The sustainability of selection cutting in a late successional broadleaved community forest in Bhutan

This study assessed the sustainability of selection cutting in a community forest (CF) in Bhutan. The harvesting approach differed from cable crane logging operations in an adjacent commercially managed forest by creating much smaller canopy openings. This had many implications for natural regeneration of preferred species. The study was conducted in a late successional broadleaved CF containing 32 genera of tree species dominated by Quercus and Castanopsis and managed for timber, firewood, non-wood forest products and forest grazing. The study was based on a comparison of two forest inventories to assess forest structure and regeneration, a study of stumps to quantify harvesting intensities, and a household survey to quantify livestock holdings and grazing patterns. The study examined different intensities of selection cutting in three blocks of the CF and found that higher intensities of selection cutting did not have a negative impact on: (a) natural regeneration of seedlings and saplings of preferred timber species; (b) the diameter distribution of all species and use categories except for Quercus; (c) the diversity of tree genera; and (d) the percentage of remaining trees with favorable bole shape and form. These results contrasted with findings in the adjacent commercially managed forest. Community management of broadleaved forests with selection cutting appeared to be sustainable and avoid some of the unresolved silvicultural problems associated with commercially managed forests in Bhutan. However more research is needed on the sustainable management of Quercus spp.     

Andic properties in soils developed from nonvolcanic materials in Central Bhutan

A number of soils are described in the literature as having andic and spodic soil properties, but have developed in nonvolcanic and nonallophanic materials and lack typical Podzol eluvial and illuvial horizons. They cover a wide range of parent materials and different types of climate. They have always been regarded as restricted to small areas. They were assigned to Andisols/Andosols, Podzols/Spodosols, or andic Inceptisols in the WRB and Soil Taxonomy and sometimes also named Cryptopodzols or Lockerbraunerden. Recent soil surveys in Bhutan, E Himalayas, show these soils are widespread at altitudes between 2200–3500 m asl and are spanning several bioclimatic zones. The aim of this study is the detailed characterization of specific properties and processes of formation by physical and chemical analyses, NMR spectroscopy, column experiments, SEM, XRD, and ¹⁴C dating in one of these soils in E central Bhutan. The results indicate advanced soil development with high amounts of oxidic Fe and Al compounds, low bulk densities (partly <0.5 g cm^–3), P retention >85%, and a dominance of Al‐hydroxy‐interlayered phyllosilicates. Scanning electron microscopy of sand fractions indicate microaggregates highly resistant to dispersion. Column experiments show podzolization with mobilization and translocation of DOM, Fe, and Al. Nuclear‐magnetic resonance spectroscopy and ¹⁴C ages of 16,000 BP indicate stabilization of DOM. Applying classification criteria, these soils appear to have andic and spodic features, but are neither Andosols nor Podzols senso strictu. Especially the role of Fe seems to be underestimated with regard to the specific soil‐forming processes. Because of their widespread occurrence and distinct properties, we suggest either a simplification of the criteria for existing soil types or a clearly defined separation of volcanic and nonvolcanic/nonallophanic Andosols.     

Identification of Armillaria isolates from Bhutan based on DNA sequence comparisons

Armillaria root rot is a serious disease in fir and mixed conifer forests of Bhutan, Eastern Himalayas. The species causing this disease have, however, never been identified. The aim of this study was to identify field isolates collected at four localities in Bhutan. Identification was based on RFLP analysis of the IGS-1 region, comparisons of ITS and IGS-1 sequence data with those available on GenBank, cladistic analyses and sexual compatibility studies. Isolates were found to reside in two distinct RFLP groups. RFLP group 1 isolates from Pinus wallichiana at Yusipang had RFLP profiles and IGS-1 sequences similar to those of Armillaria mellea ssp. nipponica . Although ITS sequence data are not available for A. mellea ssp. nipponica , sequences from this DNA region were most similar to the closely related A. mellea from Asia. The RFLP profile and IGS-1 sequences for RFLP group 2 isolates from Abies densa at Changaphug, Tsuga dumosa at Chimithanka as well as Picea spinulosa and T. dumosa in the Phobjikha valley were similar to those published for Armillaria borealis , Armillaria cepistipes , Armillaria gemina and Armillaria ostoyae . Distance analysis based on IGS-1 and ITS sequence data indicated that these isolates are closely related to A. cepistipes , Armillaria gallica and Armillaria sinapina . The isolates were, however, sexually incompatible with tester strains of A. cepistipes , A. gallica and A. sinapina . Although closely related to these species, they appear to represent a distinct taxon that will be referred to as Bhutanese phylogenetic species I (BPS I) until basidiocarps are found and the species can be described.     

Livestock predation by carnivores in Jigme Singye Wangchuck National Park, Bhutan

Villages in Jigme Singye Wangchuck National Park, central Bhutan, report livestock depredation by wild carnivores including leopard (Panthera pardus), tiger (Panthera tigris), Himalayan black bear (Ursus thibettanus), and dhole (Cuon alpinus). In a survey of 274 households in six different geogs (sub-districts) within the park, 21.2% of households surveyed reported losses of a total of 2.3% of their domestic animals to wild predators over 12 months. This loss equated to an average annual financial loss equal to 17% (US$ 44.72) of their total per-capita cash income. Total reported losses during 2000 amounted to US$ 12,252, of which leopard and tiger kills accounted for 82% (US$ 10,047). Annual mean livestock loss per household (of those that reported loss) was 1.29 head of stock, equating to more than two-thirds of their annual cash income of $250. Lax herding, inadequate guarding practices, and overgrazing may have contributed to livestock losses. Approximately 60% of the households lacked proper stables for corralling their livestock at night and there was a significant correlation between the number of livestock lost and the distance between the household and the grazing pasture. Overall, reported predation rates have increased since the inception of the park in 1993 and since implementation of the Forest and Nature Conservation Act in 1995, which prioritises some of Bhutan’s key livestock predators for conservation. We propose livestock intensification programmes, including pasture improvement, and financial compensation as short-term measures to reduce conflict between people and predators. In the long-term, we recommend that the feasibility of an insurance scheme should be tested, the possibility of relaxing the resource use restrictions in the Forest and Nature Conservation Act of 1995 be explored, and that farmers should be involved in managing human-wildlife conflicts - particularly through improving their own herding and guarding practices, and building proper corralling facilities and adopting reliable corralling procedures.     

Experiences with tree fodders in temperate regions of Bhutan

Tree fodders are traditionally used in temperate and subtropical parts of Bhutan and provide approximately 20% of the fodder requirement of the country's livestock. Willow (Salix babylonica), Quercus semecarpifolia and Euonimus spp. were considered the most important species for temperate areas. Crude protein content of willow leaves decreased from 24.8.% in April to 11.3% in October. Bulls' voluntary intake was 77.7, 58.4, and 28.6 g DM/W^0.75 for willow, Popular robusta and Quercus semecarpifolia, respectively. Compared to temperate grasslands under the absence of phosphate inputs, tree fodders have a higher production potential and produce better quality fodder. Tree fodders may complement, but will not replace herbaceous fodder species in temperate areas. Assessment of yield potential in comparison to and in association with herbaceous temperate species is considered the most important research area.