Regulating industrial forest concessions in Central Africa and South America

Tropical countries face special specific problems in implementing sustainable forest management (SFM). In many countries, questions are raised on whether tropical forests should be publicly, commonly or privately owned and managed in order to enhance sustainability. Other debates also focus on whether small-scale enterprises are better positioned than large-scale industrial concessions to reduce poverty and attain sustainable management. In countries where large tracts of forest are state-owned, concessions are viewed as a means of delivering services of public and collective interest through an association of private investment and public regulation. However, the success of an industrial concession model in countries with large forest resource endowment to achieve multiple goals such as sustainable forest management and local/regional development depends on two critical assumptions. First, forest functions and services should be managed and maintained as public goods. In many cases, additional uses – and corresponding rights – can take place alongside logging activities. Industrial concessions can be more efficient than other tenure models (such as community-based forest management and small-scale enterprises) in achieving SFM, add value to raw material and comply with growing environmental norms. This is especially the case in market-remote areas with low population density and poor infrastructure. Secondly, to achieve these different outcomes, any concession system needs to be monitored and regulated, especially in contexts dominated by asymmetrical information between regulating authorities and concessionaires. New institutional responses have recently been put forward in several countries, providing valuable materials to design a renewed policy mix which associates public and private incentives. This paper provides a survey of the experience of forest concessions in several Central African and South American countries. The concession system is examined in order to clarify the issues involved, the problems encountered, and what can be learned from the shared experience of these countries in the last decade. This paper argues that despite a sometimes patchy record, concessions can help promote SFM so long as they are packaged with a certain number of specific measures.     

南非林业发展及启示与两国林业合作展望

中国正在加强实施"走出去"战略,寻求多元化的林业国际合作。南非是非洲最为发达的国家,并且与中国同为发展中国家和金砖国家。文中以FAO和南非农林渔业部等机构最新资料和数据为依据,介绍南非森林资源、林业法规、管理机构、森林经营管理、森林旅游、林产品生产与贸易等林业发展现状,探讨其土地产权问题、林业转型和社区参与对中国林业发展的一些启示,并提出中国可与南非在精准提升森林质量、林产品贸易、森林资源开发以及旱区造林技术等领域深入合作,为加强双边合作提供参考,对提升中国林业在非洲乃至国际上的形象与影响力具有重要意义。     

A comparison between excavator-based harvester productivity in coppiced and planted Eucalyptus grandis compartments in KwaZulu-Natal,South Africa

Due to the labour challenges in South Africa, mechanised forestry equipment has increasingly been required to operate in complex forest conditions – such as coppiced Eucalyptus compartments – where they have not operated before. For this reason, harvesters are either used in certain coppiced compartments with uncertain productivity expectations, or harvesters are not used in these compartments due to a lack of productivity knowledge. This research aimed to determine the influence of tree volume and tree form on the productivity of an excavator-based harvester in coppiced regrowth – with either double or single stems, or planted single stems – in Eucalyptus grandis pulpwood compartments. In addition, the stem felled first and the distance between stems were investigated for coppiced double stems. The stem felled first is whichever stem between the two coppiced double stems the harvester grabbed, felled and processed first. The tree volume was determined; thereafter the trees were classified into different form classes. The tree volume and the cycle time were used to determine productivity. The research results showed that planted trees had the highest productivity across all tree sizes, followed by coppiced single stems and then coppiced double stems. When harvesting a 0.2 m³ tree, the mean harvester productivity was 8.7 m³ per productive machine hour (PMH₀) in coppiced double stems, 13.8 m³ per PMH₀ in coppiced single stems and 16.1 m³ per PMH₀ in planted trees. In coppiced double stems the productivity was significantly influenced by the size of the stem felled first. In coppiced double stems the productivity was not significantly influenced by the distance between stems. The productivity for both coppiced single stems and coppiced double stems was significantly influenced by stem form. The poorly formed trees had lower productivity compared to the trees with good form.     

Alternative eucalypts for commercial pulpwood production at moderately dry sites in the warm temperate zone of KwaZulu-Natal,South Africa

During 2001, a series of four site–taxa interaction trials was established in the warm temperate (mean annual temperature range 16–19 °C) forestry climatic zone of KwaZulu-Natal (KZN), South Africa. The main objective was to investigate the commercial forestry potential of a range of alternative Eucalyptus and Corymbia taxa for moderately dry (mean annual precipitation < 850 mm) sites within the zone. At rotation end, all trials received final standing tree measurements. At one of the sites (Rockvale), trees of eight promising alternative taxa were felled, stem measurements and wood samples taken, and wood and fibre productivities determined. On the basis of tree growth and wood and fibre production, C. citriodora subsp. variegata, C. henryi, E. badjensis, E. benthamii and E. dorrigoensis (listed alphabetically) demonstrated the greatest potential as commercial alternatives for moderately dry sites in the KZN warm temperate zone. The majority of these taxa showed strong site specificity. Eucalyptus benthamii was the only taxon showing high growth adaptability to the entire range of site conditions applied in the series. The non-susceptibility of C. citriodora subsp. variegata and C. henryi to the current topical insect pests Thaumastocoris peregrinus, Leptocybe invasa and Glycaspis brimblecombei elevates the appeal of these taxa as potential alternative planting choices for moderately dry sites within lower altitude (<1 100 m asl) areas of the climate zone. The matching of the most promising alternative taxa in the series to the range of sites encountered in moderately dry areas of the KZN warm temperate forestry zone is discussed in this paper.     

南雄青嶂山常绿阔叶林优势物种组成与结构分析

基于1 hm2的固定样地数据,对粤北南雄小流坑—青嶂山保护区亚热带常绿阔叶林的物种多样性及优势植物种群的年龄、高度结构等特征进行了分析,以探讨森林群落的稳定性与演替进程.结果表明,样地中出现胸径≥1.0 cm的植物38科58属74种,个体总数1621株,建群种为木荷(Schima su-perba)和红锥(Castanopsis hystrix),重要值分别为16.56和12.00;优势种为赤皮青冈(Cyclobalanopsis gilva)、黄樟(Cinnamomum porrectum)、华润楠(Machilus chinensis)、青冈(Cyclobalanopsis glauca);群落优势科为山茶科、壳斗科、樟科、茜草科;群落整体上处于稳定阶段,其中木荷和青冈为稳定至早衰种群,红锥和赤皮青冈为基本稳定种群,华润楠为稳定种群,黄樟为衰老种群;各植物种群高度结构各具特色,其中木荷、华润楠和青冈对整个群落的高度结构影响较大.     

Ramet population structure of Fargesia nitida in different canopy conditions of the subalpine dark coniferous forest in the Wolong Nature Reserve, China

The bamboo Fargesia nitida, one of the giant panda’s main food sources and the dominant shrub species of the forest understory, is mainly distributed in the dark coniferous belt in western Sichuan and southern Gansu in China. To study the impact of different forest canopy conditions on subalpine dwarf bamboo populations, ramet population structures of clonal Fargesia nitida were surveyed in: forest understory (FU), moderate gap (MG), large gap (LG) and marginal open space (MOS). In order to determine how the ramet structures could be affected and its effects on these four canopy conditions, a field survey of the age structure of Fargesia nitida population, its morphological traits and biomass was conducted in the Abies faxoniana forest situated in the Wolong Nature Reserve, western Sichuan, China. The main results were as follows. First, at the ramet level, the structures of the ramet populations in four canopy conditions were significantly different, and as the canopy density decreased, the mean height, basal diameter and biomass of the populations increased following the order: LG<MG<FU. Second, the biomass proportions of ramets modularly varied with different canopy conditions and leaf biomass proportion was positively related to the canopy density except for the MOS where the biomass proportions of rhizome and roots were both higher than those in the three other canopy conditions. Third, ramet specific leaf weight increased in parallel with the decrease in canopy density. In the MG, the values of the individual leaf biomass and leaf area were the largest, followed by those in the MOS. Both the individual leaf biomass and leaf area were significantly different from those in the FU and LG. Leaf number per ramet was significantly different among the four different canopy conditions and the biggest in the LG. Fourth, the ramet population mortality was the lowest in the FU (Chi-square test, p < 0.01), while there was no significant difference in the average population age (Mann-Whitney test, p > 0.05). All the results indicated that it was not ramet age, but the morphological changes and biomass distribution that exhibited the response of the ramet population of Fargesia nitida to the changed canopy conditions. Translated from Acta Ecologica Sinica, 2006, 40(1): 730–736 [译自: 生态学报]     

Mangrove species zonation and soil redox state,sulphide concentration and salinity in Gazi Bay (Kenya), a preliminary study

The relationship between soil redox state, sulphide concentration, salinity and spatial patterns of mangrove species distribution was investigated in the mangrove forest of Gazi Bay (Kenya). Field measurements were conducted to examine the relationship between species distribution along a band transect of 280m and soil redox potential (Eh) and sulphide patterns, as well as the indirectly related (through flooding regimes) soil salinity. Of the three major species Avicenniamarina, Ceriops tagal and Rhizophoramucronata present along the transect, only the distribution of the latter correlated with the measured soil variables, R. mucronata being absent from the lessreduced zone with high salinity. Bruguieragymnorhiza and Heritieralittoralis occur in minor populations, they are restricted to the saline, sulphidepoor and lessreduced substrates. From the results it is concluded that soil redox potential (Eh), sulphide concentration and salinity may contribute to structure mangroves through the distribution of dominant species, however in combination with other environmental conditions and processes of vegetation dynamics.     

Wood density,phytomass variations within and among trees,and allometric equations in a tropical rainforest of Africa

The development of tree allometric equations is crucial to accurate forest carbon assessment. However, very few allometric equations exist for sub-Saharan Africa and as a result generalized allometric equations, often established for forests in other continents, are used by default. The objectives of this study were (1) to propose a sampling methodology and calculation procedures to assess biomass for tropical tree species of contrasted tree shapes in Africa, (2) to identify factors affecting within and between trees wood density, (3) to propose an allometric model that integrates these factors and (4) to evaluate the reliability of using generalized allometric equations in this type of forests. Models were developed to predict wood density and phytomass of the trees based on the harvesting of 42 trees from 16 species, representing three guild status in the wet evergreen forest of Boi Tano in Ghana. Results indicated that the wood density was highly influenced by the tree species, guild status, size of the tree and pith to bark distance. Dry mass of a tree was influenced by diameter at breast height, crown diameter and wood density. The wood density depends on the position of the wood within the tree and the guild status considered. The use of generalized allometric models in literature is limited by the specific climate zone, the consideration of tree height and species specific wood density. In considering those factors, using generalized allometric equations could result in an error of 3%. Further research should better consider the bigger trees and the influence of the topography and ecosystem history.     

Spatial patterning and population structure of a common woodland herb, Trillium erectum, in primary and post-logging secondary forests

We investigated the population age structure and spatial patterning of a common understory perennial, Trillium erectum var. album, in primary and post-logging secondary (industrially logged in the early 1900s) cove forests of the southern Appalachian Mountains. Within each of 8 T. erectum populations (4 in primary forest and 4 in secondary forest), we mapped the locations of all T. erectum plants in a 10 m × 10 m plot located within the center of each population. We recorded the height and life stage of each plant and excavated a randomly selected subset for age determination. Trillium erectum populations in primary forests displayed a somewhat stronger and more consistent spatial structure than those found in secondary forests. However, aside from being on-average younger due to a higher concentration of juveniles, age structures of secondary forest populations were similar to those of primary forests and both forest types had similar maximum plant ages. Our results, when considered with the life history of the species, suggest that logging did not eliminate T. erectum from secondary forests. Rather, residual plants and patches of plants that survived logging provided the propagules needed to expand and reestablish populations following logging. This relatively rapid recovery stands in stark contrast to the slow recovery observed by others in post-agricultural secondary forest. When considered in the context of other studies of post-disturbance recovery in secondary forests, our results suggest that the full history of a site must be carefully considered when examining the impacts of disturbance on forest perennial herbs.     

Temperate forest dynamics and carbon storage: a 26-year case study from Orange Kloof Forest,Cape Peninsula,South Africa

Temperate forests are globally important carbon stores that are, in the face of recent improvements in their conservation, likely to increase their storage capacity in the future. Despite this, these ecosystems are poorly understood, especially over longer time periods. To remedy this and to better understand these important ecosystems, we monitored marked stems >5 cm diameter at breast height (DBH) in a 0.52 ha forest plot on the Cape Peninsula over 26 years. Aboveground biomass (AGB), calculated from stem diameter, increased from 203 to 226 Mg ha^?1 over this period. The AGB residence time was greater than a century. Stem mortality was relatively high (1.2% per annum [p.a.]) and exceeded recruitment (0.2% p.a.). The recruitment of a large number of smaller stems of species not presently represented in the forest canopy suggests that compositional changes will occur in the future. Overall, these results suggest that the forest is in a post-disturbance recovery phase, although favourable climatic conditions over the last three decades may also have had an influence on AGB accumulation.     

Impact of land-use type and bark- and leaf-harvesting on population structure and fruit production of the baobab tree (Adansonia digitata L.) in a semi-arid savanna,West Africa

Non-timber forest products (NTFPs) strongly contribute to livelihood security in the semi-arid tropics. There is increasing concern about the population status of NTFP-providing trees and therefore a need for their sustainable use. Thus, this study examines the impact of land-use type on the multipurpose baobab tree (Adansonia digitata L.) in Burkina Faso, combined with rates and patterns of bark- and leaf-harvesting, and their impact on fruit production. We compared stands in a protected area (W National Park of Burkina Faso) with those of surrounding communal area (fallows, croplands and villages) to obtain an indication on the status of the baobab population, to assess its harvesting tolerance and to estimate to what extent their actual use is sustainable. Our results reveal that land-use type has an impact on the population structure of the baobab. The size class distribution curve of park stands was inverse J-shape which indicates good rejuvenation, while the curve of fallows, croplands and villages stands was bell-shaped, indicating a lack of recruitment. However, a high number of seedlings were recorded in villages. Nearly all baobabs were pruned and debarked in villages, croplands and fallows while half of the individuals were harvested in the park. Most of the trees were pruned and debarked moderately. Debarking and pruning were slightly size specific. Pruning in interaction with tree-size had a significant impact on fruit production. In contrast, debarking had no effect on fruit production. We conclude that despite the land-use impact and the intense harvesting, baobabs are still well preserved in the communal area due to their longevity, extremely low adult mortality rates and traditional management practices. However, land-use intensifications may lead to increasing pressure on baobab populations in the future. Therefore, adapted management strategies are needed to guarantee the persistence of this important species and to avoid a shortage of baobab products.     

Relationship between landscape structure and burn severity at the landscape and class levels in Samchuck, South Korea

Fuel treatments for reducing fire risk are necessarily tied to the landscape structure including forest composition and configuration. Thus understanding the relationships between landscape structure and burn severity is important for developing guidelines and management strategies for fire-resilient forests. The goal of this study was to investigate the relationship between landscape structure as described by spatial pattern metrics and burn severity at the landscape and class levels. In 2000, a mostly severe fire burned 16,210 ha of dense forest located in Samchuck on the east coast of the Korean peninsula. Spatial pattern metrics including patch density, largest patch index, mean shape index, area-weighted mean shape index, Euclidean nearest neighborhood distance, and Shannon's diversity index, as well as topographic characteristics of slope and elevation, were correlated with burn severity based on delta Normalized Burn Ratio (dNBR) assessments. Regression tree analysis was also carried out with the same variables to avoid spatial autocorrelation and to reveal the relative importance of variables to burn severity. The results of this study strongly suggest that both composition and configuration of the forest cover patches are closely tied to burn severity. In particular, both the correlation analysis and regression tree analysis indicated that the area of red pine tree forest cover was the most significant factor in explaining the variance of burn severity. Topography and spatial configuration of forest cover patches were also significantly related to burn severity. The heterogeneity of forests also had a significant influence on burn severity. To reduce fire risk and increase the fire resilience of forests, forest managers and agencies need to consider enhancing the heterogeneity of forests when implementing fuel treatment schemes. However, such fuel treatments for landscape structure may only be effective under moderate weather conditions.     

Effects of site management on growth,biomass partitioning and light use efficiency in a young stand of Eucalyptus grandis in South Africa

The effects of intensive site management treatments at establishment on the production ecology of a stand of Eucalyptus grandis were evaluated in South Africa. Treatments mimicked common operational practices in the region, and included slash removal, slash conservation, slash burning, topsoil disturbance through mechanised harvesting and fertilisation. We calculated the carbon distribution in the standing biomass from allometric relationships. Fine root turnover and litterfall measurements were determined using sequential coring techniques and litter traps, respectively, and this data was used to construct a full model of biomass allocation among stand components. Differences in nutrient availability to young trees, brought about by the most extreme site management treatments, produced several small but significant changes in the elements of the system's production ecology: Absorbed photosynthetically active radiation (APAR) increased from 210 to 247 Mmol photons ha⁻¹ over the 3-year monitoring period, apparent canopy quantum efficiency (α; defined as gross primary production per unit of APAR) from 0.026 to 0.029 mol C (mol photon)⁻¹, and the fraction of carbon allocated to stem wood from 32.7% to 35.6% of net primary production. The magnitudes of these individual responses collectively described the increase in net primary productivity and the Type 1 timber volume response obtained. The biggest changes occurred in APAR, in contrast to published studies from higher rainfall environments where differences in nutrient availability caused greater changes in α than in APAR.