Sawdust use

Question

If my 85 year old father has put sawdust around all our trees as a mulch and I can’t convince him that it harms them, how can I add a fertilizer or additive to help the trees get the nitrogen they need?

Answer 1

Here are some articles that will help you.

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/nitrogen-plant-fertilizer.htm
https://www.gardeningknowhow.com/composting/ingredients/using-sawdust-in-your-compost-pile.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/too-much-nitrogen-soil.htm