Plastic bottle crates give thai tree seedlings better odds of survival in reforestation efforts

A simple yet ingenious solution using everyday plastic bottle crates is revolutionizing tree restoration efforts in Thailand’s tropical forests. Researchers at Chiang Mai University’s Forest Restoration Research Unit have discovered that growing native tree saplings inside repurposed beverage crates dramatically improves their survival rates and growth potential compared to traditional nursery methods.

The breakthrough addresses a critical problem in tropical reforestation projects worldwide. Typically, Thai nurseries grow seedlings in black plastic bags placed directly on the ground—a method that creates significant challenges. As saplings develop, their roots often spiral within the confined bag space, leading to poor root structure. Even worse, roots frequently break through the bags and anchor into the soil below, meaning that when seedlings are transplanted, up to half their root system gets left behind in the nursery ground.

“You’re immediately reducing the capacity of the plant to absorb water on the day that it’s being planted into a harsh, dry, deforested environment, where it’s going to compete against the weeds,” explains Stephen Elliott, the research unit’s associate professor and director. “You’re putting it at a disadvantage.”

The bottle crate innovation solves this problem through a process called “air pruning.” By elevating the bagged seedlings off the ground within the crates, roots that would normally grow through the bags are instead naturally pruned by exposure to air, promoting healthier, more compact root systems. This low-cost hack could significantly boost the success rates of restoration projects across the tropics, where reforestation efforts are critical for combating climate change and biodiversity loss.