Five-year-old Gmelina arborea, Khaya senegalensis and Tectona grandis seedlings were investigated at Sarabium Plantation, located in North Eastern Egypt, allocated for wastewater disposal. The study monitored the growth, above ground biomass, water use efficiency, nutrients and heavy metals content of these species throughout three seasons (2016, 2017 and 2018). The study was laid out on a randomized complete block design in split plot layout with three replications. There were 12 treatments including three irrigation treatments (A1) approximately 130 %; (A2) 100 %; and (A3) 70 % of evapotranspiration. These amounts of water was applied as main plot and four types of micro irrigation systems: bubblers (Bub.), on line dripper (Drip.), built-in dripper (G.R.) and sub-surface drip irrigation (SSD), as sub-plot factor. The results showed that using bubblers system together with the application of 10.3 l tree -1 day -1 of wastewater could be recommended in Sarabium area where water is not a limiting factor to provide the highest growth parameters and biomass production of Gmelina arborea, Khaya senegalensis and Tectona grandis tree species. Also, values of water use efficiency indicated that 0.76, 1.01, 1.33 and 2.4 m 3 of water were needed to produce one kilogram of dry matter yield using Bub., Drip., G.R., and SSD in Gmelina arborea; 0.59, 0.74, 0.97, and 2.0m 3 in Khaya senegalensis and 0.24, 0.40, 0.57, and 0.76 m 3 in Tectona grandis, respectively. This means that water savings were achieved with the Bub. system in comparing with Drip., G.R. and SSD were 0.25, 57, and 1.64 m 3 in Gmelina arborea; 0.15, 0.38, 1.41 m 3 in Khaya senegalensis and 0.16, 0.33 and 0.52 m 3 in Tectona grandis, respectively. The results of the present study could contribute in the Egyptian sustainable development strategy 2030, as it achieves the target of "managing the natural resources" through forestation the desert land and reuse the wastewater to produce woody biomass.

This study was carried out at the nursery of Horticulture Research Institute, Giza, Egypt in the two seasons, 2016 and 2017, aiming to investigate the effect of salicylic acid at different level (0, 0.5, and 1.0 g/l) with different levels of field capacity (25,50,75 and 100%) on growth and chemical constituents of Taxodium distichum and also to reduce the amount of water needed for irrigation. Main results of this study could be summarized as follows: The highest value was achieved by the following treatments: salicylic acid at 0 g/l with100% of field capacity level (concerning root fresh and dry weights); salicylic acid at 0.5 g/l with 75% of field capacity level (for plant height, branch number, shoot dry weight, root fresh and dry weights); salicylic acid at 0.5 g/l with 100% of field capacity level (regarding plant height, branch number and root length); salicylic acid at1.0 g/l with 75% of field capacity level (for plant height, root length and root fresh weight); and salicylic acid at 1.0 g/l with 100% of field capacity level (for shoot fresh weight, total carbohydrate and total chlorophyll). The lowest value was obtained by the following treatments: salicylic acid 0 g/l with 25% of field capacity level (for plant height, branch number, shoot fresh and dry weights, root fresh weight, total carbohydrate and total chlorophyll); salicylic acid at 0 g/l with 50% of field capacity level (for plant height and shoot dry weight); salicylic acid at 0.5 g/l with 25% of field capacity level and salicylic acid at 0.5 g/l with 50% of field capacity level (for root fresh weight); salicylic acid at 0.5 g/l with 100% of field capacity level (for root dry weight); salicylic acid at 1.0 g/l with 25% of field capacity level (for root length and shoot dry weight); and salicylic acid at 1.0 g/l with 50% of field capacity level (for shoot dry weight). It is recommended to treat plants with salicylic acid at 0.5 g/l and to apply irrigation at 75% of field capacity level capacity to obtain the highest values of plant height, branch number, shoot dry weight, root fresh and dry weights. This will also save as much water as 25% of field capacity level.

This is the first study to measure the diversity of woody taxa in Giza Zoo garden considered an extraordinarily diverse hotspot with an unusually high number of woody taxa found nowhere else in Egypt especially, tropical species. This study was conducted in several stages, preparation, inventory, analysis, and evaluation. The study uses quantitative methods to evaluate the woody taxa diversity and the threatened species which are conserved in the garden across their main sections. Therefore, species richness, Shannon and Simpson's diversity indices were estimated. Also, the species importance value index, a measure of how dominant a species is in a given population, and conservation status were used to evaluate the conservation potential of the trees in the garden. The garden plays a vital role in conserving 145 individuals as threatened trees belonging to 18 species that are either endangered, near threatened or vulnerable according to the IUCN red list. The Weak conservation procedures in the zoo garden have led more individuals of species that are over-mature and over-aged to their demise therefore, it is feared that may be lost from the garden. So, it's imperative to immediately restore these lost species in the garden and place their diversity on a pathway to recovery. We warn to increase the area of impermeable pathways and more buildings that will increase the stresses upon the garden trees. Therefore, we suggest technical support for the botanic garden as the experts of the Timber Trees department will be essential for allowing this valuable garden to continue its work and expand its collections of critical but under-represented species. Also, the inventory of tree species entity and structure in this study will assist as a guide tool for the administration of the garden to reach the Egyptian sustainable development goals by 2030 and the global goals by 2050.

Jatropha curcas L. was cultivated in Abou Rawash, 6 th October Governorate, Egypt. The plants were irrigated at three different intervals (7, 14 and 21 day) using sewage water receiving primary treatment from Abou Rawash Station and were fertilized with calcium superphosphate (15% P 2 O 5 ) and potassium sulphate (50% K 2 O) every 2 months at rates of 0:0, 50:25, 75:37.5 and 100:50 g/plant.The obtained results indicated that 7-day irrigation intervals gave the best vegetative growth, fruit yield and oil percentage in seeds, followed by 14-day intervals but 21 days intervals gave the lowest value.Plants fertilized by 100:50 and 75:37.5 g/plant P 2 O 5 :K 2 O gave the highest values for vegetative growth, fruit yield and oil percentage as compared to other fertilizer treatments.The fertilization treatment of 100:50 g P:K/ plant combined with 7-day irrigation intervals increased vegetative growth, fruit yield and oil percentage as compared to other treatment combinations.

Aims: Mangroves are woody trees or shrubs that grow in the intertidal zone and are distributed along tropical and subtropical coasts. These plants are resilient to various environmental challenges; they are also one of the most efficient terrestrial and coastal ecosystem for carbon fixation and storage. In recent years, mangrove reforestation has attracted much attention as a strategy to reduce the effects of climate change. In Egypt, there are two types of mangroves, Rhizophora mucronata and Avicennia marina, between 30°N and 30°S of the equator. Mangrove management presents a difficult task, particularly when it comes to managing molecular mangroves for long-term sustainability. With the impact of human activity on mangrove ecosystems increasing each year, molecular research on mangrove correlates remains to be conducted. For this reason, using DNA barcoding technology to quickly identify species, mangrove ecosystems may be protected. Methodology: In this work, the two Egyptian mangrove species were assessed through morphological, cytological, and molecular approaches. Two universal DNA barcodes, rbcL and ITS, were examined to identify their efficacy for Egyptian mangrove species identification and phylogenetic reconstruction. Results: According to pairwise alignments, the rbcL region had the highest level of variability (73.2%), whereas the ITS region was the least variable (11.96%). The selected Egyptian mangrove species can potentially be distinguished by barcoding loci rbcL and ITS due to the existence of distinctive variable sites.