Department of Forest Protection and Conservation

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    The Effects of Windbreaks on Citrus sinensis (Oranges) in Shabwa and Marib Governorates of Eastern Yemen
    ( University of Khartoum, 2015-06-22) Ali Salih Ahmed Sylan ; Abd El Aziz Mohamed Saeed Bayomi ; Forest Conservation and Protection
    This study was done in each of Wadi Beihan (Shabwa Governorate) and Wadi Saba (Marib Governorate) in eastern Yemen during the period May to October 1997. The study investigates the role of windbreaks in protecting orange orchards from damages caused by strong winds and the benefits arising from this on vegetative growth and fruiting. Sixteen orange orchards were selected randomly; 8 of them with windbreaks and the other 8 without. Twelve orchards were selected in Wadi Beihan, 8 of them in the fruiting stage (5 years old) and 4 in the non-fruiting (1.5 - 2 years old). The remaining four orchards were selected in Wadi Saba; they were all at the fruiting stage (10 years old), 2 of them with windbreaks and 2 without. The studied windbreaks consisted of one row of trees and of various species. The climatic factors measured included wind speed, air temperature and relative humidity. They were measured outside and inside the selected protected and unprotected orchards. Also the effect of windbreaks on vegetative growth was measured e.g. on tree height, crown diameters and branch numbers. Also fruiting growth, including fruit number, fruit weight and fruit quality was measured on 25 trees selected along five vertical rows and five horizontal rows in each orchard. In addition to that useful information was collected through a questionnaire, 50 copies of which were randomly distributed; 36 copies in Wadi Beihan and 14 copies in Wadi Saba to include 25 farmers with windbreaks and 25 without windbreaks in both sites. The data collected from the field experiment was analyzed by a computer program and the questionnaire information by frequency distribution. The field experiment results showed the following facts: 1. Windbreaks have significantly decreased wind speed on both leeward and windward sides of the windbreaks. The reduction was 92.7% on leeward side and 34% on the windward side at a distance of 2.5H (It is the windbreak height) in the two sites. Relative humidity was significantly increased at 2.5 H on the leeward side while temperature was insignificantly increased on the leeward side, also at 2.5 H. 2. The effect of windbreak on microclimate had a positive effect on vegetative growth and fruiting as follows: a. In Wadi Beihan: The heights of orange trees were significantly increased while increase in crown diameters and branch numbers was insignificant. Also fruits number and its weight per tree was significantly increased as well as the production per hectare. The increase in the latter was 39.5% more compared to the production of the unprotected orange orchards. b. In Wadi Saba: The increases were insignificant for both vegetative growth and fruiting, the latter was 12.68%. This smaller increase in Wadi Saba may be due the narrow spacing between orange trees (3  6 m) compared to the wider spacing (66 ) in Wadi Beihan. 3. The study showed that windbreaks were important especially in the early life of the orange orchards ie (Before fruiting stage). They gave protection against harmful wind and produced symmetrical and significant growth increases in both height. and crown diameters whereas growth of unprotected orchards was unsymmetrical, showing what is known as flag appearance. The questionnaire results showed the following facts: 1. The unprotected orchards were more affected by strong winds and sand, encroachment compared to orchards protected by windbreaks. 2. Farmers who had windbreaks were fully aware of windbreaks importance and benefits. For farmers without windbreaks awareness to establish windbreaks in their farms were increased. 3. That the suitable trees for windbreaks in Wadi Beihan were Zizyphus spina-christi, Acacia salicina and Casuarina equestifolia while in Wadi Saba they were Tamarix stricta, Acacia salicina and Casuar equestifolia. The farmers avoided Eucalyptus sp. and Prosopis because of their competition with orange trees. 4. That reasons for not establishing windbreaks in the past were fear of attraction of birds to their crops, scarcity of water and small land area 5. That modern irrigation methods like drip irrigation because of its water economies my be the main reason for the large extension in Citrus plantations in the recent times. The study recommendations are as follows: 1. Windbreaks should be planted using local tree species like Zizyphus spina christi and Tamarix stricta and introduced species such Casuarina sp. and Acacia salicina which proved successful. Eucalypi sp. may only be used in shelterbelts to protect villages and cities and forestry plantations for production of wood. 2. That the most suitable spacing between orange trees is 66 m with the necessary care in agricultural operations such as weeding fertilization, irrigation and pruning at the appropriate time. 3. That the Ministry of Agriculture and Irrigation and Ministry of Oil an Mineral Resources should coordinate their efforts in making the Petroleum Exploration Companies assist in the establishment of shelterbelts and windbreaks to protect farms and villages from smoke and poisonous gases caused by their explorations in the study areas. 4. Forestry and agricultural extension services should increase their efforts to convince farmers of the importance of windbreaks. 5. That the research centers investigate the phenomenon which appeared lately on Citrus trees causing drying of trees and solidification of juice in fruits.
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    Assestment Of The Role Of Forests As A Natural Rangeland Case: El Rawashda Forest, Gadaref State, Sudan
    (University of Khartoum, 2015-04-23) Yousif Elnour Yagoub Babiker ; Awad Osman Abusuwar ; Forest Conservation and Protection
    The main objective of this study was to assess the role of El Rawashda Natural Forest Reserve as a natural rangeland and the impact of grazing in terms of deforestation and replacement of palatable species by unpalatable species and the possibilities of finding solutions to these problems. Two types of data were user for this study; namely, primary and secondary data which were collected during the period 2008 - 2009. The primary data were collected through social survey as faceto- face interviews with pastoralists and local communities in the study area and by a field experiment on an area of 20 feddans and affected by grazing in the forest. The experimental area was divided into 5 blocks, each block consisted of 4 treatments, namely, seeds of grass and talih (Acacia seyal) were broadcast seeding just before autumn, seeding after disc ploughing, sowing using water harvesting technique and a control (no seeding).The secondary data were collected from the Range and Pasture Administration and the Forest National Corporation (FNC). There were distinct ecological changes in the study area as indicated by the deterioration of the rangelands and retrogression where some palatable weed species disappeared from the study area and were replaced by other unpalatable species due to open grazing pressure, illegal tree felling by the local people and expansion in the rain fed mechanized agricultural schemes due. Moreover, overgrazing represents a real challenge to the conservation and rehabilitation of El Rawashda Forest in the absence of proper protection and management. In addition, the number of animals is more than the carrying capacity of the forest and this resulted in the disappearance of some palatable species and the appearance of new VI unpalatable one. Frequent drought cycles (climate change and variability) and fires also contributed to the deterioration of the forest. The results of the experiment revealed significant differences among some treatments used to improve and tree cover. The seeding of the forage and talh seeds after disc ploughing gave the best results compared to other treatments, followed by forage and talh seed sowing under water harvesting technique and broadcasting of forage and trees seeds and finally the control. In conclusion the deterioration of the natural rangelands in El Rawasha Forest Reserve is due to the existence of livestock in the forest area for a long period of time. This resulted in retrogression where palatable species were replaced by less or unpalatable species. The best method for the rehabilitation of the forest is the adoption of forage and talh seeds broadcasting with ploughing using disc harrow. Consequently, it is a must to rely on the disc harrow and the adoption of water harvesting and broadcasting of forage and talh seeds for the rehabilitation of El Rwashda Forest Reserve
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    Assessment of Agroforestry Extension in Areas Affected by Refugees. Case study; Eastern Sudan
    (University of Khartoum, 2015-04-18) Burae Balla Elhussien ; El Amin Sanjak
    Eastern Sudan has received massive waves of refugees fleeing from civil war and other natural calamities. The pressure exerted on the limited natural resources around the refugee’s camps and adjacent villages reflected in intensive removal of the natural vegetation. Recently, the Government of Sudan and UNHCR paid attention to the problems and sufferings of refugees and nationals living in the affected areas. Accordingly, some projects were formulated to deal with the problem for sake of promoting environment friendly activities. Three Sudanese villages and three refugees' camps from Kassala and Dedarif States were selectedfor this study. The Broad objective of the research is to investigate the possibility of adoption of agroforestry interventions on sustainable basis for sake of mitigating irrational use of the natural resources. Two types of data were used in the research, namely; primary and secondary data. The former was collected through interviewing and group discussion and the later was collected from reports and other documents. The main findings of the research are; the extension staffs are well organized and they were successful in sensitizing and mobilizing the target groups beside the formation of contacts groups to enhance the adoption of the agroforestry extension. The activities introduced in the study area meet the needs of the target group. Two methods of extension is applied in the study area (home visits and meetings) with a satisfactory level of training. The main pitfalls of the project are; lack of encouraging participation of the target group from the early stages of the project cycle, besides focusing in forestry extension with limited extension services in the agricultural fields.