Low water availability predicted under climate change is a major abiotic factor limiting plants growth and productivity. In this study a greenhouse experiment was conducted on three important tree species of arid environment: Conocarpus erectus (CE), Acacia modesta (AM), and Salix tetrasperma (ST). Young saplings were subjected to control (C), medium (MWD) and severe soil water deficit (SWD) treatments and response was evaluated. Results showed that in all the three species leaf, stem and root dry weight production remained similar to C under MWD treatment but decreased significantly under SWD. The highest decrease in total dry weight was noticed in ST and the lowest was evidenced in AM under SWD. Root:shoot ratio increased significantly in both CE and AM under MWD and SWD. Furthermore, chlorophyll content decreased while proline content increased significantly in both MWD and SWD treatments. The production of oxidants (hydrogen peroxide and superoxide anions) and antioxidants (superoxide dismutase, catalase, peroxidase and ascorbate peroxidase) increased significantly under both MWD and SWD treatments and were the highest in AM in both MWD and SWD treatments. Therefore, we may conclude that all the three species can tolerate medium water stress due to increased root production and an effective antioxidant defense mechanism.

The economic rotation of two different tree species was calculated during 2020 in two different tehsils (sub-districts) namely Gujranwala and Khushab which are located in Punjab province of Pakistan. Vachellia is a common tree grown on the farmlands of Gujranwala while Eucalyptus is a common tree growing on the farmlands of Khushab. So that these two tree species were selected from two different tehsils of Punjab. Vachellia is grown at a rotation of 10 to 20 years while Eucalyptus is grown on 5 to 12 years rotation. For the evaluation of economic rotation of both tree species, net present worth and benefit cost ratio was calculated. 300 trees of both tree species were randomly selected from their respective tehsils. Different rotations of Eucalyptus were tested viz., 12 years rotation, 6 + 6 = 12 years, 8 + 4= 12 years and 4 + 8 = 12 years, while the total span (12 years) was kept same in all rotations. The total span was kept at 12 years because this tree is grown at a maximum rotation of 12 years on the farmlands. Similarly, different rotations were tested in case of Vachellianilotica viz., 10 years, 5 + 5 = 10 years and 6 + 4 = 10 years with the same total span of 10 years. In case of Eucalyptus, net present worth was found to be Rs. 4035.525, 4506.45, 4310.375 and 4379.175 at a rotation of 12, 6+6 = 12, 8+4=12 and 4+8 = 12 years, respectively. However, best rotation was found to be 6 + 6 = 12 years with highest net present worth. Similarly in case of Vachellia, net present worth was found to be Rs. 4844.532, 5155 and 5675.322 at a rotation of 10 years, 5 + 5 = 10 years and 6 + 4 = 10 years, respectively. rotation of 6 + 4 = 10 years was found to be best. It is recommended that farmers of Khushab should grow Eucalyptus trees at a rotation of 6 + 6 = 12 years. The farmers of Gujranwala are recommended to raise Vachellia trees on a rotation of six years followed by another short rotation of 4 years for more financial benefits.

The research was carried out to determine the effect of Populus deltoides trees on the soil physical and chemical properties and grain yield of wheat crop under the agro ecological conditions of Faisalabad (Punjab), Pakistan. Two fields were selected; one with wheat monoculture and the other had boundary trees of Populus deltoides. The average age of the s Populus trees was 5 years. Number of trees was 40 per acre. The average height and diameter at breast height of trees was 12 meters and 42.43 cm respectively. The wheat crop was sown in October, 2020 in both fields and harvested in April, 2021. A quadrate of one meter square was used to collect the data. The quadrate was put at various distances (2-24 meter) from tree stems and the plants growing there were harvested. The grain yield (gm-2) per quadrate was determined with the help of an electric weighing balance. The soil samples were selected from both fields and various chemical and physical properties of soil were determined. The soil pH was 7.32 and 7.95 in wheat monoculture and  Populus+wheat field respectively. Total nitrogen was 0.05 and 0.08%in both fields respectively as mentioned above. Organic matter was 0.64 and 0.81 in wheat monoculture and Populus based field respectively. The effect of Populus trees on grain yield of wheat was negative form 2m to 10 meter distance from trees. While from 12m to 24 m distance, wheat grain yield was more or less equal in both fields i.e. with and without trees. Net income was Rs. 67437.69 and Rs. 104781.03 per acre without and with trees, respectively. On the basis of this research, it is concluded that wheat + Poplar is more suitable option for farmers. So farmers should adopt this system to generate more money while keeping the inputs same.