scholarly journals Identifying Variables to Discriminate between Conserved and Degraded Forest and to Quantify the Differences in Biomass

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1020
Author(s):  
Yan Gao ◽  
Margaret Skutsch ◽  
Diana Laura Jiménez Rodríguez ◽  
Jonathan V. Solórzano
Keyword(s):  
Aboveground Biomass ◽  
Tropical Dry Forest ◽  
Canopy Cover ◽  
Basal Area ◽  
Tree Height ◽  
Dry Forest ◽  
Rank Test ◽  
Degraded Forest ◽  
Forest Survey ◽  
Structural Variables

The purpose of this work was to determine which structural variables present statistically significant differences between degraded and conserved tropical dry forest through a statistical study of forest survey data. The forest survey was carried out in a tropical dry forest in the watershed of the River Ayuquila, Jalisco state, Mexico between May and June of 2019, when data were collected in 36 plots of 500 m2. The sample was designed to include tropical dry forests in two conditions: degraded and conserved. In each plot, data collected included diameter at breast height, tree height, number of trees, number of branches, canopy cover, basal area, and aboveground biomass. Using the Wilcoxon signed-rank test, we show that there are significant differences in canopy cover, tree height, basal area, and aboveground biomass between degraded and conserved tropical dry forest. Among these structural variables, canopy cover and mean height separate conserved and degraded forests with the highest accuracy (both at 80.7%). We also tested which variables best correlate with aboveground biomass, with a view to determining how carbon loss in degraded forest can be quantified at a larger scale using remote sensing. We found that canopy cover, tree height, and density of trees all show good correlation with biomass and these variables could be used to estimate changes in biomass stocks in degraded forests. The results of our analysis will help to increase the accuracy in estimating aboveground biomass, contribute to the ongoing work on REDD+, and help to reduce the great uncertainty in estimation of emissions from forest degradation.

scholarly journals WHICH VARIABLES IN FOREST SURVEY DATA CAN BETTER DISTINGUISH CONSERVED AND DEGRADED TROPICAL DRY FOREST?

2020 ◽  
Vol XLII-3/W12-2020 ◽  
pp. 309-313
Author(s):  
Y. Gao ◽  
D. Jiménez ◽  
M. Skutsch ◽  
M. Salinas ◽  
J. Solórzano
Keyword(s):  
Statistical Study ◽  
Tropical Dry Forest ◽  
Canopy Cover ◽  
Basal Area ◽  
Remote Sensing Data ◽  
Tree Height ◽  
Forest Degradation ◽  
Dry Forest ◽  
Inventory Data ◽  
Forest Survey

Abstract. This paper presents the results of a statistical study of forest inventory data for tropical dry forest in Ayuquila River Basin, Jalisco state, Mexico. The field inventory was carried out between May-June of 2019 which is at the end of dry season and the beginning of raining season. The field inventory data were collected in 43 plots of 500 m2 each which were designed in a way to include tropical dry forests in two conditions: degraded and conserved. In each plot, the collected data include DBH, tree height, number of trees per plot, and the density of tree stems. A study was carried out to find out if there are statistically significant differences variables relating to forest structure between degraded and conserved status. The Mann-Whitney test shows that there is significant differences in canopy cover, biomass, tree height, and basal area. This information is important since it helps to understand whether and how forest degradation can be detected using remote sensing data.

scholarly journals Adjudicating Perspectives on Forest Structure: How Do Airborne, Terrestrial, and Mobile Lidar-Derived Estimates Compare?

2021 ◽  
Vol 13 (12) ◽  
pp. 2297
Author(s):  
Jonathon J. Donager ◽  
Andrew J. Sánchez Meador ◽  
Ryan C. Blackburn
Keyword(s):  
Ponderosa Pine ◽  
Laser Scanning ◽  
Canopy Cover ◽  
Basal Area ◽  
Tree Height ◽  
Absolute Error ◽  
Forest Monitoring ◽  
Individual Tree ◽  
Structural Configurations ◽  
Individual Trees

Applications of lidar in ecosystem conservation and management continue to expand as technology has rapidly evolved. An accounting of relative accuracy and errors among lidar platforms within a range of forest types and structural configurations was needed. Within a ponderosa pine forest in northern Arizona, we compare vegetation attributes at the tree-, plot-, and stand-scales derived from three lidar platforms: fixed-wing airborne (ALS), fixed-location terrestrial (TLS), and hand-held mobile laser scanning (MLS). We present a methodology to segment individual trees from TLS and MLS datasets, incorporating eigen-value and density metrics to locate trees, then assigning point returns to trees using a graph-theory shortest-path approach. Overall, we found MLS consistently provided more accurate structural metrics at the tree- (e.g., mean absolute error for DBH in cm was 4.8, 5.0, and 9.1 for MLS, TLS and ALS, respectively) and plot-scale (e.g., R2 for field observed and lidar-derived basal area, m2 ha−1, was 0.986, 0.974, and 0.851 for MLS, TLS, and ALS, respectively) as compared to ALS and TLS. While TLS data produced estimates similar to MLS, attributes derived from TLS often underpredicted structural values due to occlusion. Additionally, ALS data provided accurate estimates of tree height for larger trees, yet consistently missed and underpredicted small trees (≤35 cm). MLS produced accurate estimates of canopy cover and landscape metrics up to 50 m from plot center. TLS tended to underpredict both canopy cover and patch metrics with constant bias due to occlusion. Taking full advantage of minimal occlusion effects, MLS data consistently provided the best individual tree and plot-based metrics, with ALS providing the best estimates for volume, biomass, and canopy cover. Overall, we found MLS data logistically simple, quickly acquirable, and accurate for small area inventories, assessments, and monitoring activities. We suggest further work exploring the active use of MLS for forest monitoring and inventory.

scholarly journals Multiple Factors Influence Seasonal and Interannual Litterfall Production in a Tropical Dry Forest in Mexico

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1241
Author(s):  
Hernán Morffi-Mestre ◽  
Gregorio Ángeles-Pérez ◽  
Jennifer S. Powers ◽  
José Luis Andrade ◽  
Astrid Helena Huechacona Ruiz ◽  
...  
Keyword(s):  
Linear Models ◽  
Tropical Dry Forest ◽  
Basal Area ◽  
Dry Forest ◽  
Maximum Temperature ◽  
Dry Forests ◽  
Evergreen Species ◽  
Flat Terrain ◽  
Litterfall Production ◽  
Successional Age

Litterfall production plays a fundamental role in the dynamics and function of tropical forest ecosystems, as it supplies 70–80% of nutrients entering the soil. This process varies annually and seasonally, depending on multiple environmental factors. However, few studies spanning several years have addressed the combined effect of climate variables, successional age, topography, and vegetation structure in tropical dry forests. In this study, we evaluated monthly, seasonal, and annual litterfall production over a five-year period in semideciduous dry forests of different successional ages growing on contrasting topographic conditions (sloping or flat terrain) in Yucatan, Mexico. Its relationship with climate and vegetation structural variables were also analyzed using multiple linear regression and generalized linear models. Litterfall was measured monthly in 12 litterfall traps of 0.5 m2 in three sampling clusters (sets of four 400 m2 sampling plots) established in forests of five successional age classes, 3–5, 10–17, 18–25, 60–79, and >80 years (in the latter two classes either on slopping or on flat terrain), for a total of 15 sampling clusters and 180 litterfall traps. Litterfall production varied between years (negatively correlated with precipitation), seasons (positively correlated with wind speed and maximum temperature), and months (negatively correlated with relative humidity) and was higher in flat than in sloping sites. Litterfall production also increased with successional age until 18–25 years after abandonment, when it attained values similar to those of mature forests. It was positively correlated with the aboveground biomass of deciduous species but negatively correlated with the basal area of evergreen species. Our results show a rapid recovery of litterfall production with successional age of these forests, which may increase with climate changes such as less precipitation, higher temperatures, and higher incidence of hurricanes.

Bryophyte relationships with environmental and structural variables in Tasmanian old-growth mixed eucalypt forest

2006 ◽  
Vol 54 (3) ◽  
pp. 239 ◽  
Author(s):  
P. A. M. Turner ◽  
J. B. Kirkpatrick ◽  
E. J. Pharo
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Canopy Cover ◽  
Basal Area ◽  
Mean Annual Temperature ◽  
Old Growth ◽  
Moss Species ◽  
Eucalypt Forest ◽  
Structural Variables ◽  
Negative Predictor

The species richness and species composition of bryophytes (mosses and liverworts) was recorded at 33 sites in Tasmanian old growth mixed eucalypt forest. A total of 202 bryophyte taxa were recorded, consisting of 115 liverworts and 87 mosses. This constitutes approximately one third of the total bryophyte flora for Tasmania. Mean liverwort species richness per site was higher than moss species richness. Latitude was found to be a positive predictor in all multiple regression models of bryophyte, moss and liverwort species richness. Mean annual temperature and rainfall of the driest month were positive predictors for bryophyte and liverwort species richness. Basal area of the treefern Dicksonia antarctica Labill. was a negative predictor of liverwort species richness. Latitude, variables relating to moisture, mean annual temperature, rainfall of the driest month and basal area of Dicksonia antarctica were the most significant components in predicting variation in bryophyte, moss and liverwort species composition. There were few relationships between the variables of canopy cover and soil nutrients and bryophyte species richness and composition. Substrate variables were found to be important components in predicting variation in moss and bryophyte species composition.

scholarly journals The influence of depth-to-groundwater on structure and productivity of Eucalyptus woodlands

2014 ◽  
Vol 62 (5) ◽  
pp. 428 ◽  
Author(s):  
Sepideh Zolfaghar ◽  
Randol Villalobos-Vega ◽  
James Cleverly ◽  
Melanie Zeppel ◽  
Rizwana Rumman ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Net Primary Productivity ◽  
Basal Area ◽  
Tree Height ◽  
Stem Density ◽  
Aboveground Net Primary Productivity ◽  
Area Index ◽  
Mean Values ◽  
Huber Value ◽  
Eastern Australia

Although it is well documented that access to groundwater can help plants survive drought in arid and semiarid areas, there have been few studies in mesic environments that have evaluated variation of vegetation characteristics across a naturally occurring gradient in depth-to-groundwater (DGW). The aim of this study was to determine whether differences in groundwater depth influence structural attributes and productivity of remnant woodlands in south-eastern Australia. The study area was located in the Kangaloon bore-field area of New South Wales, where DGW varies from 2.4 m to 37.5 m and rainfall is plentiful. We examined structural (leaf-area index, basal area, stem density, tree height, Huber value (HV) and aboveground biomass) and functional (aboveground net primary productivity (ANPP)) attributes of seven woodland sites differing in DGW. We also used ∂13C analysis of sapwood across six sites, along with observed non-linear changes in structural attributes, to infer groundwater use by trees. Significant differences in structural attributes and ANPP were observed across sites. The three shallowest sites with 2.4 m, 4.3 m and 5.5 m DWG had significantly larger aboveground biomass and ANPP than did the four deepest sites (DGW ≥9.8 m). Across all attributes (except HV in the summer, where the mean values were significantly larger at sites where DGW was 5.5 m or less and across the four deeper sites (DGW ≥9.8 m), there were no differences in these three structural traits, nor in ANPP. Despite finding no significant differences in HV across sites in the summer, in winter, the two deepest sites had a significantly larger HV than did the two shallowest sites. Significant increases in ∂13C of sapwood occurred across five of the six sites, consistent with increasing water-use efficiency as DGW increased, reflecting the declining availability of groundwater with increasing DGW. This study has demonstrated that even in a mesic environment, putative access to groundwater can have important impacts on structural and functional traits of trees and, consequently, on woodland productivity.

scholarly journals Diversity of longhorned beetles (Coleoptera: Cerambycidae) in the Caribbean region of Colombia: temporal variation between two fragments of tropical dry forest

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Kimberly García ◽  
Neis José Martínez ◽  
Juan Pablo Botero
Keyword(s):  
Temporal Variation ◽  
Tropical Dry Forest ◽  
Species Abundance ◽  
Canopy Cover ◽  
Dry Forest ◽  
Caribbean Region ◽  
True Diversity ◽  
Longhorned Beetles ◽  
The Caribbean ◽  
Spatio Temporal

Abstract: The tropical dry forest is under constant threat from many anthropic activities which are conducted indiscriminately, modifying the forest, and therefore, affecting species that are closely related to its phenology, such as longhorned beetles (Cerambycidae). The spatio-temporal variation of the cerambycid diversity in two fragments of tropical dry forest (Reserva Campesina la Montaña and La Flecha) in the Caribbean region of Colombia was analyzed. At each locality, four squared plots were delimited, and the beetles were collected with fruit traps, beating sheets and manual capture, and with light traps in the center. Five hundred eighty-seven specimens representing 128 species were collected, of which members of the tribe Ectenessini (Cerambycinae) were the most abundant. At the subfamily level, Cerambycinae was the most abundant (465 specimens) and diverse (73 species), followed by Lamiinae and Prioninae. The highest values of richness (110 species), abundance (428), biomass (21.18 g), and as well as the highest values of true diversity (1D= 73.44, 2D= 34.30) were found during the first precipitations. Regarding beta diversity, temporal variation was determined and mainly explained by a high percentage of turnover (> 70%). Lastly, the high diversity of Cerambycidae was associated with high values of relative humidity and canopy cover during the rainy season. This showed that the structure of the cerambycid community in the tropical dry forest of the Caribbean region of Colombia depends on these variables, which are closely related to precipitation.

scholarly journals COMPOSICIÓN VEGETAL, PREFERENCIAS ALIMENTICIAS Y ABUNDANCIA DE BIBLIDINAE (LEPIDOPTERA: NYMPHALIDAE) EN UN FRAGMENTO DE BOSQUE SECO TROPICAL EN EL DEPARTAMENTO DEL ATLÁNTICO, COLOMBIA

2015 ◽  
Vol 20 (3) ◽  
pp. 79-92 ◽  
Author(s):  
María Angélica VARGAS- ZAPATA ◽  
Carlos José BOOM- URUETA ◽  
Leidys Isabel SEÑA-RAMOS ◽  
Alba Lucia ECHEVERRY-IGLESIAS ◽  
Neis José MARTÍNEZ HERNÁNDEZ
Keyword(s):  
Woody Plants ◽  
Tropical Dry Forest ◽  
Basal Area ◽  
Dry Forest ◽  
Forest Fragment ◽  
Plant Composition ◽  
Components Analysis ◽  
Spatio Temporal ◽  
Determining Factor

<p>Se analizó la variación espacio-temporal de la abundancia de las mariposas de la subfamilia Biblidinae (Lepidoptera: Nymphalidae) en un fragmento de Bs-T en la Reserva Campesina La Montaña (RCM), Atlántico, Colombia; desde enero hasta agosto de 2011. Se marcaron cuatro puntos dentro del área de estudio, donde se ubicaron trampas Van Someren–Rydon cebadas con calamar en descomposición, fruta fermentada y con una mezcla de los anteriores cebos. Adicionalmente, se realizó una caracterización de la vegetación por punto, para lo cual se tomaron datos de diámetro a la altura del pecho (DAP), altura y tamaño de la copa para todas aquellas plantas leñosas con DAP mayor o igual a 2,5 cm. Se capturaron 76 individuos agrupados en seis especies y cuatro géneros; destacándose <em>Hamadryas februa</em> (Hübner) como la más dominante con 32 individuos. El mes de marzo presentó la mayor riqueza y abundancia (6 especies y 25 individuos) durantes las primeras lluvias en la zona. El punto 3 presentó los valores más altos de diversidad y abundancia de Biblidinae (5 especies y 37 individuos) y la mayor densidad de árboles (D= 0,28 individuos/m<sup>2</sup>). Se demuestra que la estructura de este grupo de mariposas presenta un patrón temporal y espacial en esta reserva. El análisis de componentes principales demostró que el área basal total (ABT) y la Densidad (D) de plantas leñosas, pueden considerarse como un factor determinante en la distribución y abundancia de las especies de la subfamilia Biblidinae en la RCM.</p><p align="center"><strong>Plant Composition, Feeding Preferences and Abundance of Biblidinae (Lepidoptera: Nymphalidae) in a Tropical Dry Forest Fragment in the Department of Atlántico, Colombia</strong></p><p>The abundance and spatio-temporal variation of butterflies of the Biblidinae subfamily (Lepidoptera: Nymphalidae) in a fragment of Tropical dry forest at the Reserva Campesina La Montaña (RCM), Atlántico, Colombia; from January until August 2011, was analyzed. Within the study area four points were marked; Van Someren-Rydon traps were placed.in each point using rotten squid, fermented fruit and a mixture of both as bait. In addition, a characterization of the vegetation by point was performed, taking data of the diameter to the breast height (DBH), height and size of treetop of all woody plants with a DBH greater than or equal to 2.5 cm. In total 76 butterfly individuals grouped in six species and four genera were captured; being <em>Hamadryas februa</em> (Hübner) the most dominant with 32 individuals. The greatest richness and abundance was recorded in March (6 species and 25 individuals), during the first rains in the study area. The point 3 presented the highest values of diversity and abundance (five species and 37 individuals) of Biblidinae and the higher density of trees (D= 0,28 individuals/m2). The structure of this butterflies group presents a spatio-temporal pattern in this reserve. The principal components analysis showed that the total basal area (ABT) and the density (D) of woody plants, can be considered a determining factor in the distribution and abundance of species of the subfamily Biblidinae at the RCM.</p>

Impact of Eidolon helvum on roost trees on UENR campus

2018 ◽  
Vol 2 (2) ◽  
pp. 44-50
Author(s):  
E. Danquah
Keyword(s):  
Tree Species ◽  
Diversity Index ◽  
Canopy Cover ◽  
Basal Area ◽  
Tree Height ◽  
Tectona Grandis ◽  
Tree Canopy ◽  
Species Diversity Index ◽  
Tree Canopy Cover ◽  
Occupied Zone

Four sample plots, each of size 20m by 20m were systematically distributed in two strata (i.e. two plots in bat-occupied zone andthe remaining two plots in bat-unoccupied zone, to serve as control units). Using six (20m × 20m) sample plots each, basal area,canopy, and heights of trees with DBH 1m were measured. Fourteen individual trees were recorded in the bat-unoccupied zone,resulting in only seven tree species. On the other hand, 16 tree species, corresponding to a total of 25 trees were recorded in thebat occupied zone. Albizia zygia, Antiaris toxicaria, Azadiractha indicia, Holarrhena floribunda, Morinda lucinda, and Sterculiatragacantha were common to both zones. The Shannon Wiener species diversity index was found to be higher (H1=1.92) in batoccupied zones and lower (H1=1.45) in bat-unoccupied zone. Estimates of tree basal area and tree height were much higherin bat occupied zones compared to bat-unoccupied zones. (Mann-Whitney U test: U = 573.0, p < 0.05), tree basal area (U= 674.0, p < 0.05), tree height (U = 632.0, p < 0.05) and tree canopy cover (U = 329.0, p < 0.05). Holarrhena floribunda(0.34 m2/h) and Ceiba pentandra (0.22m2/ha) contributed the largest basal area (32.94% of the total basal area) whilst Sennasiamea (0.01m2/ha) and Tectona grandis (0.01m2/ha) yielded the smallest basal area (1.17%). In general, bats seem to greatlypatronize areas with higher densities of tall trees than relatively open areas with shorter trees.

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