Effects of Root Air-Pruning on Framework Tree Species Seedlings Production for Forest Restoration in Northern and Southern Thailand

Abstract: Tree planting is a simple tool to bring back the forest area. Therefore, seedling production is one of the important steps in forest restoration. Root pruning can promote the root system development of a nursery tree. However, there are consumed a lot of time and labor. Consequently, Air pruning is another efficient method of propagating seedlings for reforestation projects. The study was aimed to determine the effects of air-pruning technique on the growth rate of framework species seedlings and determined about the production cost. The filed study in Forest restoration research unit (FORRU) tree nursery conditions in Northern and Southern of Thailand. Ten framework tree species studies used to comparing 3 different seedling production processes; 1) using crate - steam lining (COG), 2) air-pruning + crate (CAP) and 3) control (CON). Recorded growth rate of ten tree species every month for 6 month and sixth month collect root dry weight and root architecture included comparison a total cost. The results showed that there was a significant difference (P<.05) of three treatments in their seedling growth rate. In addition, the COG and CAP improved the root system that was effective fibrous root development, reduced mortality rate. Moreover, the economic viability of root airpruning can be reduced total cost and labor. The COG technique was more cost-effective than the other two techniques-producing seedling sat below 20 THB each while CAP may reduce the cost of seedling production in long term time period. Therefore, root air-pruning will also help in preparation processes efficiently and management of seedlings production.