Hi @rishad,
A warm welcome to the Bunnings Workshop community and thank you for your question.
You might like to start by reading through How to diagnose a sick plant. This should give you some good general information on common ailments in plants.
As your pencil pine is drying, it seems logical that the issue is related to water. The main things to look at are the watering schedule and the soil conditions.
Are you watering them regularly? If so, what is your current watering schedule? Can we get some photos of the soil? Does it drain quickly or retain moisture for long periods of time?
Ideally, they will be watered deeply 1-2 times a week depending on the soil conditions. Before watering, check the soil to see how much moisture is present. This can be done by sticking your finger into the first 5-10cm of soil beneath your tree. If it is still damp, wait a day or two, if it is dry then water it deeply.
If the soil is in poor condition, this can affect its ability to retain moisture and thus deprive the tree of water. Mixing compost into the soil around the base of the tree can help with water retention and give your tree the nutrients that it needs to thrive.
Additionally, you can add a plant tonic, such as Seasol to give your tree a boost of nutrients to help it get through this rough patch.
Allow me to tag @mich1972 and @Noelle to see if they have any other advice they can add.
Let me know if you have any further questions.
Jacob
