Carbon Accumulation and Partitioning Above and Belowground under Coppiced and Replanted Eucalypt Plantations

The extent to which the C sink strength of eucalypt plantations can be affected by coppicing or replanting remains unclear. To address this issue, we evaluated variations in C stocks under coppiced or replanted eucalypt stands formed by clones or seedlings. For each field assessment (0 [T0], 2.5, 3.5, 4.5, 5.5 and 7.0 years [at harvest]), tree biomass, litterfall, and soil C stocks (0–120 cm depth) were determined. At harvest, debarked stemwood productivity was similar under coppice or replanting, about 50.0 Mg C ha–1. Generally, coppiced stands favored subsoil C storage (40–100 cm), whereas replanted stands favored soil C accrual in topsoil (0–20 cm), depending on the genetic material. Relative to T0, soil C increased about 2.14, 1.91, and 1.84 Mg C ha–1 yr–1 under coppice, replanting with seedlings and clones, respectively. Coarse root biomass under these stands were about 17.3, 13.4, and 9.5 Mg C ha–1, respectively, equivalent to 50% of total harvest residues. Hence, inputs from coarse roots could represent a large contribution to soil C over multiple rotations under coppiced or replanted stands. Otherwise, short-term C losses can be high where stumps and coarse roots are harvested, especially following successive coppice cycles. Study Implications: Our findings have important implications for forest managers growing eucalypt plantations aiming to maximize C accumulation. Both coppiced and replanted stands can fix up to 50 Mg C ha−1 only in debarked stemwood over 7 years, with a comparatively higher C storage in coarse roots under coppice. Despite the increasing demand for forest residues in bioenergy production, harvesting stumps and coarse roots should be avoided, especially upon replanting eucalypt stands after successive coppice cycles.

The sustainability of reforesting landscapes with exotic species: a case study of eucalypts in Ethiopia

Eucalypt reforestation has been a common feature of many countries, especially in the developing countries, such as Ethiopia. Farmers in Ethiopia plant large numbers of eucalypts on small areas of land and manage them to yield a variety of products, including leaves and small branches for fuelwood, and poles and posts for house building and other farm uses. Many people in Ethiopia are dependent on eucalypts as a source of fuel and house building material. The use of trees, especially eucalypts, as a living bank account, to be harvested when there is a need for cash, is widespread. This being the reality, the arguments for and against planting eucalypts in Ethiopia has been mounting from time to time, especially associated with water use, soil fertility, soil erosion, allelopathic effects, understory vegetation and plant diversity as well as wild animals. The paradox of reforestation using eucalypts results, mostly, from inappropriate species-site matching and poor management rather than the inherent biological characteristics of the species. Therefore, the debate on eucalypts under the pretext of concern for indigenous species and natural forests should shift to how both plantations established using eucalypts and indigenous species as well as natural forests can help in the enhancement of the socio-economic development and environmental conservation of countries, such as Ethiopia. Despite the claimed negative impacts of eucalypts, farmers in Ethiopia have utilized their traditional knowledge and experience in establishing and managing eucalypt stands. In addition, the available reports in Ethiopia are in favour of planting eucalypts since the authors acknowledge that: (i) the negative impacts can be minimized provided that the choice of species and site as well as the management of the stands are appropriate, (ii) the benefit derived can offset the losses that can occur from such plantations, (iii) no other species seems to replace them to bridge the ever-widening gap between demand and supply of wood and (iv) the profit derived from eucalypt plantations is considerably higher than cultivating crops. However, the choice of eucalypt species should be based on many criteria, for example maximum wood production, ecological sustainability, marketability of the planted species and usefulness of the species to the local populations. All these criteria involve not only a choice of species planted, but also a choice of plantation management methods from initial planting to final cutting of the trees. Careful selection of appropriate species and matching them with appropriate sites must be taken as prerequisite, and the right management practices should be employed.

A Long-Term Follow-Up Study of Slash Bundling in Fast-Growing Eucalypt Plantations

The Authors conducted a long-term follow-up study of a John Deere 1490 forwarder-mounted bundler owned by a Portuguese company and used for bundling logging residues from fast-growing eucalypt plantations located in Portugal and Spain. The study spanned 7 years, from 2011 to 2016. During this time, the machine clocked over 11,500 h and produced more than 200,000 bundles or 75,000 green tons of biomass. Bundle length was commonly 2.4 m, and bundle mass averaged 350 kg. Overall, the database contained 1752 daily records. Bundling productivity averaged 19 bundles per productive machine hour (meter hour, excluding all major delays). Mechanical availability was very high and averaged 93%. Utilization commonly ranged between 65% and 75%. Use and productivity showed a predictable seasonal trend and a slight decline over time. The latter might be due to wear, but also due to the increasingly challenging conditions faced by the company as the average worksite size sharply decreased from 2011 onwards. While almost extinct elsewhere, bundling seems to thrive in the Iberian plantations, possibly due to the industrial character of both eucalypt farming and bioenergy generation in the region. That allows the reaping of all integration benefits offered by bundling, while the cost of setting up a parallel biomass chain is minimized. Furthermore, bundling seems the ideal technique for efficient residue recovery where slash yields are low and roadside storage space is limited: these are the typical constraints of industrial eucalypt plantations, where planted area is maximized (=little landing space) and the largest possible proportion of the tree mass is turned into pulpwood (=relatively low residue yield).

Perceptions on Impacts of Competition of Eucalypt Plantations with Other Land Uses on the Rural Livelihood in the Western Gurage Watersheds, Central-South Ethiopia

Since recent years, conversions of croplands, grasslands or cash crop fields to eucalypt plantations are becoming common trends in Ethiopia. Reasons for the conversions are better return from eucalypt than crop farming. This study tried to assess the land use competition impacts of eucalypt plantations with other land uses in the Western Gurage Watersheds, Central-south Ethiopia. The specific objectives were to investigate households’ and experts’ perceptions on land use competition of eucalypt plantations; and to assess perceptions on impacts of eucalypt plantation and copping strategies. Samples from three woredas (districts) namely Cheha, Enemorna Ener, and Eza located in the Watersheds were used. These woredas were purposefully selected due to large coverage of the watersheds, extensive expansion of eucalypts farming and thereby high eucalypts pole production, incidences of serious competition of eucalypts with other uses, and the presences of road accessibility for data collection. To get detail information on perception of the households and experts, in-depth discussions with focus groups and key informant were employed. Individual farm households whose age were greater than 70 years old and knowledgeable persons to discuss on the issue of eucalypt plantations were selected purposefully with the guidance of each kebele (sub-district) chairpersons and district experts. Thereafter, three focus group discussions with farm households were conducted in the three districts. Key informant interviews were conducted with purposefully selected and well experienced individual farm households and experts in each district. The result showed that young farmers planted from 1000 to 5000 eucalypt seedlings on lands previously covered with crops. The young people resisted advice from elders and converted farmlands to eucalypt plantations. Previous practitioners (adoptees) who benefitted much from eucalypt products tended for further expansion. This, in turn, resulted in serious land use competition with farmland and grasslands. To mitigate such serious competition with food crops and grasslands, and to sustain the livelihood and environment, appropriate management, e.g. site selection and substitutions by horticultural and cash crops using micro irrigation schemes for market needs are recommended. Conducting in-depth participatory research and specific policy ratification and promulgation on eucalypt plantations will curb its serious land use competition with farm and grazing lands.

The Sustainability of Reforesting Landscapes with Exotic Species: Case Study of Eucalypts in Central-South Ethiopia

Background Rural landscapes, particularly those close to human settlements and main roads throughout the highlands of Ethiopia, appear greener than the outfields because of eucalypt plantations. The most common factors for eucalypt plantations are two: fuel and construction demands and to generate income. Objective This study tried to investigate the socioeconomic impacts of eucalypt plantations in Western Gurage Watersheds located in Central-south Ethiopia. The specific objectives are: to evaluate the socioeconomic importance of eucalypt plantations on the livelihood of farm households, and to assess perceptions on impacts of eucalypt plantation and copping strategies. Methods Systematic and purposive sampling method was employed by selecting households with eucalypt woodlots from the list of each Woreda’s Kebeles. Close- and open- ended questionnaires were distributed to every fifth households that possessed eucalypt plantations. Three hundred eighty three questionnaires were distributed and collected from households found in three Woredas (districts) namely Cheha, Enemorna Ener, and Eza located in the Watersheds. To supplement the information critical observations, discussions with focus groups and interviews with key informant were employed. The survey data were analyzed using both qualitative and quantitative techniques. To describe data acquired from critical observations, focus group discussions and key informant interviews; critical and logical qualitative data analysis technique were used. Descriptive and dispersive statistics such as frequency, percentage, mean, variance, standard deviation, p- value and correlation were employed using SPSS Version 20. Results The result showed that eucalypt plantation dominated fuel wood and construction consumption and substituted further encroachment to natural forests. From multiple responses given, households prefer planting eucalypts to indigenous trees because it is fast growing (100%), profitable (100%), needs lesser labor (100%), needs lower capital (100%), can be used for multipurpose (100%), and coppice itself fatly (93%). They rated income gained from eucalypt as 2nd next to enset. Conclusions Households may continue planting the species particularly for fuel wood and construction need since substituting it by other alternative seems not feasible and challenging. To sustain the livelihood and environment; appropriate management like site selection and substitutions by horticultural and cash crops using micro irrigation schemes for market needs are recommended. Conducting in-depth participatory research and specific policy ratification and promulgation on eucalypt plantations will sustain its utilization and curb the drawbacks.

The Socioeconomic impacts of Eucalypt Plantations on Rural Livelihood in Western Gurage Watersheds, Central-south Ethiopia

Background Rural landscapes, particularly those close to human settlements and main roads throughout the highlands of Ethiopia, appear greener than the outfields because of eucalypt plantations. The most common factors for eucalypt plantations are two: fuel and construction demands and to generate income. Objective This study tried to investigate the socioeconomic impacts of eucalypt plantations in Western Gurage Watersheds located in Central-south Ethiopia. The specific objectives are: to evaluate the socioeconomic importance of eucalypt plantations on the livelihood of farm households, and to assess perceptions on impacts of eucalypt plantation and copping strategies. Methods Systematic and purposive sampling method was employed by selecting households with eucalypt woodlots from the list of each Woreda’s Kebeles. Close- and open- ended questionnaires were distributed to every fifth households that possessed eucalypt plantations. Three hundred eighty three questionnaires were distributed and collected from households found in three Woredas (districts) namely Cheha, Enemorna Ener, and Eza located in the Watersheds. To supplement the information critical observations, discussions with focus groups and interviews with key informant were employed. The survey data were analyzed using both qualitative and quantitative techniques. To describe data acquired from critical observations, focus group discussions and key informant interviews; critical and logical qualitative data analysis technique were used. Descriptive and dispersive statistics such as frequency, percentage, mean, variance, standard deviation, p- value and correlation were employed using SPSS Version 20. Results The result showed that eucalypt plantation dominated fuel wood and construction consumption and substituted further encroachment to natural forests. From multiple responses given, households prefer planting eucalypts to indigenous trees because it is fast growing (100%), profitable (100%), needs lesser labor (100%), needs lower capital (100%), can be used for multipurpose (100%), and coppice itself fatly (93%). They rated income gained from eucalypt as 2nd next to enset. Conclusions Households may continue planting the species particularly for fuel wood and construction need since substituting it by other alternative seems not feasible and challenging. To sustain the livelihood and environment; appropriate management like site selection and substitutions by horticultural and cash crops using micro irrigation schemes for market needs are recommended. Conducting in-depth participatory research and specific policy ratification and promulgation on eucalypt plantations will sustain its utilization and curb the drawbacks.