Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Planting trees on agricultural land either as farm woodlands or agroforestry (trees integrated with farming) is one option for reducing the level of atmospheric carbon dioxide. Trees store carbon as biomass, and may increase carbon storage in the ground. A review of the literature outlined uncertainty relating to changes in carbon storage after planting trees on agricultural land. The aim of this thesis is to deter¬mine the impact of tree planting on arable and pasture land in terms of above and belowground carbon storage and thereby address these uncertainties, and assess the implications for the Woodland Carbon Code: a voluntary standard for carbon storage in UK woodlands. Measurements of soil organic carbon to a depth of 1.5 m were taken at two field sites in Bedfordshire in the UK: a 19 year old silvoarable trial, and a 14 year old silvopasture and farm woodland. On average 60% and 40% of the soil carbon (rel¬ative to 1.5 m) was found beneath 0.2 and 0.4 m in depth respectively. Whilst tree planting in the arable system showed gains in soil organic carbon (12.4 t C ha−1 at 0–40 cm), tree planting in the pasture was associated with losses of soil organic carbon (6.1–13.4 t C ha−1 at 0–10 cm). Evidence from a nearby mature grazed woodland indicate that these losses may be recovered. No differences associated with tree planting were found to the full 1.5 m, though this may be due to a lack of statistical power. Measurements of above and belowground biomass, and the root distribution of 19 year old poplar (Populus spp.) trees (at the silvoarable trial) and ash (Fraxinus excelsior) trees ranging from 7 to 21 years (at several field sites across Bedfordshire) were made, involving the destructive harvest of 48 trees. These measurements suggest that Forestry Commission yield tables overestimate yield for poplar trees grown in a silvoarable system. An allometric relationship for determining ash tree biomass from diameter measurements was established. The biophysical model Yield-SAFE was updated to take into account root growth, and was parameterised using field measurements. It was successfully used to describe existing tree growth at two sites, and was then used to predict future biomass carbon storage at the silvoarable trial. Measurements indicate that losses in soil carbon at relatively shallow depths can offset a large proportion of the carbon stored in tree biomass, but assessing changes on a site by site basis may be prohibitively expensive for schemes such as the Woodland Carbon Code.

Student Number : 0318769R - PhD thesis - School of Geography, Archaeology and Environmental Studies - Faculty of Science / This thesis is about the relationship between planned resettlement, livelihoods and environmental resources in Zimbabwe. In Zimbabwean resettlement areas, assets such as human and physical capital, social networks and financial resources are often clearly insufficient to adequately provide inputs for the sustainable productive and extractive systems that are required to drive the rural economy. Due to uncertainties related to agricultural production doubts have been expressed about the benefits of state sponsored resettlement. Currently, debate is raging on whether land resettlement in Zimbabwe has yielded the intended benefits among land reform beneficiaries, with some scholars even questioning whether state sponsored resettlement is not merely an expensive way of reproducing the livelihoods of communal lands. This thesis contributes to the ongoing debate about the link between rural livelihoods and land resettlement, using the case of Mufurudzi resettlement scheme in Zimbabwe. Based on a livelihood framework, the thesis argues that in order to fully understand the relationship between land reform and livelihoods, livelihood trajectories have to be examined. In line with this thinking the thesis presents a number of arguments. First, the thesis argues that there are many theoretical frameworks for analyzing the relationship between people, resettlement and environmental resources such as forests and woodlands and the sustainable livelihood framework is just one of them. Second, resettlement does not necessarily always lead to environmental destruction. Instead resettlement provides the mechanism for unlocking the natural capital that local communities require for survival. Forest and woodland resources are one such form of natural capital. Under these circumstances access to natural capital, particularly in the form of forest and woodland resources, becomes the cornerstone of survival, notwithstanding the role that these resources play in supplying daily livelihood requirements such as food, shelter, fuel, medicines and other needs, in a harsh macro-economic environment. Apart from providing important products, forest and woodland resources also provide a mechanism through which land reform beneficiary communities can diversify their livelihoods. The key finding of this research is that despite their continual use during the past 25 years no wholesale degradation has occurred to the forest and woodland resources in Mufurudzi. Informal CBNRM is responsible for this situation.

The extent and quality of forested habitats have changed across Europe and as a result many forest species have suffered declines and range contractions. European legislation has been introduced to conserve those species that have been negatively impacted by widespread land-use changes. In order to assess the needs of declining species and the efficacy of these protective measures, the effects of habitat type, configuration and management on individuals and populations needs to be understood. In this thesis, I have investigated patterns and drivers of variation in the status of populations of hazel dormouse Muscardinus avellanarius in the United Kingdom. I have assessed the effects of variation in habitat on hazel dormice at multiple spatial scales, and related this to woodland management.

Current and emerging threats to trees and forest ecosystems require a re-evaluation of the way forest genetic resources are managed. Governments in the United Kingdom and elsewhere are committed to the restoration, expansion and creation of new woodlands. Tree populations are often adaptively differentiated from one another, so a key question underpinning the success of planting schemes is the choice of seed origin. A long held understanding is that locally sourced seeds will have the best opportunity to tolerate conditions of the planting site (local provenancing). However, the rate at which the environment is changing introduces a great deal of uncertainty into decision making and there is concern that climate change is proceeding at rates faster than those with which locally adapted trees would be able to cope. As such, there are suggestions that seed collected from areas already experiencing the anticipated future conditions will improve the adaptability of forests (predictive provenancing). This thesis investigated outstanding questions relating to the merits of the local provenancing and predictive provenancing approaches, and the practical implementation of seed sourcing policy in British forestry. The validity of existing seed zone boundaries used under local provenancing was analysed for ancient semi-natural Scots pine Pinus sylvestris L. forests of Scotland. Vegetation description and analyses of climatic covariates revealed that the existing series of seed zones used to guide selection of planting stock for restoration do not necessarily environmentally match seed sources to planting sites under current conditions. Additional disparity is introduced when edaphic variation (or proxies for this) is considered. To determine whether future adaptation under local provenancing may be restricted by limited pollen flow among populations of native Scots pine in Scotland, the timing of pollen production in five populations was estimated by repeatedly measuring strobilus development on a series of twenty trees over three consecutive springs. Differences in the mean predicted date of pollen production were found, with populations in the warmer west shedding pollen earliest each year, although the timing and differences in timing among populations varied from year to year, with shedding taking place earliest in the warmest of the three years and latest in the coolest year. A theoretical multi-patch, ecological genetic individual-based model (IBM) was developed to investigate the utility of different seed sourcing strategies (local versus non local provenance) and their capacity to help populations adapt to directional climate change. As well as being adapted to climate, which varied in a clinal pattern, individuals also had to be well adapted to the habitat conditions of the planting site in order to survive hard selection at the seedling stage. The model showed that population size of a new planting was reduced when planting stock adapted to the future conditions but not to current conditions was deployed. The differences were most severe when selection acted simultaneously on both the climate-related and the habitat-related phenotype. Finally, a series of in-depth qualitative surveys conducted with members of the domestic forest nursery and seed supply sector in Great Britain found that there are many difficulties associated with seed sourcing and the supply of trees. These problems arise due to a very limited ability to predict demand at the time of seed sowing, and lead to waste when demand is overestimated and importation of planting stock when demand is underestimated. Confidence and competitiveness in the domestic sector could be greatly improved by updating seed sourcing guidelines and by simplifying certain aspects of the process by which forest planting projects are funded.

The archaeological record varies with the fluvial style and sedimentation of a river, thus controlling the location, preservation, and recognition of archaeological sites. This project identifies archaeological site patterning and preservation along a fluvial system in Iowa that has been relatively stable since the last glaciation. The Upper Des Moines River in Iowa formed approximately 12,500 yr. cal BP as an englacial channel routing glacial meltwater south along the Des Moines Lobe. During the last glacial retreat, the channel incised forming what is now called the High Terrace (TH). Early post-glacial occupations in Iowa would have had access to this the high terrace and uplands. Thus, the Paleoindian and early to middle Archaic site distributions along the Upper Des Moines River are found in upland and upper terrace locations. The intermediate terrace (TI) formed between 4000 and 1000 yr. cal BP and represents the elevation of the river flood plain during this period. Late Archaic people had access to this surface as well as the TH and uplands. By 1000 yr. cal BP, the Upper Des Moines River had eroded down to bedrock and established a floodplain at the level of the lower terrace. Subsequent erosion produced the modern channel configuration with an established series of dated terraces (High Terrace (TH), Intermediate Terrace (TI), and Low Terrace (TL)). The Woodland period peoples would have had access to the current/modern fluvial landscape. To assess site locations strategies of populations that inhabited the Upper Des Moines River valley in the Holocene, 721 archaeological sites were examined and classified using site reports and artifacts as Paleoindian, Archaic, Woodland, Historic and Unknown. The sites were then mapped and associated with geomorphic features in the valley. As expected, Paleoindian sites and Early to Middle Archaic sites were all located on the upper terrace and uplands because the intermediate and lower terraces had not yet formed. Late Archaic people had access to the floodplain that formed intermediate terrace as well as the uplands and upper terrace. Woodland period sites occurred on high (upland and TH), intermediate (TI), and low (TL and floodplain) elevation landforms along the river. The study demonstrated there was a preference for burials/ceremonial sites being placed at higher elevations (TI and higher) and habitation sites being placed at lower elevations (TL and current floodplain) near the main river channel.

A study of habitat selection by large wild ungulates was carried out on a 50 cm2 area in the sub-tropical Lowveld region of eastern Transvaal province, South Africa. Estimations were made of herbaceous forage net productivity and ungulate secondary productivity on the same area. Fourteen vegetation types, varying in composition and structure from open savanna to dense woodland, were delineated by association analysis. Structural and vegetational characteristics which were considered to influence ungulate distribution were measured within each vegetation type. The study area supported resident populations of seven ungulate species during the wet season; drv season densities were higher due to population influxes from surrounding areas. Densities ranged from 13 to 67 animals per km2, with impala making up from 40 to 70 percent of the total population, wildebeest 10 to 40 percent, and lesser proportions of giraffe, zebra, kudu, warthog and waterbuck. Savanna vegetation types supported total densities of up to 185 animals/km2, while wooded types support fewer animals. Waterbuck were the most selective of the ungulates and concentrated mainly in the riparian woodland. Wildebeest, zebra and giraffe made variable use of savanna and open woodland types. Warthog preferred savanna types and avoided woodland. Impala were less selective, and kudu showed no habitat preferences. Ungulate distribution was related to several habitat characteristics, and the key factors were found to differ in each case. Each species had a unique combination of habitat characteristics to which it responded in linear fashion, and this was considered to be the way in which ungulates avoided competition by achieving spatial separation. Herbaceous forage standing crops and net production were functions of vegetation composition, soil types, rainfall and extent of ungulate utilization. Standing crops ranged from 350 to 4104 kgs/ha air-dried forage. Net primary production ranged from zero to 2719 kgs/ha; vegetation types on sandy soils did not produce in years with poor precipitation. Ungulates consumed about one-fourth of the herbaceous net primary production during the wet season and more than four-fifths during the course of a full year. Ungulate biomass on the area averaged about 40 kg/ha during the wet season and 65 kg/ha in the dry season, but biomasses varied a great deal with vegetation type, ungulate population species coMposition and seasonal densities. Ungulate secondary product ion varied correspondingly and ranged from 1.3 x 10-3 kcal/m2 per day to 4.8 x 10-3 kcals/m2 per day. Overall secondary production rate for the 2-year study period was 0.97 kcals/m2 per year, produced from a mean standing crop of 7.46 kcal/m2.

This thesis examines the history and results of investigations at 1Cv32, the Mitchell Site, in Covington County, Alabama. The Mitchell Site is perhaps the largest recorded Middle Woodland mound center in southeast Alabama. Data from limited testing are examined here with particular emphasis on the ceramic assemblage. Ceramic data indicate that the portion of this site investigated is predominately Middle Woodland, with distinct Weeden Island attributes.

This research describes a large, newly-recorded archaeological site in the Upper Apalachicola River valley, northwest Florida, and a private collection of artifacts from it, as well as test excavations, three-dimensional modeling, clay/pottery sourcing through chemical analysis, and direct radiocarbon dating of ceramics to relate the site with regional archaeological chronologies and settlement patterns. A University of South Florida (USF) 2013 field school conducted excavations at the multicomponent midden on the western floodplain of the Apalachicola River called the McKinnie site (8JA1869). Students collaborated with a local collector and family members to learn about the site's history. Data from the collection and excavations show that the site was inhabited through four thousand years of prehistory, serving as a rich seasonal resource base for local people in the area starting in the Middle Archaic Period, and as a small place of occupation during the Woodland Period, until people moved out into the river valley to live in farming villages. We also investigated a series of fascinating features, stored in the private collection and excavated by USF, which may have been intentionally buried at the site up to 5500 years ago. They may be evidence of some ancient ochre processing to obtain pigments, or some other special activity.

The Crystal River site (8CI1) is a Woodland-period (ca 1000 B.C. to A.D. 1050) mound complex located on the Gulf of Mexico in west-central Florida. Among the features at the site are four shell and sand platform mounds, two burial mounds, and an extensive shell midden. The proximity to the Gulf and the reliance on marine and brackish resources present an apparent, yet poorly understood interaction between the people of this area and their environment. I attempt to model the relationship of the occupation of Crystal River with sea level change. The analysis of 58 soil cores from across the site provided detailed stratigraphic information and AMS radiocarbon dates needed to examine anthropogenic site formation. I then compared the rates of midden deposition and monumental architecture construction with sea level and climatic periods. This research revealed that landscape modification occurred during periods of both high and low mean sea level suggesting that human-environmental interaction at Crystal River cannot be modeled by sea level alone. Further comparison showed that mound construction increased and midden deposition decreased during the Vandal Minimum indicating a possible sociopolitical transition concurrent with changing environmental conditions.