Comparison of direct-seeding, bare-root and polybag methods on early growth, root structure and plant establishment cost of mahogany (Swietenia macrophylla)

Abstract

Listen

Translate article

ABSTRACT Tropical tree species restoration programs require effective, low-cost plant establishment methods. The aim of this research was to compare seedling survival, growth and cost for four plant establishment methods for mahogany (Swietenia macrophylla), a high-value tree species that is widely cultivated in community forests and industrial forest plantations in Indonesia. A randomised block design with four blocks and four planting-stock types (direct seeding, direct seeding with seed briquettes, planting with bare-root seedlings, and planting with seedlings raised in polybags) was used to assess tree survival and growth at 12 months old at the Parung Panjang Forest Research Station in Bogor, West Java, Indonesia. Estimated costs were calculated based on 1000 target trees for each planting-stock type. The study found that trees grown from polybag seedlings had the highest survival (93.3%) and growth (height, diameter and biomass), as well as greatest taproot length and biomass, although the root structure was spiral due to suboptimal root growth in the nursery. Trees raised from direct seeding with seed briquettes had the second-highest survival rate (67.7%) and better sturdiness quotient, basal root numbers and biomass, with a more naturally developed root structure, and trees grown from bare-root seedlings had the worst growth performance and root structure. In terms of plant establishment costs, the cost of direct seeding with seed briquettes was almost half that of planting polybag seedlings and may have lower environmental impact because it avoids plastic waste. Therefore, direct seeding with seed briquettes can be recommended as an alternative method of forest and land rehabilitation using mahogany, especially in remote areas.