After laminectomy for removal of spinal tumor at l3-4, will the spine still have the same strength for weight bearing and exercise as before surgery?

Should be fine: Of course with a laminectomy they're removing a portion of the vertebrae. However there still stability and since no fusion was required you should be fine.

It will take some ti: Laminectomy does weaken the spine for some time. You will have to let the area heal over a period of 3-4 weeks. Then gradually increase your activity to strengthen your back muscles. Walking is a good way to begin this process. A Physical therapist can better guide you in muscle strengthening exercises for your back. Over a period of 6 to 12 months you will regain most of your strength. But go slo