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Background: Since the 1990's, afforestation programs in the páramo have been implemented to offset carbon emissions through carbon sequestration, mainly using pine plantations. However, several studies have indicated that after the establishment of pine plantations in grasslands, there is an alteration of carbon pools including a decrease of the soil organic carbon (SOC) pool. The aim of this study is to investigate the impact of the establishment of pine plantations on the carbon stocks in different altitudes of the páramo ecosystem of South Ecuador. Results: At seven locations within an elevational gradient from 2780 to 3760 m a.s.l., we measured and compared carbon stocks of three types of land use: natural grassland, grazed páramo, and Pinus patula Schlltdl. & Cham. plantation sites. For a more accurate estimation of pine tree carbon, we developed our own allometric equations. There were significant (p < 0.05) differences between the amounts of carbon stored in the carbon pools aboveground and belowground for the three types of land use. In most of the locations, pine plantations revealed the highest amounts of aboveground and belowground carbon (55.4 and 6.9 tC/ha) followed by natural grassland (23.1 and 2.7 tC/ha) and grazed páramo sites (9.1 and 1.5 tC/ha). Concerning the SOC pools, most of the locations revealed significant lower values of plantations' SOC in comparison to natural grassland and grazed páramo sites. Higher elevation was associated with lower amounts of pines' biomass. Conclusions: Even though plantations store high amounts of carbon, natural páramo grassland can also store substantial amounts above and belowground, without negatively affecting the soils and putting other páramo ecosystem services at risk. Consequently, plans for afforestation in the páramo should be assessed case by case, considering not only the limiting factor of elevation, but also the site quality especially affected by the type of previous land use. [ABSTRACT FROM AUTHOR]

If tropical farmers cannot be provided with sustainable land-use systems, which address their subsistence needs and keep them gainfully employed, tropical forests will continue to disappear. We looked at the ability of economic land-use diversification - with reforestation of tropical "wastelands" as a key activity - to halt deforestation at the farm level. Our ecological-economic concept, based on land-use data from the buffer area of the Podocarpus National Park in southern Ecuador, shows that stopping deforestation after 10 years is possible without violating subsistence demands. Tropical, farm-level diversification may not only reduce total deforestation by 45%, but also increase farmers' profits by 65%, because the formerly unproductive wastelands have been returned to productive land use. We therefore conclude that a "win-win" scenario is possible: the subsistence needs of people can be reconciled with conservation objectives. However, inexpensive microcredits (at interest rates below 6%) and experience on alternative land-use opportunities must be offered to farmers. [ABSTRACT FROM AUTHOR]

Abstract: The Andes of Ecuador are known for their outstanding biodiversity but also as the region with the highest deforestation rate in South America. This process is accompanied by accelerating degradation and loss of environmental services. Despite an extraordinary richness in native tree diversity, more than 90% of all forest plantations established in Ecuador consist of exotic species, primarily Eucalyptus spp. and Pinus spp. This is mainly due to the lack of information about the autecological and synecological requirements of the native species. The present study aims at providing basic knowledge on the early height development of native species in comparison to exotics. 12,000 seedlings of exotic and native species were planted in experimental trials at three sites of different successional stages: recently abandoned pastures (Setaria sphacelata), bracken (Pteridium arachnoideum) and shrubs. The results presented in this study refer to the status of the seedlings 3 years after planting. Soil data were revealed from soil core analysis from a total of 1008 soil samples distributed systematically over all plots. Soil chemical data were derived from a subsample of 125 randomly selected soil core sites. Soil properties in the study area emerged to be extremely heterogeneous. More than 60% of all plots presented two or more soil clusters. Soils in general were very poor in plant available N. Soil heterogeneity affected extractable Mn and Mg, dominating vegetation cover in turn affected Mn and P. Differences in soil properties had a strong effect for Eucalyptus saligna and Alnus acuminata. Manual above ground weeding showed species-specific effects: Tabebuia chrysantha and Heliocarpus americanus showed improved height growth, while that of Cedrela montana was reduced. There is evidence that A. acuminata can compete in growth with exotic species. Early successional species and exotics performed best on pasture dominated sites. Height growth of the mid-successional species C. montana was facilitated by bracken fern under certain soil conditions, and shrubs facilitated growth of T. chrysantha. The results indicate that reforestation with native species in Ecuador is possible but requires intensive consideration of interactions with soil properties and accompanying vegetation. Macroscopic soil core analysis can be a suitable instrument for detecting small-scale variation of soil properties. Nevertheless, a characterisation of both small-scale variation as well as variation on higher spatial scales, for instance by aerial photographs, is essential for effective planning of reforestation measures in the Andes. [Copyright &y& Elsevier]

Abstract: Management of natural forests might be one option to reduce the high deforestation rate in Ecuador. We therefore evaluated the response of water and nutrient cycles in a natural tropical montane forest to improvement fellings with the aim of favoring economically valuable target trees which will later be harvested with additional ecosystem impacts not considered here. The study was conducted at ca. 1900–2200m above sea level in the south Ecuadorian Andes on the east-exposed slope of the east cordillera. In June 2004, one of two paired ca. 10-ha large catchments was thinned by felling 10.2% of the initial basal area (dbh≥10cm) on 30% of the catchment. The stems remained in situ. We measured ecosystem fluxes from rainfall via throughfall and stemflow to soil solution (litter leachate, soil solution at 15 and 30cm depth) and stream flow between May 2004 and May 2005. After the fellings, soil solutions were extracted from the gaps created by the felled trees and the forest next to the gaps. We determined aboveground water fluxes by direct measurement and soil water fluxes with a budget approach. In the solutions, we measured concentrations of NH4 +-N, NO3 −-N, total dissolved N, PO4 3−-P, total dissolved P, Ca, Mg, K, Na, and Cl−. Fluxes were calculated as volume-weighted mean (vwm) concentrations times water fluxes. Dry deposition was estimated using Cl− as inert tracer. The fellings increased concentrations of N, K, Ca, and Mg in the organic layer of the resulting gaps compared with the forest next to the gaps (vwm concentrations of N: 6.4mgl−1 in the forest next to the gap/8.7mgl−1 in the gaps, K: 9.8/11, Mg: 1.8/3.0, Ca: 3.4/5.8). Lower nutrient concentrations and fluxes in the mineral soil of the gaps than in forest next to the gaps suggested that these nutrients were taken up by ground vegetation and target trees. The paired modified and undisturbed catchments had similar water and nutrient budgets. The fellings did not have a significant impact on the water and nutrient budget at the catchment scale. [Copyright &y& Elsevier]

• Topographical position more relevant for growth than silvicultural treatment. • Growth rates of potential crop trees strongly decreased with increasing elevation. • Growth rates strongly decreased over the topographic gradient from valleys to ridges. • Overall response to silvicultural treatment was moderate but only marginally significant. • Treatment effect seemed positive for 5 timber species and nil for 3 species. Few studies have analysed the effect of silvicultural treatments on tree growth in tropical montane forests (TMF). These forests have strong topographic gradients, which influence growth rates and can potentially interact with silvicultural treatments. The present study investigated the relative effects of silvicultural treatments and topography on growth rates at the tree level in a TMF. For this, we combined two distinct data sources: (1) field data from a silvicultural experiment in the Andes of southern Ecuador where liberation thinnings, i.e. the removal of the strongest crown competitors, were applied to potential crop trees (PCT) in 2004; and (2) topographic variables obtained from a high-resolution digital terrain model created from an airborne LIDAR survey. We fitted all data in a single linear mixed-effect model. Based on monitoring data from 174 released and 200 reference PCTs of 8 timber species, we calculated periodic annual increment (PAI) in DBH 6 years after the silvicultural treatment as our outcome variable. As topographic predictors, we used elevation and a topographic position index. To control for the by-species growth variability we included random intercepts for species and random slopes for the effect of treatment on species in our model. PAI was significantly influenced by the topographic predictors. Over the elevational gradient, growth rates declined on average by 0.73 mm a−1 per 100 m increase in elevation. For the topographic position, PCTs in valleys had an average PAI of 2.02 mm a−1 compared to 1.04 mm a−1 on ridges. The effect of the silvicultural treatment across all species was only marginally significant, but its effect size was nevertheless within the range, but at the lower end of values reported for other tropical forest ecosystems (reference trees: 1.35 mm a−1; released trees: 1.60 mm a−1). Between species, baseline growth rates as well as the treatment effect varied considerably. Best linear unbiased predictions of species effects suggested that 5 species responded positively to the silvicultural treatment, whereas 3 species showed no treatment effect. Overall, tree growth varied substantially as indicated by the large residual variance that remained unaccounted for in the model. Our findings indicate that positive effects of silvicultural treatments in TMF are likely to exist, but that they are possibly obfuscated by strong topographical gradients and large between-tree growth variability. Overall, our results suggest that "broad-brush" management prescriptions are not suited for sustainable forest management of TMF. Instead, granular and spatially explicit prescriptions that take the strong impact of topography on diameter growth as well as species-specific responses to silvicultural treatments into account should be favoured. [ABSTRACT FROM AUTHOR]

During the 1980s, reforestation programs using exotic species (Pinus spp.) were established in the páramo ecosystem of Ecuador. The aims of this study were: (1) to compare the natural regeneration between pine plantations (Pi) and natural grassland (NG) across an elevational gradient and (2) to identify the attributes of Pi and soil properties that were influencing herbaceous and woody plant composition and their plant cover. In total, six independent Pinus patula (Schltdl. & Cham. plantations (two per each elevation) were selected and distributed in an elevational range (3200–3400, 3400–3600, 3600–3800 m a.s.l.). Adjacent to Pi, plots in NG were established for recording natural regeneration. Both, namely the attributes and the soil samples, were measured in Pi. The results showed that natural regeneration differs significantly between both types of vegetation. As expected, NG holds more plant diversity than Pi; the elevational range showed a clear tendency that there was more herbaceous richness when elevation range increases, while the opposite was found for woody species. Moreover, attributes of Pi influenced herbaceous and woody vegetation, when saturated hydraulic conductivity (Ksat) in the soil, basal area (BA) and canopy density (CD) increased, herbaceous species richness and its cover decreseased; and when Ksat and the acidity in the soil increased, woody plants richness and its cover decreased. The plantations have facilitated the establishment of shade tolerant species. More studies are needed to evaluate if removal with adequate management of pine plantations can improve the restoration and conservation of the native vegetation of the páramo ecosystem. [ABSTRACT FROM AUTHOR]