No description available.

No description available.

No description available.

No description available.

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.

An experimental forest watershed, consisting of three small catchments at Berembun, Negeri Sembilan, in Peninsular Malaysia has been monitored from 1979 to 1987. Adequate instruments were installed for continuous collection of hydrologic and climatic data. The calibration and post-treatment phases lasted for three and four years respectively. Two types of treatments were imposed -namely commercial selective logging and supervised selective logging in catchment 1 and catchment 3 whilst catchment 2 remained as a control. Pertinent logging guidelines were prescribed and assessed in C3 in terms of hydrological responses. Significant water yield increases were observed after forest treatment in both catchments amounting to 165 mm (70%) and 87 mm (37%) respectively in the first year; increases persisted to the fourth year after treatment. Magnitude and rate of water yield increase primarily depended on the amount of forest removed and the prevailing rainfall regime and the increase was largely associated with baseflow augmentation. Interestingly, both types of selective loggings produced no significant effect on peak discharge while the commercial logging resulted in a significant increase in stormflow volume and initial discharge. Such responses can be explained by the extensive nature of selective logging which normally left a substantial area of forest intact and minimal disturbance to flow channels. Thus, conservation measures introduced in this study - the use of buffer strips, cross drains, an appropriate percentage for the forest road network,- were found to be effective and beneficial in ameliorating the hydrological impacts.

No description available.

Today, only 7 % of the Atlantic Rainforest, that once covered Brazil, remains scattered across the southern parts of the country. As the forest is rapidly disappearing, the government of Brazil has emerging interest of preservation. Thus more and more areas are turned into national parks and reserves. At the outskirts of one of these reserves, the Iracambi research station is situated. The center makes an effort to carry out applied research to find methods of preserving and learning about the forest. It is within that context the project described in this report has been performed. The project aimed to establish a water balance over Graminha Basin, the main river in the Iracambi research area. By doing this the understanding of the fluctuations of the amount of water in the ecosystem could increase. An important part of the objective was also to assess which methods can be used practically at Iracambi.The project was carried out during the rainy season from February 13th to April 12, 2012. During this time the water flow was measured at five stations along the river, using a current meter and instant slug-injection. Between six and fifteen flow measurements were made at each station. Slug- injection was generally the most suitable gauging method to use in the area. Precipitation was measured at two points. Evaporation was measured using an evaporation pan, and also calculated using the Penman-Monteith equation. Even though, the parameterization of the Penman-Monteith needs to be improved it was deemed to be the more suitable method for the area.The results give a rough estimate of the water balance during the period. It was concluded that the storage decreased during the project period. Based on the flow measurements and observations it was concluded that the areas covered by forest were less affected by the floods that occurred during heavy rainfalls than the areas covered by grass. Further on, the result of this report indicates that the Iracambi research station can continue to carry out assessments for changes in water flow, rainfall and evaporation with the simple equipment used in this project. However, more expensive and advanced equipment would be beneficial to establish a more accurate water balance. / Idag återstår endast 7% av den atlantiska regnskogen som en gång täckte Brasilien södra kust. Regnskogen försvinner snabbt vilket har lett till att Brasiliens regering de senaste åren visat ett ökat intresse att bevara regnskogen. Fler och fler områden har förvandlats till nationalparker och reservat. I utkanten till ett av dessa reservat ligger forskningsstationen Iracambi. Iracambi bedriver forskning i och runt området för att hitta metoder för att bevara regnskogen och öka kunskapen om området. Detta projekt är ett litet bidrag till detta arbete. Det övergripande syftet med projektet var att upprätta en vattenbalans över floden Graminhas avrinningsområde. Detta är huvudfloden i området och genom upprätta en vattenbalans kan förståelsen för förändringarna av vattentillgången i ekosystemet öka. Ett viktigt mål med projektet var också att finna verktyg som forskningsstationen Iracambi kan använda för kontinuerliga mätningar av de parametrar som ingår i vattenbalansen.Projektets genomfördes under regnperioden mellan den 13 februari och den 12 april, 2012. Flödesmätningarna utfördes vid fem mätstationer längs floden Graminha. Två typer av utrustning användes: flygel och konduktivitetsmätare. Rekommendationen för Iracambi var att fortsätta mätningarna med framförallt konduktivitetsmätaren. Uppskattningarna av avdunstningen genomfördes på två sätt: dels genom upprättandet av en evaporationspanna, dels genom beräkningar. Beräkningarna genomfördes med Penman-Monteith ekvationen och det kunde konstateras att även om de ingående parametrarna innehåller en del osäkerheter, så var detta den mest passande metoden för att beräkna avdunstningen. Nederbörd mättes på två platser med hjälp av enkla regnmätare konstruerade av pet-flaskor.Slutligen upprättades en vattenbalans för området. Utifrån denna kunde det konstateras att vattenmagasinet för hela orådet minskade under mätperioden. Utifrån flödesmätningar samt observationer kunde slutsatsen dras att skogsområdena drabbades mindre än de gräsbevuxna områdena av de kraftiga översvämningarna som uppstod under intensiva regn. Vidare visar resultaten att forskningsstationen Iracambi kan få en bra uppskattning av flödesförändringar, nederbörd och avdunstning med hjälp av den enkla utrustning som användes i detta projekt. / Minor Field Study

Seasonality in the Amazon Rainforest is predicted to become more extreme, with dry seasons increasing in length and severity, while severe episodic droughts are expected to occur with greater frequency. Drought stress can reduce the capacity of the rainforest to sequester carbon, and severe drought events can switch the region from being a net sink to a temporary source of carbon to the atmosphere. A key component in the drought-induced carbon flux is tree mortality, and there is evidence of strong feedbacks globally and regionally in the Amazon with climate change. Although the exact cause of drought-induced mortality in trees is difficult to ascertain, recent data suggests that reduced functionality of the water transport pathway (hydraulic failure) is an important factor. Hydraulic vulnerability in trees is often assessed using measurements of the capacity of stems and branches to cope with the strongly negative internal water pressures associated with drought. However, leaves play a vital role in protecting the integrity of the ‘upstream’ hydraulic pathway by influencing the rate of transpiration and thus the tension in the water column. Therefore, the physiology of leaves can be informative of, and influence, tree species’ sensitivity to drought. This thesis uses a long-term large-scale rainfall exclusion experiment in the Eastern Amazon to examine the possible link between leaf physiology and drought sensitivity (or tolerance) by different taxa, and the capacity of mature, upper canopy Amazonian trees to respond to drought via plastic changes in leaf physiology. The plasticity in response to experimental drought and the differences between taxa classed as drought-sensitive and drought-resistant based on drought induced mortality records were tested by the study of leaf water relations (Chapter 2), leaf anatomy (Chapter 3) and foliar water uptake (Chapter 4). No consistent differences were found between drought-resistant and drought-sensitive species suggesting that the sensitivity of these species to drought may be due to other aspects of plant physiology. However, a limited response to the imposed drought conditions was detected across all taxa and included reductions of osmotic potential at full turgor and turgor loss point (Chapter 2), and increases in the thickness of the upper epidermis and the leaf internal cavity volume (Chapter 3). Interestingly, drought-sensitive taxa showed more seasonal osmotic adjustment than drought-resistant taxa, indicating that short-term responses to drought (e.g. season) are not representative of the capacity for adjustment in response to long-term water deficits. No significant changes occurred in leaf size, thickness, stomatal and vein density, the quantity of the inner leaf tissues (i.e. the palisade and spongy mesophyll) and mesophyll cell size, in response to the experimental drought. The experiments on foliar water uptake in Chapter 4 revealed that this rarely-considered process occurs in all taxa, but the response to the drought treatment differed among taxa. Using a simple model, foliar water uptake was scaled up to canopy level. Under normal conditions (i.e. no drought) canopy foliar uptake was calculated to be 29.9 ± 2.3 mm year-1 from rainfall alone, but this increased to a maximum of 51.9 ± 2.3 mm year-1 when including the input of dew in the dry season. However, lower water potential in the drought plot causing increased rates of foliar water uptake, led to estimates of 38.7 ± 3.0 mm year-1 (rainfall only) and 68.9 ± 2.9 mm year-1 (including dry season dew). Taken together, these results demonstrate that Amazonian trees show some limited capacity for acclimation to drought through the changes in leaf physiology measured in this thesis. Low turgor loss point is associated with dry climate-adapted plants, so the finding that this parameter reduced in response to the drought reveals some potential for Amazonian trees to acclimate with the predicted changes in moisture availability. However, the limited response of leaf anatomy to long-term drought might suggest that acclimation may only occur within a narrow range. The finding that six common Amazonian tree genera can take water up through their leaves has considerable implications for understanding the Amazon water budget, in terms of the contribution of dew and light rainfall to canopy water status, but also the implications it has for the hydraulic vulnerability of trees in rainforests right across the Amazon basin.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第18338号 / 農博第2063号 / 新制||農||1023(附属図書館) / 学位論文||H26||N4845(農学部図書室) / 31196 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 大澤 晃, 教授 髙部 圭司, 教授 北山 兼弘 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM