Action: Water plants to preserve dry tropical forest species
Key messagesRead our guidance on Key messages before continuing
- One replicated, controlled study in Hawaii found that watering plants increased the abundance and biomass of forest plants.
Direct planting of new trees can be used to restore degraded tree communities. This can also affect the abundance of other plant species and consequently the composition of the whole forest.
Supporting evidence from individual studies
A replicated, controlled study in 1998-2000 in tropical dry forest in Hawaii, USA (Cabin et al. 2002) found that irrigation increased the abundance and biomass of most forest plants. Average biomass and density were higher in watered than in control plots for: all species (watered: 355 g/m2, 28 individuals/m2; control: 28 g/m2, 23 individuals/m2), for native species (watered: 129 g/m2, 16 individuals/m2; control: 7 g/m2, 11 individuals/m2) and for seeded species (watered: 34 g/m2, 7 individuals/m2; control: 1 g/m2, <1 individuals/m2). For non-seeded species average biomass was higher in watered (95 g/m2) than in control plots (6 g/m2), while density was lower in watered plots (watered: 9; control: 11 individuals/m2). Thirty two plots (1 m2) of each treatment: watered (20 litre/plot, three times a week for the first six months, once a week thereafter) and control (not-watered) were established in 1998. Each plot was sown with 60 seeds of shrubs and trees. Plants biomass and density was measured 21 months after treatment.