Clear-felled Stands Research Articles

Mature exotic conifer stands have greater catches of the EU-protected Geomalacus maculosus than adjacent peatland or clear-felled stands—implications for forestry

© 2017, INRA and Springer-Verlag France SAS, part of Springer Nature. Key message: Mature exotic Sitka spruce (Picea sitchensis; Bong. Carriere)-dominated stands, particularly trees of greater circumference, result in greater numbers ofGeomalacus maculosus(Allman) captures than adjacent clear-felled stands and adjacent peatland with Before-After-Control-Impact-Paired analysis indicating lower catches ofG. maculosuspost-felling. Context: The discovery of EU-protected Geomalacus maculosus in commercial plantations requires an understanding of the implications of forestry practices for the species within the context of sustainable forest management. Aims: 1.Compare Geomalacus maculosus captures across mature exotic Sitka spruce-dominated stands, previously clear-felled stands and adjacent peatland habitats.2.Assess the suitability, for forest managers, of population estimate models for G. maculosus.3.Assess the implications of felling by comparing relative abundances of G. maculosus directly before and after clear-felling at a mature exotic Sitka spruce-dominated stand. Methods: Geomalacus maculosus catches were compared at four sites across two to three mature (43–45 years old) conifer stands per site, one clear-felled stand per site, and one adjacent peatland per site using refuge traps and hand searching. Capture-mark-recapture studies were undertaken to estimate population sizes. A BACIP (Before-After-Control-Impact-Paired) analysis was undertaken in one forest stand at one forest site to determine impacts of a clear-felling event. Results: Mean catches of Geomalacus maculosus adults in the mature forest stands were over 10 and 11 times greater than mean catches on peatland and clear-fell stands, respectively. The Schnabel model for estimating population size was most suited for mature forest stands but could not be utilised for the other habitats. BACIP analysis showed a significant impact of clear-felling with a 95% reduction in mean G. maculosus catches after a clear-felling event where none of the individuals marked prior to felling were recaptured compared to 21% recapture rates at the control site. Greater tree circumference in mature conifer stands correlated with greater catches. Conclusion: Guidelines are needed to ensure the protection of Geomalacus maculosus in commercial forestry. Interventions could include patch/tall stump retention at final felling and/or translocation of the protected species.

Soil disturbance and early vegetation response to varying intensity of energy wood harvest

Forest biomass plays an important role in the production of renewable energy, particularly in northern Europe. During recent decades, tree stumps have also been increasingly used for energy production. The environmental impacts of stump removal on the functioning of forest ecosystems, for example on soil processes and biodiversity, are still inadequately understood. To investigate the separate impacts of tree stump and logging residue removal on soil and plant variables, we conducted a large-scale replicated experiment in clear-felled stands in three geographical areas. Four energy wood harvesting levels were combined with patch mounding (organic and mineral soil layer turned upside down) as a site preparation method. The harvesting treatments were: (1) no energy wood harvesting, (2) 70% logging residue removal, (3) 25 stumps per hectare left at site and 70% logging residue removal (maximum level in official recommendations), (4) complete stump and 100% logging residue removal. Soil disturbance in terms of mineral and organic soil cover increased with the increasing harvesting level, but complete stump removal did not increase the mineral soil cover more than partial stump removal (on average 95% removed). Despite the increase in soil disturbance, stump removal did not have an overall impact on plant species richness or vegetation composition in the second growing season after harvesting. However, an increasing trend in Betula spp. biomass with increasing harvesting intensity was seen in two of three study areas in four years. Our results underscored the high site-dependency of the effects of stump removal on ecological variables, thus the initial stand structure and vegetation type need to be considered when planning harvesting treatments.

Recovery of ground-dwelling assemblages during reforestation with native oak depends on the mobility and feeding habits of the species

Timber-oriented forest management causes significant changes to the environments, threaten the survival of many native species and it is responsible for the primary forest loss. Recognition of the scale and effects of the primary forest loss has resulted in a considerable degree of interest in the restoration. One of the serious efforts at restoration is the compulsory reforestation of the clear-felled stands of any (native or non-native) forests with native species. To evaluate the success of restoration efforts it is important to answer whether the diversity and composition of indigenous assemblages can recover after reforestation with native trees and to know how long is the recovery time? We studied ground beetles and millipedes from mature (130-year-old) oak forest, and recently established (5-year-old), young (15-year-old), and middle-aged (45-year-old) reforestation with native English oak by pitfall trapping and leaf litter sifting to assess the recovery dynamics of their diversity and composition. The overall number of the ground beetle individuals and species were significantly the highest in the 5-year-old reforestation, while the overall number of millipede individuals and species were significantly the lowest in the recently established reforestation. The elevated overall number of ground beetle individuals and species in the 5-year-old reforestation were due to the colonization of good disperser open-habitat species. The number of forest-associated ground beetle individuals and species were significantly the lowest in the 5-year-old reforestation, whereas from 15years after the reforestation, when the canopy has been closing, there was no significant difference in the number of forest species. The number of forest-associated millipede individuals and species were significantly the lowest in the 5-year-old reforestation; however, they were significantly the highest in the natural mature oak forest. Results of both the ordination and the quantitative character species analysis also confirmed that reforestation with native oak after mechanical soil treatment had detrimental effects on both studied ground-dwelling arthropod groups. The diversity and composition of ground beetles with high dispersal ability and less specific feeding habit recovers after the closure of the canopy, while similar recovery do not occur regarding millipedes with low dispersal ability and specific feeding habit. Our results suggest that soil preparation and light tilling should be omitted during the reforestation and cultivation of the reforested stands.

Growth and yield of two grain crops on sites former covered with eucalypt plantations in Koga Watershed, northwestern Ethiopia

Farmers in the highlands of Ethiopia often plant Eucalyptus on their farmlands. However, growing Eucalyptus, especially on farmlands suitable for crop production has become a great concern due to its alleged long-term site effects. Our study was conducted at Koga watershed, Mecha District, northwestern Ethiopia to investigate whether croplands afforested with Eucalyptus camaldulensis Dehnh. can be restored for annual crop production after tree harvest. We compared growth and yield of two agricultural crops, barley (Hordeum vulgare L.) and finger millet (Eleusine coracana (L.) Gaertn.), grown in clear-felled stands of E. camaldulensis and continuously cultivated croplands at twelve paired farmlands under a conventional farming system. Plant height and dry matter production were evaluated as indices of crop growth, while grain weight was evaluated as an index of crop yield. Crop growth and yield measurements averaged over all farmlands differed between land-use types. For both crops, plants grown on clear-felled stands were taller than on croplands. Dry matter production and yield were also significantly greater in crops cultivated on clear-felled stands. Cropland aboveground and belowground dry matter productions were lower by 31.8 and 25.4% for barley and 32.8% and 37% for finger millet, respectively. Clear-felled stands gave an average yield of 2.91 t·ha−1 for barley and 3.27 t·ha−1 for finger millet while cropland gave a yield of 1.97 and 2.31 t·ha−1 for barley and finger millet, respectively. Farmers also responded that farm plots on former eucalypt plantations showed greater crop growth and yield than did continuously cultivated croplands. Farmers perceived that Eucalyptus plantations improved soil fertility and they preferred clear-felled stands for crop production and wished to plant Eucalyptus on their farmlands. Our results suggest that conversion of agricultural lands to Eucalyptus plantations can increase post-felling yields of cereal crops.

Effect of <i>Eucalyptus camaldulensis</i> stand Conversion into Crop Production on Growth and Yield of Maize: the case of Koga Watershed Areas in northwestern Ethiopia

Farmers in the highlands of Ethiopia commonly plant eucalypts on their farmlands. However, growing eucalypt is becoming a great concern due to its alleged long-term site effect. In view of this, a study was conducted in Koga watershed, northwestern Ethiopia, to investigate whether croplands afforested with Eucalyptus camaldulensis can be reused for annual crop production after its removal. In this study, we compared growth and yield of maize between adjacent clear-felled E. camaldulensis stands and continuously cultivated farms at three paired sites. Plant height, leaf area, dry matter production and grain weight were evaluated as parameters for maize growth and yield. Maize plants grown on clear-felled eucalypt stands were taller and developed larger leaf areas than those grown on continuously cultivated farms. Dry matter production and grain yield were also significantly higher in maize plants established on clear-felled eucalypt stands. Farmers also responded that the growth and yield of maize grown on the clear-felled eucalypt stands were better than those grown on continuously cultivated farms. The results suggest that contrary to the popular belief, agricultural lands afforested with eucalypts can be re-used for annual crop production.Keywords: Clear-felled stands, Croplands, Crop performance, Farmers’ perception, Ethiopia.

Short-term changes in belowground C, N stocks in recently clear felled Sitka spruce plantations on podzolic soils of North Wales

There is currently only limited understanding of the influence of conifer plantation management on soil carbon (C) and nitrogen (N) storage in maritime Europe. The study reported herein examined the effect of clear felling on belowground C and N stocks, and CO2 effluxes at paired clear-felled, and standing plantation sites in North Wales. Clear-felled conifer stands were compared in three different time lapses (3, 5 and 8years after harvesting). The O horizon (and associated C) was completely absent on the year 3 and year 8 clear-felled stands. There was no significant influence of clear-felling on mineral soil C and N at 0–10cm depth between clear felled and unharvested sites, however, differences were observed in subsoil depths (10–20cm and 20–50cm). Clear-felled sites exhibited an initial gain in surface soil C and N through year 5 (likely due to incorporation of the O horizon into the mineral soil) after which the C stock decreased by year 8. Approximately 50Mg C and 3MgN ha−1 yr−1appear to have been lost from mineral soils 7years after clear felling. Clear felling significantly (p<0.05) increased soil CO2 efflux and soil surface temperature. Total CO2 emission from soils at clear felled sites was 148% higher than that of uncut plantations. Alternative harvest strategies should be considered that reduce C losses from plantations in North Wales.

Conservation of Heathland Ground Beetles (Coleoptera, Carabidae): The Value of Lowland Coniferous Plantations

The value of conifer-dominated plantation forestry for heathland carabids is examined, in Breckland, eastern England. Historically dominated by heathland habitats supporting scarce species of restricted distribution within the UK, approximately 47% of Breckland was afforested in the early 20th century. The carabid fauna of this forest, previously little known, was sampled by intensive pitfall trapping, and results compared to samples from heathland and arable. The results affirm that Breckland supports many range-restricted carabid beetles, including scarce species restricted to lowland heathland or sandy habitats. Approximately half of the heathland-associated species, and also half of the Nationally Scarce carabid species recorded in Breckland, were found within the forest landscape. Carabid species composition differed between closed-canopy forest, heathland and arable, while open forest habitats (clear-felled stands, young restocked stands, and track margins) contained a diverse fauna with elements from all habitats. The proportion of heathland-associated species was significantly greater in open forest habitats than in closed-canopy forest and was similar to that of heathland assemblages. Wing morphology did not differ between heathland species solely recorded from heathland and those also recorded in the forest. Nationally Scarce species from the forest had a wider UK distribution than those recorded only from heathland. Our study shows that, within conifer forest planted in lowland heathland areas, open habitats provided by trackway networks and clear-felling management can have significant value for the conservation of open-ground carabids, including species of conservation importance.