In the southeast of the US longer pine needles from varieties of pines such as slash pine are used for garden mulch. Ironically, this was later in the season than I normally do this, I just laid down 52 bales of mulch in my garden.

Here it is common for a few reasons.

1. It is in-expensive (about $3.75 a bale). 2. It provides insulation to the plant roots to keep the soil warmer in the winter and cooler in the summer. 3. On steep inclines it tends to knit together to stay on the incline to prevent erosion. 4. As it breaks down it amends the soil with nutrients.

The only negative is that you have to add new mulch every year because it mostly breaks down after a year.

People who have pine tree farms use this as an extra revenue source. https://www.aces.edu/blog/topics/business-opportunities-fore... https://www.carolinacreations.biz/blog/mulch-and-pine-straw/