scholarly journals The Driving Factors of Subtropical Mature Forest Productivity: Stand Structure Matters

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 998
Author(s):  
Siyuan Ren ◽  
Qingsong Yang ◽  
Heming Liu ◽  
Guochun Shen ◽  
Zemei Zheng ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Stand Structure ◽  
Forest Productivity ◽  
Subtropical Forest ◽  
Tree Size ◽  
Above Ground Biomass ◽  
Niche Complementarity ◽  
Subtropical Forests ◽  
Ground Biomass ◽  
Size Diversity

Forest productivity (increment of above-ground biomass) is determined by biodiversity but also by stand structure attributes. However, the relative strengths of these drivers in determining productivity remain controversial in subtropical forests. In this study, we analyzed a tree growth data from 500 plots with in a 20 ha mature subtropical forest in eastern China. We used spatial simultaneous autoregressive error models to examine the effects of diversity variables (species richness, evenness, and composition), stand structural attributes (stand density, tree size range and diversity), environmental factors (topography and soil), and initial above-ground biomass (AGB) on productivity. We also applied structural equation models to quantify the relative importance of diversity, stand structure, environmental factors, and initial AGB in determining forest productivity. Our results showed that stand structure together with diversity and initial AGB governed forest productivity. Tree size diversity (DBH Shannon’s diversity index) had the largest positive effect on forest productivity. These results provide new evidence that structural explanatory variables have greater contributions to productivity for mature subtropical forests, strongly supporting the niche complementarity hypothesis. Our work highlights the importance of tree size diversity in promoting high forest productivity, and suggests that regulating and conserving complexity of forest stand structure should be among the most important goals in subtropical forest management.

scholarly journals Estimating above-ground biomass of subtropical forest using airborne LiDAR in Hong Kong

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Evian Pui Yan Chan ◽  
Tung Fung ◽  
Frankie Kwan Kit Wong
Keyword(s):  
Hong Kong ◽  
Point Cloud ◽  
Carbon Sink ◽  
Subtropical Forest ◽  
Airborne Lidar ◽  
Above Ground Biomass ◽  
Forest Protection ◽  
Subtropical Forests ◽  
Plot Size ◽  
Ground Biomass

AbstractSeventy-percent of the terrestrial area of Hong Kong is covered by vegetation and 40% is protected as the Country Park. The above-ground biomass (AGB) acts as reliable source of carbon sink and while Hong Kong has recognized the importance of carbon sink in forest and urged for forest protection in the latest strategic plan, yet no study has been conducted on assessing the baseline of terrestrial AGB and its carbon storage. This study compared and estimated the AGB by the traditional allometric modeling and the Light Detection and Ranging (LiDAR) plot metrics at plot-level in a subtropical forest of Hong Kong. The study has tested five allometric models which were developed from pantropical regions, subtropical areas and locally. The best model was then selected as the dependent variable to develop the LiDAR-derived AGB model. The raw LiDAR point cloud was pre-processed to normalized height point cloud and hence generating the LiDAR metric as independent variables for the model development. Regression models were used to estimate AGB at various plot sizes (i.e., in 10-m, 5-m and 2.5-m radius). The models were then evaluated statistically and validated by bootstrapping and leave-one-out cross validation (LOOCV). The results indicated the LiDAR metric derived from larger plot size outperformed the smaller plot size, with model R2 of 0.864 and root-mean-square-error (RMSE) of 37.75 kg/ha. It also found that pantropical model was comparable to a site-specific model when including the bioclimatic variable in subtropical forests. This study provides the approach for delineating the baseline of terrestrial above-ground biomass and carbon stock in subtropical forests upon an appropriate plot size is being deployed.

scholarly journals Stand structure-dependent mass-ratio and complementarity effects simultaneously drive aboveground biomass in temperate Quercus forests

2021 ◽  
Author(s):  
Wen-Qiang Gao ◽  
xiangdong lei ◽  
Dong-Li Gao ◽  
Yu-Tang Li
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Aboveground Biomass ◽  
Phylogenetic Diversity ◽  
Structural Equation Models ◽  
Stand Structure ◽  
Tree Size ◽  
Stand Age ◽  
Mass Ratio ◽  
Size Diversity

Aim: Forests play a key role in regulating the global carbon cycle, a substantial portion of which is stored in aboveground biomass (AGB). It is well-understood that biodiversity can increase the biomass through complementarity and mass-ratio effects, and the contribution of environmental factors and stand structure attributes to AGB was also observed. However, the relative influence of these factors in determining the AGB of Quercus forests remains poorly understood. Location: Temperate Quercus forests in northeastern China. Methods: Using a large dataset retrieved from 523 permanent forest inventory plots across Northeast China, we examined the effects of integrated multiple tree species diversity components (i.e., species richness, functional and phylogenetic diversity), functional traits composition, environmental factors (climate and soil), stand age, and structure attributes (stand density, tree size diversity) on AGB based on structural equation models. Results: We found that species richness and phylogenetic diversity both were not correlated with AGB. However, functional diversity positively affected AGB via an indirect effect in line with the complementarity effect. Moreover, the community-weighted mean of specific leaf area and height increased AGB directly and indirectly, respectively; demonstrating the mass-ratio effect. Furthermore, stand age, density, and tree size diversity were more important modulators of AGB than biodiversity. Main conclusions: Our study highlights that biodiversity-AGB interaction is dependent on the regulation of stand structure that can be even more important for maintaining high biomass than biodiversity in temperate Quercus forests.

scholarly journals Vegetation cover and carbon pool loss assessment due to extreme weather induced disaster in Mandakini valley, Western Himalaya

2020 ◽  
Vol 21 (1&2) ◽  
pp. 49-62
Author(s):  
Yogesh Kumar ◽  
Sanjay Babu ◽  
Sarnam Singh
Keyword(s):  
Forest Cover ◽  
Western Himalaya ◽  
Flash Floods ◽  
Extreme Weather ◽  
Carbon Pool ◽  
Coefficient Of Determination ◽  
Above Ground Biomass ◽  
Loss Assessment ◽  
Subtropical Forests ◽  
Ground Biomass

Sendai Framework for 2015-2030 emphasises on the damage and loss assessment needs and its ecosystem level impacts. We have assessed the loss of forest cover and phytomass/carbon pool in the natural forest ecosystems lost due to extreme weather conditions leading flash floods and landslides during Kedarnath tragedy on June 17, 2013 in Mandakini Valley, Uttarakhand in Western Himalaya. We used high resolution satellite IRS LISS IV (5.8 m spatial resolution) of pre-disaster (2012) & post-disaster (2013). Since lost vegetation cannot be ground inventoried, a new approach was developed wherein we used pre-disaster spectral characteristics to identify  sample locations in nearby and adjacent to affected areas. We laid 45 geotagged sample plots in May 2014 on both side of the 37 landslide affected areas within a distance of 2 km from river-bed for primary data collection. Above ground biomass and Carbon was estimated using standard protocols and used species-specific volumetric equations and wood density. Above ground biomass varied from 18.05t/ha in Alpine Scrub to 252.95 t/ha in Subtropical forests. Assuming that the biomass increment and spectral properties would not change significantly, we applied several vegetation indices to get best regression model with biomass.  We found NDVI (2014) with coefficient of determination (R2) of 0.893, SE± 0.038 with linear function as the best for geospatial modelling of the biomass for pre-flood 2013 and post-flood 2014 situations. Coefficient of determination (R²) between estimated vis-à-vis modelled biomass was 0.8643. It is found that there is a net loss of 52,055.80 tonnes of forest biomass and 24,466.14 tonnes of carbon due to landslides and flash floods. The maximum biomass/carbon was lost in the sub-tropical forests. The loss of forest cover was maximum in subtropical forests.

scholarly journals Biomass and dominance of conservative species drive above-ground biomass productivity in a mediterranean-type forest of Chile

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Ariel Isaías Ayma-Romay ◽  
Horacio E. Bown
Keyword(s):  
Biomass Productivity ◽  
Well Being ◽  
Mediterranean Forests ◽  
Mass Ratio ◽  
Above Ground Biomass ◽  
Niche Complementarity ◽  
Soil Resources ◽  
Ground Biomass ◽  
Wide Range ◽  
Chilean Matorral

Abstract Background Forest productivity has a pivotal role in human well-being. Vegetation quantity, niche complementarity, mass-ratio, and soil resources are alternative/complementary ecological mechanisms driving productivity. One challenge in current forest management depends on identifying and manipulating these mechanisms to enhance productivity. This study assessed the extent to which these mechanisms control above-ground biomass productivity (AGBP) of a Chilean mediterranean-type matorral. AGBP measured as tree above-ground biomass changes over a 7-years period, was estimated for twelve 25 m × 25 m plots across a wide range of matorral compositions and structures. Variables related to canopy structure, species and functional diversity, species and functional dominance, soil texture, soil water and soil nitrogen content were measured as surrogates of the four mechanisms proposed. Linear regression models were used to test the hypotheses. A multimodel inference based on the Akaike’s information criterion was used to select the best models explaining AGBP and for identifying the relative importance of each mechanism. Results Vegetation quantity (tree density) and mass-ratio (relative biomass of Cryptocarya alba, a conservative species) were the strongest drivers increasing AGBP, while niche complementarity (richness species) and soil resources (sand, %) had a smaller effect either decreasing or increasing AGBP, respectively. This study provides the first assessment of alternative mechanisms driving AGBP in mediterranean forests of Chile. There is strong evidence suggesting that the vegetation quantity and mass-ratio mechanisms are key drivers of AGBP, such as in other tropical and temperate forests. However, in contrast with other studies from mediterranean-type forests, our results show a negative effect of species diversity and a small effect of soil resources on AGBP. Conclusion AGBP in the Chilean matorral depends mainly on the vegetation quantity and mass-ratio mechanisms. The findings of this study have implications for matorral restoration and management for the production of timber and non-timber products and carbon sequestration.

scholarly journals Complementarity effects on tree growth are contingent on tree size and climatic conditions across Europe

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jaime Madrigal-González ◽  
Paloma Ruiz-Benito ◽  
Sophia Ratcliffe ◽  
Joaquín Calatayud ◽  
Gerald Kändler ◽  
...  
Keyword(s):  
Large Scale ◽  
Stand Structure ◽  
Tree Size ◽  
Tree Level ◽  
Permanent Plots ◽  
Growth Responses ◽  
Niche Complementarity ◽  
Growth Increments ◽  
Large Trees ◽  
Complementarity Effects

Abstract Neglecting tree size and stand structure dynamics might bias the interpretation of the diversity-productivity relationship in forests. Here we show evidence that complementarity is contingent on tree size across large-scale climatic gradients in Europe. We compiled growth data of the 14 most dominant tree species in 32,628 permanent plots covering boreal, temperate and Mediterranean forest biomes. Niche complementarity is expected to result in significant growth increments of trees surrounded by a larger proportion of functionally dissimilar neighbours. Functional dissimilarity at the tree level was assessed using four functional types: i.e. broad-leaved deciduous, broad-leaved evergreen, needle-leaved deciduous and needle-leaved evergreen. Using Linear Mixed Models we show that, complementarity effects depend on tree size along an energy availability gradient across Europe. Specifically: (i) complementarity effects at low and intermediate positions of the gradient (coldest-temperate areas) were stronger for small than for large trees; (ii) in contrast, at the upper end of the gradient (warmer regions), complementarity is more widespread in larger than smaller trees, which in turn showed negative growth responses to increased functional dissimilarity. Our findings suggest that the outcome of species mixing on stand productivity might critically depend on individual size distribution structure along gradients of environmental variation.

scholarly journals Epiphyte biomass and nutrient capital of a moist subtropical forest in north-eastern Taiwan

2002 ◽  
Vol 18 (5) ◽  
pp. 659-670 ◽  
Author(s):  
Chia-Chun Hsu ◽  
Fu-Wen Horng ◽  
Chen-Meng Kuo
Keyword(s):  
Nutrient Cycling ◽  
Nutrient Content ◽  
Subtropical Forest ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
North Eastern ◽  
Tree Foliage

A plot of 1200 m2 was selected to represent the average epiphyte abundance of a moist subtropical broadleaved forest at Fushan in north-eastern Taiwan. In this plot, all epiphytes of 18 sample trees with dbh > 5 cm were removed and weighed to estimate their biomass and nutrient content. We found that the biomass of epiphytes and their associated detrital matter in this plot was 3360 kg ha-1. The nutrient capital of the epiphytes (kg ha-1) was: N = 42.4, P = 1.9, Mg = 5.5, Na = 1.3, Ca = 14.5 and K = 28.9. Although the epiphytic biomass constituted less than 2% of the total above-ground biomass of the forest, the epiphytes comprised about 21-43% of the total foliage nutrient capital of the ecosystem. Because nutrients contained in epiphytes and tree foliage are more readily available to other organisms than those in woody components, epiphytes may play a greater role in ecosystem nutrient cycling than their relatively small biomass would suggest.

Changes in tree size, not species diversity, underlie the low above‐ground biomass in natural forest edges

2021 ◽  
Vol 32 (2) ◽  
Author(s):  
Mateus Cardoso Silva ◽  
Felipe Pimentel Lopes Melo ◽  
Eduardo Berg
Keyword(s):  
Species Diversity ◽  
Natural Forest ◽  
Tree Size ◽  
Forest Edges ◽  
Above Ground Biomass ◽  
Ground Biomass

Climate and large-sized trees, but not diversity, drive above-ground biomass in subtropical forests

2021 ◽  
Vol 490 ◽  
pp. 119126
Author(s):  
Kauane Maiara Bordin ◽  
Adriane Esquivel-Muelbert ◽  
Rodrigo Scarton Bergamin ◽  
Joice Klipel ◽  
Rayana Caroline Picolotto ◽  
...  
Keyword(s):  
Above Ground Biomass ◽  
Subtropical Forests ◽  
Ground Biomass

scholarly journals Above-ground Biomass Estimation of Subtropical Forest in Hong Kong using Airborne LiDAR

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Puiyan Chan ◽  
Tung Fung ◽  
Frankie K.K. Wong
Keyword(s):  
Hong Kong ◽  
Subtropical Forest ◽  
Airborne Lidar ◽  
Biomass Estimation ◽  
Above Ground Biomass ◽  
Ground Biomass

Evolutionary constraints on tree size and above‐ground biomass in tropical dry forests

2021 ◽  
Author(s):  
Natalia Aguiar‐Campos ◽  
Fernanda Coelho de Souza ◽  
Vinícius Andrade Maia ◽  
Vanessa Leite Rezende ◽  
Cleber Rodrigo Souza ◽  
...  
Keyword(s):  
Tree Size ◽  
Tropical Dry Forests ◽  
Evolutionary Constraints ◽  
Above Ground Biomass ◽  
Dry Forests ◽  
Ground Biomass
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