http://www.repositorio.uem.mz/handle258/63 2026-04-23T07:07:39Z 2026-04-23T07:07:39Z Uetimane Jr., Ernesto Jebrane, Mohamed Terziev, Nasko Daniel, Geoffrey http://www.repositorio.uem.mz/handle258/861 2024-03-18T09:28:46Z 2018-01-01T00:00:00Z

Title: Comparative wood anatomy and chemical composition of Millettia mossambicensis and Millettia stuhlmannii from Mozambique Authors: Uetimane Jr., Ernesto; Jebrane, Mohamed; Terziev, Nasko; Daniel, Geoffrey Abstract: The wood anatomy and chemistry of a relatively lesser used wood species, known in Mozambique as nsangala (Millettia mossambicensis J. B. Gillett), was compared to overexploited species jambire (Milletia stuhlmannii Taub.) to provide diagnostic features for safe discrimination. The anatomical results showed that both species shared several similarities such as intervessel pitting size range (8 μm to 11 μm), rays composed of only procumbent cells, fiber dimensions (average length up to 1359 μm and wall thickness up to 10 μm), and banded axial parenchyma. The extractives and lignin content were higher in jambire, while the carbohydrates and acetyl contents were higher in nsangala. The main anatomical feature separating the two species was the porosity pattern with semi-ring porous wood of nsangala compared to the diffuse-porous structure of jambire. Jambire had wider vessel lumina (200 μm) and up to 3 vessels/mm2 compared to nsangala vessel lumina of 86 μm and a frequency of 37 vessels/mm2.

2018-01-01T00:00:00Z Lisboa, Sá Nogueira Guedes, Benard Soares Ribeiro, Natasha Sitoe, Almeida A. http://www.repositorio.uem.mz/handle258/860 2024-03-18T09:30:03Z 2018-01-01T00:00:00Z

Title: Biomass allometric equation and expansion factor for a mountain Moist evergreen forest in Mozambique Authors: Lisboa, Sá Nogueira; Guedes, Benard Soares; Ribeiro, Natasha; Sitoe, Almeida A. Abstract: Worldwide, forests are an important carbon sink and thus are key to mitigate the effects of climate change. Mountain moist evergreen forests in Mozambique are threatened by agricultural expansion, uncontrolled logging, and firewood collection, thus compromising their role in carbon sequestration. There is lack of local tools for above-ground biomass (AGB) estimation of mountain moist evergreen forest, hence carbon emissions from deforestation and forest degradation are not adequately known. This study aimed to develop biomass allometric equations (BAE) and biomass expansion factor (BEF) for the estimation of total above-ground carbon stock in mountain moist evergreen forest. The destructive method was used, whereby 39 trees were felled and measured for diameter at breast height (DBH), total height and the commercial height. We determined the wood basic density, the total dry weight and merchantable timber volume by Smalian’s formula. Six biomass allometric models were fitted using non-linear least square regression. The BEF was determined based on the relationship between bole stem dry weight and total dry weight of the tree. To estimate the mean AGB of the forest, a forest inventory was conducted using 27 temporary square plots. The applicability of Marzoli’s volume equation was compared with Smalian’s volume equation in order to check whether Marzoli’s volume from national forest inventory can be used to predict AGB using BEF. The best model was the power model with only DBH as predictor variable, which provided an estimated mean AGB of 291 ± 141 Mg ha−1 (mean ± 95% confidence level). The mean wood basic density of sampled trees was 0.715 ± 0.182 g cm−3. The average BEF was of 2.05 ± 0.15 and the estimated mean AGB of 387 ± 126 Mg ha−1. The BAE from miombo woodland within the vicinity of the study area underestimates the AGB for all sampled trees. Chave et al.’s pantropical equation of moist forest did not fit to the Moribane Forest Reserve, while Brown’s equation of moist forest had a good fit to the Moribane Forest Reserve, having generated 1.2% of bias, very close to that generated by the selected model of this study. BEF showed to be reliable when combined with stand mean volume from Marzoli’s National Forestry Inventory equation. The BAE and the BEF function developed in this study can be used to estimate the AGB of the mountain moist evergreen forests at Moribane Forest Reserve in Mozambique. However, the use of the biomass allometric model should be preferable when DBH information is available.

2018-01-01T00:00:00Z Magalhães, Tarquinio Mateus Mate, Rosta Simão http://www.repositorio.uem.mz/handle258/859 2024-03-18T09:32:11Z 2018-01-01T00:00:00Z

Title: Least Squares-Based biomass conversion and expansion factors best estimate biomass than ratio-based ones: statistical evidences based on tropical timber species Authors: Magalhães, Tarquinio Mateus; Mate, Rosta Simão Abstract: Due to its readiness to convert stem volumes (V) into biomass, national and regional aboveground biomass estimates and greenhouse gas reporting are generally based on biomass conversion and expansion factors (BCEFs). BCEF-based biomass (W) is computed by the following regression through the origin (RTO): W?=?BCEF?×?V. However, the regression slope (BCEF) is not obtained using least squares (LS); it is obtained as the ratio of observed biomass and stem volume. Therefore, the sum of squares of the residuals is not minimum. This may lead to strongly biased biomass estimates. Furthermore, in this case, the biomass is not modelled. In the present study, it was suggested that BCEFs should be obtained using LS through RTO. The objective of this study was to compare LS-based and ratio-based BCEFs with regard to predictive accuracy and ability. A dataset of 75 trees from 4 species was used for the comparisons. LS-based BCEFs were associated with higher predictive accuracy and ability than ratio-based ones. It was proved that RTO is appropriated for estimating BCEFs, as the intercept a was consistently not significant. Ratio-based BCEFs may lead to seriously biased biomass and carbon stocks estimates. BCEFs should be estimated using least squares.

2018-01-01T00:00:00Z Pockrandt, Michael Jebrane, Mohamed Cuccui, Ignazia Allegretti, Ottaviano Uetimane Jr, Ernesto http://www.repositorio.uem.mz/handle258/858 2024-03-18T09:33:06Z 2018-01-01T00:00:00Z

Title: Industrial Thermowood® and Termovuoto thermal modification of two hardwoods from Mozambique Authors: Pockrandt, Michael; Jebrane, Mohamed; Cuccui, Ignazia; Allegretti, Ottaviano; Uetimane Jr, Ernesto Abstract: The study aimed at treating metil (Sterculia appendiculata K. Schum) and neem (Azadirachta indica A. Juss) timber from Mozambique under industrial condi- tions by steam [Thermowood® (TW)] and vacuum [Termo- vuoto (TV)] thermal modifications (TM). Matched boards were treated identically and wood alterations in chem- istry, colour, mass loss (ML), mechanical properties and durability were compared. The applied vacuum partly removed the acetic acid that causes carbohydrate degra- dation, i.e. heat applied under vacuum was less destruc- tive. TM under vacuum generated a lighter colour than that caused by steam treatment. ML was significantly higher after the TW process namely, 14.1 vs. 9.9% after thermo- vacuum treatment for metil and 14.2 and 12.1% for neem. Colour and ML changes correlated with the decrease in shear strength, rupture and elasticity moduli and increase in wood decay resistance. Metil wood is more permeable and demonstrated significant differences between the treatments; the thermo- vacuum process was less destruc- tive but led to less improvement of durability compared to TW treatment.

2018-01-01T00:00:00Z