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Providing evidence to improve practice

Action: Water plants to preserve dry tropical forest species Forest Conservation

Key messages

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  • One replicated, controlled study in Hawaii found that watering plants increased the abundance and biomass of forest plants.


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.

Referenced papers

Please cite as:

Agra H., Schowanek S., Carmel Y., Smith R.K. & Ne’eman G. (2019) Forest Conservation. Pages 331-347 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.