Southern Forests: a Journal of Forest Science 2024-01-23T07:00:18+00:00 Publishing Manager Open Journal Systems <p><em>Southern Forests: a Journal of Forest Science</em>&nbsp;is one of the leading forestry journals in the Southern Hemisphere. The journal publishes scientific articles in forest science and management of fast-growing, planted or natural forests in the Southern Hemisphere and the tropics. Papers are also encouraged on related disciplines such as environmental aspects of forestry, social forestry, agroforestry, forest engineering and management as well as the goods and services that are derived from forests as a whole. Articles published by the journal are of value to foresters, resource managers and society at large. The journal particularly encourages contributions from South America, Africa and tropical/subtropical Australasia and Asia. Publication of the journal is supported by the Southern African Institute of Forestry.</p> <p>Read more about this journal <a href="" target="_blank" rel="noopener">here</a>.&nbsp;</p> Tree diversity, vegetation structure and management of mangrove systems on Viti Levu, Fiji Islands 2024-01-23T06:09:18+00:00 Ashik Rubaiyat Nicholas Rollings Stephen Galvin Ralph Mitloehner Sohag Miah Hans Juergen Boehmer <p><strong>Mangrove forest ecosystems are critical natural resources, particularly in the South Pacific region. Mangrove forests in Viti Levu, Fiji’s main island, are threatened by infrastructure development activities and population growth. Consequently, the protection and restoration of mangrove forest are of utmost importance. This study investigated the diversity and structure of mangrove forest on Viti Levu to determine the most appropriate species for use in restoration projects. These species could enhance the management of mangroves in Fiji. Five sites were selected: Ellington Wharf (EW), Naboutini Village (NV), Nasese (NA), Suva City Council Park (SCCP) and the University of the South Pacific Upper Campus (UUC). The variations in the number of tree stumps from site-to-site highlighted differences in the degree of anthropogenic disturbances, EW was classified as an undisturbed site while NA was highly disturbed. The sites were examined using systematic line transects with random starting points. Continuous belt transects were established, along which 10 m × 10 m segments were selected as the primary plots (</strong><strong><em>n </em></strong><strong>= 100 primary plots). Tree species, stand structure, tree diameter and height, stem abundance, stand volume, basal area and natural regeneration were recorded at all sites. Five mangrove species (</strong><strong><em>Rhizophora stylosa </em></strong><strong>Griff., </strong><strong><em>Bruguiera gymnorhiza </em></strong><strong>(L.) Lam., </strong><strong><em>Excoecaria agallocha </em></strong><strong>(L.), </strong><strong><em>Rhizophora samoensis </em></strong><strong>(Hochr.) Salvoza, and </strong><strong><em>Rhizophora × selala </em></strong><strong>(Salvoza) Toml.) were identified. The species importance value indices were highest for </strong><strong><em>R. stylosa </em></strong><strong>at EW (264.0) and for </strong><strong><em>B. gymnorhiza</em></strong><strong>) at NV (175.2). All sites had at least some level of human disturbance but </strong><strong><em>R. stylosa </em></strong><strong>and </strong><strong><em>B. gymnorhiza </em></strong><strong>thrived regardless of the extent of anthropogenic impacts. Subsequently, </strong><strong><em>R. stylosa </em></strong><strong>and </strong><strong><em>B. gymnorhiza </em></strong><strong>are recommended for mangrove forest ecosystem restoration programmes in Fiji.</strong></p> 2024-01-23T00:00:00+00:00 Copyright (c) 2024 Woody biomass increases across three contrasting land uses in Hurungwe, mid-Zambezi valley, Zimbabwe 2024-01-23T06:19:14+00:00 Tatenda Gotore Sam Bowers Hilton GT Ndagurwa Shakkie Kativu Anderson Muchawona Pomerayi Mutete Mduduzi Tembani Ruramai Murepa Admore Mureva Casey Ryan Denis Gautier Laurent Gazull <p><strong>Globally, Miombo woodlands store important quantities of carbon, with tree cover and carbon stocks strongly determined by human use. We assessed woodland cover and aboveground carbon (AGC) stocks of miombo along a utilisation gradient on three different land use types, that is, a national park, a buffer zone and a communal area. Woodland cover and carbon stock changes were assessed through mapping of AGC between 2007 and 2017 using Phased Array L-Band Synthetic Aperture Radar observations (ALOS-PALSAR 1 and 2). Woodland cover was higher in the national park and the buffer zone than in the communal area for both 2007 and 2017. In 2007, mean AGC stock was not significantly different (</strong><strong><em>p </em></strong><strong>= 0.05) across all three land use types. However, in 2017, mean AGC was significantly lower (</strong><strong><em>p </em></strong><strong>&lt; 0.001) in the buffer zone and communal area than in the national park. In all three land use types, Miombo woodland cover and mean AGC gains outweighed losses over the 10-year period. AGC gains were significantly higher (</strong><strong><em>p </em></strong><strong>&lt; 0.001) in the national park than in both the buffer zone and the communal area. Results of the study indicate that woodland cover and aboveground carbon increased in all three land use types despite the observed human disturbance over the study period. Both variables recorded a lower increase with elevated utilisation. The study concluded that sustainable resource utilisation is possible without loss of such ecosystem services as carbon sequestration and climate change mitigation.</strong></p> 2024-01-23T00:00:00+00:00 Copyright (c) 2024 Secondary vegetation provides a reservoir of non-timber forest products and agroforestry service options for forestry plantation systems, Maputaland, South Africa 2024-01-23T06:28:33+00:00 AP Starke CJ Geldenhuys TG O'Connor CS Everson <p><strong>Tree species providing non-timber forest products (NTFPs) have the potential to enhance the socio-economic value of forestry plantation systems and mitigate biodiversity loss associated with production landscapes in Southern Africa. This can be accomplished by integrating NTFP agroforestry systems with forestry plantation systems but raises questions around which species and products are suited to the different environments that exist within large plantation systems or plantation landscapes. These questions can be answered by assessing the NTFP and agroforestry system (AFS) value of native species that form part of secondary vegetation within forestry plantations by shedding light on the disturbance regimes and environmental conditions that NTFP species prefer. This study assessed the NTFP value of secondary vegetation growing within abandoned clear-felled and abandoned unharvested forestry compartments. It addressed differences between the NTFP value of secondary vegetation and natural forest while providing options for how native species could be integrated into a forestry plantation system using agroforestry. We found that secondary vegetation growing in abandoned compartments provided roughly two-thirds of the NTFP uses provided by natural forest. The state of the compartment at the time of abandonment influenced which NTFPs were available. Secondary woodland developing in clear-felled compartments contained NTFPs which were associated with fire-adapted woodland species (e.g. fruit and oils from Marula trees). Naturalising forest in unfelled plantation compartments contained a composition of NTFPs associated with the provision of wood products. Our results show that native vegetation growing as secondary vegetation in forestry plantation systems has the potential to guide the development of native species agroforestry systems and, in general, can contribute to a more formalised approach for integrating NTFP supply in forestry plantation systems.</strong></p> 2024-01-23T00:00:00+00:00 Copyright (c) 2024 Effects of thinning on growth performance of teak (<i>Tectona grandis</i>) plantations in Tain II Forest Reserve, Ghana 2024-01-23T06:33:17+00:00 Bertrand Festus Nero Maxwell Asuenabisa <p><strong>Although recent interest in commercial teak plantation establishment has soared, knowledge of intensive silvicultural management of residual stands is limited in most parts of West Africa. This study evaluated the effects of thinning regimes on the growth responses and pruning requirements of teak plantations, two years after thinning, in the transition zone of Ghana. The thinning trial was conducted on a 4-year-old stand with initial stocking of 1 111 trees ha<sup>−1</sup></strong> <strong>in the Tain II Forest Reserve, Ghana. The treatments were four thinning regimes: 50%, 30%, 0% thinning intensities and 50% decrowning, arranged in a completely randomised design with four replicates. Two years after thinning, the treatments were significantly different in diameter at breast height (DBH) (</strong><strong><em>p </em></strong><strong>&lt; 0.00029), total height (</strong><strong><em>p </em></strong><strong>= 0.017) and stem density (</strong><strong><em>p </em></strong><strong>&lt; 0.0002). The 50% thinning intensity had the highest mean tree DBH, volume, height and basal area of 15.57 cm, 0.13 m<sup>3</sup>, 11.94 m and 0.02 m<sup>2</sup></strong> <strong>respectively. The lowest was found in the control (no thinning) except height which was least in decrowned plots. Maximum mean annual increment of DBH, total height and volume were respectively 2.00 cm, 1.34 m and 9.9 m<sup>3</sup></strong> <strong>ha<sup>−1</sup></strong> <strong>for the heavily thinned stand. The number of epicormic shoots per tree increased with the thinning intensity/regime, hence increasing the pruning requirement. It is concluded that 50% thinning intensity promotes positive growth of residual stand but increases the pruning requirements and possibly the pruning costs. Long-term evaluation of this trial is essential to validate the recommendations from this study.</strong></p> 2024-01-23T00:00:00+00:00 Copyright (c) 2024 Genetic variability of <i>Tachigali vulgaris</i> trees based on seed morphophysiological traits 2024-01-23T06:37:13+00:00 Noemi Vianna Martins Leão Sérgio Heitor Sousa Felipe Ricardo Gallo Elizabeth Santos Cordeiro Shimizu <p><strong><em>Tachigali vulgaris </em></strong><strong>is a tree with high potential for energy purposes in Brazil. However, there is little information about genetic variability that can be applied to plant breeding. Here, we quantified genetic variability based on biometric and emergence traits of </strong><strong><em>T. vulgaris </em></strong><strong>seeds from the native population of the Brazilian Amazon. The biometric aspects, moisture content, emergence, emergence speed index, and average emergence time of the seeds were evaluated. Genotypic values and genetic parameters were analysed using the mixed model methodology in a completely randomised design with 12 genotypes and four replications of 25 seeds. All biometric and emergence traits of seeds showed phenotypic and genetic variabilities. Heritability was high for all traits evaluated (0.66 to 0.97), and genetic accuracy showed high experimental precision and reliable results (≥ 0.90). Grouping by the Tocher, unweighted pair group with arithmetic mean and principal component analysis methods based on genetic traits returned four groups: Group 1 by Genotypes 1, 4, 5, 6, 7, 8, 9, 10 and 12; Group 2 by Genotype 3; Group 3 by Genotype 2; and Group 4 by Genotype 11. In addition, Genotypes 1, 3–10 and 12 displayed seeds with superior physical and physiological traits and a high probability of genetic gain. Our findings can be used in the selection and marking of trees with a broad genetic base for seed production and plant breeding of this species.</strong></p> 2024-01-23T00:00:00+00:00 Copyright (c) 2024 Delayed rooting hormone application and stem cutting collection time improved <i>Flacourtia indica</i> rooting ability and root growth 2024-01-23T06:41:01+00:00 Simon A Mng’omba <p><strong><em>Flacourtia indica </em></strong><strong>(Burm.f.) Merr. is an important fruit and medicinal tree in Southern Africa. Efforts to achieve early fruiting have failed with juvenile propagules (planting materials) such as seed. Assessing rooting ability of mature (fruit bearing) </strong><strong><em>F. indica </em></strong><strong>stem cuttings is vital to attaining early fruiting, or precocious fruiting, which reduces the long juvenile phase experienced by many woody fruit trees when propagated from seeds (juvenile planting materials). The objectives of this study were to assess responses of mature stem cuttings to different application times of rooting hormone (Seradix<sup>®</sup></strong> <strong>No. 2) and collection times of stem cuttings, and also to identify important pheno-phases in the yearly tree growth cycle of </strong><strong><em>F. indica</em></strong><strong>. A significantly higher rooting percentage (</strong><strong><em>p </em></strong><strong>&lt; 0.001) was obtained with delayed Seradix<sup>®</sup></strong> <strong>No. 2 application than with immediate application. Stem cuttings collected at flowering and leaf fall seasons were responsive to Seradix<sup>® </sup>No. 2 application, but all stem cuttings collected at fruiting time failed to produce roots. For stem cuttings collected during flowering time, immediate Seradix<sup>®</sup></strong> <strong>application resulted in significantly (</strong><strong><em>p </em></strong><strong>= 0.0482) more roots than in stem cuttings subjected to delayed Seradix<sup>®</sup></strong> <strong>application. The failure to produce roots of cuttings collected at fruiting time could be due to low sugars (carbohydrates) in the stem cuttings. The study concluded that the best time to collect stem cuttings from mature </strong><strong><em>F. indica </em></strong><strong>trees for rooting is either at flowering or leaf fall stages and that delayed Seradix<sup>®</sup></strong> <strong>No. 2 application improves rooting of stem cuttings from mature </strong><strong><em>F. indica </em></strong><strong>trees.</strong></p> 2024-01-23T00:00:00+00:00 Copyright (c) 2024 Effects of succinic acid impregnation on physical properties of sapwood and heartwood from plantation-grown short-rotation teak 2024-01-23T06:46:52+00:00 Sarah Augustina Teguh Darmawan Sudarmanto Narto Narto Adik Bahanawan Danang S Adi Dimas Triwibowo Yusup Amin Imran A Sofianto Prabu S Sejati Wahyu Dwianto Witjaksono Ragil Widyorini Philippe Gérardin Sari Delviana Marbun <p><strong>The aim of this study was to improve the properties of 15-year-old short rotation teak wood using a succinic acid (SA) treatment without excessively increasing the weight gain. The samples were classified as sapwood (SW) and heartwood (HW). Samples were immersed in 10% concentration SA solutions (w/w), followed by vacuuming at –50 kPa for 30 minutes, and applying 7 MPa of pressure for 2 hours. They were then analysed for specific gravity (SGs), dimensional stability, including tangential/radial ratio (T/R Ratio) and water absorption (WA), weight percent gain (WPG), chemical uptake (CU) and void volume filled (VVF). Our results showed that SGs increased in treated SW and HW by 2.33% and 1.23%, respectively, as compared to the untreated wood (0.60 and 0.66). The increase in SGs was the result of SA penetration into wood cell walls. The WPG and CU values increased slightly to 5.54% and 0.87 g cm<sup>−3</sup> for SW and 3.46% and 0.62 g cm<sup>−3</sup></strong> <strong>for HW, respectively. The greater increase of SGs in treated SW is due to a greater ease of treatability in SW than HW. The T/R ratio of treated HW decreased by 29.34% from the initial T/R ratio, whereas SW remained unchanged. The WA of treated SW and HW decreased by 42.67% and 55.46%, respectively compared to untreated wood. Treated wood performed better on dimensional stability, especially in terms of T/R ratio and WA values for HW. Our results show that the impregnation of short rotation teak wood with SA provides a significant increase on dimensional stability with a negligible increase in weight gain.</strong></p> 2024-01-23T00:00:00+00:00 Copyright (c) 2024 A systematic review of remote sensing and machine learning approaches for accurate carbon storage estimation in natural forests 2024-01-23T06:04:50+00:00 Collins Matiza Onisimo Mutanga Kabir Peerbhay John Odindi Romano Lottering <p><strong>The assessment of carbon storage in natural forests is paramount in the ongoing efforts against climate change. While traditional field-based methods for quantifying carbon storage pose challenges, recent advancements in remote sensing and machine learning offer efficient and innovative alternatives. This systematic literature review investigates the latest developments in utilising optical, radar, and light detection and ranging (LiDAR) remote sensing data, coupled with cutting-edge machine learning algorithms, to estimate carbon storage in natural forests. Non-parametric machine-learning algorithms commonly applied to multispectral datasets have emerged as prominent tools for predicting aboveground carbon storage. Nonetheless, accurately assessing forest carbon storage using remote sensing data can be arduous in regions characterised by complex terrain and diverse species where dataset noise may be pronounced. Alternatively, the adoption of freely available optical sensors with moderate resolution has showcased reliability in estimating forest carbon storage. Hence, leveraging the integration of multi-sensor data with machine learning techniques has yielded substantial improvements in the accuracy of carbon storage estimation. This study identifies the most sensitive remote sensing variables that correlate with measurable biophysical parameters, thus highlighting the pivotal role of geospatial technologies in estimating terrestrial aboveground carbon storage. The study also delineates gaps and limitations inherent in current practices, underscoring the need for further investigations in this rapidly evolving field. Through the unification of conventional methods with state-of-the-art technologies, this study contributes to the advancement of accurate and efficient carbon storage assessments. By assuming such a transformative role, this research holds substantial promise in bolstering global climate change mitigation efforts. Ultimately, the purpose of this study was to demonstrate to researchers, policy makers and practitioners the importance of embracing the combined power of remote sensing and machine learning as a tool for safeguarding our natural forests and fight against climate change.</strong></p> 2024-01-23T00:00:00+00:00 Copyright (c) 2024