Woody Species Structure and Regeneration Status in Kafta Sheraro National Park Dry Forest, Tigray Region, Ethiopia

The study was conducted in Kafta Sheraro National Park (KSNP) dry woodland natural forest located in Kafta Humera and Tahitay Adiyabo weredas (districts), Western and Northwestern Zones of Tigray regional governmental state, North Ethiopia. The objective of the study was to explore the floristic composition, structure, and regeneration of woody species in the home of Loxodonta africana L., Hippotragus equinus, Anthropoides virgo, Ourebia ourebi, Crocuta crocuta, Tragelaphus strepsiceros, Phacochoerus africanus, and unidentified crocodile and fish species. In the park, the vegetation ecology has not been studied up to date which is necessary for conservation. The systematic sampling technique was used to collect vegetation and human disturbance (presence and absence) data from August to December 2018. The vegetation data were collected from 161 plots each with a size of 400 m2 (20 m × 20 m) for tree/shrub while subplots of size 100 m2 (10 m × 10 m) and 25 m2 (5 m × 5 m) for sapling and seedling, respectively, were established in the main plots. Individual tree and shrub diameter at breast height (DBH) ≥2.5 cm and height ≥ 2 m were measured using tape meter and clinometer, respectively. Diameter at breast height (DBH), frequency, density, basal area, and importance value index (IVI) were used for vegetation structure description while the density of mature trees, sapling, and seedling was used for regeneration. A total of 70 woody species (46 (65.7%) trees, 18 (25.7%) shrubs, and 6 (8.6%) tree/shrub) were identified. The total basal area and density of 79.3 ± 4.6 m2·ha−1 and 466 ± 12.8 stems·ha−1, respectively, were calculated for 64 woody species. Fabaceae was the most dominant family with 16 species (22.9%) followed by Combretaceae with 8 species (11.4%). The most dominant and frequent species throughout the park were Acacia mellifera, Combretum hartmannianum, Terminalia brownii, Balanites aegyptiaca, Dichrostachys cinerea, Acacia senegal, Acacia oerfota, Boswellia papyrifera, Ziziphus spina-christi, and Anogeissus leiocarpus. Abnormal patterns of selected woody species were dominantly identified. The regenerating status of all the woody plant species was categorized as “fair” (18.75%), “poor” (7.81%), and “none” (73.44%). There was a significant correlation between altitude, anthropogenic disturbance (grazing and fire frequency), and density of seedling, sapling, and mature trees. But there was no correlation between gold mining and regeneration population. However, there is a good initiation for the conservation of the park; still, the vegetation of the park was threatened by human-induced fire following intensive farming, gold mining, and overgrazing. Therefore, the study area was the habitat for the population of the African elephant; species with low importance value indices and lack or having few seedling and sapling stage should be prioritized for conservation, and their soil seed banks should be studied further.

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Woody Species Diversity and Structure of Protected Woodlands Adjacent to Free Grazing Land Woodland at Dugda Woreda, Oromia, Ethiopia

International Journal of Forestry Research ◽

10.1155/2021/8834892 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Tsegu Ereso Denbel

Keyword(s):

Basal Area ◽

Floristic Composition ◽

Woody Species ◽

Systematic Sampling ◽

Importance Value Index ◽

Importance Value ◽

Mature Trees ◽

Grazing Land ◽

Individual Tree ◽

Breast Height

The study was conducted in protected woodland and free graze woodland located in Dugda Woreda, Oromia state, Ethiopia. The objective of the study was to explore the floristic composition, structure, and regeneration of woody species. In the park, the vegetation ecology has not been studied up to date, which is necessary for conservation. The systematic sampling technique was used to collect vegetation and human disturbance (presence and absence) data from August to December 2017. The vegetation data were collected from 30 plots from each woodland with a size of 900 m2 (30 m × 300 m) for tree/shrub, while subplots of size 400 m2 (20 m × 20 m) for sapling, respectively, were established in the main plots. Individual tree and shrub diameters at breast height (DBH) ≥2.5 cm and height ≥ 2 m were measured using a tape meter and clinometer, respectively. Diameter at breast height (DBH), frequency, density, basal area, and importance value index (IVI) were used for vegetation structure description, while the densities of mature trees, sapling, and seedling were used for regeneration. A total of 446 individual stems from free grazed woodland and 641 individual stems from protected woodland with a DBH of ≥2.5 cm were encountered from 30 studied sample plots that are protected and free grazed woodlands. Of these, from the total woody species, 68.42% were trees and 31.57% shrubs found in protected woodland; 76.92% were trees and 23.07% shrubs found in free grazed woodland. The total basal area of the woody plant was 3.1 ± 1 m2/ha in free grazed woodland and 4.2 ± 2 m2/ha in protected woodland, calculated for 19 woody species. Fabaceae, Balanitaceae, Capparidaceae, Verbenaceae, and Boraginaceae families were the most abundant families in both woodlands. However, there is a good initiation for the conservation of the park; still, the vegetation of the park was threatened by human-induced fire following intensive farming, gold mining, and overgrazing.

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Modeling of aboveground tree stand-level biomass in Erukot Forest of Oban Division, Cross River National Park, Nigeria

Journal of Agriculture Forestry and the Social Sciences ◽

10.4314/joafss.v18i1.2 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

S.E. Bassey ◽

S. Ajayi

Keyword(s):

Carbon Dioxide ◽

Aboveground Biomass ◽

National Park ◽

Basal Area ◽

Tree Stand ◽

Diameter At Breast Height ◽

Total Height ◽

Breast Height ◽

Dry Biomass ◽

Individual Trees

This research estimated aboveground tree stand level Biomass in Erukot Forest of Oban Division, Cross River National Park. A total of 872 individual trees were identified and measured for diameter at breast height and total height (dbh ≥ 5cm). The 872 individual trees spread across 51 species belonging to 25 different tree families. Simple random sampling was used with sampling intensity of 0.3% to lay 15 nested plots (7m x 7m, 25m x 25m and 35m x 35m). Diameter at breast height, total height and specific density of each wood species were used to determine aboveground biomass for each tree. Conversion factors were applied to estimate stand level green and dry biomass, sequestered carbon and carbon dioxide (CO2) emission in the study area. Simple linear regression models were fitted into the stand level growth data for the forest (basal area and volume). The mean diameter at breast height and mean total height were 38.5cm and 18.5m respectively. Mean basal area of 39.8 m2 ha-1 was obtained with a mean volume of 177.3 m3 ha-1 . Average green biomass, dry biomass, carbon stock and carbon-dioxide emission of 521.8113 ton ha-1 , 341.5880 ton ha-1 , 183.196 ton ha-1 and 694.2067 ton ha-1 respectively were obtained in the study area. Stand level biomass model developed for the forest showed that common logarithm of volume per hectare is significantly related to common logarithm of stand biomass (R2 = 58%). The actual and predicted biomasses were not significantly different (Paired T-test at p ˂ 0.05). Estimated bias of 0.10% for the stand biomass model means that the developed model can be used to predict the aboveground biomass of the study area without any adjustment. The research has provided easy to use regression model for determining aboveground biomass at stand level. This is very useful for carbon trade and assessment of carbon-dioxide emissions through deforestation in the study area. The model is also a tool for assessing the wood productivity of the study area and for better management of the park. Keyword: Sequestered carbon, aboveground biomass, dry biomass, conversion factor

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Modelling survival probability of individual trees in Norway spruce stands under different thinning regimes

Canadian Journal of Forest Research ◽

10.1139/x04-161 ◽

2005 ◽

Vol 35 (1) ◽

pp. 113-121 ◽

Cited By ~ 11

Author(s):

Kjell Karlsson ◽

Lennart Norell

Keyword(s):

Norway Spruce ◽

Goodness Of Fit ◽

Basal Area ◽

Site Index ◽

Stand Age ◽

Goodness Of Fit Test ◽

Individual Tree ◽

Thinning Intensity ◽

Diameter At Breast Height ◽

Breast Height

The probability that an individual tree will remain in even-aged Norway spruce (Picea abies (L.) Karst.) stands subjected to different thinning programmes was modelled, using data from a thinning experiment established in 25 localities in southern Sweden. A logistic regression approach was used to predict the probability and the HosmerLemeshow goodness-of-fit test to evaluate the fit. Diameter at breast height (DBH), quadratic mean DBH, thinning intensity, thinning quotient, basal area, number of stems per hectare, stand age, number of thinnings, and site index were used as explanatory variables. Separate analyses for stands thinned from below, stands thinned from above, and unthinned stands were performed. The modelled probability graphs for trees not being removed, plotted against their diameter at breast height, had clear S-shapes for both unthinned stands and stands thinned from below. The graph for stands thinned from above was bell-shaped.

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Floristic Structure of Fire Experimental Plots of Olokemeji Forest Reserve, Ogun State, Nigeria

Journal of Applied Sciences and Environmental Management ◽

10.4314/jasem.v24i11.3 ◽

2020 ◽

Vol 24 (11) ◽

pp. 1861-1865

Author(s):

DM Taiwo ◽

OR Olatidoye ◽

OR Jeminiwa ◽

TO Oyebola ◽

C Omonu

Keyword(s):

Tree Species ◽

Basal Area ◽

Relative Importance ◽

Importance Value ◽

Forest Reserve ◽

Diameter At Breast Height ◽

Breast Height ◽

Ogun State ◽

Mean Diameter ◽

Floristic Structure

Total enumeration of tree species was carried out fire experimental plot of Olokemeji forest reserve for relative importance value (RIV) mean heights, mean diameter at breast height and mean basal area. Three investigative plot (Plot A, B and C) were established. Plot A which represents Early Burn is burnt annually during the dry season while Plot B was burnt annually during the rainy season when the trees are still wet and Plot C serves as the protected area. Gmelina arborea had the highest relative importance value (28.31), this is followed by Dalbergia sissoo which had RIV of 10.94. Plot C recorded the highest frequency of trees with the highest tree heights, this is closely followed by Plot A and Plot B being the plot with the lowest mean height. Plot C has the highest mean diameter at breast height (DBH) of trees and it is followed by Plot B and Plot A with very close mean DBH. The highest mean basal area was also recorded in Plot C, the highest total basal area and tree volume was also recorded at Plot C as 32.2 m2 ha-1 and 188.8 m3. The size distribution of tree species depicts that Plot C has been protected just as expected Keywords: Forest, Structure, Flora, Dynamics, Fire

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An individual-tree linear mixed-effects model for predicting the basal area increment of major forest species in Southern Europe

Forest Systems ◽

10.5424/fs/2020293-15500 ◽

2020 ◽

Vol 29 (3) ◽

pp. e019

Author(s):

Lucio Di Cosmo ◽

Diego Giuliani ◽

Maria Michela Dickson ◽

Patrizia Gasparini

Keyword(s):

Forest Inventory ◽

Basal Area ◽

Ordinary Least Squares ◽

Mixed Effects ◽

Forest Growth ◽

Mixed Effects Model ◽

Basal Area Increment ◽

Individual Tree ◽

Diameter At Breast Height ◽

Breast Height

Aims of the study. Assessment of growth is essential to support sustainability of forest management and forest policies. The objective of the study was to develop a species-specific model to predict the annual increment of tree basal area through variables recorded by forest surveys, to assess forest growth directly or in the context of more complex forest growth and yield simulation models.Area of the study. Italy.Material and methods. Data on 34638 trees of 31 different forest species collected in 5162 plots of the Italian National Forest Inventory were used; the data were recorded between 2004 and 2006. To account for the hierarchical structure of the data due to trees nested within plots, a two-level mixed-effects modelling approach was used.Main results. The final result is an individual-tree linear mixed-effects model with species as dummy variables. Tree size is the main predictor, but the model also integrates geographical and topographic predictors and includes competition. The model fitting is good (McFadden’s Pseudo-R2 0.536), and the variance of the random effect at the plot level is significant (intra-class correlation coefficient 0.512). Compared to the ordinary least squares regression, the mixed-effects model allowed reducing the mean absolute error of estimates in the plots by 64.5% in average.Research highlights. A single tree-level model for predicting the basal area increment of different species was developed using forest inventory data. The data used for the modelling cover 31 species and a great variety of growing conditions, and the model seems suitable to be applied in the wider context of Southern Europe. Keywords: Tree growth; forest growth modelling; forest inventory; hierarchical data structure; Italy.Abbreviations used: BA - basal area; BAI – five-year periodic basal area increment; BALT - basal area of trees larger than the subject tree; BASPratio - ratio of subject tree species basal area to stand basal area; BASTratio - ratio of subject tree basal area to stand basal area; CRATIO - crown ratio; DBH – diameter at breast height ; DBH0– diameter at breast height corresponding to five years before the survey year; DBHt– diameter at breast height measured in the survey year; DI5 - five-year, inside bark, DBH increment; HDOM - dominant height; LULUCF - Land Use, Land Use Changes and Forestry; ME - mean error; MAE - mean absolute error; MPD - mean percent deviation; MPSE - mean percent standard error; NFI(s) - National Forest Inventory/ies; OLS - ordinary least squares regression; RMSE - root mean squared error; UNFCCC - United Nation Framework Convention on Climate Change.

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The impact of intraspecific competition on tree growth in planted Korean pine forest

TAP CHI SINH HOC ◽

10.15625/0866-7160/v42n1.14435 ◽

2020 ◽

Vol 42 (1) ◽

Author(s):

Nguyen Thanh Tuan ◽

Vu Dinh Duy ◽

Shen H-L

Keyword(s):

Tree Growth ◽

Basal Area ◽

Individual Growth ◽

Korean Pine ◽

Competition Intensity ◽

Individual Tree ◽

Diameter At Breast Height ◽

Breast Height ◽

Crown Width ◽

Individual Tree Growth

The aim of this study was to explore the correlation of competition indices (CIs) on individual tree growth for Korean pine (Pinus koraiensis) plantation using partial correlation analysis and generalized linear models. The data were collected from 15 permanent plots in Mengjiagang forestry farm, Northeast China. The results showed that the distance dependent CIs have a higher predictive capacity for individual growth of pine trees. The control index of competitive trees number (CI1) combined with the selection fixed competitor trees (M2) was found to be the most well correlated competition measure with five - years diameter increment. Thus, the competition index (CI1- M2) was recommended for developing individual tree growth models. The subject tree diameter at breast height, crown width, height to crown base, tree volume and basal area all showed a significantly linear correlation with tree competition intensity (P < 0,05). Diameter at breast height, crown width, tree volume and basal area all decreased with increasing competition intensity, whereas the height to crown base increased. There was no significant relationship between competition intensity and tree height (P > 0,05). The optimal model of predicting individual growth with logarithm of diameter at breast height and CIs as the independent variables due to the best fitting performance. This results also showed considerable improvement in predicting individual tree periodic growth when including competition indices that the mean absolute error is reduced in the range of 22−25%.

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Using tree rings to assess the potential of thinning to alleviate drought stress in a dry forest of western Canada

10.5194/egusphere-egu21-13182 ◽

2021 ◽

Author(s):

David Montwé ◽

Audrey Standish ◽

Miriam Isaac-Renton ◽

Jodi Axelson

Keyword(s):

Tree Ring ◽

Tree Rings ◽

Basal Area ◽

Dry Forest ◽

Tree Level ◽

Severe Drought ◽

Western Canada ◽

Drought Event ◽

Individual Tree ◽

Potential Benefits

Increasing frequency of severe drought events under climate change is a major cause for concern for millions of hectares of forested land. One practical solution to improving forest resilience may be thinning. There may be several potential benefits, chief of which is that drought tolerance could be improved in the remaining trees due to lower competition for resources and increased precipitation throughfall. By improving resilience to drought, this may increase productivity of the remaining trees while lowering risks of mortality. Such potential benefits can effectively be quantified with data from statistically-sound, long-term field experiments, and tree rings provide a suitable avenue to compare treatments. We work with an experiment that applied different levels of tree retention to mature interior Douglas fir (Pseudotsuga menziesii var. glauca) in a dry ecosystem of western Canada. The treatments were applied in the winter of 2002/2003, coinciding with the aftermath of a severe natural drought event in 2002. We used tree-rings to quantify the extent to which thinning improves recovery and resilience of treated trees as compared to non-thinned controls. Tree-ring samples as well as height and diameter data were obtained from 83 trees from 8 treatment units of the randomized experimental design. Indicators for resilience to drought were calculated based on basal area increments. Thinning substantially increased basal area increments at the individual tree level, but more importantly, led to significantly higher recovery and resilience relative to the control. The results of this tree-ring analysis suggest that thinning may be a viable silvicultural intervention to counteract effects of severe drought events and to maintain tree cover.

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Dynamics of Forest Clumps on Chenier Plains, Cobourg Peninsula, Northern Territory

Australian Journal of Botany ◽

10.1071/bt9900593 ◽

1990 ◽

Vol 38 (6) ◽

pp. 593 ◽

Cited By ~ 15

Author(s):

DMJS Bowman ◽

WJ Panton ◽

L Mcdonough

Keyword(s):

National Park ◽

Field Experiments ◽

Calcareous Soils ◽

Basal Area ◽

Woody Species ◽

Acacia Auriculiformis ◽

Tree Crown ◽

Bos Javanicus ◽

Preferred Habitat ◽

Monsoon Forest

Forest clumps occur scattered throughout Sorghum plumosum grasslands on chenier plains at Gurig National Park, Cobourg Peninsula, a preferred habitat for the introduced banteng (Bos javanicus.). The clumps are dominated by Pandanus spiralis, Acacia auriculiformis, Alstonia actinophylla, Timonius timon and Casuarina equisetifolia and vary in size from the radius of one tree crown to large patches of over several hectares. Fifteen of the 32 woody species recorded in 42 clumps occurred as juveniles less than 1 cm diameter at breast height. Both the clumps and grasslands occur on uniform calcareous soils. The clumps are thought to be a stage in a succession towards monsoon forest. Field experiments showed that seedlings from a range of monsoon forest and savanna species can grow on the plains. Interpretation of aerial photography taken in 1963 and 1982 suggests that the clumps have expanded. Fire is thought to control the succession. A fire on the plains was found to kill between one and two-thirds of the basal area of Pandanus spiralis and A. auriculiformis and stimulated the establishment of six times more A. auriculiformis seedlings than in nearby unburnt clumps. Monsoon forest juveniles that invade the clumps typically resprout following fire. Stunted, fire-damaged monsoon forest species (e.g. Timonius timon, Alstonia actinophylla) occur in low densities in the grasslands. It is unclear whether banteng promotes the succession by reducing fuel loads in the grasslands and spreading A. auriculiforms seeds.

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Population status of the tree Sacoglottis holdridgei (Humiriaceae) at Isla del Coco National Park, Costa Rica

Revista de Biología Tropical ◽

10.15517/rbt.v64i1.23455 ◽

2016 ◽

Vol 64 (1) ◽

pp. 263

Author(s):

Luis Guillermo Acosta-Vargas

Keyword(s):

National Park ◽

Basal Area ◽

Forest Monitoring ◽

Diameter Distribution ◽

Population Status ◽

Importance Value Index ◽

Importance Value ◽

Data Points ◽

Using Data ◽

Annual Mortality

Isla del Coco is the only oceanic island in the Eastern Pacific with humid tropical climate. Its forests have a particular structure with a unique array of plant species and high endemism. There are few studies on the flora or forest monitoring on the island. The population structure of Sacoglottis holdridgei was analyzed using data from six years with data points taken in 2006 and 2012, including sampling of regeneration in 2012. Sacoglottis holdridgei was the most important tree species, presenting in 2012 the highest Importance Value Index (190.7±21.8), abundance (158.5±40.3 Nha-1 or 39.5 % of the forest) and basal area (15.6 m2ha-1 or 72.9 % of the forest). It was present in all three height strata with dominance in the highest. Annual mortality was reported at 3.3 % and recruitment at 1.2 %. The diameter distribution of forest fits the inverted J model, but not for the reported species of which only S. holdridgei tends to adjust for DBH>40 cm. Regeneration fitted the inverted J model with values below those reported for continental forests. Even though it was the dominant species, S. holdridgei showed low regeneration values. This particular condition, give way hypotheses related to the introduction of species, species biology and climate change which could influence the future development of S. holdridgei and forests of Isla del Coco.<div> </div>

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Biogenic Imprint on Hillslopes in the Sudety Mts. — Origin and Consequences of the Tree Uprooting Process

Studia Geomorphologica Carpatho-Balcanica ◽

10.1515/sgcb-2015-0002 ◽

2014 ◽

Vol 48 (1) ◽

Author(s):

Łukasz Pawlik

Keyword(s):

National Park ◽

Qualitative Description ◽

Main Subject ◽

Diameter At Breast Height ◽

Geomorphological Mapping ◽

Breast Height ◽

The World ◽

The Mean ◽

Tree Uprooting ◽

Root Plate

AbstractThe main subject of this article is the tree uprooting process and its effects on forested hillslopes in the Sudety Mts. The research has been carried out between 2010 and 2012 in the Karkonosze National Park (KNP), Stołowe Mountains National Park (SMNP) and Suche Mts. The methods included: detailed geomorphological mapping and measurements of root plates of recently fallen trees and relict treethrow mounds and pits (called pit-and-mound microtopography), their qualitative description and measurements of diameter at breast height (dbh) of uprooted tree trunks.The mean root plate volume was 0.3-1.4 mIt has been shown that tree uprooting can contribute to the evolution of regolith and soils and it is an important factor of their disturbances. This reflects results from other sites in the World. However, in the Sudety Mts. the significance of tree uprooting has been validated only locally and it is suggested that its importance decreases proportionally to the area under consideration. Here, biogenic transport is limited to treethrow pits on gentle hillslopes but can be much more effective at steeper sites.

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