Water plants to preserve dry tropical forest species

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

65%
Certainty

18%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

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.

Study locations

Key messages

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

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

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.
Study and other actions tested
Referenced paper
Cabin R.J., Weller S.G., Lorence D.H., Cordell S. & Hadway L.J. (2002) Effects of microsite, water, weeding, and direct seeding on the regeneration of native and alien species within a Hawaiian dry forest preserve. Biological Conservation, 104, 181-190.

Please cite as:

Agra, H., Schowanek, S., Carmel, Y., Smith, R.K. & Ne’eman, G. (2020) Forest Conservation. Pages 323-366 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Forest Conservation

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