Severely nitrogen and phosphorus deficient restored opencast coal mine sites planting with Sitka spruce ( Picea sitchensis , Bong. (Carr.)) were treated with both sewage sludge and inorganic fertilizer. Cake sludge was applied before planting at the rate of 100 and 200 tds/ha and liquid sludge at the rte of 227 m3/ha at the age of 3 in selected plots. The highest treatments (S200L) supplied approximately 2051 kg N/ha and 983 kg P/ha which is sufficient to establish an internal nutrient cycle in such degraded sites. Sewage sludge significantly increased the tree growth and foliage N and P concentrations both over the control and inorganic fertilizer treatments. Foliage N concentrations up to 1.95&'37 increased the maximum height growth above which the height growth declined due to excess N concentrations. Both the mean needle weight and height growth increased in response to the increased foliar P concentrations and the response is still not complete. Whole tree sampling showed that there was significantly more tree biomass in sludge treatments in comparison to the control treatments. Regression equations based on independent variables of stem diameter at 5 cm from the ground were developed to estimate total tree dry biomass. Ground vegetation dry matter, nutrient content and species diversity significantly increased in sludge treatments. Soil pH increased, bulk density decreased and organic C, total N, available P, K and Mg increased following sludge application in comparison to the control treatments. Nitrate leaching losses increased immediately after the liquid sludge applications in highest sludge treatments but with time fell down and remained within the standard limit for potable water. Drain water nutrient leaching losses remained well below the soil leachate except for magnesium. Nitrogen mineralization potential increased with increased application rate indicating increased cycling of N within the ecosystem and hence long-term growth response potential to the applied treatments.

Tropical forests contain the greatest biotic diversity of any biome, and those of South-east Asia are amongst the most diverse and tree species rich. I studied the speciose understorey tree genus, Aporosa (Euphorbiaceae), at two c. 50 ha plots in Malayisa, at Lambir Hills National Park, Sarawak, and at Pasoh Forest Reserve Peninsular Malaysia, where 17 and 12 species co-occur, respectively. The aim of this study was to determine which factors influence the spatial distribution of Aporosa species, what limits their abundance, and ultimately what are the mechanisms of coexistence among the species of this genus. Using a method of second-order spatial pattern analyses based on Ripley's K function to test for non-random spatial distributions, and to test for spatial associations between species (using a bivariate method) I found that Aporosa species formed spatially distinct assemblages at both sites. A randomization procedure suggested that these assemblages were explained by biases in the distribution of species in relation to habitat types. Soil type, as determined by parent material, was an important determinant of habitat preferences, although topography and forest stmcture also accounted for some variation. I found measurable effects of position on soil and especially topographic types on mortality and recruitment rates of many Aporosa species. Growth rates over a 5-8 year period varied between species, but, perhaps due to the short time interval and the correlation between abiotic variables, they were a poor indicator of habitat preference as defined by bias in a species' distribution. Aporosa species exhibit a range of morphological, anatomical and biochemical properties, and I found evidence that both habitat partitioning and density-dependent mortality of juveniles occurred. These are both mechanisms contributing to the maintenance of species richness. A severe drought had differential effects on mortality rates of Aporosa species and may be important in determining species' spatial distributions and abundance. Therefore disturbance events are also likely to be important mechanisms, as are non-equilibrium random population fluctuations, between ecologically similar species.

The establishment of native woodland in the moorland areas of upland Britain is increasing. However, there is no clear basis on which to predict either the effect of this on the ecology of the mountain hare, or the effect of mountain hare on woodland establishment. This study investigates the feeding ecology of the mountain hare, a primarily moorland inhabitant in upland Britain, in an upland landscape containing a newly established native woodland and also the potential impact that they may have on regeneration of native woodland species (Pinus sylvestris, Betula pubescens and B. pendula). The mean home range size, determined by radio-tracking, of male mountain hares was 12.1 ha and females 8.9 ha. The native woodland habitat was not preferentially selected by mountain hares in summer or winter. Faecal n-alkane and long-chain fatty alcohol analysis revealed that P. sylvestris and B. pubescens were minor components of the diet in all seasons. The diet of both male and female hares was dominated by Calluna vulgaris in winter and by grasses, sedges and rushes in summer. Annual measurements of browsing by mountain hares on P. sylvestris and B. pendula saplings at eight sites throughout Scotland, showed that on average only 5.8 % of trees sustained browsing each year. Relative hare abundance, tree density, tree species and ground vegetation height did not predict the extent of browsing damage by mountain hares. In contrast, a field-based planting experiment involving nursery grown B. pubescens saplings, had higher local hare densities and revealed that mountain hares do browse saplings extensively and that season, tree density and ground vegetation height are important in determining the extent of browsing. Seasonal habitat utilisation of the experimental plots by mountain hares fluctuated in relation to the frequency of browsing. In general, the results showed that moderate densities of mountain hares are unlikely to inhibit regeneration of native woodlands However, the likelihood of damage will increase if trees occur at high densities and if local hare density is high.

Windthrow is a major influence on silvicultural practice in the UK. Profitability is reduced by the need to fell plantations prematurely. In recent years there has been much debate on the role of spacing and wide- spacing, or respacing has been advocated as a means of improving stability. This debate has lacked quantitative evidence. The purpose of this study was to assess the factors involved in tree stability and to use the results to. investigate the influence of spacing and stability. Using the approach of Petty and Worrell (1981) stability was first considered as a static model. The factors involved are the within canopy wind profile, the stem and crown weight distribution of the trees, the deflection curves assumed by the tree in response to wind loading and the maximum turning moment causing stem breakage or uprooting. Investigation of the influence of spacing on the resistance of Sitka spruce trees to stem breakage and uprooting showed that the maximum turning moment was positively related to the stem weight, dbh3 and dbh/wt. There was no evidence to suggest that the relationship between the maximum turning moment and the independent variables differed between spacings. Analysis of data from Forestry Commission tree pulling experiments revealed that on sites where stem breakage and uprooting occurred the turning moments causing stem breakage and uprooting were similar. The deflection curves of five Sitka spruce trees, growing on a brown earth site, were measured and compared with the theoretical deflection curves devised by Petty and Worrell (1981). The theoretical curves gave reasonable approximations to the actual curves for small deflections. Most of the experimental work was undertaken at the Forestry Commission's experimental area in Moffat Forest where equipment was installed for the monitoring of airflow above and within the forest canopy and of the tree response. Using Forestry Commission data the within canopy wind profile was obtained. Ten Sitka spruce trees were loaded until failure and the stem deflection curves, stem and crown weight distributions and the turning moments causing soil failure and uprooting were measured. The theoretical stem bending curves gave good approximations to the actual curves until soil breakage occurred. Following soil breakage two samples were released and repulled and, although the maximum resistance and the deflection at this point were unaltered, the initial force per unit deflection was halved. The critical wind speeds to cause uprooting were calculated using measured wind profiles and assuming static loading of the crown. Values obtained greatly exceeded the wind speeds recorded during a gale which caused damage. The damping ratios of the 3 trees bearing accelerometers were measured with and without crown contact. For the 2 dominants canopy contact had less effect on the damping ratio than the sway direction whereas for the subdominant the canopy treatment had the greater effect. Recalculation of the critical wind speeds of the ten tree pulling samples, using the damping ratios estimated for the accelerometer trees, and assuming a resonant response reduced the values to within the range of measured gusts recorded during a gale. Displacements of the 3 accelerometer trees, estimated from accelerometer data, were compared with simultaneous wind speed recordings. Perfect resonance was not observed but very large oscillations were noted to build up over a period of 2-3 cycles. The larger gusts (?10m m s-1) tended to produce a static response and to be responsible for the initial deflection whilst subsequent smaller gusts tended to cause the dynamic responses. In order to predict the critical wind speeds causing damage it is necessary to take this dynamic interaction into account. Theoretical stability calculations for unthinned plantations at spacings of 2.0m, 2.4m and 3.0m showed that for static loading the increase in the resistance to uprooting or breakage as a result of increasing mean tree size outweighed the greater drag force on the crown. The wide spaced stand retained its stability advantage even for resonant wind speeds. However, small changes in the within canopy wind profile and the resistance of the trees to uprooting/breakage removed the advantage gained by the wider spacing. More information is required on the influence of spacing on the dynamic response of trees to wind loading before increasing the spacing can be said to improve stability on wet soils.

This study describes the population genetic structure of Milicia species sampled from different provenances distributed over 5 countries (Sierra Leone, Cote d'Ivoire, Ghana, Cameroon and Tanzania). Random amplified polymorphic DNA (RAPD) and inter sample sequence repeats (ISSR) variation in 41 accessions from 5 different populations were consistent with each other. Analysis of molecular variance partitioned RAPD and ISSR variation into within- and between-population components. The between-population variation component was large, accounting for 62.2% and 71.5% for RAPD and ISSR respectively. Dendrogram analysis produced 2 major clusters separating dry zone accessions (mainly M. excelsa) from moist/wet zone accessions (mainly M. regia). Sub-clustering further separated accessions by forest type and/or geographic region. Phylogenetic analysis of chloroplast genes involved the use of nucleotide sequencing, restriction fragment length polymorphism (RFLP), and microsatellites. Only one region (5' to trnS) out of 6 regions analysed was polymorphic and revealed 3 different cytotypes. The distribution of the cytotypes matched with the 2 major clusters produced by the dominant markers. Wet/moist and dry zone bands were identified with little evidence of gene flow between populations. Seed mediated gene flow estimated from the chloroplast analysis was small (Nm = 0.23). To relate these molecular information with Phytolyma resistance, field provenance and progeny trials were conducted. Accessions from wet/moist zones were more tolerant to Phytolyma than accessions from dry zone. The data also suggest that accessions bearing the wet/moist zone specific markers have a high probability of being tolerant to Phytolyma. The approaches outlined and the results have general applicability in the sustainability of Milicia spp. and are discussed in relation to germplasm sampling, management and conservation of genetic recourses of Milicia species.

No description available.

During the last fifteen years the landscape of the Vale do Alto Tâmega, a region in Northern Portugal, has been subjected to environmental pressure leading to a change in land cover from predominantly forest to a mixture of shrub and rock outcrops. Both natural (e.g. wild fires) and anthropogenic (e.g. timber harvesting) factors have contributed to this change. Practical management techniques are necessary to preserve and manage this important environmental resource. New technologies, such as Geographical Information Systems (GIS), the Global Positioning System (GPS) and Remote Sensing (RS) provide tools that can be used for forest management and wild fire protection. This thesis explores the suitability of these technologies for managing forests located in the Vale do Alto Tamega region. It focuses on the development of data sets and models that can be used to assess the susceptibility of forests to fire hazards. The GIS analysis reveals that more than half of the study area presents a high fire hazard and nearly a third of the Pinus pinaster stands were burnt between 1986 and 1995. The GIS results also show that much forest land is occupied by unsuitable species (e.g. coniferous instead of deciduous trees), which contribute to restricted timber production and a high fire hazard. GPS was used to survey both the location of sampling plots and to map the boundaries of burnt areas or of post-fire recover areas, associated with traditional forest mapping and measurement techniques. These data were then used to update GIS and to support satellite image classification. Remote sensing derived data were used for mapping, providing up¬to-date land cover maps, and to derive predictive relationships which can be used to estimate forest biophysical variables (e.g. Leaf Area Index or Biomass) that can be used by forest managers. The results of the research demonstrate that GIS, GPS and RS could be used together in forest management and protection, such as in the classification of the land cover in order to calculate fire hazard indices or in the analysis of forests dynamics.

Agriculturally-altered habitats, especially oil palm plantations, are rapidly dominating the Southeast Asian landscape. Although recent studies have shown reduced species diversity associated with this commodity, data on amphibian diversity are rare. The following thesis explores the impact of oil palm plantations on amphibians in Peninsular Malaysia based on (1) amphibian biodiversity, (2) quality and use of breeding sites, (3) habitat use and (4) parasitism. Contrary to expectation, not all metrics of biodiversity differed between oil palm plantations and secondary forest sites. Amphibian community composition, however, differed greatly between the two habitat types, with oil palm communities being dominated by species known to prosper in disturbed habitats, indicating that the community is currently of limited conservation value. Within plantations, temporary pools were found to serve as important breeding habitats for amphibians so a focused study on the characteristics of these pools was carried out. Although we found differences between pools, the proportion of occupied pools did not differ significantly between plantation and forest sites. I did observe evidence of breeding site preferences of least concern, plantation amphibians, along with habitat partitioning between species, a similar pattern also seen in forest communities. I compared parasite burdens between habitats by screening for the fungus Batrachochytridium dendrobatidis (Bd) and for nematode parasite load. Bd was not detected in any of my samples and there was no difference in nematode loads between habitat types. However, patterns of nematode prevalence was affected by host type, while nematode intensity was dependent on an interaction between host and body size. The final chapter indicates that in terms of parasite, the host environment is the most important. Additionally, differences in host-parasite patterns between habitats indicate a possible underlying problem that rapid biodiversity censuses would be unable to detect.

In recent years, interest in uneven-aged forestry has been increasing in Britain, particularly for sensitive areas such as recreation and amenity forests. Literature on the economics of uneven-aged forestry is scarce and few operational, uneven-aged forests are available for study. Therefore, in order to quantify the operating costs associated with uneven-aged forestry, a modelling approach was chosen. The resulting model is written in FORTRAN and uses a series of square two-dimensional arrays to represent a block of forest. The block may then be managed by clearfelling and replanting at a specified age, or by a system of group management with a choice of four group sizes. The resulting model was then used to investigate the effect of the following management strategies on operating times: 1. Varying the scale of working (i.e. the group size and forest size) in the uneven-aged forest. 2. Using shortwood or pole-length harvesting systems and a range of machine types within each harvesting system. 3. Varying the length of time taken to transform the structure of the forest from even-aged to uneven-aged. 4. Varying the age of the trees when the transformation from even-aged to uneven-aged structure begins. The results obtained from running the model show that the time taken to carry out an operation is influenced both by the absolute size of the group within the forest block and by the number of groups of that size within the forest block. This fragmentation effect explains why it is difficult to determine the absolute costs of working for a specific group size, because it is the combination of group size, number of groups and forest block size, which determines costs. Most of the results below are based on a range of group sizes from 1.000 ha. to 0.0625 ha., with a block size of 16 ha. Forwarders were penalized when the group size was decreased to 0.0625 ha. (-12% increase over clearfelling), because very small groups do not contain full forwarding loads and a large proportion of total forwarding time is spent manoeuvring into and out of groups. However, the operating times for the three group sizes 1.00 ha., 0.25 ha. and O. 1 1 ha. were very similar indicating that the group size can be quite small before any extra forwarding costs are incurred. On poor sites, the cost differential between the largest and smallest groups is greater. In contrast to forwarding, skidders are most penalized with the decision to adopt an uneven-aged system, and once that decision has been made, there is not a clear increase in costs with decreasing group size. During the transformation period, felling and thinning times in the uneven-aged system are significantly higher than those for the even-aged system, because trees are being harvested prematurely to create the early groups, but this difference is reduced once the forest is transformed. Felling and thinning times increase gradually as the group size decreases, because more care is needed for the felling operation and more time is needed for snedding coarse edge trees. Replanting times for the uneven-aged forest are approximately 8% - 14% higher than replanting times for clearfelling. The results from the model were then analysed using the EXCEL spreadsheet programme to examine, among other things, the cost implications of varying group size, and the relative profitability of uneven-aged and even-aged management. First,optimum ages to begin transformation were found, which varied with the Yield Class and discount rate chosen. Then, the effect of the length of the transformation period was examined and a long transformation period (80-years) was found to be preferable to a short transformation period (40-years). The analysis showed that at high discount rates even-aged and uneven-aged management had similar Net Present Values, but at lower discount rates the even-aged system was preferred. The greatest financial penalty was incurred with adoption of an uneven-aged system, and reducing the group size had relatively little impact on Net Present Values. Other costs and benefits, such as scenic beauty and recreation potential, could not be included in the model, because research relating these values to forest management variables has not been carried out. Therefore, these mostly non-financial factors were discussed for even-aged and uneven-aged forestry, based on a review of the literature.

This study seeks to investigate whether the biodiversity conservation of the Sinharaja rainforest in Sri Lanka can be economically justified solely in terms of its non-timber forest products (NTFPs) extraction potential as claimed by some recent research. A variety of methods and techniques were deployed including a botanical inventory survey, a crosssectional ethnobotanical survey, an ethnobotanical log-book survey and an ethnozoological survey. Several aspects relating to the NTFPs use: a) valuing the total inventory stock, the total extractable stock limit, the potential flow and actual flow; b) estimating the wild meat flow; c) seasonality of harvesting; d) sustainability issues; e) influence of phytosociological characteristics; f) influence of socio-economic characteristics; and g) forest accessibility; and h) market accessibility were investigated. Biophysical and socio-economic factors influencing the NTFPs value were investigated using a regression analysis. The impact of the NTFPs extraction on the regeneration of the natural population was investigated using three forest sites, a proximal site, a distant site, and a logged forest. The local peoples' perception about the sustainability of NTFPs harvesting was analysed using logit regression analysis. A geographic information system was used to investigatet he influenceo f accessibilityt o the forest and to the marketplace from the villages on the forest products flow. Finally, the NTFPs value was compared with alternative land-clearance use and timber use values. The results indicate that the NTFPs extraction value is insufficient on its own to economically justify the rainforest biodiversity conservation in Sri Lanka, and perhaps elsewhere. There is also some doubt about the long term sustainability of forest products extraction. The study concludes that the rainforest conservation will have to be justified by a full total economic value (use and non-use values) appraisal, together with other scientific and ethical reasoning and cannot be promoted solely on the basis of non-timber extraction value.