11 t ha-1) in the spring season to a maximum (4.58 t ha-1) in the summer season while at Grazed site (Yousmarag), the aboveground biomass varied from a minimum (0.54 t ha-1) in the spring season to a maximum of 1.48 t ha-1 in summer seasonandat Seed sown site (Badipora), the lowest value of aboveground biomass obtained was 4.46 t ha-1 in spring while as the highest (7.98 t ha-1) was obtained in summer.


2016 ◽  
Vol 13 (11) ◽  
pp. 3343-3357 ◽  
Author(s):  
Zun Yin ◽  
Stefan C. Dekker ◽  
Bart J. J. M. van den Hurk ◽  
Henk A. Dijkstra

Abstract. Observed bimodal distributions of woody cover in western Africa provide evidence that alternative ecosystem states may exist under the same precipitation regimes. In this study, we show that bimodality can also be observed in mean annual shortwave radiation and above-ground biomass, which might closely relate to woody cover due to vegetation–climate interactions. Thus we expect that use of radiation and above-ground biomass enables us to distinguish the two modes of woody cover. However, through conditional histogram analysis, we find that the bimodality of woody cover still can exist under conditions of low mean annual shortwave radiation and low above-ground biomass. It suggests that this specific condition might play a key role in critical transitions between the two modes, while under other conditions no bimodality was found. Based on a land cover map in which anthropogenic land use was removed, six climatic indicators that represent water, energy, climate seasonality and water–radiation coupling are analysed to investigate the coexistence of these indicators with specific land cover types. From this analysis we find that the mean annual precipitation is not sufficient to predict potential land cover change. Indicators of climate seasonality are strongly related to the observed land cover type. However, these indicators cannot predict a stable forest state under the observed climatic conditions, in contrast to observed forest states. A new indicator (the normalized difference of precipitation) successfully expresses the stability of the precipitation regime and can improve the prediction accuracy of forest states. Next we evaluate land cover predictions based on different combinations of climatic indicators. Regions with high potential of land cover transitions are revealed. The results suggest that the tropical forest in the Congo basin may be unstable and shows the possibility of decreasing significantly. An increase in the area covered by savanna and grass is possible, which coincides with the observed regreening of the Sahara.


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